Carib Coral Reef on Verge of Collapse

M.A. Dworkin

Caribbean Ocean - According to a new study, most coral reefs in the Caribbean and tropical western Atlantic could stop growing and even start eroding away by 2040 if global warming remains unchecked. 

Coral reefs are made up of colonies of hundreds to thousands of tiny individual corals, called polyps. These marine invertebrate animals have hard exoskeletons made of calcium carbonate, and are sessile, meaning permanently fixed in one place. Polyps grow slowly, forming different shapes and sizes depending on their species. Assisted by other animals with calcium carbonate skeletons and also coralline algae, corals form complex, three-dimensional reefs. 

These ecosystems, which protect millions of people and sustain billion-dollar industries, are on the verge of collapse within our lifetime. Reefs across the region are reaching a point where they will no longer keep pace with sea-level rise. This will affect the ability of reefs to buffer coastlines from wave energy, threatening nearshore habitats.

Coral reefs aren’t just attractive dive sites. They are living breakwaters, dampening wave energy, reducing storm damage, and creating sheltered environments for habitats like seagrass meadows that serve as fish nurseries. They offer food and shelter among their crevices and branches for animals including fishes, molluscs, sea urchins and sponges. Reefs protect valuable coastlines during cyclones and storm surges by breaking up wave energy. For the reefs to continue to act as natural wave barriers, they need to keep up with sea level rise. However, coral growth is increasingly under threat from diseases, pollution and particularly the effects of climate change. 

Rising ocean temperatures are causing reefs worldwide to bleach and die, making reefs more vulnerable to other threats. Meanwhile, higher carbon dioxide levels are making seawater more acidic, making it harder for corals to build their skeletons. 

Globally, reefs protect an estimated 5.3 million people and coastal assets worth more than $100 billion every decade.

“We have observed the progressive decline in reef health due to diseases and extreme ocean heat over the last several decades,” said Chris Perry, the study’s lead author and a Professor at the University of Exeter, U.K.

The results of the study paint a grim picture for the coral’s future. The researchers found that by 2040, more than 70% of coral reefs in the Caribbean region - including the Florida Keys, Mexico’s Caribbean coast, and the Caribbean island of Bonaire - could stop growing and start eroding. By 2100, nearly all the reefs could be eroded, if global warming reaches 3.6 degrees Fahrenheit above pre-industrial levels. Under current climate policies, temperatures globally are projected to rise by 4.86 degrees Fahrenheit by 2100. 

There is hope on the horizon. Marine Biologists claim that new approaches could help prevent species loss and retain ecosystem function. One approach that could save the reefs is Assisted Gene Flow (AGF), a powerful tool to boost coral resilience. The approach was recently approved to help save Elkhorn Corals in Florida from extinction but faces regulatory challenges in its application, due to static regulatory frameworks. The precautionary nature of such regulations, slow to change to environmental needs, poses a further roadblock to the survival of threatened corals.

Carlos Prada, an assistant Professor of Biological Sciences at the University of Rhode Island, recently co-authored an article in Science, addressing the policy aspects of coral restoration work and advocating for the use of AGF to provide corals in the region with the boost they need to survive. 

AGF involves introducing individuals, gametes, or alleles, to enhance the survival and reproductive success of species that have experienced severe declines. Though AGF has been applied in terrestrial ecosystems, it is still new in marine contexts. This managed interbreeding can boost genetic diversity and improve traits like resilience or disease resistance. 

Mr. Prada has now been joined by 14 other international coral scientists, urging regulatory reform to accelerate global coral restoration using AGF, calling it an essential step to safeguard the economic value and coastal protection that reefs provide. 

The intense marine heat wave of 2023, with ocean temperatures above 86 degrees, illustrates the urgency of using AGF to help preserve genetic diversity in the region.

Meanwhile, as regulatory agencies drag their feet on regulatory reform that will greatly aid in fighting the oncoming ravages of climate change, and beat a new path towards current environmental needs, the clock is ticking on the survival of coral reefs in the Caribbean.