Ocean acidification may be shrinking shellfish, says study

New Scientist : Not only are the oceans growing more acidic due to increasing levels of atmospheric carbon dioxide, but marine life is being forced to adapt or risk extinction. Richard Twitchett of London’s Natural History Museum and colleagues studied two species of sea snail living in the Mediterranean near volcanic seeps, where injections of CO₂ make the water more acidic. They found that the snails living there are about two-thirds the size of those living in water with normal pH. Although the researchers were surprised to find that the smaller snails consumed twice as much oxygen per milligram of tissue as larger snails, their total oxygen consumption was half that of larger snails. That adaptation makes them better able to survive in more acidic environments. The researchers say the dwarfing of marine species due to global warming could have serious consequences for humans who depend on them for food.