The oceans are turning more acidic. Surface waters absorb carbon dioxide produced by the burning of fossil fuels. And those CO2 molecules react with the seawater to make carbonic acid.
Voilà, a more acidic ocean.
That's big trouble for tiny plants and animals in the sea that make shells. Because more acidic water makes it harder to produce those shells. And once the shells do form, the more acidic water also corrodes the shells. Many marine biologists have thus been anxious that climate change may mean an end to coral reefs.
But a set of experiments undertaken in Hawaii, Moorea and Okinawa give new hope, at least in the Pacific.
Four common corals and algae were subjected to conditions that mimic oceans if CO2 concentrations in the atmosphere reached 1,000 ppm, more than double the levels today. And three out of the four could still easily form their hard calcium shells even in such a more acidic ocean. [Steeve Comeau et al, Pacific-wide contrast highlights resistance of reef calcifiers to ocean acidification, in Proceedings of the Royal Society B]
That doesn't mean ocean acidification won't be bad for corals and algae. But it does mean that across the Pacific some of these organisms can tough it out. Whether other organisms, including us humans, could thrive in a 1,000 ppm CO2 world is another question.
[The above text is a transcript of this podcast.]
[*Clarification (7/31/14): This transcript was edited to reflect a rebroadcast of the original podcast to clarify phrasing and terminology in the original script, which inadvertently created the impression ocean water is acid rather than that it is largely neutral but becoming more acidic.]