Acidification Impacts Fish in Surprising Ways.

• Position: OCEAN WARMING

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 CT scans of skate skeletons, Valentina Di Santo, a postdoctoral fellow in the lab of George Lauder, professor of evolutionary biology at Harvard, was able to show that, while ocean acidification has led to a drop in the mineralization of some parts of the skeletons, it has had the opposite effect in other areas.

The study suggests that continued ocean warming and acidification could impact everything from how fish move to how they eat. "This result was very surprising," admits Di Santo. "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.

"I was looking at skate embryos that live off the coast here in New England, and studying the effect of developmental acclimatization to ocean acidification on their physiology and...