The Coral Triangle is a tropical marine region between the Pacific and Indian oceans where 76% of Earth's coral species are found. It encompasses 2.3 million square miles (6 million square kilometers) of ocean around the Philippines, Indonesia and Papua New Guinea, and stretches south to Timor-Leste and as far east as the Solomon Islands.

Biodiversity in the Coral Triangle is much higher than in other regions with coral reefs, such as the Caribbean Sea and the southwest Pacific Ocean. Around 605 reef-building coral species inhabit the Coral Triangle — 10 times the number in the Caribbean Sea, according to an article from the U.K.'s Natural History Museum (NHM).

These corals provide a home for six of the world's seven sea turtle species and 37% of the world's coral reef fish species, as well as marine mammals like dolphins, dugongs, blue whales and sperm whales, according to the NHM article. This incredible array of species has earned the Coral Triangle the nickname the "Amazon of the sea."

"This part of the world contains the highest diversity of marine species," Nadia Santodomingo, a coral expert and marine biologist at the NHM, said in the article. "Scientists have been trying to understand why it's so diverse for a very long time." In fact, British naturalist and explorer Alfred Russel Wallace was working there when Charles Darwin was alive, trying to solve the same problem, she added.

Wallace traveled through the Malay Archipelago between mainland Southeast Asia and Australia, collecting specimens and developing theories regarding the region's staggering biodiversity. He came up with what scientists call the "Wallace Line" — a gigantic biological boundary that separates the Oriental and Australian faunal regions — and proposed the theory of evolution by natural selection around the same time as Darwin.

Scientists today have more tools at their disposal to understand the region, with evidence suggesting that murkier conditions in the Coral Triangle compared with other shallow tropical waters may provide a haven for different species. The Coral Triangle has been a biodiversity hotspot for at least the past 20 million years, and this is partly thanks to a huge variety of habitat types and optimal conditions for larvae that ride on ocean currents, according to the nongovernmental organization Blue Corner Marine Research.

Research also suggests that the Coral Triangle has a plethora of species simply because diversity built up over time. Unlike temperate and polar marine regions that have undergone glaciations, tropical regions like the Coral Triangle have remained relatively stable. And what sets this region apart from other tropical seas is its unique, platform-like geology and location at the intersection between two oceans, researchers say.

Like other coral reef regions, the Coral Triangle is vulnerable to overfishing, pollution from coastal development, and ocean acidification linked to climate change — although scientists think its murky conditions may shield it somewhat.

"Corals living under continuous sediment stress seem to be more resilient, as the mud may block light, which in turn alleviates bleaching stress induced by high temperatures," Kenneth Johnson, a paleobiologist and principal researcher at the NHM, said in the article.

Nevertheless, it's important to protect this patch of ocean, Johnson said. "Nobody really thinks about these reefs," he said, "but they might be the ones we really want to protect."

Discover more incredible places, where we highlight the fantastic history and science behind some of the most dramatic landscapes on Earth.

The world's largest deep-sea coral reef, which spans an area roughly the size of Vermont, has been uncovered "right on the doorstep" of the southeast U.S. coastline, new seafloor maps reveal. The dark-dwelling, ghostly corals likely support a wide variety of marine creatures that we didn't know were there, researchers say.

In a new study, published Jan. 12 in the journal Geomatics, scientists collated data from 31 multibeam sonar mapping surveys and 23 submersible dives to build a map of the Blake Plateau — a massive sloping shelf located around 100 miles (160 kilometers) off the U.S. coastline between North Carolina and Florida.

The new maps revealed thousands of previously unknown "mounds" of deep-sea corals, also known as cold-water corals, spread almost continuously across an area covering 6.4 million acres (2.6 million hectares) between 1,640 to 3,280 feet (500 to 1,000 meters) beneath the surface. The highest abundance of corals was located in an area the researchers dubbed "Million Mounds," which is around 158 miles (254 km) long and 26 miles (42 km) wide.

Related: 10 mind-boggling deep sea discoveries in 2023

The highly complex network of corals is "the largest deep-sea coral reef habitat discovered to date," researchers wrote in a statement.

Marine scientists have known that the Blake Plateau harbors deep-sea corals since the 1960s. But until now, they lacked the technology and funding required to properly assess how abundant they are, study lead author Derek Sowers, an oceanographer at the University of New Hampshire and mapping operations manager for the non-profit organization Ocean Exploration Trust, told Live Science in an email.

"We knew there would be many coral mounds to map here," Sowers said. But it was "impressive and surprising" to reveal just how many of the mounds there really were, he added.

The coral expanse lies directly beneath the Gulf Stream — a deep, nutrient-rich current of warm water that runs northward along the eastern U.S. coast. The researchers believe this subsurface superhighway likely provides the corals with all the food they need to thrive in such large concentrations. 

It's possible there could be even larger deep-sea coral reefs waiting to be found beneath other similar ocean currents across the world, Sowers said.

Related: What percentage of the ocean have we mapped?

Deep-sea coral reefs are very different from tropical coral reefs. They dwell in waters that can reach as cold as 39 degrees Fahrenheit (4 degrees Celsius) and can live for thousands of years. 

Unlike tropical reefs, the deep-sea variants are mainly white because the cold water corals do not harbor the same colorful symbiotic algae that give their warm-water counterparts vibrant hues and provide them with energy via photosynthesis. As a result, they look very similar to tropical reefs that have experienced coral bleaching — a disease where heat-stressed corals expel their symbiotic algae and die off.

The newly discovered reefs are made predominantly of one species of coral, Desmophyllum pertusum (formerly known as Lophelia pertusa), with a small mix of other corals from the genera Enallopsammia and Madrepora. These few species provide a home to countless other creatures, including sharks, octopuses, crustaceans, swordfish, eels, sea stars, sponges and worms, as well as commercially important fish species like hake, Sowers said.

Most of the newly mapped reefs lie within a protected area, known as a Habitat Area of Particular Concern, which was created in 2010, Sowers said. This means the corals are shielded from destructive seafloor fishing practices that threaten other unprotected reefs around the globe, he added.

The deep sea is an enigmatic, alien world. But every year, scientists make discoveries about the ocean's depths that help to fill in parts of the puzzle, and this year was no different. From gigantic seamounts and the deepest-dwelling fish to a mysterious golden orb and puzzling methane leaks, here are the 10 best deep-sea discoveries of 2023.

Gigantic seamount 

In November, researchers mapping the seafloor near Guatemala discovered a gigantic underwater mountain, or seamount, that is twice as tall as the world's tallest building, the Burj Khalifa. 

The 5,250-foot-tall (1,600 meters) cone-shaped structure, which lies 7,870 feet (2,400 m) below the ocean's surface, is the remnant of an ancient underwater volcano and covers around 5.4 square miles (14 square kilometers). Researchers discovered it using multibeam sonar during a six-day crossing between Costa Rica and the East Pacific Rise — a tectonic plate boundary in the mid-Pacific Ocean.

Seamounts provide crucial rocky habitats for deep-sea corals, sponges and a host of invertebrates. Experts estimate that there are at least 100,000 undiscovered seamounts in the world's oceans.

Seafloor heat waves 

In a March study, researchers revealed that some of the ocean's deepest points have likely been experiencing previously unknown heat waves that threaten the creatures living there.

Heat waves near the ocean's surface, which are the result of human-caused climate change and oceanographic phenomena such as El Niño, have been documented for decades. But a computer model using surface temperatures and ocean currents showed that the seafloor is probably also experiencing what researchers refer to as "bottom marine heat waves." 

These deep-sea heatwaves can be even more extreme and last longer than surface heat waves, the models revealed.

Seafloor ecosystems are often populated by lobsters, scallops, flounder, cod and other commercially fished creatures, which means bottom marine heat waves could have serious financial implications as well as being ecologically destructive. 

 Mysterious golden orb 

In September, National Oceanic and Atmospheric Administration (NOAA) researchers dredged up a mysterious golden orb from the seafloor in the Gulf of Alaska. Initial analysis revealed it was "biological in origin" — but scientists had no idea what it was.

Researchers plucked the golden orb from a seamount around 10,825 feet (3,300 m) below the surface using a remotely operated vehicle (ROV). The mysterious object was around 4 inches (10 centimeters) wide and appeared to be attached to a rock. When it was pulled to the surface it lost most of its structure and "melted" into a gloopy pile.

Scientists were divided on what the orb was — some thought it was an egg case and others suspected it was a sponge, while others noted it could also be something else entirely. And the orb's identity is still unknown.

The orb's gold color is also a mystery. "Since no natural light penetrates to these depths, it's often hard to determine why certain colors emerge," researchers wrote.

Egg-covered volcano 

In July, researchers explored an ancient deep-sea volcano off Canada's Pacific coastline and discovered that it was surprisingly still active — and covered in up to 1 million football-size eggs.

The underwater mountain, which towers 3,600 feet (1,100 m) above the seafloor, was spouting warm, nutrient-rich water that sustained a thriving ecosystem of deep-sea corals and a nursery for Pacific white skates (Bathyraja spinosissima) — little-known sea creatures related to sharks and rays.

The skates had laid countless rectangular-shaped eggs, known as mermaid's purses, on the seamount. Scientists estimated there could be anywhere from 100,000 to over a million eggs in the area. When these eggs hatch, the seamount likely provides an ideal habitat for the juveniles to grow before heading into the wider ocean.

Baffling methane leak 

In August, researchers discovered an enormous, puzzling methane "leak" coming from the bottom of the deepest point in the Baltic Sea. 

The team found that the greenhouse gas was "basically bubbling everywhere" from an area covering roughly 7.7 square miles (20 square km) — around 4,000 soccer fields — at a depth of about 1,300 feet (400 m). 

The bubbles were also rising much higher than similar methane emissions across the globe. Normally, methane gets dissolved in deep waters and rarely travels more than a few hundred feet above the seafloor. But the gas rising from this area reached up to around 65 feet (20 m) below the ocean's surface, which is "completely new." 

The researchers think the methane is coming from decaying organic matter on the seafloor, but it is unclear why there is so much of it and why it is rising so high up in the water column. 

 Deepest-dwelling fish ever 

In April, scientists released eerie footage of a group of ghostly white fish swimming around the seafloor more than 5 miles (8 km) beneath the waves in one of the world's deepest trenches.

The unidentified species of snailfish, which likely belongs to the genus Pseudoliparis, was spotted by researchers controlling an ROV in the Izu-Ogasawara Trench near Japan at a depth of 27,349 feet (8,336 m), which is more than 500 feet (150 m) deeper than any fish have been seen before.

The immense pressure at this depth would crush most fish. But snailfish have replaced their scales with a gelatinous layer that helps absorb this pressure. The snailfish also contain special chemicals that protect them on a cellular level.

On the same expedition, researchers trapped and dragged up two snailfish in the nearby Japan Trench at a depth of 26,319 feet (8,022 m), which makes them the deepest fish ever caught by humans.

Deep-sea coral reefs 

During a 30-day expedition off the coast of Ecuador, ocean explorers discovered a pair of pristine, deep-sea coral reefs near the Galápagos Islands.

The reefs sit at around 1,000 feet (300 m) beneath the ocean surface, which is much deeper than most coral reefs, and the larger of the two is more than 2,600 feet (800 m) long. 

The reefs feature a rich diversity of stony coral species that have likely thrived there for thousands of years. They are home to lots of other creatures including crustaceans, anemones, brittle stars and urchins. 

The expedition also confirmed the existence of two seamounts in the nearby area, which scientists had previously detected in satellite data.

'Pristine wilderness' under threat 

In a May study, researchers revealed that one of the most promising sites for future deep-sea mining activities is home to more than 5,000 newly identified animal species, which could all be in imminent danger if humans start mining the area.

The Clarion-Clipperton Zone is a large seafloor deformation that stretches from Mexico to Hawaii and covers around 2.3 million square miles (6 million square km), which is around 3.5 times the area of Alaska. It is covered in potato-size spherical nodules that are rich in highly desired metals such as manganese, cobalt and nickel, as well as small concentrations of extremely valuable rare earth elements.

Researchers analyzed more than 100,000 individual records collected from the area and estimated that 90% of the species they identified could be new to science. Deep-sea mining, which could begin properly in the next few years, could threaten all of these species. 

"With the possibility of mining looming, it's doubly important that we know more about these really understudied habitats," researchers wrote.

Hidden underworld 

In August, scientists exploring a hydrothermal vent field in the Pacific Ocean discovered a hidden ecosystem buried beneath mini volcanic cones. 

The hydrothermal vents, which are located in the East Pacific Ridge near Central America, have been studied for more than 40 years. But for the first time, researchers looked beneath the vents by scraping away the ocean bottom sediment using the robotic arm of an ROV. In doing so, they discovered a wide diversity of sub-seafloor creatures including worms, snails and deep-dwelling octopuses.

"This truly remarkable discovery of a new ecosystem, hidden beneath another ecosystem, provides fresh evidence that life exists in incredible places," researchers wrote.

 'Mind-boggling' volcano map 

In April, researchers published a "mind-boggling" map of more than 19,000 underwater volcanoes across the globe, most of which were newly discovered.

Researchers used radar data from multiple satellites to complete the map. The satellites looked for tiny deviations in gravity created by the seamounts and were able to spot underwater mounds as small as 3,609 feet (1,100 m) tall. 

The team thinks the map could help scientists learn more about ocean currents, plate tectonics and climate change.

The map is one of the most complete seamount compendiums ever created, but researchers still think there are thousands of undiscovered structures littering the seafloor.

Ocean explorers have discovered two pristine, deep-sea coral reefs near the Galápagos Islands and put two uncharted seamounts off the coast of Ecuador on the map.

The larger of the two cold-water reefs is over 2,600 feet (800 meters) long, according to a statement. Both reefs sit 1,000 feet (300 m) beneath the ocean surface in the Galápagos Marine Reserve and boast a rich diversity of stony coral species that have thrived there for thousands of years.

"The Galápagos Marine Reserve is an area of outstanding biological significance," Stuart Banks, a senior marine scientist at the non-profit Charles Darwin Foundation, said in the statement. "Finding such deep and long-lived reefs takes us important steps closer to protecting hidden dimensions of ocean diversity and understanding the role that deep habitats play in maintaining our ocean's health."

Related: What percentage of the ocean have we mapped?

Researchers found the coral reefs during a 30-day expedition to study underwater cliff ecosystems around the Galápagos Islands. They used a remotely operated vehicle (ROV) to capture images of colorful species supporting other forms of life, including crustaceans, anemones, brittle stars and urchins.

The expedition also confirmed the existence of two seamounts in the sea reserve, which scientists had previously detected in satellite data. The team charted the features using a laser scanner that creates extremely high-resolution maps. These maps are so detailed individual animals living on the seafloor can be picked out.

The researchers also created detailed maps of the newly discovered coral reefs, which encrust vertical rock faces spanning depths between 1,200 and 1,400 feet (370 to 420 m). These aren't the first cold-water reefs found in these waters, however: In April, scientists documented the first deep-sea coral reef found in the Galápagos archipelago on the summit of a previously unmapped seamount. 

"We are thrilled our mapping data are able to improve our understanding of reef ecosystems in the Galápagos," Katleen Robert, a researcher at Memorial University of Newfoundland's Fisheries and Marine Institute in Canada who led the recent expedition, said in the statement.

The expedition also ventured northeast of the Galápagos archipelago to protected waters off a remote volcanic island known as Cocos Island. There, the team observed more deep-sea corals covered with eggs, according to the statement.

"These fascinating new findings continue to feed important research to inform better management of existing and future marine protected areas in the region," Banks said.

An unusual, all-female assembly of great hammerhead sharks has been gathering in the tropical waters of French Polynesia every summer for over a decade, with numbers peaking around the full moon, scientists have discovered.

These critically endangered sharks convene during the austral summer, between December and March, around openings in two neighboring atolls — Rangiroa and Tikehau — in the Tuamotu archipelago. An atoll is a ring-shaped island or coral reef enclosing a lagoon that forms when land erodes and sinks below the ocean surface.

In the summers of 2020 and 2021, researchers recorded 54 female great hammerhead sharks (Sphyrna mokarran) and one whose sex could not be determined at the two atolls, which are 9 miles (15 kilometers) apart.

They noted that more than half of the sharks were seasonal residents, meaning they spent up to six days a month there, for up to five months. The findings were published Tuesday (Aug. 29) in the journal Frontiers in Marine Science.

Related: Critically endangered hammerhead shark found dead on US beach was pregnant with 40 pups

Female sharks in the vicinity of Rangiroa atoll mostly gathered in a spot called "hammerhead plateau" —  an area 150 to 200 feet (45 to 60 meters) deep, according to the study. "They were mainly sighted roving around the bottom of the plateau, independently from one another," the researchers wrote.

Great hammerhead sharks are a solitary species, so the high number of females sighted at the same time around Rangiroa and Tikehau atolls indicates the area is an aggregation site, according to the study. The sharks likely have no relationship to each other but are drawn there by external factors that appear to be linked to the lunar cycle and the presence of ocellated eagle rays (Aetobatus ocellatus), the study found.

The number of sharks peaked in the days shortly before and after a full moon during both summers — perhaps because the increased moonlight enhanced their ability to hunt around the atolls at night, the researchers suggested. The sharks may also have responded to changes in Earth's geomagnetic field as the moon waxes and wanes, they posited.

Large gatherings of great hammerheads in the area coincided with high numbers of ocellate eagle rays entering the lagoons to reproduce. Sharks prey on these rays, whose mating season is "a predictable event that sharks could try to intercept," the researchers wrote.

Increased water temperature after the winter months may also lure sharks to the Tuamotu archipelago, the scientists added.

The researchers compared their observations with long-term data collected on the atolls, which revealed that some sharks have been returning every summer for 12 years. The team identified an additional 30 male and female sharks from these records and found that males were primarily sighted from August to October, rather than during the summer.

Segregation between males and females has previously been reported for scalloped hammerhead sharks (Sphyrna lewini), the researchers noted, but not for great hammerheads. The researchers' findings suggest that males remain at a distance from the sites occupied by females during the austral summer, which could be linked to their breeding period.

"Lagoons and their protected warm-shallow-coastal waters are known to serve as nursery areas for various shark species," the researchers wrote. While they could not confirm this in the new study, further investigation is underway to determine whether Rangiroa and Tikehau atolls provide nursery grounds for great hammerhead sharks, they added.

Coastal waters around Florida have reached alarming temperatures of 95 degrees Fahrenheit (35 degrees Celsius) with no sign of cooling off anytime soon, experts say.

The Sunshine State is in the midst of its hottest year in modern history, with temperatures over land averaging in the mid 90s F (35 C) — 3 to 5 F (1.7 to 2.8 C) above normal for this time of year. Ocean waters have absorbed much of this heat, causing sea temperatures to soar to record highs, which could spell trouble for marine ecosystems and strengthen storms and hurricanes.

"It's an astounding, prolonged heat wave even for a place that's no stranger to sultry weather," Brian McNoldy, a senior research associate at the University of Miami's School of Marine, Atmospheric, and Earth Science, told the Washington Post. "It's not something we like to see near land simply because it would allow a storm to maintain a high intensity right up to landfall or rapidly intensify as it approaches landfall." 

Related: Heat waves are hitting the deep ocean floor, with potentially catastrophic results 

The marine heat wave has hit at a time when the water is already warm, "bringing it up to bona fide bathtub conditions that we rarely see," he added.

Waters off Florida typically reach temperatures in the high 80s F (31 C) in July, said Jeff Berardelli, chief meteorologist and climate specialist at the television station WFLA-TV in Tampa. But temperatures this year are "boiling," he wrote on Twitter on Monday (July 10). 

The current bath-like conditions are consistent with a "severe" marine heat wave, according to the National Oceanic and Atmospheric Administration (NOAA). The agency defines marine heat waves as "prolonged periods of anomalously high sea surface temperature" that can impact "a broad range of marine life."

This includes coral bleaching, as reefs are "extremely sensitive to slight changes (just a few degrees) in water [temperature]," Berardelli wrote. NOAA's Coral Reef Watch has designted an "Alert Level 1" area off the coast of Florida — the second-highest warning on the scale — with "significant bleaching likely."

The spike in ocean heat in Florida is partly attributable to unusually warm waters in the Gulf of Mexico and to record-breaking sea surface temperatures worldwide. "Very, very light" and "inconsistent" winds over the state have also played a role, Berardelli noted.

"We have a very off weather pattern this summer, and sea surface [temperatures] respond to that," he wrote. While "a nice breeze" typically sweeps over Florida from the southeast this time of year, the state has seen near-windless conditions — and when there is wind, it has brought warmer air from the Gulf of Mexico in the west, Berardelli added.

These conditions mean there has been little to no mixing of the sun-exposed top layer of water with colder waters below.

Another factor contributing to the marine heat wave could be low rainfall over the Floridian peninsula, which usually acts to cool the ocean surface, Berardelli wrote.

The unprecedented water temperatures are intensifying the heat wave on land, which is predicted to rage on for at least another week. Increased ocean warmth raises humidity and keeps air temperatures high during the night. As a result, the state has recorded heat indexes — which factor in humidity to measure how hot the air feels — topping 110 F (43 C).

In June, NOAA reported that 40% of the world's oceans were facing marine heat waves, and this record-breaking percentage is predicted to increase to 50% by September. The effects are tied to climate change compounded by an ongoing El Niño event, with oceans absorbing 90% of the extra heat in the climate system. 

