This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
In a delicate operation at sea, 28 healthy laboratory-raised staghorn coral colonies were transplanted last month by our Nova Southeastern University Oceanographic Center researchers to a threatened reef off the Fort Lauderdale coast. This will – we expect – initiate a restoration process for a formally healthy reef that was recently devastated by disease.
Staghorn coral, a fast growing branching variety that look something like deer antlers, were one of the first coral species to be listed as threatened by the Endangered Species Act in 2006. Florida and Caribbean reefs have been ravaged by a number of stresses, including global threats such as rising sea temperatures and ocean acidification as well as more local and human threats, like pollution, over fishing, and development.
NOAA says staghorn coral populations have declined “up to 98 percent throughout their range” since 1980. Some of our local staghorn reefs have been wiped out nearly completely. It’s bad news for the fish who call the reefs home, but also for the state economy. Florida has 84 percent of the potential coral reef area in the United States, generating more than $6 billion a year and over 71,000 jobs.
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We are looking for solutions, including raising corals in places where babies and juveniles can be nurtured in a relatively safe place before being moved to a location where we hope to restore the coral population. Offshore nurseries are a great idea, although those can be subject to the same threats – like hurricanes or disease epidemics – as natural reefs.
A corollary technique is to grow corals under more controlled conditions in on-land nurseries where they are less subject to stress and variation. Once they grow to the right size, the next step is to transplant them. Nurturing corals in a land-based lab and then transplanting them to the ocean floor is a fairly new idea – and one among others that we hope will lead to increasing the tools in the toolbox for in restoring coral reefs.
The method sounds easy to do. Corals are famous for their asexual reproduction; a single branch can break off, fall into a crack or cement itself to the bottom, and begin to create a new colony. That’s essentially what we’re doing, although we hope we are doing it efficiently, correctly, and productively. The scientists take a small bit of branch – maybe an inch or two – and secure it to a substrate with a small amount of cement. In 400 gallon tanks, with access to good light and seawater, the corals grow very fast. In our on-land nursery, they grew about an inch per month, about twice as fast as they grow in the wild.
After a year or so of careful tending, the corals are ready to be released into the wild. You have to find the right place to put them on the ocean floor; you need to find the right reef, and you need to identify the substrate that will receive them. It needs to be cleared of algae and have a place where the cement will stick.
On February 17, the delicate corals were packed into coolers and ferried offshore. Great care was taken not to abrade or injure them in the process. Diving into a warm, calm Atlantic, the research team carefully transplanted the two-dozen branching coral colonies to a decaying natural reef line about fifteen feet deep, relatively close to shore, just off the coast of Fort Lauderdale beach.
NSU Oceanographic Center research assistants and graduate students Abby Renegar and Keri O’Neil are keeping close tabs on the transplanted coral to monitor their success rate and survivability. Is the coral still intact? Are there signs of breakage or disease? Which specimens of various genetic stocks are faring better? So far, the outlook is good and the coral appears to be doing well in their new home.
Dr. Dave Gilliam, assistant professor, is in charge of our off-shore nursery partnership with many other researchers. He is conducting similar growth and transplant activities utilizing our offshore nurseries.
There is a network of offshore nurseries that have been established up along the Florida coast from the Florida Keys to Ft. Lauderdale. On-land nurseries are still uncommon and can play a significant role. We’re expanding our grow-out facilities. With the addition of our new coral reef research center, we’ll triple the size of our nursery operation. We’re looking forward to having more room to grow coral for restoration purposes. In addition, we will have state of the art facilities for study of coral stressors in controlled fashion in order to better understand the impacts of these threats and how to better take corrective actions.
Though our transplants have worked well so far, we still have many unanswered questions. For example: What size of coral survives transplants better? When is the best time to conduct the transplantation? What genetic strains of a single species survive best? How do other species compare? How long does it take to restore a reef?
We want to figure out how to stop the stresses that are killing off coral in the wild. But, because of bigger global problems that are not easily or quickly fixed, we must also learn how to help restore our reefs and to make them more resilient.
Coral reefs are the rainforests of the sea. They create vast ecologies which result in healthy reefs and flourishing economies. Reefs are under extreme threat today and have experienced significant degradation. Finding ways to stop and minimize stresses on reefs is paramount. Research to understand how to best help restore reefs is a worthy endeavor and one in which we feel we are making a difference.