When you picture a desert, you probably imagine a vast, empty landscape far from any water. But surprisingly, some of the driest places on Earth lie right beside the ocean. Both the Atacama, in Chile, and the Namib, in southern Africa, stretch along coastlines. So how did these extreme deserts form in places bordered by so much water?

There are three main factors that allow deserts form next to oceans, David Kreamer, a hydrologist at the University of Nevada, Las Vegas, told Live Science: how air moves vertically, how air moves horizontally, and how mountain ranges interact with air moisture.

If you look at a world map, you'll notice that most deserts sit above or below the equator. That's because the equator receives the most direct sunlight and causes the air to warm and rise. As the warm air rises, it creates a low-pressure system — a region where atmospheric pressure is lower than its surrounding area, Kreamer explained. Any moisture in the air cools and condenses into clouds and rain. That's why the regions along the equator are home to lush forests, like the Amazon.

That rising air spreads outward and sinks between 20 and 40 degrees north and south of the equator, and suppresses cloud formation — which explains why there are so many deserts along the subtropical belt, such as the Sahara and the Kalahari.

Then, there is the horizontal movement of air across the planet. Near the equator, trade winds blow from east to west. These winds tend to drop moisture on the eastern sides of continents, leaving their western sides drier. In the case of the Namib, for example, when it does rain, that rain doesn't fall in the desert itself but rather in the mountains to the east, said Abi Stone, a physical geographer at the University of Manchester in England.

Cold ocean currents also play a role. The air that's being blown across the cold current cools on contact with it and picks up some of its moisture, and because of the coldness, the air becomes quite stable. "We kind of envisage packages of air, in some ways, like a balloon, because they don't totally mix, but the balloon skin is really flexible, and they can expand and contract," Stone told Live Science. "The cold air won't tend to do much of that expansion." Without any convection, the pack of air becomes trapped, unable to rise. "But what it can do is hold some moisture, and at the low level, that can get blown on land, and you end up with quite foggy environments at the western part of those coastal deserts," Stone said.

The presence of mountains impacts the dryness of these deserts as well. When moist air is forced over a mountain range, it cools and drops rain on the windward side, Kreamer explained. By the time the air descends on the leeward side, much of its moisture is gone, creating a rain shadow, or an area by the mountains that gets reduced rain. For instance, Seattle, which is located on the western side of the Cascade Mountains, gets an average of 39.3 inches (99.8 centimeters) of rain a year, while Yakima, located on the eastern side of the Cascades, gets an average of 8 inches (20.3 cm) of rain annually.

In the case of the Atacama, Kreamer said, "the wind that comes in South America drops a lot of rain on the east side over the Amazon, and then it hits the Andes. The Andes sap more water off the wind and then right along the coast of South America on the west side, where Chile is," leaving the Atacama exceptionally dry.

These factors give coastal deserts unique characteristics that aren't found in other deserts. They tend to have cooler and more stable climates than inland deserts do, and they're home to plants and animals that have evolved special traits to capture moisture. In the Namib, for example, some beetles harvest water by pointing their butts toward the foggy air.

"People have studied what that surface looks like to make more effective fog nets," Stone said. "There are some amazing creatures."

The formation of polar deserts, like most of Antarctica and the northernmost parts of the Arctic, is driven by many of the same factors as warm coastal deserts. The temperature also plays a role, since the air is so cold in these parts of the world that it can't hold moisture. "In the case of Antarctica, the strong winds and ocean current around the continent is effective at blocking weather systems traveling onto the continent," Stone said.

Equator quiz: Can you name the 13 countries that sit on Earth's central line?

India's Thar Desert has become 38% greener over the past 20 years, driven by a combination of climate change and agricultural expansion, according to a new study.

The past two decades have seen more people living in this desert and changing the landscape, making it more agricultural and urban, which is part of the reason why the desert has become greener, researchers said. The other piece of the puzzle is climate change, which has caused increasing monsoon precipitation in the region.

The Thar Desert, also called the Great Indian Desert, spans 77,000 square miles (200,000 square kilometers) in northwestern India and southeastern Pakistan. Although many deserts throughout the world are facing worsening droughts, the Thar Desert has become a hub of urban and agricultural growth, making it the most populated desert in the world with more than 16 million residents.

"Increased water and energy availability have led to expansion in agricultural and urban areas with a considerable increase in crop yields in the region," study co-author Vimal Mishra, a civil engineer at the Indian Institute of Technology Gandhinagar, told Live Science in an email. "There is no other desert in the world that has experienced increases in urbanization, agriculture, and precipitation during the recent period,"

The new study, published April 3 in the journal Cell Reports Sustainability, analyzed satellite data from 2001 to 2023. Mishra and his team found that the desert became, on average, 38% greener during this time, with more vegetation visible in satellite images.

Related: Why are deserts dry?

To understand why exactly greening is happening, the researchers also looked at historical records of population expansion in the Thar Desert, irrigation infrastructure, and climate models.

The findings show the Thar Desert's greening has been driven primarily by more rain during summer monsoon seasons — a 64% rise in precipitation overall — and secondly by irrigation infrastructure bringing groundwater to the surface outside of the monsoon season.

The authors suggest that sustainable management of water resources in the Thar Desert can help this area adapt and continue to sustain its growing population. However, warmer temperatures may threaten the 16 million people who live in this desert, and overuse of groundwater for irrigation can deplete resources, the researchers noted.

Sustainable water management practices, drought-resistant crops, adaptations to rising heat and renewable energy must all be part of future development in the Thar Desert, the researchers said.

The increased monsoon rainfall could also mean more flooding, as climate models project this increased rainfall will happen in bursts in extreme weather events, which can damage homes and buildings in the desert.

However, if managed and adapted to, the increased rain could also enable people and agriculture to flourish in the region. Researchers behind a separate study projected that even more of the landscape will become green by the end of the 21st century.

This change would boost food security in the region but could threaten the native biodiversity of desert-adapted specialist species and traditional methods of nomadic farming. The scientists warned that the need to preserve these aspects of the desert environment must be taken into consideration as development continues.

Deserts can take many forms — including sweeping sand dunes, rocky canyons, sagebrush steppes and polar ice fields. But they're united by one thing: a lack of rainfall. Generally speaking, anywhere that gets less than 10 inches (25 centimeters) of rain a year counts as a desert, said Lynn Fenstermaker, an ecologist at the Desert Research Institute in Reno, Nevada. 

Of course, that lack of rain means deserts are, famously, dry. But why do some places on Earth get much less rain than others? In other words, why are deserts dry?

Global air circulation patterns are the biggest reason, Fenstermaker said. Solar energy hits Earth most directly at the equator, heating the air and evaporating moisture from it. That warm, dry air rises and travels toward the poles. It tends to sink again around 30 degrees latitude, Fenstermaker explained. This circulation pattern is called a Hadley cell, and it drives the trade winds, which fueled early exploration of the globe by seafaring explorers. It's also why many of the world's biggest deserts — such as the Sahara and the Gobi in the Northern Hemisphere, and the Kalahari in the Southern Hemisphere — are at these midlatitudes.

Related: Could the Sahara ever be green again?

But the story is more complicated than that. Wind patterns interact with topography to influence where deserts are found. For example, air that sweeps in from the ocean and hits a mountain range will release its moisture as rainfall or snow onto the slopes as the air rises. But by the time the air crosses the mountains and sinks down the other side, it's dry. In California, for example, the Mojave Desert sits in the rain shadow of the Sierra Nevada, Fenstermaker said.

Sometimes, inland areas are drier because they're so far from a large body of water that air blowing in has lost all its moisture by the time it arrives, said Andreas Prein, an atmospheric scientist at the National Center for Atmospheric Research in Boulder, Colorado. This is the case with the Gobi Desert in Central Asia, which is also shielded by the Himalayas. 

On the other hand, coastal doesn't always mean wet. Cold ocean currents colliding with the air moving into the coast can create fog. When that fog moves over land, the moisture stays in the air instead of falling as rain. This can create deserts that abut the ocean, such as the Atacama in Chile, one of the driest places on Earth.

Not all deserts are hot, either; parts of the Arctic and Antarctic count as deserts. Cold air can't hold moisture as well as warm air does, Prein said. So the frigid temperatures at the poles lead to very little rainfall, even though ample water is stored in the ground as ice.

As global climate patterns shift, so do deserts. For example, thousands of years ago, the Sahara was covered in grasslands and tropical forests. And today, climate change is reshaping the boundaries of deserts around the world.

"The Hadley cell is expected to spread north and southwards because of climate change," Prein said, expanding the zone that's ripe for desert formation. Warmer temperatures could accelerate the shift by increasing evaporation of water and drying the air even further. Beyond just rainfall, it's the balance of precipitation and evaporation that defines a desert, Prein added.

"Globally, with warming, what we're anticipating is that we're going to have more evaporation, and just expansion of existing desert regions," Fenstermaker noted.

Human pressure on landscapes is contributing, too. Cutting down trees to plant crops removes native vegetation, and some research suggests that deforestation in the tropics is reducing precipitation. If more water evaporates instead of being held in the soil by plants, a feedback loop nudges landscapes drier and drier. Semiarid areas on the fringes of existing deserts are particularly vulnerable.

"It's often compounding factors that help deserts to grow," Prein said. "It's not only human activity, or climate change, or the natural climate variability, but it's everything on top of each other that brings ecosystems over the tipping point."

The mesmerizing honeycomb patterns found in salt deserts such as Badwater Basin in California's Death Valley and Salar de Uyuni in Bolivia have perplexed tourists and inspired sci-fi movie-makers for decades. Scientists, too, have struggled to elucidate the mechanism behind the iconic shapes.

Now, physicists think they've finally solved this natural puzzle.

"The fantastic landscape demands an explanation," Lucas Goehring, an associate professor of physics at Nottingham Trent University in England, said in a statement. "What we've shown is that a simple, plausible explanation is there, but hidden beneath the ground."

The answer lies in the groundwater beneath the salt crust, according to a study published Feb. 24 in the journal Physical Review X. In the study, researchers describe how layers of salty and less salty water circulate up and down in donut-shaped currents, which are squeezed together horizontally to form the regular pattern.

Previously, scientists suggested that the cracks and ridges form as the salt crust expands and dries out, bending and fragmenting under the strain.

Now, the researchers note that previous attempts to understand the iconic landscape didn't account for the uniform size of the hexagons, which are always 3 to 6 feet (1 to 2 meters) across, wherever in the world they are found.

Related: What's the largest desert in the world? 

The new study confirms the widely accepted idea that the geometric patterns are formed by a mechanism rooted in basic thermodynamics, similar to the movement of hot and cold water in a radiator or in a pot of boiling water. "The surface patterns reflect the slow overturning of salty water within the soil, a phenomenon somewhat like the convection cells that form in a thin layer of simmering water," Goehring said.

Salt deserts aren't as bone-dry as they seem. Beneath the salt crust sits a layer of extremely salty water, which can be reached by digging with your hands. The water evaporates in the hot summer months, leaving only a blanket of salt, some of which dissolves into the next layer of water. This layer is then more dense than the one below it, and the salty water sinks in a ring that surrounds fresher, less dense water rising to replace it. The water evaporates and leaves a salt residue, which dissolves into the top water layer again. The cycle repeats itself to form what scientists call a convection roll.

Research on salt deserts has focused either on these subsurface currents or on the crust. The new study argues that the two features interact and mirror each other to form the tessellations. Where the dense, salty surface water sinks, salt accumulates on the crust to form ridges. The salt crust grows more rapidly around the edges of each hexagon because it is in contact with saltier water than the middle.

Normally, a convection roll would adopt a circular donut shape. Because there are so many of them packed closely together on a salt flat, however, the rolls are squeezed against each other to form hexagons, the researchers said.

The authors present a convincing explanation for the striking pattern, Stuart King, a researcher at the University of Edinburgh in Scotland who did not participate in the study, told Live Science in an email. "It is well known that hexagonal patterns arise from convection and evaporation processes, [but] this paper connects that with the penetrative convection of the porous layer underneath, which seems very plausible as a wider mechanism driving the whole salt formation."

The scientists say their work was driven purely by curiosity. "Nature presents us with an obvious and fascinating puzzle that stimulates our curiosity and thereby prompts us to solve it — even without any direct further possibility of application in mind," study first author Jana Lasser, a postdoctoral researcher at Graz University of Technology in Austria, said in the statement. 

Deserts are not easy places to call home. Broiling in the day, frigid at night, and lacking ample water, these landscapes test their inhabitants. The creatures that call deserts home have adaptations to help them survive and thrive in these harsh conditions. Many of these creatures never need to drink and have skin or scales that enable them to hoard what little water they require; some have evolved to move and be active solely at night to avoid the punishing sun. Here are 15 of the strangest animals found in deserts around the world.

Fennec fox

Desert animals don't get much cuter than fennec foxes (Vulpes zerda). These teeny canids are smaller than domestic cats, measuring 14 to 16 inches (35.6 to 40.6 centimeters) long, not including their tails, but they sport enormous ears that can grow to be 4 to 6 inches (10.2 to 15.2 cm) long. These ears help the foxes shed heat and listen for prey under the sand. When the foxes catch the sound of rodents, insects or other small animals they predate, they use all four paws to dig out their quarry in a shower of sand, according to the Smithsonian National Zoo.

Fennec foxes are well-adapted for life in African and Arabian deserts. Their pale fur camouflages them against the sand; it also grows on the bottoms of their feet to give them traction while running in the sand and protects their feet from the hot desert surface. When air temperatures rise, the foxes can pant up to 690 times per minute to cool down. Fennec foxes also dig elaborate burrows to escape the sun in the hottest part of the day.

Screaming hairy armadillo

Perhaps less cute than fennec foxes — but no less well-adapted to their desert environment — are screaming hairy armadillos (Chaetophractus vellerosus). These armadillos really do scream; when threatened, they make a terrible cry that sounds similar to the wails of a newborn human baby. Research published in 2019 suggests that these screams are designed to startle predators, or to attract other predators to the scene, perhaps distracting an attacker and enabling the armadillo to get away. 

Screaming hairy armadillos are small, weighing only 1.9 pounds (0.86 kilograms). They live in the Monte desert of Argentina, Bolivia and Paraguay, preferring spots with loose, sandy soil where they can dig burrows, according to the Smithsonian National Zoo. The armadillos rarely need to drink. Their kidneys are highly efficient, and they get most of the water they need from the plants they eat. It's a waste not, want not environment in the desert, so screaming hairy armadillos are opportunistic eaters — they also consume insects and small animals such as lizards and rodents.

Hairy desert scorpion

Among the many scorpion species that call deserts home, the hairy desert scorpion (Hadrurus arizonensis) is a standout. These sorpions can measure between 4 and 7 inches (10.2 to 17.8 cm) long, according to Utah's Hogle Zoo, making them North America's largest scorpions. Though they are a drab olive-green color, hairy desert scorpions fluoresce under ultraviolet (UV) light. No one knows exactly why scorpions fluoresce, but the best way to find these shy nocturnal predators is to take a UV light into the desert on a summer night, when they tend to be most active. 

Hairy desert scorpions are found in North America's Sonoran and Mojave deserts, as well as in Nevada and Utah. When looking to mate, male and female hairy desert scorpions lock pincers in a mating dance that looks more like a wrestling match. In fact, if the male does not flee quickly after depositing his sperm, he might find himself becoming his mate's next meal. 

Females gestate their young for six to 12 months, live-birthing up to 35 babies that piggyback on their mother's carapace until they're large enough to hunt on their own. Fortunately for humans, desert hairy scorpions would rather flee than sting, and their venom is relatively weak. For most people, the sting is similar to a bee's sting.

Harris's hawk

Harris's hawks (Parabuteo unicinctus) are oddities in the falcon world. These impressive red-winged raptors sometimes hunt in packs, working together to pursue their prey around bushes, thickets and the saguaro cactuses of Arizona's Sonoran desert. The birds eat lizards, other birds and small desert mammals such as kangaroo rats and ground squirrels. When they catch large prey, they'll share the meat with their fellow hunters, according to the conservation nonprofit Audubon.

These birds also often work in groups to raise their young. Two males may mate with a single female, and the trio work together peacefully to raise any ensuing hatchlings. Hawk siblings help each other, too; an older brood from earlier in the season may stick around to bring food to younger broods.

Desert ironclad beetle

The desert ironclad beetle (Asbolus verrucosus) is a tank of an insect. Its powder-blue color comes from a waxy coating that helps the beetle retain moisture in the dry Sonoran desert. The bumps on the beetle's shell give it an armored appearance that is even tougher than it looks. The ironclad beetle subfamily is known for its ultra-strong exoskeleton — it’s so strong, these beetles can shrug off being stepped on by a human, according to the University of Wisconsin, Milwaukee. 

Desert ironclad beetles are also known as "death-feigning beetles" for their defensive behavior in the face of threats. When alarmed, the beetles roll over and play dead, according to the Cincinnati Zoo and Botanical Garden. They eat plants and decaying organic matter, and — like many desert denizens — rarely, if ever, need to drink.

Sand cat

A softer, fuzzier desert denizen is the desert sand cat (Felis margarita). It is the only cat species that makes its home in true desert environments. Desert sand cats are found in the Sahara desert, the Arabian Peninsula, Turkmenistan, Kazakhstan and Uzbekistan. Though they look remarkably similar to fluffy domestic kitties, sand cats are elusive and rarely seen by people. They're secretive and difficult to track, according to the International Society for Endangered Cats (ISEC) Canada. Researchers who tried to observe these animals in the wild found that the cats' fur-lined paws left no tracks, and their light-colored coats made them challenging to spot. What's more, the cats crouched low and closed their eyes against searchlights at night, hiding their reflective retinas. 

Sand cats are stealthy hunters and are able to kill snakes as well as desert rodents and lizards. Their mating call sounds like a dog's bark.

Desert long-eared bat

Once dubbed "the hardest bat in the world," the desert long-eared bat (Otonycteris hemprichii) is found in North Africa and the Middle East. What earned this bat species that nickname? Well, its main diet is scorpions. 

