A diverse group of creatures beneath an Antarctic ice shelf could give pause to researchers who infer past ecological conditions from fossils found in such sediments.
In December 2003, researchers drilled a hole through the 480-meter-thick Amery ice shelf in Antarctica to get a look at the ocean bottom. At the drill site, 100 kilometers from open ocean, they expected to see a barren seafloor. How wrong they were.
Video of the ocean bottom at a depth of about 775 m revealed a wealth of creatures, says Martin J. Riddle, a marine biologist at the Australian Government Antarctic Division in Kingston, Tasmania. On the 2-square-meter patch of seafloor within camera range, the team identified more than two dozen familiar-looking species of invertebrates, including sponges, mollusks, sea urchins, and a sea snail.
Most of the creatures typically filter food and nutrients from the water or scavenge the ocean bottom. Scientists hadn't expected currents to bring much food to