Sharks could lose their predatory edge as ocean acidification damages their teeth, potentially disrupting marine ecosystems, according to a new study. Researchers warn that increasing acidity may cause tooth loss to outpace replacement, leaving apex predators unable to feed efficiently.
Ocean acidification, driven by rising CO2 levels, lowers seawater pH. Current levels average 8.1, but projections for 2300 suggest a drop to 7.3. To test effects, scientists placed 60 naturally shed teeth from blacktip reef sharks in two artificial seawater tanks: one mimicking today's pH, another the future level.
After eight weeks, teeth in the more acidic tank showed double the damage, including root corrosion and altered serration, said lead author Maximilian Baum of Heinrich Heine University. The findings extend previous work on acidification harming shells and corals to larger predators.
Baum noted that even moderate pH drops could affect sensitive shark species with fewer tooth rows or slower replacement. However, he suggested sharks might adapt by increasing tooth replacement rates or strengthening teeth. Lisa Whitenack, a shark tooth expert not involved in the study, added that corroded teeth might still function effectively, making future research on functional impacts key.
Beyond dental issues, sharks face other pressures such as overfishing and prey shortages. Reducing CO2 emissions is crucial to mitigate ocean acidification, which also damages shark skin denticles.
