Editorial Team
Publication Date
November 6, 2024
Gabriela Meléndez Rivera, GPJ Puerto Rico
An elkhorn coral close to shore at El Eco, Vega Baja, Puerto Rico.
VEGA BAJA, PUERTO RICO — Ricardo Laureano suspected there was something special about the elkhorn corals in the El Eco reef, in northern Puerto Rico. In his 16 years of protecting and monitoring their growth, the coral worker, as he describes himself, has seen few cases of bleaching, a problem that increasingly ravages corals globally. Scientific findings have proven Laureano right. The reef he protects is key to combating the effects of climate change on the archipelago.
A 2024 study in marine and environmental archaeology suggests that the El Eco reef has survived since pre-Hispanic times, potentially due to a genetic variation that makes the coral resistant to bleaching. Bleaching occurs when rising water temperatures force corals to expel photosynthesizing algae, leaving reefs a ghostly white. Local scientists now believe that El Eco’s corals could help repopulate bleached reefs — and mitigate against other climate-related disasters.
“It’s Puerto Rico’s latest gem for coral conservation,” says Edwin Hernández, senior scientist at the Marine Environment Society, an organization dedicated to reef restoration in Puerto Rico.
At first glance, the elkhorn coral looks like an underwater hand reaching for the sky. One of the most important corals in the Caribbean, it provides habitat for many species, and its rapid growth and location on the reef allow it to withstand wave impact. The species has been listed as “threatened” under the United States’ Endangered Species Act since 2006, and as global temperatures rise, its populations are at greater risk than in the past. It withstands bleaching better than other species and is showing signs of branching out and resisting higher temperatures, but can’t entirely outpace it.
In 2023, the Caribbean recorded its worst coral bleaching mortality since 1987. By October, mass bleaching affected over 95% of Puerto Rico’s corals, in what the Marine Environment Society’s technical reports described as an “unprecedented” marine heat event.
Hernández says all elkhorn colonies died in Cabo Rojo, on the southwest coast of the archipelago. Only sporadic populations survived in other areas. But in Vega Baja, he says, home to El Eco reef, coral mortality was only 1.7%.
Climate anomaly
Mariela Declet, a marine biologist and environmental archaeologist, turns to history to explain the resilience of the El Eco corals. Through zooarchaeological analyses, which study animal bone remains, Declet found that, centuries ago, this coral survived temperatures similar to today’s.
Between 800 and 1300 A.D., the northern hemisphere saw temperature changes and a high incidence of hurricanes. Evidence points to a massive coral bleaching event between 900 and 1000, which affected Puerto Rico’s north and south coasts. But, as Declet describes in her University of California doctoral dissertation, the El Eco corals managed to adapt and survive.
Between 2008 and 2019, around 14% of global reefs were lost to bleaching. If no protective measures are taken, scientists predict that 99% of these ecosystems could disappear by the end of the century. This would mean a loss of habitat for 25% of known marine species, the collapse of the fishing industry, and greater coastal exposure to the ocean’s force.
Worldwide, nearly 200 million people depend on coral reefs to protect them from storm surges and waves, as these ecosystems can reduce wave energy by 97% and decrease wave height by 84%.
Every year in the United States alone, coral reefs protect an estimated 18,000 people from flooding and prevent around 825 million US dollars in damage, according to a 2019 United States Geological Survey study. The same document indicates that Puerto Rico’s main island would face the most extensive flooding in US territory if it weren’t for coral reefs.
For Declet, the resilience of elkhorn corals in El Eco offers “a sense of hope” for the conservation and reproduction of the species.
In 2023, Vegabajeños Impulsando Desarrollo Ambiental Sustentable (VIDAS), a volunteer organization that Laureano leads, transplanted some of the El Eco corals to El Escambrón beach in San Juan. Hernández, who has monitored the area, says the specimens have begun to branch out and show resistance to high temperatures.
This exercise could be replicated in other areas of Puerto Rico’s capital to prevent flooding. In 2023, the Federal Emergency Management Agency approved 3 million dollars under the Hazard Mitigation Grant Program for the first phase of reef restoration off the coast of San Juan. Nilda Jiménez, endangered species program coordinator at Puerto Rico’s Department of Natural and Environmental Resources, says the department is considering El Eco corals for the project.
But scientists acknowledge that with the rapid increase in ocean temperatures, success is not guaranteed. “At this rate,” Declet says, “we don’t know what will survive and what won’t.”
In October, El Eco faced a bleaching event due to high water temperatures, Hernández says. According to his preliminary estimates, about 5% of the coral population has died.
Protecting reefs
Although the El Eco corals are resilient, it doesn’t mean they always will be, Jiménez warns. She believes it’s necessary to continue identifying resistant coral colonies and focus on reef protection.
A 2022 study by Rutgers University, the Coral Reef Alliance and other institutions concludes that preventing water pollution, avoiding overfishing, and eliminating other risk factors will help resilient strains develop and repopulate other reefs.
In August of this year, Puerto Rico’s government signed a law that declared El Eco reef part of the Vega Baja and Manatí Submarine Gardens Natural Reserve. The measure guarantees 1 million dollars in annual funding to preserve the elkhorn coral and other species. Laureano, from VIDAS, also aspires to promote genetic variability studies and monitor water quality and temperature, among other initiatives to prevent the reef’s deterioration.
José Antonio Vargas, the senator who introduced the law to protect the reef, told Global Press Journal that the reserve’s designation will allow “a special level of care” for the elkhorn coral.
Meanwhile, Laureano, along with other Vega Baja volunteers, still works to protect the reef. Now that he knows why the corals he has cared for over the years are so resilient, he has doubled his efforts.
“I don’t think we hold the copyright for Vega Baja’s super corals,” he says. “It would be nice to help more people.”
Gabriela Meléndez Rivera is a Global Press Journal associate reporter based in Vega Baja, Puerto Rico.
