Sea surface temperatures are rising around the world, but the problem is pronounced in South Florida, according to a series of studies published by researchers at the University of South Florida College of Marine Science.
South Florida’s estuaries have experienced rapid warming over the past two decades, including a record-breaking marine heat wave in 2023.
Using satellite data, the researchers found that sea surface temperatures in four estuaries in South Florida have risen faster than sea surface temperatures globally and in the Gulf of Mexico. The findings, published in Environmental Investigation Letters And Estuaries and coasts, paint a disturbing picture for the marine life that calls Florida home.
“Temperatures in South Florida’s estuaries are rising not only faster than the global average, but also faster than temperatures in the open Gulf of Mexico,” said Chuanmin Hu, professor of physical oceanography at the University of South Florida and co-author author of the study. recent papers. “We even saw more responses within the estuaries to last year’s marine heatwave.”
According to the authors, sea surface temperatures in Florida Bay, Tampa Bay, St. Lucie Estuary and Caloosahatchee River Estuary have risen about 70 percent faster than in the Gulf of Mexico and 500 percent faster than in the oceans over the past two decades. Temperatures are expected to take their toll on marine life.
Estuaries are nurseries where many marine animals begin their lives. South Florida’s estuaries are home to crucial habitats such as seagrass meadows, and adjacent waters in the Florida Keys are home to world-famous coral reefs. These can be affected by rising water temperatures.
“Algae, seagrass and coral are all sensitive to temperature changes,” Hu said. “Algae prefer warm water, which can increase the size and frequency of blooms. Meanwhile, seagrass and coral undergo stress when the water gets too warm.”
The researchers hope to work with colleagues at the Florida Fish and Wildlife Conservation Commission and the National Oceanic and Atmospheric Administration to investigate the potential impacts of water temperatures on seagrass and coral populations in South Florida.
The researchers speculated about possible causes for the high rates of warming in South Florida’s estuaries, including evaporation, water capacity and residence time (the amount of time water spends in an estuary). No single factor has been found to be dominant.
Ongoing research by Hu and Jing Shi, a doctoral candidate in Hu’s lab and first author on the papers, will explore another peculiar observation: The accelerated warming observed in South Florida estuaries has not been observed in other estuaries in the region.
“Not every estuary around the Gulf of Mexico behaves this way,” Hu said. “These temperature changes appear to be unique to South Florida estuaries.”
The next question, Hu said, is how long this accelerated warming in South Florida will last.
“We expect that the rate of warming will eventually equilibrate with that of the open Gulf of Mexico,” he said. “We just don’t know when that will happen.”
This research was supported by a grant from the NASA Water Resources Program and a presidential grant from USF.
