Coral reefs covers less than 1% of the ocean’s floor, but support one quarter of the world’s fisheries. Coral reefs are a dynamic environment and support a wide variety of ocean life. In this changing climate, many species of coral are suffering due to both increasing temperatures and carbon pollution. We have lost between 25 to 40% of the corals in our lifetime, and with the current climate trends, the remains of the coral populations could severely suffer in the next 100 years. Down at the Mote Tropical Research Laboratory in Summerland Key, Florida, Dr. David Vaughan and his team of researchers are making great strides in the field of coral restoration. They have developed a new technique to grow coral in the lab in an attempt to increase coral coverage on the ocean floor.
The unearthing of this new technique came about from a careless error. Vaughan had been growing corals for years, starting from a larva and working from there. It took several years for a substantial piece to grow from almost nothing. One day, Vaughan, feeling completely discouraged and losing hope for the process of coral restoration, removed one of his slowly grown coral pieces from an upper shelf in the aquarium tank and put it on the bottom of the tank.
During the move from the upper shelf of glory to the bottom dregs of the tank, a couple coral polyps broke from the calcium carbonate skeleton. Vaughan thought there was little chance that this damaged coral would have a chance to make it. Two weeks later, Vaughan came back to examine the tank. The sad, little piece of broken coral had grown back to its original healthy condition. In fact, the couple polyps that broke from the larger piece of coral had started to generate more polyps on their own. The multi-year process of growing coral from a larva now flashed before Vaughan’s eyes in a matter of weeks. Vaughan simulated the mistake, breaking the coral again, to determine the smallest piece of broken coral that could be used. He concluded that it only took a single polyp to regenerate more coral. And just like that, completely unintentionally, a new technique was born.
THE PROCESS OF MICROFRAGMENTING
Dr. Vaughan describes himself as a “gardener in a greenhouse producing hundreds of trees by way of tissue culture.” The technique Dr. Vaughan developed is known as microfragmenting, in which new coral polyps grow from broken pieces of coral. The new method allows coral to grow over 25 times faster than natural growth.
What Vaughan discovered is that there is something about the broken pieces of coral that stimulates the corals to heal at rapid speed and grow healthy. Once the polyps grow into substantial pieces of coral, divers transplant the coral onto the existing reef. The growth process, starting from a single polyp, takes only a couple of months.
Sometimes coral pieces that are adjacent to one another will fuse together into one larger mass. Vaughan believes that this technique has great potential: “If somebody said now, for ten million dollars, could you take the elk horn corals off the endangered species list, I’d say yes. It can be done. And it can be done in the next few years.”
The biggest threats to corals are the rising ocean temperatures and the increased levels of carbon dioxide in the environment that are sending ocean acidification levels to new heights. Elevated temperatures can cause coral bleaching, where corals expel their symbiotic algae that live in their tissues. This process turns the coral white in color. Although the coral is not dead, they are under high stress and become more vulnerable to mortality.
Corals are also particularly sensitive to the increasing acidity in the ocean. Corals build their skeletons by bonding calcium ions with carbonate present in the surrounding water. When carbon dioxide dissolves in seawater, carbon and hydrogen ions are released. Hydrogen ions also have an attraction and tend to bond with carbonate, forming bicarbonate. Here is where the issue arises. The hydrogen ions released from dissolving carbon dioxide compete for carbonate with skeleton-building organisms. This makes access to carbonate more difficult for corals. Hydrogen ions can also break down existing calcium carbonate bonds in the search of carbonate (if not enough is present in the water), dissolving the skeletons of coral. Fortunately, some species of coral are able to use bicarbonate instead of carbonate to build their skeletons. This gives these species of coral an advantage in an acidifying ocean.
At the Mote lab, Vaughan and his researchers have access to an apparatus that simulates future ocean temperatures and pH levels, at both 50 and 100 years. This machine allows the team to learn how different species of coral will react to the changing ocean conditions. They have learned that certain strains of species are more tolerant than others. The ultimate goal is to determine which species of coral are most resistant to future changes in ocean temperature and pH, so that the team can produce the most resilient corals. Currently, the Mote lab is growing corals faster than they are allowed to transplant them onto the reef. Vaughan’s sentiments say it all: “There is no reason, as a worldwide, we can’t replace these corals and get our oceans back to the way they used to be.”
**All photos EXCEPT the coral bleaching photo are from: http://www.theatlantic.com/video/index/423696/a-coral-reef-revival/