Editor's Note: The decade-long Census of Marine Life project, involving thousands of scientists from around the world, has produced discoveries of thousands of weird creatures living in the depths of the sea where the sun doesn't shine. Many of the strange new species were announced Sunday, Nov. 22 (Read the news story). Below, more about the mission, its challenges, and why the research is being done.
Revealed via cameras towed deep in the sea, sonar and other technologies, a stunning 17,650 species are now known to thrive in the darkness of the deep sea, scientists announced today. Each voyage of exploration into the watery depths is expensive, dangerous work.
"Every deployment is a trip into the unknown, with often seasick scientists struggling to work amid high winds and 10 meter (33 feet) swells," said researcher Mireille Consalvey of the New Zealand National Institute of Water and Atmospheric Research, project manager for the Global Census of Marine Life on Seamounts.
The deep sea "is the Earth's largest continuous ecosystem and largest habitat for life. It is also the least studied," said researcher Chris German of Woods Hole Oceanographic Institution, co-chair of Biogeography of Deep-Water Chemosynthetic Systems project.
There are lots of challenges to exploring something as immensely large as the deep sea. To plumb its mysteries, the scientists employ high-tech devices, including remotely operated vehicles (ROVs), autonomous underwater vehicles (AUVs), and submarines, as well as more traditional equipment, such as trawls, cores and dredges that need several miles of cable to reach the seabed. For instance, roughly 7.5 miles (12 km) of cable were recently needed to trawl down to about 3 miles depth (4,800 meters) on the Porcupine Abyssal Plain in the Northeast Atlantic.
The researchers don't just use devices to explore life in the abyss. A Southern elephant seal tagged by scientists recently dove down some 1.5 miles (2,388 meters) from the surface. At that depth, water pressure is roughly equal to 240 times the air pressure at sea level. The human eardrum can rupture at 10 meters.
The number of scientists working on the deep-sea census project number 344 and span 34 nations. By the time their work concludes in 2010, they will have collectively fielded more than 210 expeditions.
Incredible diversity under threat
The researchers discovered the mud of the abyssal floor contains a startling amount of biodiversity.
"Some scientists have likened deep mud's biodiversity to that of tropical forests," said Robert Carney of Louisiana State University, co-leader of the Continental Margin Ecosystems on a Worldwide Scale project. "In college I was taught that high biodiversity is a function of habitat diversity — many nooks and crannies. It is, however, hard to imagine anything as monotonous, nook-less and cranny-less as deep-sea mud."
But these voyages show "many species live there," Carney added. "To survive in the deep, animals must find and exploit meager or novel resources, and their great diversity in the deep reflects how many ways there are to adapt."
The vast majority of creatures collected in mud from the abyssal plains are new to science, with most of the animals in the deep-sea mud at only a few millimeters in size, hiding among the sediment particles.
"The abyssal fauna is so rich in species diversity and so poorly described that collecting a known species is an anomaly," said researcher David Billett of United Kingdom's National Oceanography Center. "Describing for the first time all the different species in any coffee cup-sized sample of deep-sea sediment is a daunting challenge."
For example, of some 680 specimens of flea-like crustaceans known as copepods collected on a recent cruise to the southeastern Atlantic, only seven could be identified — 99 percent were new to science. And among hundreds of species of animals about the size of an earthworm collected in different areas, 50 to 85 percent were unrecognized.
This biodiversity could prove valuable.
"There's a lot of interest in bioprospecting there — pharmaceutical companies are really very interested in what deep-sea fauna have to offer, as they often produce unusual compounds," explained Paul Snelgrove, an oceanographer from Memorial University of Newfoundland in Canada.
However, the deep sea is now vulnerable to humanity.
"A lot of us who work on deep sea systems tended to think a decade ago that they were relatively safe from human perturbations, but it turns out now there evidence humans having measurable effects on deep sea ecosystems, largely through climate change activities that affect the amount of organic material setting into the deep ocean, as well as changes in acidity," Snelgrove said. "There is also evidence of pollutants creeping deeper and deeper into the ocean."
Any impact on the deep sea could have prolonged effects. "There's evidence that a lot of things in the deep sea grow very slowly and live a long time," said Michael Vecchione, director of the National Oceanic and Atmospheric Administration's Fisheries National Systematics Lab at the Smithsonian. "If we do damage their ecosystems, it can take a long time to recover, if they ever recover."
These deep-sea explorations make up five of the 14 field projects of the Census of Marine Life, an international science project started in 2000 that unites thousands of researchers worldwide. In October 4, 2010, the project will detail their findings in their final report, "The Census of Marine Life 2010: A Decade of Discovery."
- NEWS STORY: The Deep-Sea Creatures Discovered
- Gallery: Rich Life Under the Sea
- Gallery: Small Sea Monsters