SCIENCE REPORTER
Researchers exploring the deep ocean have discovered hundreds of new species that live beyond the reach of the sun's rays, evidence there may be more biodiversity in ocean mud than in the tropics.
They took part in five missions to progressively deeper realms, using towed cameras, sonar and other equipment to inventory the creatures of the abyss. The challenging field work was part of the Census of Marine Life, an ambitious 10-year effort to chart the diversity, range and abundance of life in the oceans. It is an international project, involving 344 scientists from 34 countries, including Canada.
Some of the animals the scientists observed or collected are alchemists: They turn gases or chemicals that would be toxic to most living things into nutrients. This includes a tubeworm that leaked crude oil when it was yanked from the ocean floor.
Others feed on the bones of dead whales. But many more depend on the detritus from the upper levels of the ocean that slowly drifts down. That meagre livelihood could be diminished as the planet warms, Paul Snelgrove, a researcher at Memorial University in St. John's, said.
As the top layer of the ocean warms up, it becomes more stable, he said. That means less mixing with the next layer, and less material that will eventually sink to the bottom.
"You are going to starve them, in a sense," he said.
The deep sea is the Earth's largest continuous ecosystem and largest habitat for life. It is dark and cold down there, about 3 C, and most of the sea floor is mud, said Bob Carney, a professor of oceanography at Louisiana State University.
But there is so much of it, with so many rare species of small clams, crustaceans worms and other creatures, that it may have greater biodiversity that the tropics, he said.
"To survive in the deep, animals must find and exploit meagre or novel resources, and their great diversity in the deep reflects how many ways there are to adapt.''
Take, for example, the "wildcat" tubeworm that was pulled from the bottom of the Gulf of Mexico with a robotic arm.
These tubeworms have hard bodies, much like human fingernails, and feed on hydrogen sulfide, a gas that is produced as petroleum is broken down. Except at very low levels, hydrogen sulfide is deadly to most animals.
But this worm was feasting.
"When we pulled the worm up, the sticky oil went streaming away. The water was about 5 degrees so it looked like molasses," Dr. Carney said.
Despite the lack of light, there are brightly coloured corals and sponges in the deep ocean. One of the rarest finds was a yellowish-green species of cucumber.
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OLDER THAN ARISTOTLE
Some of the animals that live in the deep ocean have extremely long lives.
"We've been studying tubeworms that are 100 to 200 years old, says Bob Carney of Louisiana State University.
Memorial University's Paul Snelgrove says deep water corals have been found that are over 4,000 years old.
"They were around before Aristotle was born," he says.