Rhode Island is identified in a new study as one of the top at-risk areas from ocean acidification in the nation.

A new study published in the journal Nature Climate Change looks at impacts on shellfish stocks from ocean acidification, identifying Rhode Island waters as one of the top 15 at-risk areas in the nation.

Mark Gibson, deputy chief of marine fisheries at the R.I. Department of Environmental Management, called ocean acidification a “significant threat to local fisheries,” in the Providence Journal. It has been speculated that past reductions of quahog growth rates in Narragansett Bay may have been related to increased acidity.

Nearly one quarter of all carbon emissions produced by transportation and power plants worldwide are absorbed by the oceans. Colder waters, such as those in the North Atlantic, absorb greater amounts of carbon-dioxide from the atmosphere that lowers pH levels. And carbon dioxide from local sources such as lawn care and sewage systems also contributes to increased acidity in Rhode Island coastal waters.

This is bad news for shellfish which rely on aragonite — a common, naturally occurring form of calcium carbonate — in order to produce their shells. Increased acidity means less of the aragonite that shellfish need in order to produce a shell thick enough to protect themselves from predation. With increased pH, clams and other mollusks are forced to expend more energy to build their shells rather than focusing on reproduction and survival, according to the study.

Rhode Island was identified by researchers as an area with high social vulnerability in relation to the well-being of local shellfisheries, whose landings of oysters and clams have been valued at approximately $14 million annually over the last decade. The state’s growing aquaculture industry has also increased the value in farm-raised oysters, averaging $4.2 million over the last five years for the tiniest state in the Union. Although Rhode Island shellfish have yet to face any real impacts from growing acidity, the potential implications highlight the need for more research.

Quahog fishermen collecting wild harvest in Narragansett Bay

Quahog fishermen collecting wild harvest in Narragansett Bay

Gibson says that not much is known about the effects of ocean acidification on marine life in Rhode Island, according to the Providence Journal, but there’s speculation that it may be linked to declining quahog growth rates and lobster shell disease.

One of the key findings of the study released in Nature Climate Change is the existence of key information gaps. These gaps pertain to scientific knowledge of carbon’s behavior in coastal waters, the ability of shellfish to adapt to acidity, and the impact of community dependence on shellfish.

“We lack data on the value chain that links threatened organisms to harvesters, processors and end-users,” the study states.

The next step, according to the study, “is to develop targeted efforts tailored to reducing social and ecological vulnerabilities and addressing local needs.” Solutions to the problems induced by ocean acidification are expected to be locally oriented and include a wide array of tactics, such as diversifying the types of marine species that are harvested.

David Beutel, aquaculture coordinator for the R.I. Coastal Resources Management Council agreed, adding that the “mitigation of acidity needs to begin on a local level.” The greatest steps towards local mitigation would relate to reducing sources of water pollution and identifying strains of mollusks that could be more capable of living with higher acidity.

Currently, state representatives are working to introduce legislation that would create a commission to further study the impacts of acidification in Rhode Island waters. The recent release of the state’s first Shellfish Management Plan also highlighted ocean acidification and the need for increased local research. The reduction of carbon emissions and water pollutants would be essential elements in any strategy to reduce acidity in Narragansett Bay.

 

Evan Ridley | Sea Grant Science Communications Intern and Marine Affairs student at the University of Rhode Island

 

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