Desert long-eared bats hunt scorpions by falling onto them out of the sky and wrestling the venomous arachnids into submission. The bats are unbothered by the multiple scorpion stings they often receive in the process, according to research from Ben-Gurion University of the Negev in Israel. Ben-Gurion University researchers also found that desert long-eared bats can switch the settings on their sonar, using one type of echolocation to seek out ground-dwelling prey like scorpions and another type to hunt down flying insects.

Pink cockatoo

Colorful birds are often found in lush, tropical rainforests and are scarce in arid regions — except if that region happens to be in Australia’s interior. One of the continent's most beloved bird species is the pink cockatoo (Lophochroa leadbeateri), which ekes out an existence in the semi-arid and arid Australian Outback. 

Identifiable by its showy orange-and-yellow crest and its blush-shaded body, the pink cockatoo is divided into two subspecies: one found in western-central Australia and other in the east, according to the Australian Museum. These pretty birds live off seeds and insects. They mate for life, according to the Australian Foundation for National Parks and Wildlife (FNPW), and they can be found prancing on tree branches, bobbing their heads up and down to attract mates.

These iconic Australian birds have a variety of names and nicknames, according to FNPW. They're also known as Major Mitchell’s cockatoos (after the early English explorer who wrote about them for a global audience), as well as Leadbeater’s cockatoos, desert cockatoos, cocklerinas, chockalotts and — adorably — wee jugglers.

Sidewinder

Perhaps nothing screams "desert" like the image of a sidewinder rattlesnake undulating over a sand dune, leaving behind bizarre curved tracks. Sidewinders (Crotalus cerastes) can slither at speeds of up to 18 mph (29 km/h) using their strange sideways crawl — even across loose sand, according to the Smithsonian Channel.

Sidewinders are ambush hunters. They bury themselves in sand, leaving only their eyes peeking upward. When a lizard happens by, they snap forward and spring the trap. These snakes strike in the blink of an eye, injecting venom that ]attacks both the blood and the nervous system of unwary prey. 

Sidewinders are found in the southwestern United States and northwestern Mexico. They can be recognized by the protruding horn-like structures shading their eyes, which may keep sand from obscuring their vision.

Desert pupfish

Fish in the desert? Desert pupfish (Cyprinodon macularis) are small, silvery fish that can survive remarkably well in parched conditions. Pupfish have evolved to thrive in water that flows through arid regions. They're found in California's Salton Sea and its tributaries, and in waterways along the lower Colorado River in Mexico. 

These fish require a high degree of resiliency to survive in a desert's meager or brackish water sources. Special adaptations enable pupfish to survive despite  conditions that would be deadly for most fish, according to the California Department of Fish and Wildlife. Pupfish can live in water ranging from fresh to 70 parts-per-thousand salt (most of the ocean is between 34 and 26 parts-per-thousand salt). They can live in water as cold as 40 degrees Fahrenheit (4.4 degrees Celsius) and as hot as 108 degrees F (42.2 C). They can even live in water as poorly oxygenated as 0.1 parts-per-million (ppm) oxygen (most warm-water fish require 5 ppm oxygen in their water to survive, according to Florida's Center for Aquatic and Invasive Plants). 

Despite their toughness, desert pupfish are endangered in California, threatened by the introduction of non-native species and habitat loss.

Thorny devil

No list of weird desert animals would be complete without a nod to lizard-kind. And no nod to lizard-kind would be complete without mentioning the thorny devil (Moloch horridus), the sole species in the genus Moloch, named for an ancient, sacrifice-demanding god worshipped by the Caanites and mentioned in the Hebrew Bible. Thorny devils are only found in Australia. They grow to be just over 8 inches (21 cm) long from nose to tail and are covered with sharp spines that serve as a defense against predators. 

Thorny devils also have two heads — really. One is a false head, a protuberance that sits on top of the devil's neck. When threatened, a thorny devil will lower its real head, presenting the false head as a decoy. Thorny devils also have a distinctive jerky walk that may confuse predators, according to Bush Heritage Australia.

As intimidating as thorny devils may look, they're really only a danger to ants, which they lap up by the thousands with their sticky tongues, according to Bush Heritage Australia. These desert denizens "drink" through their skin, collecting dew and moisture from sand with tiny channels between their scales. These straw-like channels, which direct the precious drops to the lizards’ mouths, are just one example of the creative hydration mechanisms that keep animals alive in the driest places on Earth.

Saharan silver ant

Saharan silver ants (Cataglyphis bombycina) get their name from their silky, silvery coats. Yes, these ants have hair. 

Unlike most desert animals, Saharan silver ants forage in the middle of the day, when the Sahara can reach temperatures of up to 158 degrees Fahrenheit (70 degrees Celsius). This strategy helps them avoid predators but requires them to cool themselves very efficiently. A 2015 study in the journal Science found that the ants' silver hairs are shaped to help them reflect and radiate both sunlight and heat across the electromagnetic spectrum, keeping the insects cool.

Elf owl

Adorable elf owls (Micrathene whitneyi) are only the size of a sparrow, making them the world's smallest raptors, according to The Cornell Lab. Found in the southwestern United States and Mexico, these owls make their nests in old woodpecker holes in large saguaro cactuses or in trees. They avoid the desert heat during the day and instead use their incredible eyesight and hearing to hunt at night, pouncing on prey such as scorpions, insects and centipedes, according to the Arizona-Sonora Desert Museum.

Tarantula hawk

Tarantula hawks aren't birds: They're a group of predatory wasps that prey on — you guessed it — tarantulas. These wasps are found around the world, but several species that dwell in the United States live in the desert southwest. Pepsis thisbe, for example, is a species of tarantula hawk that lives at the Grand Canyon. Wasps of this species have bright-orange wings and can grow up to 2 inches (5 cm) long, according to the National Park Service.

What really makes these wasps unique, though, is their habit of using tarantulas as living food for their larvae. Mother tarantula hawks paralyze tarantulas with their venom, carry them back to their nests and seal them in, laying their eggs in the spiders' abdomens. As the larvae grow, they feed on the paralyzed tarantulas, saving the vital organs for last.

Greater bilby

Looking a bit like a cross between a shrew and a bunny, greater bilbies (Macrotis lagotis) are found in deserts and grasslands in Australia. These cute creatures are about the size of a housecat. They spend their days in tunnels that they dig out of the dry Australian soil, and they spend their nights foraging for food such as termites, tubers and grubs. Like many desert animals, bilbies get all the moisture they need from their food, according to Bush Heritage Australia.

Originally published April 12, 2022 and updated Jan. 27, 2023.

From vast expanses of scorching sands to immense ice sheets, deserts can take different forms. But which hot and cold deserts are the most immense on the planet? And which types of life can survive in these extremely dry places?

To answer this record-setting question, it's important to consider what exactly makes a desert a desert. According to Jonathan Wille, an Antarctic meteorologist and climatologist at the University of Grenoble in France, any region that sees less than 9.8 inches (25 centimeters) of precipitation per year qualifies as a desert. 

When all such regions are considered, Antarctica qualifies as Earth's largest cold desert, and the Sahara is the largest hot desert. 

"At 14.2 million square kilometers [5.5 million square miles], Antarctica is the largest desert in the world," Wille told Live Science. "Some regions of Antarctica, like the McMurdo Dry Valleys, are believed to have not received any precipitation in 14 million years." This epic lack of precipitation is due in large part to cold temperatures, nearby mountains that block clouds, and strong winds that suck moisture from the air.

Even for a desert, this region is exceptionally parched. According to scientists who are part of the National Science Foundation's LTER (Long-Term Ecological Research) project in Antarctica, the McMurdo Dry Valleys have no snow or ice except for the few lakes that are permanently iced over. But it isn't completely barren. There are microbes, mosses and lichens that can tolerate the dry deep freeze.

Related: Why do deserts get so cold at night?

Wille, who led a 2021 study in the journal JGR Atmospheres looking into Antarctic precipitation, thinks this frozen desert is often overlooked. Although far inland areas of Antarctica are mostly devoid of life, he said that more organisms, such as petrels and penguins, set up shop where they can snap up fish and other sea creatures from the frigid waters, and seals sometimes come ashore.

Predictably, the Sahara desert, which stretches across northern Africa, is the stark opposite of Antarctica. It measures 3.55 million square miles (9.2 million square km). But although some may see it as a wasteland, it's surprisingly diverse. This desert reveals a variety of both geographical features and life-forms, according to André Vicente Liz, a doctoral candidate at the University of Porto in Portugal. 

"The Sahara presents obvious geographic characteristics that largely contradict the established perception, primarily a highly diverse [landscape] and different… types [of materials beneath the surface] but also considerable spatial variability in climate," Liz told Live Science.

The diverse landscapes of the Sahara include not just its famous sand dunes but also rock terrain, salt flats, mountains and savannas that may even have water. There have been drastic shifts in the desert's climate in the past, which has led to vast biodiversity in different regions of the desert. Liz led a 2022 study in the Journal of Biogeography exploring Saharan animal species that had previously not been given much attention. 

In hot deserts, cold-blooded creatures thrive because their body temperatures adjust to the temperature of their surroundings as they move from scorching sunlight into cool burrows. Liz has observed many small lizard species that have adapted especially well to the arid environment. Some reptiles and amphibians can also hibernate during times of drought. Besides lizards, snakes, scorpions, beetles and ants, and even a few frogs and toads that live in rock pools, the Sahara is also home to mammals and birds. Antelope, camels, cheetahs, ostriches and desert foxes are just some of the warm-blooded animals that can survive in the Sahara.

There are some areas, such as rock pools known as "gueltas," where biodiversity is especially high because they act as refuges for species that had to flee their habitats due to a sudden, intolerable change in weather. In the face of climate change, Liz and his colleagues are studying these regions closely to find out what makes them good spots for survival.

"These areas are known as biodiversity 'refugia' and are especially interesting for conservation planning in the current context of climate emergency, where they can play a key role as climatic buffers," he said.

So deserts can be deceptive places that only look lifeless until something crawls or slithers out. They may be dry, but that means anything but monotonous.

Death Valley is more than earning its morbid name this weekend, as temperatures in the California desert reached a near-record-breaking 130 degrees Fahrenheit (54.4 degrees Celsius), according to news reports

That makes it a tie for the hottest temperature ever verified on Earth since the mercury hit 131 F (55 C) on July 7, 1931, in Kebili, Tunisia, The Washington Post reported. Though an even hotter temperature of 134 F (56.7 C) was recorded in Furnace Creek (then called Greenland Ranch) in Death Valley, on July 10, 1913, per Guinness World Records, some climate scientists say that reading was not verified, the Post said.

Rewind to nearly a year ago, on Aug. 16, Death Valley also smashed heat records with a 130-F reading, Live Science reported at the time.

Related: Hell on Earth: Take a photo tour of Death Valley

No stranger to extremes, Death Valley is one of the hottest and driest places on Earth due to the shape of the valley and its location relative to mountain ranges. For instance, as storms move inland from the Pacific Ocean, they pass over mountain ranges on the eastward trek; vapor-dense storm clouds hit the ranges, rise up and cool, leading to condensation and of course rain or snow. When the clouds reach the other side of the mountains, they have much less moisture, something called a dry rainshadow, according to the National Park Service (NPS). With four mountain ranges between Death Valley and the ocean, clouds tend to be parched by the time they reach the desert.

These mountain ranges also act as walls around the narrow Death Valley basin, which sits below sea level. When sunlight heats up the valley's dry surface, the radiation gets trapped by these steep "walls," the NPS said.

But Death Valley is not the only spot suffocating under a heat wave. Heat alerts will affect more than 30 million people in the western U.S. where triple-digit temperatures are forecast through the weekend, CNN reported.

The National Weather Service has issued "very high" heat alerts — meaning everyone in these areas faces health risk from the heat — for much of California, Nevada, Arizona and Utah, CNN reported.

The "oppressive heat wave" across the western U.S. is the result of a so-called heat dome, or a ridge of high pressure that's trapping hot air close to the surface while preventing any possible precipitation, the NWS said in an advisory.

"Widespread high temperatures of 110 [F] and above are forecast for the Southwest deserts as well as the central California valleys," the NWS said. "Highs in the 100s are likely across the Great Basin and into the upper 90s for the interior Pacific Northwest."

Some relief could be on the way, though. A cold front is moving south from Canada and could cool off Montana on Monday (July 12), the NWS said. And a pocket of cool air is moving east from the Pacific, and may provide a bit of relief to parts of northern California.

Originally published on Live Science.

Temperatures in Death Valley, California, hit a scorching 122 degrees Fahrenheit (50 degrees Celsius) Tuesday (June 15), short of the all-time record for this spot at the lowest elevation in North America but more than 10 degrees hotter than the average high temperature at this time of year.

The broiling temperatures were part of a broader heat wave across the American Southwest and West this week. On Tuesday, Denver reached a high of 101 F (38 C), the earliest in the year the temperature has topped 100 F (37.8 C) since 2013. The same day saw a sweltering 105 F (40.6 C) in Billings, Montana, a record for that date, and an all-time high of 107 F (41.7 C) in Sheridan, Wyoming, tying a previous state record. Salt Lake City also tied its highest temperature ever recorded, 107 F, on Tuesday. Southern California broke multiple heat records, with Palm Springs wilting under a high temperature of 119 F (48.3 C). Meanwhile, Phoenix, Arizona, tied its 1974 record temperature of 115 F (46.1 C).

Death Valley is known for its withering heat. The desert is situated below sea level but walled in by steep mountains, according to the National Park Service (NPS). Sunlight heats the dry desert floor, and the heat stays trapped by the surrounding rock and soil. The all-time highest air-temperature record in the world was set at Furnace Creek in Death Valley on July 10, 1913. On that day, Furnace Creek hit 134 F (57 C).

Related: Hell on Earth: Take a photo tour of Death Valley

Contributing to the current heat is a weather pattern known as a "heat dome." According to CNN, a ridge of high pressure over the western U.S. is trapping hot air close to the surface and also pushing away any potential precipitation. Sunny skies are also heating things up within the dome. And making matters worse, much of the West is currently in a deep drought. 

Drought means less moisture in the air and soil. When it's wetter, a significant fraction of solar energy goes to heating and evaporating this moisture, said Karen McKinnon, a climate scientist at the University of California, Los Angeles. In drier times, this wet "heat sink" is missing, so temperatures are free to soar.

"All of that heat is coming in, but the soils are so dry," McKinnon told Live Science. "So more of that heat is going to go into increasing temperatures instead of evaporating water."

Though Death Valley is no stranger to high temperatures, average temperatures in June are typically closer to 110 F (43.3 C) than to 120 F (48.9 C), according to the NPS. The average high temperature there in July is 116 F (46.7 C).

Temperatures in Death Valley through Friday are expected to match or exceed Tuesday's high. An excessive heat warning is in place for much of California and Arizona through Saturday.

Originally published on Live Science.

The duel is over faster than you can blink. The snake lashes out; the rat leaps into the air, kicks the snake in the head and bounces frantically away. Neither combatant gets the meal they were hoping for.

Quick-draw encounters like this happen every night in the desert and go largely unnoticed by everyone but the critters involved. But recently, a team of researchers decided to get a view of the action by recording a summer's worth of snake-on-rat attacks using high-speed cameras. The resulting footage revealed that rattlesnakes (genus Crotalus) and kangaroo rats (genus Dipodomys) are surprisingly well-matched as predator and prey. It also proved, in glorious slow motion, that kangaroo rats are furry little ninjas capable of high-kicking acrobatics that would put Bruce Lee to shame. [Photos: The Poisonous Creatures of the North American Deserts]

"Both rattlesnakes and kangaroo rats are extreme athletes, with their maximum performance occurring during these interactions," Timothy Higham, an associate professor at the University of California, Riverside, and author of two new studies about the rat/snake showdowns, said in a statement. "This makes the [high-speed camera] system excellent for teasing apart the factors that might tip the scale in this arms race." 

In a pair of new studies published March 27 in the Functional Ecology journal and the Biological Journal of the Linnean Society, Higham and his colleagues tagged a handful of sidewinders with radio transmitters, then tracked the snakes as they hunted kangaroo rats through the Yuma Desert. Over the next several months, the team recorded 32 snake-on-rat ambushes. Only about half of these strikes ended with snakebites. In analyzing the resulting slow-mo footage, the researchers figured out why.

While the sidewinders were incredibly fast, capable of vaulting from absolute stillness to reach their prey in less than 100 milliseconds (less than the time it takes to blink), the rats were even faster. The team found that the kangaroo rats could react to incoming snake strikes in as little as 38 milliseconds, sometimes jumping clear of the snake in 70 milliseconds flat.

What's more, in those 70 milliseconds, some kangaroo rats were capable of pulling off complex midair maneuvers that left the snakes reeling. One rat kicked a snake just below the head, sending the predator flying several feet away. Another rat rapidly changed its direction midair, cranking its long tail like a propeller to turn away from the attacking snake. Other kangaroo rats jumped seven to eight times their body height, launching themselves far out of harm's way.

"These lightning-fast and powerful maneuvers … tell us about the effective strategies for escaping high-performing predators," Higham said. It's likely, he added, that the kangaroo rat's keen defenses — which include exceptional hearing and explosively powerful hind legs — evolved in response to the lightning-fast speed of predators like sidewinders and owls.

You can watch more of Higham's footage on YouTube. Hopefully, it's enough to land kangaroo rats the representation in animal kung fu movies that they so clearly deserve.

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Originally published on Live Science.

A 10-mile-long (16 kilometers) lake just popped up in the middle of the hottest place on Earth.

Last week, a storm blew through Death Valley National Park in California, drenching the desert and the rest of Southern California. Now, amid the desert's echoing landscape, there sits a very misplaced lake.

The lake formed near Salt Creek, an area near the eastern edge of the park, according to SFGate. It's unclear exactly how big the lake is, but representatives from the park estimated it to be around 10 miles long. [Hell on Earth: Tour Death Valley]

Death Valley is not only the hottest place in the world, with temperatures that can reach 134 degrees Fahrenheit (57 degrees Celsius), but also the driest place in North America.

