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World's Oceans Remain Largely Mysterious


NEW YORK - The ocean covers 70 percent of the Earth's surface, but on this World Oceans Day (June 8, 2010) scientists say they still know shockingly little about the mysterious deep blue sea.

With 95 percent of the ocean unmapped, more is known about the moon's surface than the ocean depths, said aquatic filmmaker Fabien Cousteau, grandson of ocean diving pioneer Jacque Cousteau. In fact,12 men have stepped foot on the moon, but only two have been to the Mariana Trench, the deepest part of the ocean at roughly 7 miles (11 kilometers) deep.

The few forays to the bottom of the ocean have revealed that "we were wrong about life on Earth," said David Guggenheim of the Ocean Foundation, speaking Friday at the World Science Festival here. As these deep-sea expeditions have revealed, life on Earth can even exist miles below the ocean's surface and under the most extreme conditions. Scientists hope that in the coming years new technologies that are under development may allow man to dive deeper and probe further into the ocean abyss solving some major mysteries about our own planet.

Exotic creatures revealed

Researchers have discovered exotic creatures known as extremophiles thriving on the ocean floor where it was once thought to be impossible for life to live due to the lack of sunlight and extreme pressure at these depths. Gangly red and white creatures known as giant tube worms live several miles deep and can grow almost 8 feet (2.4 meters) long. Giant tube worms live in bunches and can withstand extremely high temperatures and sulfur levels, but exactly how they do this is still a mystery.

Not all deep-sea animals are bizarre life forms. Scientists have found thriving deep-sea shrimp colonies that are somehow unfazed by the harsh ocean floor environment. Deep-sea octopus species, see-through cucumbers, and yeti crabs are other recently discovered strange sea creatures.

"We're just beginning to be awakened to the majestic diversity of marine life," said marine biologist Sylvia Earle of the U.S. National Oceanic and Atmospheric Administration (NOAA).

An estimated 1 million species of marine organisms live in the world's oceans, but that number is little more than a guess, since only 230,000 marine organisms have been discovered, according to the Census for Marine Life.

Ocean scenery coming into focus

The undersea geology is just as striking and mysterious as the marine life that dwells around it. Ocean explorers have discovered lakes and pools on the ocean floor that are known as brine pools. These deep-sea bodies of water are three to five times saltier than the ocean itself, so the two bodies of water do not easily mix, which creates lake surfaces and shorelines.

Undersea exploration has also revealed that the largest waterfall is not Angel Falls in Venezuela, which is 3,212 feet (979 m) tall, but is instead found under the ocean. Beneath the Denmark Strait that separates Iceland from the east coast of Greenland is an estimated 2.2-mile (3.5-km) tall waterfall, where cold and dense water from the seas north of the Denmark Strait cascade down into the depths of the Irminger Sea.

Sea explorations have also revealed violent volcanic eruptions that occur every single day at the sea bottom, Guggenheim said. Adding to the volatile ocean floor are deep-sea hotbeds that can reach temperatures up to 750 degrees Fahrenheit (400 Celsius). These ocean floor hotbeds are home to stunning organisms that rival life in tropical rainforests.

Satellite measurements are only now revealing the ocean's depth and volume, but there are huge gaps in the data. Ship-based sonar and other measurements have mapped such a small percentage of the ocean floor that it would take a single ship 200 years (or 10 ships 20 years) to measure all the ocean-floor depths, according to published U.S. Navy estimates.

Mysteries remain

Deep-sea chemistry, such as the formation of what are called hydrates, is another ocean mystery currently under investigation. Hydrates form when natural gas leaks from the seafloor and fuses with water to form the same tiny crystals that are hindering efforts to cap the oil leak in the Gulf of Mexico. Oil companies are investigating their potential as an energy source, but little is known about this ice-like material except that it only forms at low temperatures and high pressures in the deep sea.

Perhaps the biggest mystery of the ocean is how to study it in the first place. The main reason is the ocean is just too deep. If Mount Everest the tallest mountain on Earth were transported to the bottom of the Mariana Trench, there would still be 6,811 feet (2,076 meters) of water above its peak. [Graphic: Top of the World to the Bottom of the Sea ].

To descend to the bottom of the ocean, researchers need technologies that can withstand crushing pressures. At the bottom of the Mariana Trench, the pressure is over one thousand times the standard atmospheric pressure at sea level. Not since 1960, when U.S. Navy Lieutenant Don Walsh and Jacques Piccard reached the bottom in 1960 has anyone else visited.

Billions of dollars are spent to explore what lies above the ocean, but little is invested toward understanding the deep sea, researchers said at the World Science Festival. The total investment in ocean exploration is only one one-hundredth of the amount spent on space exploration, said NOAA's Sylvia Earle.

New deep-diving robots that can study the ocean floor are under development, but the arsenal of underwater robots is not large enough, nor are there enough people working on these technologies, said oceanographer David Gallo of Woods Hole Oceanographic Institute.

Following in the footsteps of SCUBA-diving pioneer Jacque Cousteau is an exciting new type of wearable submarine think Iron Man's suit, but for underwater diving known as an Exosuit. Under development by Nuytco Research, these next generation pressure suits for deep diving will allow divers to reach depths of 2,000 feet (610 meters) Earle herself reached 1,200 feet (355 m) deep in a prototype.

However, this depth still barely reaches below the ocean's surface and the suit is at least a year away from completion.

As Fabien Cousteau said in a behind-the-scenes look at his new film Oceans, deep sea explorers need an array of tools that inspires gadget-envy so they can truly become "fish among fish." 

Brett Israel was a staff writer for Live Science with a focus on environmental issues. He holds a bachelor’s degree in biochemistry and molecular biology from The University of Georgia, a master’s degree in journalism from New York University, and has studied doctorate-level biochemistry at Emory University.