THE ANTARCTIC ECOSYSTEM Antarctic seas are extremely productive because phytoplankton grows abundantly during the extended daylight of summer and feeds huge populations of krill. Krill are a key animal in this ecosystem, as food for top predators: whales, penguins, and seals. Winters have little light, no phytoplankton growth, and extremely cold temperatures, but a complex food web links a great variety of ocean animals. (Illustration by Jayne Doucette, WHOI Graphic Services)