Some sharks can "walk," and researchers recently discovered how one of these unusual shark species practice taking baby steps. They begin when they're newly hatched, and a hatchling's walk is no different from that of older juveniles.

When the tide near a coral reef goes out, a small species of carpet shark is often left behind. When stranded in shallow tide pools with dwindling oxygen levels and rising temperatures — or worse, beached on hot slabs of exposed reef — most aquatic species wouldn't stand a chance. But the epaulette shark (Hemiscyllium ocellatum) can hold its breath for hours and tolerate a range of temperatures. And in a pinch, it can walk. 

"At low tide, when the reef is exposed, you can see them out there walking on the reef," said Marianne E. Porter, an associate professor at Florida Atlantic University who studies the mechanical structures and motion of sharks. She told Live Science that  these hardy little sharks can walk on land and underwater, flopping across substrate on four paddle-shaped fins for more than 90 feet (27 meters) until they find a suitable nook where they can wait out the tide. 

It's one of nature's most distinctive survival strategies, but few studies have examined the physics behind epaulette shark locomotion and gait. Now, a new study in the journal Integrative and Comparative Biology is the first to describe the mechanics of how newly hatched epaulette sharks walk.

The findings may ultimately help scientists understand how other aquatic species will tolerate climate change-related stresses, such as rising carbon dioxide levels. 

"Epaulette sharks live at the extremes," said Porter, lead author of the study. "If we want to learn what happens to animals under the extreme conditions of climate change, looking at animals already living under these conditions — and understanding how they move and cope — may be the first step."

Related: 'Walking sharks' caught on video, astound scientists

Bloated baby sharks

Both Porter and study co-author Jodie Rummer, a professor of marine biology at James Cook University in Australia, had been studying epaulette sharks for years, but they were frustrated to discover that very little information existed on how the carpet sharks actually walk. The most recent study to examine epaulette shark locomotion was published in the late 1990s and focused exclusively on mature sharks. The question of how juvenile and baby sharks walk had never been addressed in the scientific literature.

Porter and Rummer suspected that baby sharks would walk differently than older juveniles and adults did. Epaulette sharks are born bloated, their bellies distended by a yolk sac that fulfills all of their nutritional needs for about one month until they are mature enough to feed on small fish and worms. Their baby fat then rolls off, giving way to the familiar spindle shape of an adult shark. 

"Shape generally impacts the way we move," Porter said. "Human babies walk differently to balance their giant heads, and we assumed that baby sharks would wiggle their bodies and move their fins differently to accommodate their giant bellies."

But after examining multiple videos of young sharks walking and swimming, the researchers were surprised to discover that all young sharks, from newly hatched babies to juveniles that were free of the yolk sacs, appeared to move in the same manner. This observation held across several key metrics, including speed, frequency of tail beating, body bending and fin rotation.   

"I really thought baby sharks would move differently," Porter said. "But in science, we take our best guesses based on the available evidence, and our hypothesis turned out to be wrong."

Beyond walking sharks

It is unclear why baby sharks don't adopt gaits better suited to their bulbous bellies. One possible explanation is that gravity plays a role. The recent study only examined sharks walking underwater, where the yolk sac's bulk does little to hinder movement. In future studies, Porter hopes to look at whether baby sharks adjust their gaits on land to account for the extra weight.

Further research into epaulette shark locomotion also may be useful for evolutionary biologists who study how animals transitioned from water to land, as well as biomechanics researchers who, like Porter, study how fins and feet interact with surfaces and how animals account for gravity and body shape when moving through different environments.

Meanwhile, epaulette sharks are emerging as models for scientists who study how marine fish adapt to changing oceans. Studying how these unique sharks walk to safety may ultimately lead to a better understanding of how other species move within — and away from — challenging environmental conditions, including those associated with climate change. 

"From an evolutionary perspective, a climate change perspective and even a basic physiological perspective, there's a lot we can learn from epaulette sharks," Porter said.

Originally published on Live Science.

Indo-Pacific bottlenose dolphins take their skin care seriously — in fact, the marine mammals medicate their skin by rubbing up against certain types of corals and sponges, which produce compounds that may help guard the dolphins' skin against infection.

Scientists first saw these dolphins scraping their slippery skin against corals about 13 years ago, in the Red Sea off the coast of Egypt. It was then that a team of researchers — including Angela Ziltener, a wildlife biologist at the University of Zurich — spotted the dolphins gliding toward and nuzzling against a bush-like coral species known as gorgonian coral (Rumphella aggregata). 

Divers had anecdotally observed this behavior in the past, but it hadn't yet been studied, Ziltener and her collaborator Gertrud Morlock, an analytical chemist and food scientist at Justus Liebig University Giessen in Germany, told Live Science in a joint statement. 

The researchers suspected that the dolphins might use the corals to self-medicate, since gorgonian coral is known to excrete mucus with antimicrobial properties. As the scientists continued to observe the dolphins, the team noticed that the animals also rubbed their bodies against leather corals in the genus Sarcophyton, and a genus of sponges called Ircinia. Like the gorgonian coral, these other invertebrate organisms are known to produce bioactive substances, although how those substances might benefit dolphins was unknown.  

Related: These dolphins taught each other to moonwalk — but it was just a fad 

Now, in a new study published Thursday (May 19) in the journal iScience, scientists have pinpointed more than a dozen bioactive compounds that are produced by these corals and sponges and which likely help maintain dolphins' skin health. By regularly coating their silver-gray bodies in these compounds, the dolphins may prevent and treat skin infections, as well as generally maintain their skin microbiome — the community of microorganisms living on their flesh.

Since they first visited the Red Sea in 2009, the research team has repeatedly returned to the site to scuba dive amongst a pod of about 360 Indo-Pacific bottlenose dolphins (Tursiops aduncus) that live near the coastal Egyptian cities of Hurghada and El Gouna. Through a combination of boat-based surveys from the sea surface and close-up underwater observations, the team came to recognize the dolphins' typical behavior patterns. 

The dolphins often queued up behind one another, seemingly waiting their turn to slide through the branches of a gorgonian coral or rub their heads against a hard Ircinia sponge, the team observed. Once rubbed, these invertebrates released mucus that then transferred to the dolphins' skin. When the dolphins rubbed against a coral or sponge especially vigorously, their skin sometimes became stained a "striking" yellowish or greenish color, due to the compounds excreted by the invertebrates, the authors wrote in their report. 

The youngest dolphins, less than 1 year old, seemed to observe as the mature dolphins rubbed against the corals and sponges; then, in time, these younger dolphins tried out the behavior themselves, first by lightly touching the corals with part of their body and then swiftly swimming away. These observations hint that each generation of dolphins picks up the coral-rubbing behavior through social learning, rather than knowing how to do so innately, the authors wrote.

In addition to collecting photos and videos of the dolphins, the researchers sampled small pieces of the animals' preferred corals and sponges. Back in the lab, Morlock and her team carefully separated each sample into its component compounds and determined their identities using a technique called high-resolution mass spectrometry. 

Related: Amazing video shows a mom chimp medicating her child's wound with insects

The chemists also assessed the bioactive properties of each compound, by testing whether a given substance effectively killed bacteria or interfered with the activity of specific enzymes, for example.

These analyses revealed 17 bioactive substances, 10 of which showed antibacterial effects against both gram-positive and gram-negative bacteria; these two groups of bacteria differ in the structure of their outer cell walls and membranes and thus react differently to antibacterial compounds. 

Some of the substances acted as antioxidants, while others showed estrogen-like effects. These hormone-like compounds were specifically produced by the leather coral and may help to maintain dolphins' skin hydration and elasticity, Ziltener and Morlock told Live Science. The leather coral also produced small amounts of toxic substances that could help eliminate parasites on the skin surface, they said. 

One limitation of the study is that the biological effects of these compounds were assessed in the lab, not on dolphin skin, the authors told Live Science. In theory, these compounds should have some effect when the dolphins shimmy against them on the reef, but based on their current research, the team can't determine exactly how the substances regulate the skin microbiome or which specific infections they treat most effectively. 

Another limitation of the study is that the researchers didn't examine other Red Sea corals, just the species the dolphins preferred, said Luke Rendell, a biologist at the University of St. Andrews in Scotland, who was not involved in the study. 

"There isn’t evidence that the corals used for rubbing are special in their chemical properties," Rendell told Live Science in an email. "The case would be strengthened if the study also showed that non-selected corals didn’t have these properties." Such evidence would bolster the idea that the dolphins specifically seek out the medicinal corals and sponges for their healing properties.

That said, the research does begin to connect the dots between the dolphins' affinity for specific corals and the medicinal properties of said corals. 

"Based on the behavioral observations and the profound analytical data obtained, we dared to hypothesize that the bioactive molecules can have an effect upon skin contact," Ziltener and Morlock told Live Science. Such self-medication has never been documented in a dolphin, whale or porpoise, making this study a fascinating first.

Originally published on Live Science. 

A tangled mass of what looked like discarded yellow rope recently washed up on a beach in Texas. But this peculiar knotty pile wasn't garbage. It was a colorful sea whip — a type of soft, flexible coral. 

Rebekah Claussen, a National Park Service (NPS) guide at the Padre Island National Seashore near the Gulf of Mexico, found one of these "rope balls" partly buried in the sand, and the park shared her photo on Facebook on Feb. 1.

Sea whips can be red, yellow, orange, violet, lavender or purple, according to the Marine Species Identification Portal. However, "we mostly see the yellow and red varieties washing up on our beaches," NPS representatives wrote in the Facebook post.

Related: 13 bizarre things that washed up on beaches

The term "sea whip" can refer to several genera of soft corals in the order Gorgonacea, but the species that washes up in North American coastal regions is a colorful sea whip (Leptogorgia virgulata). Sea whips' vibrant color comes from colonies of polyps — tiny, soft-bodied animals with eight tentacles forming a ring around their mouths. When these colonies cluster together they secrete proteins that form a dark-colored skeleton, which branches into whiplike stalks measuring up to 3 feet (0.9 meters) tall, according to the Tybee Island Marine Science Center (TIMSC) in Georgia.

Colorful sea whips live close to the shore, and L. virgulata can be found in waters as far north as New Jersey and as far south as the Gulf of Mexico, according to TIMSC. Polyps feed on plankton, and sea whips typically cling to ledges made of rock and limestone at depths between 10 and 66 feet (3 and 20 m), according to the Smithsonian Marine Station at Fort Pierce in Florida.

But when sea whips are torn from their ocean habitats and deposited on beaches, they're easy to mistake for discarded fishing line, nets or cable. Several people who commented on the Facebook post mentioned that they had encountered sea whips while cleaning up a local beach, and they mistakenly collected it, thinking that it was garbage.

"Generally speaking, most of it is dead when it washes up," Claussen told Live Science in an email. "To my knowledge, the reason that the coral has washed up is that it has broken off and therefore no longer alive. I'm not sure that you would be able to tell even if it was alive," she added. "We recommend just leaving the sea whip on the beach because it is natural and will decompose and help the island," Claussen said.  

"So the next time you're out for a stroll on the beach, look for the sea whip and remember, it's not trash!" NPS representatives wrote in the post.

Originally published on Live Science.

Diving hundreds of feet below the surface of the ocean off the coast of the Philippines, scientists came across a bubbling hotspot of carbon dioxide. And this newly discovered vent might help us predict how coral reefs will deal with climate change, according to a new study. 

Bayani Cardenas, a professor in the Department of Geological Sciences at The University of Texas at Austin, accidentally discovered this carbon dioxide fountain while researching the effect of groundwater runoff into the ocean environment in the Philippines's Verde Island Passage.

This strait that runs between the Luzon and Mindoro islands, connecting the South China Sea with the Tayabas Bay, is busy on its surface, serving as a prominent shipping route. It's also busy below the surface, where it harbors one of the most diverse marine ecosystems in the world. And the reefs in this passage, unlike bleached reefs elsewhere, are thriving, according to a statement from The University of Texas.

The researchers named the new hotspot Soda Springs and said that it could have been releasing these bubbles for decades or even millennia.

Related: Photos: Hawaii's New Underwater Volcano

Soda Springs is a result of an underwater volcano, which vents gas and acidic water through cracks in the ocean floor. The researchers found carbon dioxide concentrations as high as 95,000 parts per million (ppm) near the springs, which is over 200 times the concentration present in the atmosphere, according to the statement.

The levels quickly fell as the gas flowed into the massive ocean, but the seafloor released enough gas to create elevated levels (400 to 600 ppm) and enough acidic water to lower the pH for the nearby coastline. This might thus be an ideal spot for studying how other coral reefs around the world may cope with climate change as it brings more carbon dioxide into their environments, Cardenes said in the statement.

What's more, by tracing levels of radon-222, a naturally occurring radioactive isotope found in groundwater local to the area, the team discovered hotspots on the seafloor where groundwater was being discharged into the ocean. "Groundwater flow from land to sea could have important coastal impacts, but it is usually unrecognized," the authors wrote in the study. "Delicate reefs may be particularly sensitive to groundwater inputs."

The researchers found that groundwater and seawater appeared in different relative amounts in different areas of Soda Springs. This variable mixing means that "the groundwater flow could be contributing to the evolution and functioning of the ecosystem," the authors wrote.

However, the presence of these passageways might also mean that there is a way for pollutants from the island to make it into the coral reefs, Cardenes said in the statement. In the Philippines, where coastal development has surged, people are using septic tanks instead of modern sewage systems, which can easily pump waste into the reefs, Cardenes said.

It's not clear how these reefs thrive in a carbon-dioxide-rich environment, but then again, not much is known about this area. "It's really a big part of the ocean that is left unexplored," Cardenes said in the statement. "It's too shallow for remotely operated vehicles and is too deep for regular divers."

The findings were published on Jan. 3 in the journal Geophysical Research Letters.

• Hidden Undersea Mountains Uncovered with Satellites (Photos)
• 5 Places Already Feeling the Effects of Climate Change
• 5 Ways Climate Change Will Affect Your Health

Originally published on Live Science.

Climate change is killing the world's coral reefs. But it's not the only factor turning them into white, dead husks. According to a new study, all the chemicals humans are dumping into the ocean are making it easier for the hotter weather to do its deadly work.

The research paper, published online Monday (July 15) in the journal Marine Biology, is based on data collected over three decades from the Looe Key Sanctuary Preservation Area in the Florida Keys. Coral coverage declined from 33% in 1984 to just 6% in 2008 in that sanctuary. Even as temperatures have trended upward globally, average local temperatures didn't change much during the study period. This allowed researchers to disentangle a number of different problems sickening (or "bleaching") the reef.

First, the researchers found, bleaching events — due to the loss of algae called zooxanthellae that give coral their color — did tend to occur once water temperatures had spiked above a threshold of 86.9 degrees Fahrenheit (30.5 degrees Celsius). Such a spike occurred 15 times in the period covered in the study (between 1984 and 2014). [In Photos: Diving in a Twilight Coral Reef]

Second, and significantly, the ratio of nitrogen and phosphorus in the water turned out to be a key factor in determining when and to what extent coral bleached. When Florida rains caused agricultural fertilizers containing nitrogen and phosphorous to run off into the ocean, coral death was more common. Those increased nutrients in the water caused algae blooms, which in turn seemed to predict mass coral deaths. Nitrogen, in particular, turned out to be the most important factor related to mass coral bleaching.

This study didn't examine the mechanism by which nitogren leads to bleaching, said Brian Lapointe, lead author of the paper and a researcher at the Harbor Branch of Florida Atlantic University. But other research by scientists studying the Great Barrier Reef has shown why and how it happens, he told Live Science.

As the nitrogen-phosphorous balance in the ocean gets out of whack, certain membranes in the coral start to break down. The coral can't get enough phosphorous, he said, leading to "phosphorous limitation and eventual starvation."

"It degrades the ability of these organisms to survive high light and high temperatures," Lapointe said. "It actually reduces their light and temperature thresholds."

A great deal of the effect of these added nutrients could be mitigated by improved water-treatment plants, the researchers noted. Most of the nitrogen in runoff doesn't pour right off the land into the sea during rainstorms, but instead passes through water-treatment plants that fail to remove the chemical.

In Dutch-controlled regions of the Caribbean, the researchers noted in a statement, improved sewage-treatment plants do pull nitrogen out of the water. And in those places, coral reefs are faring better than they are off the coast of Florida, the scientists pointed out.

Coral isn't just a necessary foundation of thriving marine ecosystems, the researchers said in their statement. Reefs also directly contribute $8.5 billion each year and 70,400 jobs to the Florida economy, according to the Florida Keys National Marine Sanctuary.

"Citing climate change as the exclusive cause of coral reef demise worldwide misses the critical point that water quality plays a role, too," James Porter, an emeritus professor of ecology at the University of Georgia and a co-author of the paper, said in the statement. "While there is little that communities living near coral reefs can do to stop global warming, there is a lot they can do to reduce nitrogen runoff. Our study shows that the fight to preserve coral reefs requires local, not just global, action."

• Image Gallery: Great Barrier Reef Through Time
• Pretty in Pink: Photos of Bubblegum Coral
• Photos: The Secret Lives of Corals

Originally published on Live Science.

What's the story behind mysterious "halos" of bare sand that surround coral reefs?

When reefs are healthy an unusual phenomenon occurs: a perimeter of bare sand forms around the corals. These so-called halos, or bright circles of sand that are devoid of vegetation are visible to satellites miles above Earth.

But until now, scientists didn’t fully understand exactly how they formed, and why some were bigger than others. Now, two new studies may help answer the mystery of how halos take shape and what conditions make them grow. [In Photos: Diving in a Twilight Coral Reef]

Mysterious halos

Halos occur when fish and invertebrate inhabitants eat algae and seagrass growing near the reef. Over time, all vegetation in this zone is cleared away; these empty stretches of sand can measure from hundreds of square feet to hundreds of thousands of square feet, and create a footprint around the reef that's visible from space.

Researchers in the two studies recently took a closer look at these halos. Not only did they observe reef animal activity that unexpectedly extended the perimeters of the halos, the researchers also determined that the halos could be used as barometers for reef health. Learning how to interpret halos from satellite images could help scientists monitor hard-to-access reefs, the study authors reported.

In one study, published online today (April 24) in the journal Frontiers in Ecology and Evolution, the scientists found complicated species interactions shaped halos in Australia's Great Barrier Reef.

Remote underwater video camera traps revealed that herbivorous fish weren't the only reef dwellers enlarging halos — fish that hunted burrowing invertebrates played a part as well. By digging in the sand for their prey, these carnivorous fish nudged sand-dwelling algae farther away from the reef and widened the halos' boundaries, the researchers reported.

A pattern emerges

More clues about the halos emerged when the scientists examined high-resolution satellite images of coral reefs, publishing their findings today (April 24) in the journal Proceedings of the Royal Society B. They reviewed 1,372 reefs throughout the Great Barrier Reef, measuring features in 214 reefs; each of these contained hundreds to thousands of small, isolated coral platforms that were capable of being surrounded by a halo.

The study authors also conducted underwater surveys with camera traps at 22 halo locations, for three weeks.

The scientists were then able to directly compare halo patterns in waters where fishing was permitted — which would therefore have fewer predatory fish — and in waters that were protected, where predators would be plentiful.

The study authors suspected that in predator-rich protected waters, herbivorous fish would be more cautious and would graze close to the coral reef; the halos would therefore be smaller. In reefs that were open to fishing and had fewer predators, the scientists expected that grazing fish would be bolder, and that halos would reach farther from the reef, or would even be overgrown and disappear. But halos in both protected and unprotected waters turned out to be pretty much the same size, the study authors reported.

However, they discovered that halos were more likely to form in protected marine areas, "especially the older protected areas where predator populations have had longer to recover from previous fishing," lead study author Elizabeth Madin, an assistant research professor with the Hawaii Institute of Marine Biology at the University of Hawaii at Manoa, told Live Science.

That demonstrated to the researchers that halos could be a reliable indicator of stability in a reef's predator-prey populations, "which is an indicator of a healthy reef ecosystem," Madin said.

Their findings present new evidence showing how laws prohibiting fishing near reef communities can improve reef health, according to the study.

Coral reefs are typically monitored by divers that count species and evaluate the condition of corals and other life. However because halos are visible from space, satellite images could complement those surveys by providing snapshots of how reef halos change over time, Madin explained.

They also offer a glimpse at reefs that are inaccessible to divers, she added.

"We can look at them almost anywhere from satellite imagery, so this will give us a much broader view than what we could ever hope to do with the traditional monitoring methods. It would complement and scale what we can see," Madin said.

• Image Gallery: Great Barrier Reef Through Time
• Pretty in Pink: Photos of Bubblegum Coral
• Photos: The Secret Lives of Corals

Originally published on Live Science.

The Coral Triangle is a vast network of coral reefs that dot the waters surrounding the Philippines, Indonesia, Malaysia, Papua New Guinea, the Solomon Islands and Timor-Leste.

Also known as "the Amazon of the ocean," this expansive underwater ecosystem in Southeast Asia is a hotspot for marine biodiversity, hosting 30 percent of the world's coral reefs that span 2.3 million square miles (6 million square kilometers). From humpback whales to humphead wrasses, a wide variety of sea creatures survive and thrive along the reefs in the Coral Triangle.

