Acidification is not your typical household word…yet. Despite not being on the mainstream radar, acidification of our oceans is a serious, and increasing, environmental and economic problem.
Ocean acidification is essentially a water quality problem caused by air pollution. Our oceans are becoming more acidic, caused by the rise of atmospheric carbon dioxide (CO2) in our atmosphere and then the absorption of CO2 by our oceans.
Over the past five decades, human-produced greenhouse gases such as CO2 have increased in our atmosphere exponentially. The increase is largely to blame for global warming, since greenhouse gases trap heat. Oceans absorb nearly 85% of the heat in our atmosphere, which is why water temperatures are warming and sea levels are rising. Twenty-five percent of sea level rise is due to expansion of warming water and 75% is due to added water from the melting of land-based ice.
Not only do oceans absorb heat, they also absorb and neutralize CO2. However, since the industrial revolution we have overwhelmed the oceans’ ability to neutralize carbon. When the oceans are overwhelmed with CO2, an acid-producing chemical reaction begins – this is ocean acidification. Polluting the air with excess CO2 is essentially changing the chemistry of our oceans. It’s often referred to as “the other CO2 problem.”
Like other problems caused by excess CO2 (i.e., climate change effects such as sea level rise, air and water temperatures, storm severity, etc.), ocean acidification and its consequences do not happen uniformly across the globe. Problems associated with ocean acidification are already apparent in New England waters, and will likely have a bigger impact here (as with as in other areas where fishing plays a vital economic and cultural role).
Some regional characteristics can cause acidification to be a bigger problem. One of these characteristics is eutrophication (when excess nitrates and phosphates enter coastal areas from lawn runoff, fertilizers, storm-water runoff, wastewater disposal, etc.). In areas experiencing eutrophication problems, such as along the Cape Cod Bay coastline, there is often die-off of algae and sea grass that produces even more CO2.
Ocean acidification causes a reduction of carbonate in the water. Shellfish need calcium carbonate to form their shells. Obviously this can harm coral, crustaceans, mollusks, and some species of zooplankton. Since these are important members at the bottom of the food web, ocean acidification can also have negative trickle-up effects on other species. For instance, predators – especially feeding specialists – that no longer have their prey available can also struggle to survive.
The impacts of ocean acidification are already being seen in the northeast Atlantic, particularly on shellfish and some zooplankton. Copepods, a type of zooplankton, are showing lower reproductive ability. Copepods are important prey for many species, most notably the north Atlantic right whale – a critically endangered species and one of the rarest large whales in the world. Shellfish – especially clams, scallops, and lobsters – are incredibly important to our economy and ecosystem in the northeast. Ocean acidification has the biggest impacts on these mollusks and crustaceans at their larval stage. For example, larval lobsters are very susceptible. Acidification causes them to grow much slower, develop softer shells, and produce less meat as adults. The acidic conditions also cause the larval life stage for some species to last longer. Since predation of shellfish is the highest during this life stage, it means more are not surviving to adulthood.
Clearly, CCBW is concerned about the potential impacts that ocean acidification could have on the overall health of Cape Cod Bay. It also raises concerns about the dry cask nuclear waste storage facility being built 100 feet from the shore of the Bay, at the Pilgrim nuclear station. The dry casks could be there anywhere from 80 years to indefinitely – scenarios currently being considered by the NRC. Dry casks are made of concrete and steel – materials already susceptible to deterioration by salt air and water. Adding even more acidic conditions raises serious concerns about carbonation-induced deterioration of the dry casks that are intended to protect the public and environment from the highly radioactive waste stored inside.