Antarctic krill population has declined by 80% [View all]

[Ichingcarpenter]

The Antarctic krill population has declined by 80% since the 1970s, and without them the entire ecosystem of the Southern Ocean will collapse.




Antarctic krill feed on algae and phytoplankton that are suspended in the water column. They are preyed upon by nearly every Antarctic predator that exists. And if a predator doesn't eat krill, it feeds on the ones that do. A penguin's diet consists of nearly 100 percent krill. Blue whales rely on krill for almost all of their dietary requirement. During the summer months, an adult blue whale eats up to 40 million krill in a single day to fulfill its 1.5 million kilocalorie nutritional needs. Antarctic krill is the keystone species in the Southern Ocean, and without it, the ecosystem would collapse.

Antarctic krill use intensive searching and rapid feeding techniques to take advantage of high plankton concentrations. Krill form dense schools that move horizontally in the water column when feeding. Krill spend their days avoiding predators in the cold depths of the Southern Ocean. At night, they drift up toward the surface to search for phytoplankton


Recent studies show Antarctic krill stocks have dropped by as much as 80 percent since the 1970s. Scientists attribute this decline in part to ice cover loss caused by global warming. This ice loss removes ice algae from the Southern Ocean which is a primary source of food for krill. NASA satellite data reveals that there has been continuous ice loss from Antarctica since 2002—more than 100 cubic kilometers of ice per year.






http://weeklysciencequiz.blogspot.dk/2012/09/the-keystone-species-of-southern-ocean.html