Skeletons, shells becoming thinner
A thinning of the protective cases of mussels, oysters, lobsters and crabs is likely to disrupt marine food chains by making the creatures more vulnerable to predators. This could reduce human sources of seafood.
“The results suggest that increased acidity is affecting the size and weight of shells and skeletons, and the trend is widespread across marine species,” the British Antarctic Sur-vey (BAS) said in a statement of the findings.
Human emissions of green-house gases include carbon dioxide from burning fossil fuels, and some of that carbon dioxide ends up in the oceans, where it dissolves to form acid. The ocean acidification makes it harder for creatures to extract calcium carbonate – vital to grow skeletons and shells – especially from chill waters in the Arctic Ocean and around Antarctica, according to the study in the journal Global Change Biology.
“Where it gets colder and the calcium carbonate is harder to get out of the sea water, the animals have thinner skeletons,” Prof. Lloyd Peck of the BAS said.
So a shift toward acidification in the ocean was likely to force animals to have smaller skeletons, he said of the study by scientists in Britain, Australia and Singapore.
“We think that the polar regions, and especially Antarctica, are likely to be the first places where animals reach these critical problems for making skeletons,” he said.
Changes underway in the chill waters were likely to be a sign of what to expect in future in temperate zones and the tropics, he said.
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Vancouver Sun (Jim Drury, Reuters), 8 August 2012. Full article.
Note that the terminology used in this article is misleading. The definition of “acidic” in the Oxford English dictionary is “having the properties of an acid; having a pH of less than 7″. Despite the process of ocean acidification (the acidity of seawater has increased 26% since preindustrial time), the oceans are alkaline (pH higher than 7) and will not become acidic in the foreseeable future. Hence, the words “acid” or “acidic” should not be used when referring to seawater. Note that there are few exceptions, seawater can be acidic in the immediate vicinity of CO2 vents or in purposeful perturbation experiments.