Sharks are famous for fearsome teeth, but ocean acidification could make them weaker

1 / 4

FRIEDERIKE_KREMER

In this undated handout photo provided by Heinrich Heine University Duesseldorf in January 2026, a blacktip reef shark swims at Sealife Oberhausen in Oberhausen, Germany. (Maximilian Baum/Heinrich Heine University Duesseldorf via AP)