(Related: "Video: Antarctica Diving Opens Up World of Strange Creatures" [January 31, 2006].)
Around 300 species of isopod, a diverse group of marine crustaceans related to garden wood lice, live in the shallow Antarctic waters.
However, they look different from wood lice. One common family of isopods can even swim.
"With the deep-sea samples, suddenly the number of isopods rocketed up to at least a thousand," co-author Linse said.
In addition to the wealth of species found in the oceans near Antarctica, lead author Brandt noted the deepest part of the seafloor, farther north, revealed even more isopod species, from 60 to 70 degrees south latitude.
Most of the new species are very small—less than 0.2 inches (about 5 mm)—and nearly all are ghostly white.
"It's so deep and dark down there, you dont need any color," said co-author Linse.
The ANDEEP cruises were also the first to look at the DNA of the Southern Ocean's deep-sea species.
"The great advantage in the Antarctic is that the water column is cold all the way up," said Brandt, "so we can bring material up on deck and extract DNA before it becomes damaged by heat."
The study revealed that similar-looking specimens of foraminifera, single-celled amoeba-like creatures found at the North and South Poles, are genetically the same species—a shock to scientists.
Even more surprising, said Brandt, was the discovery of a much stronger gene flow in foraminifera from the Antarctic to the Arctic, but not vice versa.
That's because deep Antarctic water flows northward, supplying much of the deep water in other world oceans.
The study appears in tomorrow's issue of the journal Nature.
Colin Summerhayes, executive director of Scientific Committee on Antarctic Research (SCAR), was not involved in the study.
He noted that the Ecology of the Antarctic Sea Ice Zone project, another recently-completed program, also turned up high biodiversity under Antarctic sea ice.
"We now see that the notion of a latitudinal decrease in biodiversity towards the South Pole is rubbish," Summerhayes said.
"This current study confirms the trend we found in communities beneath the sea ice."
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