Posted on 11/04/2004 8:46:19 AM PST by cogitator
Food Shortages Threaten Antarctic Wildlife
Antarctic whales, seals and penguins could be threatened by food shortages in the Southern Ocean. Numbers of Antarctic krill (Euphausia superba), a shrimp-like crustacean at the heart of the food chain, are declining. The most likely explanation is a dramatic decline in sea-ice. The results are published this week in the journal Nature.
Sea-ice is a vital feeding ground for the huge number of krill in the Southern Ocean. The new research shows that krill numbers have dropped by about 80% since the 1970's. Less sea-ice during the winter is likely to be the cause and may explain declines seen in several species of penguins.
Lead author Dr Angus Atkinson from British Antarctic Survey, says: "This is the first time that we have understood the full scale of this decline. Krill feed on the algae found under the surface of the sea-ice, which acts as a kind of 'nursery'."
"The Antarctic Peninsula, a key breeding ground for the krill, has warmed by 2.5°C in the last 50 years, with a striking decrease in sea-ice. We don't fully understand how the loss of sea-ice here is connected to the warming, but we believe that it could be behind the decline in krill."
The implications are commercial as well as scientific, as the Southern Ocean is a valuable resource for fisheries. Thousands of tourists are also attracted to Antarctica to enjoy the spectacular wildlife, most of which feed on krill.
By knowing how the environment affects this unique food web, we can predict how it will respond to future change.
The people at junkscience.com speculate that the rebound in the whale populations might be responsible. Whales munch on krill. Whale populations were low in the 1970s compared with today. So 1970s krill levels may be artifically high. Perhaps today's measure is a more reasonable estimate of krill numbers than that in the 1970s. No one knows.
What's an environmentalist to do? Playing God is just so hard!
BTT!!!!!
I was thinking that way too. Maybe "Save the whales" has been so successful that it is turning krill into an endangered species. Or it could be that whales have followed the rest of us mamals into becoming obese over eaters.
"Women and Minorities hit the hardest".
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