In 2023, Florida saw record-breaking ocean temperatures, alarming scientists and causing severe damage to the state’s coral reefs. And even though it’s only spring, waters are warming up.
“As far as sea surface temperatures go, which is kind of the skin temperature of the ocean, that started breaking records in March last year. And it's been breaking records every day since,” Brian McNoldy, a senior research associate at the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science, said Friday on The Florida Roundup.
“There's another metric or quantity that we look at called ocean heat content. So that's more of how much energy is in the ocean through a depth, so not just at the skin. And that's been breaking records now since May, I believe it was.”
McNoldy said there isn’t a consensus on why waters are warming at their current rate. But there are a lot of factors at play, such as El Niño and La Niña. He said there’s also less Saharan dust blowing off the African continent and less ship tracks, causing the ocean to intercept more of the sun’s energy. And there’s less winds blowing across the Atlantic Ocean due to a weaker-than-normal high pressure system over the subtropical Atlantic.
“Months prior to when we would typically expect something like that, we had the Florida Keys sounding the alarm, where they were seeing mass bleaching and entire coral nurseries lost. And we didn't think that was possible.”Dalton Hesley, senior research associate at the University of Miami Rosenstiel School
As for hurricanes, McNoldy explained the effect warmer waters could have on storm season.
“What these anomalies do is they can help extend hurricane season, so we might see some activity prior to the official start of the season, we might see activity outside of where we typically would at the beginning of the season," McNoldy said. "Just because when the rest of the conditions come into play, the part of the ocean that can maintain a hurricane is a much larger area than it would normally be.”
Coral reefs are also impacted by the high temperatures, as scientists saw in 2023.
“So those temperatures started climbing in the spring and by July, they were on average about 4 and a half to 5 degrees hotter and went on for days. That prolonged heat caused the coral to bleach and bleach very quickly,” Jenny Staletovich, environmental editor for WLRN, said on The Florida Roundup. “I think scientists were watching this sort of unfold on ramped-up time. It alarmed a lot of people.”
Dalton Hesley, a senior research associate at the University of Miami Rosenstiel School, witnessed the coral bleaching in action. Hesley works at Dr. Diego Lirman's Benthic Ecology and Coral Reef Restoration Lab at the school.
“Months prior to when we would typically expect something like that, we had the Florida Keys sounding the alarm, where they were seeing mass bleaching and entire coral nurseries lost. And we didn't think that was possible,” Hesley said on The Florida Roundup.
“We had to act very quickly and launch capacity resources, team members to try to essentially move as many corals as possible from offshore, potentially in harm's way on to these land-based nurseries and resources.”
While corals in the Keys were most impacted by the high temperatures, Hesley said Miami-Dade County was largely spared. He also noted corals can recover from bleaching once conditions return to normal.
As scientists continue to restore coral reefs across Florida, Hesley said public support and community participation is important. He manages Rescue a Reef, a citizen science program at UM centered around coral research and restoration.
“That's obviously having a positive impact ecologically, rebuilding our coral reefs," Hesley said. "But we think the experiential, educational benefits are equally important, because we really want people to understand just how important our coral reefs really are to them, their loved ones, committee members, and what they can do about it.”
