Some shark species may adapt to climate change: study

Some shark species may be able to cope with the rising temperature and the subsequent decrease of water salinity, a new study has found.

The study of sharks that lived in warm Arctic waters millions of years ago suggests that some shark species could handle the falling Arctic salinity that may come with rising temperatures.

No one knows exactly what effect climate change could have on various species; scientists believe some species will be at risk, though others might thrive.

According to study leader Sora Kim, from the University of Chicago, past climate change in the Arctic can serve as a proxy to better understand our current climate change and aid future predictions.

The Eocene epoch, she said, is like a “deep-time analogue for what’s going to happen if we don’t curb CO2 emissions today, and potentially what a runaway greenhouse effect looks like.”

Kim and Jaelyn Eberle from the University of Colorado, studied shark teeth from a coastal site on Banks Island. This allowed them to better understand the changes in ocean water salinity across a broader geographic area during a time of elevated global temperatures.

Kim isolated and measured the mass ratio of oxygen isotopes 18 to 16 found in the prepared enameloid (somewhat different from human tooth enamel) of the shark teeth. Sharks constantly exchange water with their environment, so the isotopic oxygen ratio found in the teeth is directly regulated by water temperature and salinity.

With assumptions made about temperatures, the group was able to focus on extrapolating salinity levels of the water.