Ocean acidification endangers local aquaculture

The rise in ocean acidification is disproportionately affecting marine economies and ecosystems in Massachusetts — particularly those of mollusks, which have a higher mortality rate based on the acidity of the water.

In order to address the rapid rise in ocean acidification over the past several years, the Massachusetts Special Commission on Ocean Acidification Tuesday released a report laying out necessary steps to take in combating this environmental and economic crisis.

The commission consists of 18 members, including state Sen. Julian Cyr, D-Truro, state Rep. Dylan Fernandes, D-Falmouth, along with other lawmakers, gubernatorial appointees, heads of environmental groups, scientists, and local fishermen.

During a press conference, Fernandes said the rise in ocean acidification is an “existential crisis” that disproportionately affects coastal communities in Massachusetts that rely heavily on the blue economy — particularly shellfish aquaculture.

According to the report, the two main ways the state can work to mitigate ocean acidification are by reducing global atmospheric carbon dioxide caused by fossil fuel emissions, and by reducing local nutrient pollution, leading to eutrophication of coastal waters.

The world’s oceans have absorbed as much as 30 percent of the carbon emissions generated by human activity since the beginning of the industrial era, according to the report, and by the year 2100, ocean acidity could increase by 114 percent. 

When the water becomes more acidic, mollusks like oysters, scallops, and other highly valuable and important marine organisms have a tougher time building and strengthening their shells, and can even have shell strength reduced. Crustaceans such as the American lobster are also negatively affected by acidification.

As a result, mollusk mortality rates rise with levels of ocean acidification, as predators can more easily bypass their only defense mechanism. Juvenile oysters can also be dissolved in highly acidic environments.

Additionally, harmful algal blooms, dead zones, and mass dyings in local water bodies begin with the increased load of nutrients (nitrogen) in estuaries and coastal waters. This causes excessive growth in marine plants and algae. When those organisms die, they drastically increase the acidity of the water. In this way, eutrophication and ocean acidification are closely linked. 

Cyr said the large majority of aquaculture on the Cape and Islands takes place in estuaries that are particularly vulnerable to increased nitrogen loading caused by effluent seeps from septic tanks, and by runoff.

According to the report, the shellfishing industry in the U.S. is expected to lose more than $400 million annually by 2100 if ocean acidification goes unabated.

Cyr said at the conference that one of the most important elements of combating ocean acidification is establishing a “broad and sensitive ocean-monitoring system,” which in Massachusetts is currently lacking adequate resources.

And by establishing an ocean acidification council and trust that will work on these initiatives into the future, Cyr said, industry experts and scientists will be leading the charge.

Fernandes stressed the importance of looking at the rise in global temperatures and ocean acidification as interrelated issues, and noted that any future monitoring should take those dual impacts into account.

Emily Lockhart, deputy general counsel and director of regional initiatives for the Woods Hole Oceanographic Institution, said there are some fragmented monitoring programs coming from the local, state, and federal governments, but they aren’t collaborating effectively to create a broad network of support. “We can’t manage what we can’t monitor,” she said.

Fernandes noted that with better real-time data monitoring, members of the aquaculture industry would be able to adjust and adapt with newfound data, and make informed decisions on where to farm, and what methods to use.

Coastal economies in Massachusetts rely heavily on the aquaculture industry, and with the current housing crisis and a high cost of living, Cyr said, those types of jobs are especially important to preserve.

“Aquaculture has been one of the few bright spots when we look at coastal communities. People can make a good life here in this industry,” Cyr said.

Seth Garfield, owner of Cuttyhunk Shellfish, Inc., said he is concerned with shellfish hatcheries and their ability to produce seed for the hundreds of commercial shellfishermen across the commonwealth.

He said if that critical period that produces juvenile shellfish is disrupted or delayed, hundreds of aquaculturists who rely on those hatcheries will experience a potentially disastrous delay in their production.

Although a large portion of preventive measures must take place at the local level with increased coastal wetlands protections and restoration efforts, bylaws that limit nitrogen loading and fertilizer runoff, and others, Fernandes said, the state is working hard to reduce carbon emissions and mitigate ocean acidification.

The Cape and Islands Water Protection Fund was created in 2018, and is funded through a 2.75 percent excise tax on room occupancy for traditional lodging and short-term rentals. 

For municipalities that opt in, this fund will provide resources that allow better management of wastewater, and address the growing problem of eutrophication in local water bodies.

Steve Kirk, coastal programs manager for the Nature Conservancy, suggested nature-based solutions for managing stormwater flow, and protecting wetlands and shoreline that absorb excess nutrients. “These problems are stemming from the way we live on the land,” Kirk said.

Lockhart added that there are things people can do on the individual level to reduce eutrophication and ocean acidification, such as conserving water, watching what you pour down the drain, and not putting nitrogen-based fertilizers on your lawn.

She stressed that any environmentally conscious efforts that individuals can adopt at home will benefit our oceans and estuaries.