WASHINGTON — Officials with the National Oceanic and Atmospheric Administration say unusually warm ocean surface temperatures, or "marine heat waves" off the coast of South Florida could continue into the fall, threatening the health of marine ecosystems. 

What You Need To Know

  • NOAA forecasts marine heat waves around South Florida could continue through October

  • Chris Kelble, the director of the Ocean Chemistry and Ecosystems Division at NOAA, says these events can lead to the deterioration of marine ecosystems.

  •  He says that over time warm ocean temperatures can lead to the death of corals. 

Chris Kelble, the director of the Ocean Chemistry and Ecosystems Division at NOAA, says scientists began noticing anomalously high water temperatures in the Gulf of Mexico and off the coast of South Florida around January or February, and that this year’s are particularly intense and prolonged.

"Marine heat waves are basically when the temperatures of the ocean are above what is normal for a region, much like heat waves on land are," he said. "And typically it's defined as being greater than 90% of all observations. So, it has to be in that really high range of observations for it to be considered a heatwave."

In July, a sensor in shallow water in Manatee Bay recorded a temperature of more than 101 degrees, possibly setting a global record. Kelble said the excessive heat is concerning, as are other trends. 

"When you look at the Gulf of Mexico as a whole, it had never gotten above 87 degrees as an average temperature on any day — I think it was actually a weekly average, and we got up to 88 this year," he said. "So, we were more than a degree above what had been observed before throughout the entire Gulf of Mexico, which is which is a pretty large region."

And while a degree or two may not sound like much, Kelble said it can mean the difference between life and death for fish and corals over a prolonged period of time. He said warmer water driven by climate change is not the only factor threatening these fragile ecosystems. 

“Usually, when you see big changes in the ecosystems, it's a result of more than one stressor at any one time," he said. "So the increasing temperatures are definitely one of those stressors, but if you're increasing the temperature and then also, like, increasing the amount of nutrient pollution, increasing the amount of disease in an area, you're going to, obviously, multiply those effects."

NOAA forecasts the “extreme ocean temperatures” in the southern Gulf of Mexico and Caribbean Sea are likely to continue “through at least October.”