A short animation about the potential impact of ocean acidification on sea life in the Gulf of Maine. Produced with support from Maine Sea Grant, Dalhousie University, MEOPAR (Marine Environmental Observation Prediction and Response Network), NERACOOS (The Northeastern Regional Association of Coastal Ocean Observing Systems) and NECAN (Northeast Coastal Acidification Network).
By Ramona du Houx
The Maine Legislature is still considering a bond proposal aimed at addressing ocean acidification (OA) in the Gulf of Maine. LD 998, sponsored by Rep. Wayne Parry (R-Arundel) and Rep. Mick Devin (D-Newcastle), would ask voters to approve a bond to borrow $3 million to be used to collect data, monitor waterways and test ocean acidity along the Maine coast and study its impact on wildlife and commercial shellfish species.
“Maine faces a tremendous, fast-evolving environmental challenge,” said Sebastian Belle, executive director of the Maine Aquaculture Association and member of FocusMaine, in testimony last June. “The implications of ocean acidification are only beginning to be understood, but one thing is clear, unless we have the tools to accurately monitor ocean acidification trends, we will be unable to react in terms of management and policy decisions.”
There is virtual consensus among scientists that about a quarter of the carbon dioxide emitted from fossil fuels and deforestation ends up in the oceans. “There is no argument about this. This is really simple high school chemistry,” said University of New Hampshire OA expert Joe Salisbury.
As the C02 gets absorbed into the ocean it reacts with seawater to form corrosive carbonic acid, which reduces the alkalinity of the water and inhibits the formation of the molecule calcium carbonate. Maine's hallmark shellfish like clams, lobsters, mussels, shrimp, scallops, oysters and sea urchins use calcium carbonate as the building blocks to form their shells. With fewer calcium carbonate molecules, they have to spend more energy for shell production, which hinders their ability to grow. If the water gets too acidic, it can even dissolve shells.
This could devastate Maine's shellfish industry which is a huge part of the state's tourism industry.
Under ordinary circumstances, the ocean can naturally buffer excess C02. But ever since the Industrial Revolution, humans have emitted so much carbon dioxide into the air and water that chemical changes are happening much faster than at any time during the past 200,000 years.
The Gulf of Maine's uniqueness also unveils it's inherent weakness to the effects of rapid OA.
"The northwestern Atlantic, where we live, is particularly sensitive to OA, and it could change really quickly based on water mass changes and we really need to know a lot more,” said Salisbury.The Gulf of Maine is particularly susceptible to acidification because it receives so much fresh water from the region’s many large rivers, as well as cold, fresh water from the Gulf of St. Lawrence, and snow and ice melt from the Arctic via the Labrador Current. While the region’s complex flow of water delivers some of the best shell fish on the planet the flow also compounds the acidifying effect because carbon dioxide is more soluble in cold water and fresh water has lower concentrations of carbonate and calcium ions.
If the saturation state of calcium carbonate, which is typically 2-5 in the global ocean, goes below 1.6, it can have a detrimental effect on shellfish, especially during their larval stages.
“Hatcheries are definitely the canaries in the coal mine,” said Bill Mook, who owns Mook Sea Farm in Walpole. “The window of conditions that are going to be sufficient for natural bivalve larvae is going to continue to close and you’re going to see less predictable recruitment. And that’s what you’re seeing in a lot of places.”
Mook hopes Maine law makers will be able to take a proactive approach to the problem and look at how OA impacts the entire Gulf of Maine ecosystem rather than just individual species.
“We need to demand that the government spends more money in establishing monitoring systems and doing the thoughtful, correct research that’s going to provide businesses like mine with enough information so that we can do a little more planning and come up with strategies to cope with all of this. We can’t avert crises if we don’t know about them and information is really key to our survival.”