In a race against time, multiple organizations are working to save the reef that runs along the Florida Keys during a heat wave that has already led to historic coral bleaching.

Up and down the chain of islands that form the Florida Keys, coral rescue groups and government and academic institutions have mobilized to save the coral from a historic bleaching event that experts say threatens the viability of the third-largest reef tract in the world. They’ve been working long days and weekends in blistering heat for weeks to get as many specimens as they can onto land amid reports of some reef tracts experiencing near total mortality.