Without krill, most of the marine animals in Antarctica would disappear. So what are they?

Krill are crustaceans, each about 5 cm long. In addition to their diet of phytoplankton, they have the ability to scrape ice-algae from the underside of ice formations. In turn, they are on the menu for hungry squid, penguins, seals and whales. In short, krill form an integral part of the Antarctic ecosystem.

Together, krill would number in the billions, yet their numbers are decreasing. Why? One reason may be the melting and loss of ice formation due to increased global temperatures. Another reason is humans' greed. Krill oil, high in omega-3 fatty acids, is packaged as health medication to maintain healthy cholesterol. How many krill are worth the lif ...