Scientists are baffledRising carbon emission from the burning of fossil fuels is increasing the acidity of Earth's oceans. That's very bad for coral reefs, because in acidic environments they can't form calcium carbonate, the building block of their exoskeletons. This, in turn, is very bad because coral reefs are biodiversity hotspots that contain a disproportionally high percentage of the oceans' species relative to their size.
Well, there's at least one exception to every rule, apparently. Scientists have found a coral reef in the western Pacific that is thriving in acidic water conditions. This reef is doing so well in fact that it had higher biodiversity than neighboring reefs despite having a higher level of acidity!
The researchers still haven't figured out why these corals are doing so well in these seemingly inhospitable conditions. They think it could be some unique combination of chemical and biological factors, and this discovery shouldn't be taken to mean that coral reefs will do fine in a more acid ocean. This is a local aberration as far as we know, and we still need to do everything we can to reduce carbon emissions, both to combat climate change and save ocean species that depend on a certain PH level to live.
But still, studying this special coral reef could help us better understand how ocean acidification affects corals and what we can do to help them.
As you can see above, there's a huge difference between a healthy reef and one that has been ravaged by ocean acidification.