A new study in the prestigious journal Science Advances shows that stress from rising water temperatures reduces ability of corals to adapt to ocean acidification.
About a quarter of the carbon emissions driving global warming are absorbed by the oceans, leading to lower pH values in the water and making it more acidic. Global warming is also causing water temperature in the oceans to rise, which leads to the bleaching of coral reefs worldwide. Now, a new study reveals that increased CO2 levels in the water and ocean warming can interact to threaten reef-building corals.
The international team of authors, led by the University of California, included researchers from the Alfred Wegener Institute (AWI), Helmholtz Centre for Polar and Marine Research, from the Leibniz Centre for Tropical Marine Research (ZMT) and the Max Planck Institute for Marine Microbiology.
Acidification and warming are a one-two punch that affects corals' ability to form and grow calcium carbonate skeletons. The new study shows how these two factors interact to harm corals more than the sum of their effects would suggest. The rising temperatures appeared to affect the coral's ability to regulate its internal acidity making it more vulnerable to the effects of ocean acidification.
However, corals have also shown the ability to adapt to changing conditions to some extent. But this adaptation may come too late to save the world's major reef systems. Therefore, there is an urgent need to understand the interactions among stressors. Only then can ways be found to successfully protect corals.