In-depth study of the deep sea

Michael Richardson Straits Times 26 Mar 12;

MOST people live and work on land. Some journey by air, or go out to sea. But all return to the land.

Our terrestrial view of the world defines exploration. As we spread and settle on land that was once wilderness, there seems little left on Earth to explore.

We know that space is still a vast, mysterious frontier. But we seldom think of the oceans as watery terra incognita, blinkered as we are by our land view.

However, the seafloor is an extension of the land. It has mountains, valleys and plains, although they are hidden by seawater. Little is known about the deep recesses of either the sea or the seabed.

Yet the oceans and seas play a vital role in sustaining life. They cover nearly three-quarters of Earth's surface, provide around half the oxygen we breathe, and are an important source of protein for a rapidly growing world population.

We need to know much more about the oceanic world because pollution, overfishing and acidification from excessive absorption of carbon dioxide produced by burning fossil fuels and clearing forests are changing the seas, perhaps irrevocably and certainly in ways that make them less productive.

The deep sea, below about 200m, is by far the world's largest habitat, providing more than 80 per cent of the space for life on Earth to exist, from giant whales to minute phytoplankton.

This is why the audacious descent to the deepest place in the ocean (planned) by multimillionaire Hollywood film director James Cameron, of Titanic and Avatar fame, is important. It will stimulate much-needed popular interest and scientific research into oceanic life.

Lowered from a surface support ship by cable in a unique, high-tech one-person capsule designed to withstand extreme pressure and cold, Mr Cameron's target is Challenger Deep, the bathtub-shaped depression at the lowest point of the Mariana Trench in the Pacific Ocean west of the Philippines, 11,033m under the surface.

By early yesterday, the ship was positioned over Challenger Deep awaiting suitable weather to launch the diving capsule with Mr Cameron on board.

The trench is a mega-scale submerged Grand Canyon that stretches for 2,400km along the seabed in a subduction zone where the Pacific plate slides below the Mariana plate, creating a volatile region of earthquakes and volcanoes.

Only one manned submersible, sent down by the US Navy in 1960, has reached the bottom of Challenger Deep. It stayed for just 20 minutes. Since then, only unmanned remotely operated vehicles - the Japanese Kaiko in 1995 and the US Nereus in 2009 - have been down there.

Mr Cameron is filming documentaries in collaboration with the National Geographic Society. He is also working closely with the Scripps Institute of Oceanography, the University of Hawaii and other scientific groups.

His sub's scientific tools include a water sampler, a sediment collector, a 'slurp gun' for catching animals without hurting them, and a robotic manipulator arm. Also being deployed are three 'landers' to perform complementary research. The landers sink to the sea floor unattended, then rise on a timer or remote signal.

The deepest level a fish has ever been recorded is about 8,370m. Farther down, the main interest is in rock and sediment samples that could help researchers answer questions about subduction processes and the way fluids and mud are cycled through Earth's mantle.

Bacteria and other organisms plucked from the depths will enable scientists to understand how they withstand such extreme conditions.

Until now, the world's most advanced submersibles were built by the governments of the United States, China, France, Russia and Japan. But as budgetary constraints bite state oceanic research, wealthy private explorers in partnership with scientists are taking up the challenge.

Just behind Mr Cameron is adventurer and entrepreneur Richard Branson. His Virgin Oceanic arm has developed a solo manned sub that has small wings and is designed to 'fly' along the bottom of trenches that criss-cross the ocean bed at the boundaries of tectonic plates, instead of going straight down to the depths like the Cameron capsule.

Starting later this year, the Branson engineering team and its scientific collaborators plan to journey to the deepest part of each of Earth's five oceans. Less than 3 per cent of the seafloor has been explored, and none of the deepest points of the main oceanic trenches has been reached by manned submersibles, except for Challenger Deep.

Virgin Oceanic says it aims to provide a vertical sequence of sea life by using the sub in the southern Mariana Trench to record and collect specimens from its axis over 10km deep and then up the face of a nearby fault escarpment to near the surface, documenting changes in ecosystems along the way.

This could provide the first complete record of biological diversity from top to bottom in the world's oceans.

The writer is a visiting senior research fellow at the Institute of Southeast Asian Studies.

James Cameron reaches deepest spot on Earth
Associated Press Yahoo News 25 Mar 12;

HONOLULU (AP) — Hollywood icon James Cameron has made it to Earth's deepest point.

The director of "Titanic," ''Avatar" and other films used a specially designed submarine to dive nearly seven miles, completing his journey a little before 8 a.m. Monday local time, according to Stephanie Montgomery of the National Geographic Society.

He plans to spend about six hours exploring and filming the Mariana Trench, about 200 miles southwest of the Pacific island of Guam.

"All systems OK," were Cameron's first words upon reaching the bottom, according to a statement. His arrival at a depth of 35,756 feet came early Sunday evening on the U.S. East Coast, after a descent that took more than two hours.

The scale of the trench is hard to grasp — it's 120 times larger than the Grand Canyon and more than a mile deeper than Mount Everest is tall.

Cameron made the dive aboard his 12-ton, lime-green sub called "Deepsea Challenger." He planned to collect samples for biologists and geologists to study.

"It's really the first time that human eyes have had an opportunity to gaze upon what is a very alien landscape," said Terry Garcia, the National Geographic Society's executive VP for mission programs, via phone from Pitlochry, Scotland.

The first and only time anyone dove to these depths was in 1960. Swiss engineer Jacques Piccard and U.S. Navy Capt. Don Walsh took nearly five hours to reach the bottom and stayed just 20 minutes. They had little to report on what they saw, however, because their submarine kicked up so much sand from the ocean floor.

"He is going to be seeing something that none of us have ever seen before. He is going to be opening new worlds to scientists," Garcia said.

One of the risks of a dive so deep is extreme water pressure. At 6.8 miles below the surface, the pressure is the equivalent of three SUVs sitting on your toe.

Cameron told The Associated Press in an interview after a 5.1 mile-deep practice run near Papua New Guinea earlier this month that the pressure "is in the back of your mind." The submarine would implode in an instant if it leaked, he said.

But while he was a little apprehensive beforehand, he wasn't scared or nervous while underwater.

"When you are actually on the dive you have to trust the engineering was done right," he said.

The film director has been an oceanography enthusiast since childhood and has made 72 deep-sea submersible dives. Thirty-three of those dives have been to the wreckage of the Titanic, the subject of his 1997 hit film.