Wednesday, May 21
We set out much earlier and made a stop at the Tavernier Nursery. Corals had been staged the day before while I was fragging and cleaning. This means they were either placed loose into the milk crate containers I constructed yesterday or were strung on staging trees in bundles of ten on monofilament line. The milk crates can sit on the substrate but the bundles were hung on special coral trees and ready to go. In the interest of saving time, only Coral Restoration Foundation (CRF) employees jumped in to retrieve corals for outplanting. I stayed on board with the Georgia Aquarium staff and crew. It didn’t take long. In 20 minutes or so we had all of our corals on board and ready to go.
Our first two dives at Snapper Ledge focused on planting the Staghorn corals. Breaking up into groups of 4, we were each given areas to plant clusters (close groupings of 10) on the reef. For each site, we were given 10 fragments, a fistful of mixed epoxy and a hammer.
The two part epoxy is mixed immediately upon entering the water so that it will be the proper consistency when securing corals. There seems to be a “goldilocks period” about 20 minutes after mixing where it works best. Earlier than that and it is a bit soft and later it begins to harden.
The large, branched Acropora cervicornis fragments are laid out on circular area no larger than a hula hoop…usually closer. By keeping them close together, it increases the chance of adjacent colonies fusing together to make a larger colony. Three contact points with the substrate is desired because it minimizes the chance of a coral being “rocked” free by the surge. After contact points are determined, a heavy hammer is used to chip away the biofilm at the crust of the rock at these locations. Any offending organisms in the immediate area (fire coral or gorgonians usually) are removed. The encrusting biofilm around the contact points is cleaned down to bare white to allow for maximum bonding strength. Then, a grape sized daub of epoxy is applied to these areas and the coral is pressed into it. Oftentimes, after setting the coral aside to apply epoxy, I completely forgot what orientation I had the coral in and had to start over. Very frustrating!
Excess epoxy is pulled up over the coral tissue around the points of contact. Then, the strength of the bond is checked (scientifically) by waving your hands furiously around the new outplant. If it stays put, you can move on, but if it wiggles even just a little bit you have to start over. That also helps to clear any debris out of the area. CRF staff applies tags to the substrate with epoxy once each cluster is finished.
Between the four divers in my group, we planted around a dozen clusters before doing a quick maintenance run on established colonies. Basically, diseased or damaged areas of the corals are removed and any broken pieces are reattached. Offending organisms, including predators and encroachers are removed from the site. Growth of planted colonies in the area is impressive and many have fused together to make a larger colony. We headed back to the boat.
After boarding, the most exciting development was the announcement that we would be planting some Elkhorn fragments (Acropora palmata)along with the Staghorn (Acropora cervicornis) we’d been working on all morning! CRF staff had picked up some fragments from the nursery at Snapper Ledge while we were planting Staghorn corals.
Acropora palmata has only been farmed in the nurseries since 2009, and it is much more difficult to farm and outplant efficiently. In 2012, CRF performed the first ever outplanting of farmed Elkhorn Corals in the United States. Staghorn branches like a tree, making it easy to find three small points for attachment to the substrate. In contrast, the smaller Elkhorn fragments are generally squarish blobs of dense coral growth. This requires epoxy to be applied around all of the edges of the piece. It requires a lot more epoxy to attach a much smaller fragment of Staghorn. Also, since there is no real balance point, it is difficult to position it naturally. In terms of farming, the Staghorn is not as easily maintained in a tree setup and are sometimes still grown on blocks and disks.
We moved on to Pickles Reef to plant the Elkhorn. This final dive of the day involved fewer corals but was much more difficult. Surge was extremely heavy in this area and at times you were forced to hang on to the bottom just to stay in place. Forests of gorgonians swayed back and forth violently with the surge. Fragments of Elkhorn coral were much harder to secure than the Stagohorn. Acropora palmata is planted in clusters of 3, spaced no further out than the diameter of a basketball. I have to admit that the end result of these plantings is not as aesthetically gratifying as the Staghorn, but perhaps more important to the ecosystem. I’m very proud to have played a part in this important process.
Acropora palmata in the Caribbean and Western Atlantic serves the same function as barrier islands in the Mid Atlantic states. It serves as a buffer against storm surge on the mainland. Historically, massive stands of Elkhorn covered shallow water flats. This causes large swells to break and dissipate energy that otherwise would be borne by the coastline. It is estimated that the reef crest dissipates around 90% of wave energy that is otherwise destined for the shoreline. When combined with intact mangrove banks on the islands themselves, erosion is held in check. Development of the shorelines and damage to the reef compromises this natural protection, however, and more damage is incurred during storms.
By dissipating this energy and creating a barrier, the Elkhorn corals can also create refuge for many organisms that are not tolerant of such strong surge. Indeed, it is clear that even fish diversity is higher close to restoration sites.
It was quite challenging, but we finally got all of the fragments planted and headed back to the boat. I am exhausted from fighting the surge on that last dive, not to mention spending almost 4 hours in the water today.
After cleaning up, I met with the Georgia Aquarium crew, Ken and his wife at a deli/pizza place just down the road. Ken is quite charismatic and very good about making sure he spends an adequate amount of time with each of his volunteers, which is important. It makes you feel valued and he’s very genuine. That’s a very attractive and useful quality, especially for someone who gets his funding through grants and donations!
Time for some sleep…four more dives planned for tomorrow.
Read dive logs from each day of the trip!
Dive Log – Saving Coral Reefs: