Project Grows Corals to Repair Reefs

Hudson uses hollow concrete domes to host the coral, which he fastens using special glue. He installed his first transplanted reef into Florida’s waters in 1976 as an experiment. So far the 4-foot-long reef and 90 percent of his subsequent transplanted reefs have survived.

But he points out 30 years is only a blip on coral reef time scales.

“The jury’s still out on how successful planting coral will be,” he says. “Even if what you do in the first couple years may seem successful, their lifespans are really decades or centuries so what may look successful today could be gone tomorrow.”

Although Hudson doesn’t grow his own coral like businessman Lowe, other scientists have. Robert Richmond, a specialist in coral reefs at the University of Guam’s Marine Laboratory, explains there are a couple ways of cultivating coral.

Building by Breaking

One is to capture coral larvae that are spawned once or twice a year on a lunar cycle. The other is to fragment the corals. That works, he explains, because coral reefs grow through a relationship between an animal — polyps living inside the coral limestone — and algae.

The polyps exist in a thin layer of tissue over the coral’s limestone base and multiply and expand at the tips of the coral. Tiny algae, dependent on sunlight, live inside the coral’s tissue and produce nutrients that feed the polyps and help them grow. As the polyps grow, some of the polyps calcify algae and other organisms to secrete adhesives that form the reef.

Much like an inflated balloon will consume more space as it inflates, these calcium-producing polyps will grow and lay down limestone more rapidly if more coral surface is exposed by breaking.

In Guam, Richmond cultivates small amounts of corals in experiments to assess damage done to coral by pollutants and cyanide fishing. Throughout the South Pacific and Southeast Asia, he explains, fishermen occasionally drip cyanide into shallow water to stun fish, which they then capture and sell to aquariums or in some cases to restaurants that feature live fish.

By exposing homegrown coral to minute amounts of cyanide, Richmond and his colleagues have shown that the chemical is deadly for the reefs.

“We call it Dr. Doolittle science,” he says. “We’re essentially talking to the animals to hear what they need to grow and reproduce.”

While Richmond supports coral cultivation for such experiments, and for producing coral to be used in aquariums, he too is wary of planting cultivated coral as a solution to depleted reefs.

“The idea of putting corals back in the water is very sexy,” he says. “But we have to be careful not to sell people a false bill of goods. If we really want to help the problem we have to start with fixing what’s killing them.”

Sturdy Crops

But Lowe is more optimistic. He says his corals are cultivated under conditions that are designed to make them more hearty. His tank-raised corals grow in water that is 86 degrees Fahrenheit. That exceeds temperatures that coral reefs normally tolerate. Lowe argues his corals will be better at surviving in waters warmed by possible global warming.

Lowe’s first cultivated corals are scheduled to be installed into Mustique’s waters by the end of December. If the tank farm coral survives through the next year, Lowe hopes to launch his next project in Jamaica — an island dependent on its reefs for tourism.

“I have no doubt they’ll survive,” he says. “In the tank, everything you’d expect they’d die from, they’re thriving in. They should do fine.”

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