Ocean acidity rising at its fastest for 300 million years

Global Warming's less well known evil twin, ocean acidification, has caused rising alarm over the last few years.|

Carbon dioxide is soluable in water and the sea is one of the earth's main "carbon sinks". Unfortunately when CO2 dissolves it creates a mild acid - it's the reason why even fizzy water is bad for your teeth - and anything else made of calcium carbonate - including most shellfish, corals, and the skeletons of some planktons.|

A number of papers have confirmed rapid rises in the acidity of the world's oceans. Now, in a new study, reported in Science Daily,  a review of hundreds of paleoceanographic studies, a team of researchers from five countries found evidence for only one period in the last 300 million years when the oceans changed even remotely as fast as today: the Paleocene-Eocene Thermal Maximum. The result - the extinction of almost half the species of a group of single celled formaniferia. It's believed organisms like these lie at the base of marine food change and their loss would have serious effect on the population of larger marine species.

Scientists trying to analyse the impacts of rising acidity have shown that lowered Ph has adverse effects on species ranging from reef and shell building species to the small snails favoured by young salmon. Last year a study of coral reefs in Papua New Guinea found that when Ph dropped to 7.8 reef diversity fell by up to 40%

image Tim Bastable