| Summary: | The Antarctic krill (Euphausia superba) is a two-inch long, shrimp-like crustacean that lives in the Southern Ocean surrounding Antarctica. It is one of many euphausiid species found around the world, but it is unique in that this species is considered to be the 'keystone' species of the Southern Ocean ecosystem. A keystone species is a single species that can have an extremely dominating influence on the composition of a community, and may swing the whole equilibrium of that community if that species is removed (Ricklefs 1997). E. superba is unusual, in that a keystone species is often a predator at the top of the food web, but instead krill is a member of the zooplankton community, only one energy level away from the bottom Of the food web. However, krill holds a crucial position in the food web that makes it the only intermediate form the autotrophic organisms that create the biological energy of the Southern Ocean and many of the Southern Ocean predators, including the largest animals in the world - the baleen whales. As a result, many species of the Southern Ocean are directly or indirectly affected by any variation in the distribution and/or abundance Of Antarctic krill. The aim of this literature review is to investigate the distribution and migration patterns of Euphausia superba, what environmental factors may affect this distribution, and then conclude by briefly describing how this relates to the distribution of Southern Ocean animals higher up the food web. The Antarctic krill (Euphausia superba) is a two-inch long, shrimp-like crustacean that lives in the Southern Ocean surrounding Antarctica. It is one of many euphausiid species found around the world, but it is unique in that this species is considered to be the 'keystone' species of the Southern Ocean ecosystem. A keystone species is a single species that can have an extremely dominating influence on the composition of a community, and may swing the whole equilibrium of that community if that species is removed (Ricklefs 1997). E. superba is ...
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