Imagine savoring a seafood feast on a perfect Maine summer day—maybe a basket of fried clams, oysters on the half-shell, or a fresh lobster roll. Now imagine a future where these delicious food traditions are at risk because Maine’s shellfish struggle to survive in acidifying waters. This is the challenge a group of Maine scientists are working to tackle: ocean acidification.
On December 10, the Maine Ocean Climate Collaborative (MOCC) hosted a Symposium on Ocean Acidification in Rockland. More than 50 scientists and policy experts from organizations such as Bigelow Laboratory, Island Institute, Maine Department of Environmental Protection, and Maine Department of Marine Resources, shared strategies to address ocean acidification. Casco Baykeeper Ivy Frignoca, a coordinating member of MOCC, was heavily involved in organizing this important gathering of experts from across the state.
The Maine Ocean Climate Collaborative (MOCC) includes: Bigelow Laboratory for Ocean Sciences, Bowdoin College, Casco Bay Estuary Partnership, Downeast Institute, Friends of Casco Bay, Governor’s Office on Policy Innovation and the Future, Hurricane Island Center, Island Institute, Maine Center for Coastal Fisheries, Maine Coastal Observing Alliance, Maine Department of Environmental Protection, Maine Department of Marine Resources, and Wells National Estuarine Research Reserve.
What’s acidification? Why is it a problem?
The ocean acts like a giant sponge, soaking up 30% of global carbon emissions. While this reduces the load on the climate, it triggers chemical reactions that increase ocean acidity and reduce calcium carbonate—a critical building block for shellfish. “The more acidic it gets, the more some species are going to struggle,” explains Staff Scientist Mike Doan.
Shellfish like clams, oysters, scallops, mussels, and lobsters, depend on calcium carbonate to grow their shells. Without it, they struggle to mature and fight off disease. According to a June 2024 Maine Climate Council report, by 2050, Gulf of Maine waters could be too acidic for shellfish to thrive. That’s not just bad news for the clams—that’s bad news for Maine’s $600 billion+ fishing industry.
A Data Dilemma
Most ocean acidification data comes from offshore waters, far from Maine’s clam flats and oyster farms. However, offshore data doesn’t capture the dynamic conditions of nearshore waters, where tides and runoff create a constantly shifting environment. Land-based carbon and nitrogen sources can further exacerbate nearshore acidity. Maine needs consistent, accurate data to understand and address these localized challenges.
Collecting such data, however, has long been a challenge. High-quality monitoring tools are often prohibitively expensive and require significant upkeep, putting them out of reach for many coastal conservation groups and agencies. Cheaper alternatives, while less costly, are less accurate and limited to surface-level measurements. This is where the Sensor Squad of the MOCC—a team of researchers formed in 2023—stepped in.
The Sensor Squad Seeks Affordable Solutions
At the Symposium, the three-member Sensor Squad—Mike Doan, Jeremy Miller of Wells National Estuarine Research Reserve, and Dr. Chris Hunt of the University of New Hampshire—shared the results of their two-year study to identify affordable and reliable tools for monitoring nearshore ocean acidification.
The Sensor Squad honed in on glass-electrode tools as a middle ground for reliability and affordability. After testing various models in the lab and field, they developed best practices for using data sondes—versatile instruments with probes that can measure water health at different depths. These tools are relatively easy to calibrate and maintain. Data sondes empower organizations such as Friends of Casco Bay to monitor local waters more effectively.
To deepen their analysis, the team combined sonde measurements of pH with bottle samples analyzed for total alkalinity. Together, these data points provide a clearer picture of acidification’s effects. The Sensor Squad’s findings represent a big step forward, but they emphasized that continued research and collaboration are needed to help shellfish farms, wild harvesters, and aquaculture businesses adapt to changing conditions.
Seaweed: A Kelp-ful Solution
While the Symposium revealed the challenges of ocean acidification, it also showcased innovative solutions. One promising approach involves seaweed aquaculture. Dr. Nichole Price of Bigelow Laboratory presented her research on growing kelp alongside mussels in Casco Bay. Kelp absorbs carbon dioxide, creating “halos” of improved water conditions that reduce acidity and boost oxygen levels. This method not only supports marine life but also provides new opportunities for aquaculture farmers.
Collaboration Is Key to Tackling Acidification
The Symposium highlighted the power of collaboration in addressing ocean acidification. MOCC members emphasized the need for monitoring efforts to inform actionable policies that protect Maine’s coastal ecosystems.
Mike Doan’s work designing Friends of Casco Bay’s Continuous Monitoring Stations has helped our organization better understand ocean acidification within the broader context of water quality changes affecting our coastal waters. This science-driven approach, combined with collaboration across the state, helps us continue to protect Maine’s shellfish and the coastal communities that depend on them.
Together, we’re working toward a future where enjoying a seafood feast—from Maine’s iconic working waterfront—remains a cherished tradition for generations to come.
