Climate Change Could Be Wearing Down Sharks’ Teeth

Frontiers in Marine Science

A new study indicates climate change could erode not only coastlines: sharks' teeth may be next. Researchers from Heinrich Heine University in Düsseldorf suggest humans are responsible for increased absorption of carbon dioxide by oceans leading to ocean acidification which could change the mineral defense in shark teeth.

At a pH of 7.3, we observed surface damage such as cracks and holes, increased root corrosion, and structural deterioration. Additionally, the surface morphology was more irregular, which can weaken the structure of the teeth and make them more susceptible to breaking.

In lab tests on blacktip shark teeth in acidic water with a projected future pH of 7.3 (expected by 2300) demonstrated cracks, corrosion, and structural damage in their teeth that were far worse than only pH 8.1 (current ocean conditions). While sharks typically shed and regrow teeth, the likelihood of meaningful change in teeth development would take longer and would be harder and consume more energy.

Even moderate decreases in pH levels can impact more sensitive species with slower tooth replacement cycles or have a cumulative effect over time. For sharks, it is certainly very important that ocean pH values remain close to the current average of 8.1.

The implications extend well beyond sharks. Sharks are apex predators and sharks disappearing may destabilize an entire marine food web. For sharks, the study should serve as a cautionary tale that human-induced changes in pH, even in slight manners, can lead to cascading effects through ocean ecosystems and that human input on climate change is likely altering the ocean in ways we are only starting to figure out.

References:

https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2025.1597592/full