Sharks may struggle to feed efficiently in the future as ocean acidification threatens to erode their teeth, according to new research. Shark jaws carry multiple rows of teeth, with new ones quickly replacing lost or damaged teeth, but rapidly acidifying oceans could accelerate tooth wear beyond their replacement rate. This could impact shark populations and, in turn, disrupt marine ecosystem stability.
Ocean acidification occurs as oceans absorb carbon dioxide, lowering pH levels. By 2300, projections suggest average ocean pH could drop from 8.1 to 7.3, a shift that could have profound effects on marine life. To study this, researchers exposed 60 naturally shed blacktip reef shark teeth to tanks replicating current and projected acidic conditions. After eight weeks, teeth in the more acidic water showed about twice as much damage, including increased root corrosion and altered serrations, said lead author Maximilian Baum of Heinrich Heine University.
Sharks already face threats such as prey shortages from overfishing, and dental erosion could compound these problems. Even moderate pH drops may affect species with fewer teeth or slower replacement rates. Previous studies have shown acidification damages shells, corals, mussels, and shark denticles, and this study demonstrates its potential effects on apex predators.
Baum notes that sharks may adapt by increasing tooth replacement and strengthening damaged teeth. Lisa Whitenack, a shark tooth expert at Pennsylvania’s Allegheny College, agreed, suggesting corroded teeth may still function effectively, but further research is needed to determine if tooth damage reduces sharks’ ability to hunt successfully.
Reducing human-caused CO₂ emissions remains crucial to mitigate these risks and protect marine ecosystems.
