Geology 37, 1131–1134 (2009).

Credit: © ISTOCKPHOTO / SHARON METSON

The lobster is one creature that could fare better in an acidic ocean. Experimental evidence has shown that the sea's shelled inhabitants, and those with exoskeletons, could struggle to survive as CO2 continues to invade the ocean. But in fact there will be winners and losers, finds a new study.

Justin Ries of the University of North Carolina at Chapel Hill and colleagues reared 18 species of 'marine calcifiers' for 60 days in experimental seawater tanks that had uniform temperature but varied in acidity and in the availability of the carbonate ion used by calcifiers to build their shells and skeletons. Ries and colleagues found that 10 of the 18 species were less able to build their encasings in acidic seawater than in regular seawater. For four of the species tested — limpets, purple urchins, and red and green algae — the ability to calcify improved in waters of intermediate acidity but worsened in highly acidic waters. Lobsters, crabs and shrimp, however, were unexpectedly able to build more shell as the acidity of the seawater increased.

The results suggest that the impacts of ocean acidification on marine life may be more complex than previously thought.