A new study suggests that ocean acidification could leave sharks struggling to feed efficiently, threatening marine ecosystem stability. Shark jaws carry multiple rows of teeth, which are continuously replaced, but rapidly acidifying oceans may accelerate tooth loss beyond the rate of replacement. This could impair sharks’ ability to hunt and survive.
Ocean acidification occurs as the oceans absorb excess carbon dioxide, lowering pH levels. By 2300, average ocean pH could drop from 8.1 to 7.3, potentially affecting a wide range of marine organisms. Researchers tested the effects by placing 60 naturally shed blacktip reef shark teeth in artificial seawater at current and projected pH levels. After eight weeks, teeth in the more acidic water showed roughly twice the damage, including root corrosion and altered serrations, according to Maximilian Baum of Heinrich Heine University.
Sharks already face pressures from prey shortages caused by overfishing, and tooth degradation could worsen the threat. Even moderate acidification could impact species with fewer teeth or slower replacement rates. Baum notes that the findings may apply to other highly mineralized predators as well. Previous studies have shown similar effects on shells, corals, and mussels, highlighting the broad implications of acidification.
There is some optimism, as sharks might adapt by replacing teeth more frequently or strengthening existing ones. Lisa Whitenack, a shark tooth expert not involved in the study, emphasized that damaged teeth might still function effectively, but future research is needed to determine whether acidified teeth can maintain their ability to cut and puncture prey. Reducing CO₂ emissions remains critical to protect sharks and the broader marine environment.
