Sharks could face difficulties feeding efficiently in the future as ocean acidification threatens to weaken their teeth, potentially affecting both their populations and marine ecosystem stability. Shark jaws are equipped with multiple rows of teeth that are continuously replaced, but acidifying oceans could accelerate damage beyond their natural replacement rates, the study warns.
Ocean acidification occurs when the oceans absorb carbon dioxide from the atmosphere, lowering pH levels. By 2300, projections suggest ocean pH could drop from 8.1 to 7.3, with “profound implications for marine organisms,” according to the research. To examine the effects, scientists placed 60 naturally shed blacktip reef shark teeth in artificial seawater tanks replicating current and projected acidic conditions. After eight weeks, teeth in the more acidic tank experienced twice as much damage, including root corrosion and altered serrations, said lead author Maximilian Baum of Heinrich Heine University.
Sharks already face pressures from overfishing, and dental degradation could compound these challenges. Even moderate acidification could particularly impact species with fewer rows of teeth or slower replacement rates. Previous studies have shown that acidification also harms shells, corals, mussels, and the denticles on sharks’ skin.
Researchers remain cautiously optimistic. Sharks may adapt by increasing tooth replacement and strengthening, while corroded teeth might still function effectively. Lisa Whitenack, a shark tooth expert not involved in the study, noted that future research will need to determine whether damaged teeth can still perform the critical role of cutting or puncturing prey. Reducing CO₂ emissions remains crucial to mitigating the threat of ocean acidification on marine predators.
