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Record-High Seawater Temperature Off Florida’s Coast Raises Concerns For Marine Life

Water temperatures reaching hot tub levels threaten coral reefs and could have lasting ecological impacts.

Scientists are sounding the alarm after water temperatures, similar to those found in hot tubs, were recorded off the tip of Florida. If the temperature recordings are confirmed, it could be the hottest seawater ever measured in the world.

“A buoy in Manatee Bay, which is about 40 miles south of Miami, hit 101.1 degrees Fahrenheit at a depth of 5 feet (1.52 m) Monday evening. For comparison, that’s the “ideal” temperature for a hot tub,” said

“The 101.1-degree temperature reading in Manatee Bay may not be confirmed. He says the shallow water and darker seaweed in the area help the water absorb heat, which could have influenced the reading,” said AccuWeather Meteorologist Brandon Buckingham. 

While this reading could go down in history, there are no official records of high sea surface temperatures, according to AccuWeather Meteorologist and Social Media Producer Jesse Ferrell. That is because water temperatures are sampled at many different depths, so there is no way to determine the all-time record.

Comparisons of different water temperatures.  The water temperatures are sampled at many different depths, so there is no way to determine the all-time record.ACCUWEATHER.

Despite there being no official records, a study from 2020 proposed that a 99.7- degree temperature reading in Kuwait Bay, in the northwestern Arabian or Persian Gulf, in July 2020 was the world’s highest seawater temperature on record.

In addition to the Manatee Bay reading from Monday evening, several other buoys across the southern tip of Florida recorded temperatures in the middle to upper 90s this week.

Compared to daily historical average sea surface temperatures, water temperatures off Florida’s southern tip are roughly 5.4 degrees Fahrenheit above normal.

Ocean water temperatures compared to normal on Wednesday morning July 25, 2023. (NOAA). ACCUWEATHER.

Buckingham says this is partially due to a consistent dome of high pressure over the region.

“The area of high pressure that has been frequently set up over Florida and adjacent waters commonly features low winds, which does not churn or upwell any cooler water to the surface,” Buckingham said. “It also has resulted in below-average rainfall.”

Without rain or wind, it’s much harder for water temperatures to decrease.

“Often times the only way to get water temperatures to drop significantly is when a strong tropical system moves through the area to churn and upwell cooler water from deeper down,” said Buckingham.

Experts say that these high water temperatures could mean “complete mortality” of coral reefs. While there isn’t a high concentration of coral reefs in Manatee Bay, other areas of Florida, such as Cheeca Rocks in the Florida Keys, are at risk.

Last week, National Oceanic and Atmospheric Administration (NOAA) raised its coral bleaching warning system to an“ Alert Level 2” off the southern coast of Florida following several days of above-average water temperatures. The alert system from NOAA rates heat stress on coral reefs out of five levels, with five being the highest.

According to NOAA, coral bleaching occurs when the ocean’s environment changes. The coral becomes stressed and expels algae, which lives in its tissue, and provides distinctive color and energy. As the algae departs, the coral begins to fade until it looks like it’s been bleached. NOAA notes that if the water temperatures remain high, the coral becomes severely bleached. In that case, the coral becomes more susceptible to disease and death.

“If corals bleach and die, a significant trickle-down effect for marine life will then follow,” Buckingham said.

Photos and videos of Cheeca Rocks, shared by NOAA monitoring specialist at Florida Keys National Marine Sanctuary Andrew Ibarra, showed the shocking toll the high water temperatures have already taken on the reefs.

“I found that the entire reef [at Cheeca Rocks] was bleached out,” said Ibarra to CNN.” Every single coral colony was exhibiting some form of paling, partial bleaching or full-out bleaching.”

The reefs, which were once a colorful area full of life, stood white and lifeless in Ibarra’s images.

“First observed in the early 1980s, mass coral bleaching has become one of the most visible and damaging marine ecological impacts of persistently rising ocean temperatures,”said NOAA. “Mass bleaching events around the globe are often lasting many months and becoming an annual event and are impacting coral reefs that never bleached before.”

Produced in association with AccuWeather

Edited by Judy J. Rotich and Newsdesk Manager

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