Warming could affect ocean food chain

HALIFAX, Nova Scotia, July 30 (UPI) -- Scientists say the amount of ocean plankton, the foundation of the aquatic food chain, has declined over the past century as ocean temperatures have risen.

Researchers say the first comprehensive global look at plankton changes over a long time scale shows Phytoplankton, tiny marine plants, declining in the upper layers of ocean water by about 1 percent a year, the BBC reported Friday.

"What we think is happening is that the oceans are becoming more stratified as the water warms," said research leader Daniel Boyce from Dalhousie University in Halifax, Nova Scotia.

"The plants need sunlight from above and nutrients from below; and as it becomes more stratified, that limits the availability of nutrients," he said.

The reduction and its possible effects is worrying to many scientists, they say.

"Phytoplankton ... produce half of the oxygen we breathe, draw down surface CO2, and ultimately support all of our fisheries," Boris Worm of the Dalhousie team said.

"An ocean with less phytoplankton will function differently," he added.