On average, Death Valley receives less than 2 inches (5 centimeters) of rain a year, according to the National Park Service. Typically, about 0.3 inches (0.76 cm) of that rainfall comes in March, but within a single day last week, 0.84 inches (2.13 cm) of rain fell in the park, according to SFGate.

This isn't much when compared with the rainfall in the rest of the country, or even the rain that this storm brought to other parts of Southern California. But unlike other areas, the desert has dry, compact soil that doesn't absorb water well, a National Weather Service meteorologist Todd Lericos told SFGate.

In the aftermath of the storm, California-based photographer Elliot McGucken captured just how bad California's famous desert is at absorbing water in his gorgeous images of the pop-up lake.

Editor's Note: This story was updated to correct the amount of rainfall that fell in Death Valley. It was 2.13 cm, not 213 cm.

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• Gallery: The Haunting Splendor of Chile's Atacama Desert

Originally published on Live Science.

Unusual bare circles in the grasslands of Australia and the Namib Desert called "fairy circles" aren't the work of termites, new research suggests.

Fairy circles are a long-standing mystery. Some scientists have argued that they mark termite nests or are the result of plants competing for scarce resources. Some say that a combination of termite and plant activity resulted in the odd splotches. But now, a new study suggests that the circles aren't the result of anything living. Rather, they're a result of weathering caused by heavy rainfall and evaporation.

Termites sometimes nest within fairy circles, study researcher Stephan Getzin of the University of Göttingen in Germany said in a statement. But there is no evidence that the termites are actually creating the bare patches. [In Photos: Mystical Fairy Circles Grace African Desert]

Mapping the circles

Getzin and his colleagues focused on the fairy circles in the Australian desert near the town of Newman. They used drones to visualize the circles from above and excavated samples from 48 separate fairy circles spread over 7.4 miles (12 kilometers). They compared the aerial photos of the fairy circles with bird's-eye views of known harvester termite nests.

"The vegetation gaps caused by harvester termites are only about half the size of the fairy circles and much less ordered," Getzin said.

When the team went digging in the circles, they found just a few "termitaria," or termite colonies. Those they did find were small, not the large, cemented dirt that prevents plants from growing over large areas and might cause the barren circles. What the fairy circles did contain, Getzin said, was a lot of clay and compacted soil. Most likely, he and his team concluded, the circles form in cycles of heavy rain and then evaporation under extreme desert heat. In unvegetated soil, they wrote in the open-access journal the Ecological Society of America, heavy rainfall washes fine clay into empty spaces within the soil, essentially sealing it off with a hard "crust" impervious to new plant growth.

"[N]o destructive mechanisms, such as those from termites, are necessary for the formation of distinct fairy circle patterns," Getzin said. "Hydrological plant-soil interactions along are sufficient."

Namibian mystery

In a second study published in the Journal of Arid Environments, Getzin and his colleague Hezi Yizhaq of Ben-Gurion University of the Negev in Israel used satellite imagery to study the patterns of fairy circles in Namibia. Most research on Namibian fairy circles has focused on the weirdly ordered, almost hexagonal pattern seen in fairly flat grassland conditions, they wrote. But in places where the topography is more varied or conditions are unusual, the fairy circles form different patterns. [Image Gallery: Amazing 'Fairy Circles' of the Namib Desert]

In drainage areas, for example, the researchers noticed oval fairy circles more than 98 feet (30 m) across. In extremely arid spots, they found very irregularly spaced circles. They also noted some "mega circles" more than 65 feet (20 m) in diameter. That research was just a pilot study, the researchers wrote, but it highlights questions about the plant and soil dynamics outside of the eye-catching, very regular fairy-circle patterns.

Getzin and his colleagues argue that to have fairy circles, a region must have very homogenous soil, just one or two plant species with particular growth patterns and a just-right balance of rain and evaporation. Those requirements could explain why fairy circles are seen in only two deserts on Earth.

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Originally published on Live Science.

Chile's Atacama Desert, the driest nonpolar desert on Earth, stretches across a roughly 600-mile (1,000 kilometers) tract of land wedged between the coastal Cordillera de la Costa mountain range and the Andes Mountains. The region boasts stunning geologic formations and has provided scientists with a wealth of research opportunities.

Old, hot and dry

The Atacama is the oldest desert on Earth and has experienced semiarid conditions for roughly the past 150 million years, according to a paper in the November 2018 issue of Nature. Scientists estimate that the desert's inner core has been hyperarid for roughly 15 million years, thanks to a combination of unique geologic and atmospheric conditions in the area. This perfectly parched inner-desert region spans roughly 50,000 square miles (130,000 square km), according to soil scientist Ronald Amundson of the University of California, Berkeley.

The Atacama is tucked in the shadow of the snow-capped Andes Mountains, which block rainfall from the east. To the west, the upwelling of cold water from deep in the Pacific Ocean promotes atmospheric conditions that hamper the evaporation of seawater and prevent the formation of clouds and rain. [Photos: The Haunting Splendor of Chile's Atacama Desert]

In other deserts around the world, like the Sahara, the mercury can soar above 130 degrees Fahrenheit (50 degrees Celsius). But temperatures in the Atacama are comparatively mild throughout the year. The average temperature in the desert is about 63 degrees F (18 degrees C).

An analogue for other worlds

The outskirts of the Atacama are home to communities of organisms that have adapted to thrive in harsh conditions. The desert's hyperarid core, however, is largely devoid of plant and animal life, save for a few strains of microbial life. Scientists hope that studying the dry, dusty conditions of the Atacama will reveal secrets about the key to life in other parts of the universe, such as Mars.

"It's not the biology that makes scientists eager to study in the Atacama Desert — it's the lack of biology," said Henry Sun, an astrobiologist at the Desert Research Institute in Las Vegas, Nevada. Researchers suspect that the microbes that inhabit the desert's hyperarid core — which slip into a sort of stasis during periods of aridity — could survive life on the Red Planet.

"It's a really interesting place to see how tenacious life is on Earth and what the climatic limits to life as we know it really are," said Amundson. 

But even the most tenacious of life-forms can be disrupted.

On average, the driest part of the Atacama receives less than a millimeter of rain each year. In rare cases, torrents of rain do fall, and life responds. In 2017, wildflowers bloomed the aftermath of a dramatic downpour. Similar rainstorms were reported in March and August of 2015.

Although the rains awakened fields of wildflowers, the floods had devastating consequences for microbial life in the desert, which has adapted to survive without water. Many microbes in the desert's hyperarid core, for instance, burst after absorbing too much rainwater.

Scientists suspect that these catastrophic storms may become more frequent as the climate changes and atmospheric conditions in the Pacific Ocean fluctuate. "Instead of making the desert drier, climate change could actually make it wetter," said Amundson.

Geologic wonderland

Much of the Atacama Desert's core is caked in thick salt deposits called playas, which can stretch for miles and are nearly half a meter thick (1.6 feet) in some places. The desert is speckled with stones that have been carried across the playas by powerful wind gusts. Alluvial fans, which are large, fan-shaped sediment deposits, connect the desert plateau with the mountains that surround it and suggest that water once flowed from the Andes into the desert.

The Atacama also features a 435-mile-long (700 km) and 12-mile-wide (20 km) swath of desert known as the nitrate belt. Nitrate minerals can be found in everything from explosives to fertilizer and were mined extensively in the Atacama before the 1930s.

Traditionally scraped from the desert's crusty surface or mined from rocky veins, nitrates were initially thought to be carried to the desert by wind-swept sea spray. Recently, scientists discovered that one of the sources for the desert's "white gold" might be ancient, evaporated groundwater.

Other materials, such as lithium, copper and iodine, have also been mined nearby; in some cases, the remnants of these mining operations can be seen from space.

A dazzling array of telescopes

At 16,570 feet (5,050 meters) in elevation, the Atacama Desert plateau may be the best place in the world to spot the solar system's secrets. To the delight of amateur astronomers, the desert sees as many as 330 cloud-free nights each year. High along the Atacama Desert plateau, an array of observatories track the celestial bodies in our solar system and beyond.

The Atacama Large Millimeter Array/submillimeter (ALMA) — a network of 66 telescopes run by an international collaboration of scientific organizations from Europe, North America, East Asia and the Republic of Chile — spies on faraway stars and the planets birthed around them.

The European Space Observatory's Very Large Telescope, helped spot the TRAPPIST-1 system of Earth-like planets, located a mere 40 light-years from Earth, and has gathered data on distant exoplanet atmospheres. This telescope, along with others, has uncovered some of the universe's most intriguing oddities and provided a wealth of data to researchers and astronomers worldwide.

Additional resources:

• Southern Night Sky Revealed: Chile's Atacama Desert (Photos)
• 8 Cool Facts About the ALMA Telescope
• Explore the Atacama, from the Medical University of South Carolina.

While the U.S. government was partially shut down for 35 days, the country's national parks suffered damage that could last generations. Now, as volunteers and conservationists assess the environmental and economic damage around the country, it seems that Joshua Tree National Park — a wonderland of spiky trees and surreal, time-sculpted rocks in Southern California — has experienced some of the worst damage.

"What's happened to our park in the last 34 days is irreparable for the next 200 to 300 years," Curt Sauer, a former superintendent of the park, said at a rally on Saturday (Jan. 26).

However, that estimate might be a bit overstated, according to one expert Live Science spoke to. While it's true that the survival of the park's Joshua trees has downstream impacts on the desert birds, insects, mammals and reptiles that rely on them for shelter and sustenance, the loss of a few individual trees is unlikely to have long-lasting effects on the park's 800,000-acre (324,000 hectares) ecosystem, Cameron Barrows, an associate research ecologist at the University of California Riverside's Center for Conservation Biology, told Live Science in an email.

Short shutdown, long-term damage

Reduced to a handful of essential staff during the shutdown, the park was unable to perform basic maintenance functions like emptying the trash or making sure the toilets didn't overflow with human waste. Meanwhile, only eight law-enforcement rangers were tasked with protecting the entire park's 1,238-square- mile-grounds (3,207 square kilometers) grounds — an expanse of land about the size of Delaware, Live Science previously reported.

During that time the security lapse, park gates were toppled and locks smashed. Rocks were defaced with graffiti, illegal campfires and vehicle traffic destroyed vegetation at some of the park's most iconic sites, and at least three of the park's ancient Joshua trees were chopped down in order to make way for illegal off-road paths. According to the National Park Service website, the average joshua tree in the park is age of the park's iconic trees is estimated to be about 150 years old.

But that doesn't necessarily mean damage to the park will take centuries to repair, Barrows said.

"Certainly, replacing one destroyed Joshua tree to the same age and condition could take [centuries]," Barrows said. "But I would be hard pressed to say the park is at greater risk of ecological damage by the loss of one tree. If it was, say, 100 acres or greater, then we are probably at a scale where ecosystem integrity is compromised." (Barrows noted that he has not been back to the park since the shutdown to see the full scale of the damage.)

More harmful to the ecosystem may be the many miles of fresh tire marks pummeled into the park's soil by off-road vehicles. That desert soil isn't just dirt or sand — it's also a complex community of vegetation and microbes that can help support every plant and animal that interacts with it.

"Vehicles creating improvised roads are a significant issue," Marinna Wagner, Masters in Landscape Architecture, told Live Science in an email. "Not only does such activity destroy existing vegetation, but the resultant soil compaction reduces soil moisture, increases runoff, causes erosion and sedimentation, and prevents seedling germination, thus slowing down the rate of ecosystem recovery even further."

National Park Service spokesperson Mike Litterst told Vice.com that soil damage like this can last for decades. So far, crews have helped repair about 20 miles (32 km) of tire tracks left during the shutdown, Vice reported, with many more to go.

These and other repairs may stress the park financially as it reckons with considerable financial losses from the shutdown. According to Sauer, the park relied on more than $300,000 in entrance fees to stay open during the shutdown, dipping into money that was meant to be used on park maintenance and the construction of a new visitors' center. In total, Sauer estimated that Joshua Tree lost about $800,000 in revenue during the shutdown.

Editor’s Note: This story was updated to add comment from Marinna Wagner.

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Originally published on Live Science.

Archaeologists in Egypt recently unearthed a grim discovery: the skeleton of a young woman dating to about 3,700 years ago who was in the final weeks of her pregnancy when she died.

And she was buried with the unborn fetus still inside her body. 

The tiny skeleton was head-down within the woman's pelvis — a position typically seen in the third trimester — suggesting that she may have died following the onset of labor, officials with Egypt's Ministry of Antiquities said in a statement on Nov 14. [The 8 Most Grisly Archaeological Studies]

An international team of experts from Yale University and the University of Bologna in Italy found the remains. They uncovered the skeletons in a cemetery at the dig site Kom Ombo in Aswan, a city in southern Egypt located about 530 miles (852 kilometers) from Cairo. The graveyard was used between 1750 B.C. and 1550 B.C. by nomadic people who traveled north into the region from Nubia, Secretary General of Egypt's Supreme Council of Antiquities Mostafa Waziri said in the statement.

Other recent discoveries at Kom Ombo include a statue of a cobra-crowned sphinx, engravings of a warrior pharaoh and a stone head representing the Roman emperor Marcus Aurelius.

In the recently excavated gravesite, the woman's body was curled inward and wrapped in a leather shroud. Scientists estimated that she was around 25 years old when she died. Archaeologists inspected her pelvic bones and discovered abnormalities that may have stemmed from an old fracture that was improperly set or that had healed incorrectly. This may have contributed to the woman's difficulties during childbirth, ultimately leading to her death and that of her fetus, Waziri said.

Objects found in the grave included a pottery jar, a container that was colored red on the outside and black on the inside in the style of pots made in ancient Nubia, and beads made from the shell of an ostrich egg. Some unworked shell material was included near the body, possibly indicating that the woman was a bead maker, according to the statement.

All of these funerary objects were likely included to honor the dead woman and to show the respect of her family and loved ones, ministry representatives said.

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Originally publishedon Live Science.

A big place

The Desierto de Chihuahua is the largest desert in North America as it covers over 200,000 square miles (517,998 square kilometers) and extends deep into the Central Plateau of Mexico. Its many endemic plant species suggest that the desert just might be the most biologically diverse desert in the world. The norther portion of the Chihuahuan Desert projects north of the international border into southcentral New Mexico, creating a rare and vast area of white gypsum sand dunes.

Limited access

From space, this is the largest gypsum dune field in the world and its accompanying seasonal lake, Lake Lucero, can be seen within an internally drained valley known as the Tularosa Basin. The dune field covers some 275 square miles (712 square km) at an elevation ranging from 3,890 to 4,116 feet (1,186 to 1,255 m). Some 40 percent of the dune field is protected within the White Sands National Monument. The remaining 60 percent of the dunes are within a United States military area and that limits its use by the public.

From here to there

Surrounding the dunes are the San Andres and Sacramento Mountains, the source of the gypsum powdered sand. For many millennia, rains have eroded these mountains, washing the grains of gypsum into the valley and depositing them into Lake Lucero. In the extreme desert heat, the evaporating water of the seasonal lake leaves behind fine gypsum sand, resulting in the prevailing westerly winds blowing the gypsum particles into massive white sand dunes.

Misplaced Beauty

Even though gypsum is one of the most common minerals found on Earth, seldom is it seen or found on the Earth's surface. That's because gypsum dissolves easily in water. The genesis of this white sand desert began some 100 million years ago when this area of what is now North America was covered by a shallow sea. When the sea receded and the saltwater lakes evaporated, thick layers of salt and gypsum were left covering the ancient seabed landscape.

Years in the making

Some 70 million years ago, during a period of regional mountain building, the nearby San Andres Mountains and Sacramento Mountains were uplifted to elevations as high as 9,695 feet (2,955 m). As the mountains rose high above the newly formed Tularosa Basin, so too did the thick deposits of gypsum. Thousands of years of rain and snow dissolved the high mountain gypsum, washing it down the many mountain slopes into the basin where it accumulated in Lake Lucero. When the lake water evaporates, a thin layer of crystallized gypsum, called selenite, was left behind. The continuation of weathering breaks the selenite into crystals of fine grains of gypsum sand, which the winds pile high into steep dunes. Some of the more spectacular dunes can reach a height of 60 feet (18 m).

Unique in the World

Geologists define sand as any substance composed of a mineral between 0.003 and 0.08 inches (0.065 to 2 mm) in diameter. Most of the sand found on Earth is composed of quartz. Most of this quartz sand began as a rock such as sandstone, limestone or granite and over time weathered into the small grains of quartz sand. The white sand dunes of New Mexico are about 98 percent pure gypsum sand and because of the regional aridness of the land, resulted in the massive windblown white sand dunes. Geologists estimate that 4.5 billion tons (4.08 metric tons) of white gypsum make up the 275 square miles of white sand dunes found here.

Living in extremes

The regions between the dunes are fascinating environments where determined wildlife scrape by a living in the inhospitable environment. The soil found within the dune field ranges from shallow to very deep. Some areas of the inter-dune fields are poorly drained, while other areas drain excessively. The groundwater system found within the basin is complex and scientists still don't complete understand of the system.

Flora of the desert

More than 300 species of plants can be found growing in the white sand dune field. They play a critical role in the region's ecology, stabilizing the edges of the dunes and providing both shelter and food for local wildlife. The plants that survive in this nutrient-poor alkaline soil must be able to adapt and endure high soil salt levels, drought and freezing temperatures — minus 100 degrees Fahrenheit (38 degrees Celsius). On the active sand dunes, the dominant species of plants include the soaptree yucca (Yucca elata), shown here, as well as skunkbush sumac (Rhus trilobata), fourwing saltbush (Atriplex canescens) and gyp grama (Bouteloua breviseta).

Home to many

More than 250 species of birds, numerous species of insects, 50 species of mammals, seven species of amphibians, one species of fish and 30 species of reptiles, including this diamondback rattlesnake (Crotalus atrox), make their homes within this unique white sand dune field.

