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Difference between revisions of "Antarctic krill"
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Antarctic krill directly use the minute phytoplankton cells, which no other animal of krill size can do. This is accomplished through filter feeding, using the krill's highly developed front legs, providing for an efficient filtering apparatus: the six thoracopods (legs attached to the thorax) form a very effective "feeding basket" used to collect phytoplankton from the open water. In the finest areas the openings in this basket are extremely tiny. In lower food concentrations, the feeding basket is pushed through the water for over half a metre in an opened position, and then the algae are combed to the mouth opening with special setae (bristles) on the inner side of the thoracopods. | Antarctic krill directly use the minute phytoplankton cells, which no other animal of krill size can do. This is accomplished through filter feeding, using the krill's highly developed front legs, providing for an efficient filtering apparatus: the six thoracopods (legs attached to the thorax) form a very effective "feeding basket" used to collect phytoplankton from the open water. In the finest areas the openings in this basket are extremely tiny. In lower food concentrations, the feeding basket is pushed through the water for over half a metre in an opened position, and then the algae are combed to the mouth opening with special setae (bristles) on the inner side of the thoracopods. | ||
===Ice | ===Ice algae raking=== | ||
Antarctic krill can scrape off the green lawn of [[ice | Antarctic krill can scrape off the green lawn of [[ice algae]] from the underside of the [[pack ice]]. Krill have developed special rows of rake-like setae at the tips of the thoracopods, and graze the ice in a zig-zag fashion. One krill can clear an area of a square foot in about 10 minutes. It is relatively new knowledge that the film of ice algae is very well developed over vast areas, often containing much more carbon than the whole water column below. Krill find an extensive energy source here, especially in the spring. | ||
==Biology== | ==Biology== | ||