It's World Ocean Day. The international celebration is designated by the United Nations as day to take action to protect marine ecosystems. KPBS Environment Reporter Ed Joyce tells us UC San Diego research shows the health of the oceans has declined in recent decades.
Scientists say pollution, declining fisheries and climate change are causing severe deterioration of the oceans.
Andrew Dickson is a marine chemistry professor at the Scripps Institution of Oceanography.
He says the world's oceans are becoming more acidic.
"There's fewer fish," Dickson says. "There's more obvious traces of man's activities if you analyze the water. CO2 is one of those. It's a huge one, because we're talking about hundreds of billions of tons of CO2 dissolving in the oceans since the industrial revolution began."
Dickson says the ocean is growing more acidic because of the burning of fossil fuels. He estimates the acidity has increased 30 percent in the last 100 years.
He says more research is needed to determine the long-term affects of acidity on ocean ecosystems and marine species.
But Dickson says early studies show corals and shellfish may be irreparably damaged by the change in ocean chemistry.
