For more than a century, the world’s oceans have been becoming steadily more acidic as they soak up ever-increasing amounts of carbon dioxide from the atmosphere, and the impacts can be fatal for invertebrates such as shellfish, plankton, and corals that rely on dissolved minerals to build their shells and exoskeletons.
For at least some fish, though, the story may be more complicated.
Using precise CT scans of skate skeletons, Valentina Di Santo, a postdoctoral fellow in the lab of Evolutionary Biology Professor George Lauder, was able to show that, while ocean acidification has had led to a drop in the mineralization of some parts of the skeletons, it has had the opposite effect in other areas. The first-of-its-kind study suggests that continued ocean warming and acidification could impact everything from how fish move to how they eat. The findings are described in a Jan. 9 paper published in the Proceedings of the Royal Society B.
“This result was very surprising,” Di Santo said. “Until now, most research had been focused on the mineralization of the exoskeletons of invertebrates, because we know they experience very dramatic impacts from acidification, but nobody had looked at what happens to vertebrates.”
One reason for the lack of such studies, she said, is simply physiological: Unlike shellfish or coral, fish have internal skeletons.
“For the most part, people thought fish would be pretty resilient,” she said. “Certainly acidification stresses them — their metabolic rates go up and studies have shown behavior changes — but they have managed to adjust. But the more we investigate, the more we see that there are strong negative effects, even in the skeleton.”
Though she ended up finding it, Di Santo wasn’t searching for evidence of how acidification was impacting fish skeletons.
