Scientists Speed Coral Growth
St. Louis sits hundreds of miles from the nearest natural coral, and it's on the other side of the world from the most famous coral reef. Yet the key to saving this crucial oceanic organism just might have sprung from the muddy banks of the Mississippi.
By exposing embryonic coral cells to concentrated salt water, researchers at St. Louis' World Aquarium have been able to accelerate coral's growth, which is notoriously sluggish.
"With this rate of growth, we think coral reef growth can be dramatically altered across the planet," said Leonard Sonnenschein, president of and a researcher at the World Aquarium. He first successfully applied this technique to clams, clown fish and shrimp.
Philippe Cousteau, president of the environmental advocacy group EarthEcho International, said growing coral in captivity is "very cutting-edge stuff . . . there are only a few people doing it."
Coral reefs, including Australia's noted Great Barrier Reef, sustain much of the world's tropical-sea ecology. Reefs not only house a third of all marine species, but also anchor soil to prevent underwater erosion and produce algae that form the base of oceanic food pyramids. Coastal development, increased pollution in rivers that empty into oceans and commercial activities such as fishing and snorkeling have endangered more than three-fourths of the world's coral reefs, ecologists estimate. This has spurred worldwide efforts to preserve them.
Or better, regrow them, which is where Sonnenschein's patented process steps in. First, he submerges coral stem cells in a plastic bag with concentrated salt water, which he compares to a slap in the cellular face. The salinity is not much greater than that of seawater -- about the amount of salt added to a margarita. But to cells, this extra pinch is a nasty shock.
To counteract it, they go into overdrive. It's similar to blood rushing to someone's face after the unpleasant stimulus of a slap.
The innovation is what happens next. When the coral cells are placed in a tank of normal seawater, instead of relaxing, they retain high metabolic activity as they mature. Sonnenschein compares this to a series of light pats on the cheek, to keep the color up.
Research intern Elizabeth Smith pointed out that the treated coral, underneath the hermit crabs and snails that scour and clean them, burgeon and bloom more fully than untreated counterparts.
Ideally, scientists will nurse the coral -- which comes in three styles: hard, soft and "leather"- in the lab before transferring them to existing reefs. David Vaughan, executive director of coral reef research for Mote Marine Laboratory in Florida, said any rehabilitation projects would occur in three steps.
First, scientists must form a "gene bank" for endangered coral. "It's like how a zoo is a bank for threatened species," he said.
Next, scientists would propagate the coral in the lab. Some species of coral grow only a millimeter per year, and even quick sprouters add less than an inch. Vaughan said it's like a forest growing in slow motion. Sonnenschein's process could facilitate this phase.
The third step, transferring the coral to living reefs, is the trickiest, Vaughan said. He noted that corals are sensitive to light conditions and water temperature, and that even in perfect environments corals compete with each other.
"Even if a process works in the tank . . . when that coral is out there in the field, there might be other components such as the toxins" that prevent the coral from succeeding in the wild, he said. Corals can poison related species the same way that pine trees kill off plants unlucky enough to sprout beneath them.
Cousteau echoed Vaughan's caveats. Although "very excited" about the results, "it is still to be proven on a mass scale." Before any potential field work begins, the World Aquarium researchers must finish analyzing current data and then optimize the technique for different species.
Sonnenschein pointed out a natural experiment that parallels his work, indicating that he may be on the right track. The Great Salt Lake in Utah, once part of a primeval ocean and now marooned inland, evaporates a little every year. As this happens, it grows saltier and saltier.
Yet brine shrimp, for instance, "not only survive, they thrive" in this hypersaline environment, he said.
Sonnenschein started a company, GroFish LLC, to help introduce his big, bulky crustaceans and fish into commercial fisheries. In addition, he and Vaughan have grown aqua fauna for commercial aquariums. He seems most excited, though, about coral.
Interestingly, the growth induced by simple saltwater mimics that of externally applied hormones. Hormones can cause defects in developing organisms, such as tadpoles.
"Can you tell the difference between a hormonal and a nonhormonal animal? The answer to that question is no," Sonnenschein said.
"We don't believe in hormonal treatments," he said. Sodium chloride suffices.
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Source: Knight Ridder/Tribune Business News