Sharks could struggle to feed effectively in the future due to ocean acidification, potentially destabilizing marine ecosystems, a new study warns. Shark jaws carry multiple rows of teeth, constantly replaced as old ones are lost, but rapidly acidifying oceans are damaging teeth faster than they can be renewed. Sharks with compromised teeth may find it harder to hunt, affecting populations and the wider ecosystem.
Ocean acidification occurs when oceans absorb carbon dioxide, lowering pH levels. By 2300, oceans could drop from a current average pH of 8.1 to 7.3, a change expected to have “profound implications for marine organisms.” To examine the effects, researchers placed 60 naturally shed blacktip reef shark teeth in artificial seawater tanks at current and projected pH levels. After eight weeks, teeth in the more acidic water suffered roughly double the damage, including root corrosion and altered serration, according to lead author Maximilian Baum of Germany’s Heinrich Heine University.
Dental stress adds to existing pressures on sharks, such as prey shortages from overfishing. Even moderate acidification could affect species with fewer teeth or slower replacement rates. Previous studies have shown that acidification harms shells, corals, and mussels, prompting this research to explore impacts on larger predators.
Baum is cautiously optimistic, suggesting sharks might adapt by increasing tooth replacement and strengthening repairs. Lisa Whitenack, a shark tooth expert not involved in the study, noted that corroded teeth might still function and emphasized the need for further research to determine how damage affects sharks’ ability to cut or puncture prey. Reducing human-driven CO₂ emissions remains crucial to mitigating these risks.
