For those who fear sharks, the idea of toothless sharks might seem appealing. Though, a recent study reveals that ocean acidification could jeopardize these apex predators by compromising their teeth, which are essential for survival.

Sharks possess multiple rows of teeth that are continuously replaced.However, the increasing acidity of the oceans is causing damage to shark teeth, possibly outpacing their natural replacement rate. According to the study, sharks with compromised teeth may struggle to feed efficiently, which could “potentially affect shark populations and marine ecosystem stability.”

Ocean acidification results from the absorption of carbon dioxide, triggering a chemical reaction that lowers pH levels. Projections indicate that by the year 2300, oceans could become substantially more acidic, with pH levels dropping from the current average of 8.1 to 7.3. The study warns that this shift will have “profound implications for marine organisms”.

To investigate the effects of acidification, researchers maintained 60 naturally shed shark teeth in artificial seawater tanks.One tank mirrored the current ocean pH of 8.1, while the othre simulated the projected pH of 7.3. The teeth, collected from a German aquarium, originated from six male and four female blacktip reef sharks.

After eight weeks, the teeth in the more acidic tank exhibited approximately twice the damage compared to those in the control tank, according to Maximilian Baum, the study’s lead author and a researcher at Heinrich Heine University’s Institute for Zoology and Organismic interactions. He noted effects such as “increased root corrosion … and altered serration.”

Dental problems would exacerbate the challenges sharks already face, including prey scarcity due to overfishing.

Reducing human-caused CO2 emissions is crucial to mitigating ocean acidification. Previous studies have indicated that acidification also damages denticles, tooth-like scales on shark skin.

Baum suggests that even moderate pH declines could disproportionately affect more vulnerable shark species, such as those with fewer rows of teeth or slower replacement rates.

Expert Opinions and Potential Adaptations

“I think there will be effects on the teeth of ocean predators in general when they are highly mineralised structures like we have in sharks,”

“I think there will be effects on the teeth of ocean predators in general when they are highly mineralised structures like we have in sharks,” said Baum.

Previous research has demonstrated that acidification negatively impacts shells, corals, and mussels. “And that was also the reason why we did this study, to show us the effects on larger predators,” Baum explained.

Optimistically, Baum suggests that sharks might adapt to these changes by accelerating tooth replacement and enhancing tooth strengthening and repair mechanisms.

Lisa Whitenack,a shark tooth expert and professor at Pennsylvania’s allegheny College,who was not involved in the study,stated that the new research reinforces earlier findings on shark teeth and acidification. She also proposed that tooth replacement might keep pace with the damage caused by acidification and noted that even corroded teeth could still be functional.

“It will be engaging to see in future studies if the damage to teeth seen in studies like this one results in a functional effect on a tooth’s ability to do its job … [and if] damaged teeth can still cut or puncture prey,” said Whitenack.