Bleached Elkhorn coral in Dry Tortugas National Park
Bleached Elkhorn coral in Dry Tortugas National ParkShown here is a colony of the threatened Elkhorn coral, Acropora palmata, in Dry Tortugas National Park that has become "bleached," that is, lost all its algal symbionts (also called zooxanthellae) because of the summer 2023 ocean-heat wave.