Why is the krill so important to the survival of every other animal that makes Antarctica its home?

Antarctic krill -- Euphausia superba -- form the base of the food chain in the Southern Ocean that surrounds the Antarctic continent. It is the most productive protein source on earth.

No animal 'makes its home' on the Antarctic continent.

Krill provide a bait source to catch fish. Fish is a food source common taken in Antarctica due to lack of other food sources and the soil has no ability to farm with. Also Krill are important food sources to seals and penguins.