Biodiversity hotspot

"If you go to a place in the Coral Triangle — like the Verde Island Passage or Bali — there's so much microhabitat diversity," said Luiz Rocha, a coral reef scientist at the California Academy of Sciences. "You can go 100 yards [90 meters] from one reef to another, and the reef composition will be completely different."

The region is home to more than 500 species of reef-building corals, which have adapted to an array of habitats. Some corals, like those Rocha and other scientists at the California Academy of Sciences study, are adapted to live at greater depths and in cooler waters. Other corals in the region are adapted to muddy, sediment-rich waters, as opposed to the crystal-clear conditions most corals prefer, according the London Natural History Museum.

Nearly a third of the world's coral-reef fish species and six of the world's seven species of sea turtle call the Coral Triangle home, according to the World Wildlife Fund. Other marine creatures — such as dugongs, damselfish, manta rays and throngs of invertebrates — inhabit parts of the Coral Triangle.

There are many theories as to why reefs in this part of the world are so successful. Here are a few that may explain the abundance of life in the Coral Triangle:

• Center of origin hypothesis: From volcanic islands with rocky shores to white sand beaches to mangrove forests, the Coral Triangle consists of a wide range of habitats. Scientists suspect that the diversity of landscapes contributes to the diversity of species in the region because these species have been forced to adapt to the geographically complex reef system.
• Center of accumulation hypothesis: Prevailing currents pour water into the Coral Triangle. The center of accumulation hypothesis suggests that many species originate in isolated archipelagos in the Indian and Pacific oceans, such as Hawaii or the Maldives, and then are swept to the Coral Triangle by those currents. Once in the Coral Triangle, these species mix and mingle with species already living in the region, and eventually form new species.
• Center of overlap hypothesis: The Coral Triangle sits between the Indian and Pacific oceans. Marine species from both bodies of water colonize parts of the reef system where the ocean basins overlap, increasing the number of species found in the region. "There are parts of Indonesia that have Indian Ocean fauna. There are parts of Indonesia that have Pacific Ocean fauna, and there are parts that have both," said Paul Barber, a marine scientist with the University of California, Los Angeles. "It's the overlap of these two faunas that create such a diverse ecosystem."
• Center of survival hypothesis: As geographic area increases, the risk of extinction decreases. If a species inhabits a large area, there's less of a chance the organism will go extinct if something happens to one part of the reef where that species lives. "Because the Coral Triangle is [the] largest region of coral reef in world, it's going to have [the] lowest extinction rates in the world," Barber said.

Unlike the Great Barrier Reef or the Caribbean Reef, which are more exposed and have changed significantly over time, the Coral Triangle is "a very stable region, even through geologic time," Rocha said. Research published in October 2018 in the journal Proceedings of the Royal Society B suggested that the persistence of these stable conditions over the last 30 million years may have given rise to the Coral Triangle's biodiversity.

Rocha is quick to note that "all of these hypotheses could have contributed to and influenced" the region's high biodiversity.

Reefing the benefits

With roughly 264 million people strung along the island chain, Indonesia is the fourth most populous country in the world, according to the World Bank. In total, more than 360 million people live around the Coral Triangle, 100 million of which rely on the reefs for their livelihood, according to a 2014 report by the Coral Triangle Initiative. One-third of the population rely on seafood as their primary source of protein, fishing grouper, tuna and other predatory fish species, Barber said.

Healthy reefs also provide other benefits to the islands they encompass, acting as natural barriers that soften the blow from typhoons, storm-generated waves and even tsunamis. A June 2018 study in the journal Nature Communications revealed that damage to coastal communities in the Coral Triangle caused by flooding events would nearly double without the coral reefs. Additionally, without these reefs, countries like Malaysia, Indonesia and the Philippines would see the costs related to flooding events triple; if protected, the reefs that ring these countries could save, on average, more than $400 million each year.

Colorful reefs also draw tourists from around the world and provide an economic boost to exotic locales like Bali in Indonesia and Sipadan Island in Malaysia, which are known for their pristine scuba-diving conditions.

Paradise in peril

These prolific ecosystems are incredibly fragile. Habitat destruction, pollution and climate change are threatening coral reefs around the world, and the Coral Triangle is no exception.

Much of the damage to reefs in the Coral Triangle is caused by poor fishing practices, Rocha said. Often, locals will overfish, drag nets that damage fragile corals and leave fishing equipment to float around in the water.

Large predators, like sharks and groupers, are critical to the health of the reef, often keeping populations of coral-munching fish in check. When large, predatory fish are sustainably caught, the reef can rebound. Often, though, the Coral Triangle's largest predators are pulled from the reef in high numbers, shrinking their populations and allowing destructive fish populations to weaken the coral reef ecosystem.

Barber warned that the collapse of the fishing industry in the Coral Triangle due to overfishing would devastate the local countries and could eventually impact the entire world, as impoverished communities sought food elsewhere. If these regions are overfished, "it's not like they [communities] can just ramp up animal husbandry to replace that missing seafood," he said.

Yet another threat reefs face is plastic pollution. Small pieces of plastic are easily consumed by animals that live in the reef, but the presence of this litter acts as a threat multiplier. In some cases, plastics that pollute reefs in the Coral Triangle have acted as vectors for disease, spreading contagions like so-called white syndrome from sick to healthy corals, as reported in a 2018 study in the journal Science.

Because of climate change, reefs like the Coral Triangle will increasingly face bleaching events. As corals are exposed to rising water temperatures, they become stressed and expel the symbiotic algae that live inside them. This leaves the coral colorless, or bleached, and unable to feed themselves.

In the long term, ocean acidification will also cause problems for reefs. The ocean becomes more acidic as it absorbs carbon dioxide from the atmosphere. The calcium carbonate skeletons of most coral species aren't built to withstand that acidity, and so they slowly dissolve.

But there's still hope, insisted Rocha. The Coral Triangle is "more resilient against climate change because of the complexity in that region," he said. Because the Coral Triangle is less exposed than places like the Great Barrier Reef, there's a chance the Coral Triangle can withstand some of the more dire consequences of climate change.

Further reading:

• Learn more about what the Coral Triangle Center is doing to help conserve and protect the Coral Triangle.
• Read more about the Coral Triangle from the World Wildlife Fund.
• Learn more about the basic biology of coral reefs from the Scripps Institute of Oceanography.

Once vibrantly colored and teeming with life, many coral reefs around the planet are now bleached and barren, thanks to a condition called coral bleaching. Their color drained, bleached reefs stand like skeletons along the world's coastlines, from Australia and Madagascar to the Persian Gulf and the Caribbean Sea.

But coral bleaching is much more than an aesthetic loss. It is an environmental indicator: an omen of starving animals, a failing ocean ecosystem and a devastating change in global climate. Rising ocean temperatures are the fundamental cause. But before we can understand why these beautiful coral ecosystems are now at risk, we have to understand how they got their radiant color in the first place.

How do corals get their color?

Coral reefs are made up of polyps, small, colorless animals that have a sac-like body with a mouth-like opening and a crown of stinging tentacles. A coral reef consists of many individual polyps functioning together as one unit.

The polyps themselves are transparent. Coral reefs get their color from the tiny creatures living inside the polyps: algae called zooxanthellae.

Coral and zooxanthellae enjoy a mutually beneficial partnership, known as symbiosis. Coral provides the algae with shelter, access to sunlight and other resources needed for photosynthesis. The algae, in turn, share the nutrients produced by photosynthesis with the coral. As much as 90 percent of the nutrients that algae produce are transferred to their coral hosts, according to the National Oceanic and Atmospheric Administration (NOAA).

Why do corals bleach?

Under environmental stress, the intricate algae-coral partnership becomes unhinged. Factors such as temperature changes, pollution and overfishing can destabilize the relationship and cause the coral to expel the algae. Once the algae are gone, the coral's bright white calcium-carbonate exoskeleton is visible through its transparent tissue, hence the name coral bleaching.

Rising sea temperatures brought on by global warming have become the greatest danger to coral reefs, according to NOAA. Temperature spikes of only 1.8 to 3.6 degrees Fahrenheit (1-2 degrees Celsius) can trigger mass bleaching events that affect tens to hundreds of miles of coral reef. This type of heat stress affected 70 percent of the world's coral reefs between 2014 and 2017.

Coral bleaching happens gradually, said Ruben Torres, a marine scientist and the founder of Reef Check Dominican Republic, a nonprofit ocean-conservation group. As water temperature rises above the coral's comfort zone, the algae begin to leave, and the coral grows paler until all of the algae are gone.

"Once algae are gone, they [the corals] lose their source of energy," Torres said. "They are basically starving to death."

Bleached coral are still alive, but without the algae, the coral are vulnerable. They have less energy and are more prone to disease. If the water temperature remains high for days or weeks, according to NOAA, bleached coral will begin to die. If the water temperature goes back to normal, the coral can eventually regain algae and their color, but even the fastest growing corals need 10 to 15 years to fully recover, according to a 2013 study published in the journal Science.

"We used to think bleaching happened once a century," said Dave Vaughan, a biologist at the Elizabeth Moore International Center for Coral Reef Research & Restoration in Florida. "Corals would have 100 years to recuperate," he said. "But then, there was one bleaching in the '70s, two in the '80s and now 12 in the last 14 years."

The rise in coral bleaching parallels increases in atmospheric and ocean temperatures. Between 2016 and 2017 — the two hottest years on record, according to NASA — half of the Great Barrier Reef died in bleaching events set off by high sea temperatures, a study published in 2018 in the journal Nature reported. [Image Gallery: Great Barrier Reef Through Time]

A sliver of hope

The outlook for corals is grim but not completely hopeless. Natural reefs will not last through the 21st century if climate change continues undeterred, according a 2017 United Nations assessment. Because plans for lowering global carbon dioxide emissions are not taking effect at a rate fast enough to save reefs, some scientists are going a step further to preserve coral communities by giving them a boost.

Vaughan and his colleagues explore coral reefs that have experienced bleaching to find the survivors. The researchers then raise those particular corals in the lab to better understand what makes them more resilient. Vaughan said he hopes to grow coral that can withstand today's conditions — and tomorrow's warmer conditions — and then plant them on natural reefs to make the reefs hardier.

"Some corals aren't affected or bounce back faster so they don't get disease or starve to death," Vaughan said. "If we make more of those, we make a more resilient reef."

Other researchers are busy crossbreeding different strains of resistant corals to develop what are known as supercorals, which have an even better chance at surviving climate change. Both types of resilient coral have been grown in nurseries and planted back in the ocean successfully, but only on an experimental level. Now, scientists are aiming to plant at a much larger scale, Vaughan said. Reef restoration is desperately needed all over the world, but it won't come cheap, he said.

The first few years of growing and planting coral have a high cost and a low output. It can cost $25 to $200 to grow and plant a single coral, Vaughan said. A reef the size of a football field contains upward of 10,000 individual corals; that's $2 million to restore a small reef.

After four to five years, however, production increases and the price per coral falls. Today, Vaughan's lab grows and plants each coral for $10, and he said, at scale, that number could fall to $2 per coral, each critter costing the same as a cup of coffee.

So, what's the cost of restoring the world's reefs? Vaughan has run the numbers (it's in the billions), but he said the better question is, "What's the cost if we don't?"

Are coral reefs really worth the trouble?

No matter how much these rescue attempts cost, marine biologists argue that saving coral reefs is essential, for both biological and economic reasons.

Coral reefs cover only 1 percent of the ocean floor, but the Smithsonian estimates that as much as 25 percent of marine life depends on these reefs for food and shelter. In other words, coral reefs make up the backbone of the ocean's most diverse ecosystem. So, although the term "coral bleaching" refers to a phenomenon affecting just one group of closely related species, their deaths devastate an entire habitat.

Humans also have a huge stake in healthy coral reefs. Reef-related tourism is worth $35 billion to the global economy, according to a 2017 study published in the journal Marine Policy.

Reefs also help to protect shorelines, especially with today's increasingly severe tropical storms, preventing as much as $4 billion in flood damages globally every year, according to a recent study in the journal Nature Communications. The demise of these reefs, via bleaching and collapse, would cost the U.S. $100 million a year in additional flood damages, the same study concluded. Countries like Indonesia and the Philippines would be hit even harder, incurring annual damages of more than $600 million.

Saving coral reefs is daunting, but the alternative is cataclysmic, Vaughan said. He's set his sights on planting 1 million corals before he retires. He's planted TKHOWMANY so far. Starting in January 2019, he's taking his reef-restoration efforts global through his Plant a Million Corals effort, in which he travels the world educating and consulting clients on how to restore the reefs near them. As Vaughan sees it, "There is hope."

Further reading:

• See these shocking images from the Coral Reef Image Bank of the devastating effects of coral bleaching.
• Read more about coral bleaching on the Great Barrier Reef, from the Australian Marine Conservation Society.
• Find an overview of the basic biology of coral reefs here from the Scripps Institution of Oceanography.

This past year brought tons of fascinating new information about our planet. But as scientists gaze into their crystal balls, they can see that this year is also sure to contain exciting surprises. Here we take a look at the seven most highly anticipated geophysics and Earth science expeditions, missions and meetings of 2019.

Inspecting Thwaites Glacier for cracks

Next summer, a major expedition will head to West Antarctica's Thwaites Glacier. As part of a $25 million research collaboration between the U.S. National Science Foundation (NSF) and the United Kingdom's Natural Environment Research Council (NERC), more than 100 scientists from around the world will study the giant glacier, which acts something like a cork holding back other enormous ice masses. Should the glacier begin to collapse, these masses could slide into the ocean and melt, contributing to sea level rise. "Satellites show the Thwaites region is changing rapidly," William Easterling, NSF assistant director for Geosciences, said in a statement. "To answer the key questions of how much and how quickly sea level will change requires scientists on the ground with sophisticated equipment collecting the data we need to measure rates of ice-volume or ice-mass change." [Photos of Melt: Glaciers Before and After]

Creating amazing new ice maps

In September 2018, NASA launched the Ice, Cloud and Land Elevation Satellite-2 (ICESat-2), a space-based observatory peering at the poles. The mission measures the changing thickness of individual patches of ice from season to season, and can detect increases and decreases as small as a 0.2 inches (0.5 centimeters). Since its launch, the satellite has been collecting a terabyte of data a day and has already produced one of the most detailed maps of Antarctica's ice. Some initial results appeared at the annual meeting of the American Geophysical Union in December 2018 "and the data looks spectacular," physical geographer Michael MacFerrin of the University of Colorado in Boulder, told LiveScience. ICESat-2 will "help revolutionize our real-time views of ice sheets, sea ice and the polar regions in general," he added. "Folks are really excited to work with this dataset once it's out, and I suspect there will be first papers coming out before the end of this year in 2019."

Drilling into the cause of an earthquake

Off the southwest coast of Japan, deep below the Pacific Ocean, sits the Nankai Trough, an active subduction zone where one plate of the Earth's crust is slipping beneath another. It is one of the most seismically active places on the planet, responsible for the 8.1-magnitude Tōnankai earthquake that rocked Japan in 1944. This year, the Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) began drilling into the fault. It is the "first [expedition] to drill, sample and instrument the earthquake-causing, or seismogenic portion of Earth's crust, where violent, large-scale earthquakes have occurred repeatedly throughout history," according to the mission's website. Rocks collected next year will be analyzed to see how slippery or solid they are, allowing researchers to "understand more about the conditions that might lead to an earthquake on these type of fault," wrote team member John Bedford of the University of Liverpool on the expedition's blog.

Measuring the forest and the trees

On Dec. 8, NASA launched the Global Ecosystem Dynamics Investigation lidar (GEDI) experiment to the International Space Station. The instrument will be mounted on the outside of the station so it can peer down at our planet and produce incredibly detailed 3D observations of Earth's temperate and tropical forests. GEDI will aim to answer several fundamental questions, including how much carbon is stored in trees and how deforestation could affect climate change, according to the mission's website. This will in turn help researchers model how nutrients cycle through the forest ecosystems and, because forest heights affect wind patterns around the globe, more accurately predict weather, according to the GEDI website.

Exploring a buried Antarctic lake

As you read these words, scientists in Antarctica are drilling into a subglacial lake buried 4,000 feet (1,200 meters) beneath the West Antarctic Ice Sheet. Known as Lake Mercer, the body of water is completely disconnected from the rest of the world's ecosystems. Researchers are eager to explore the system and learn more about the organisms that are living there, according to the mission's official website. Once the drill reaches the body of water, "equipment will be lowered into the hole to collect samples, take readings, and photograph a subglacial world never before seen by human eyes," according to the site. [Extreme Life on Earth: 8 Bizarre Creatures]

Learning the history of coral reefs

Coral reefs are beautiful yet endangered underwater habitats. Pollution and ocean acidification — caused when oceans absorb carbon dioxide released into the atmosphere through the burning of fossil fuels — are threatening reefs all over the globe. Beginning in September of next year, a team of researchers will drill into up to 11 locations beneath the oceans around Hawaii, looking to pull up samples from fossilized coral reef systems. These reefs, which will span 500,000 years of recent geologic history, will help answer critical questions about the amount of carbon dioxide in the atmosphere and Earth's temperature during this period, and how coral reefs reacted to and recovered from large-scale changes, according to the mission's website. The expedition, named the Hawaiian Drowned Reefs expedition, is being run by the European Consortium for Ocean Research Drilling (ECORD), an international body that conducts scientific drilling missions.

Exploring the deep biosphere

For the last 10 years, scientists with the Deep Carbon Observatory have been digging into Earth to learn more about what's buried beneath our feet. In December, they announced new findings about the "deep biosphere," a subterranean reservoir of uncatalogued organisms that could dwarf the amount of life on our planet's surface. Next October, at an international conference in Washington, D.C., the organization will highlight its last decade of research and look forward to 10 more years of exciting expeditions. Researchers at the meeting will present information on "the nature and extent of carbon in Earth's core, the nature of the whole Earth carbon cycle and how has it changed over Earth's history, and the mechanisms that govern microbial evolution and dispersal in the deep biosphere," according to its website.

Originally published on Live Science.

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If you listen closely, you can hear little plants harnessing the sun's energy. All you have to do is dive underwater and listen for the faint but distinctive "ping!" that red algae make while carrying out photosynthesis, a new study finds.

Just like plants on land, algae photosynthesize — essentially using the sun's rays to turn molecules of carbon dioxide and water into sugar and oxygen gas. Underwater, those teeny tiny oxygen bubbles rush upward. As these bubbles detach from the plant, they make a short "ping" sound, the researchers found.

"Many such bubbles create a large, distributed sound source over the seafloor," the researchers wrote in the study, published online Oct. 3 in the journal PLOS ONE. These noteworthy pings may help researchers monitor the health of coral reefs covered by these algae, they said. [In Photos: Diving in a Twilight Coral Reef]

The researchers first noticed the pings in Hawaii, when they discerned that healthy, protected reefs were making low-frequency sounds, while damaged reefs seemed to call out in higher-pitched sounds, Hakai Magazine reported.

"We were told the sound was from snapping shrimp, end of story," Simon Freeman, who works with his wife and study co-researcher Lauren Freeman as an oceanographer at the U.S. Naval Undersea Warfare Center in Rhode Island, told Hakai Magazine. "[But] there seemed to be a correlation between the sound and the proportion of algae covering the seafloor."

To learn more, the Freemans and their research team transferred 22 lbs. (10 kilograms) of invasive red algae (Gracilaria salicornia) collected from Hawaii's Kaneohe Bay into a tank filled with seawater. This helped them analyze any sounds the algae made, away from the clamor of the noisy ocean.

The experiment worked; the scientists recorded high-frequency pings, which sounded like the dings they heard from the distressed reefs.

Part of the corals' distress comes from algae that are smothering them, the researchers said. People are to blame for some of these algae spikes, largely because of overfishing of the fish that keep the algae in check, pollution from nutrient runoff and climate-change effects, they said.

Given that high agal cover is a strong indicator that coral reefs are struggling to survive, it's possible that monitoring the sounds of these agal bubbles could be a fast and noninvasive way for scientists to keep tabs on coral reef health, the researchers said.

"Right now, reefs are evaluated visually by divers," Simon Freeman told Hakai Magazine. But this method is expensive and time intensive, so "in the future, it might be possible to quickly listen to a coral reef soundscape, perhaps by using an autonomous vehicle, and evaluate how it may have changed from the previous year."

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Originally published on Live Science.

Coral reefs are large underwater structures composed of the skeletons of colonial marine invertebrates called coral. The coral species that build reefs are known as hermatypic, or "hard," corals because they extract calcium carbonate from seawater to create a hard, durable exoskeleton that protects their soft, sac-like bodies. Other species of corals that are not involved in reef building are known as “soft” corals. These types of corals are flexible organisms often resembling plants and trees and include species such as sea fans and sea whips, according to the Coral Reef Alliance (CORAL), a nonprofit environmental organization.

Each individual coral is referred to as a polyp. Coral polyps live on the calcium carbonate exoskeletons of their ancestors, adding their own exoskeleton to the existing coral structure. As the centuries pass, the coral reef gradually grows, one tiny exoskeleton at a time, until they become massive features of the marine environment.

Corals are found all over the world's oceans, from the Aleutian Islands off the coast of Alaska to the warm tropical waters of the Caribbean Sea. The biggest coral reefs are found in the clear, shallow waters of the tropics and subtropics. The largest of these coral reef systems, the Great Barrier Reef in Australia, is more than 1,500 miles long (2,400 kilometers).

Scientists have explored only about 20 percent of the ocean's floor, according to the National Oceanic and Atmospheric Administration (NOAA). As such, ocean explorers continue to discover previously unknown coral reefs that have likely existed for hundreds of years.

The lives of coral

There are hundreds of different species of coral, according to CORAL. Coral have a dazzling array of shapes and colors, from round, folded brain corals (named for their resemblance to a human brain) to tall, elegant sea whips and sea fans that look like intricate, vibrantly colored trees or plants.

Corals belong to the phylum cnidaria (pronounced ni-DAR-ee-uh), a group that includes jellyfish, anemones, Portuguese man o' war and several other gelatinous and stinging marine invertebrates.

Corals feed by one of two ways. Some species catch small marine life, like fish and plankton, by using the stinging tentacles on the outer edges of their bodies. Most corals, however, depend on algae called zooxanthellae to provide energy via photosynthesis.

The corals have a symbiotic, or mutually beneficial, relationship with the zooxanthellae, according to the U.S. Environmental Protection Agency (EPA). These algae live inside the coral polyp's body where they photosynthesize to produce energy for themselves and the polyps. The polyps, in turn, provide a home and carbon dioxide for the algae. Additionally, the zooxanthellae provide the coral with their lively colors — most coral polyp bodies are clear and colorless without zooxanthellae.

Some coral species, such as brain coral, are hermaphrodites, which means they produce eggs and sperm at the same time. Sexual reproduction occurs during a mass coral spawning event that, for some species, happens only once a year.

Other species, such as elkhorn coral, are gonochoric, which means they create colonies composed of either all males or all females. Within each coral colony all the polyps will produce only eggs or only sperm. For successful reproduction, the colony must rely on a neighboring colony that produces the other reproductive cell.

The world of coral reefs

Most of the substantial coral reefs found today are between 5,000 and 10,000 years old, according to CORAL. They are most often found in warm, clear, shallow water where there's plenty of sunlight to nurture the algae that the coral rely on for food.

Coral reefs cover less than 1 percent of the ocean floor — all the reefs combined would equal an area of about 110,000 square miles (285,000 square km), only about the size of the state of Nevada. Nonetheless, they are among the most productive and diverse ecosystems on Earth.

About 25 percent of all known marine species rely on coral reefs for food, shelter and breeding. Sometimes referred to as "the rainforests of the sea" for their biodiversity, coral reefs are the primary habitat for more than 4,000 species of fish, 700 species of coral and thousands of other plants and animals, according to CORAL.

Coral reefs are typically divided into four categories, according to CORAL: fringing reefs, barrier reefs, patch reefs and atolls. Fringing reefs are the most commonly seen reef and grow near coastlines. Barrier reefs differ from fringing reefs in that they are separated from the coastlines by deeper, wider lagoons. Patch reefs typically grow between fringing and barrier reefs on the island platform or continental shelf. The rings of coral that make up atolls create protected lagoons in the middle of the oceans, typically around islands that have sunk back down into the ocean.

Coral reefs under siege

Coral reefs are critical marine habitat on which many ocean species depend. Additionally, coral reefs provide an estimated $30 billion annually in direct economic benefit to people worldwide though food, fisheries and tourism, according to the Hopkins Marine Station of Stanford University.

But coral reefs are imperiled by several threats.

The increasing acidification of the ocean — caused when oceans absorb immense amounts of carbon dioxide released into the atmosphere through the burning of fossil fuels — inhibits coral's ability to produce the calcium carbonate exoskeletons they rely on for shelter.

Water pollution, too, is wreaking havoc on coral reefs. Agricultural pesticides and fertilizers, oil and gasoline, sewage discharge and sediment from eroded landscapes make it difficult for coral to thrive, and therefore damage the complex relationships that exist among the plants, coral and other animals that are part of the reef ecosystem.

As the temperatures of the world's oceans increase due to global warming, coral polyps expel the zooxanthellae they depend on for food. Once the zooxanthellae are gone, the coral loses its brilliant color, and all that can be seen is the white exoskeleton; this is referred to as coral bleaching. Coral colonies subject to bleaching usually die off, according to CORAL.

Fishing practices such as cyanide fishing (spraying cyanide in the water stuns the fish to make them easier to catch), "blast fishing" with explosives and overfishing with trawlers can destroy a thousand-year-old coral reef in a matter of minutes.

"Overfishing, ocean acidification and pollution are pushing coral reefs into oblivion," Roger Bradbury, an ecologist at the Australian National University in Canberra, wrote in his New York Times opinion article. "Each of those forces alone is fully capable of causing the global collapse of coral reefs; together, they assure it."

The future of the Great Barrier Reef

The largest coral reef in the world, the Great Barrier Reef, is home to at least 400 individual species of coral and thousands of different species of fish, mollusks, sea snakes, sea turtles, whales, dolphins, birds and more. As with the other coral reefs of the world, this incredible ecological hotspot is under threat.

A heat wave in 2016 caused a large percentage of the corals in the Great Barrier Reef to undergo severe bleaching and death. A 2018 study in the journal Nature Communications found that in just the northern third of the reef, over 60 percent of the shallow-water corals (those below 49 feet, or 15 meters) experienced some degree of bleaching, and 30 percent of the coral died. The study also found that even in the deeper, less-explored areas of the reef (down to about 131 feet or 40 m), nearly 40 percent of the corals had at least partial bleaching.

Healthy reefs lead to healthy oceans, and healthy oceans are vital to all life on Earth. The destruction facing not only the Great Barrier Reef, but also every reef around the world, can lead to the extinction of thousands of species of marine life. In turn, coastlines currently protected by reefs would more readily flood during storms, some islands and low-lying countries would vanish under the water, and the $30 billion industry that coral reefs provide could collapse.

The Australian government has put forth a long-term plan to sustain the Great Barrier Reef. The plan outlines efforts to greatly reduce and eventually eliminate dumping materials and chemicals, reduce fishing and poaching, and monitor the water quality of run-off directed toward reef.

There are also many attempts to rebuild the reef. Scientists are working to breed stronger species of coral that are less susceptible to the warmer waters and grow at an accelerated rate, reported the New York Times. They grow various coral species in the lab and place them in experimental environments designed to reflect the predicted temperature and acidity of the ocean decades from now.

Another group of coral reef ecologists are experimenting with growing corals on steel frames placed over the damaged parts of a reef. Electrical currents sent through the steel frames, accelerates the corals' growth by three to four times, reported New Scientist. It's possible this technique could help rebuild the reef and make the coral more likely to survive bleaching events.

For thousands of years — perhaps hundreds of thousands — a sizable coral reef has stretched across the seafloor in the Atlantic Ocean, near the southeastern part of the U.S. And its existence remained a well-hidden secret until a recent deep-sea expedition brought the thriving ecosystem to light.

Scientists on board the research vessel (RV) Atlantis discovered the reef last week, about 160 miles (257 kilometers) off the coast of Charleston, South Carolina, the HuffPost reported. Cameras on a submersible deployed from Atlanis — the human-operated vehicle (HOV) Alvin — captured the unexpected sight of dense, cold-water coral populations seeding the sea bottom about 0.5 miles (0.8 km) below the ocean surface.

The site was covered with living corals — "just mountains of it" — growing atop the massive, skeletal remains of dead corals that had likely been inhabiting the area for millennia, expedition lead scientist Erik Cordes, an associate professor in the Department of Biology at Temple University in Philadelphia, told the HuffPost. [In Photos: Diving in a Twilight Coral Reef]

Scientists used Alvin to explore the reef and collect coral samples during dives on Aug. 23 and Aug. 24, according to the HuffPost. The researchers discovered copious amounts of Lophelia pertusa, a branching, whitish coral that prefers cold waters and that has previously been found growing at record depths in the Gulf of Mexico.

While tropical corals typically rely on symbiotic algae to survive, L. pertusa does not, and it uses stinging tentacles to stun its prey and guide food into its stomach, according to the National Oceanic and Atmospheric Administration (NOAA).

Corals detected by the Atlantis were found about 16 miles (26 km) to the northwest of corals found earlier this summer by the NOAA RV Okeanos Explorer, which was mapping hundreds of seamounts on the ocean floor, HuffPost reported. Together, the coral-covered area explored by Okeanos and the Atlantis extends for an estimated 85 miles (137 km), layered with enormous, rocky piles of dead coral that likely accumulated over many thousands of years, Cordes told HuffPost.

The RV Atlantis embarked on its 15-day expedition on Aug. 19, part of a 4.5-year collaborative project known as the Deep Sea Exploration and Research of Coral/Canyon/Cold seep Habitats (Deep SEARCH), according to the mission website. 

Until Sept. 2, scientists on the Atlantis will explore deep-sea habitats near the southeastern coastal U.S. They will collect critical data on the distribution of ecosystems and wildlife of the sea bottom in order to more accurately predict how these fragile communities could be disrupted by human activity, NOAA reported on the Deep SEARCH website.

Original article on Live Science.

Watch this coral wave its hands in the air like it just don’t care! But actually, it probably does care, and those aren't really hands — they’re the tentacles of coral polyps.

Although it might look like a sped-up underwater dance party, those tentacles are swinging around looking for food. Coral polyps are the tiny creatures that live in large colonies that make up an entire reef structure. At night, the polyps stretch their long tentacles out of their skeleton to capture the floating plankton they eat, according to the Florida Keys National Marine Sanctuary.

This video is a series of time-lapse clips showing how new polyps feed and develop as the coral structure gets bigger. Peter Kragh, a natural history cameraman, filmed the clips in an aquarium in San Diego over a period of 1 to 3 weeks. [Photos: The Secret Lives of Corals]

"Maybe the most interesting part of the video is seeing how the new polyps seem to appear out of nowhere and start growing," Kragh told Live Science in an email.

The coral in the video is a type of staghorn coral (Acorpora sp.), a hard coral made of calcium carbonate that's deposited by the polyps. Hard corals like this one are responsible for making up the rocky-like structure of a coral reef. The polyps' tentacles are tinted neon green because of tiny algae called zooxanthellae that live inside the polyps and produce bright pigments. Without the zooxanthellae, the polyps would be colorless. [Pretty in Pink: Photos of Bubblegum Coral] 

While ocean acidification and increasing temperatures are threatening many coral reefs in the world, according to the Coral Reef Alliance, coral can be resilient. In the seventh clip of the video, labeled 206-2, you can see where a broken piece of coral (in the middle) heals over and new polyps grow. 

Original article on Live Science.

Hawaii may have started a trend. After the state banned the sale of reef-harming sunscreens earlier this month, the Caribbean island of Bonaire is following suite.

Hawaii's state legislature voted in May to ban the sale of sunscreens containing oxybenzone and octinoxate effective in 2021. These two chemicals have been shown in studies to damage coral by causing them to expel their symbiotic algae — a process called bleaching. The chemicals also impact free-swimming coral larvae, prompting them to prematurely excrete a hard skeleton. In tourist-heavy bays and inlets, sunscreen pollutes the water to a large enough extent to damage reefs, according to 2016 research published in the journal Archives of Environmental Contamination and Toxicology.

Bonaire is a popular tourist site for diving. It's a municipality of the Netherlands located in the Leeward Antilles, not far off the coast of Venezuela.

According to the Bonaire News, the island's council voted unanimously Tuesday (May 15) to follow Hawaii's lead in banning oxybenzone and octinoxate. The precise nature of the ban is yet to be determined, but the council voted to make the ban effective as of Jan. 1, 2021.

In Hawaii, stores will no longer be able to sell sunscreens with the reef-harming ingredients, both of which are chemicals that filter UV light. However, mineral-based sunscreens are still good to go. These sunscreens use materials such as zinc oxide to physically block the sun's rays. They aren't absorbed into the skin, and there is no evidence that they damage coral.

Oxybenzone and octinoxate are also banned or strongly discouraged at a handful of local natural areas around the world. Multiple parks in Mexico's Riviera Maya and surrounding region — including Xel-Ha Park, Cozumel's Marine Park, Chankanaab Beach Adventure Park and Xcaret Park — ban any sunscreen that is not "biodegradable." Approved sunscreens are all mineral-based.

Original article on Live Science.

Hawaii is poised to ban certain sunscreens from sale within its borders in the name of protecting coral reefs. But vacationers will still be able to protect themselves from skin cancer while snorkeling and frolicking in the waves — but might look a little funny.

On Tuesday (May 1), Hawaii's Legislature passed a bill to ban sunscreens containing the common chemicals oxybenzone and octinoxate, effective Jan 1, 2021. The bill is now awaiting a signature from Gov. David Ige.

The ban follows research suggesting that sunscreen drifting off the skin of tourists can damage coral. But only chemical sunscreens are affected — mineral sunscreens that use zinc oxide or titanium dioxide to physically block the sun's rays are still allowed. These sunscreens have fallen out of favor because they often leave a white sheen on the skin, but marine biologists say it's worth looking a little goofy to save reefs. [5 Things You Didn't Know About Sunscreens]

"Any little thing we can do could have a huge impact, because corals are getting it from every side," said Nikki Traylor-Knowles, a biologist who studies stresses on corals at the University of Miami.

What's in a sunscreen?

Coral reefs the world over face a whole load of threats. The most pervasive is climate change, which warms and acidifies ocean waters and causes frequent coral bleaching events. Corals live in symbiosis with algae that conduct photosynthesis from the safety of the coral's bony structure and, in return for that protection, provide the coral food. Bleaching occurs when corals get stressed and expel the algae. Coral can recover from bleaching, but recovery becomes less likely if the ocean conditions remain stressful or if bleaching occurs year after year.

Pollution, including runoff from storm water and untreated sewage, can damage reefs as well, according to the National Ocean Service. But in recent years, scientists have pointed to sunscreen-slathered tourists as a previously unrecognized source of water pollution.

Two sunscreen chemicals, oxybenzone and octinoxate, have been shown to damage corals in a variety of ways. According to 2016 research in the Archives of Environmental Contamination and Toxicology, which John Fauth, a biologist at the University of Central Florida, helped conduct, oxybenzone damages coral DNA, causes coral to bleach, and even prompts free-swimming coral larvae to excrete a hard skeleton prematurely, entombing themselves. The bleaching may be the result of the sunscreen compounds promoting viral infections in the coral, according to a 2008 study. The chemicals are also endocrine disruptors, Fauth said, so they damage corals' ability to reproduce.

Everything counts

It might seem mind-boggling that a few humans slathered in sunscreen could make an impact in the world's biggest ocean, or any ocean for that matter, but these compounds can have effects down to the parts per trillion, Fauth told Live Science.

 In addition, Traylor-Knowles said, sunscreen can quickly become concentrated in the sheltered coves and lagoons where people love to snorkel and swim.

"Other animals, like fish, can swim away from an area that is being impacted by a chemical, right, but corals can't do that," Traylor-Knowles told Live Science. "They just have to sit there and take it."

Hawaii's likely ban of the chemicals is hugely heartening, both Fauth and Traylor-Knowles said. A few tourist areas in Mexico have enacted similar bans, Fauth said, and Hawaii might be the "tip of the spear" for other island nations that depend heavily on tourism.

So, what is a sun-sensitive but coral-loving tourist to do? Cover up and wear mineral sunscreens (though avoid mineral sunscreens that use a nano-form of minerals, which might affect phytoplankton, the base of the ocean food chain).  For their research on sunscreen, Fauth and his colleagues said they were careful to avoid contaminating the water while they took samples: They showered, rinsed all their gear with harsh lab soap and avoided all personal care products, even deodorant, for a week.

"We sort of looked at each other and said, 'This is going to be a smelly mess by the end of the week,'" Fauth said.

But with the help of protective clothing, hats, rash guards and judicious use of shade, the researchers managed to avoid sunburn. Mineral sunscreens make sun protection even easier, and should be seen as a badge of honor, Fauth said.

"You've got on something that's protecting you," he said, "and meanwhile, it's not harming the marine life."

Original article on Live Science. 

Have you ever dug your feet into the warm, soft surface of a white sand beach? Felt the fine, dry grains slide pleasurably between your toes? Thank a parrotfish. Specifically, thank it for its poop. Most of the sand on just about every white beach in the world is the product of generations of the strange family of fish digging their sturdy beaks into ocean-floor coral and chewing chunks of rocky organic matter down to powder. And now, researchers know how the swimming weirdos get through their stony meals without cracking their teeth.

A team of scientists from Lawrence Berkeley National Laboratory, Nanyang Technological University in Singapore and the University of Wisconsin-Madison subjected parrotfish beaks to a Berkeley X-ray machine known as the Advanced Light Source (ALS). The ALS can image organic crystals at a microscopic level. And the analysis revealed a unique woven structure in the crystals in a parrotfish's mouth that could open new frontiers for materials science, the researchers said.

"Parrotfish teeth are the coolest biominerals of all," Pupa Gilbert, a UW-Madison physicist and lead author of the study, said in a statement. "They are the stiffest, among the hardest, and the most resistant to fracture and to abrasion ever measured." [See Photos of the Bizarre Bumphead Parrotfish]

"Stiffness" and "hardness" may sound like synonyms, but they have different meanings in engineering. A stiff object isn't very elastic. Press on it, and it won't bend; pull your finger away, and the material won't bounce back. A hard object resists permanent damage; bash it against a wall, and it won't dent or deform.

The record-stiff, superhard teeth of parrotfish apply enormous force — 530 tons of pressure per square inch — to their coral meals. And those teeth don't break or fall out of the animals' mouths.

And yet, there isn't anything all that chemically interesting about parrotfish teeth, the scientists said. Look at them under a microscope, the researchers explained in their statement, and you'd struggle to differentiate the material from the enamel found in the mouths of all kinds of animals.

Parrotfish have about 1,000 teeth arranged in 15 rows, with new teeth constantly bursting from the soft tissue to replace old ones. That's not all that unusual; many sharks have a similar setup. But parrotfish are unique in the way their legions of teeth fuse together to form their hard beaks.

The real astonishing structure of parrotfish beaks, though, is much smaller, as the researchers said in a paper published online Nov. 15 in the journal ACS Nano.

On the micro scale, the enamel fibers' diameters narrow from an average of 5 microns (5 thousandths of a millimeter) at the bases of the teeth to 2 microns (2 thousandths of a millimeter) near the tips. And the fibers weave together like tight fabric out of a loom, warp and weft aligned at right angles to one another.

That structure, like the one likely holding your shirt together but spun from hard organic crystals, gives parrotfish the superpower of chewing on rock-hard, brittle corals the way you'd bite into a loaf of bread.

Researchers said they might be able to mimic the micro-structure to build synthetic materials for human use. Imagine a set of tools capable of surviving the grinding pressure of 530 tons per square inch against rough, hard coral. It's the biological technology behind every white beach in the world. Who knows where it will go next?

Original article on Live Science.

A hurricane the size of Irma can cause extensive damage on land with massive storm surges, excessive rainfall and raging winds. But what exactly happens below the ocean's surface, in the deep sea, when these storms pass through?

Hurricanes can be death sentences for coral and sea creatures that are territorial, meaning they won't leave their homes to flee to safety, or for creatures that are slow swimmers, such as the seahorse, researchers told Live Science. Other animals, such as sharks and some fish, simply swim out of danger's way.

Man-made objects stationed underwater can be blasted by powerful, hurricane-driven currents, said Curt Storlazzi, a geological oceanographer with the U.S. Geological Survey.Those objects can include long-lost shipwrecks, gas and oil pipelines and fiber-optic cables, he added. [Hurricane Irma Photos: Images of a Monster Storm]

What lies beneath

The chaos starts at the ocean's surface. The hurricane's winds blow against the water, creating waves. As the waves grow taller, they develop more area for the wind to press against, which in turn makes the waves even larger, Storlazzi said.

The water below each wave moves in a circular motion, which sets off another, small circle below it. To visualize it, think of a hula hoop with a somewhat smaller hula hoop below it, continuing until the hoops get very small.

Scientists have learned that these stacked-hoop disturbances — that is, water moving in a circular motion, setting off another circular orbit below it — are only half the distance in length from one wave peak to the next.

"If the distance between subsequent wave crests is 100 meters [328 feet], then below about 50 meters [164 feet] you won't have any of that orbit motion," Storlazzi told Live Science. However, if there is a very long wave length, then this circular moving water can reach all the way down to the continental shelf, which can be hundreds of feet below the water's surface, he said.

"When those orbital motions [get] near the bottom, they can't go through the seabed, so they tend to flatten out," Storlazzi said. "Instead of being circular, they're very horizontal, just back and forth. And those cause a lot of stress, or force imparted on the seabed."

This extremely fast horizontal movement within the ocean can kick up sediment and even move large objects — "you always hear about old sunken ships being unburied in storms because you have very strong horizontal motions," Storlazzi said.

The hurricane's powerful winds can also mix the ocean's cold, deep waters with warmer, shallow waters. "When hurricanes propagate across the ocean, they tend to leave a cooler trail of water in their wake," Storlazzi said. "They're pulling up deep water that's usually colder than the surface water, which is warmed by the sun."

