Scientists: Plankton, vital to much life on Earth, in sharp declne

WASHINGTON (AP) — Despite their tiny size, plant plankton found in the world's oceans are crucial to much of life on Earth. They are the foundation of the bountiful marine food web, produce half the world's oxygen and suck up harmful carbon dioxide.

And they are declining sharply.

Worldwide phytoplankton levels are down 40 percent since the 1950s, according to a study published today in the journal Nature. The likely cause is global warming, which makes it hard for the plant plankton to get vital nutrients, researchers say.

The numbers are both staggering and disturbing, say the Canadian scientists who did the study and a top U.S. government scientist.

"It's concerning because phytoplankton is the basic currency for everything going on in the ocean," said Dalhousie University biology professor Boris Worm, a study co-author. "It's almost like a recession ... that has been going on for decades."