Water temperatures soar around Florida, causing more coral bleaching

Surface temperatures reached as high as 95 degrees Fahrenheit in the Florida Keys this week.

David Knowles
·Senior Editor
Updated ·4 min read
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A map graphic uses color to indicate high water temperatures in the Gulf of Mexico.
The Gulf of Mexico is experiencing water temperatures far above normal. (NASA)

An ongoing ocean heat wave is pushing water temperatures in the Gulf of Mexico into the mid 90s and threatening the survival of coral reefs.

Along Florida's southwest coast, surface temperatures were recorded this week as roughly 5 degrees above normal, and reached as high as 95 degrees Fahrenheit in the Florida Keys.

Coral bleaching

Bleached fire coral contrasts against healthy coral.
Bleached fire coral, center, contrasts against healthy coral off Summerland Key, Fla., in 2005. (Wilfredo Lee, File/AP)

Extended periods of exceedingly warm water, such as those that have been linked to climate change, are potentially harmful to coral reefs, causing so-called bleaching events.

"When water is too warm, corals will expel the algae (zooxanthellae) living in their tissues causing the coral to turn completely white," the National Oceanic and Atmospheric Administration (NOAA) states on its website.

That's especially worrisome for the Florida Keys, where less than 5 percent of coral cover still remains.

"The Keys are in a 'Hot Spot' as per @CoralReefWatch," Jeff Berardelli, chief meteorologist at WFLA-TV in Tampa, wrote in a Sunday Twitter thread. "With favorable weather patterns for stagnation the next 10 days + and hot sea surface temps, we should be watching this area closely to see what kind of bleaching occurs."

In June, NOAA warned that "significant" coral bleaching was expected from mid-August through late September, with the possibility of "severe bleaching, significant mortality" over that period. Since then, water temperatures have spiked.

Water warming faster

Kim Wood, assistant professor in the Department of Geosciences at Mississippi State University, noted Monday that the Gulf of Mexico is not just more bathlike than normal this summer. This year it heated up faster too.

Hurricane outlook

A satellite image shows Tropical Storm Arlene in the Gulf of Mexico west of Florida.
Tropical Storm Arlene becomes the first named storm of the Atlantic hurricane season, in the Gulf of Mexico west of Florida, on June 2. (NOAA via AP)

While there is little evidence to show that climate change is causing a greater number of tropical cyclones to form, there is plenty of research that shows warmer temperatures can result in stronger hurricanes.

Last week, citing "extreme anomalous warmth" in the Atlantic Ocean, forecasters at Colorado State University updated their outlook for this year's hurricane season.

"Their updated hurricane season outlook, released Thursday, now calls for an 'above-average' season with 18 named storms, of which nine will become hurricanes and four will reach major hurricane strength (with sustained winds of 111 miles per hour or higher)," the Tampa Bay Times reported. "That's five more named storms — and two more major hurricanes — than first predicted."

Simply put, warmer temperatures add more energy into the climate system. The arrival of the El Niño weather pattern is poised to usher in more record-breaking heat. Last week the world broke the record for the hottest average day ever recorded for three consecutive days. That followed the finding that June was the hottest month ever recorded by humans, and that the planet has recorded its 532nd consecutive month of above-average temperatures.

But El Niño patterns also push the Pacific jet stream south, according to NOAA, and those winds could play a role in preventing the development of hurricanes.