A much higher biodiversity than thought

May 17, 2007 06:53 GMT  ·  By

If you think that the deep cold waters of Antarctica have no life, forget it.

A new research of the Antarctic Benthic Deep-Sea Biodiversity Project (ANDEEP) has found over 700 new species in the depths of the Southern Ocean (the Indian, Atlantic, and Pacific Oceans surrounding Antarctica).

Amongst the species found on the seafloor at depths of 2,300 to 19,700 feet (700 to 6,000 meters) there were heart-shaped sea urchins, carnivorous sponges and giant sea spiders the size of dinner plates.

"We used to think that, with decreasing nutrient and food availability, there might cause a decrease in biodiversity toward the Poles," said lead researcher Angelika Brandt, a marine biologist at the University of Hamburg in Germany.

"There were a lot of species we hadn't seen before, because so little was known before we started," said co-author Brigitte Ebbe, a marine biologist at the German Center for Marine Biodiversity Research in Willhelmshaven.

Three ANDEEP expeditions investigated between 2002 and 2005 the fauna and flora of the Weddell Sea, east of the Antarctic Peninsula. The international project supports the Census of Marine Life (CoML) program, involving thousands of researchers who want to make a detailed record of sea life by 2010.

"In other oceans the number of species drops the deeper you go, but in the Southern Ocean we found the opposite trend." said co-author Katrin Linse, a marine biologist at the British Antarctic Survey.

300 species of isopod, a various group of crustaceans related to garden wood lice, were found in the shallow Antarctic waters and some were even pelagic (they could swim).

"With the deep-sea samples, suddenly the number of isopods rocketed up to at least a thousand," said Linse.

Moreover, the deepest part of the seafloor to the north displayed even more isopod species, between 60 to 70 degrees south latitude. The majority of the newly discovered species are very small (under 0.2 inches (5 mm)) and ghostly white.

"It's so deep and dark down there, you dont need any color," said Linse.

This research was also the first to investigate the DNA of the Southern Ocean's deep-sea species and it was shocking to find that the similar-looking specimens of foraminifera (shelled amoeba-like protozoa) encountered at the North and South Poles belong to the same species, based on genetic analysis.

"Even more surprising was the discovery of a much stronger gene flow in foraminifera from the Antarctic to the Arctic, but not vice versa." said Brandt.

This was linked to the deep Antarctic water flow towards north, delivering the deep water masses in the other oceans.