Scientists Say ‘Scary’ Sea Water Temperatures Recorded Near Florida Keys

Gulf of Mexico beaches like Clearwater Beach pictured here on July 2, 2023, can be feel like bathwater in the summer, but this year's sea temperatures near Florida are among the highest ever recorded. Nanette Holt/The Epoch Times

A scientist has warned that the eyebrow-raising seawater temperatures off Florida—logged in one area at 107 degrees last month—is “scary” because it’s indicative of longer-term warming trends at sea.

According to satellite data from the University of South Florida, temperatures recorded in Florida Bay—the stretch of water between the Florida Keys and the mainland—on July 24 included some as high as 113 degrees Fahrenheit.

Sea temperatures in the area are the warmest on record going back to 1981.

If your body temperature, typically 98.6 degrees, went that high, you'd likely suffer brain damage.

If a hot tub were that hot, you may deem it too hot to get into. The CDC and the Consumer Product Safety Commission already think so: they have set 104 degrees as the maximum safe hot tub temperature.

“The warming in Florida Bay is scary,” Dr. Chuanmin Hu told The Epoch Times in an email.

Dr. Hu, of the University of South Florida’s College of Marine Science, co-authored a paper on the subject published in Environmental Research Letters in December 2022 with his graduate student Jing Shi.

“That’s a hot bath, for sure.”

He said the 107-degree figure—42 degrees Centigrade—was conservative and may have been as high in some cases as 45 degrees Centigrade, or 113 degrees Fahrenheit.

Fish swim among coral grown on the retired Naval Landing Ship Dock Spiegel Grove six miles off Key Largo in 2022. Corals like these are in danger from high sea temperatures, scientists say. Frazier Nivens/Florida Keys News Bureau via AP

Waters close to shore show warmer temperatures than those further out to sea. But both the Atlantic Ocean and the Gulf of Mexico are, as of this summer, “way above historical norm,” Ms. Shi told The Epoch Times in an email.

Those temperatures are “beyond incrementally higher than norms,” she said.

Warmer sea temperatures may cause tropical storms or hurricanes, which pick up heat from the sea, to intensify faster, she said.

Rising sea temperatures around Florida may intensify tropical storms, scientists say. This photo was shot at the Naval Station Key West during Tropical Storm Fay on Aug. 18, 2008. James E. Brooks/U.S. Navy via Getty Images

Ecologically, scientists are studying various effects. They saw coral bleaching in the Florida Keys Reef Tract during high temperatures in 2014, Ms. Shi and Mr. Hu said in their study.

Algae live inside coral, giving it coloration and nutrients through photosynthesis. The coral, when stressed by heat, expels the algae and turns white. That’s called coral bleaching, according to the Atlantic Oceanographic and Meteorological Laboratory.

Australian research suggests soft corals may fare better than hard ones during marine heat waves.

Dense turtle grass beds were destroyed in Florida Bay in 2015, Ms. Shi and Mr. Hu said in their study.

Scientists think that was caused by a combination of high water temperature, high salinity, and sulfide toxicity.

“A warm ocean also impacts metabolism of many marine mammals,” Ms. Shi told The Epoch Times.

Manatees are among the sea mammals endangered by extreme swings in sea temperature. Here, an orphaned manatee calf takes a bottle from a keeper at ZooTampa at Lowry Park in Tampa, Fla. on Jan. 13, 2022. Natasha Holt / The Epoch Times

More extremes in weather can also cause effects at the other end of the temperature scale, they wrote.

Cold winters in South Florida from 2009 to 2011 caused “mass mortality” of manatees and killed corals in the Florida Keys Reef Tract.

Seas experience heat waves, just like land areas do, the Atlantic Oceanographic and Meteorological Laboratory said.

A warming event lasting at least five days is considered a marine heatwave.

“What is most concerning is that heatwave conditions in the Gulf of Mexico have persisted approximately 5–6 months, longer than any widespread marine heatwave in the region on record [dating back to 1991],” the lab, operated by the National Oceanic and Atmospheric Administration (NOAA), said.

“Ocean temperatures around South Florida are the warmest on record for the month of July [dating back to 1981],” the lab said.

Ms. Shi and Dr. Hu looked at satellite temperature measurements from 2003 for the Gulf and Florida’s waters on both coasts.

The global ocean warming rate the past 20 years is 0.13 degrees Centigrade per decade, Ms. Shi told The Epoch Times. The Gulf’s rate is 0.4 degrees Centigrade. Florida Bay’s is 0.77 degrees per decade, while Barnes Sound, near Manatee Bay, is 0.79 degrees Centigrade.

“In other words, Barnes Sound is warming at a speed six times faster than global oceans,” Ms. Shi said.

The Gulf’s temperature increases over the past 20 years, though, are not evenly distributed.

It warmed the most in the waters off southwest Florida, in Florida Bay and up South Florida’s Atlantic coast, south and southeast of Louisiana, and in narrow bands along the Yucatan Peninsula and west from there along the Mexican coast.

Other areas showed cooling, with July 2023’s temperatures as much as two degrees cooler than the average of the July readings for the preceding 20 years.

Parts of the Gulf along the entire coast north of Tampa Bay and off the Florida Panhandle to Pensacola showed those cooler readings, as did Gulf waters off most of the Texas coast.

The seas north and northwest of Yucatan were cooler but not as much.

The cooler readings in those places, Dr. Hu said, are the result of “ocean upwelling,” where deeper, cooler water is brought up to the surface.