Florida Keys Reefs Bleach As Temperatures Rise

Some Florida Keys coral reefs are losing their color weeks earlier than normal this summer because of record-high water temperatures, meaning they are under stress and their health is potentially endangered, federal scientists said, Terry Spencer and Patrick Whittle reported for the Associated Press (AP).

Photo Insert: Scientists with NOAA this week raised their coral bleaching warning system to Alert Level 2 for the Keys.

The corals should be vibrant and colorful this time of year, but are swiftly going white, said Katey Lesneski, research and monitoring coordinator for Mission: Iconic Reefs, which the National Oceanic and Atmospheric Administration (NOAA) launched to protect Florida coral reefs.

“The corals are pale, it looks like the color’s draining out,” said Lesneski. “And some individuals are stark white. And we still have more to come.” Coral reefs are made up of tiny organisms that link together.

The reefs get their color from the algae that live inside them and are the corals’ food. When temperatures get too high, the coral expels the algae, making the reefs appear white or bleached.

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 (1 degree Celsius) above the normal maximum for eight straight weeks.

Surface temperatures around the Keys have been averaging about 91 degrees (33 Celsius), well above the normal mid-July average of 85 degrees (29.5 Celsius), said Jacqueline De La Cour, operations manager for NOAA’s Coral Reef Watch program. Previous Alert Level 2s were reached in August, she said.

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