Ocean acidification caused by climate change is making it harder for creatures such as clams and sea urchins to grow their shells, and the trend is likely to be felt most in the polar regions, scientists said yesterday.
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, which 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 Survey (BAS) said in a statement of the findings, which were published in the journal Global Change Biology.
Human emissions of greenhouse gases include carbon dioxide from burning fossil fuels. Some of that carbon dioxide ends up in the oceans, where it dissolves to form acid.
The acidification makes it harder for creatures to extract calcium carbonate – vital to grow skeletons and shells – especially from cold waters in the Arctic Ocean and around the Antarctica, said the study by scientists in Britain, Australia and Singapore.
Changes under way in cold waters could be a sign of what to expect in future in temperate zones and the tropics, said the BAS.
The experts studied four types of creatures – clams, sea snails, lamp shells and sea urchins – at 12 sites, stretching across the globe, from the Arctic to the Antarctic.
“The fact the same effect occurs consistently in all four types suggests the effect is widespread across marine species, and that increasing ocean acidification will progressively reduce the availability of calcium carbonate,” it said.
In the past, animals had evolved to be able to live in places where calcium carbonate is relatively difficult to obtain – such as in the Antarctica – by forming lighter skeletons, it said.
So there was hope that they might be able to evolve again to adapt.
“Given enough time and a slow enough rate of change, evolution may again help these animals survive in our acidifying oceans,” said Dr Sue-Ann Watson, a Research Associate at James Cook University in Australia.
2012 MediaCorp Press Ltd.