Keys to the coral kingdom: protecting Caribbean reefs

The Caribbean’s coral reefs are ecological treaures and economic assets — but they’re also in danger. Nazma Muller learns about a project in Bonaire aimed at restoring these underwater wonders

Photograph by Isabelle Kuehn/Shutterstock.comCRF Bonaire cultivates staghorn and elkhorn corals in warm, shallow waters with ample nutrients. Photograph courtesy Coral Restoration FoundationPhotograph courtesy Coral Restoration Foundation

A pinhead. Worth US$375 billion. Annually. This is the magical mathematics of coral: a microscopic organism, invisible to the naked eye, creates the massive, complex structures known as coral reefs. Worldwide, reefs are responsible for providing US$375 billion a year in goods and services to the planet, according to a Global Coral Reef Monitoring Network report. In the Florida Keys alone, reefs generate about US$1.2 billion annually from tourism (diving tours, hotel accommodation, restaurants, and other businesses).

On its own, the coral polyp is a fragile speck, spineless and colourless. (It is, after all, a cousin to the anemone and the jellyfish.) But when a polyp bounces up with zooxanthellae — the scientific name for several species of photosynthetic yellow-green algae — they create pure magic. “Zoox” are just as microscopic and deceptively simple in appearance as the coral polyp, but when these colourful algae move into a polyp, setting up shop in its skin, they rock the marine world. Literally.

Together, polyps and zooxanthellae create the sprawling, psychedelic marine metropolises that are reefs. The zoox are like dream tenants for the polyps, bringing life and colour to the party: they light up the otherwise colourless bodies of the polyps in the most intense psychedelic hues of purple, pink, red, orange, and yellow. It’s a mutually beneficial relationship: the coral provides the algae with a protected environment, and compounds that they need for photosynthesis, which the zoox dutifully convert into oxygen and glucose, glycerol and amino acids. The polyp uses these products to make proteins, fats, and carbohydrates, and to produce calcium carbonate, which it secretes as an exoskeleton. These hard shells are the building blocks of coral. As polyps die, they leave behind their shells, creating layers upon layers of complex coral “skyscrapers,” upon which new colonies with millions of polyps thrive.

These underwater megacities are just like New York or Tokyo, teeming with millions of inhabitants attracted by the “bright lights” and tons of food to be had. As every child who has seen the movie Finding Nemo knows, coral reefs are where all manner of marine life — from clownfish to sea turtles — meet, mate, set up residence, go grocery shopping, and hide from gangs of big, bad predators. In addition to being protective barriers for Caribbean coastlines, the many cracks and crevices of reefs are nurseries for massive schools of fish, shrimp, lobsters, oysters, and clams.

Also, like rainforests on shore, reefs are yielding amazing chemical compounds with a mind-boggling array of uses. The incredible chemistry that happens within a reef ecosystem has already resulted in AZT, a treatment for HIV (an analysis of the chemicals from a Caribbean sponge provided vital clues to make the drug). Reef-related research has been used in treatments for cardiovascular diseases, leukemia, and skin cancer as well.

Unfortunately, many of the Caribbean’s reefs have either been killed off or are dying, from contamination of the oceans, human activity — like the building of piers and docks on top of them, careless divers who kick them or drop anchors on them, pesticide runoff, or sewage from hotels and coastal developments — and global warming. As the oceans heat up, the coral polyps become stressed by the change in temperature or UV radiation, and they expel the zoox, which causes them to lose their gorgeous colour — and their source of oxygen and nutrition. Since the 1980s, a host of diseases, “bleaching events,” loss of sea urchins (which eat coral predators), deteriorating water quality, and overfishing have affected coral populations throughout the Caribbean.

But there is hope that some of the region’s reefs can be resurrected, through the simple but groundbreaking concept of coral nurseries: the cultivation of new corals, in protected locations, to restore damaged reefs. The Coral Restoration Foundation (CRF), a non-profit conservation organisation based in Florida, founded by environmentalist Ken Nedimyer, is a pioneer of such efforts.

CRF, aware that most reefs are located off the coasts of developing countries, has developed a range of simple, low-cost coral aquaculture techniques that use thin wires or fishing lines, concrete blocks, steel rebar rods, PVC pipes, and heavy-duty cable ties to propagate staghorn and elkhorn coral. Both are important reef-building corals, structurally complex with many large branches. Elkhorn coral colonies have an average growth rate of two to four inches a year, and can eventually grow up to twelve feet in diameter, while staghorn corals can add as much as eight inches to their branches in one year.

Eventually, CRF’s propagation efforts in the Florida Keys caught the attention of environmentalists elsewhere in the Caribbean. In 2012, Nedimyer was invited by Buddy Dive Resort in Bonaire to help with preserving the Dutch island’s greatest asset: its reefs. Out of this visit, Coral Restoration Foundation Bonaire was born.

First the CRF Bonaire team, including local divers and scientists, identified specific sites for the nurseries and reef out-plantings. Next they collected three hundred fragments of different genetic strains of staghorn and elkhorn coral, which were used to populate coral growing-trees in two nurseries off the coast of Bonaire and Klein Bonaire (an uninhabited islet west of the main island).

Throughout 2013, the CRF Bonaire team cultivated the corals, planting them on line, disk, and tree nurseries in locations where the staghorn and elkhorn would thrive: shallow, warm waters with lots of nutrients. These corals are constantly monitored and cleaned, since they form the base nursery stock, which is fragmented every six months to develop second- and third-generation corals.

Now there are more than five thousand coral fragments growing in the nurseries off Bonaire and Klein Bonaire, and almost a thousand have been replanted in the reefs. “We’re very fortunate to be working with CRF, and to be able to combine our efforts to preserve the current genetic diversity of our staghorn and elkhorn corals,” said Anja Romeijnders, president of Tourism Corporation Bonaire, at the launch of the project. “Given the fact that Bonaire is world-renowned for having some of the healthiest reefs in the Caribbean, it’s the ideal place for this project to prosper, and in turn encourage other islands to follow suit. Coral restoration is a very important part of revitalising the marine environment, and we are proud to be taking the first steps towards accomplishing this task.”

The second phase of the Bonaire programme — outreach, training, and capacity-building — has already taken off, with Buddy Dive Resort instructors training volunteer divers to help maintain and expand the nurseries. In November 2013, the very first PADI Coral Restoration Divers were certified after they transplanted their own little coral branches from a nursery to the reef. Over the next few years, these replanted corals will grow and spawn new colonies.

It is, in some ways, like the rebuilding of a sacked Rome. But nonetheless there is hope that, with patience, the damaged coral kingdoms of the Caribbean will be rebuilt — one polyp at a time.