New Study: Ocean Acidification Threatens Coastal Communities in 15 U.S. States

Feb 23, 2015

Anticipated Economic Impacts More Widespread than Previously Believed

Annapolis, Md (February 23, 2015) – The first nationwide vulnerability assessment for ocean acidification shows that coastal communities that depend on the nation’s approximately $1 billion shelled mollusk (e.g., oysters and clams) industry are at long-term economic risk from ocean acidification. The assessment illustrates that vulnerable communities are not confined to the Pacific Northwest, which has been the primary focal point of attention and resources. Newly-identified communities at risk reside everywhere from Maine to the Chesapeake Bay to the Louisiana bayou.

The corresponding paper, “Vulnerability and adaptation of US shellfisheries to ocean acidification,” was published today in Nature Climate Change.

“Ocean acidification has already cost the oyster industry in the Pacific Northwest nearly $110 million and jeopardized about 3,200 jobs,” said Julie Ekstrom, Director of the Climate Adaptation Program at the University of California Davis Policy Institute and lead author of the research. “Our research shows, for the first time, that many communities around the U.S. face similar risks.”

Ocean acidification is the result of oceans absorbing the growing amounts of carbon dioxide produced by burning fossil fuels. Acidifying waters make it more difficult for creatures with calcium carbonate shells or skeletons—including mollusks, crabs, and corals—to grow their shells and survive. Mollusks are generally known to be particularly sensitive to ocean acidification and are also among the most lucrative and sustainable fisheries in the United States.

The study, co-authored by scientists supported under a National Socio-Environmental Synthesis Center (SESYNC) research award, integrated physical, economic, and social data into an assessment of various regions’ overall vulnerability to ocean acidification. The risk factors for impacts are numerous. Physical risks that can amplify acidification include nutrient pollution from agricultural runoff. Economic factors, such as total revenues, can influence the importance of shellfish to a community. And social factors, such as the diversity of local employment, decrease communities’ capacity to cope with change. 

“Our analysis shows acidification will harm more than ocean creatures; it will have real impacts on people’s lives,” said Lisa Suatoni, NRDC Oceans Program Senior Scientist. “It will pinch pocketbooks, it will put livelihoods at risk, and it will alter the fabric of communities all across the country.”

The study found different regions face varying combinations of risk factors, making them unique "hot zones" on the map. 

Examples include:

  • Mid-Atlantic hot zones: East coast estuaries such as the Chesapeake Bay, Narragansett Bay, and Long Island Sound, where an abundance of nitrogen pollution exacerbates ocean acidification in shellfish-rich areas.
  • New England hot zones: The productive ports of Downeast Maine and southern Massachusetts, where poorly buffered rivers run into the cold New England waters, which are especially enriched in ‘acidifying’ carbon dioxide.
  • Gulf of Mexico hot zones: Terrebonne and Plaquemines Parishes of Louisiana—and other communities in the Gulf of Mexico—where the shelled mollusk industry is limited to oysters, giving this region fewer options for alternative, potentially more resilient, mollusk fisheries in the short term.
  • Pacific Northwest hot zones: The Oregon and Washington coasts and estuaries, where a potent combination of risk factors converge, including cold waters, upwelling currents that brings corrosive waters closer to the surface, corrosive rivers, and nutrient pollution from land runoff.

Of particular concern are the study’s findings that many of the most economically-dependent regions are currently the least prepared to respond. States such as Massachusetts, New Jersey, Virginia, and Louisiana have minimal research and monitoring for ocean acidification and little government support to reduce their risk (at federal or state levels). Since this assessment focused on mollusks, it offers one slice of overall vulnerability within the ecosystem. The method of analysis in this study should also be applied to a broader set of at-risk species, such and crabs and coral, and the services they provide. 

While reducing global carbon emissions is the ultimate solution, study findings point to localized solutions that can be implemented, including: reduction of local pollutants such as agricultural runoff in the Chesapeake, diversification of fishing fleets and investment in aquaculture of high-value shellfish species in southern Massachusetts (raising shellfish away from souring waters), development of ‘early warning’ systems for corrosive waters in the Pacific Northwest, and the cultivation of acidification-resistant strains of oysters in the Gulf of Mexico.

“There is plenty we can do to help these at-risk communities while protecting our environment,” said Lisa Suatoni. “Tailored action plans should be developed for each ocean acidification hot zone. The time to act is now.”

This research was supported by the National Socio-Environmental Synthesis Center (SESYNC) under funding received from the National Science Foundation (NSF) DBI-1052875.

Additional Information

Media Contacts

Melissa Andreychek, SESYNC
(410) 919-4990

Christine Keeves, NRDC
(415) 875-6155


The National Socio-Environmental Synthesis Center, funded through an award to the University of Maryland from the National Science Foundation, is a research center dedicated to accelerating scientific discovery at the interface of human and ecological systems. Visit us at and follow us on Twitter @SESYNC.

Top photo courtesy Walwyn via Flickr/Creative Commons

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