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How 50-year-old carbon dioxide haunts shellfish

Carbon dioxide absorbed by the ocean causes acidification that harms shellfish. How exactly does it happen? Researchers at OSU are looking into that.

Carbon dioxide absorbed by the ocean causes acidification that harms shellfish. How exactly does it happen? Researchers at OSU are looking into that.

Researchers at Oregon State University are delving into the impacts of ocean acidification on shellfish.

Scientists already know the oceans are overloaded with carbon dioxide, and in the Northwest the resulting acidification is threatening oyster survival.

In one of the new studies, OSU scientists will try to determine the threshold at which acidification begins to harm oysters, clams and mussels – including those that are grown commercially. Principal investigator George Waldbusser of OSU’s College of Oceanic and Atmospheric Sciences and his colleagues will explore exactly how that harm occurs.

“We’ll be developing a novel experimental approach to tease apart just what component of acidification is actually affecting the organism,” Waldbusser said. “For example, decreased pH may affect the internal acid-base balance of an organism, but the correlated decrease in calcium carbonate saturation state may also alter the stability of their mineral shells. Scientists know very little, to date, about specific modes of action triggered by acidification.”

Waldbusser received a four-year grant of nearly $2 million from NSF to lead the project. He will work with Burke Hales and Brian Haley from the university’s College of Oceanic and Atmospheric Sciences, and Chris Langdon, who directs the Molluscan Broodstock Program at OSU’s Hatfield Marine Science Center in Newport.

They will develop their experimental system at the Hatfield Marine Science Center, which has a large seawater system that makes such research possible.

OSU received a three-year, $2 million grant from the National Science Foundation to lead a seven-institution project to monitor ocean chemistry in the California Current System and look at how two marine species – sea urchins and mussels – respond in the wild to different ocean chemistry.

This month, NSF announced funding for 21 research projects focused on marine organisms’ physiological responses to corrosive ocean water.

Here’s how OSU describes its NSF-funded project:

“Principal investigator Bruce Menge and colleagues from multiple institutions will study urchins and mussels at two sites in Oregon and six sites in California, taking advantage of the differing levels of acidification along the West Coast.

The researchers theorize that these organisms have adapted over time to variations in the ocean chemistry, but the increase in carbon dioxide may be pushing their limit.

“They already may be close to their acclimatization or adaptational capacity,” Menge pointed out, “and thus may have limited ability to respond to additional increases in CO2. For the first time, we will be able to examine the genetics and ecology of these key organisms to see how populations that span over a thousand miles of coastline are coping with changes in ocean chemistry.”

OSU scientists are trying to draw attention to the global problem of increasing ocean acidification. The connection between carbon dioxide in the atmosphere and corrosive ocean waters begs the question of whether oceans need their own climate policy. Previous OSU research, led by Hales, found that seawater now upwelling from deep within the ocean today may have last been exposed to the atmosphere 50 years ago. Its already-high levels of carbon dioxide portend more corrosive oceans in the future.

Ongoing research has also found that the upwelled water is influencing Oregon estuaries, where concern about acidic water has prompted oyster hatcheries to alter their protocols. For example, the Whiskey Creek Hatchery in Tillamook is now drawing water into its tanks during relaxed upwelling periods, or in the afternoon, when acidity levels are lower due to increased photosynthesis.

Northwest climate change Ocean acidification Oregon State University

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