Sharks may struggle to feed efficiently in the future as ocean acidification damages their teeth, potentially destabilising marine ecosystems, new research suggests. The study, led by Maximilian Baum of Heinrich Heine University in Germany, found that increased acidity corrodes shark teeth and could accelerate tooth loss beyond natural replacement rates.
Ocean acidification results from rapid carbon dioxide absorption, which lowers pH levels. Projections indicate that by 2300, ocean pH could drop from the current average of 8.1 to 7.3, with profound implications for marine life. The researchers tested this by keeping 60 naturally shed teeth from blacktip reef sharks in artificial seawater tanks at pH 8.1 and 7.3 for eight weeks.
Teeth in the more acidic tank suffered about twice as much damage, including increased root corrosion and altered serration, according to the study published in the journal Marine Biology. This dental stress adds to other threats sharks face, such as prey shortages from overfishing.
Reducing human-caused CO2 emissions is vital to mitigate ocean acidification, the researchers said. Previous studies have shown acidification harms shells, corals, and mussels, and this work extends those findings to larger predators. However, Baum noted that sharks may adapt by increasing tooth replacement rates or improving tooth strengthening and repair.
Lisa Whitenack, a shark tooth expert at Allegheny College not involved in the study, said the research adds to initial findings on shark teeth and acidification. She suggested that tooth replacement might keep pace with acidification losses and that corroded teeth might still be effective. Future studies will need to determine if damaged teeth can still cut or puncture prey effectively.