Adapting to the environment

Some animals found within the dune field have adapted and evolved to their harsh white arid environment. The Apache pocket mouse, Perognathus flavescens apachii, with its almost white fur, is harder for predators to see among the white sand dunes. Since more of the white-furred pocket mice survive, relative to mice with non-white fur, they pass the genes for white fur on to the future generations of pocket mice. This adaptation to the white sands can also be seen in other species of insects and lizards that make their homes here.

Rare finds

The uniqueness and raw beauty of the white sand dunes have long been recognized. The idea of preserving the area from development started as early as 1898, when a group of El Paso, Texas community leaders proposed the formation of Mescalero National Park. That idea failed, but in 1933, President Herbert Hoover sought to preserve the area under the Antiquities Act of 1906 with a national monument designation. Today, over 500,000 people come to the white sands to explore and experience this unique natural wonder every year.

Ancient passage

Ancient footprints of such animals as mammoths and mastodons, sabertooth cats and the huge 8,000-pound (3,629 kg) ground sloth have been found around and under the dunes; so too have the footprints of early man. National Park Service paleontologists state that "thousands and thousands of trackways" are found across the region. These megatrack sites are the largest ones known in North America from the Pleistocene epoch, which ended some 12,000 years ago.

A grand landscape

There is no place like it on the planet — this land of massive gypsum sand dunes. It is one of the world's great natural wonders, and it is so easy to visit being only a short 16-mile (26 km) drive from Alamogorda, New Mexico. Some have described it as a lunar landscape, or an ocean of sand or simply a land of splendid desolation. But for those who come and experience these massive white sands dunes, they almost always depart this landscape with a feeling of peacefulness and awe.

A nighttime view

The Great North American Deserts of the southwestern United States and northern Mexico are vast arid regions where a highly diverse population of plants, animals and even humans have adapted to the region's lack of annual rainfall. But occasionally within these arid lands, the groundwater table meets or even breaks through the surface and creates unique islands where life not only survives but thrives.

Shown here is a nighttime view of one such place known as Cottonwood Springs Oasis, which is located in California in Joshua Tree National Monument.

Natural pools

Even in the continent's hottest and driest place — Death Valley National Park of the Mohave Desert — natural pools of water can be found in the remote section of the park known as Salina Valley Warm Springs. Once this area was dominated by salt and borax miners; but today, this hard-to-reach place is the quintessential oasis in the desert, with tall palm trees and human-made soaking tubs like the one shown here.

Botanists tell us that across the North American deserts, there are only 158 desert fan palm oases — with Cottonwood and Salina Valley Springs being two of them.

Remote watering hole

One of North America's most unique desert oases is called Quitobaquito Springs. Quitobaquito, (key-toe-bah-key-toe) was described by a National Parks' researcher as an "ecological singularity, as everything there stands in sharp contrast to its surrounding."

Here, in one of the most remote and driest areas of the Sonoran Desert, a lush oasis of trees and grasses surround a small pond and provide life-giving water for a vast variety of desert wildlife.

Water source

Today, Quitobaquito Springs is near the southwest corner of the Organ Pipe Cactus National Monument, a 333,688-acre (133,825 hectares) biosphere reserve that shares the international border with the Mexican state of Sonora. In fact, Quitobaquito Springs is only 200 yards (182 meters) north of the international border. The spring flows to form a small, shallow pond, which is the last freestanding water source in this part of the Sonoran Desert until the Colorado River, some 120 miles (370 kilometers) to the west. It is believed to be the longest stretch of waterless land in North America's deserts. Even in Death Valley, a drinkable source of water is never more than 20 miles (32 km) away.

Fresh water

The meaning of the name Quitobaquito is lost to history. Onomatologists, individuals who study names, believe Quitobaquito is a corruption of the Spanish and local native O'odham languages with meanings ranging from "little spring" to "house-ring spring."

What is a known fact is that Native American people have used Quitobaquito as a source of freshwater since at least 11,000 B.C. Quitobaquito also was a critical watering stop along El Camino del Diablo, the "highway of the devil,” for such early Spanish explorers as Father Eusebio Francisco Kino, Melchor Díaz, Father Francisco Tomás Garcés and Juan Bautista de Anza during the 17th, 18th and 19th centuries.

An original source

The source of fresh water for the Quitobaquito Springs is the Rio Sonoyta aquifer, which is jointly shared by Mexico and the United States. The water originates from a fault in the granite-gneiss cliffs of the nearby Quitobaquito Hills and the Agua Dulce Mountains.

Surprisingly, there appears to be little or no correlation between the monthly average discharge of water from Quitobaquito Springs and total monthly rainfall, a 1996 report from the U.S. Geological Survey found. This would indicate that there is, and has been for centuries, a sufficient flow of groundwater. Hydrologists contend that the water from Quitobaquito Springs is less than 2,000 years old and likely comes from local sources.

Old canals

This geological fault allows for the deep, underground water to be pushed up through a series of natural granite cracks. Once at the surface, the water originally ran along naturally sloping ditches that formed small standing pools of fresh water.

Beginning in the mid-1860s, a settler at Quitobaquito Springs named Andrew Dorsey changed this system by building an earthen dam and creating a small pond. He then built a series of irrigation canals to carry this water to his fields of pomegranate and fig trees. A modern day, cement-lined flow canal from Quitobaquito Springs is shown here.

Rare species

Over 270 species of plants, over a hundred species of birds and uncountable numbers of insect species count on Quitobaquito Springs as the only source of life-giving water in this vast sea of endless deserts. The pond's most famous residents are the Quitobaquito pupfish, Cyprinodon macularius ememus, shown here.

This up to 2-inch-long (5 centimeters) fish is locally known as the Sonoyta pupfish and is one of the most distinct species of its genus. The adults are aggressive omnivores eating mosquito larvae, small invertebrates and even their own eggs and young. They have a unique ability to live in water that is very hot (upward to 113 degrees Fahrenheit, or 45 degrees Celsius), very concentrated with salt (twice that of seawater) and low in dissolved oxygen concentrations. Quitobaquito pupfish only live in the pond at Quitobaquito Springs and are considered an endangered species.

Native animals and plants

Amazingly, the small Quitobaquito Springs is also the native home to several other species of unique and endangered animals and plants. The Sonoyta mud turtle, Kinosternon sonoriense longifemorale, whose is young shown here, is now only found naturally in the United States in this rare desert oasis environment. These small reptiles, with their webbed feet and innate ability to swim, have evolved in one of the driest places in North America.

Quitobaquito Springs is also the only natural habitat in the United States for the black-pepper-grain-size Quitobaquito snail, Tryonia quitobaquitae and the desert caper plant, Atamisquea emarginata.

Making it home

explains why this area has the highest number of bird species found in the Sonoran Desert. Some 73 species of birds requiring open water and/or marshland have been documented. Some 21 species of ducks and geese, four species of grebe (a freshwater diving bird), seven species of heron and egret, 19 species of "shorebirds" and nine species of gulls spend time in and around the pond at Quitobaquito Springs.

Shown here, a flock of American avocets, Recurvirostra americana, fly over Quitobaquito Pond.

Local trading system

The prehistoric trade route — known as the Old Salt Trail — passes by the Quitobaquito Springs. Native American people used this route for centuries as they passed by the oasis in search of obsidian, seashells and salt from the large salt beds found in Sonora, Mexico. Both the Hia C-ed O'odham and the Tohono O'odham people of today claim the oasis as a part of their historic homeland. The before mentioned Andrew Dorsey even opened a store near the springs and created a system of trading coins, like the one shown here, for the local people to use.

In 1957, Jim Orosco, a member of the Hia C-ed O'odham tribe, sold all of his remaining private land at Quitobaquito to the National Park Service for $13,000, ending his family's ownership of that land, which had begun in 1887.

A place of abundance

Our natural world is full of remarkable places, exceptional not only for their beauty but their very existence. Quitobaquito Springs could certainly be added to that special place list. Here, in some of the most arid lands found anywhere in North America, this flowing spring and resulting pond have allowed both humans and non-arid plants and animals to live and thrive for thousands of years.

For now, the ecosystem of Quitobaquito Springs is stable and under the protection of the National Parks Service, but such a unique place will require constant monitoring to assure its survival into the future.

The Sahara — the world’s biggest hot desert — is getting even bigger. In fact, it is currently about 10 percent larger than it was nearly a century ago, and scientists suggest that climate change is partly responsible.

In a new study, researchers examined rainfall data gathered across Africa, consulting records dating back to 1920 and noting how changing conditions affected regions around the boundaries of the great desert.

They discovered that while some natural climate cycles could partly explain reduced rainfall and desert expansion southward, human-driven climate change is also playing a part. And if climate change continues unchecked, the Sahara's slow growth will likely continue, the study authors reported. [The Sahara: Facts, Climate and Animals of the Desert]

Previously, scientists had explored the Sahara's expansion by examining satellite data dating back to the 1980s. This study, which was supported by the U.S. National Science Foundation, is the first to analyze long-term trends in rainfall and surface air temperature over a timescale of nearly an entire century, the study's lead author, Natalie Thomas, a doctoral candidate in atmospheric and oceanic science at the University of Maryland, told Live Science.

Deserts are defined as places on Earth that receive less than 10 inches (25 centimeters) of rainfall per year, according to the U.S. Geological Survey (USGS). With a surface area of about 3.6 million square miles (9.4 million square kilometers), the Sahara is the third-largest desert in the world. Only the cold deserts are bigger: icy Antarctica's frozen desert spans about 5.5 million square miles (14.2 million square km), and the Arctic desert covers around 5.4 million square miles (13.98 million square km), USGS reported.

"A strong expansion"

The study authors originally set out to examine seasonal cycles of temperature and rainfall across Africa, consulting data spanning 1920 to 2013. But their attention was quickly drawn to trends of decreasing precipitation in the Sahel, a semiarid region linking the Sahara to the savannas of Sudan. By looking at this more closely, they hoped to discover how rainfall trends might be linked to the Sahara's growth over time, according to Thomas.

To a certain extent, many deserts' boundaries expand and contract seasonally, as conditions fluctuate between wetter or drier. But the researchers found that there has been "a strong expansion" of the Sahara within the 20th century, Thomas said.

Depending on the season, the Sahara experienced growth of at least 11 percent, and it grew by as much as 18 percent during the driest summer months, according to data collected over roughly 100 years. Over the course of a century, it steadily expanded to become about 10 percent bigger than it was in 1920, the study authors reported.

Much of the Sahara's overall size increase can be explained by climate cycles driven by anomalies in sea-surface temperatures. These cyclical changes in turn affect surface temperatures and precipitation on land, and their impact can last for decades, according to the study.

Decades of drought

One such cycle, the Atlantic Multidecadal Oscillation (AMO), entered what is known as a "negative phase" — with cooler-than-average sea-surface temperatures — in the 1950s, bringing heat and dry conditions to the Sahel region and fueling a drought that lasted until the 1980s, Thomas said.

Using statistical methods, the scientists compensated for the effects of the AMO on average rainfall, and thereby calculated how much of the Sahara's growth could be explained by the dryness that the cycle's negative phase produces. They estimated that the AMO accounted for about two-thirds of the desert's expansion — but one-third of the Sahara's remaining growth was likely the result of climate change.

The researchers' findings point to changes that occur over decades rather than in a single year, and that makes it hard to predict exactly how the Sahara's continued growth could affect the wildlife and people near its changing borders. But as the places where humans grow food become increasingly drier, some areas could become more vulnerable to drought, bringing a greater risk of famine to the people who live there, Thomas said.

The findings were published online today (March 29) in the Journal of Climate.

Original article on Live Science.

Beachgoing sandcastle builders know the exquisite frustration of tunneling into sand that's too dry. The tunnel simply won't hold its shape and quickly collapses.

But some types of desert spiders have mastered the technique of working with dry sand, excavating subterranean burrows — a few grains of sand at a time — that somehow retain their form and withstand pressures from wind and the shifting weight of the sand around them.

In a new study, scientists closely observed four species of desert spiders known to excavate vertical sand tunnels for hiding, resting and breeding, in order to dig up their engineering secrets. Unexpectedly, the researchers discovered that the arachnids used different yet equally effective methods for collecting and moving sand while they worked, and they strengthened the tunnels as they dug with carefully laid supporting layers of silk webbing. [Photos: Modeling Scorpions' Lairs in 3D]

Burrow-dwelling spiders like those in the study are strictly nocturnal. For the scientists, that meant spending long hours crouched in sandy environments with a flashlight, the study's lead author Rainer Foelix, an arachnologist at the Neue Kantonsschule Aarau in Switzerland, told Live Science in an email. 

One of the spider species — Cebrennus rechenbergi, which is native to the deserts of northern Morocco — is also known as the cartwheeling spider for the unusual rolling locomotion that it uses when threatened. It has a body length of about 0.8 inches (2 centimeters), and digs burrows measuring about 10 inches (25 cm) deep and around 0.8 inches in diameter. When study co-author Ingo Rechenberg, a professor at the Technische Universität Berlin (Technical University of Berlin) and the scientist who discovered and named the spider, observed how these spiders worked, he noted that they built their tunnels "like people build a well," Foelix told Live Science.

First, the C. rechenbergi spider excavated a hole on the surface; then it added a stabilizing ring of silk, in the same way a human well builder would add a tin sheet to hold the walls of the hole in place. Once the walls of a tunnel section were secured, the spider would remove another layer of sand and soil, moving farther down and reinforcing the walls as it went, the study authors reported.

"Rechenberg watched carefully and noticed that a spider has to make about 800 runs to carry a small load of sand aboveground" — a task that took the spider about 2 hours to finish, Foelix said.

But how did the spiders remove so much sand? It turned out that different species of burrow-digging spiders used very different methods, according to the study.

C. rechenbergi relied on long bristles fringing its pedipalps and chelicerae — appendages that frame its head and mouth — to carry sand out of its growing tunnel. Some of the bristles grow at right angles to other tiny hairs, forming a type of mesh basket that contains arid sand even when there's nothing else holding grains together. In fact, the tiny piles of sand that the spider discarded from these "baskets" disintegrated immediately once the arachnid released them, the scientists wrote in the study.

However, the wolf spider Evippomma rechenbergi — also discovered and named by Rechenberg — which inhabits the same desert environment as C. rechenbergi, lacks the specialized bristles of its neighbor. When the scientists carefully inspected clumps of sand left at the mouth of the wolf spider's burrow, they detected strands of silk binding the sand together, to make it easier to carry.

Another type of wolf spider, Geolycosa missouriensis, found in North America, was known from prior research to transport solid pellets of sand. But it did not appear to bind them with silk, perhaps relying on surface moisture to hold the sand grains together. However, as the researchers gathered their data about this spider from previous studies, they could not say for sure what technique the spiders used to consolidate their sand bundles.

The variety of sand-moving methods demonstrated by the spiders — using a hairy "carrying basket," blending sand with silk or clumping sand grains together — showed that these tiny builders are capable of finding unique construction solutions to address similar environmental challenges, Foelix told Live Science.

In fact, the researchers were surprised to see that spiders living in the same ecosystem practiced such diverse techniques for achieving the same goal, he said. And considering there are other types of tunnel-digging spiders — as well as ants and wasps — there are likely even more practices that these industrious insect engineers are putting to work, which are yet to be discovered, Foelix said.

"Certainly, many more species need to be inspected," he added.

The findings were published online Dec. 11 in the Journal of Arachnology.

Original article on Live Science.

Four legs good, two legs bad? Not if you're a jerboa, a tiny, bipedal, desert rodent. These miniscule mammals get around using only their two hind legs to hop, skip and jump across their arid habitats.

And the creatures mix and match those locomotion styles to produce hard-to-follow moves that help them evade the jaws of hungry predators, according to a new study.

In fact, researchers found that jerboas' fancy footwork was much more unpredictable than the movements of other small desert rodents that scurry on four legs to avoid trouble. This likely lends jerboas a distinct advantage when a hunter is in hot pursuit, the researchers in the new study said. [The World's 6 Smallest Mammals]

Jerboas live in deserts in northern Africa and in Asia, and they belong to a family of bipedal rodents called Dipodidae. While all the rodents in this family jump, jerboas have exceptionally long, spindly hind limbs that can be three times as long as their forelimbs. To put those proportions into perspective, imagine a person who is 6 feet (2 meters) tall, but whose arms are only 11 inches (27 centimeters) long.

Jerboas not only have dramatically elongated legs; they also use these limbs in a more versatile manner than do other bipedal rodents, such as kangaroo rats and jumping mice. Unlike their bipedal cousins, who merely jump, jerboas employ several gaits: running, jumping with both legs or hopping from one leg to another. And researchers discovered that jerboas habitually transition between these gaits midstride, tossing in bursts of speed and hairpin direction changes to produce dizzyingly evasive maneuvers.

Hoppily ever after

Scientists often study how animals move by placing them on treadmills, but the study authors wanted to observe how jerboas might move in the wild. And to do that, they needed to give the jerboas room to jump around in all directions, study lead author Talia Moore, a postdoctoral fellow with the department of Ecology and Evolutionary Biology at the University of Michigan, told Live Science in an email.

"I knew that I had restricted the motion of the animals in the lab by putting them on a narrow racetrack, so I wanted to give them an open area to see what they would do," Moore explained.

Moore and her colleagues built an outdoor mesh enclosure at a desert location in China where they had previously seen jerboas; that way, the animals would freely encounter and respond to stimuli they would typically come across in their natural habitat, the researchers said. Because jerboas are active at night, the researchers illuminated the enclosure with infrared lights, which the animals couldn't see, and used multiple cameras to record the creatures' actions, Moore said.

"Lo and behold, they jumped around like crazy! It's a good thing we had them in the enclosure — otherwise, we would never have been able to recapture them!" she said.

After the cameras recorded the jerboas, the researchers devised a method to measure the unpredictability of the animals' movements, then compared those moves to the scampering of quadrupedal rodents. The scientists' calculations — measuring and analyzing movement over the ground in 3D space — showed that the jerboas' hodgepodge motion was, in fact, more unpredictable than the movements of rodents that used four legs.

"This increased unpredictability likely arises from their unique gait use and gives them an edge in the evolutionary arms race between predator and prey," Moore said in a statement.

Predators like snakes and birds, which are common in the jerboas' desert ecosystems, typically track their prey's movements, Moore said. To catch the animals, the predators line up a strike by predicting where the prey is going and intercepting its path, which means that an animal that is harder to track will be harder to catch, Moore said.

"This form of predation fails spectacularly when the prey locomotion is unpredictable, like [that of] the jerboas," she said.

The findings were published online Sept. 5 in the journal Nature Communications.

Original article on Live Science.

An unexpected rain has caused the world's driest nonpolar desert to burst into bloom.

Chile's Atacama Desert typically gets a mere 0.6 inches (15 millimeters) of rain every year. But unusual rains that fell during the winter in northern Chile led the barren landscape to blossom in August.

Typically, the Atacama becomes an endless field of wildflowers once every five to seven years due to rains from El Niño, a climate cycle in the Pacific Ocean. This rare transformation is known as a "super bloom" and has earned the desert the nickname "desierto florido" ("flowering desert" in Spanish) from locals. [Photos: Colorful Blooms Sprout Across the World's Driest Desert]

The desert holds millions of dormant seeds in its soils. When rain waters these seeds, they can open and take root, eventually growing into flowers that are red, orange, yellow, purple and white.

The last super bloom happened in 2015, and the next one wasn't expected for several more years. But the unexpected rains delivered a rare treat: fragrant flowers ahead of schedule.

The Atacama Desert sits on a 600-mile-long (1,000 kilometers) plateau in northern Chile that borders Peru, Bolivia and Argentina. The harsh, arid land is sparsely populated, but thousands of tourists flock there during super blooms to see the more than 200 floral and wildlife species, Live Science previously reported.

Original article on Live Science.

Introduction

Chile's Atacama Desert, one of the world's driest places, is now flush with flowers after an unexpected rain.

The desert typically gets just 0.6 inches (15 millimeters) of rain a year. Even so, it's earned the name "desierto florido" (flowering desert) from locals because whenever it rains enough, dormant seeds in the soil take root, and burst into a wide array of yellow, orange, green, purple and red.

These "super blooms" typically happen every five to seven years because of El Niño, a climatic cycle in the Pacific Ocean. But the last super blooms sprung up in 2015, making this one a colorful and fragrant surprise.

Yellow posies

The once arid and barren landscape of the desert is now filled with flowers after an intense and surprising rainfall in northern Chile during the winter months. This photo was taken Aug. 17.

Purple fields

These colorful blooms usually attracts thousands of tourists, who travel to see and photograph the more than 200 floral species and native wildlife. This photo was taken Aug. 22.

Mountain backdrop

Yellow and black flowers fill the landscape like a lush, floral carpet.

Research suggests that before the Atacama became an arid desert, it was filled with marshes and lakes.

Popcorn-like flowers

Beautiful white flowers have turned this valley into a speckled white landscape.

Hearty plants

Heavy rains helped millions of seeds take root in the Atacama Desert, the highest and driest nonpolar desert on Earth.

Signs of spring

By mid-February in the three great hot and dry deserts of the American West, wildflowers turn stark desert landscapes into a sea of color. Whether it is in the low plains of Death Valley or among the saguaro forests of the Sonoran Desert, wildflowers become for a short time the most common of plants, while also signaling the arrival of another spring.

Colorful deserts

Every color of the rainbow can be found across the land which, in another short three months, will return to the drab shades of browns and blacks. But for now, the gold of the California poppy (Eschscholzia californica), or the blue of lupine (Lupinus preens) and the purple of the owl's clover (Castilleja exserta), as shown here, all turn the desert into a magic carpet of natural beauty.

Western Swallowtail

And as surely as the explosion of wildflowers occurs across the desert lands each spring, so too do the many species of butterflies returning to feed upon them. In the Sonoran Desert alone, there are more than 250 species of butterflies found flittering across the desert floor, from one wildflower to another. Here, a Western Swallowtail (Papilio rutulus) enjoys a quick meal of nectar.

American Snout

The American snout (Libytheana carinenta) is a common butterfly of these American deserts. It has an extremely wide distribution from central California to the eastern United States, south through Central America and South America to Argentina. Each spring in the West, there is a mass migration northward of millions of these butterflies. Two generations of butterflies occur each year. The adult wingspan measure 1.6 inches to 1.9 inches (4 to 5 centimeters) and they seem to have a preference for feeding on yellow and white flowers.

Painted Lady butterfly larvae

The return of butterflies to these deserts is soon followed by an explosion of their young caterpillars feeding on the annual crop of desert wildflowers. Shown here is the larvae of the Painted Lady butterfly (Vanessa cardui) as it feeds of the Common Fiddleneck (Amsinckia menziesti) flower in the Sonoran Desert of Arizona.

Painted Lady

The Painted Lady is also known in some parts as the Thistle Butterfly because of its caterpillars' apparent fondness for thistle plants. It is the most widely dispersed butterfly in the world, as it can be found on every continent except Australia and Antarctica. Occasionally a population explosion of the Painted Lady butterfly in the deserts of northern Mexico results in a migration of the butterfly into the far north of Canada.

Gold-hunter's Hairstreak

The Gold-hunter's Hairstreak (Satyrium auretorum) is a common visitor to these southwest deserts. Desert milkweed (Asciepias subulata) is a favorite food of this butterfly, which has a wingspan of 1 inch to 1 1/4 inches (2.5 to 3.2 cm). Hairstreak butterflies belong to the Lycaenidae Family and are part of the true butterfly Superfamily Papilionoidea. There are approximately 4,700 species of this family of butterfly found around the world.

Great Purple Hairstreak

The colorful Great Purple Hairstreak (Atlides halesus) is another member of the Superfamily Papilionoidea found in the deserts of the American West. The Great Purple Hairstreak has one short and one long tail protruding from its hind wing. Adults have a wingspan of 1 1/4 inches to 2 inches (3.2 to 5.1 cm). Mistletoe often found growing on mesquite and palo verde trees of the desert regions are a favorite food of the Hairstreak's caterpillars.

Queen butterfly

The Queen butterfly (Danaus gilippus) is a year-round resident in the deserts of the American West. It is a relative of the Common Monarch (Danaus plexippus), but is darker in color. Adult Queen butterflies have a wingspan of 2 5/8 inches to 3 7/8 inches (6.7 to 9.8 cm). The larvae of the Queen feed on the various species of milkweed that grow throughout the desert. Queen butterflies are found throughout the American deserts and in the southern regions of the United States, south through Mexico, Central and South America to Argentina.

Checkered White

The Checkered White (Pontia protodice) is a commonly found butterfly in the middle and lower elevations of the American deserts. They are most common from March to May but can be found in the warm regions of the desert all year round. A smaller desert butterfly with a wingspan of only 1 1/2 inches to 2 1/2 inches (3.8 to 6.3 cm), Larvae of the Checkered Whites prefer to feed on the flowers, buds and fruits of their host, but will consume leaves when only leaves are available. They dine on the variety of plants from the mustard, cabbage and caper families that grow across the desert regions.

Western Pygmy-Blue

The Western Pygmy-Blue (Brephidium exilis), one of the smallest butterflies in the world, has a wingspan of only 1/2 inch to 3/4 inch (1.2 to 2 cm), and is a common resident of the American deserts. Caterpillars feed on the many species of saltbush found across these desert regions. They are part of the gossamer wing family of butterflies, or those whose wings appear delicate and shimmery because they are covered by both pigmented and light-reflecting scales. These miniature butterflies are found from central California east to Texas and south throughout Baja California, Mexico to Venezuela. Interestingly, the tiny chrysalises of the Western Pygmy-Blue can make a faint noise that lepidopterists think might help scare off hungry ants.

New life begins

And so, as winter still holds a chilling grip on much of North America, spring has now arrived in the southwestern American deserts. The annual carpet of beautiful wildflowers and their many butterfly companions are once again signaling that a new year of life and growth has begun.

yellow-flowers-blue-sky

Yellow flowers paint a bright contrast against the bright blue sky in Anza Borrego State Park in 2017. The area experienced a superbloom thanks to a wet winter.

yellow-flowers

More yellow flowers from Anza Borrego State Park's 2017 superbloom.

yellow-purple-orange-flowers

Fields of yellow, purple and orange flowers carpet the desert in Anza Borrego State Park in March 2017. The area is experiencing an explosion of color thanks to a wet 2017 winter.

yellow-flowers-shiny

Yellow flowers show a burst of color against the rocky landscape of Anza Borrego State Park in March 2017. The area is undergoing a superbloom, thanks to a wet 2017 winter season.

yellow-flowers-valley

A field of yellow flowers paint the valley floor in the harsh desert landscape of Anza Borrego State Park in March 2017. The area has had a burst of flowers thanks to a superbloom from a wet winter.

yellow-flowers-sunset

A yellow flower pops out of the desert in the fading sun in Anza Borrego State Park in March 2017. The area is undergoing a superbloom thanks to the wet winter.

purple-flowers-anza-borrego

Purple flowers fill the background as a lone yellow flower makes itself known in a superbloom taking place in Anza Borrego State Park this March, 2017.

flowers-anza-borrego

Fields of flowers are bursting from the barren desert in Anza Borrego STate Park in Southern California this year, thanks to a wet winter.

anza-borrego-desert

During the dry season, Anza Borrego State Park in Southern California presents a forbidding landscape.

anza-borrego-state-park

A fiery sunset with a rainbow in Anza Borrego State Park

Spirited fowl

Across the desert regions of the southwestern United States southward into central Mexico, a feisty little bird thrives. The sight and scolding sounds of the cactus wren, Campylorhynchus brunneicapillus, is a daily occurrence for all who live among them in these large desert regions of North America.

Life span

The cactus wren is the largest wren in North America, growing to be 7-9 inches (17-23 centimeters) long and weighing from 1-3 ounces (28-85 grams). Banded cactus wrens have been shown to live upwards of 6 years.

Pretty face

Cactus wrens have a distinctive white eye stripe above and behind each eye. Its breast is heavily spotted with shades of brown, black and sometimes a hint of orange. Its wings and long tail are barred with white, black and brown feathers. The bird's beak is slightly curved.

Desert dwellers

Cactus wrens are desert dwellers and live in and among the forests of cacti found across this region. The sharp spines of the many species of cholla cacti are among its favorite, because the woody interior of the cholla cacti is strong enough to support the bird and its large nests.

A place to call home

Forests of cholla, such as these anything-but-soft Teddy Bear cholla (Cylindropuntia bigelovii), are common across the desert regions of California, Nevada, Arizona, New Mexico, western Texas and the desert regions of western and central Mexico. Where you find a cholla forest you are sure to find the cactus wren.

Nesting

The female cactus wren will select the nesting site among the cholla or within thick desert scrub and trees. The birds will even nest in an abandoned woodpecker "boot" found within a giant saguaro cactus (Carnegiea gigantea). Males help build the large football-shaped nest from local grasses with the interior lined with soft feathers. The side entrance helps protect the young from local predators.

Family time

Cactus wrens mate in late February through March. They may produce up to three broods every season. Three to six eggs are laid and hatch in about two weeks. The young leave the nest within three weeks of hatching. Cactus wrens often build two nests: one for their young and one for their own roosting. Here, a cactus wren's nest is built among a chained-fruit cholla (Cylindropuntia fulgida).

Hearty animals

Cactus wrens are true desert dwellers. They survive well for long periods of time without ever drinking free-standing water because they get their moisture from the fruits, seeds and insects that they feast on. Here, a cactus wren eats the ripened red fruit of a saguaro.

Snack time

Cactus wrens are mainly ground foragers. Their quick, wren-like movements make them excellent hunters of even small reptiles. They overturn leaves and rocks looking for any small creature hiding underneath. The birds tend to feed during the early morning hours, avoiding the extreme high temperatures of hot summer afternoons. They are often found searching for food in the shady areas found under the desert shrubs and trees.

Unique voice

The loud and raspy call of the cactus wren is a common sound throughout these desert regions. The notes resemble somewhat of a "char-char-char" sound. Cactus wrens are noisy birds, and they will challenge any other bird, animal or human who happens to come within their territory. Males and females form pair bonds and will defend their territory through the year.

Good neighbors

Cactus wrens live well among humans. They are common residents in the cities of these desert regions. The birds scold and call out humans as well as the family dog or cat anytime one gets too close to a nest or near the young. Here, a cactus wren finds a tasty meal of saguaro seeds along with a friendly white-winged dove (Zenaida asiatica).

Curious creatures

Cactus wrens are nosy creatures. They will freely fly into an open garage or open car window just to see what morsel of food might be found there. They always seem to be in a hurry, as well as a little agitated. Their behaviors can be somewhat humorous as they rush around tending to their daily tasks. The state of Arizona made the lovable cactus wren its official state bird in 1931.

A burn scar left by a wildfire in Western Australia is so massive, it's visible from space, according to images captured by a NASA satellite.

But fires that leave immense scars in their wake — such as this one in the Gibson Desert, just 50 miles (80 kilometers) southwest of Lake Mackay — aren't entirely unexpected, NASA said. That's because the native Aboriginal people who once routinely set fire to their land no longer live there, allowing desert grasses to grow out of control and into a colossal tinderbox.

"For tens of thousands of years, nomadic Aboriginal people traveled the harsh landscape around Lake Mackay looking for food and water," NASA's Earth Observatory said in a statement. "That nomadic lifestyle was transformed when the British military began missile tests in the region in [the] 1950s; most of the Pintupi people [an Australian Aboriginal group] living in the area ended up in small settlements such as Kiwirrkurra" — located in the Gibson Desert. [Top 10 Deadliest Natural Disasters in History]

Before their relocation, the Pintupi would purposefully light wildfires for several reasons: to encourage the growth of certain edible plants that were only plentiful in the years following a fire, to drive game animals out of their burrows, and to make hunting animals easier, partly because the animals would have few places to hide, NASA said.

But after the British intervened, the landscape in the Pintupi's former stomping grounds changed. The Pintupi were no longer there to ignite fires, and so the desert vegetation grew. Now, when a blaze begins, whether it is man-made or from a lightning strike, it burns brightly and covers a large area.

A comparison of aerial imagery from the 1950s with a series of recent images captured by NASA Landsat satellites shows that fire scars left around Lake Mackay have grown much larger since the Pintupi relocated, said Neil Burrows, an ecologist with Western Australia's forest department.

The Operational Land Imager (OLI) on the Landsat 8 satellite captured the recent image of the Gibson Desert on Nov. 19, 2015. The light-orange burn scar stands out in stark contrast to the darker-orange areas that have not been burned in recent years. These unburned areas are home to the desert grass Triodia, NASA said.

This burn mark, located south of a mountain range (shown in gray in the image), was likely the product of a fire started by a lightning strike on Nov. 7, 2015, according to imagery taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors on NASA's Aqua and Terra satellites, NASA said.

Since the Aboriginal people stopped their traditional burning practice, it has been relatively common for a single fire to be several hundred thousand hectares, he said. "In 2012, to the south of this fire, a fire burnt 3.2 million hectares (7.9 million acres) over two weeks," Burrows added.

These fires are changing more than just the landscape. Ecologists have documented a sharp decline in native mammal populations in the area, and these intense fires are likely contributing to the problem, Burrows said.

Original article on Live Science.

Anthophora Pueblo

A new species of desert-dwelling bee, Anthophora pueblo, peeks out of its sandstone nest. These bees gnaw holes into the rock, a difficult process that leaves older bees with worn-out mandibles. New research published Sept. 12 in the journal Current Biology, however, suggests that these bees get benefits from building their homes to last.

[Read full story on the sandstone bees]

A Bee Pueblo

Anthophora pueblo nests at Grand Staircase-Escalante National Monument in Utah. Bees reuse the tunnels for generations, meaning that the hard work of excavation may pay off for a bee's offspring.

Bunches of bees

A sandstone wall is crammed with Anthophora pueblo bee nests at Johnson Lakes Canyon in Utah. Researchers reported seven sites in Utah, Colorado and California where these bees nest in a Sept. 12 paper in the journal Current biology. Since then, study author Michael Orr of Utah State University says he's found more than 50 additional nesting sites. The bees require habitat with just the right hardness of sandstone — not too hard — Orr told Live Science, and they need a water source nearby.

[Read full story on the sandstone bees]

Hunting for bees

Michael Orr, a doctoral student at Utah State University, climbs a rock wall in southern Utah to hunt for sandstone-dwelling bees. Orr and his colleagues have found that digging into rock walls seems to benefit bees because their nests are durable. When times are lean, the bees delay their emergence and can remain holed up in a quiescent state for at least four years. Nesting in rock walls helps ensure that the bees are protected from erosion or flash flood during these periods.

A Home for Bees

A large bee nesting site near Wild Horse Creek in south-central Utah. Researchers found fewer microbes in vertical sandstone rock than sandstone on the ground. They also found that parasitic beetles that prey on bees aren't able to develop as effectively inside sandstone nests. The sandstone dwellings may thus protect bees from parasites both large and small.

Wild Horse Creek

And the views aren't bad, either! A large sandstone formation provides a home for Anthophora pueblo bees near Wild Horse Creek in south-central Utah. The bee tunnels become shelter for other insects, too, including several species of parasites, other bee species, wasps and spiders.

[Read full story on the sandstone bees]

Studying sandstone

Michael Orr of Utah State University with a chunk of sandstone removed from the San Rafael desert of Utah in the early 1980s. U.S. Department of Agriculture entomologist Frank Parker was the first to notice bees building nests in sandstone. He chiseled out rock samples and reared the bees in the lab, but never formally identified the species or published his research.

Anthophora pueblo specimen

Utah State University doctoral student Michael Orr displays a specimen of Anthophora pueblo along with its sandstone nest. Samples of this new species had been tucked away in a museum drawer for nearly 40 years before researchers formally identified the new bee.

Identifying a new species

Michael Orr of Utah State University selects a specimen of Anthophora pueblo for examination under a microscope. The desert bee seems to gain protection from the elements and from parasites by gnawing its nests out of solid rock.

