Brrrr! How well do you think you would grow if you lived in a freezer? Adam Marsh, a marine biochemist at the University of Delaware, and colleagues Rob Maxson and Donal Manahan from the University of Southern California, have discovered an important reason why the pincushion-like Antarctic sea urchin (Sterechinus neumayeri) can function so well in the polar seas surrounding the Earths frozen continent.

The Antarctic sea urchin demonstrates a remarkable economy, a super energy-efficiency in its metabolism. Despite frigid water temperatures and little available food, its babies can synthesize proteins more efficiently than any other organism recorded to date. The scientists findings are reported in the March 9 edition of Science.

All animals expend about 30% of their energy just turning over proteins, says Marsh. But the embryos and larvae of the Antarctic sea urchin can perform this vital metabolic process using 25 times less energy than the rest of us. Thats really amazing, he notes, especially considering the extreme environment in which these larvae live and an almost non-existent food supply.

The Antarctic sea urchin resembles a red pincushion, about 5 inches in diameter, with long spines extending from its round shell. It lives on the seafloor and uses its spines and sucker-tipped tube feet to move about. Baby sea urchins are spawned during the summer months and take about a year to develop from embryo to larva to juvenile a stage that is a miniature version of the adult.

To collect sea urchins for their study, Marsh and his colleagues traveled periodically to McMurdo Station, a research outpost on Ross Island, Antarctica. The scientists cut holes in the 8-foot-thick sea ice and inched down a tow rope into the freezing water wearing insulated diving suits that covered all but their faces. Their lips and cheeks would go numb after 60 seconds of exposure.

Once the sea urchins were collected from the se
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Contact: Tracey Bryant
tbryant@udel.edu
302-831-8185
University of Delaware
7-Mar-2001