Thursday, December 2, 2010

Antarctic Krill

Antarctic Krill (Euphausia superba) are the largest of all the krill, small, semi-transparent crustaceans that can be found the world over. They grow up to two inches long, and have a slight hint on red on their backs.

It is estimated that there are over 500 million tonnes of Krill in the ocean, and that that biomass is the most for any multi-celled creature on the entire planet. They swim in dense swarms that can contain 10,000-30,000 individuals per square meter.

(Image Source)
Antarctic Krill feed on phytoplankton, which is abundant due to updrafts of nutrients from the cold waters. Phytoplankton feed from nutrients and the sun, and Krill feed on them, meaning they lose very little energy as they are so close to the source on the chain. This make Krill a desirable meal for larger animals because they too will lose very little energy. Baleen Whales feed almost exclusively on Krill, scooping up these swarms in a mouthful. Good thing female Krill lay up to 10,000 eggs at a time!

Unfortunately, Antarctic Krill numbers, and the numbers of other Krill species, have dropped nearly 80% since the 1970s. Increased Carbon Dioxide levels have already proven to be a huge detriment to the species. A continued downward trend could have drastic implications for the large marine animals that depend on them for food.

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