‘Ecological emergency’ grips Florida coral reef

By E.A. Crunden | 08/21/2023 01:24 PM EDT

A massive marine heat wave has hit the ocean waters around the Sunshine State, sparking panic among coral experts and advocates.

A fish swims near coral showing signs of bleaching at Cheeca Rocks.

A fish swims near coral showing signs of bleaching at Cheeca Rocks off Islamorada, Fla., on July 23. Andrew Ibarra/NOAA via AP

Skyrocketing temperatures on land and at sea are imperiling the country’s only coral barrier reef, leaving scientists and experts increasingly alarmed.

Heat around southern Florida has created a disaster scenario for coral, which provides a key source of shelter for marine species while also mitigating storm impacts on land. As water temperatures have neared 100 degrees Fahrenheit, reefs are experiencing unprecedented bleaching events.

That situation escalated earlier this month. Scientists sounded the alarm after assessing Cheeca Rocks, home to some of the highest coral coverage in the Florida Keys.


“Just awful news,” NOAA reported back. “The reef at Cheeca Rocks in Florida is completely bleached.”

Experts from the U.S. Geological Survey similarly highlighted the mounting problems late last month, citing images of bleached and dying coral off the South Florida coast. Lauren Toth, a USGS research physical scientist and coral expert, said that the images captured in mid-July were especially jarring due to their timing.

“What’s most concerning about this bleaching is the fact it’s happening much sooner in the season than what’s normal,” Toth said. “We typically see bleaching events toward the end of summer.”

The dire situation has sparked panic. Ocean temperatures have surged, with a buoy in the Florida Bay hitting 101.1 degrees at a depth of 5 feet in late July. That temperature was not recorded in an area where reefs are abundant, but other parts of the water are also hitting over 96 degrees in some places.

Water in the Gulf of Mexico, along with the rest of the ocean bordering South Florida, is normally warm. But readings are typically in the mid-80s, and any sharp spikes above that can be greatly damaging for marine life. NOAA experts noted in late July that the southern Florida Keys are currently experiencing their hottest water temperatures ever documented since the satellite record began in 1985.

Laying out how grim the situation is becoming, Derek Manzello, who coordinates NOAA’s Coral Reef Watch, explained that high temperatures become more of a concern the longer they go on.

“If the heat stress does not subside, the coral will die,” he said.

‘Incredibly important’

Coral reefs are deeply important, due in no small part to their vital role within the broader marine ecosystem.

They are marine invertebrates that work in a symbiotic relationship with algae, which helps feed them through photosynthesis as the latter converts sunlight into energy. Along with algae, coral also serve as tree-like dwellings for a number of life forms, offering protection and shelter for creatures like shrimp, conch and lobsters.

They similarly function as an economic engine, helping to power seafood production, along with tourism. Coastal states like Florida rely on water as a chief draw for visitors eager to explore beaches and offshore wonders.

But reefs are also necessary in the midst of worsening climate impacts. Found relatively close to shore, they can act as mountains, breaking up waves before they reach the coastline. With healthy coral in place, waves can be largely kept in check during surge events, shielding land areas from the brunt of storms, as well as erosion.

Cindy Lewis, director of the Florida Institute of Oceanography’s Keys Marine Laboratory, called coral “the rainforests of the ocean,” adding that they serve an “incredibly important” role in their environment.

When they weaken and die, however, there is little in place to offer protection. Andrea Treece, a senior attorney for the nonprofit group Earthjustice, assessed the situation as an “ecological emergency,” one that is endangering the continent’s only barrier reef.

“The Florida Reef Tract has already shrunk dramatically due to disease and climate change that’s causing ocean acidification and killing corals outright,” noted Treece. “The corals also face threats from overfishing and coastal development.”

Threats to coral have long been a crisis in countries like Australia, whose Great Barrier Reef is under constant strain from climate change. But Florida’s worsening situation is starting to draw attention as the wider United States grapples with a sweltering summer.

When the water is too hot, coral expel algae, losing access to a key source of food. Bleaching does not immediately kill coral, but it does put them in a perilous position if the problem is sustained. Those weakened by bleaching events are even more susceptible to what comes next if the situation is not rectified: starvation.

Typically, coral can avoid that fate as seasons change. But massive heat events are making that less likely.

“The cooler water temperatures in the fall can help coral survive late summer bleaching,” Toth of USGS said. “However, with this bleaching occurring almost two months before what’s typical, it’s unlikely some of these coral will be able to survive unless the waters cool off soon.”

Rescue efforts

To save coral, scientists have been pulling some species and taking them to land where they can exist in cooler temperatures for the time being.

That includes coral species like staghorn and elkhorn, both of which are considered threatened under the Endangered Species Act. The coral are being taken to places like the Keys Marine Lab, where experts are doing their best to save them from dying. A chief goal is keeping those species from going extinct in Florida, while also learning which types of coral are more resilient against warming temperatures.

But the implications of the current coral bleaching and dying event playing out is weighing heavily on scientists, who have repeatedly noted that the early nature of the heat events is alarming. They also worry that the problem could worsen. NOAA offers a weekly coral bleaching heat stress outlook, with last week’s at 90 percent probability. Most of southern Florida is facing an alert level where bleaching is expected, a trajectory expected to worsen by September.

“They’re literally sitting, stewing in the water out there in these hot, hot temperatures,” said Lewis of the Keys Marine Lab.

Scientists have warned that the scenario playing out is not an anomaly but a glimpse of the unfolding reality as climate impacts worsen. Earthjustice’s Treece highlighted the grim landscape underpinning the situation.

“We’ve heated the planet to the point where the only way to save some corals is to take them out of the ocean,” she said. “In an era filled with climate wakeup calls — wildfires, flooding, droughts — this one still leaves me reeling.”

The Associated Press contributed.