How Does Ocean Acidification
Imperil Sea Life?

Ocean acidification prevents varieties of sea life from building shells, including crab, oysters, lobsters, mussels, clams, urchins, plankton and corals. Acidification occurs when carbon dioxide (CO2) levels in the atmosphere are absorbed by seawater, creating carbonic acid (H2CO3). The acid breaks down solids and bonds with other molecules, increasing the water’s acidity. Fossil fuel emissions are primarily responsible for excess atmospheric CO2.

Approximately one quarter of the man-made gases in the atmosphere are absorbed by oceans. Carbon emissions increased from 2 billion tons/year in 1950 to 9 billion tons/year today. Scientists are skeptical about how much more CO2 the oceans can absorb. Dungeness crab shells, made of chitin (similar to cellulose), not calcium carbonate (oysters), are affected by this change in the water chemistry that shifts their metabolism.

Organisms must spend too much time and energy building their shells. Studies on sea urchins and mollusks reveal their shells dissolve in acidic water in 30 days. Washington State’s Puget Sound oyster farmers, have found that their oyster “babies” were unable to “properly form calcium carbonate shells as the pH drops.”

The Dungeness crab industry, economically critical to California and the Pacific Northwest, is worth nearly $250million dollars annually. This industry could be seriously affected by increasing “greenhouse gas pollutio (hurting) the survivability of crab larvae,” reported scientists at the Northwest Fisheries Science Center(NFSC) in Seattle. Accordingto NOAA fisheries, the total value of the 2014 Dungeness crab catch in Alaska, California, Oregon and Washington was $211.5 million. ““Even though [Dungeness crab are] incredibly tough, they are also susceptible to environmental conditions.” said Paul McElhany, a NFCS research ecologist. His next research project is studying how feeding on crab larvae impacts salmon. For more information, see this 17 May Seattle Times article, and this video on acidification from NOAA’s Pacific Marine Environmental Laboratory.