Ocean acidification could weaken shark teeth, study finds

A new study from Germany indicates that ocean acidification driven by rising carbon dioxide could weaken one of the ocean’s most formidable weapons: shark teeth. In a controlled experiment, researchers exposed discarded teeth from Blacktip reef sharks to seawater at current pH conditions and to a projected future level, observing more pronounced damage under the more acidic conditions. The findings suggest that even the highly mineralized teeth of apex predators may become more prone to cracking, corrosion and structural degradation as the oceans absorb more CO2.

In the experiment, scientists from Heinrich Heine University Düsseldorf placed plastic trays containing about eight weeks’ worth of discarded shark teeth in 20-liter tanks. Some teeth were kept in water at the current average ocean pH of 8.1, while others were exposed to a more acidic pH of 7.3, a level scientists project could characterize global oceans by 2300. The study examined teeth from a large sample drawn from conservation-acquired specimens, and tracked changes from surface condition to overall shape. After the eight-week period, teeth in the acidic water showed clear signs of wear: surface cracks, holes, root...