TURNING SALTWATER SEAS INTO ACID OCEANS: THE THREAT TO OUR SEAFOOD SUPPLY

Clams – those bivalve mollusks that are so popular with seafood lovers – could disappear from the dining table. According to Mark Green, Ph.D., professor and chair of Environmental Science at St. Joseph’s College of Maine in Standish, we’ve put so much carbon dioxide into the atmosphere it’s dissolving into the surface layer of the ocean and turning into an acid strong enough to destroy young clams within days of exposure. The implications for fisheries, marine ecosystems and seafood supplies worldwide will be devastating.

Green is an oceanographer and self-described oyster grower. He also is a pioneer in ocean acidification research, garnering international attention and three major grants from the National Science Foundation. His data was cited in a 2010 industry letter to a U.S. Senate Subcommittee hearing on the Environmental and Economic Impacts of Ocean Acidification. With his most recent grant, Green is focusing research on the impact of acidification on microscopic larval clams in several Maine estuaries.

According to Green, ocean acidification has been on the radar screen for little more than five years. However, we’ve been putting carbon dioxide into the atmosphere 20 times longer than that. Over the last 100 years the level of acid in the ocean has increased by 30 percent. And it’s getting worse. Declares Green, “We’re changing the chemistry. The ocean can’t keep up with the amount of acid that we’re putting in.”

Focusing his research on small, larval and juvenile-sized bivalves, Green paints a grim picture. When exposed to ocean acidification, pitting on the outside of a shell is visible within 24 hours; by 72 hours the shell is corroded; between two and three days, there is almost a complete destruction of the shell. He is unequivocal when he says, “There’s no debate about ocean acidification. It’s real. It’s happening very, very quickly.” He further cautions that change needs to happen now. “Ocean acidification is a real issue with dire consequences if we don’t do something.”

While there is no single solution to ocean acidification, Green points out that there are many smaller solutions that can slow its rate, all of which involve reducing carbon emissions. This means finding low-carbon energy sources, increasing car fuel efficiency, limiting deforestation, using alternative energy – all of which are achievable with political will and determination. He challenges, “We certainly have the technical resources and the scientific minds. We just need people to step up to the plate and demand action.”

Dr. Green is the featured speaker at the Fall 2011 Ocean Environment Lecture Series hosted by MERI in Blue Hill. He will speak on Ocean Acidification: Survival of Marine Ecosystems and Seafood on Thursday October 20. Green’s lecture begins at 7 p.m., preceded by a reception at 6 p.m. All lectures in the series are free and open to the public.

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