A Micro-Step Toward Reef Restoration

As in any reproductive clinic, the new life growing in a makeshift laboratory here is the result of successful synergy between science and nature.

But these test-tube babies are corals, nurtured in the kitchen of a rented condo as part of a National Oceanic and Atmospheric Administration project aimed at restoring the severely damaged Molasses Reef.

These babies face a more perilous and protracted path to adulthood than do their human counterparts, confronted by everything from hurricanes and global warming to disease and pollution.

Hurricane season coincides with the few nights each year when the diminishing numbers of adult corals in the Caribbean release their spawn. Before they can cross-fertilize, many of the egg-sperm bundles are dispersed by heavy wind and waves, hampering conception.

The survival rate of corals is “miserably low,” said Margaret Miller, an ecologist overseeing the NOAA project.

To boost reproduction, she and her team ventured out by motorboat in the dead of night in late August, the brief nocturnal spawning season for the endangered elkhorn coral. Using buckets, they scooped up slimy bundles from the ocean surface and mixed them for mating, then rushed the embryos to the lab, where they could develop in a calmer environment of saltwater-filled coolers and beakers.

Settled onto ceramic shards that simulate a reef’s limestone foundation, the still-microscopic larvae were taken back out to sea early this month and positioned on the rebuilt reef, where researchers hope they will attach themselves and grow.

Molasses Reef, one of most beautiful and heavily visited sites in the Florida Keys, suffered devastating damage in 1984, when the Cypriot-registered container ship Wellwood ran aground there. The vessel’s crew first attempted to power off the reef, then tugboats tried to drag the ship to deeper water, mowing off the corals and gouging the reef’s foundation. The grounding destroyed 62,000 square feet of living coral and injured 807,000 square feet of reef habitat.

Part of a $6.3-million insurance settlement paid by the Wellwood’s owners became available to NOAA in the late 1990s. Repairs to the reef’s foundation were made early this decade, then efforts to create new coral life got underway in 2003.

Miller and her colleagues attempted the lab cultivation after the 2004 and ’05 spawning seasons, but all but a few of the babies were wiped out within a month of being deposited. The researchers blame catastrophic storms that swept through the Straits of Florida for disturbing the larvae before they could adhere securely, although they say other factors might have contributed.

“We know so little about coral larvae in the field -- it’s just impossible to study them there,” Miller said of the research effort begun less than two decades ago.

Alina Szmant, a University of North Carolina biology professor and pioneer in the nascent art of coral breeding, is at work on a coral-settlement-mortality study in Puerto Rico with a grant from the Environmental Protection Agency.

She attributes the previous failures to cultivate coral at least in part to the rising temperature of ocean waters. She tested larvae survival at four water temperatures in the lab and found a clear correlation between warmer water and higher death rates.

“I can chill my water for the experiments, but you can’t chill the ocean,” Szmant said, citing a two-degree rise in sea temperatures since the 1980s. “Of course we hope we’re going to improve things with what we are doing. But we’re putting Band-Aids on a dike that is breaking open.”

Harold Hudson, reef restoration specialist with the Florida Keys National Marine Sanctuary here, is less pessimistic about the prospects for re-creating the diverse marine life that existed on Molasses before the Wellwood grounding. But it will take generations, he said.

“Reefs are complex geological features, and we just don’t live long enough to study them,” said Hudson, who designed and installed the ersatz reef modules now filling in the gouges left by the ship.

He believes coral growth is being inhibited by other changes in the biodiversity of the Caribbean. Long-spined sea urchins used to perform a cleansing function that left the reef foundations free of algae and more conducive to coral attachment, he said. But a water-borne virus wiped them out in the mid-1980s.

“That event in itself shifted reef ecology to a point where now macro-algae have the advantage over hard corals. They’re fast-growing and quickly come in and dominate an area where urchins were feeding,” Hudson said. “They’re the weeds of the reef.”

In the early 1980s, vast quantities of elkhorn and staghorn corals died of disease caused by a naturally occurring organism that ate the large framework corals’ tissue, Hudson said.

River-borne pollutants flowing into the Caribbean also clog reefs and deter larvae adhesion.

Szmant said incidents of “bleaching” -- the loss of coral pigment when the symbiotic relationship between coral and unicellular algae breaks down -- have coincided with the warmest years on record and taken a further toll, killing more than half the framework corals in the region in the last 15 years.

Hoping to boost the number of survivors this year, Miller ramped up the number of larvae. More than 150,000 brain coral cultures and 12,000 elkhorn were deposited directly onto the reef after fertilization, and about 2,000 of each species were nurtured in the lab and moved to the reef a week later.

Miller’s babies were still in the lab when Tropical Storm Ernesto blew by in late August, and they haven’t been disturbed by weather since returning to the reef. Survivors will remain too small to be seen with the naked eye for months, but Miller expects to reexamine a few pieces of the reef rubble in a month or two to check the numbers.

Coral growth is painfully slow, researchers say. The relatively fast-growing elkhorn can’t be seen by divers for six months. To grow to full size -- as large as a room for some species -- coral must live for decades.

Even if the effort to repopulate Molasses Reef succeeds, Miller says, the fate of Caribbean coral is precarious and the strategy of human intercession to enhance its fertility flawed.

“If a species is dependent on us for reproduction, that’s trouble,” she said. “And it isn’t an effective restoration means at this point. What we have accomplished is only baby steps.”

carol.williams@latimes.com