But the Southern Ocean is one of the world's most productive marine ecosystems, home to huge numbers of penguins, seals, and bottom plants, and a major supplier of nutrients carried to other parts of the world by undersea currents. Altering an Ecosystem Little is known about the effect of UV-B on marine life, particularly the microscopic algae called phytoplankton that form the foundation of the undersea food chain. These tiny plants capture the sun's energy through photosynthesis, providing food for microscopic animals. They are eaten by krill, which sustain the Antarctic's abundant seals, penguins, and baleen whales. Less phytoplankton means less food for these animals to eat.
Researchers say it's clear that UV-B harms Antarctic microbes.
Neale has predicted that phytoplankton photosynthesis declines by as much as 8.5 percent under the worst conditions. It also damages the DNA of marine bacteria and the larvae of starfish and urchins, they say. And it even alters ocean chemistry, creating potentially dangerous substances in the water itself. The tricky part is estimating how damage to one group of organisms might affect others above or below it in the food chain. Ocean ecosystems are extremely complicated and poorly understood.