The climate crisis may be a threat to the existence of sharks. The acidification of oceans is decaying sharks' teeth. Scientists already know that increasing ocean acidity is damaging corals and sea creatures with shells. Biologists looked at whether shark teeth are at similar risk. Many sharks swim with their mouths open and are constantly exposed to seawater. The researcher concluded that even the teeth of sharks are now vulnerable to damage.

The researcher analyzed teeth from blacktip reef sharks. He put the teeth in separate water tanks for eight weeks. The salt water in one had an acidity level similar to current ocean averages. The water in the other tank was more acidic. The teeth in the more acidic water had visible damage, including cavities, root decay, and structural deterioration. Ongoing damage could impact how sharks feed. This could trigger "domino effects" across marine ecosystems.