Keep swimming

During a hurricane, fast-swimming fish, such as sharks, usually escape harm, as they can detect small pressure changes in the water, prompting them to swim deeper or farther away, according to a blog written by Brian McNoldy, a senior research associate at the Rosenstiel School of Marine and Atmospheric Science at the University of Miami. [Images: Sharks & Whales from Above]

But slower swimming or territorial fish, as well as crabs, sea turtles and oysters, typically fare poorly during hurricanes. Not only because they get smashed around by the waves but because there's less dissolved oxygen in the water and rapid salinity changes as the ocean's deep and shallow waters mix, McNoldy wrote.

Hurricanes are a mixed bag for coral, which can protect coastlines from waves and storms, according to the National Oceanic and Atmospheric Administration (NOAA).

As the planet, and oceans, warm, more corals are turning white and dying — a process known as bleaching. As mentioned, hurricanes cool the water in their wake, which is welcome news for coral in danger of higher ocean temperatures, said Tyler Smith, an associate research professor of marine science at the University of the Virgin Islands. (Smith managed to evacuate from the Virgin Islands before Hurricane Irma struck this week.)

What's more, some corals depend on high-energy waves to break them up and spread their fragments afar, where they can "take root" in a new area and grow into a new reef, Jennifer Koss, director of NOAA's Coral Reef Conservation Program, told Live Science.

However, hurricanes can also rip apart corals and dump huge amounts of ocean sediment on them, killing the coral, Smith said. In turn, broken corals are more susceptible to disease and death.

Typically, coral reefs ravaged by hurricanes recover in 15 to 20 years, Smith said. But in recent years, these reefs haven't been bouncing back, he said.

"A lot of these corals have lost their resilience because of human factors," Smith said. "Either local factors, like overfishing, which reduces fishes that graze the reef and keep it free of algae and allow for new coral recruits to settle. Or, we're now seeing increasing temperatures, which are increasing both direct death from bleaching and from coral diseases."

Original article on Live Science.

A healthy coral reef is a magical place, teeming with diverse communities of colorful marine life. The enormous, stony structures of well-known reefs such as Australia's Great Barrier Reef can extend for thousands of miles, and appear almost indestructible. But reefs today face a deadly threat from an invisible foe — excess carbon dioxide produced by human activity, which is warming Earth's oceans at an alarming and unprecedented rate, leading to widespread coral bleaching and death.

"Chasing Coral," which premieres today (July 14) on Netflix, offers a window into some of the worst bleaching events that corals have ever faced, all of which have occurred within the last few decades. The documentary features scientists at the forefront of ocean research, and describes the efforts that are already underway to protect vulnerable reefs. The documentary also outlines what still needs to happen to mitigate the effects of climate change and limit global warming, before coral reefs as we know them disappear forever. [Worst Coral Reef Bleaching on Record for the Great Barrier Reef | Aerial Video]

In "Chasing Coral," the filmmakers set out to do something that had never been done before — document the changes in coral reefs over weeks as they bleached and died, to underscore the severity and speed of climate change's impact on reef ecosystems, and to convey the urgency required for individual and collective action to preserve corals in a warming world.    

Scientists first observed large-scale coral reef bleaching — when expanses of multiple reefs turn white across many ocean locations — in the 1980s, the film's chief scientific adviser Mark Eakin, coordinator of the Coral Reef Watch program for the National Oceanographic and Atmospheric Association (NOAA), told Live Science.

A reef's rocky structure is a sprawling skeleton built by a colony of tiny, soft-bodied coral polyps. Corals are extremely sensitive to changes in water temperature, and when conditions are stressful — if waters become too warm for too long — they expel the microscopic algae that lend them their color and make their food. Bereft of algae, corals' transparent flesh reveals the white skeleton underneath, making the reef appear "bleached." If these conditions persist, the corals will eventually die.

Researchers identified the first global bleaching event in 1998, which was followed by another in 2010, Eakin said. A third mass bleaching episode that began in 2014 was still underway in 2015, when the "Chasing Coral" filmmakers installed stationary time-lapse cameras at reefs in Hawaii and in the Bahamas. And the bleaching continued into 2016, as the team shot manual time-lapse footage at locations at the Great Barrier Reef.

This large-scale coral bleaching was the first global event to last for more than a year, and its effects were so devastating that even the filmmakers were stunned by what they saw. One especially sobering scene shows Zackery Rago, a camera technician for the film and a self-described "coral nerd," at a site on the Great Barrier Reef, holding a piece of dying coral as its transparent flesh disintegrates in his hands.

"It was far worse than we ever thought it would be," Jeff Orlowski, the film's director, told Live Science. But that made them only more determined to share what they found, he said.

"We knew we need to get this story out to the world," Orlowski said. "This was too important to let go, we needed to get imagery that was as powerful as possible." [Gallery: Peek Inside a Coral Nursery]

Not all corals die after bleaching, and some species are proving to be more resilient than others, Ruth Gates, "Chasing Coral" science adviser and director of the Hawaii Institute of Marine Biology at the University of Hawaii, told Live Science.

Scientists are studying the factors that help corals recover from bleaching, ranging from genetics to alliances with microorganisms to partnerships with more resistant corals. But seas are heating up so quickly and bleaching events are occurring so frequently that even hardier corals may ultimately not survive, Gates said.

"The intensities of temperatures are overwhelming everybody's capacities," she said. "Temperatures have been so high for so long that even the most resistant corals, in some cases, are not looking good."

And no mitigation strategy will be enough to save coral reefs if fossil fuel use continues unchecked and Earth continues to warm, Gates told Live Science.

"If we don’t intervene in the next 10 years, we'll be discussing the demise of reefs in our lifetime," Gates said.

While "Chasing Coral" doesn't pull any punches about the precarious future of reefs, it also highlights the fascinating biology of corals and the beauty of reef ecosystems. They are home to diverse populations of fish and invertebrates, many of which sustain human populations as well, Orlowski said.

And perhaps the film will help audiences to recognize the urgency of preserving these threatened environments, particularly when climate change's devastating impact is already underway, according to Eakin.

"A lot of people feel that climate change is something that's going to happen in the distant future, or in some faraway place," Eakin told Live Science. "This shows that there are very important ecosystems that people depend on that are already affected by climate change — and it's getting worse. So hopefully that'll help bring people together on the fact that we need to do what we can to save these reefs," he said.

Original article on Live Science.

Its biodiversity may be priceless, but the Great Barrier Reef has a real economic value — 56 billion Australian dollars ($42.5 billion) of real economic value, to be precise, a new report finds.

The report, published by the financial consultancy Deloitte Access Economics, also found that the enormous coral reef off of Queensland, Australia, supports 64,000 jobs in that country and contributed AU$6.4 billion ($4.9 billion) to Australia's economy in the 2015 to 2016 fiscal year. But the reef is under threat from climate change, with back-to-back bleaching episodes threatening the survival of vast swaths of coral.

"This report sends a clear message that the Great Barrier Reef — as an ecosystem, as an economic driver, as a global treasure — is too big to fail," Steve Sargent, the director of the Great Barrier Reef Foundation, said in a statement. [Image Gallery: Great Barrier Reef Through Time]

Economic boon

The Great Barrier Reef Foundation commissioned the report, which drew from publicly available economic data as well as surveys of Australian residents. The analysis counted direct economic benefits, such as income made by tour-dive companies or commercial fishing supported by the reef. If also included indirect economic benefits, like the boon to restaurants and hotels near the Queensland coast and the economic value of the research being done on the Great Barrier Reef.

Ninety percent of the AU$6.4 billion the reef brought into Australia between 2015 and 2016 came from direct tourism activities. [Images: Colorful Corals of the Deep Barrier Reef]

Iconic value

Beyond the direct and indirect benefits to Australia's economy, the reef also provides what Deloitte Access economists called "indirect" or "non-use" value. This is the value the Great Barrier Reef has by simply existing: its social value, its importance for biodiversity and its importance as a point of Australian identity and pride.

Researchers used a survey of 1,000 Australians and 500 non-nationals to try to estimate this indirect value. They found that 54 percent of Australians and 63 percent of international respondents said they'd be willing to pay to protect the Great Barrier Reef. Of those people, most said they were motivated by protecting the reef for future generations (70 percent of Australians) or because the reef is "important to the planet" (62 percent of international respondents). Of those who said they wouldn't be willing to be levied to protect the Great Barrier Reef, most said they couldn't afford such a tax, and others said the funding should come from another source. Only 2 to 3 percent said they did not think the Great Barrier Reef was important or under threat.

The AU$56 billion ($42.5 billion) valuation comes from extrapolating the direct and indirect economic benefits of the reef over the next 33 years, until 2050. Over that time period, the direct-use benefit from tourism is AU$29 billion ($22 billion). Other contributors to that number include ecosystem services, like the ecological functions the reef conducts to cycle nutrients and protect the coastline, and the "brand value" of the reef in raising Australia's reputation as an international destination.

The reef also has value that can't be estimated in dollars, the economists concluded. It's an important place for indigenous Australian cultural and religious heritage, and archaeological sites along the reef have revealed artifacts, such as stone tools and rock art, that hint at the earliest occupants of Australia.

Original article on Live Science.  

Specialized, self-lubricating smackers are the key to the fish's slobbery success, scientists discovered. The wrasses' mouths are unusual, to say the least — their fleshy pucker is dramatically different from the lips of their cousins that don't dine on stinging corals.

Wrasses that don't eat corals have smooth, thin lips that don't quite cover their teeth. But L. australis' full and fleshy lips resemble a mushroom's gills: They're packed with thin, vertical, slime-slick membranes. Their lip surface is similarly covered in folds of tissue that secrete generous amounts of mucus, coating the lips like the world's gloppiest lip gloss, and protecting the fish from the corals' venom, according to a new study. [Photos: The Freakiest-Looking Fish]

If you've ever suffered from the dripping nose that accompanies a cold, just imagine that same sensation in your lips, and you'll have a pretty good idea of the tubelip wrasse's slimy adaptation, study co-author David Bellwood, a reef fish researcher and professor at the College of Science and Engineering at James Cook University in Australia, said in a statement.  

The researchers captured high-resolution images of the fishes' lips using a scanning electron microscope, revealing the unusual mushroom-like folds that produced copious amounts of mucus.

This peculiar modification enables the wrasses to accomplish what only 128 species of reef fish (out of 3,000 species) can do: dine on coral flesh that's packed with stinging, needle-like structures and wrapped around a sharp skeleton.

To feed on these potentially mouth-slicing corals, the wrasses literally suck it up, the study authors wrote. High-speed video revealed that the fish position their mouths around their coral target, creating a seal with their mucus-coated lips to increase suction power, and then slurp up the outer layer of coral mucus and bits of its flesh.  

Little is known about how fish use their lips, and the diversity of lip shapes among reef fishes raises intriguing questions about the variety of roles that lips might play in how fish eat, the authors wrote in the study.

"One always assumes that fishes feed using their teeth," Bellwood said in the statement. But just as lips play a role in humans' eating, "the lips can be an essential tool" for fish as well, he added.

And lip service isn't the only ingenious use for mucus employed by this fish group.

Wrasses are also known to produce slimy mucous cocoons that act as a type of protective sleeping bag — a behavior that was long thought to protect the fish from predators, researchers reported in a study published online in the November 2010 issue of the journal Biology Letters. However, the scientists found that the fishes' slime "sleeping bags" act as a defense against bloodsucking parasites, much as mosquito nets protect humans against biting insects, the study authors wrote.

But not all mucus is created equal, and the chemical recipe for the tubelip wrasses' special mouth mucus is yet to be discovered. Deciphering the so-called "magic of the mucus," as the study authors called it, is the next slippery question that the researchers plan to address, they wrote in the study.

The findings were published online June 5 in the journal Current Biology.

Original article on Live Science.

Two-thirds of the length of the Great Barrier Reef is suffering from bleaching, a condition likely to cause mass coral die-offs.

The Australian Research Council (ARC) announced yesterday (April 10) that 900 miles (1,500 kilometers) of reef have bleached in 2017, meaning the symbiotic (and often colorful) algae within the coral's tissues are expelled. The most severe impacts were seen on the middle third of the reef's length; the entire reef stretches for 1,430 miles (2,300 km) off northeastern Australia.

Bleaching doesn't necessarily kill corals outright, but leaves them crippled in their ability to get enough nutrients to survive. The algae within the corals, called zooxanthellae, provide the corals with crucial nutrients and help the corals remove waste. Without them, the corals are more vulnerable to disease. If the algae are unable to recolonize the corals, the corals are also vulnerable to starvation. [See Images of the Great Barrier Reef Through Time]

"This is the fourth time the Great Barrier Reef has bleached severely — in 1998, 2002, 2016 and now in 2017," James Kerry, a marine biologist with the ARC Center of Excellence for Coral Reef Studies, said in a statement. "Bleached corals are not necessarily dead corals, but in the severe central region we anticipate high levels of coral loss."

Lost hope

In 2016, aerial surveys conducted by the ARC Center of Excellence revealed the most severe bleaching on record at the time. That bleaching event was partially spurred by El Niño, which brings warm water to reefs. High temperatures are a major source of stress for corals, which respond by expelling their algae, according to the National Oceanic and Atmospheric Administration (NOAA). During last year's bleaching event, scientists found some hope in that the lower two-thirds of the Great Barrier Reef had not been badly affected, and said that the bleached areas might bounce back.

"It's really just a matter of whether or not we get another bleaching event in the next 10 years that would impede recovery," Rebecca Albright, a marine biologist with the Carnegie Institution for Science in Washington, D.C., told Live Science at the time.

That second bleaching event has already arrived, and in a non-El Niño year, to boot.

"Mass bleaching events 12 months apart offer zero prospects of recovery for reefs that were damaged in 2016," Kerry said.

New damage

Whereas, the new damage to the reef is most severe in the middle third, in 2016, the northern end of the reef took the most damage, the ARC reported. Tropical Cyclone Debbie, which made landfall in Australia last month, worsened the situation by  damaging a swath of reef 62 miles (100 km) wide.

But scientists are most concerned about the main culprit in reef bleaching events: global warming. Climate change not only heats up the oceans, it increases ocean acidification, another stressor for coral. Changes in ocean currents might affect reefs, as well, while altered precipitation patterns can influence runoff into vulnerable areas, according to NOAA.

Already, 80 percent of hard coral cover in the Caribbean is gone, a 2003 study in the journal Science reported. The Indo-Pacific, home to 75 percent of the world's reefs, lost approximately 1 percent of its coral each year over the past 20 years, according to a study published in the journal PLOS ONE. In the 1980s, the PLOS ONE study authors reported, coral cover in the Indo-Pacific averaged 42.5 percent, an average that dropped to 22.1 percent by 2003. Before-and-after pictures show the rapid pace of change globally.

Original article on Live Science. 

A newfound species of colorful marine snail slings nets of mucus like superhero web slinger Spider-Man and is "kind of cute," according to the scientist who found and described it.

The tiny sea creature belongs to a group known as worm snails — soft-bodied mollusks encased in tubular shells with an opening at one end. Their hatchlings crawl freely, but they soon attach their shells permanently to hard substrates — like corals or rocks — and are entirely stationary as adults.

Researchers found the new species attached to a shipwreck that had been designated as an artificial coral reef in the Florida Keys. Though the worm snails were fixed firmly in place, they likely originated far away and are not native to that part of the Atlantic Ocean, scientists wrote in a new study. [Alien Invaders: Destructive Invasive Species]

The newly described snail, Thylacodes vandyensis (thy-la-KOH'-dees van-dee-EN'-sis), was named after the ship where it was found: the USNS General Hoyt S. Vandenberg, aka "Vandy." A former World War II naval transport vessel, "Vandy" rests on the sea bottom of the Florida Keys National Marine Sanctuary. The ship, which measures 522 feet (159 meters) long, was deliberately scuttled on May 27, 2009, to become the world's second-biggest artificial coral reef, CNN reported that day.

Slime nets: useful and delicious

T. vandyensis snails vary in size, but on average, they are "about the length of a finger," according to study lead author Rüdiger Bieler, a curator of zoology at The Field Museum in Chicago. Their shells measure up to 1 inch (25 millimeters) long and are tipped at one end by a narrow opening of about 0.2 inches (5.5 mm) in diameter, Bieler and his colleagues wrote in the study.

The snails are colorful creatures, with bright-orange faces that are visible through the openings in their shells, Bieler said. And they sport four appendages on their worm-like bodies, two of which are connected to slime glands similar to those used by garden snails to produce sticky trails.

But T. vandyensis uses its slime in a different way: It casts mucous strands in Spidey-style nets to trap plankton and other organic material. Afterward, it hauls in its prizes, eats the gooey net along with whatever food it was able to catch, and recycles the slime to produce a new snare, Bieler told Live Science.

There may even be chemical agents in the nets that protect the snails from predators. Another group of scientists working with worm snails in the Red Sea found evidence of bioactive metabolites — compounds affecting living tissues — in their slime nets, which could explain why predatory fish keep their distance from the worm snails in Florida, Bieler said.

"If one of the snails' tubes is damaged, the fish will eat them," he said. "But as long as there's a mucous net, they stay away — apparently, the mucous net also seems to be a means to deter the fish."

Opportunistic invaders

Scientists first spotted three of the snails on the shipwreck in 2012. Though Bieler had worked with this family of snails since the 1990s, he had never seen it in the western Atlantic before, and the research team suspected that it might be a new species, Bieler said.

When the researchers returned to the wreck less than two years later, the snails numbered in the tens of thousands, Bieler said. Based on their knowledge of worm snails, specimens from museum collections documenting local species, and DNA analysis, the researchers determined that the worm snails belonged to an undescribed species. Genetic evidence confirmed that the species' closest relatives were all from the Pacific Ocean, hinting that the animal was not native to the region, the study authors wrote.

In fact, invaders from the Pacific, including a large oyster species, had already been identified on the shipwreck, Bieler noted.

"Other species have taken the same pathway," he said. "That made it even more likely that this new one may have come from the Pacific."

The new snail is not likely to be the last invader to settle on this artificial reef, Bieler said. Any recently sunken vessel in which a reef ecosystem is still forming and where predators have yet to claim their territory offers the perfect opportunity for a wandering species to settle in — "even a fairly wimpy one," he told Live Science.

"I would like to do a monitoring program along the coastline to involve divers and dive programs," Bieler said. "There are so many people out there taking photographs — we can alert each other about new arrivals and unusual things that are popping up."

The findings were published today (April 5) in the journal PeerJ.

Original article on Live Science.

Large sections of the Great Barrier Reef are already dead, and scientists warn that the rest of the coral organisms that make up the sprawling reef ecosystem will die if global warming continues unabated.

After a yearof record-high-breaking temperatures in 2016, the Great Barrier Reef experienced its worst coral bleaching event on record, as the tiny coral animals evict their color-giving partners — algae that photosynthesize and are the reason for vibrantly hued reefs. Now, scientists have returned to the reef to measure the coral bleaching that has occurred this summer (which begins in December in the Southern Hemisphere) compared to last summer.

Scientists from 10 research institutions across Australia, representing the National Coral Bleaching Taskforce, will spend the next few weeks conducting air and underwater surveys of the Great Barrier Reef. [Image Gallery: Great Barrier Reef Through Time]

"We're hoping that the next 2-3 weeks will cool off quickly, and this year's bleaching won't be anything like last year," Terry Hughes, lead author of a study describing the team's findings and the convener of the task force, said in a statement. "The severity of the 2016 bleaching was off the chart."

Hughes, who is also a marine ecologist and director of the Australian Research Council Centre of Excellence for Coral Reef Studies, noted that 2016 was the third major bleaching event, and most devastating, to affect the Great Barrier Reef. The catastrophic bleaching last year impacted a region of the reef approximately 500 miles (800 km) in length. (The entire reef is about 133,000 square miles, or 344,400 square kilometers.) Heat waves in 1998 and 2002 also caused massive bleaching of the reef.

Past exposure to bleaching does not make coral reefs any more tolerant to new bleaching events, Hughes said. Once measurements of the bleaching extent this year are completed, they may reveal that 2017 was the fourth major event, Hughes added.

"It broke my heart to see so many corals dying on northern reefs on the Great Barrier Reef in 2016," Hughes said. "With rising temperatures due to global warming, it's only a matter of time before we see more of these events. A fourth event after only one year is a major blow to the reef."

Bleaching occurs when corals are stressed from phenomena such as warmer-than-average waters for an extended period of time. In response, corals, which are actually little organisms called coral polyps, expel the algae that lend them their color and provide them with food. This gives the coral a bleached appearance, and if bleaching continues for too long, the algae may not be able to recolonize the coral.

Though overfishing and poor water quality can also stress coral reefs, climate change — and the resulting warmer oceans — is the leading cause of bleaching, said study co-author David Wachenfeld, director of reef recovery at the Great Barrier Reef Marine Park Authority.

"Global warming is the No. 1 threat to the reef," Wachenfeld said. "The bleaching in 2016 strongly reinforces the urgent need to limit climate change as agreed by world leaders in the Paris Agreement, and fully implement the Reef 2050 Plan to boost the reef's resilience." (The Reef 2050 Plan aims to sustain and conserve the Great Barrier Reef, including annual reef health reports and denying development projects that might harm the reef.)

Details of their research on the Great Barrier Reef bleaching events were published online yesterday (March 16) in the journal Nature.

Original article on Live Science.

