Environmental activists are petitioning the federal government to put 83 coral species on the endangered species list.

They say global warming and ocean acidification are threatening the corals with extinction.

The Center for Biological Diversity said last week that the coral species in question are found in Hawaii, Florida and U.S. territories in the Caribbean and the Pacific.

The National Oceanic and Atmospheric Administration must respond to the group's petition within 90 days and decide within a year whether listings are warranted.

Warm ocean temperatures can cause corals to expel algae they rely on for growth, resulting in what's called bleaching.

Bleaching episodes can kill coral if they occur often and last for long periods.

The center said ocean acidification is also hurting the ability of corals to build their protective skeletons, the center said in a news release.

“;Coral reefs are among the world's most endangered ecosystems and provide an early warning of impacts to come from our thirsts for fossil fuels, said Miyoko Sakashita, oceans director of the center.