Tiny krill are deep-sea divers

For the first time, scientists have found tiny shrimplike krill at depths of up to 3,000 meters (nearly 10,000 feet) off the Antarctic coast. Krill serve as the main course for squid, whales, penguins, and other marine creatures. Up to this point, krill were thought to hang out within 150 meters (500 feet) of the ocean surface. The results will force scientists to overhaul their ideas about krill habits and ecology, say two British Antarctic Survey scientists who discovered the deep-diving krill.

The scientists say they were amazed to find adult krill, including pregnant females, feeding at such great depths. Video from a remotely-controlled vehicle shows the krill smacking headfirst into the muck on the seafloor, then swimming back through the cloud of material they kicked up to eat the nutrients in the cloud.

These krill probably don't represent an undiscovered population, the two say. Instead, the krill appear to migrate up and down the water column. The results appear in this week's issue of the journal Current Biology.