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is unknown shell-making requires energy and that energy could be diverted from other life functions such as growth and reproduction.3 Zooming in to the local level While atmospheric CO2 increases at an even rate across the world increasing ocean acidity is not globally uni- form. Many marine scientists dierentiate ocean acidi- cation from coastal acidication because the way inshore waters become more acidic goes beyond atmospheric deposition. Due to its cold fresher nutrient rich waters the Gulf of Maine is considered to be an ocean acidication hotspot. A study led by Woods Hole Oceanographic Institute found that the Gulf of Maine has the lowest acid buering capacity4 of any region on the eastern seaboard. Cold water can absorb more gas than warm water. So cold water absorbs more CO2 which makes colder water more acidic. Moreover Maines 60 freshwater rivers makes the inshore waters more acidic because freshwa- ter is naturally more acidic. In Maines more populated areas like Casco Bay high nutrient run o from fertilizer and waste water treatment plants as well as deposition of airborne pollutants exacerbates local acidity in semi- enclosed bays by triggering algal blooms which decrease oxygen and further increases CO2. Although Maine is often idealized as a pristine area the coastal ecosystem and the people who depend on it are vulnerable due to the natural and human induced reasons stated above. Maines real risk does not come directly from its cold acidic water but from the regions economic reliance on the very species that are projected to be aected by it. The Gulf of Maine once supported a diverse ecosystem but now as a result of overharvesting of sh stocks it is crustacean dominated. The lobster industry in Maine has been booming in the last decade and is home to the highest lobster density in the world. In 2013 78 368 million of all sheries revenue in Maine came from lob- stering. See Figure 2. The Downeast Fisheries Partnership DFP which Manomet formed in 2012 with the Penobscot East Resource Center and the Downeast Salmon Federation is trying to restore diversity to the Downeast Maine aquatic ecosystem so that communities will be able to sh for- ever. Dependence on a single shell-bearing specieslob- sterin the face of warming waters and acidifying waters presents a risky and vulnerable future for rural coastal communities. Our approach to locally driven management will help Maines sheries to adapt to a series of threats including acidication said DFP Coordinator Anne Hayden. Local stakeholders have the most intimate knowledge of how their ecosystems are aected by coastal acidity. Rebuilding diversity in river and coastal ecosystems and engaging shermen and others in their stewardship will make rural communities more resilient to unforeseen changes. Ocean acidication is already disrupting some Maine ecosystems. Maine clammers have noticed that ats which were once productive are no longer economically harvestable. A study by Friends of Casco Bay found that in a comparison of productive and unproductive ats nearly all unproductive ats in the Casco Bay had mud with low pH while all productive ats had higher pH5. We know from research that acidic mud negatively aects clams and we know that we have low pH mud in our coastal ats explained Casco Baykeeper Joe Payne. However its hard for us to talk about this issue when clammers are faced with problems that they can see like invasive green crabs Carcinus maenas. There are a lot of ats that are no longer productive but if coastal acidica- tion is the lead culprit this is something we can manage. Luckily for Maine ocials have begun to take action to address this issue. In May the State Legislature formed the groundbreaking Maine Ocean Acidication Study Commission to assess the threat of ocean acidication on the States commercially harvestable species. The Commission the rst of its kind on the east coast will American Lobster American Eel Atlantic Herring Pollock Bloodworms Softshell Clam Eastern Oyster Sea Scallop Sea Urchin Everything Else American Lobster American Eel Atlantic Herring Pollock Bloodworms Softshell Clam Eastern Oyster Sea Scallop Sea Urchin Everything Else Figure 2. NOAAs 2013 Annual Commercial Landing Statistics show lobsters contributed 78 of Maines 475 million dollar fishing revenue while 89 of the fishing economy came from shellfish. This huge reliance on shell building organisms makes the potential effects of ocean acidification important to Maine. 3 Ries J.B. Marine calcifiers exhibit mixed responses to CO2-induced ocean acidification. Geology. 1131-1134 pp. Available online httpintl-geology.geoscienceworld.orgcontent37121131.full.pdfhtml 4 Gulf of Maine has the lowest alkalinity to dissolved inorganic carbon ratio of any region on the eastern seaboard. Wang Z.A. 2013. The marine inorganic carbon system along the Gulf of Mexico and Atlantic coasts of the United States Insights from a transregional coastal carbon study. Limnology and Oceanography. 325-342 pp. Available online httpwww.aslo.orglotocvol_58issue_10325.pdf 5 Friends of Casco Bay. 2013. The Mystery of the Disappearing Clams. Available online httpwww.cascobay.orgthe-mystery-of-the-disappearing-clams Breakdown of Maines Fishing Economy 2013 9