[Read full story on the sandstone bees]

The twists and turns of a scorpion's underground burrows are generally inaccessible to anything that isn't a scorpion — including scientists. That is, until now.

Researchers used an unusual method to model the lairs of these underground arachnids, finding out that the subterranean refuges built by different species are surprisingly similar, even when the scorpions inhabit different environments.  

The scientists investigated the burrow construction of three species from two different genera of the Scorpionidae family, to understand how the scorpions were benefiting from their tunnels' structural designs. The scorpions lived in three locations — the Negev desert in Israel, and the Kalahari Desert and the Central Highlands, both in Namibia — where variations in soil composition and hardness could affect the types of tunnels the critters constructed. [Photos: Modeling Scorpions' Lairs in 3D]

Despite notable differences in the dirt the scorpions were digging through — silty soil in the Negev, sandy and loamy soil in the highlands, and sand dunes in the Kalahari — the scorpion species in all three locations built lairs with features that were common across all the burrow structures.

First, the scientists spent three days measuring the temperature and moisture levels at different points along the burrows. The temperatures taken inside the scorpions' tunnels matched that of the soil around it. Tunnel soil also held more water than soil at the surface, likely providing the arachnid with relief from hot, dry conditions, the researchers suggested.

Extracting a tunnel in 3D

Being unable to enter the scorpions' tunnels themselves, the researchers did the next best thing — they brought the tunnels to the surface. By pouring molten aluminum into 43 burrow openings (after first capturing the scorpions that built them) and allowing the metal to cool, they were able to extract the tunnels as 3D shapes.

They then compared the tunnel models and found that all of them had a horizontal entry platform that could be used like a front porch; a minimum of two spiral bends, likely to keep out predators and restrict surface air flow; and a chamber at the tunnel's end where the scorpion could rest and feed — and where females also perform courtship rituals, mate and deliver their young.

Burrow architecture should be recognized as complementary to the animals' biological needs, "performing functions its body would otherwise have to do on its own, like maintaining a comfortable temperature or improving ventilation," study co-author Berry Pinshow, a professor of physiological ecology at Ben-Gurion University of the Negev in Israel, said in a statement.

As biologists continue to explore still-unanswered questions about burrowing scorpions and how they live, these findings suggest that their burrowing behavior and the architecture they produce deserves closer investigation as well. The similarities between the species' burrows is especially interesting, the authors noted in the study, and hints that structural parallels may be found in the burrows of other scorpion species as well.

The findings were published online June 16 in the journal The Science of Nature.

Original article on Live Science.

Getting a closer view

Captured by an unmanned aerial vehicle (UAV, or drone), this image shows an overhead view of the large, rectangular stone platform recently detected at Petra, and the smaller rectangular structure it contained within its boundaries.

Read the full story about this unusual discovery.

Measurements and details

Detail of the massive stone platform and the smaller structure — offset to the platform's western side — with architectural details and measurements shown. The image was created as a composite using multiple photographs captured by drones.

Seen from above

Aerial image of the enormous stone platform, which measured about 184 feet by 161 feet (56 by 49 m). Petra's city center lies to the north of the structure, and an impressive “facade” — columns and stairway — were found on the side of the platform facing the east

On the ground

Christopher Tuttle, an archaeologist at Brown University and co-author of the article describing the find at Petra, is pictured standing at the southwest corner of the interior, smaller platform, looking north.

Read the full story about this unusual discovery.

Exposing the past

Detail of the west side of the small building showing the single, buried column drum in the foreground.

Flagstone floor

Archaeologists discovered exposed flagstones in the interior of the smaller platform; this view is facing north.

Ancient walkways

Archaeologist Christopher Tuttle, who co-authored the article describing the Petra platform, investigated the doorsill of the small building on the platform; this view is facing southwest.

Read the full story about this unusual discovery.

Most scientists today agree that North America has four distinct desert regions: the Great Basin, the Mojave, the Sonoran and the Chihuahuan. The subjective delineation of one from another is based primarily upon the different species of plants that can be found growing in each region. When the cacti found within these four arid lands begin to bloom in late March and April, spring has once again returned to these North American deserts.

Each desert region's pattern of precipitation, elevation and soil characteristics influence the types of floristic growth, which can blur the line as to where one desert begins and another ends. (Credit: Linda & Dr. Dick Buscher)

Related: Why Do Flowers Close Up at Night?

Cactus flowers are showy and usually quite large. They are unique flowers because they have dozens of stamens and petals, rather than the usual 5 to 10 of each that are most commonly found with flowering plants. The ovary of the cactus flower is buried deep in the flower's interior. Shown here is the bloom of the Englemann’s hedgehog (Echinocereus engelmannii). Commonly known as the Santa’s cactus and the strawberry cactus, the Englemann’s hedgehog is commonly found in the Mojave and Sonoran Deserts, at elevations between 650 and 8,000 feet (200 to 2,400 meters). Hedgehogs are one of the first of all the cactus species to bloom each spring. (Credit: NPS) 

The blooms that are light pink with red centers are the relatively rare Nichol’s hedgehog cactus (Echinocereus nicholii), which has a more limited natural range than its cousin, the Englemann's hedgehog. These spring-flowering beauties are found only in the Sonoran Desert region of southern Arizona and northern Mexico. Known commonly as the Golden hedgehog, the flowers of these long spine clusters brighten the dry washes and sunny hillsides where they are found. (Credit: NPS)

The prickly pear cactus is the only cactus species found in all four North American deserts. More than 12 distinct species of prickly pear cactus grow, bloom and thrive in the varied desert environments, and they are able to survive even the cold temperatures of the Great Basin Desert, the largest desert in the United States. Prickly pear cacti are part of the genus Opuntia. They have modified stems that resemble flat pads, which are the sites where photosynthesis and water storages occur and flowers are produced. The pads of almost all prickly pear cacti are covered with large spines that are actually the plant’s modified leaves. Just above the growth point of the regular spines is a cluster of tiny, barbed spines known as glochids.

Glochids are unique to all members of the Opuntia genus. Flowers of prickly pear cacti can be red, orange, yellow and even purple. The bloom of the Engelmann’s prickly pear (Opuntia engelmannii) is shown here. (Credit: NPS)

Other members of the Opuntia genus are the 20 species of cholla cactus that are found in the three hot North American deserts — the Mojave, Sonoran and Chihuahuan. These scrublike cacti have cylindrical stems that carry out water storage, flower production and photosynthesis, and grow in segmented joints.  Shown here, in full springtime bloom, is a common Tree cholla (Cylindropuntia imbricata). (Credit: Linda & Dr. Dick Buscher)

Unique to the cholla cactus are the papery sheaths that cover their many spines, which are actually modified leaves. Glochids are also found on all varieties of cholla cactus. Just like the prickly pear cactus, the bloom of this Staghorn cholla (Cylindropuntia versicolor) can be a variety of colors, including various shades of red, yellow and green. Staghorn cholla is also known by a second common name, the Deerhorn cholla. (Credit: Linda & Dr. Dick Buscher)

Another common species of cholla cactus found in the three hot deserts is known as the Teddy Bear Cholla (Cylindropuntia bigelovii). The segmented joints of this cholla appear from a distance to be fuzzy, like a teddy bear, and can be easily broken off. This characteristic inspired its second common name, Jumping Cholla. Teddy Bear cacti can grow to a height of 2 to 3 feet (0.3 to 0.9 m). Although the segments have no mechanism to actually jump, they do readily attach themselves to the fur of any animal, or the pant leg of a human, that brushes up against them. These are both very painful and difficult to remove. Forests of Teddy Bear Cholla cacti can cover acres of desert land, making some regions almost completely impassable. Shown here is the yellow-green springtime flower of the Teddy Bear cholla cactus. (Credit: NPS)

A small but very showy cactus found in the North American deserts is the Fishhook Pincushion cactus (Mammillaria microcarpa). These small, cylindrical cacti grow only to a height of about 6 inches (15 centimeters), and are protected by their many long, hooked spines. Even though they are small in stature, their large flowers, in shades of red, pink and orange, make for a spectacular display of color along the typically brown desert floor. (Credit: NPS)

The barrel cactus is commonly found in the three hot North American deserts. The two genera of barrel cactus, Echinocactus and Ferocactus, are made up of more than 60 different species. These squatty, tubular-shaped cacti typically grow to be 2 to 4 feet (0.3 to 1.2 m) in height, and measure 16 to 30 inches (41 to 76 cm) across. Individual cacti have been known to grow 10 feet (3 m) high. A species of the genus Ferocactus, shown here, is so named for the massive clusters of rigid spines that cover the fleshy barrel-shaped plant. The name "Ferocactus" comes from Latin and translates to mean "fierce cactus." (Credit: NPS)

Barrel cacti are spectacular bloomers, with large red, yellow, orange or purple flowers that begin to bloom each year in mid-April. The fishhook barrel cactus (Ferocactus wislizeni), shown here, is so named for the many hooked spines that cover the cactus, providing protection from hungry animals and shade from the blisteringly hot summer sun. The fishhook barrel cactus is one of the more common barrel cacti of the North American deserts. Older species often grow pointing southward, giving rise to the nickname "compass barrel." (Credit: NPS)

The Senita cactus (Lophocoreus schottii) is one of the multi-stemmed columnar cacti found in the Sonoran Desert of northern Mexico and Baja California.  Their stems can grow to be 15 feet (4.6 m) high and 8 inches (20 cm) in diameter. Stems of mature plants are covered with long, stiff, grey spines, which inspired its common name, "Old Man cactus." During the hot summer months, the beautiful pink flowers open after sunset and close before the following dawn. A mature Senita cactus can produce upwards of 3,000 flowers during the 3- to 5-month blooming season. The Senita moth, Upiga virescens, specializes in the pollination of the cactus' blooms. In fact, all the life stages of the moth are associated with the cactus in their mutualistic relationship.  Shown here are the closed, morning blooms of the Senita cactus. (Credit: NPS)

Some of the columnar night-blooming cacti indigenous to central Mexico are used as landscaping plants for southwest homes and businesses.  Their spectacular blooms remain open only one night and close by noon the following day. But, the many large, showy flowers are a common favorite throughout the desert regions. (Credit:  Linda & Dr. Dick Buscher)

The spectacular bloom shown here is from the Organ Pipe cactus (Stenocereus thurberi). One columnar cactus found only in a small region of the Sonoran Desert, the Organ Pipe cactus produces these beautiful blooms from April through August. The fruit produced by these flowers ripens into a juicy, sweet, red pulp that is a favorite food of both the indigenous people and the animals of the region. (Credit: NPS)

One of the last of the North American desert cacti to begin blooming each spring is the majestic, giant sentinel of the Sonoran Desert, the Saguaro cactus (Cereus giganteus). The beautiful, creamy-white, waxy, 3-inch-wide (8 cm) flowers with their golden-yellow centers make for a spectacular display across the barren Sonoran Desert landscape. Saguaros typically bloom in May and June, and their fruits ripen in late May through early July, providing much-needed food and moisture for desert creatures during the time of year when the Sonoran Desert receives little to no rain. (Credit:  Linda & Dr. Dick Buscher)

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Hot winds send dust streaking out to sea in a new astronaut photograph of Namibia's coast. 

These dust plumes are created by mountain, or berg, winds, according to NASA's Earth Observatory. Much like the Santa Ana winds in California, these winds flow from inland mountains. When air hits the mountain ranges, it rises and drops its moisture on the inland side of the slopes. After cresting, the now-dry air rushes downhill and encounters increasing atmospheric pressure, which causes it to contract — and in the process, heat up. 

This phenomenon is the reason for the "rain shadow" on the downwind, or lee, side of mountains, where the lee slope is much drier than the windward side. Berg winds are also known as Foehn winds or "snow-eaters," the latter because they melt snow on the lee side of mountains so rapidly. 

Foehn winds can fuel wildfires, particularly when they are strong. The berg winds of southern Africa can gust up to 62 mph (100 km/h), as can the Santa Ana winds of California.  

This astronaut image was snapped on June 21. Visible below the line of dust plumes, the Orange River can be seen flowing into the Atlantic Ocean. The river marks the border between Namibia and South Africa. Up the coast, a huge sandy expanse is the Namib Desert sand sea, a UNESCO World Heritage Site. This sand field covers more than 3 million hectares, and is frequently bathed in fog, the main source of water for the dune ecosystem. 

Editor's Note: If you have an amazing nature or general science photo you'd like to share for a possible story or image gallery, please contact managing editor Jeanna Bryner at LSphotos@livescience.com.

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

Winds sculpt the landscape of the Saharan coastline of West Africa. Here, the Atlantic Ocean meets arid land, and northerly winds push the sand in streaks parallel to the coast.

This image, released today (June 30) by NASA's Earth Observatory, was taken from the International Space Station on May 20. The astronaut's-eye-view reveals puffy clouds off the coast and ripplelike internal waves headed toward the shore. Internal waves are waves that occur almost entirely below the ocean's surface. Warm, less-salty water moves through colder, saltier water; these masses of water can be hundreds of feet tall. Some are more than 550 feet (170 meters) in height, according to researchers from MIT who are studying the phenomenon.

On the surface, internal waves often leave a footprint only a few inches tall, but sunglint, or sunlight reflecting off the surface, highlights these waves in photographs from space, according to NASA's Earth Observatory.

Other desert features stand out in this image. Silvery splotches reveal salt flats called sabkhas. Sand streaks parallel to the coast are caused by winds blowing from north to south, scouring the desert as they travel. Right off the coast, waves erode the sandy shore, staining the near-shore water aqua. 

As alien as this desert world may seem, the mark of human hands is visible in this photograph. On the left of the image, a light line running from the inland to the coast is a phosphate transport corridor. Roads, railways and conveyer belts move phosphate along this corridor, for use in making phosphorus, a major ingredient in fertilizers. Phosphorus is also used to make steel and to make compounds used in the manufacture of flame retardants, plastics and pesticides.

Editor's Note: If you have an amazing nature or general science photo you'd like to share for a possible story or image gallery, please contact managing editor Jeanna Bryner at LSphotos@livescience.com.

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A new satellite photograph shows an unnatural splash of color in the desert — bright blue evaporation ponds at a potash mine in Utah.

A potash mine sits aside the Colorado River about 20 miles (32 kilometers) west of Moab, Utah, in this snapshot taken May 13 by an instrument aboard the Landsat 8 satellite, according to NASA's Earth Observatory. The cluster of white shapes near the top center of the picture is the mine itself. The jewel-like blue areas are evaporation ponds, where the sun whisks away water pumped from the mine, leaving potash behind. 

Potash is a salt that contains water-soluble potassium. It is used mostly in fertilizers. The mine in this image, operated by Denver, Colorado-based Intrepid Potash, produces muriate of potash, or potassium chloride. This substance is the ingredient in 95 percent of all potash fertilizers, according to Agrow, a fertilizer marketing company in Australia.

To extract potash from the ground, workers drill wells into the mine and pump water down 2,400 to 4,000 feet (731 to 1,219 meters). There, the water dissolves potassium in the rock. The resulting brine is pumped out of the wells through extraction wells, which bring the liquid to the surface. From there, the brine goes to the evaporation ponds. The sun evaporates the water, leaving behind crystals of potassium and other salt, according to Intrepid Potash. [Shine On: A Gallery of Gorgeous Minerals]

These ponds measure 0.6 square miles (1.5 square kilometers), and are lined with rubber to keep the salts in. They get their bright blue color from a food-coloring-like dye that is added to prompt the absorption of sunlight. Once the potassium and salts are left behind, earth-scrapers gather the substance and send it off for processing.

Potash ore forms from the remnants of inland seas or lakes, according to the Earth Observatory. Over time, the waters dry out, leaving behind salts that become buried. The potash ore near Moab is about 300 million years old. The mine has been open since 1965, and Intrepid Potash expects to get at least 125 more years of production out of it before the potash ore runs out.

Similar mining techniques are used in other deserts, where sunlight and low humidity aid quick evaporation. In the Atacama Desert of Chile, for example, geometric patterns that look like art by the painter Piet Mondrian are actually evaporation ponds for nitrates and other minerals. Nitrates are another major fertilizer ingredient.

Editor's Note: If you have an amazing weather or general science photo you'd like to share for a possible story or image gallery, please contact managing editor Jeanna Bryner at LSphotos@livescience.com.

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

Northern China is infamous for dust storms that can sometimes choke Beijing in a yellow haze. A new satellite image shows one of these storms from above.

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua and Terra satellites captured this image on April 23, acording to NASA's Earth Observatory. This sandstorm affected the city of Dunhuang in northern China, turning the sky yellow-orange and forcing residents to don masks, the South China Morning Post reported.

Dust storms are so common in northern China and Mongolia that they have a name: Asian Dust. About 60 percent of the year's dust storms occur between March and May, according to the Taiwan Air Quality Monitoring Network. At this time of year, the ground is dry and free of snow, which allows strong surface winds to whip up clouds of dust and carry them for miles.

The storms exacerbate human-caused pollution from burning coal in China. As the country's economy grows, pollution (and its nasty health effects) has increased as well. This month, the Chinese government enacted a slate of new environmental laws meant to tackle the problem. The legislation strengthens fines against polluters and provides more pathways for environmental lawsuits.

Beijing is also fighting back against pollution, with a new requirement that construction sites in the city install cameras to monitor dust and rules against open vehicles carrying sand and other dusty materials. 

The dust storm spotted by NASA's satellites was driven by a large front moving east, according to the Earth Observatory. In some areas, visibility dropped to less than 160 feet (50 meters).

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

Desert blooms

Brittlebush (Encelia farinose) is a common plant of the Mohave Desert and Sonoran Desert of the American Southwest, including the warm inland valleys and coastal chaparral of southern and Baja California. With even a small amount of rain, these desert shrubs explode into a colorful display that changes the brown desert landscape into a sea of floral yellow.

A lush landscape?

