As the oceans become more acidic, threat to sealife and industry grows, new study finds

The ocean’s growing acidity, which goes hand in hand with climate change and other human-driven factors, could have a devastating effect on the state’s coastal waters and the shellfish industries that rely on their ecosystems, according to a new report.

The study, written by a group of state legislators, scientists, conservationists, and representatives of the commercial fishing industry, estimated that if current trends continue, the US shellfish industry could lose more than $400 million a year by the end of the century.

“Our coastal waters are incredibly valuable, and they’re under increasing stress,” said Steve Kirk, coastal program manager for The Nature Conservancy in Massachusetts and a member of the commission. “I’m hopeful that if we address ocean acidification now, we will give those coastal communities a better chance of thriving in the future.”

Oceans can become more acidic as they absorb carbon dioxide that is released into the atmosphere. Another major factor is nutrient runoff — wastewater, fertilizer, and other materials that make their way to the ocean and feed algae blooms that create a vicious cycle. Those blooms soak up large amounts of oxygen in their environment, depriving other organisms of it. As a result, those organisms can suffocate and die, producing more carbon dioxide as they decompose and making the water around them more acidic.

Changing the way wastewater is treated to remove some of those nutrients, like nitrogen, could make a big difference, Kirk said.

“We understand those processes and we know how to address them,” Kirk said. “So I’m looking forward to those recommendations being taken up and addressing those challenges.”

While some species, like algae and some sea grasses, adapt better to more acidic waters, certain mollusks, like eastern oysters, sea scallops, and Atlantic surf clams, become more vulnerable. The acidity and higher bicarbonate levels — a byproduct of increased carbon dioxide levels in the ocean — interfere with how the mollusks form their protective shells.

Those added stressors mean fewer mollusks live past the larval stage of their lives, and those that do are typically smaller. And if mollusks are vulnerable, so are the fishing economies that depend on them.

The commission was created by the Legislature to determine how acidification along the coasts might affect the environment and ocean industries.

“If left unaddressed, our state’s $688 million-dollar fishing industry will face unprecedented disruption and our blue economy will suffer,” state Representative Dylan Fernandes, a Falmouth Democrat, said in a statement.

Lobsters and crabs, both critical industries in New England, appear slightly more resilient to acidification. But some researchers believe exposure to acidic environments might make spider crabs less able to thrive in warmer waters, another danger they face in a changing climate. Not enough research has been done on how the animals fare with the dual effects of warming and acidification.

But quick action can help mitigate some of those consequences, the report said. That includes more comprehensive studies of the impacts of acidification and temperature changes on shellfish species that keep the fishing industry afloat and organized efforts to limit nutrient runoff.

“If we work together, there are innovative solutions that we can implement, such as repurposing waste shells to improve the growth and vitality of shellfish in the wild,” said Kelly Kryc, director of ocean policy at the New England Aquarium. “That’s the wonder of science.”

Gal Tziperman Lotan is a former Globe staff member.