Sharks could struggle to feed effectively in the future due to ocean acidification, potentially impacting marine ecosystem stability, a new study warns. Shark jaws carry multiple rows of teeth that are continuously replaced, but rapidly acidifying oceans may damage teeth faster than they can be replaced. Sharks with impaired teeth could face difficulties hunting, threatening both their populations and the broader marine food web.
Ocean acidification occurs as oceans absorb carbon dioxide, lowering pH levels. By 2300, projections suggest ocean pH could drop from 8.1 to 7.3, a change with “profound implications for marine organisms.” Researchers tested 60 naturally shed teeth from blacktip reef sharks in artificial seawater tanks at current and projected pH levels. After eight weeks, teeth in more acidic water showed about twice the damage, including root corrosion and altered serration, said lead author Maximilian Baum of Heinrich Heine University.
This dental stress compounds other threats, such as prey shortages from overfishing. Even moderate pH drops may affect sharks that have fewer teeth rows or slower replacement rates. Previous studies have shown acidification harms shells, corals, and mussels, and this study demonstrates similar risks for apex predators.
Baum noted that sharks might adapt by increasing tooth replacement or enhancing repair, while experts like Lisa Whitenack of Allegheny College suggest corroded teeth may still function. Further research will determine whether the observed damage impairs sharks’ ability to cut or puncture prey, highlighting the importance of reducing CO₂ emissions to protect ocean ecosystems.