These medium-sized perennial shrubs are a member of the Sunflower family (Asteraceae), and are believed to have a lifespan of around 20 years. Brittlebush has a woody base and takes on a rounded, umbrella shape with its many branches. The silver-green leaves tend to grow toward the ends of the multiple branches.

Tangle of branches

Brittlebush gets its name from the plant’s characteristic behavior during the long, dry seasons of the deserts. Without water, the leaves drop, resulting in a cluster of barren branches that are easily broken, or brittle. The plant has a shallow taproot and numerous lateral roots that wait in the rocky desert soil for the next rainfall, before leafing out once again and producing another burst of yellow flowers.

Hint of green

Young brittlebush sprouts once the rains return and typically, multiple bushes grow closely together, competing for the life-sustaining moisture. The young plants prefer a southern exposure and soil that drains well. Germination occurs after 10 days of consistent moisture. Germination is sporadic and some seeds will lie dormant for years before finally sprouting.

Natural protection

A mature brittlebush produces long, oval shaped and silver-green leaves that are covered with a white mat of short, silky trichomes (hairs). These hair-like structures help protect the leaves from both the heat and the cold. The trichomes’ white color reflects the intense desert sunlight and helps the plant limit the amount of water lost during the process of photosynthesis. They also trap any precious moisture that might be present in the air.

Full bloom

The most common blooming season for brittlebush occurs after the annual winter rains, between the months of March and June. The bright yellow flowers, produced at the tips of the long, barren stems, resemble miniature sunflowers.

Desert illusion

The beautiful disk-shaped flowers rise several inches above the mounded cluster of leaves, giving the illusion of a layer of yellow color floating above the gray-green plant.

Floral close-up

The flower heads of brittlebush are solitary. The disk-corollas vary in color from dark yellow-orange to purplish. The one-inch-long (2.5 centimeters) petals radiate from the head’s central disk, giving the flower its miniature sunflower appearance. A large brittlebush will produce hundreds of these showy, yellow flowers.

Transformation

This brown desert hillside of volcanic basalt is literally changed into a sea of yellow when hundreds of brittlebush plants bloom at the same time. Without additional rain, the hillside will regain its brown appearance within six weeks, as the flowers and leaves wither and fall upon the desert and hillside floor.

Pretty plants

During the desert spring, or even after a series of summertime thunderstorms, the common brittlebush becomes an agent of color — just add water and wait for the explosion of yellow. Southwest landscapers often use easy-to-grow brittlebush to add natural color to a desert landscaped home.

Sea of yellow

Once the rains stop and the heat of the desert returns, the beautiful yellow flowers quickly begin to fade. Local bees and beetles have pollinated the disk flowers of each bloom and thousands — if not millions — of seeds begin to mature.

Past their prime

The abundance of seeds produced by brittlebush scatter across the desert floor, and are dispersed between the rocks of the desert mountains. These seeds become a crucial food source for the desert animals. Birds and rodents consume most of the brittlebush seeds, seemingly aware that this is their last great feast until the rains of the summer monsoons come again in roughly four months.

Inciensio

The broken foliage of brittlebush gives off a distinct, yet pleasant, odor. Broken twigs ooze a golden resin sap that will quickly harden in the dry desert air to form hard, glistening globules. When the Spanish conquistadors and priests worked these lands, they would collect these globules and burn them as incense. Thus, the Spanish called the brittlebush "Inciensio."

Spring flowers

If you ever travel to this part of the world during the early days of spring, don’t expect the landscape to be dominated by the normal shades of brown. The dominant color of this land during these cool days of early spring is yellow, with the common brittlebush being a major contributor to this colorful annual display.

On a cold winter day in December 2007, a bulldozer flattened nearly 40 acres (16 hectares) of Inner Mongolia's Tengger Desert. It was the start of a unique experiment: For the first time, scientists would watch Earth's winds give birth to dunes.

Four years later, results from the giant Mongolian sandbox confirmed long-held models of sand dune formation, according to a study published today (Jan.12) in the journal Nature Geoscience.

Under the influence of the desert's seasonally varying wind patterns, which blow from the southeast and the west, the dunes grew at an angle of about 50 degrees to the overall wind direction. The dunes' alignment initially shifted back and forth with the changing winds, eventually converging to an average between the two wind patterns, the researchers found.

"It was very exciting when we realized that with the two wind directions we were getting a dune orientation that was oblique," said Clément Narteau, a study co-author and geomorphologist at IGP Paris. "It was quite fascinating to see that. It was just a pleasure to see that this kind of experiment can produce the expected results."

Modeling a messy world

While confirming a theory may seem like small potatoes to some, scientists who study dunes are thrilled by the results.

"They've done something quite brilliant," said Douglas Jerolmack, a geophysicist at the University of Pennsylvania, who was not involved in the research. "It's the kind of result that says our theoretical understanding is actually validated in the natural, messy world." [Sand Scenes: California's Shifting Dunes]

Dunes are one of the most difficult landscapes on Earth to re-create in a lab, Jerolmack said. Properly building a model means accounting for the full distance wind needs to pick up all the sand it can carry, typically hundreds of feet.

"At a minimum you need a wind tunnel hundreds of meters long, and it quickly becomes impractical to study dunes in a lab," Jerolmack told LiveScience's OurAmazingPlanet.

So scientists have relied more on math than miniature-scale dunes to explain how these spectacular landscapes form. But testing such models still remained a critical hurdle, because the massive sand piles hold key clues to climate on other planets and moons, as well as in Earth's past. The alignment of dunes reveals wind patterns in places where no other weather data exists.

"Results of this work — like the previous studies on this topic — are useful for interpreting a variety of modern bed forms on Earth (including eolian dunes, wave ripples, tidal sand waves), eolian dunes on Mars and Titan, and sedimentary rocks deposited by such bed forms," said David Rubin, a sedimentary geologist who was not involved in the study, in an email interview.

Rubin and colleagues at the U.S. Geological Survey developed the dune-formation model tested in the Mongolian dune study (called maximum gross bedform-normal transport).

Big sandbox

To link theory with the real world, Narteau and his collaborators at the Cold and Arid Regions Environmental and Engineering Research Institute in China decided to create their own dunes. They were testing what happens when dunes arise under seasonal wind conditions, which blow in different directions in Inner Mongolia's summer and winter. The model predicted dunes angled somewhere between the seasonal winds.

The team beveled three patches of desert. One bed was open to new sand, one was closed to incoming sand, and one was covered in gravel to prevent sand erosion. From the start, the dune crests, the tallest part of the dunes, were about 75 feet (23 meters) apart, a characteristic wavelength that stayed the same through the years. After a few years, the crests were angled about 50 degrees from the winds, as predicted by Rubin's theory.

"This is the validation of a theory that constrains the climate properties of dune formation," Narteau said. "The idea of flattening the desert to relate dune topography to wind is simple, but the simple idea is always the best."

The researchers plan further desert-flattening experiments to measure how quickly dunes grow and how that relates to wind speed. "We would like to get more into the details of the physics of sand dunes," Narteau said.

Email Becky Oskin or follow her @beckyoskin. Follow OurAmazingPlanet @OAPlanet, Facebook and Google+. Original article at LiveScience's OurAmazingPlanet.

Beep, beep! There's more camouflage for sneaky roadrunners and wily coyotes in the deserts thanks to rising carbon dioxide levels in the atmosphere, a new study finds.

Between 1982 and 2010, leaf cover on plants rose by 11 percent in arid areas, including the southwestern United States, Australia's Outback, the Middle East and some parts of Africa, the study found. The results were published May 15 in the journal Geophysical Research Letters.

The research confirms a long-held suspicion that one of the side effects of global warming will be lusher plant life. Plants pull carbon dioxide from the air — the gas is part of a chemical process called photosynthesis that plants use to make food. More carbon dioxide should lead to an average increase in vegetation across the globe, which studies have found in recent decades. But increased rainfall or changing temperatures could also be responsible for the new growth.

To weed out these bedeviling effects, researchers in Australia looked at desert plants, where carbon dioxide is expected to have the biggest impact on plants. The team adjusted for the shifts caused byprecipitation, air temperature, sunlight and land-use changes.

First, the researchers created a computer model that predicted carbon dioxide's "fertilization effect" on plants. The model estimated that plant foliage would increase by 5 to 10 percent during the 30-year study period. Atmospheric carbon dioxide rose 14 percent in this time.

With satellite imagery, the team tested their model against real-world changes between 1982 and 2010. The model proved a good match to the greener plants, yielding strong support for the hypothesis that carbon dioxide is driving plant growth, the researchers said.

But increasing carbon dioxide levels may do more than add more leaves to plants, lead study author Randall Donohue of the Commonwealth Scientific and Industrial Research Organization in Canberra said in a statement.

The carbon dioxide fertilization effect could shift the types of vegetation that dominate arid regions, he said. "Trees are reinvading grasslands, and this could quite possibly be related to the carbon dioxide effect," Donohue said. "Long lived woody plants are deep rooted and are likely to benefit more than grasses from an increase in carbon dioxide."

Even though a bump in carbon dioxide can boost plant growth, the climate changes that come with growing concentrations of the greenhouse gas have caused concern. For example, plants also need the right amount of moisture, and changing rainfall patterns sparked by global warming could counteract the positive effects of additional carbon dioxide.

"The effect of higher carbon dioxide levels on plant function is an important process that needs greater consideration," Donohue said.

Email Becky Oskin or follow her @beckyoskin. Follow us @livescience, Facebook & Google+. Original article on LiveScience.com.

Tien Shan mountains, China

Almost half the world's population gets its water from glaciers and rainfall in Asia's highest mountains and deserts. Geologist Aaron Putnam of Columbia University's Lamont-Doherty Earth Observatory, his father David Putnam, an archaeologist at the University of Maine at Presque Isle, and their colleagues recently visited some of these areas on study expeditions, snapping these striking photos.Above: Looking north toward the high Tien Shan mountains of western China. At center is the highest peak in the Tien Shan: Tomur peak (or Jengish Chokusu in Khirgiz).

Mountains in Bhutan

Snow on high peaks above Thampe Chhu, Bhutan.

Boulder sampling

Tshewang Rigzin (Department of Hydromet Services, Royal Government of Bhutan) and guides sampling boulder on moraine.

Weather station

Tshewang Rigzin (Department of Hydromet Services, Royal Government of Bhutan) and Aaron Putnam (Columbia) tinkering with a weather station.

Glacier, Bhutan

Prof. Summer Rupper (Brigham Young University) and colleagues descending Drukso Gangri after emplacing stakes that would monitor melt over the following year.

Glacier, Bhutan

Drukso Gangri ('Dragon-Tooth Glacier'), Bhutan.

Himalayan plateau

Rinchen Zoe plateau, Bhutan Himalaya.

Himalayan Blue Sheep

Himalayan Bharal ('Blue Sheep') on high cliffs near Tampe La.

Mountain camp

Camp beneath the high mountain pass of Tampe La.

Yak herders

Nomadic yak herders in the Nikka Chhu valley, Bhutan.

Himalayas

Looking north toward the spine of the Himalaya, featuring the high peaks of Makalu (right) and Everest (left).

Taklamakan Desert

Blowing sand in the Taklamakan.

Dry lake bed

Ancient lake bed of Lop Nor.

Tree cutting

Cookie cut from an ancient 'sub-fossil' poplar discovered deep in the Taklamakan Desert.

Desert poplars

David Putnam describing ancient poplars rooted in waterlain sediment surfaces in the Taklamakan Desert.

Desert sediments

Aaron Putnam investigating sediments that indicate the presence of water in the Taklamakan Desert.

Ancient shells

Shells associated with ancient, now-dry riverbeds in the Taklamakan Desert, south of the Tarim River.

Ancient sediments

Ancient waterlain sediments littered with wood being exposed from beneath migrating sand dunes.

Mud cracks

Ancient mud cracks on the surface of waterlain sediments in the Taklamakan Desert show that wet conditions prevailed in the past.

Desert dunes

Sand dunes in the Taklamakan Desert.

Map of the world

Red dots indicate the locations of our field sites where Putnam and colleagues are investigating past climate and glaciers.

Ocean garbage patches get a lot of attention, but a lot of trash is blowing across some of the most treasured and remote parts of America's desert wilderness, according to a new study out of the University of Arizona.

Biologist Erin Zylstra mapped and added up all the wind-dispersed plastic trash bags and latex balloons in two protected parts of the Saguaro National Park in Arizona. She was surprised to discover that these particular kinds of very mobile trash outnumbered desert tortoises and western diamondback rattlesnakes. Like in the oceans, the bags and balloons pose potential threats to wildlife.

The study, due to be published in the February 2013 issue of Journal of Arid Environments, grew out of surveys Zylstra was conducting on those same two reptile species as part of her studies at the University of Arizona, where she is now a doctoral student.

PHOTOS: The Great Atlantic Garbage Patch

"We were spending a lot of time surveying and we started to notice a lot of trash," Zylstra said. "Balloons are everywhere, once you start to look." The balloons were often found in clumps, tied with string and can become so degraded they look almost like lichens stuck to rocks, she explained.

"Western diamondback rattlesnakes are pretty common in the areas we studied," she said. "The fact that there is considerably more balloons than snakes was kind of shocking."

Like trash on the oceans and in coastal areas, winds seems to play a role in where trash collects in the desert as well. Zylstra found that the wind-blown bags and balloons in the two study areas, situated on opposite sides of the city of Tucson, reflected seasonal wind patterns in the region.

Because balloons are made of latex, they eventually decompose, although how long that takes in the desert is unknown. Plastic grocery bags, on the other hand, only break down if they are exposed to sunlight. Even then they only break into smaller pieces and become part of the water and soils, without actually changing into other compounds. That means they could mix with the water and food ingested by wild animals.

"Nobody really knows where those pieces of plastic bags end up," Zylstra said. "It's not known whether they have toxic effects." One possible concern is that the bags could end up in the few desert watering holes that animals of all kinds must share.

Another potential hazard for wildlife is the strings that come with the bunches of balloons, said Don Swann, a National Park Service biologist who works at Saguaro National Park.

"We see plastic bags and balloons in very remote places," confirmed Swann. This study finally put numbers on the amount of trash, which is very helpful, he said. It also showed how efficiently trash surveys can be incorporated into biological surveys.

"It's really great when researchers think outside the box," said Swann. "They can come up with insights that are valuable to us."

This story was provided by Discovery News.

A mysterious grid of dots spanning several miles of Western China's sand dunes like a giant chessboard may be the result of geological surveys for nickel mines, according to new analysis of satellite images of the area.

"In the satellite maps, we can see a man-made texture on the soil, a huge band which seems created by relatively small holes or mounds," wrote the study author, Amelia Carolina Sparavigna, a physicist at Italy's Polytechnic University of Turin, on Oct. 25 on the website arXiv.org, ahead of publication to a scientific journal. "This curious texture on the desert soil was probably produced by the pinpointing of geophysical [research]."

In 2010, Sparavigna started investigating Google Earth satellite images of China’s remote Taklamakan desert to study the textures carved into the sand dunes by the wind. In the process, the amateur archaeologist found possible paths around the ruins of an ancient Silk Road Kingdom called Loulan. For more than a thousand years, a sea of caravans laden with spices, silks and other Eastern goods passed through this arid outpost on the way to Europe.

While looking for traces of other vanished kingdoms in the area, Sparavigna discovered a mysterious grid of dots, like pinpricks laid out in the design of a chessboard, that spanned 4.8 miles (8 kilometers) across. [Photos of the Mysterious Sand Dune Shapes]

"The archaeological site is quite elusive in satellite maps, but I saw this long grid on the land," Sparavigna told LiveScience in an email.

The strange pattern was clearly man-made. In older imagery from Bing and Nokia Maps taken prior to 2004, the strange pattern wasn't visible, indicating the shapes appeared more recently.

Sparavigna then found an article in the Chinese press describing the discovery of large amounts of nickel buried under the dunes. She concluded the new shapes must be evidence of geological surveying done prior to mining the nickel reserves. Geologists often drill boreholes to determine the composition of mineral deposits below the surface.

This isn't the first time Sparavigna has analyzed satellite imagery to shed light on mysterious patterns. In 2011 she discovered strange patterns she claimed were geoglyphs in Peru, and has also weighed in on the symbolic meaning of Chinese army barracks from the 1960s.

Sparavigna thinks it may be a good idea to create a database of large-scale, man-made features like these throughout the world.

“In my opinion, it can anticipate mining activity and development of a region,” she said in an email.

Follow LiveScience on Twitter @livescience. We're also on Facebook & Google+. 

Taklamakan Desert Dunes

The sand dunes of the Western Chinese Taklamakan desert were once filled with caravans traveling the Silk Road.

China's Taklamakan Desert

Though little remains, several kingdoms arose in the desert to support the Silk Road trade

Taklamakan Desert From Space

In 2010, physicist and amateur archaeologist Amelia Carolina Sparavigna began looking for traces of these lost kingdoms in satellite images

Sand Dune Pattern

In the dunes, she found a mysterious grid of dots laid out like a chessboard. The patterns spanned 4.8 miles (8 kilometers) across

Sand Dune Pattern Up Close

By looking at old satellite images and news reports, Sparavigna learned that large nickel reserves had been found in the area. She deduced that the strange dots were drilling holes for geological surveys done before mining

Faint Dots

Another Google Earth view of the strange grid patterns found in China's desert.

Pattern Emerges

A closer view of the desert pattern reveals what appears as bands of dots.

The hot, dry Santa Ana winds currently whipping across southern California are linked to a dozen or so large wildfires that have consumed more than 300,000 acres (470 square miles, or about 1,200 square kilometers) of land in the area. The wind-driven flames have turned homes to ash and forced hundreds of thousands of people to evacuate.

Named after Southern California's Santa Ana Canyon, the Santa Ana winds are a seasonal phenomenon that occurs during the fall, winter and spring but which tends to peak in December. They can turn already-dry chaparral (think the "Wild West") into explosive fuel for wildfires, sending the resulting wildfires racing every which way.

Related: What are Chinook winds?

