Marine Heat Wave Devastates Florida Keys Coral Reefs
After experiencing record high ocean temperatures last summer, five out of seven iconic reefs in the Florida Keys are now found with extensive coral damage, according to an investigation by the National Oceanic and Atmospheric Administration (NOAA)’. Teams from NOAA’s “Mission: Iconic Reefs” program, alongside Mote Marine Laboratory & Aquarium and the Coral Restoration Foundation, conducted studies at 64 spots across Carysfort Reef, Horseshoe Reef, Sombrero Reef, Looe Key Reef, and Eastern Dry Rocks. Their findings revealed that only around a fifth of almost 1,500 staghorn corals surveyed are still alive.
Last July’s high sea temperatures, which often exceeded 90 degrees and reached over 100 degrees in some areas, caused mass coral deaths around the Florida Keys. These high temperatures lead to a phenomenon known as coral bleaching – when corals expel the algae living within their tissue that gives them their color, turning them white. The reefs in the Keys were hit the hardest during this marine heat wave, driving the NOAA and other institutions into a race against the clock to save as many dying and bleached corals as possible by moving them to land-based nurseries. Sadly, not all corals could be saved, such as the elkhorn coral at Horseshoe Reef, which deeply saddened local marine researcher, Katey Lesneski.
In an assignment last August to evaluate corals at the seven iconic reefs, the NOAA team reported signs of bleaching or partial bleaching in about 90% of the surveyed elkhorn and staghorn corals. Furthermore, they found that only Carysfort and Horseshoe Reefs – the two most northern reefs surveyed – still had living staghorn coral. At Carysfort Reef, Sombrero Reef and Eastern Dry Rocks, live elkhorn coral were discovered in three spots but none were found at Looe Key Reef in the lower Keys.
These findings are vital in understanding the impact of the unprecedented marine heat wave on the coral throughout the Florida Keys and offers a worrying glimpse into the future of the world’s coral in a warming world, says Sarah Fangman, the Florida Keys National Marine Sanctuary superintendent. She stresses the urgent need to update regulations to protect these vulnerable ecosystems.
Despite reporters stating that corals can survive bleaching, this process causes significant stress to the reefs and starves corals of their primary food source – the zooxanthellae algae. Considering the devastation last year, NOAA has updated its alert system for coral reefs by adding levels 3, 4, and 5 to provide a more detailed scale for describing coral bleaching events.
To address the issue, “Mission: Iconic Reefs” plans to restore nearly three million square feet of coral across the seven surveyed reefs. This will be done through an innovative scheme that grows and transplants corals. The aim is to restore diversity and environmental function to the reels by increasing coral cover to a sustainable level. Over history, factors like hurricanes, disease, and bleaching have contributed to the deterioration of Florida’s reefs which are vital habitats for various ocean life.
Recently, a coral scientist in Australia has warned that we may witness more mass coral bleaching and mortality in the future, predicting it to occur in 2024 based on historical climate data and patterns.