The Florida Barrier Reef is experiencing an unprecedented threat. Blame for a marine heat wave capable of bringing the temperature of the waters of the Keys – shallow and also for this less with lower thermal capacity than the open sea – to temperatures of the order of 90 degrees Fahrenheit (over 32 degrees Celsius) with peaks of 97 Fahrenheit, above 36 Celsius. Values, these, measured on the surface around the coast, and never detected since the satellites began to record the thermal data of the ocean surfaces.
A status which, as it is sadly known by now, jeopardizes the health – among other organisms – of the coral reef, which is one of the first assets of the area. Scholars are particularly worried because this is already happening in July, ie at the beginning of summer, when the sea, even more than the mainland which is already close to the possible peak season, instead continues to warm up. In short, August, and even September, could be even worse.
The known consequence of so much stress, accumulated since the beginning of the season, is the dreaded bleaching, destructive and irreversible, in fact the death of large sections of the fascinating living organism which is itself a source of life and refuge for a myriad of other species . He told the Independent Mark Eakin, of the International Coral Reef Society. The bleaching unfortunately it is an increasingly recurring phenomenon and occurs as a consequence of the stress to which the barriers are subjected when the water temperature rises and/or there is a lack of nutrients.
The great climate crisis has intensified the frequency of the phenomenon, which is particularly acute with “El Niño”, the cycle phenomenon that induces the warming of ocean waters, and which is underway in recent months. It goes without saying that global warming due to the abuse of fossil fuels and gases, and in further acceleration, does the rest.
“We are entering new territories – says Derek Manzello, ecologist who coordinates the NOAA reef control program (National Oceanic and Atmospheric Administration to the NY Times. – To be frank, it is depressing”.
Liv Williamson, of the future reef lab at the University of Miami explains that there have already been reports of bleaching from Belize, “which is very alarming, so early in the summer.” And he adds that global projections suggest a 90 percent probability that the phenomenon will manifest itself severely in many reefs, including those of the equatorial islands of the Pacific, the tropical Panamanian side of the Pacific, and still the Caribbean coast of the Central America. In addition, of course, to Florida.
“It’s just July. This heat is going to build up and these corals are going to have to endure dangerously hot conditions for much longer than normal,” Williamson told the Associated Press. Corals have a symbiosis, a form of interaction that it benefits both parties, with small algae, zooxanthellae, living in their cells.The algae get nutrients and carbon dioxide, while the coral gets energy from the products of photosynthesis.
A change in temperature, even of one to one and a half degrees, literally collapses this symbiosis. And without the help of algae, the coral changes from its natural and healthy brown color and progressively whitens. A process, bleaching, which is not necessarily lethal. However, the chances of death rise inexorably if the temperatures involved are particularly high. And the thermal values of the Florida water – explains Manzello – have been 2 degrees Celsius above the norm for a couple of weeks already.
A study released by NOAA in 2022 showed that disease and bleaching from the climate crisis have already eroded 70 percent of Florida’s reef. And this, among other things, translates into a potentially huge economic loss for a state where the reef generates billions of dollars in revenue due to its ability to attract tourists and fishing enthusiasts.
Katey Lesneski, who monitors “Mission: Iconic Reefs,” a NOAA-branded project that aspires to the full recovery of seven reef areas in the Keys, checked the bleaching over the weekend. She says she saw the initial stage of the phenomenon in coral reefs up to 18 meters deep just off the coast of Islamorada. “The corals were much lighter than normal, usually showing strong yellows, greens, browns and oranges. They looked like someone had doused them with bleach.”