Summer temperatures and light winds at the Florida Keys reef have increased reports of coral bleaching. The Coral Bleaching Early Warning Network on Monday issued a “warning” for more coral bleaching, as water temperatures at the reef near 87 degrees Fahrenheit.
Reports submitted by divers to Mote Marine Laboratory on Summerland Key showed corals on 18 of 21 reefs showed signs of paling, or starting to turn white. Reports were received from Key Largo through the Lower Keys. About 10 percent of corals were affected at those reefs. “However, one Lower Keys shallow inshore site noted 50 to 75 percent of coral affected,” network coordinator Cory Walter reported.
“These isolated observations of paling and partial bleaching do not necessarily indicate that the onset of a mass bleaching event is currently underway,” she added, but continued “temperature stress” could change then situation.
Corals are sensitive to extreme hot or cold temperatures. In the more common summer bleaching, the corals expel algae that feeds the corals and gives the corals their color. Corals can recover from bleaching, but an extended period without the algae can kill corals.
“When a coral bleaches, it expels its zooxanthellae [algae], and can die within a matter of weeks unless the zooxanthellae populations are able to recover,” according to the National Oceanic and Atmospheric Administration.
For information on filing coral-bleaching reports, contact the BleachWatch program at www.mote.org/bleachwatch.