Cold water absorbs more CO2, so it is around the Poles that the consequences of ocean acidification are first felt. Pteropods – tiny swimming Arctic sea snails – have difficulty building their shells at CO2 levels very close to the present ones. They are staple diet for juvenile salmon. Ocean acidification is a genuine threat to ecology. And ’10 percent less pteropods means 20 percent less salmon’.
Yesterday the Geological Society of America met in Denver. “Models are probably underestimating at least by a few years the impact of ocean acidification in the Arctic,” say the researchers.
Chemical oceanographer Jeremy Mathis says measurements show the acidification to be several years ahead of predictions in northern waters (both the Chukchi and Bering Seas – on both sides of the Strait). Alaska’s king crab and salmon fisheries could be affected – as could the entire ecosystem, abundant as it has been for ages.
Problem is the abundance of minerals in the water that crustaceans, plankton and shellfish use to form their skeletons and shells. Especially aragonite is important – a readily available form of calcium carbonate. With increasing CO2 levels however, the aragonite dissolves.
A recent study in Biogeosciences predicts a seasonal aragonite under-saturation in Arctic waters from around 2016. (The same study states saturation levels needed for coral growth would vanish by 2070.) Mathis’ research in the Gulf of Alaska uncovered multiple sites where the aragonite concentrations were already as low. Shellfish and other organisms in the region are unable to build strong shells.
© Rolf Schuttenhelm | www.bitsofscience.org