Thousands of corals being sheltered at lab from rising Florida ocean temperatures

By Ana Mengotti

Miami, Jul 26 (EFE) – Thousands of threatened corals from offshore nurseries and parent colonies off the Florida Keys are being taken by divers and scientists to an on-land laboratory to protect them from an unprecedented ocean heat wave.

At least 1,500 coral specimens that had been used to restore the reefs of that archipelago between the United States and Cuba are already at the Keys Marine Laboratory and more will arrive soon, KML Director Cindy Lewis told Efe on Wednesday.

She noted that this summer’s water temperatures are the highest she has ever observed.

According to the expert, corals are accustomed to living in waters of up to 86 F (30 C), but when the water gets as warm as 90 F (32.2 C), they become very stressed and expel the tiny single-celled algae known as zooxanthellae that live in their tissues and are a food source.

Without that algae, which are golden brown in color, the corals’ white skeletons are visible through their translucent skin – a heat stress-triggered phenomenon that has been given the name “bleaching.”

Lewis explained to Efe that bleaching is a sign that these marine invertebrates are suffering from stress and lack of food and are more vulnerable to diseases.

She also said the current bleaching episodes are worse than previous ones and that the corals used to appear pale when lacking algae but now have the color of dirty snow.


At the Keys Marine Laboratory, located in the city of Layton on the Florida Keys and part of the Florida Institute of Oceanography, the corals are placed inside seawater-filled tanks and kept at a regulated and constant temperature.

Lewis says each of the 60 240-gallon (908-liter) tanks can hold between 3,000 and 5,000 corals, or even more.

However, some of the corals that arrive at the laboratory for an expected two-month stay (roughly 10 percent of the total) are too discolored and stressed and cannot be saved, she told Efe.

The disappearance of the corals from the offshore nurseries and parent colonies would be a blow to restoration efforts at the barrier reef that stretches from north of Miami to the southernmost part of the Florida Keys, an archipelago that is a national marine sanctuary.


Also involved in the relocation of the corals is the University of South Florida, which hosts the Florida Institute of Oceanography.

Additionally, the Florida Aquarium, the Florida Fish & Wildlife Conservation Commission and private institutions are helping relocate corals from reefs to their temporary shelter.

Lewis said the situation is particularly worrisome because the usually hot month of August still lies ahead, adding that the effort to save Florida’s reefs involves hundreds of people and is extremely costly, but nevertheless is a necessary endeavor.

She noted that reefs support a multi-billion-dollar industry that encompasses tourism, underwater sports and recreational and commercial fishing,

They also are the first line of defense against hurricanes and a treasure trove of biodiversity, she said.

The Coral Restoration Foundation (CRF), which also works in the Florida Keys, said this week that its teams found a heat stress-triggered 100 percent mortality rate on July 20 at Sombrero Reef, a protected site off Key Vaca that is home to endangered coral species.

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