A hot 2017 August and September that turns up the heat on ocean waters could increase the chances of coral bleaching along the Florida Keys reef tract, cautions the Coral Bleaching Early Warning Network.
In July, “a total of 76 BleachWatch observer reports were received ... with 36 reports indicating isolated colonies exhibiting signs of paling or partial bleaching,” network researchers say in an Aug. 1 summary.
The balance of reports “indicated that no significant signs of coral bleaching were observed,” but continued warming of ocean waters above the current average of around 86 degrees Fahrenheit could put the Keys reef in an “Alert Level 1.”
“Paling” means living corals have started to expel some of the zooxanthellae, a symbiotic algae responsible that helps process food for the coral and gives the coral its color.
Fully bleached corals can turn ghost white. Corals affected by mild warm-weather bleaching might recover but extended bleaching can leave the corals susceptible to disease and death.
“At those sites where paling was noted, the overall percentage of corals exhibiting signs of thermal stress was mostly 1 to 10 percent,” says a summary from Mote Marine Laboratory staff, a Warning Network partner with the Florida Keys National Marine Sanctuary. “However, a few offshore and deep reef sites noted up to 30 percent of corals affected.”
Mountain, boulder, brain and fire corals were among species seen to experience paling in July. Windy weather may have helped moderate water temperatures.
“These isolated observations of paling and partial bleaching do not necessarily indicate that the onset of a mass bleaching event is currently underway,” the report says. “Continued field observations are needed as more widespread coral bleaching could potentially develop if environmental conditions continue” become more likely to trigger bleaching.
To become active in monitoring Keys corals, go to www.mote.org/bleachwatch.
The recently released documentary film “Chasing Coral” chronicles corals worldwide apparently suffering from a changing climate.
Kevin Wadlow: 305-440-3206