MARINE CORPS BASE HAWAII — Whether it's the noxious gases rising from the Kilauea volcano, or the lively coral reefs that sprawl across the seafloor around the island chain, Hawaii's ecosystems are under some serious scientific scrutiny this month.

Researchers are here gathering data using NASA's high-altitude airplanes, outfitted with cameras that capture visible light as well as infrared radiation. One airplane, the ER-2, can soar to 67,000 feet, or "the edge of space," as NASA systems engineer Michael Mercury put it. From that height, on daily flights over the islands, the cameras snap images that the scientists then stitch together and analyze, Mercury said, explaining the project at a media briefing that the space agency held here on Wednesday (Feb. 8). [Earth Pictures: Iconic Images of Earth from Space]

The goal of this current work in Hawaii is to find the best ways to use these measurements to gain new insights into volcanic activity and coral reef health. For example, scientists studying Hawaii's active volcano are trying to refine their models that predict exactly how and when the "vog," or volcanic smog that forms from Kilauea's gases, will blanket Hawaiian cities instead of blowing out over the Pacific. Other researchers, who study coral reef ecosystems, are using the images from the high-altitude flights to better understand what aspects of water quality make the difference between a thriving reef and one that is overgrown with algae.

But there is a larger goal, too. NASA has plans to launch an Earth-observing satellite into low-Earth orbit in 2022. That project, called the HyspIRI mission (or Hyperspectral Infrared Imager), will provide researchers with images of Earth's surface that are similar to those being gathered now in Hawaii, and from ecosystems all over the world.

The current project in Hawaii will help the researchers to figure out exactly which instruments and equipment are most useful for their work, and should be the ones that are loaded up onto that satellite.

Eventually, the satellite could be used to gather data not only on volcanoes and corals, but also on many other features that change the Earth's surface over time, such as wildfires that destroy vegetation, thinning glacial ice or changes in the health of croplands.

Once the HyspIRI satellite is in place, researchers plan to use it in conjunction with aircraft- or ground-based instruments. "The satellite might see something new, [and] point us to new places to go with the airplane," Randy Albertson, deputy director of the NASA Airborne Science Program, told Live Science. [Colorful Creations: Incredible Coral Photos]

In the meantime, the Hawaii projects are in full swing. In the coral project, the images taken by the instruments aboard the aircraft can help the researchers spot changes in the color of a reef, said Steven Ackleson, an oceanographer with the Naval Research Laboratory in Washington, D.C., who is in Hawaii to work on the project. 

"Reef pigments come from both the zooxanthellae and from the corals themselves," Ackleson told Live Science, using the scientific term for the algae-like organisms that live in symbiosis with the coral polyps. "Colors indicate health," he said.

The researchers want to figure out the best ways to draw information from the images to determine coral health, he said. For example, the scientists are hoping to learn more about why some types of zooxanthellae tolerate warming waters better than others. The answer may involve differences in the chloroplasts between the different types of zooxanthellae, he said.

The researchers who are working on the volcano project are using the images to better study the composition of the gas plume that arises from Kilauea, and how it changes as the plume spreads out, said Vincent Realmuto, a geoscience researcher at NASA's Jet Propulsion Laboratory.

A key part of the project is looking at how the plumes affect Hawaii's air quality, Realmuto said.

For example, one question the volcano researchers are trying to answer with the new data is exactly how quickly the sulfur dioxide gas that the volcano emits becomes aerosolized, meaning it combines with other compounds to form particulate matter, which can be harmful to human health.

The current estimate is that process takes 10 hours, Realmuto said. But that estimate is very rough. "The local temperature, the humidity, the topography – all of these impact the conversion rate," he said. The new data will help the scientists to create better models to predict the formation and movements of the particulate matter, which could lead to better forecasts of the vog. [The 10 Biggest Volcanic Eruptions in History]

Albertson noted that even when it launches, the new satellite won't eliminate the need for gathering data from instruments aboard aircraft and on the ground. Ground-based instruments can gather measurements on a much finer scale than the satellite will. But the satellite's capacity to get images from the entire Earth in a short amount of time will be a huge advantage for researchers.

To put this in perspective, Mercury said, the current six-week effort will capture images, using the visible-light camera, for most of Hawaii. If that camera were on a satellite, for the same amount of time, the researchers would be able to capture the same level of imaging for the entire Earth's surface, four times over, he said.

Originally published on Live Science.

Sloping toward twilight

Most research on coral reefs has been done in shallow waters, where it's relatively easy to scuba dive. But there's a whole new world in the ocean's mesophotic zone, where only a small percentage of sunlight penetrates. Mesophotic reefs, also known as twilight reefs, exist in a perpetual state of dim blueness. Here, a reef in the northern Red sea slopes toward the mesophotic zone.

[Read the full story on the twilight coral reef]

Bioflourescent coral

The corals in mesophotic reefs have evolved to thrive on photosynthesis, despite limited light. Here, a specimen of Stylophora coral fluoresces under ultraviolet light. New research published in the journal Frontiers in Marine Science finds that the symbiotic algae inside these corals, whose photosynthesis powers the coral, have adapted the molecular machinery that turns sunlight into energy in order to make the process more efficient. These corals live in the northern Red Sea, off the coast of the city of Eilat, Israel.

Specialty diving

To dive to 213 feet (65 m), researchers must use specialty equipment. Commercial scuba divers don't usually dive below about 130 feet (40 meters). Here, marine scientists David Gruber and Oded Ben-Shaprut use rebreather systems with a mixture of three gases in order to decrease the risk of nitrogen narcosis, a dangerous drunken state caused by breathing nitrogen at high pressure. Divers can stay at mesophotic depth using these systems for up to an hour, Gruber told Live Science, but they usually spend less time than that. The longer they dive, the slower they must ascend to avoid decompression sickness, or "the bends."

Ready to dive

Marine biologist David Gruber of The City University of New York prepares for a dive to the mesophotic zone off of Eliat, Israel. Researchers conducted dives over the course of four years to study the corals in dim reefs. They gradually transferred deep corals shallow and shallow corals deep, moving the specimens a mere 16 feet (5 meters) every two weeks.

[Read the full story on the twilight coral reef]

A blue world

Only blue light can penetrate into the ocean's mesophotic zone. Here, divers explore a coral wall in this dim, blue world. Researchers found that shallow corals from about 10 feet (3 meters) depth could barely survive when brought down to 213 feet (65 meters). Deep corals brought to shallow waters died rapidly, though: They simply couldn’t take the intensity of the sun higher in the water column.

Deep dive

Marine scientist Shai Einbinder dives deep in the northern Red Sea to explore the physiology of corals adapted to dim light. Deep mesophotic reefs are little-explored compared to shallower, easier to reach reefs. They're too shallow for most remotely operated vehicles (which are expensive to use), and too deep for most scuba divers.

Bring your own light

Diver and marine biologist Shai Einbinder digs in his dive bag in the dim mesophotic zone of the northern Red Sea. Einbinder and other divers to this depth bring their own light, as only a very small amount of sunlight can penetrate down to 213 feet (65 meters), where much of this study was conducted.

[Read the full story on the twilight coral reef]

An unknown world

Marine biologist Shai Einbinder during a dive to the twilight reefs off the coast of Eilat, Isreal. Mesophotic reefs are found the world over. A recent study of reefs 300 feet (90 meters) down near Hawaii revealed colorful fish and meadows of gently waving algae. In the Red Sea, researchers discovered adaptations in the symbiotic algae in corals that have never been seen before in any photosynthetic organism.

More than 200 feet (60 meters) below the ocean's surface, where the water is cold and only about 1 percent of the daylight above penetrates, is a dim, blue world filled with little-understood creatures. Now, researchers have discovered that the corals that inhabit this "twilight zone" have a never-before-seen adaptation that enables them to eke out enough light energy to survive.

The photosynthetic algae that live on and power these corals have unusual cellular "machinery" that enables them to conduct photosynthesis more efficiently than species that live at shallower depths, the researchers reported Oct. 17 in the journal Frontiers in Marine Science.

"It's unlike anything we've seen on land, or anything we've even seen in the shallow reefs," said David Gruber, a marine biologist at the City University of New York and one of the researchers on the study. [See Photos of the Deep 'Twilight' Coral Reefs]

Capturing a limited resource

On land and in the water, plants use cellular structures called light-harvesting complexes, or photosynthetic antennas, to capture photons (particles of light) and transfer them to the photosynthetic complexes that convert light into usable energy. The photosynthetic antennas are made of various proteins and chlorophyll pigments. In dim forests on land, plants in the underbrush often evolve very large antenna complexes to wring every drop of light out of the sky, Gruber said.

But that's not what the researchers found 213 feet (65 m) down in the northern Red Sea when they collected coral called Stylophora pistillata from reefs there. Inside the coral is symbiotic algae called Symbiodinium, which provide the coral oxygen and energy from photosynthesis in exchange for nutrients and protection. This makes for relatively easy living in shallow reefs, where sunlight is abundant. But below about 130 feet (40 m), the ocean gets dim. This is the "mesophotic" zone, where it's always twilight. At about 330 feet (100 m), only 1 percent of the sunlight above can reach down below. And only blue wavelengths of light can penetrate.

It might make sense for algae living in the mesophotic zone to build huge photosynthetic antennas. But that's not what Symbiodinium does. In fact, when Gruber and colleagues from the Hebrew University of Jerusalem and the University of Haifa, both in Israel, analyzed the deep-living algae, they found that the algae antenna structures were actually smaller than that of shallower Symbiodinium algae.

Extreme environment

Instead of building bigger antennas, the algae modified its light-gathering system. Plants like algae have two types of cellular machines for converting light into sugars: photosystem I and photosystem II. Symbiodinium relies more heavily on photosystem II but positions the cellular machinery close to the machinery of photosystem I. This makes it easier for the two systems to share energy. They also adjust the types of light-snatching proteins in their cellular membranes, the researchers said. [Images: Colorful Corals of the Deep Barrier Reef]

Diving to these coral habitats is hard for humans; commercial scuba divers don't usually go below about 130 feet. To get to the twilight zone of the Red Sea, the researchers, led by lead diver Shai Einbinder, donned tri-gas rebreather systems, which enable divers to go lower while facing a smaller risk of serious problems such as nitrogen narcosis (an altered state of consciousness that occurs when nitrogen enters the bloodstream at the increased pressures seen at extreme water depths). Still, divers stay down only a few minutes because they must ascend very slowly to equilibrate to the lower pressures at the surface and thus avoid decompression sickness, also known as "the bends", Gruber said.

Over the course of four years of diving, the scientists took some samples of deep-reef coral and transferred them to shallow environments, and took shallow corals and transferred them to deeper areas. They did this slowly, moving the corals only 16 feet (5 m) every two weeks. They found that the corals collected in water depths of about 10 feet could hang on to life at 213 feet. Corals from the deep, however, couldn't survive at shallow depths. They lacked the natural compounds that protect corals from the sun's damaging ultraviolet light.

"They didn't have the 'sunscreen,'" Gruber said. "The light was just burning them out."

The researchers studied only one species of algae, and there are probably many more adaptations among the photosynthesizers of mesophilic reefs, Gruber said.

"I'm never unimpressed by the way nature evolved unique traits to allow life in some of the most seemingly unhospitable places," he said.

Original article on Live Science.

Behind Australia's iconic Great Barrier Reef hides another large, doughnut-shaped reef, according to a recent study.

Using laser data from the Royal Australian Navy, scientists found a large field of unusual circular mounds behind the familiar Great Barrier Reef. Upon further research, they discovered that the structures are Halimeda bioherms — geological formations created by green algae. [Images: Colorful Corals of the Deep Barrier Reef]

"We've known about these geological structures in the northern Great Barrier Reef since the 1970s and '80s, but never before has the true nature of their shape, size and vast scale been revealed," Robin Beaman, a research fellow at James Cook University in Australia and part of the team that discovered the reef, said in a statement.

The scientists called the discovery "vast," as they've mapped about 2,300 square miles (6,000 square kilometers) of the reef. Each doughnut-shaped mound measures 650 to 980 feet (200 to 300 meters) across and up to 33 feet (10 m) deep at the center.

The structures form "a significant inter-reef habitat" covering a greater area than nearby coral reefs, said Mardi McNeil, lead author of the new study and a marine geoscience research student at the Queensland University of Technology.

This bioherm field raises questions about the effects of climate change and the reef's vulnerability, because Halimeda may be susceptible to ocean acidification and warming, the scientists said. Warmer ocean temperatures cause coral bleaching — a phenomenon that occurs when coral are stressed by the warmer-than-average waters,. This causes the coral to expel the algae that live in them, which can be fatal to the reef if bleaching continues for too long and algae are unable to recolonize. Earlier this year, Australia's National Coral Bleaching Taskforce (NCBT)announced that more than 90 percent of the Great Barrier Reef shows signs of bleaching, which has been accelerated by record heat this year.

Further study of the new reef could offer new avenues of research into the impact of climate change and coral bleaching, Beaman said.

"For instance, what do the 10- to 20-meter-thick [33 to 66 feet] sediments of the bioherms tell us about past climate and environmental change on the Great Barrier Reef over this 10,000-year timescale?" he said. "And what is the finer-scale pattern of modern marine life found within and around the bioherms now that we understand their true shape?"

Similar to the rings of a tree, coral rings can offer scientists information about the age of the coral and the environment in which it formed. Beaman added that further research of the site would include taking sediment samples and continuing more detailed surveys of the area. The research team will also use autonomous underwater vehicles to investigate the physical, chemical and biological processes of the structures.

The study was published online Aug. 24 in the journal Coral Reefs.

Original article on Live Science.

A blob of a coral has been caught violently pulsating, with tentacles wriggling every which way, as it ejects its algal residents in a time-lapse video of the phenomenon called bleaching.

The video revealed for the first time how the mushroom coral Heliofungia actiniformis, which is a single polyp, physically reacts to heat stress. The results gave scientists more information about how corals will respond to warming seas that are associated with climate change, the researchers said.

"Mass coral bleaching events are a concern for scientists globally with recent events on the Great Barrier Reef highlighting the threat of elevated water temperatures to the heath of reef ecosystems," Luke Nothdurft, of Queensland University of Technology (QUT) in Brisbane, Australia, said in a statement. [Video: Watch the Blob-Like Coral Pulsating to Evict Its Algal Residents]

Like other corals, H. actiniformis provides a cozy home for colorful algae called zooxanthellae. In return for the aquatic abode, the zooxanthellae — in this case a species of Symbiodinium — photosynthesize and provide the coral polyp with food. But when the going gets tough, such as warming waters, the coral can no longer afford to host the tiny tenants. The process of ditching the algae is called bleaching because the coral loses its colorful veil.

Though scientists knew coral bleaching occurred, they didn't know all the details of how the polyps evicted their residents.

To find out, Nothdurft and study lead author Brett Lewis, also of QUT, kept H. actiniformis in aquariums; over a period of 12 hours, the scientists increased the temperature of the aquarium water from 26 degrees Celsius to 32 degrees Celsius (79 to 90 degrees Fahrenheit). The temperature was kept at the highest level for up to eight days, according to a paper on the study published online Aug. 5 in the journal Coral Reefs.

Within hours of the temperature rising, the mushroom corals began to inflate their bodies and then "suddenly and violently contracting and ejecting Symbiodinium through their oral openings over the four- to eight-day duration of the experiments," Nothdurft said in the statement.

In the video, a green plume of the algal cells can be seen coming out of the coral's mouth. During the pulsing, the coral ballooned to 340 percent of its normal body size of about 3 inches (7 centimeters) high and about 6 inches (15 cm) across, as seen in images in the journal article, the researchers found.

"Seeing how pulsed inflation was critical to the bleaching process was amazing," Lewis told Live Science. "This type of pulsing is documented in other species of coral as a way to mitigate other stressors, but this was the first time observing its role in coral bleaching."

If the heat stress goes away, the algae may return to the coral, the researchers said. "If the Symbiodinium is removed from the host and does not recolonize quickly, the corals can die," Nothdurft said.

Original article on Live Science.

Getting peed on is a good thing, at least for coral reefs, scientists have found.

When fish let loose, they release phosphorus into the water. This, combined with nitrogen excreted from their gills, is crucial for coral reef survival and growth, according to recent studies.

Now, new research shows just how much this "fishy waste" matters. When scientists studied areas with heavy fishing, they found that almost half of the key nutrients needed to maintain a healthy reef ecosystem were missing. [How Much of the Ocean Is Whale Pee (and Worse)?]

That's right — large, predator fish are needed to mist the reefs with their pee, study lead author Jacob Allgeier, a postdoctoral researcher at the University of Washington's School of Aquatic and Fishery Sciences, said in a statement.

"Fish hold a large proportion, if not most, of the nutrients in a coral reef in their tissue, and they're also in charge of recycling them," Allgeier said. "If you take the big fish out, you're removing all of those nutrients from the ecosystem."

To study the impact of these nutrients, researchers surveyed 143 fish species at 110 sites across 43 Caribbean coral reefs. Some reefs had few fish because of commercial fishing, whereas others were marine preserves with fishing bans.

Reefs with many large, predator fish had the healthiest levels of nutrients, the researchers found. Meanwhile, reefs with few large fish had about 50 percent fewer nutrients, including phosphorous and nitrogen, which are essential to their survival, the researchers said.

"This study is useful to understand alternative ways fishing is affecting coral reef ecosystems," Allgeier said.

Big fish

When fishers target big fish — such as grouper, snapper and barracuda — the fish, and their pee, disappear, the researchers said.

Normally, fish take shelter in coral reefs during the day, whiling away the time as they relieve themselves. At night, they typically forage for food within the reef communities.

Researchers have known about this behavior for decades. A 1983 study published in the journal Science found that schools of fish did this peeing-during-the-day routine within coral communities, and that corals with these schools grew more than twice as fast as reefs without schools.

Allgeier said the results of the 1983 study inspired him to conduct his new research. He knew that coral reefs operate on a "tight" nutrient cycle, meaning they need an efficient transfer of nutrients in order to grow. Fish help regulate this cycle with their pee and gill excretions, he said.

So Allgeier spent four years measuring how many nutrients fish released, which allowed him to build a giant data set of fish size and nutrient output. He did this by catching hundreds of live fish, putting them in plastic bags for 30 minutes, and measuring the nutrients of the water before and after, he said.

The results showed that nitrogen output was related to fish size, and that carnivorous fish peed more phosphorus than small herbivorous fish.

What's more, models created by Allgeier and his colleagues will help researchers estimate how much waste specific species and sizes of fish release, he said. "It's remarkable how robust the models are just from knowing fish size and species," he said.

The study was published online Aug. 16 in the journal Nature Communications.

Original article on Live Science.

For the first time, scientists are getting a glimpse of how microscopic marine creatures move about in their underwater environment and interact with one another on the ocean floor.

The new imaging system — an underwater microscope and computer interface that can be operated by a diver — was developed by the Scripps Institution of Oceanography's Jaffe Laboratory for Underwater Imaging at the University of California, San Diego.

Dubbed the Benthic Underwater Microscope (BUM), it is the first microscope to image the seafloor and its inhabitants at such a small scale. [Photos: The Secret Lives of Corals]

Researchers used the microscope to observe tiny coral polyps in the Red Sea and in Maui. They reported in a new study that recording the miniscule organisms' activities offered unprecedented insight into the how the polyps live and behave.

Life on a smaller scale

Coral reefs can be massive, stony structures that host a diverse community of marine life. But the individual coral polyps that build them are small, soft-bodied animals — miniature mouths ringed with tentacles. To understand how reef colonies confront and manage threats such as pollution and climate change and competitors such as algae, it's important to not only look at the reef system, but to investigate the activity of the polyps themselves, according to study co-author Tali Treibitz.

Treibitz, an assistant professor at the School of Marine Sciences at the University of Haifa in Israel, told Live Science that BUM made it possible to observe what the 1-millimeter-long (0.04 inches) polyps were doing while still in their natural environment — how they fed, competed with other corals and responded to colonization by harmful algae.

BUM's design allows the scientists to maintain a distance of at least 2.5 inches (6.4 centimeters) from the polyps they are observing, so they don't disrupt them. A soft, pliable lens — similar to the lens in the human eye — allows the microscope to adjust its focus quickly. And an extremely short exposure time of less than 1 microsecond helps eliminate motion blur.

The equipment requires two underwater housings. One holds the microscope — optics and illumination — while the other holds the computer, a hard drive for image capture and a screen that shows the microscope's images to the diver in real time.

For the team's research, it typically took about 5 to 10 minutes to set up the microscope, according to study co-author Andrew Mullen, a doctoral student of ocean science at the Scripps Institution of Oceanography.

"Once it was set up, the diver could take a series of images very quickly," Mullen told Live Science. [Images: Colorful Corals of the Deep Barrier Reef]

The underwater microscope is even powerful enough to capture images of the single-celled algae that live inside corals, Mullen added.

"Kissing" corals

During the Red Sea dives, BUM captured an unusual behavior among the coral polyps that had never been observed before: Polyps in the same colony that were close together would embrace each other at night. Scientists aren't sure what the purpose of this behavior is, but they describe it as "kissing."

Divers also noted instances of aggressive behavior between colonies of different coral species.

BUM observations in Maui targeted reefs that suffered bleaching in 2015, when higher-than-normal ocean temperatures triggered the corals to expel the symbiotic algae that lent them their color. Bleached reefs can regain their algae allies and recover if conditions improve, but the 2015 bleaching event left the Maui reefs vulnerable to harmful algae.

