With our forthcoming documentary, 52, we address crucial issues about the oceans’ fate. Seeing as Caribbean Corals reproduce sexually every August, we decided to investigate the impact of global warming on coral reefs' reproductive cycle and their impact on ocean wildlife and humankind.
We caught up with Dr. David Vaughan, the manager of Mote Marine Laboratory’s Coral Reef Restoration Program, to learn how coral reefs are essential to the survival of the planet and how to save them.
Why are coral reefs so crucial to our oceans?
Coral reefs are important to everybody on the planet, in that they provide a good portion of the life that we know in our oceans. Our oceans are critical to the survival of us on the planet. And coral reefs, even though they’re less than 1 percent of the ocean bottom, are responsible for 25-40 percent of the world’s fisheries. So they are very similar to an oasis in the middle of a desert. And if you ask, “what good is that oasis?” It’s where all the animals go to feed and to breed and to hide and have this habitat. So it’s like the underwater jungle, and it’s very critical to most of our fishes, our shellfishes, mollusks, clams, oysters, etc.
But it also has two other very important factors in the tropical regions of the world. For one, it builds up a new bottom because corals can actually utilize calcium out of the water and make a coral reef that builds up, which protects almost all of our shorelines from things such as hurricane waves, tsunamis and tidal surges. It also is one of the most important economic values, not just for its fisheries, but for tourism. For instance, in the Florida Keys, where I am, it’s worth close to one billion dollars of the economy per year in just this county [about one billion in Monroe county alone about six billion for the state]. So in many areas around the world, it’s what every one of the tourists go to be near so that he can swim, snorkel, scuba-dive, fish, kayak, etc.
And there’s different times of reefs. There’s barrier reefs, which go parallel to the shoreline, like the famous Australian barrier reef. The barrier reef outside of the Florida Keys is what keeps all high-wave action from hitting our inhabited area. There’s also what they call patch reefs, which are small circles just like small forests, or areas that are just found close to shore and they usually are what most of the important economically valued organisms, such as crabs, lobsters, shrimp and fish, aggregate to. But we’ve lost 25-40 percent of the world’s corals in just the last 40 years. Just like with the dwindling rainforests that give us oxygen on land, the coral reefs, the phytoplankton and the seagrass, give us oxygen in the ocean. And it’s critical that we restore underwater forests, just as we learn we need to restore things like our own upland forests or rainforests.
“Coral reefs are very similar to an oasis in the middle of a desert.”
What are the causes of loss of coral?
Well, about ten years ago if you asked any coral scientist, they would all list about the same top ten items, but they would all be in different orders. And those would include things like: overfishing, loss of habitat, near shore pollution, diseases, high temperatures, coral bleaching, etc. Now almost everybody realizes that three of those top ones are all related. That is, from climate change producing high temperatures, the corals tend to bleach and turn white. When that happens they lose their ability to fight off diseases and they succumb to diseases. So they’re all related. It’s really a climate change interaction. The more invisible component of that—which most people are not familiar with, since most people are familiar with climate change—being higher temperatures or lower temperatures. If anybody wants to hold a coral in a fish tank, they know they have to keep it at a very narrow range of temperature change.
The part that most people don’t understand is ocean acidification. And that’s the part where the carbon dioxide that we burn from fossil fuels goes not only in the atmospheres which cause the greenhouse effect, but this CO2 gets absorbed into our ocean as the last sink on our planet. And when that happens, our oceans tend to turn more acidic. The CO2 ends up turning into a carbonic acid, which makes our oceans much more acidic. When that happens, it’s harder for all organisms to get calcium, which is what they use for their stone support for corals, or the exoskeleton for shrimp and lobsters, or the shell for clams, oysters and mussels. So one of the things we’re doing is looking at the effect of ocean acidification on things such as corals, and personally we want to know the effect it has on some of the corals that we are now starting to grow. To be able to plant back into the reefs and restore the reefs, we want to make sure we are using strains that are resistant to both climate change and ocean acidification.
What is the Coral Reef Restoration Program? What does it entail?
Many years ago, just ten years ago, most people never even thought that we could restore or replant our corals, thinking that they were very slow-growing and no one had ever really done it before. We’re very familiar with restoring a forest by planting trees, and more recently familiar with replanting wetlands and mangroves where they are needed. But only recently did we learn that we can actually grow corals a lot faster than we thought. We are able to grow corals by the thousands and successfully plant them back on the reefs and watch them continue to grow.
What are the main limitations to studying corals? Are you in the lab most of the time, or are you underwater?
We do both. We have what we call a “land nursery” or laboratory where we have over 10,000 corals in captivity inside water tanks, that we grow for a number of months. And then we also run a “field nursery” underwater. In about ten meters of water, we have an farm which looks like an underwater forest of plastic trees with corals hanging from them. Then, we transplant those from in the field nursery, or the ones from land, out onto a reef so that they can grow. So part of our time is on land farming, part of our time is underwater farming, and part of our time is planting out on the reef and then monitoring how well they’re doing.
August is, at least for some of the corals, their mating season. So it might be very timely for when you do the transplant.
You’re correct, corals reproduce two different ways. One is asexually by breaking into smaller pieces, and letting each small piece grow into a bigger piece, and that’s what we do mostly on land and in our field nursery. But corals also reproduce sexually, by giving off eggs and sperm in bundles, and yes, that happens synchronously in each area. It happened for us, just two weeks ago in the beginning of August. We may have another event because it’s been so warm in the beginning of September. We have collected those gametes, brought them to shore, and actually gotten many of them to survive too in the laboratory. Our intent is to try to plant corals that within one year, will grow up to the size where they will start reproducing in the wild.
Could you give us just a brief overview of the type of corals? Is mostly staghorns, elkhorns, or is there an infinity of varieties?
There’s only about 28 species of hard corals in the Florida Keys. Two of them are what we call “branching corals,” and that is the elkhorn and the staghorn. The most successful has been the staghorn in breaking small pieces, letting them grow to ten times its size in one year, and planting it back out. We’ve also been successful with the elkhorn coral in collecting the gametes and getting larger numbers of them all to survive in captivity. And then other corals are what we start on land in land tanks. And those are what we call the “reef-building corals.” Those are one of the big, mountainous type corals that you would be familiar with, such as brain coral, boulder coral, mountain coral. The things that make these big, brown boulders.