Sharks could face difficulties feeding efficiently as ocean acidification damages their teeth, potentially destabilising marine ecosystems, a new study has found. Researchers warn that rapidly acidifying oceans are corroding shark teeth faster than they can be replaced, threatening the survival of these apex predators.
The study, led by Maximilian Baum of Germany's Heinrich Heine University, exposed 60 naturally shed blacktip reef shark teeth to artificial seawater tanks. One tank mirrored current ocean pH levels of 8.1, while the other matched projected levels of 7.3 for the year 2300. After eight weeks, teeth in the more acidic tank suffered approximately twice as much damage, including increased root corrosion and altered serration.
Ocean acidification results from rapid carbon dioxide absorption, which lowers pH levels. Projections indicate a drop from the current average pH of 8.1 to 7.3 by 2300, with profound implications for marine life. Previous research has shown acidification harms shells, corals, and mussels, but this study highlights effects on larger predators.
Dental stress adds to sharks' existing challenges, such as prey shortages from overfishing. However, Baum suggests sharks may adapt by increasing tooth replacement rates and improving strengthening and repair. Lisa Whitenack, a shark tooth expert at Allegheny College, noted that future studies should examine whether damaged teeth can still cut or puncture prey effectively.
Reducing human-caused CO2 emissions is vital to mitigate ocean acidification. Even moderate pH drops could affect sensitive shark species with fewer tooth rows or slower replacement rates, the study warns.