The scientists used BUM to observe the algae invasion on the reef as it happened, and learned that the algae followed a specific growth pattern, taking hold in areas of the reef between the coral polyps, likely because those regions of the reef were thinner and more vulnerable after bleaching.

"People care about these huge ecosystems," Mullen said. "But if you want to take care of these ecosystems, you have to know about the things that are happening at the small scale that are impacting them."

Treibitz added that BUM could prove to be an important tool for understanding large marine communities like coral reefs, by offering a window into the processes of their tiny builders.

"With our microscope, you can image the polyps live and in situ — seeing everything they're doing to survive — and give a wider view of what's actually happening," she said.

The findings were published online today (July 12) in the journal Nature Communications.

Original article on Live Science.

Benthic Underwater Microscope

The Benthic Underwater Microscope (BUM) is positioned to study coral competition.

Stylophora

In situ image of the coral Stylophora taken using the 5x objective lens, in Eilat, Israel. The image is an enhanced DOF composite formed from a focal scan z-stack. The field of view is 1.7 x 1.4 mm.

Benthic Underwater Microscope image

In situ image acquired using the 3x objective lens, in Eilat, Israel. The image is an enhanced DOF composite formed from a focal scan z-stack. The field of view is 1.7 x 1.4 mm.

Rhopalaea

In situ image of the pharyngeal basket of the transparent ascidian Rhopalaea idoneta, taken using the 5x objective. Rhopalaea idoneta is a filter feeder which uses the mesh of the pharyngeal basket to capture plankton. The field of view is 1.7 by 1.4 mm.

First phases of bleaching

Porities coral with different levels of zooxanthellae loss. When few or no zooxanthellae can be seen in the coral the polyps have a translucent appearance.

More damage

While translucent, the polyp structure and tentacles remain intact and visible, indicating that the polyp is still alive.

Beyond repair

Bleached Porities polyps being colonized and overgrown by turf algae.

Coral competition

In situ image of competition between the corals Platygyra (left) and Stylophora (right) recorded in situ. The Platygyra emitting its mesenterial filaments. The field of view is 17 x 14 mm.

Pocillopora Coral Under White Illumination

Image of the coral Pocillopora damicornis recorded in the lab. The image is an enhanced depth of field composite formed from several images taken at different focus planes. The small dots inside the polyps are individual zooxanthellae. The field of view is 4.2 x 3.5 mm.

Pocillopora Coral Competition

Fluorescent image of the coral Pocillopora damicornis taken in the lab. The image was formed by exciting the coral with blue light and using a filter to block any returning light in the blue portion of the spectrum. Two sources of natural fluorescence can be seen. Red fluorescence is produced by chlorophyll in single-celled symbiotic algae, Symbiodinium, living inside the coral. Green fluorescence is emitted from tips of the coral tentacles by a fluorescent protein naturally produced in the coral. The image is an enhanced depth of field composite formed from several images taken at different focus planes, the field of view is 4.2 x 3.5 mm.

Before you go to the beach this summer, you may want to check where the sharks are hiding: In the largest survey of sharks around the world, scientists have visited 100 reefs and collected more than 5,000 hours of underwater footage, revealing the locations with the most sharks — and where they're scarce.

These preliminary results suggest that some spots are teeming with the ocean predators, while other heavily fished areas of the ocean have little or no sign of the marine animals. 

For this huge undertaking, known as the Global FinPrint, researchers are using baited remote underwater video (BRUV) equipment to capture images of sharks and other animals as they pass by. By the end of the three-year project, which began last year, the researchers hope to have cataloged sharks and rays around 400 reefs. [In Photos: Underwater Cameras Capture World's Sharks]

Nearly a quarter of the more than 500 species of sharks swimming in the world's oceans are threatened with extinction, according to the Smithsonian. Data collected from this census could help scientists and policymakers better protect at-risk shark populations, the researchers say.

#BRUVbattle

At least 30 species of sharks and rays have been observed in the first 100 reefs, according to FinPrint lead scientist Demian Chapman, an associate professor of marine sciences at Florida International University (FIU).

"Our international team has deployed more than 5,000 BRUVs and collected more than 5,000 hours of footage," Chapman said in an emailed statement.

In some locations, sharks and rays were so common that the researchers started a competition on Twitter, using the hashtag #BRUVbattle, for the most sharks in a single screenshot. The team from Australia currently holds the record, with 12 gray reef sharks caught on camera along Jarvis Reef in the Pacific Ocean.

We're flipping out just like #BRUV that got flipped by this great #hammerhead. We've reached 1000 followers on FB! pic.twitter.com/W6ZcgakrBk

— Global FinPrint (@globalfinprint) May 13, 2016

The scientists even caught some silly antics under the sea: A hammerhead seemed to try to eat, or perhaps defeat with its mouth, one of the cameras, eventually flipping it over; and a feisty crab got into a scuffle with a hungry octopus, as both creatures tried to gobble up the BRUV bait. Apparently, the crab won, a Twitter video revealed.

Shark hotspots

Locations like Australia's Great Barrier Reef and the Bahamas showed an abundance of sharks and rays, Chapman said.

However, cameras rolled for hours in some more heavily fished locations with little or no signs of sharks. Researchers collected more than 100 videos off the coast of Malaysia, for instance, and only one shark was caught on camera. Videos in Jamaica resulted in not a single shark sighting.

"Some of these areas are really overfished, and we don't have the big predators playing the ecological roles they used to," Mike Heithaus, a marine biologist at FIU and a FinPrint researcher, told Live Science. "We probably need to come up with regulation that will help rebuild those populations."

As more data are collected, the researchers will know where the populations are healthy and where they're threatened, Heithaus said. Also, scientists can better understand "when, where and how" sharks and rays are vital to the health and function of coral reef ecosystems.

Global FinPrint will share the census data on an open-access database, but Heithaus said the project won't stop at data collection.

"The next step in this project, after we do the science, is to really work with governments, local communities, to formulate plans for the management and conservation of these animals and their habitats," Heithaus said.

Original article on Live Science.

Scientists have discovered a huge coral reef system lurking beneath the muddy waters of the Amazon.

The network of coral reefs, which is about 600 miles (1,000 kilometers) long and is home to a hidden ecosystem of colorful and bizarre creatures, was found at the mouth of the Amazon River, where freshwater from the river empties into the briny waves of the Atlantic Ocean.

Extraordinary expedition

The Amazon River is the world's largest river by volume, harboring 20 percent of the freshwater on Earth. It is also home to a stunning array bizarre and as-yet-undocumented creatures. [The World's 10 Longest Rivers]

Patricia Yager, a marine scientist at the University of Georgia and lead investigator of the River-Ocean Continuum of the Amazon project, and her colleagues had originally set sail on the expedition to sample species from the mouth of the Amazon River, according to a statement.

But one of the team members, biologist Rodrigo Moura from the Universidade Federal do Rio de Janeiro, had seen a published study from the 1970s "that mentioned catching reef fish along the continental shelf and said he wanted to try to locate these reefs," Yager said.

So the team set out on a hunt for mysterious reefs. The first obstacle was finding out exactly where the researchers of that past study had done their surveying. The 1970s journal article didn't have GPS coordinates, so the team went to the general area and used sound waves to create pictures of the river bottom. Then they pulled up seafloor samples to confirm the presence of the reef.

Intricate web of life

It turned out the reef was home to a hidden carnival of life not evident at the murky water's surface, including loads of reef fish species, a wide variety of sponges (as well as sponge-eating fish), algae and, of course, coral species.

"We brought up the most amazing and colorful animals I had ever seen on an expedition," Yager said.

The team then returned to the site in 2014 to do a full catalogue the rainbow of reef species and the reef's characteristics, which they reported April 22 in the journal Science Advances.

The reef changes over its extent. At the southern edge of the reef, sea creatures get more sunlight, and the reef is dominated by traditional coral and creatures that use light to make food.

"But as you move north, many of those [species] become less abundant, and the reef transitions to sponges and other reef builders that are likely growing on the food that the river plume delivers. So the two systems are intricately linked," Yager said.

Yet the amazing Amazon reef system was endangered almost from the moment of its discovery. It turned out that oil exploration is planned on top of the reef, while ocean acidification and warming threatens the coral reefs just as it does throughout the world's oceans, Yager said.  

Follow Tia Ghose on Twitter and Google+. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

12 Outstanding Artificial Reefs to Visit

Even the biggest coral reefs begin as a handful of tiny, free-swimming coral larvae — they attach themselves to rocks or other hard surfaces, and over time, expand and increase in number. As they grow, their exoskeletons form vast, hardened colonies that not only house the coral and the algae that lend them their color, but also provide refuge for many species of fish, anemones, sea stars and other marine animals.

However, not all reefs emerge from naturally occurring objects on the sea bottom. Human-made structures are frequently introduced into marine environments to serve as foundations for corals to attach to and form reefs, and for other underwater creatures to use for shelter.

Shipwrecks are commonly designated as artificial reefs, but decommissioned military vehicles, subway cars, oil rigs and even original sculptures also provide places that corals and other creatures can build into a home.

Here are some of the spectacular locations where human-made objects found new purpose underwater as artificial reefs, forming sanctuaries for a diverse range of sea life and providing unique experiences for divers and underwater photographers.

Tamar Reef, Israel

Diving enthusiasts have visited the Red Sea for decades to enjoy its marine diversity — 800 species of sea life and hundreds of types of corals, according to the Israel Ministry of Foreign Affairs.

Installed in 2007, Tamar Reef — the Red Sea's first artificial reef — is a joint project maintained by scientists and administrators from Israel and Jordan. It was introduced to relieve overstressed natural reefs in the area, and to help re-establish depleted marine life and raise conservation awareness.

USCGC Duane shipwreck, Key Largo

If you're planning a trip to the Florida Keys, a dive to see this behemoth underwater structure may be for you: The U.S. Coast Guard Cutter Duane, decommissioned on Aug. 1, 1985, and sunk as an artificial reef on Nov. 17, 1987, measures 329 feet (100 meters) long and rests upright on the sea bottom at an average depth of 95 feet (29 m). Many of its interior rooms were left open for divers to explore. Advanced Dive Certification is recommended, according to the Upper Keys Artificial Reef Foundation website, and guided dives are offered for less experienced explorers.

Thunderbolt shipwreck, Florida, USA

Shipwreck connoisseurs will find much to discover in this popular Florida Keys' diving destination, which has accumulated more than three decades' worth of coral and algae growth. Originally dubbed the USAMP Major General Wallace F. Randolph upon its construction in 1942, this former mine planter was renamed "Thunderbolt" after being repurposed in the 1960s for lightning strike research. It was later donated to the Florida Keys Artificial Reef Association and sunk as a reef on March 6, 1986.

So grab your scuba gear! Located beneath 120 feet (27 m) of water just 4 miles (6 kilometers) off Marathon, this reef could make for a fascinating dive.

The Silent Evolution, Mexico

For divers visiting Cancun, Mexico, this astounding underwater sculpture exhibit is a must-see destination. Life-size and eerily life-like concrete casts of 400 individuals comprise sculptor Jason deCaires Taylor's art installation, "The Silent Evolution," part of an exhibition in the underwater museum Museo Subacuático de Arte. Installed in 2012, the installation covers 502 square yards (420 square meters), and was described by the artist as "art intervention as growth." Over time, the faces and bodies of the figures metamorphose as they are colonized and covered by algae, starfish and corals.

Redbird Reef, Delaware, USA

Next stop, biodiversity! The end of the line for a number of retired New York City subway cars was the bottom of the ocean off Delaware. Beginning in 1995, donated "Redbird" cars created a new artificial reef that currently hosts numerous small fish like sea bass and summer flounder, as well as larger predators like sharks, striped bass and tuna. Fishing opportunities abound for anglers, while divers can share commuting woes with the fish that inhabit the cars.

High Island A389A, Gulf of Mexico, USA

Lots to explore in the Gulf of Mexico, which hosts many naturally occurring reefs. But don't stop there: All five states bordering the Gulf — Texas, Louisiana, Mississippi, Alabama and Florida — host artificial reef programs to supplement these habitats. High Island A389A, an oil and gas production platform colonized by corals and other undersea animals, is located inside East Flower Garden Banks National Marine Sanctuary boundaries. Divers can expect to see many of the same species of reef fishes that are common in Caribbean dive sites.

Building an artificial reef

Reefs abound off this glorious Florida beach. On April 6, 2013, 62 modules were deployed off the coast of Mexico Beach to form an artificial reef. Since 1997, the Mexico Beach Artificial Reef Association (MBARA) has installed more than 150 artificial reefs, using them to conduct research and educate the public on the importance of reef systems in coastal communities. In addition to offering dive opportunities, MBARA hosts fishing tournaments and provides education workshops on artificial reefs for adults and children.

Tanks for all the fish

In 2009, retired army tanks and armored personnel carriers joined the tugboats, barges, subway cars, bridge debris and other concrete structures that make up more than 45 man-made reefs in waters off South Carolina. Once their surfaces are colonized by corals, barnacles, marine worms, sponges and algae, the reefs attract even more marine life — fish, sea urchins, mollusks and crustaceans — seeking food and shelter.

The South Carolina Department of Natural Resources maintains 42 sites in its offshore reef program, and recommends May through October as the months when water temperatures and weather conditions are most suitable for scuba diving.

Hermenegildo Capelo shipwreck, Ocean Revival Park, Portugal

"All divers are welcome" to this shipwreck off the coast of Portugal, according to the Ocean Revival project website. Frigate Ex-NRP Hermenegildo Capelo weighs 2,700 tons and measures 335 feet (102 m) in length. Acquired by the Portuguese navy in 1968, it saw 37 years of service and was scuttled on June 15, 2013. Rui Guerra's striking image of the frigate's steering wheel received a commendation from the Underwater Photographer Award of the Year 2016 competition. What are you waiting for?

Reef Balls

Called Reef Balls, spherical concrete structures are specifically designed for installation as artificial reef foundations, and have been used to foster habitats for corals and other sea life at thousands of marine locations. A unique shape provides space for fish to find shelter, while the balls' rough texture encourages corals to take hold. Divers can expect to encounter Reef Balls in a number of artificial reef sites around the world, as approximately 500,000 Reef Balls have been deployed in 3,400 artificial reef and beach restoration projects across more than 70 countries, according to the group's website.

Ashkhabad shipwreck, North Carolina, USA

Suitable for novice to intermediate divers (according to Discovery Diving), the Russian tanker Ashkhabad sank to the ocean floor off North Carolina in 1942. It was torpedoed by a German U-boat and then finished off with a round of explosives that sent it to its watery grave. Resting in 55 feet (17 m) of water, Ashkhabad measures 401 feet (122 m) in length and is currently home to colorful corals as well as other local sea life such as barracuda, grouper and stingrays.

Koh Tao reef cubes, Thailand

In 2015, more than 2,000 concrete cubes were installed around Koh Tao island, in one of the largest artificial reef projects in the Gulf of Thailand. Each cube frame weighs approximately 1.2 tons (1,089 kilograms), and flotation bags were attached to them so that divers could maneuver them into position underwater, according to the New Heaven Reef Conservation Program (NHRCP), which engaged in the artificial reef construction. NHRCP was founded by New Heaven Diving School, an organization that offers certification for advanced divers, training for divers interested in marine conservation, and instruction for beginners. Happy diving!

Australia's Great Barrier Reef corals are in trouble.

The northern part of the world's largest coral reef ecosystem is experiencing "the worst mass bleaching event in its history," according to a statement released Tuesday (March 29) by the Australian Research Council.

Documented by the National Coral Bleaching Taskforce (NCBT) in aerial surveys, observations of more than 500 coral reefs spanning 2,485 miles (4,000 kilometers) showed that the majority of reefs were undergoing extensive and severe bleaching.

"Almost without exception, every reef we flew across showed consistently high levels of bleaching, from the reef slope right up onto the top of the reef," said Terry Hughes of the NCBT, calling the surveys "the saddest research trip of my life." [Worst Coral Reef Bleaching on Record for the Great Barrier Reef | Aerial Video]

Bleaching happens when corals are exposed to stresses such as warmer-than-average waters for prolonged periods of time. The corals respond to the stress by expelling the algae that provide them with their color, which makes the corals look like they've been bleached white. Bleaching can be fatal for corals if the stress is too intense, or if it continues for too long and the algae are unable to recolonize them.

Ecosystem at risk

Australia's Great Barrier Reef (GBR) covers 134,364 square miles (348,000 square kilometers), making it larger than the U.K., Switzerland and the Netherlands combined, according to the Great Barrier Reef Marine Park Authority. Recognized as a World Heritage Area in 1981, the reef contains 400 types of coral and hosts 1,500 types of fish and 4,000 mollusk species, as well as other marine life such as large green turtles and dugongs ("sea cows").

The GBR experienced bleaching events in 1998 and in 2002, but the current mass bleaching is much more severe, experts are saying. Rebecca Albright, a marine biologist with the Carnegie Institution for Science in Washington, D.C., has studied the GBR since 2011. Albright told Live Science that 95 percent of the GBR's northern reefs are currently showing signs of extreme bleaching, compared with 18 percent that experienced bleaching in 2002.

Even the more robust corals are affected, Albright said, another sign that this event is particularly serious. She cautioned that it's still too early to assess the long-term impacts of bleaching on the corals, though estimates of coral mortality anticipate losses of about 50 percent.

Two factors are responsible for stressing the corals, Albright said: climate change, which is driving ocean temperatures upward, and a strong El Niño  — a cyclical climate event associated with warmer-than-average sea surface temperatures in the tropical Pacific. And with El Niño conditions expected to extend through 2016, that doesn't bode well for the corals' recovery.

"Corals are sensitive to not only the anomaly in temperature — how high it goes — but also the duration of that exposure," Albright told Live Science. "This kind of perfect storm of all these factors coming together makes this a catastrophic scenario right now." [Images: Colorful Corals of the Deep Barrier Reef]

A global event

But what's happening to the GBR is only part of the picture. A global bleaching event prolonged by El Niño is currently underway — "the longest coral die-off on record," according to a statement released by the National Oceanic and Atmospheric Administration (NOAA) on Feb. 23.

Mark Eakin, coordinator of the NOAA Coral Reef Watch program, told Live Science that the event, which began in 2014 in the Pacific, could linger through 2017.

"We consider it a global bleaching event if it's widespread in all three of the major ocean basins — Indian, Atlantic and Pacific," he said. Eakin described current reports of bleaching that extend over half of the Southern Hemisphere, with severe bleaching in New Caledonia, Fiji and southern Indonesia, as well as in the GBR.

Even fast-growing corals take decades to develop, so damaged reefs will need time before they're restored to their former level of health, Eakin said.

And recovery time may be in short supply. Global bleaching events have been expanding their reach and increasing in severity since the first event was documented in 1998, Eakin told Live Science.

"We’re seeing prolonged high temperatures that cause bleaching coming back repeatedly. We're seeing areas that have seen high temperatures for two to three years in a row. There's no time for corals to recover," he said.

The 1998 global bleaching event was associated with a strong El Niño — the strongest on record — but as ocean temperatures rise, even a mild El Niño can trigger a devastating effect on the world's corals. And the global bleaching event that's underway right now began in 2014, before the current El Niño was active, Eakin said.

For the GBR, in spite of the extreme bleaching there may yet be some hope for its recovery. The upper part of the reef that sustained the most damage was in very good shape beforehand, which should improve its prospects for "bouncing back," according to Albright.

"And the lower two-thirds of the GBR is still in very good shape — not a lot of bleaching in those areas. So a lot of people are holding on to that as another piece of hope," Albright said.

"It’s really just a matter of whether or not we get another bleaching event in the next 10 years that would impede recovery," she added.

Follow Mindy Weisberger on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science.

There's a new soft and squishy robot in town, and it's ready for some serious underwater business.

Meet "Squishy Fingers," a new remotely operated vehicle designed to delicately grab and take samples of coral. The ROV, described in a Jan. 20 study in the journal Soft Robotics, will help researchers collect specimens from deep underwater reefs without damaging the corals' fragile bodies.

"If we're going to go down and study these systems, then we should be as gentle as we possibly can," said study co-senior author David Gruber, an associate professor of biology at Baruch College in New York City and a National Geographic emerging explorer. [Marine Marvels: Spectacular Photos of Sea Creatures]

Until now, coral researchers used clunky and rigid ROVs originally developed for the oil and gas industries. These vehicles' stiff arms were made to do heavy work, such as turning pipes off and on, rather than plucking tiny organisms off a coral reef.

"These arms can generate lifting and gripping forces up to 500 lbs.-force [227 kilograms-force] and are not optimal for delicate specimen collection," the researchers wrote in the study.

Enter soft robotics expert Robert Wood, study co-senior author and a professor of engineering and applied sciences at Harvard University.

"Rob was looking at the [ROV], and he was like, 'Oh my God, that's how you guys are collecting stuff? That doesn't look very effective,'" Gruber recalled.

So the two assembled a team and got to work designing "Squishy Fingers," an ROV with a soft but firm grasp. The team took inspiration from sea creatures, such as the tube worm and the snake (which can wrap itself about things).

The final fingers are largely made of memory foam, silicone rubber, fiberglass and Kevlar fibers.

