Florida Keys coral reefs under threat as record-high water temperatures trigger early bleaching

Florida Keys coral reefs are facing an early threat this summer as record-high water temperatures are causing stress and potential endangerment to their health.

"The corals are pale, it looks like the color’s draining out," said Lesneski, who has spent several days on the reefs over the last two weeks. "And some individuals are stark white. And we still have more to come."

Scientists with NOAA this week raised their coral bleaching warning system to Alert Level 2 for the Keys, their highest heat stress level out of five. That level is reached when the average water surface temperature is about 1.8 degrees Fahrenheit above the normal maximum for eight straight weeks.