© D. Gordon E. Robertson, Wikimedia Commons
A species of starfish has confounded climate change doom-mongers by thriving as sea temperatures and acidity increase - a scenario that is likely as the world gets warmer.

Most studies have concluded that sea animals with calcified shells or skeletons, such as starfish, will suffer as carbon dioxide from burning fossil fuels dissolves in the sea, making the water more acidic and destroying the calcium carbonate on which the creatures depend.

But the sea star Pisaster ochraceus may ride out the climate storm. Rebecca Gooding and colleagues at the University of British Columbia in Vancouver, Canada, exposed sea stars to rising temperatures and water acidity. They thrived in temperatures of up to 21 °C and atmospheric CO2 concentrations of up to 780 parts per million - beyond predicted rises for the next century (Proceedings of the National Academy of Sciences, DOI: link).

The sea star seems to survive because its calcium is nodular, so unlike species with continuous shells or skeletons it can compensate for a lack of carbonate by growing more fleshy tissue instead. The team therefore warn against assuming that global warming will have the same impact across groups of similar species.