Off Miami’s coast, a possible solution for threatened coral reef

MIAMI — Consider the circumstances of diving 45 feet into a treacherous shipping channel where massive cruise and cargo ships pass on their to way one of the United States’ busiest ports.

“Diving in Government Cut is such an intimidating, dangerous type of dive, with a strong current and high turbidity," said Colin Foord, a co-founder of Coral Morphologic, a multimedia coral laboratory in Miami. “If you’re not holding on to the lock, you’re going to get sucked into the propellers of one these cargo ships.”

Foord is not an extreme diver, but he is an extreme lover of corals.

Several years ago, he discovered a rare colony of corals close to the surface in Government Cut, Miami’s shipping channel connecting the Atlantic Ocean to Biscayne Bay. It was a hybrid of staghorn and elkhorn corals, two federally protected threatened species.

“What’s so interesting is that from my perspective, it’s displaying hybrid vigor, meaning that it’s more resilient and stronger than its parents,” Foord said.

The Nature Conservancy has teamed with a consortium of entities and is heading up the largest coral restoration project in the world by expanding coral nurseries throughout Florida Reef Tract, plus the Virgin Islands.

“We’ve got six nurseries where were growing coral and a multitude of restoration sites where we plant the coral out to bring back the reef structure,” said Chris Bergh, South Florida conservation director for the Nature Conservancy.

One of those large sites is off the coast of Fort Lauderdale. The Nature Conservancy, the Nova Southeastern University (NSU) Center of Excellence for Coral Reef Ecosystems Research and the National Oceanic and Atmospheric Administration have grown nearly 3,000 colonies of staghorn corals since the project began in 2008.

“These are fast-growing coral, which grow about three to five centimeters a year,” said David Gilliam, an NSU research scientist. “So in a year we have enough material to outplant the larger fragments. This helps the species recover, and they provide habitat, which is very important.”

Farther south, all along the Florida Keys, citizen-scientists are diving and planting thousands of staghorn and elkhorn colonies in the Florida Keys National Marine Sanctuary. The coral may be fast-growing, but officials in Florida have been trying to speed up the process by building artificial reefs.

“In the ’80s and ’90s, there was never enough recreational dive opportunities, so we were building artificial reefs to take pressure off natural reefs,” said Ben Mostkoff, who was the artificial-reef coordinator for the Department of Environmental Resources of Miami-Dade County for two decades.

Artificial reefs are made of durable, stable and environmentally safe materials like steel or concrete and are placed on the ocean bottom to attract floating baby coral, or polyps, to settle and multiply. Now more than 28 artificial reef sites — including nearly 50 large vessels, two retired oil-production platforms and thousands of tons of concrete materials — dot the 35 nautical miles off the coast of Miami.

Mostkoff holds a patent for a reef-building unit that is made of concrete and rubber chips from tires in the shape of tetrahedron. Despite studies that found that the tetrahedron reef builder was extremely effective and economical, it didn’t catch on.

“It befuddles me,” he said. “Just because you build a better mousetrap doesn’t mean anyone is going to use it.”

Part of the problem is that the rubber had a stigma attached to it, which harkened to the days of an environmental disaster that began with good intentions.

Nearly 2 million scummy rubber tires are tossing around on the ocean floor about two miles off Fort Lauderdale’s coast. In the 1970s, environmentalists and government officials devised a plan to repurpose discarded tires that were piling up in landfills by tossing them in the ocean to serve as a giant artificial reef. But that was before scientists realized coral didn’t grow on rubber. Since then, the metal bindings that held the tires in place have rusted off, and with the ebbs and flow of the currents, the loose tires are crashing into the natural reef.

This summer the Florida Department of Environmental Protection plans to have a contractor remove about 368,000 tires from the area closest to the shore, where the tires pose the most significant threat of damage to the reef. But more than 1 million tires remain, and it’s uncertain if they will ever be removed.

It has been an unusually warm winter in South Florida, and the latest federal study reports that coral reefs may be able to adapt to moderate climate warming. The big question with all these efforts to restore coral reefs is, will it be enough to offset the impact of worldwide stressors that that are decimating coral populations?

“I think these corals in Miami are the most important to study on the planet because most research looks at sick coral in a healthy environment,” Foord said. “We need to understand how this coral is evolving and, by doing so, we can unravel the clues for how corals adapt in today’s modern world that interfaces with man and industry.”

This story has been updated to correct the agency planning to remove rubber tires from the ocean floor this summer.