Carbon dioxide (CO2) emissions not only lead to global warming, but also cause another, less well-known but equally disconcerting environmental change: ocean acidification. A group of 35 researchers of the EU-funded EPOCA project have just started the first major CO2 perturbation experiment in the Arctic Ocean. Their goal is to determine the response of Arctic marine life to the rapid change in ocean chemistry.
Ocean acidity has increased by 30% since preindustrial times due to the uptake of anthropogenic CO2. It is projected to rise by another 100% before 2100 if CO2 emissions continue at current rates. Polar seas are considered particularly vulnerable to ocean acidification because the high solubility of CO2 in cold waters results in naturally low carbonate saturation states. CO2 induced acidification will easily render these waters sub-saturated, where seawater becomes corrosive for calcareous organisms. By the time atmospheric CO2 exceeds 490 parts per million (2040 to 2050, depending on the scenario considered), more than half of the Arctic Ocean is projected to be corrosive to aragonite. Arctic waters are home to a wide range of calcifying organisms, both in benthic and pelagic habitats, including shell fish, seas urchins, coralline algae, and calcareous plankton. Many of these are key species providing crucial links in the Arctic food web, such as the planktonic pteropods, which serve as food for fishes, seabirds and whales.
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AlphaGalileo, 3 June 2010. Full article.
