Florida ocean potentially the hottest seawater ever as temperatures reach hot-tub levels

The high temperatures have caused coral bleaching and even some coral death off the coast of Florida

The hottest seawater ever has potentially been recorded on the tip of Florida as temperatures exceeded 37.8C for two days in a row.

An initial reading on a buoy at Manatee Bay hit 38.4C on Monday evening, according to National Weather Service meteorologist George Rizzuto. On Sunday night the same buoy showed an online reading of 37.9C degrees.

But weather records for sea water temperature are unofficial, and there are certain conditions in this reading that could disqualify it for a top mark, meteorologists said.

It may not be accepted as a record as the area is shallow, has sea grasses in it, and may be influenced by the warm land in the nearby Everglades National Park.

'If you look at some official buoys run by national agencies, we've never seen a record breaking event like this before,' Jeff Masters, Yale Climate Connections meteorologist says

While there aren't official water temperature records, a 2020 study listed a 37.6C mark in Kuwait Bay in July 2020 as the world's highest recorded sea surface temperature.

“This is a hot tub. I like my hot tub around 37.8, 38.3C. That's what was recorded yesterday,” said Yale Climate Connections meteorologist Jeff Masters. Hot tub maker Jacuzzi recommends water between 37.8 and 38.9C. “We've never seen a record-breaking event like this before,” Masters said.

The devastating effects from prolonged hot water around Florida include coral bleaching and even some death in what had been one of the Florida Keys' most resilient reefs.

The sun shines on coral showing sign of bleaching at Cheeca Rocks off the coast of Florida. Credit: NOAA via AP

Coral bleaching is when, due to high water temperatures, corals loses their vibrant colour by expelling their algal food source and turn white.

National Oceanic and Atmospheric Administration (NOAA) researcher Andrew Ibarra, who took his kayak to the area because of the hot water, said: “I found that the entire reef was bleached out. Every single coral colony was exhibiting some form of paling, partial bleaching or full out bleaching.”

Some coral had even died, he said.

Experimentally-outplanted corals on January 2023, left, and the same coral on July 2023, after suffering from bleaching near Miami. Credit: NOAA and the University of Miami via AP

Until the 1980s coral bleaching was mostly unheard of around the globe yet “now we've reached the point where it's become routine,” said Ian Enochs, lead of the coral programme at the National Oceanic and Atmospheric Administration Atlantic Oceanographic and Meteorological Laboratory.

“This is more, earlier than we have ever seen,” Enochs said. “I’m nervous by how early this is occurring.”

This comes as sea surface temperatures worldwide have broken monthly records for heat in April, May and June, according to NOAA.

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