Biodiversity: Plumbing the Secrets of the Ocean Depths
Stephen Leahy (Inter Press Service)
BROOKLIN, Canada, - Incredible new forms of life have been discovered around super-hot 400 degree C seafloor vents, as well as under 700 metres of Antarctic ice, by the 20th scientific expedition of the Census of Marine Life of 2006 now underway.
For the next few weeks, scientists aboard the German research icebreaker Polarstern will explore the Antarctic seafloor, which has been hidden by thick layer of ice for more than 5,000 years. It is an unprecedented opportunity brought about the unexpected collapse of the Larsen B ice shelf along the Antarctic Peninsula four years ago. Now 3,250 sq kms of sea floor is accessible.
"Preliminary research shows there is a huge amount of diversity of life there," said Ron O'Dor, a senior scientist with the Census of Marine Life (CoML).
"This is our first chance to take a good look at a region no one has explored before," O'Dor told IPS.
The CoML is a global partnership of 2,000 scientists from 80 countries with a 10-year mandate to investigate life in the seas until 2010. Earlier CoML expeditions to the Antarctic have uncovered an astonishing community of marine life shrouded beneath 700 metres of ice -- 200 kms from open water.
"We're finding more new species than known species," O'Dor said.
The great Southern Ocean is the least explored but perhaps the most important, as it is the link between all the other oceans of the world.
Climate change is warming the Southern Ocean and ice is melting in many parts of the Antarctic. Census scientists are trying to determine how the warming will affect marine species in the region, O'Dor says.
The Polarstern, the research flagship of the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany, is the 20th Census expedition of 2006. It is also the first of 14 Antarctic expeditions being launched as part of the International Polar Year 2007-2008.
The International Polar Year is a major scientific effort to better understand the Polar Regions because they exert a large influence on the global climate and are being hit hardest by climate change. The three fastest warming regions on the planet in the last two decades have been Alaska, Siberia and parts of the Antarctic Peninsula.
"It's been an exciting year for the Census. The progress we've made shows that the first-ever census of marine life can be done," said Jesse Ausubel, a programme manager for the Sloan Foundation, a Census sponsor.
What the Census has proven is that life exists everywhere in the oceans, even under the most extreme conditions, from super-cold to extremely hot, Ausubel said in an interview.
"We're not finding any 'empty deserts' in the oceans," he said.
Three kilometres deep in the equatorial Atlantic Ocean, a crack in seafloor ejects fluids directly from the Earth's core, at an unprecedented marine recording of 407 degrees C -- a temperature that would easily melt lead. In total darkness, under tremendous pressure and with wild extremes of temperature ranging from two degrees C to 400 degrees C, life abounds.
In this incredible atmosphere, Census researchers found shrimp, mussels, clams and other life forms living on the periphery of the hydrothermal vents. Somehow they survive the extreme variations in temperatures and tolerate the high concentrations of heavy metals from the vent fluids.
"We've found more than 500 new species around vents like these," said Chris German, a scientist with the Southampton Oceanography Centre in Britain.
The first hydrothermal vent was found only 30 years ago, and about 100 are now known.
"Species are remarkably different from each other in different ocean basins," German told IPS.
A recent expedition to the first vent ever explored in the South Atlantic revealed completely different fauna than those at vents along the mid-Atlantic ridge several thousand kms to the north.
The opportunities for finding new species are nearly boundless as there may be 1,000 vents in the world's oceans, German says.
Not only adapted to extremes in temperatures, many of these species use chemicals and seawater for photosynthesis because of the absence of light.
"There is nothing comparable on the surface of the earth, not even in hot springs," said Fred Grassle, chair of the Census Scientific Steering Committee.
Animals have somehow evolved to use the heat energy and chemicals pumped out of the deep sea vents to survive and thrive.
"The CoML expeditions show the marvels remaining in the ocean to protect, and indeed still to discover," Grassle said in an interview.
At another hydrothermal vent a few hundred kilometres west of the U.S. Pacific northwest state of Oregon, Census microbe hunters found 20,000 kinds of bacteria floating in a single litre of seawater.
In the Coral Sea, a region off the northeast coast of Australia, researchers also discovered a type of shrimp believed to have gone extinct 50 million years ago. Nicknamed "Jurassic shrimp", it rivals the find in South Africa and Indonesia of the coelacanth, a prehistoric fish once known only through fossils.
Census analysts examining the future of marine animal populations also compiled the first-ever global assessment of the extent of coral reefs within Marine Protected Areas. Less than two percent of coral reefs worldwide are protected from extraction, poaching and other major threats.
Deep-sea surveys have also determined that 70 percent of the world's oceans are now shark-free. In an extensive study, scientists working on Census projects found that although many sharks live down to 2,000 metres, they fail to colonise deeper, putting them within easy reach of fisheries.
"The historical studies of the CoML agree with recent studies showing steep declines in most wild populations of every marine animal that people eat," said Grassle. "The past richness of the oceans in many near-shore regions is hard for today's people to believe."