Global warming

According to Steneck and his colleagues, as the Earth’s atmosphere grows warmer and the concentration of carbon dioxide (CO2) continues its increase, global sea temperatures will also rise, and the oceans will become more acidic.

Like coral reefs, lobsters (and bivalves such as clams) depend on drawing calcium carbonate from the water to build their shells. In theory, if the waters of the northeast Atlantic ocean grow more acidic, crustaceans and bivalves will have to work harder to build their shells and will have less energy available to forage for food, but scientists are unsure of how lobsters in the Gulf of Maine would be affected.


Lobsters precipitate calcium out of the ocean through their blood system. To predict what impact acidification might have on the lobster population over the next 50 to 100 years, Incze said, it is necessary to have “some idea of how much ocean acidity will increase” during that period.

Lobsters are cold-blooded, their body temperatures determined by the water in which they live. Higher temperatures cause cold-blooded animals to use more energy for respiration, leaving less energy for feeding, growth, energy storage, immune response and reproduction. Much of a lobster's life is related to the temperature on the ocean floor — what it eats, how successfully it breeds, where it migrates.





As ocean temperatures fluctuate, so do the lobsters' habits. Lobsters can respond to temperature changes by changing their habitat. For example, lobsters are likely to move toward higher latitudes or to areas cooled by tidal mixing. In New England, for example, such populations will move north toward the Bay of Fundy.

Warming temperatures increase the lobster’s respiration rate and oxygen needs while reducing the amount of dissolved oxygen available. Research has found that as water temperatures rise above 69 degrees F, lobsters' respiration rate increases to a point where their demand for oxygen exceeds the supply, causing physiological stress.