Humans can't safely scuba dive beyond 330 feet (100 meters) of water, so it's important that Squishy Fingers can dive deeper and retrieve hard-to-reach creatures, Wood told National Geographic. So far, the joystick-controlled squishy robot has successfully completed a dive at about 0.6 miles (1 kilometer) depth, but the researchers hope to design an upgrade that can reach 3.7 miles, or 3,168 feet (6 km), Gruber said.

Eventually, the team hopes to create a "Squishy Arms" robot that has a greater capacity to collect deep-sea organisms, he added.

The specimens collected by these squishy ROVs will help researchers study the genomes and proteins of mysterious underwater plants and animals, as well as identify new species, Gruber said. 

"It's one thing to just see them, but you can't identify a new species just by looking at it or just by taking a new picture," Gruber told Live Science. "Sometimes you need to take one sample, or even get things like a vein biopsy sample in order to sequence its genome."

Follow Laura Geggel on Twitter @LauraGeggel. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

NASA is about to get up close and personal with Earth's corals: The space agency will use airplanes and water instruments to survey these delicate structures and capture the most detailed views ever of the planet's corals.

Corals are crucial to Earth's ecosystem, but they are typically studied only occasionally, during diving expeditions. This means that many of the world's reefs have never been surveyed. Yet coral reefs host one-quarter of all ocean fish species, shelter shorelines from storms and are a source of food for millions of people.

The new NASA campaign is aptly named CORAL (short for COral Reef Airborne Laboratory), and aims to assess the condition of these vulnerable ecosystems and to collect data on the size and quality of the reefs. [Images: Colorful Corals of the Deep Barrier Reef]

"Right now, the state of the art for collecting coral-reef data is scuba diving with a tape measure," Eric Hochberg, CORAL principal investigator and a scientist at the Bermuda Institute of Ocean Sciences in St. George's, said in a statement. "It's analogous to looking at a few trees and then trying to say what the forest is doing."

As part of the campaign, CORAL researchers will visit the Great Barrier Reef and other reefs in Australia, as well as reefs in Florida, Hawaii, Palau and the Mariana Islands.

The scientists will use an airborne instrument called the Portable Remote Imaging Spectrometer (PRISM), which was created at NASA's Jet Propulsion Laboratory in Pasadena, California. The spectrometer will be used with on-site instruments in the water to monitor the reef's condition.

One of PRISM's tasks will be to record the ratio of algae to reef on a coral. When corals die, algae numbers typically increase, and the spectral signatures of corals and algae show up differently in the spectrometer, NASA said.

Based on the limited data available so far, scientists think 33 percent to 50 percent of Earth's coral reefs are degraded or dead. Some reef scientists think that reefs could all but vanish by the middle of the century.

Though it will be comprehensive, the three-year CORAL campaign will cover only 3 percent to 4 percent of the world's reefs.

"Ideally, in a decade or so, we'll have a satellite that can frequently and accurately observe all of the world's reefs, and we can push the science — and, most importantly our understanding — even further," Hochberg said.

Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

For the past year, the world’s corals have been getting increasingly pummeled by climate change. Now with El Niño kicking ocean heat into overdrive, much of the world’s oceans have turned deadly for the world’s corals.

On Thursday, the National Oceanic and Atmospheric Administration (NOAA) announced a global coral bleaching event. This year joins the ranks of 1997 and 2010 as the only times on record that bleaching has occurred in all three of the world’s oceans that support coral at the same time.

All three global bleaching events have occurred in El Niño years, and the climate phenomenon definitely has a role to play. But the ever-rising temperatures underwater and above due to climate change are the biggest reason corals are currently dying off across a 4,600-square mile area in the Atlantic, Indian and Pacific oceans.

Great Barriers: Reefs First Line of Coastal Defense What Will Survive in Hot, Acidic Oceans? Acidic Oceans Could Quiet Coral Reefs

“The baseline temperature has heated so much that reefs are no longer able to cope with what's normal in El Niño years,” Richard Vevers, director of the XL Catlin Seaview Survey, said. “These events are going to become more and more common as climate change goes on. Coral bleaching is such a spectacle; the equivalent above water would be a rainforest turning white.”

Once ocean waters warm past a certain threshold, coral begin to die off because they can’t support the algae that sustain them. The result is ghostly forests of white coral.

Without the protection of reefs, small islands lose their first line of defense against storm surge as well as ecosystems that support fisheries and tourism for more than 500 million people. Reefs also support about a quarter of all marine species despite covering less than 0.1 percent of the world’s oceans. In addition to bleaching, ocean acidification and wild sea level swings due to El Niño are also conspiring to cripple reefs.

The current spate of bleaching began in 2014, a year that saw record warmth on both land and sea. Temperatures have since continued to climb in 2015 (and 2016 is already looking pretty hot, too), resulting in coral dying off everywhere from the Caribbean to Hawaii to the Indian Ocean’s Coral Triangle.

The die-off around Hawaii has been particularly worrisome with more than a third of the island chain’s coral experiencing bleaching since 2014, including areas that have never seen bleaching occur before. Mark Eakin, the coordinator of NOAA’s Coral Reef Watch, said that by the year’s end, more than 60 percent of the state’s corals could suffer the same fate. All told, 95 percent of the corals in the U.S. are expected to be exposed to bleaching.

Because of the magnitude of the strong El Niño and the growing climate change signal in the oceans, Eakin said that NOAA is issuing an extended forecast for reefs through May for the first time. It is not a good forecast for reefs.

“The worst part about it is if you look at Indian Ocean, its showing that the thermal stress is going to be worse in 2016 than 2015,” Eakin said.

NOAA scientists have been working with Catlin Seaview Survey to monitor reefs before, during and after bleaching events to see the impacts occurring in real time. Vevers and his team have been using high resolution, panoramic photography that provides valuable scientific information on how different species are affected by heat as well as powerful images that show the impacts of climate change on some of the world’s most delicate ecosystems.

As much as the efforts are helping scientists identify the impacts climate change is having on corals, it’s also helping them identify areas and species that can survive in ever-warming waters.

“One thing that imagery provides us with is information on places where we should be putting more investments and taking more action to protect reefs that may be resilient to climate change,” Eakin said. “The other is by demonstrating the rate at which we’re losing resources. It provides very valuable information on what we stand to lose by not addressing climate change and the importance of addressing climate change and doing it quickly. We stand to lose a lot.”

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Originally published on Climate Central.

Emily Darling is an associate conservation scientist at the Wildlife Conservation Society (WCS), where she coordinates a global coral reef monitoring initiative across Kenya, Madagascar, Fiji, the Solomon Islands, Indonesia and the Caribbean. For University of North Carolina at Chapel Hill, she is also leading a global database of reef-building coral communities to evaluate climate refuges on coral reefs. Follow Emily on Twitter at: @EmilySDarling. She contributed this article to Live Science's Expert Voices: Op-Ed & Insights.

Coral reefs are some of the most fascinating places on our planet. The colorful and biodiverse tropical ecosystems are home to more than 25 percent of marine species, yet corals face grave threats today from climate change, overfishing, pollution and disease that jeopardize the underwater architecture of reefs — and the fisheries they support. 

Those fisheries are critical to the livelihoods and nutrition of millions of coastal peoples around the world: More than 450 million people live within 37 miles (60 kilometers) of a coral reef and depend on coral need fisheries for food and income that 80 percent of the world's coral reefs are overfished, challenging the sustainability of the fisheries they support, according to the International Coral Reef Alliance Network (ICRAN). 

Diving deeper

For me, pursuing a career as a marine biologist began in a fish market. When I was eight years old, my family lived in Indonesia for a year. Visiting the chaotic, noisy and smelly fish markets, I was fascinated by the silver, blue and green shimmering fishes and the translucent piles of squid and octopus tentacles — they revealed an underwater world hidden from me as a child.

That fascination stayed through my undergraduate research in biology at Queen's University in Kingston, Canada, where I took an three-week field course to study coral reef fish on a remote atoll in Belize — and learned how to scuba dive. I learned that overfishing, climate change, pollution, disease and invasive species threaten these ecosystems I could now see during dives in the ocean. Still completely enamored with fish upon graduation in 2005, I was awarded a Jean Royce Fellowship for women in science to learn about managing one threat to coral reefs: overfishing. 

Soon after, I found myself in Kenya on the doorstep of the WCS Coral Reef Conservation Project, where I learned about coral reef fisheries management from conservationist Tim McClanahan. 

Over the next four months, I bumped along coastal roads filled with potholes to interview fishermen and measure the catch they were landing. In the evenings, my colleagues and I would pore over spreadsheets with 10 years of fisheries data collected along the Kenyan coast. When the power went out, which was most nights, we had to resort to working by headlamp. By day, we would sit on the beach for hours as we waited for the fishermen to sail in with the tides. As we waited, my friend and collaborator Christina Hicks taught me Swahili, and about the families that depended on these fish for their livelihoods — and the best way to fry up the catch. 

Later that year, McClanahan, Hicks and I published our first paper together, in which we showed that removing destructive fishing gear (like illegal beach seine nets that damaged corals and caught small, juvenile fish) could rebuild local fisheries. [One Fish, Two Fish, But is It True Fish? (Video )]

Communities of people saving communities of reefs

I have now returned to WCS, contributing to research programs on coral reef fisheries and climate change. Our goal is to strengthen community management of coral reef fisheries in a warming climate, giving local communities the tools to manage their own fisheries sustainably and improve climate resilience. In collaboration with our global partners, we are striving conserve coral reef biodiversity and support sustainable small-scale fisheries and livelihoods. 

It is gratifying to work towards aligning science and resource management with critical human needs. I hope to inspire a new generation of fisheries scientists in the countries where we work, so that young girls might take inspiration from the remarkable biodiversity in their fish markets as I did, and take a dive into the undersea world of marine conservation.

Read more about women in conservation from WCS in the following Live Science articles:

• How Two Women Brought a Sea Change to Conservation (Op-Ed)
• Developing World Boasts Leading Women Conservationists (Op-Ed)
• A Crocodile Hunt, Redefined, in Southeastern Cuba (Op-Ed)
• Stepping Up Conservation in Fiji — in Stilettos (Op-Ed)

Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook, Twitter and Google+. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Live Science.

Aquarium enthusiasts and people who work in aquarium stores should be aware that some types of coral produce dangerous toxins that can be hazardous to your health, according to a new report.

The report, from the Centers for Disease Control and Prevention, describes 10 cases of toxin poisoning in Alaska between 2012 and 2014 that were linked to zoanthid corals, a common type of coral in home aquariums. Some zoanthid contain high levels of palytoxin, a toxin that can cause life-threatening symptoms if people touch, inhale or ingest it, the CDC said.

"Many aquarium store employees and marine aquarium hobbyists are not aware of palytoxin as a potentially serious hazard associated with handling some zoanthid corals," the report said. "General recommendations on coral handling and decontamination practices would be helpful for hobbyists, commercial coral growers, and the public health and clinical provider communities." [Images: Colorful Corals of the Deep Barrier Reef]

Public health officials in Alaska began an investigation into toxin poisoning after a man was hospitalized — and two of his housemates experienced serious symptoms — following the introduction of zoanthid corals into their home aquarium. The patients had fever, weakness, cough and muscle pain, and a reported a bitter metallic taste in the mouth. All three patients recovered within two days.

Although none of the patients had direct contact with the coral, they appear to have inhaled the toxin, the researchers said. The toxin could have been released when some of the coral polyps broke off during the transfer of the coral to the aquarium. The corals can also produce aerosolized toxins when people use hot water or scrub to remove zoanthids from tanks, the researchers said.

The store that sold the patients their coral also reported that multiple staff members had experienced similar symptoms in the recent past, including a metallic taste, cough, joint pain, flank pain, fever and feeling cold during the night. One staff member said he or she had experienced symptoms of toxin poisoning nine times.

The shop owner also told health officials that in 2012, a man and his pregnant wife were hospitalized after the husband cleaned a fish tank with zoanthids. Although the wife did not help with the cleaning, she walked by the area several times. The couple were in the intensive care unit for several days. The wife delivered her baby, but the infant was three months premature. The child survived, and did not appear to suffer from adverse health effects, although the husband reported that he still had lung problems two years later, the report said.

The toxin from zoanthids can be neutralized by soaking the coral for 30 minutes in household bleach and water. In addition, contaminated items should be soaked in diluted bleach before disposal, the report said. Activities that could produce aerosols should be undertaken with caution, they said. When decontaminating areas that may have been exposed to the toxin, patients were advised to use protective equipment, including a face mask, goggles and overalls.

The study was published in the Aug. 14 issue of the CDC journal Morbidity and Mortality Weekly Report.

Follow Rachael Rettner @RachaelRettner. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

Deep in the Red Sea, beyond the reach of most scuba divers, coral reefs are putting on a glowing, colorful show, scientists have discovered.

Researchers found the radiant corals more than 160 feet (50 meters) below the surface of the Red Sea, which separates Africa from the Arabian Peninsula. At these depths, corals stay mostly in the dark. Yet, despite their limited exposure to light, they glow brightly in fluorescent yellow, fiery orange, forest green and mustard yellow, in researchers' photographs. These luminous rainbow-colored corals could be used to develop new tools for viewing microscopic objects in medical research, researchers said.  

The corals' glow comes from fluorescent pigments, noted study co-author Jörg Wiedenmann, a professor of biological oceanography at the University of Southampton in the United Kingdom. [Take a video tour of the Red Sea's glowing corals]

"These fluorescent pigments are proteins," Wiedenmann said in a statement. "When they are illuminated with blue or ultraviolet light, they give back light of longer wavelengths, such as reds or greens."

Corals that live at depths of between 100 feet and 330 feet (30 to 100 m) are called mesophotic corals because of the limited amount of light that reaches them. The word "mesophotic" translates to "meso" for "middle" and "photic" for "light." There are limited data on their distribution, quantities and way of life. Typically, special equipment — such as autonomous underwater vehicles and remotely operated submarines — is needed to access the reefs.

"Advances in technical diving have enabled us to explore coral communities from these deep waters," said study lead author Gal Eyal, a Ph.D. candidate in the zoology department at Tel-Aviv University in Israel.

"Since only the blue parts of the sunlight penetrate to depths greater than 50 metres [164 feet], we were not expecting to see any red coloration around," Eyal said in a statement. "To our surprise, we found a number of corals showing an intense green or orange glow. This could only be due to the presence of fluorescent pigments."

Colorful corals are most often associated with shallow waters — the amount of sunlight they receive determines how much pigment they produce. In deeper waters, however, some corals can produce pigment independently from the amount of sunlight that manages to penetrate their habitat, according to researchers. These corals can switch from their natural green tinge to a mature red color without light.

The researchers suggest that the fluorescent pigments in the corals fulfill a specific biological function, though the specifics are unknown. The fluorescent pigment is what makes the corals especially useful for developing advanced medical imaging tools, the researchers said.

For instance, in lab experiments, the corals' florescent proteins could attach to specific living cells and track their movement. Red fluorescent proteins, which emit longer-wavelength light, are easier to detect because they can more easily penetrate cells, according to the study.

"Their optical properties potentially make them important tools for biomedical imaging applications, as their fluorescent glow can be used to highlight living cells or cellular structures of interest under the microscope, Wiedenmann said. "They could also be applied to track cancer cells or as tools to screen for new drugs."

The detailed findings were published Wednesday (June 24) in the journal PLOS One.

Elizabeth Goldbaum is on Twitter. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science

On a remote Pacific island not much bigger than Manhattan, there are ancient pyramids built out of living coral. New evidence reveals that these tombs could be up to 700 years old — much older than experts had previously thought.

The royal tombs are tucked away in an artificially built ancient city called Leluh just off the mainland of Kosrae, a Micronesian island. Leluh was home to Kosraean high chiefs (as well as some lower chiefs and commoners, too) from about 1250 until the mid-1800s, when foreign whalers, traders and missionaries started to arrive on the island.

With impressive canals and walled compounds built from basalt, Leluh is often considered a companion city to the more famous Micronesian settlement of Nan Madol, on the nearby island of Pohnpei. While the tiny islets of Nan Madol were built on top of a coral reef, at Leluh, coral was actually incorporated into the construction material of many buildings, including the royal tombs. [8 of the World's Most Endangered Places]

"Today, the ancient tombs of the royal burial complexes are one of the few parts of the ancient Leluh site that remain intact," said Zoe Richards, a coral expert at the Western Australian Museum and lead author of a new study detailing the findings. "Much of the historical site is overgrown by the tropical forest and has succumbed to hundreds of years of tropical weather and tidal inundation, and some parts of the site have been dismantled and reused in modern construction."

These tombs, also known as saru, stand about 6.5 feet (2 meters) tall, and they're shaped like frustums (pyramids with their pointy tops lobbed off). Historical sources indicate that when a Kosraean king died, he would be rubbed with coconut oil and wrapped in mats and cords to be buried in the saru for up to three months. The king's bones would then be exhumed, cleaned and reburied in a hole on the nearby reef, Richards and her colleagues wrote.

Because these burials were not permanent, not much was left behind in the tombs to help archaeologists today determine the age of these structures. The bones of a 50-year-old man and a dog were found in one of the tombs, known as Inol-1, but a radiocarbon dating of those skeletal remains showed that this burial took place relatively recently, sometime between 1824 and 1850.

To get a more precise estimate of the age of the tombs, Richards and her colleagues turned to the building material itself. They collected 47 chunks of coral from three saru — Inol-1 and two others, named Lūrūn and Bat — and subjected these samples to uranium-thorium dating, a technique used to determine the age of calcium-carbonate materials like coral.

The results showed that all three tombs could have been built as early as the 1300s, the researchers said.

"The results of this study lend support to oral histories and other archaeological work on Kosrae suggesting an earlier construction, occupation and use of Leluh," Richards told Live Science in an email. "It also better supports Leluh's place in the region, not only as a rival to Nan Madol on Pohnpei, but also as a hub of political and economic activity throughout this part of the Pacific."

Some of the corals actually dated back thousands of years, which means that the people of Leluh were using coral fossils and rubble to fill out the tombs' walls and line the crypts, the researchers said. However, Richards and her colleagues think most of the corals used in the tombs' construction were plucked from live reefs surrounding Kosrae at low tide.

"To extract and translocate the amount of coral used to build the saru, as well as the structures and walls throughout Leluh, would have required a highly structured social order that could organize and demand significant labor and logistical support from the population," Richards said.

The findings were published today (March 13) in the journal Science Advances. 

Follow Megan Gannon on Twitter. Follow us @livescience, Facebook & Google+. Original article on Live Science.

Lily Whiteman is a media officer for the U.S. National Science Foundation (NSF). She contributed this article to Live Science's Expert Voices: Op-Ed & Insights.

Some good news for coral reefs: In 2014, President Obama expanded the Pacific Remote Islands Marine National Monument in the central Pacific from about 87,000 square miles to 308,000 square miles. The Monument "is the largest marine protected area in the world and an important part of the most widespread collection of marine life on the planet under a single country's jurisdiction," according to the National Oceanic and Atmospheric Administration (NOAA).

This area sustains a diversity of species, including some of the most pristine coral reefs in the world , as well as a diversity of fish species, shellfish, marine mammals, seabirds, land birds, insects and vegetation not found anywhere else.

Payback from protection

Fishing, energy exploration and other activities are prohibited in the Monument. Among the Monument's protected corals are expansive shallow coral reefs and deep coral forests, including some corals that are 5,000 years old.

The expansion of the monument is promising in light of benefits that may be provided by marine protected areas (MPAs). An MPA is a coastal or offshore marine area that is managed to protect natural and/or cultural resources.

In the accompanying video, Paul Sikkel, of Arkansas State University, discusses some of the possible successes of the MPA system in the Philippines. This system was developed back in the early 1970s, when reef fisheries were left virtually unmanaged, and destructive fishing practices, often organized by large commercial fishing companies, ran rampant throughout the Philippines — a cluster of 7,107 islands that harbors more than 1,700 reef species and about 9 percent of global coral reef area. [The 10 Most Pristine Places on Earth ]

Power to the people

To help protect its marine resources, the Philippines established at least 985 MPAs covering almost 5 percent of coastal municipal waters. To a large degree, the Philippine MPAs are now co-managed by local communities and local governments along with the national government. This partial de-centralization of authority helps give responsibility for MPA management to those who depend on their ecological health the most: coastal communities.

The Philippine MPAs still fall short of the national goal for coverage area, and conservation enforcement problems remain. Nevertheless, some evidence suggests that the Philippine community-based management system may have generated some conservation victories.

For example, a study published in 2010 showed that species richness of large predatory reef fish increased fourfold over a 14-year period in one Philippine MPA and 11-fold over a 15-year period in another Philippine MPA. The study also showed that as species richness increased in complexity within one of the MPAs, this type of complexity also increased within neighboring fished areas — evidently because of a spillover effect from the MPA.

But even while MPA status may provide protection from local threats, such as pollution or anchor damage, MPAs may remain vulnerable to global threats, such as climate change, which cannot be controlled at local levels.

In the accompanying video, Sikkel also discusses a new mechanism that may be damaging coral reef ecosystems in the Caribbean.  Sikkel identified this potential mechanism through his National Science Foundation-funded research on the relationships between parasites and their host fishes in Caribbean reefs.

Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook, Twitter and Google+. See the ScienceLives archive. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Live Science.