The gusts get their start as cool air hovering above the Great Basin — the dry and mountainous region between the Sierra Nevada and Rocky Mountains. This cool, high-pressure cell begins to sink, plunging downslope. Seen from above, the whole system rotates clockwise.

During the descent, the air warms up and loses much of its moisture. The result is a stream of hot, dry air blowing across the mountains and valleys of Arizona and southern California toward the Pacific Ocean.

Like water forced through a narrowing hose, the winds get a speed boost as they squeeze through tight passages between mountain ranges. When the winds reach at least 28 mph (46 kilometers per hour), the National Weather Service calls them Santa Ana winds.

Follow Life's Little Mysteries on Twitter @llmysteries. We're also on Facebook & Google+.

In a section of Southern California’s Santa Rosa Mountains, plants appear to have been migrating uphill in recent decades, but the reason is controversial.

An early study attributed this shift to changes in local climate, possibly due to urbanization or natural cycles, but akin to changes expected as a result of human-caused global warming.

But another research team set out to refute that, saying this claim overlooked a crucial dynamic in this area: fires.

The debate also brings into focus two potentially loaded words: climate change. The words hold a certain political importance these days, and both research duos admit the phrase has the potential to create a bias toward studies that purport to show the effects of global warming.

However, while one team says the first study is an example of the problem, the other maintains knowledge of this issue motivated them to conduct a rigorous analysis, which tied changes only to local conditions, not directly to global warming. [10 Climate Change Myths Busted]

Shifting plants

In 2006-2007, graduate student Anne Kelly, now at the University of California, Irvine, retraced a 1977 survey of vegetation cover at sites that progressed at regular intervals from desert scrub near sea level up to a conifer forest nearly 8,400 feet (2,560 meters) high.

By comparing the two surveys, Kelly and Mike Goulden, also of the University of California, Irvine, found that of 10 dominant species, nine had shifted uphill and one downhill. Across all 10 species, the average shift was 213 feet (65 m) uphill.

These shifts occurred uniformly across the elevations, but overall plant cover stayed constant, they reported. Meanwhile, during this 30-year period, the area was subject to droughts of unprecedented intensity, and average temperature increased by 0.7 degrees Fahrenheit (0.4 degrees Celsius).

The nature of the plant shifts — which also included declines at the already warmer, drier low elevations — fit into patterns expected for a change driven by drought or warming, they argued in a study published in 2008 in the journal Proceedings of the National Academy of Sciences.

Climate or fire

In the more recent study, Dylan Schwilk, of Texas Tech University, and Jon Keeley, of the U.S. Geological Survey and the University of California, Los Angeles, resurveyed some of the sites focusing on a single plant, a shrub called desert ceanothus, and found the same pattern; the shrub was becoming less abundant at lower elevations and more so higher up.

They had a suspicion that the area’s fire history could potentially explain the results, or at least, cast the local climate change conclusion into doubt.

The duo used rings in the plants' stems to determine when the last fires hit, since the plants don't sprout until after a fire. They calculated how many of the plants died off over time as they grew and fought for space.

The desert ceanothus stems suggested the highest-elevation sites burned about 91 years ago, while the rest burned later, 65 years ago. This could account for the shift in vegetation, at least for the desert ceanothus, since the higher-elevation sites would have had the most stable populations, having already recovered after the fires, Schwilk told LiveScience. [Raging Western Wildfires in Photos]

"Their data is not wrong, it is the interpretation," Schwilk said of the work done earlier by Kelly and Goulden.

Their work shows the first study passed over an important aspect of the ecology of this place, he said. 

Kelly and Goulden don't dispute the fire history the other team has reconstructed, but they do stand by their original results.

"We didn't need the fire history to make our paper stand, we had all of this other evidence," Goulden said.

For instance, the nature of the shift they documented in the plants fit into patterns expected for a change driven by drought or warming, they argued.

The bigger climate controversy

In Schwilk's eyes the original study represents a broader problem. He sees the consequences of the politicization of climate science: a desire to publicly affirm its reality has created a bias favoring work that shows an effect of global warming, even if the conclusion isn’t warranted. 

"People expect it to be happening, it’s political. … There is a bit of a mentality of 'it's important to get this data out,'" said Schwilk, who describes himself as a "firm believer" in climate change and its effects.

Kelly and Goulden point out they blamed local climate change, although their work could have implications for human-caused global warming.

Goulden does agree, at least to a point, with Schwilk: "There is a tendency on the part of some scientists and a little bit of pressure maybe to hype their work, sometimes to go for the more sensational story," Goulden said. "Because of that, we tried really hard actually to word our PNAS paper carefully."

Schwilk and Keeley's work on the fire history of the sites was published earlier this year in the journal PLoS ONE.

FollowWynne Parry on Twitter@Wynne_ParryorLiveScience @livescience. We're also on Facebook & Google+.

On the western edge of the Asian country of Turkmenistan, a vast desert meets the world's most expansive inland water body, the Caspian Sea.

This natural-color Landsat 7 satellite image, taken on June 16, 2000, shows the sand-covered Dardzha Peninsula sticking out in to the Caspian. The peninsula is a landscape of sand dunes and salt flats that extends from Turkmenistan's Garagum (or Karakum) Desert, which covers most of the country.

Dunes on the peninsula are long, linear features stretching mostly along the north-south direction. Toward the east, the dunes transition to level, sandy plains. Along the peninsula’s southern edge lies a network of partially submerged dunes, interspersed with shallow, salty lakes. These dunes separate the Dardzha from a neighboring peninsula, the Cheleken.

A river known as the Uzboy used to flow through the Garagum Desert toward the Caspian Sea. Exactly when the river dried up is a matter of debate, but when the river was active, its estuaries periodically flooded. The flooding deposited vast quantities of sand, eventually forming the Dardzha Peninsula. Today, winds blowing over the Garagum Desert can pick up dust that is later deposited on arable lands of the Volga River Valley, impeding agriculture, according to a NASA statement.

Falling water levels in the Caspian Sea, partially driven by human activities such as river damming, contributed to the buildup of silt on the Dardzha Peninsula, especially after 1960. The average surface level of the Caspian is 89 feet (27 meters) below sea level.

South African Ocean Bloom

Off the coast of South Africa, near where the South Atlantic meets the Southern Indian Ocean, a massive summer phytoplankton bloom colored the waters with a swirl of turquoise, green and white in late December 2011. Although this circular bloom has the appearance of a precious antique gaming marble, it is actually the result of millions of tiny plant-like organisms (phytoplankton ) which are growing where nutrient-rich waters mix together.

[Full Story: Earth as Art: An Ocean Bloom]

Stunning Natural Beauty

Our Blue Marble gives us amazing and unexpected art. This natural beauty supplies some of the most breath-taking views around. Here you will find a few of its offerings.

Arizona's Painted Desert

In northern Arizona lies an expanse of arid, erosion-prone badlands made of multicolored mudstones and clays. This Painted Desert stretches from the Grand Canyon in the northwest to the Petrified Forest National Park in the southeast.

[Full Story: Earth as Art: Arizona's Painted Desert]

Idhan Murzuq Sea of Sand

In southwestern Libya, near the borders of Algeria and Niger, lies a sand sea known as Idhan Murzuq (also Sahra Marzuq) that rarely receives water from either sky or land. The extreme desert's complex dunes are shaped by dry winds. But extending from the northeast quarter, a corridor of sand lines what used to be a river channel: Wadi Barjuj.

[Full Story: Earth as Art: Sea of Sand]

Lake Dundas Encrusted Lake

Salt lakes of assorted sizes occur throughout southwestern Australia, and one of the larger ones is Lake Dundas. Located about 130 kilometers (80 miles) inland from the coastal city of Esperance, Lake Dundas occupies a region of low rainfall and abundant sunshine. This salt-encrusted lake presents a complex face to satellite sensors, with plentiful islands poking above the water line.

[Full Story: Earth as Art: A Salt-Encrusted Lake]

Cloud Swirls over the Indian Ocean

As citizens of northern countries ponder sculpted snow and ice, or icings for baked goods, the summer skies over the southern oceans offered their own vision in white in the early winter of 2011. The brush strokes of bright holiday swirls were made by winds and atmospheric eddies moving over the far southern reaches of the Indian Ocean.

[Full Story: Earth as Art: Indian Ocean Clouds]

Madagascar's Bombetoka Bay

On the northwestern coast of Madagascar, the salty waters of the Mozambique Channel penetrate inland to join with the freshwater outflow of the Betsiboka River, forming Bombetoka Bay. Numerous islands and sandbars have formed in the estuary from the large amount of sediment carried in by the Betsiboka River and have been shaped by the flow of the river and the push and pull of tides.

[Full Story: Earth As Art: Madagascar's Bombetoka Bay]

From NASA's Earth Observatory:

In southwestern Libya, near the borders of Algeria and Niger, lies a sand sea known as Idhan Murzuq (also Sahra Marzuq) that rarely receives water from either sky or land. The extreme desert’s complex dunes are shaped by dry winds. But extending from the northeast quarter, a corridor of sand lines what used to be a river channel: Wadi Barjuj.

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this natural-color image on December 7, 2011. Sand dunes stand out especially in the northwestern part of Idhan Murzuq, though the entire sand sea contrasts with its rockier surroundings.

A study published in 2008 and relying on data from multiple NASA sensors reconstructed Libya’s geology and hydrology over the past 7 million years. Over that span, Libya intermittently experienced humid, rainy conditions. One finding was that Wadi Barjuj was probably a tributary in a river system that drained into the Mediterranean Sea though eastern Libya.

Rivers naturally migrate and change over time, and Wadi Barjuj was no exception. Volcanoes began to rise northeast of Wadi Barjuj, and sometime between 5 million and 2 million years ago they blocked the river’s path. With its route blocked, the river system stopped flowing to the sea and instead began feeding a lake. Researchers have named it Lake Megafazzan, estimating its maximum size at about 135,000 square kilometers (52,000 square miles). During humid periods of the past, they explained, Libya was “a veritable lake district.”

Massive as it was, Lake Megafazzan did not cover all of southwestern Libya. Today’s Idhan Murzuq was likely above water during most of the past several million years. It was not, however, a sand sea throughout that entire period. Researchers found evidence of sand seas starting to form after volcanoes blocked the path of Wadi Barjuj and after the massive lake began backing up toward the southwest.

In southern Afghanistan, shifting sand dunes flow across the huge, sandy desert known as the Registan. When the winds constantly blow from the same direction over relatively flat terrain with a small to moderate amount of sand, the sand will pile up in crescent-moon shaped dunes, whose thin tips point in the direction of the wind flow, according to a NASA statement.

Called barchan dunes, these dunes will migrate across the desert surface as sand grains on the crest of the dune are toppled by the wind and spill down the leeward face of the mound. As the pile of sand on the leeward side (the side protected from the wind ) gets larger, gravity eventually topples the growing pile, moving the dune's leading edge slowly forward.

Large barchan dunes, such as those found in White Sands National Monument in New Mexico, often migrate between 8 and 15 feet each year.

• 'Stone Forests' of the Sahara
• Sand Grains in African Desert 1 Million Years Old

Mysterious walls built on the arid lands of the Middle East seem to have played a role in the slaughter of whole herds of wild gazelles by prehistoric tribes of herder-farmers, possibly leading to the animal's extinction in those herders' areas.

The bones of a slaughtered herd of gazelles were discovered at a site called Tell Kuran, located in the Khabur River Basin in northeastern Syria. A mound found in this area, an important source of archeological discoveries since the 1930s, was recently discovered to contain the 6,000-year-old layer of bones from about 100 gazelles.

"It was clear, once it was excavated, that it had accumulated through a single short episode, based on the fact that the bones were very concentrated and in a thin archeological layer," study researcher Guy Bar-Oz, of the University of Haifa in Israel, told LiveScience.

Hunting herds

Bar-Oz, and co-researcher Melinda Zeder of the Smithsonian Institution, studied these bones in detail to understand how they all ended up deposited together. The bones weren't weathered as if they had amassed over time, so it's likely they were all deposited together after the slaughter of an entire herd. Based on the site's proximity to these long wall formations, the gazelles were most likely slaughtered at these formations, called desert kites.

Researchers speculate that the animals were driven into the kites — the arms of which can extend about 1,000 meters (more than 3,000 feet) long — by up to a few dozen hunters, possibly with the help of herding dogs. The two arms of such formations would funnel the animals toward a circular formation at the end, for the slaughter. 

The bones found at the site were from about 100 gazelles, representing the age and gender diversity of a normal migrating herd. There were a large number of foot bones, which indicate that the gazelles were skinned and dismembered here. "Animals were moving into those kites, jumping and being injured and being slaughtered," Bar-Oz said. "If complete herds were killed, eventually it leads to their local extinction."

Slaughtered to extinction

Scientists had suspected these prehistoric wall formations had been used in some way to herd animals for slaughter. At the time, local cultures were mainly dependent on domestic herds and agriculture, and so the gazelle meat was likely used to supplement these other food sources.

However, previous excavations of several of these kites in the area produced no evidence of large animal graves.

This kite-slaughter event would probably happen only about once a year, Bar-Oz said, during the gazelles' late-summer migration south. It was most likely a ritual slaughter, with religious connections.

"They had no refrigerators; they would have to consume this meat in a very short time," he told LiveScience. "This is why you'd connect it to some ritual get-together or feasting. At these certain times, you have a lot of meat and can share it with other people."

Earlier tribes in the area hunted a gazelle one or a few at a time. This mass slaughter of gazelles could have been the start of their demise. Gazelles in some other areas disappeared after firearms become more common for hunting in the 19th and 20th centuries.

Tell Kuran was discovered in the early 1990s, but the gazelle bones weren't described until recently.

You can follow LiveScience staff writer Jennifer Welsh on Twitter @microbelover. Follow LiveScience for the latest in science news and discoveries on Twitter @livescience and on Facebook.

The contrasting landscapes of the American West are on display in this image taken by the European Space Agency's Envisat satellite. Verdant California lies to the left of the images, separated by the white, snowy peaks of the mountains from the brown of Nevada's deserts.

California boasts a 840-mile-long (1,350 kilometers) coastline , valleys and numerous mountain ranges that run generally parallel to the Pacific Ocean. The Coast Ranges, a series of mountains that includes the Diablo and Santa Cruz Mountains, extend along much of the coast.

The flat, broad depression to the east of the Coast Ranges is the 450-mile-long (720 km) Central Valley. Its northern half referred to as the Sacramento Valley receives more rainfall and is lush, while its southern half called the San Joaquin Valley has a more arid climate. Centred on agriculture, the valley's productivity relies on irrigation from surface water diversions and groundwater pumping from wells.

The Sierra Nevada mountain range (snow-capped, east of Central Valley) runs along California's eastern edge. Lake Tahoe is located in the Sierra Nevada on the CaliforniaNevada border.

It is no coincidence that the land west of the Sierra Nevada is lush, while the land to its east is desert. The mountain range forces moisture from easterly-moving clouds to be released before reaching Nevada.

Nevada's landscape comprises sandy deserts, snow-capped mountains and basins. Most of the state lies within the Great Basin Desert. Covering an arid expanse of some 190,000 square miles (492,000 sq km), it is the largest U.S. desert. The Great Basin is noted for its internal drainage system, in which precipitation never reaches an outlet to the sea.

Also visible in the image are the California cities of San Francisco (the whitish area on the peninsula surrounding the San Francisco Bay, center left) and Los Angeles (sprawling grey area, bottom left).

• The West: One of Earth's Most Mountainous Regions
• Infographic: Tallest Mountain to Deepest Ocean Trench
• Southwestern United States Spied from Space

Although desert sands might seem to shift ceaselessly under the wind, scientists now find the grains of sand in the Namib Sand Sea in Africa have dwelled there for at least a million years.

Analysis of desert sands could shed light on how climate might have changed over the millennia, researchers explained.

The vast Namib Sand Sea, which covers roughly 13,125 square miles (34,000 square kilometers) along the coast of Namibia, is one of the world's oldest and largest sand deserts. However, little is known about the origin of its sands — whether they come from remote sources or local sediments. This uncertainty holds true with other large deserts as well, largely because one sand dune looks much like another.

"While a lot of climate research has focused on the polar regions, deserts and particularly sand deserts remain relatively understudied and poorly understood, despite the fact that millions of people live in arid and semi-arid areas threatened by desertification," researcher Pieter Vermeesch, a geologist at the University of London, told OurAmazingPlanet.

To track the movement of sand grains across the sand sea, Vermeesch and his colleauges measured levels of uranium and lead in the sands to confirm that their primary source is apparently the Orange River at the southern edge of the Namib desert. They also analyzed radioactive isotopes produced by cosmic rays (high energy particles that rain down on Earth from space), which allowed them to estimate the amount of time the sand had been present in the region.

"All samples were collected on the crests of large — up to 200 meters (656 feet) high — dunes, quite a strenuous workout," Vermeesch recalled.

The researchers found that it took at least a million years for winds to blow sands across the sand sea.

"While geologists have long known that the Namib Sand Sea is a very old landform, we had no idea that the individual sand grains spend so much time inside it," Vermeesch said. The time the sands spent in the sand sea was 10 times longer than he had expected.

Sand seas only exist in hyper-arid environments, and so their presence or absence can reveal key details about ancient climates. "The residence time of sand grains in a sand sea is a proxy for the sensitivity of desert areas to climate change," Vermeesch explained.

It remains uncertain whether the sand dunes in the Namib Sand Sea were continuously active across the past million years or whether they went through cycles of stasis and movement. "To answer this question, additional samples will be required from the heart of the desert," Vermeesch said.

Ultimately, Vermeesch wants to use these techniques to investigate the Sahara. "Because of the political instability in the area, relatively little is known about the Sahara and the sediments contained in it," he explained. "This is unfortunate, because a better understanding of the Sahara would lead to a better understanding of human evolution, of the spread of humans out of Africa, of the negative feedback mechanisms that dust production in the Sahara has on global warming, and so forth. Important discoveries are waiting to be made in this part of the world."

The scientists detailed their findings online Oct. 31 in the journal Nature Geoscience.

• The Harshest Environments on Earth
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