Warming temperatures and the disappearance of a critical link in the food chain are turning the once-teeming ocean waters near San Diego into a dead zone, a researcher says.
John McGowan of the Scripps Institution of Oceanography at La Jolla, said that since 1951 the water temperature off San Diego has increased by two to three degrees Fahrenheit and the population of zooplankton, a critical part of the food chain, has declined by 80 percent.
The lack of zooplankton leaves little food for many fish and birds and those, too, have been seriously hurt, McGowan said Thursday.
McGowan said the water temperature increase is robbing surface waters of the nutrients, such as nitrates and phosphates, that plant plankton needs to survive. The zooplankton feed on the small plant plankton.
McGowan reported his findings in the journal Science on Friday.