Acidified seas harm shark teeth: A study in Frontiers in Marine Science shows:

 

Due to rising CO₂ emissions, the pH level of the oceans is dropping – with consequences even for shark teeth. Researchers led by Maximilian Baum (Heinrich Heine University Düsseldorf, ElasmOcean) incubated teeth from blacktip reef sharks in differently acidic seawater.

 

At pH 7.3, as predicted for 2300, cracks, holes, and corrosion appeared. Although sharks can regenerate teeth, the pressure from additional stress factors such as overfishing and warming could overwhelm their adaptability. A warning signal for the vulnerability of marine predators.