Scientists found that a high temperature of seawater has caused significant damage to over 75% of human-grown coral in the Florida Keys. This was part of an attempt to protect a species at risk due to climate change.

Scientists from the National Oceanic and Atmospheric Administration revisited five reefs this week to assess the survival of staghorn and elkhorn coral, which are considered endangered species. They were interested in how these repopulated organisms fared during the summer and fall, when water temperatures reached the 90s (30s Celsius) for an extended period of time. Unfortunately, the majority did not survive, as there was widespread mortality among both the repopulated and wild coral on the five Florida Keys reefs.

Researchers attribute the rise in water temperature, exacerbated by a natural El Nino event, to human-induced climate change as the main cause of the distressing conditions for the fragile coral, which are living organisms. Following attempts to save the coral during last summer’s heat wave, scientists have now examined the results of their first winter assessment to determine which coral managed to survive.

According to NOAA, only a small percentage of the 1,500 staghorn coral and 1,000 elkhorn coral that were surveyed were still alive. At Looe Key, the most southern reef studied, no live wild or replanted elkhorn or staghorn coral was found, as stated by coral biologist Katey Lesneski, who is also the research and monitoring coordinator for NOAA’s Mission: Iconic Reefs.

“It is extremely distressing to see,” Lesneski expressed in an interview only two days after the dives were completed. “In addition to considering the economic and environmental advantages that reefs and corals offer, there is also the loss of their inherent beauty that draws many people to the Keys for sightseeing and experiences. Witnessing this loss is also very disheartening.”

According to Lesneski, there is still a significant amount of data that needs to be gathered in order to fully comprehend the complete consequences. However, it is certain that nothing of this magnitude has been documented in the history of humanity.

Typically, these are corals that display strong hues of red, orange, tan, and brown. However, during their dive, Lesneski and other researchers observed dead corals covered in dull, green-brown algae which gave the appearance of being lifeless and unappealing.

The populations of staghorn and elkhorn corals are not only decreasing to the point of being listed as endangered, but they also play a vital role in the diverse coral community. According to Lesneski, these species act as framework builders, creating the essential structure for coral habitats.

Despite the fact that the scientists were underwater to inspect the human-installed coral at Horseshoe Reef, the second most northern reef they observed, Lesneski also observed an area that was once a natural colony of elkhorn coral that had been in existence for over a century.

Lesneski observed the colonies in June and noted that they were thriving. However, in July, the effects of heat stress began to take its toll and they were starting to deteriorate. As of now, there are no signs of living tissue on any of the wild colonies at Horseshoe Reef, which was devastating for Lesneski to witness.

During their exploration of five reefs, the team observed some live and healthy wild coral, according to Lesneski. However, she noted that brain or boulder coral appeared to be faring better, despite still experiencing significant amounts of death.

The collaborative effort between the federal government and private sector intends to allocate a minimum of $97 million to relocate coral species that have been cultivated on land or in ocean nurseries to seven designated locations. According to Lesneski, some of these species are identical to those already present in the water, but have suffered damage from rising sea temperatures. However, certain species have been genetically modified to be more resilient. Lesneski stated that it is currently too soon to determine if the stronger coral fared better.

According to Lesneski, NOAA recorded the water temperature at the planting sites to be 93 degrees (34 degrees Celsius), with one location reaching 94 degrees. She and others believe this temperature is too high.

According to Mark Eakin, the former head of coral monitoring at NOAA and current corresponding secretary for the International Coral Reef Society, the events of 2023 were incredibly destructive. He stated that temperatures were recorded at levels previously thought to be impossible.

According to Eakin, although the Caribbean coral reefs suffered greatly from the unusually warm water temperatures last year, the overall impact on the rest of the world in 2023 was not as severe as initially anticipated.

In response to the increasing impact of climate change, NOAA recently updated its coral reef watch alert system to include additional levels of heat stress. This is comparable to the addition of a Category 6 for hurricanes, according to Lesneski.

Both Eakin and Julia Baum, a coral biologist at the University of Victoria, expressed valid worries about attempting to restore coral reefs by reintroducing them into water that is becoming too warm.

According to Baum, attempting to restore coral in the face of climate change is highly unlikely to succeed. He likened the task to trying to redecorate a burning house, given the current state of our warming oceans.

According to Baum, the rising temperatures caused by climate change have made our oceans too warm for corals, putting them at risk. This trend is only expected to worsen.

Lesneski acknowledged the concern and stated that researchers are currently exploring potential solutions for breeding more heat-resistant coral.

According to Lesneski, it is not a simple solution. To see real change, there must be a decrease in greenhouse gas emissions from fossil fuels on a global scale and significant policy changes. However, if we want to see the positive impacts of reefs on our economy and environment, we must make efforts to conserve, act as responsible caretakers, and restore them as much as possible.

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You can find Seth Borenstein on X by searching for @borenbears.

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Source: wral.com