Hurricane Irma could end up costing Florida’s economy $70 billion, and not all the damage wreaked when it struck in September happened above the water.
The only coral reefs in the contiguous United States also took a hit. The storm’s wave energy picked up sediment that sandblasted corals, broke off large sections known as “heads” and embedded rubble deep into the reef structure.
A team lead by the Florida Keys National Marine Sanctuary and the National Oceanic and Atmospheric Administration (NOAA) is now trying to find out exactly how much damage was done.
After Irma, divers quickly sprang into action because time was of the essence. Even if corals were not initially killed by the sand, rubble and waves, they may tip over or become covered in sediment, which prevents their polyps from feeding and blocks sunlight needed by their symbiotic algae.
The team’s rapid assessment focused on 57 key sites, after which they decided which needed the most attention. Next, divers including Lauri MacLaughlin went to work to save as many corals as they could.
MacLaughlin, a regional research associate at the NOAA’s Office of National Marine Sanctuaries, began her career at Looe Key, about 25 miles (40km) east of Key West, Florida, and has worked extensively on many of the reefs that she is now trying to save. The recovery work may be as simple as propping a coral head back up and gluing it to the seabed. Sometimes, however, the extent of the damage and weight of the heads makes this no easy task. While MacLaughlin says this first triage step has gone well, the larger cleanup of the reef will take a long time.
Oceans Deeply spoke with MacLaughlin about her experience diving and cleaning up the reefs, how Irma damaged the corals and why she is optimistic that Florida’s reefs will recover.
Oceans Deeply: Can you describe the difference between what you saw before Hurricane Irma and what you saw recently?
Lauri MacLaughlin: It varied from reef to reef. It seemed like some of the shallower reefs had a broader range of impacts. It was rather alarming and slightly devastating [to see], but for all of the corals that we saw disturbed and turned over and flipped, we also saw amazing corals that were incredibly resilient and still fanning and holding their own. I remember feeling very, just, relaxed and thankful that there were some corals that could hold up against that kind of wave energy.
Lobster traps were a very large part of [the debris] we observed out there. We have our hands full, as one our next phases of triage is to arrange with some members of the public and a local charter operator to remove that debris.
Oceans Deeply: What is the impact of those traps on the corals?
MacLaughlin: I believe that during our Sanctuary Advisory Council Meeting in October, we had the fishers there, and there were 130,000 traps unaccounted for. The kinds of impacts we’re seeing are abrasion and entanglement on corals and on the reef structure itself. I’ve found fragments of wood slats and cement bases that [fishers] use to weigh these traps down; and even wire mesh so embedded within the rubble that you couldn’t pull it out without having a tool or help from some other divers.
We also saw not just trap debris, but boat parts. We saw pieces of fiberglass, and I think that I even saw a section of a hull. On one of our reefs we found what looked like a concrete pipe that was maybe 15-20ft (4.5-6m) long, which had rolled around and scarified an entire area that [now] looked like a parking lot.
This is an issue that we want to stress with the community down here: that when you put out these large objects to attract marine life, like an FAD [Fish Aggregating Device] these objects are not permanently attached to the bottom. They create a serious impact and injury threat during large hurricanes and winter storms.
Oceans Deeply: How do you go about saving and reattaching corals?
MacLaughlin: We used some epoxies. We tried to use cement, but cementing was not an option because of the weather conditions and the surge. We worked [to get] maybe two or three or four edges of the coral epoxied down; the idea is that will give the corals a fighting chance in the next couple of months to reattach naturally and repair themselves.
We tackled probably thousands of small corals – I’m talking about corals that are softball-sized or smaller – and several hundred medium-sized. We estimated that we repaired about 100 larger corals, which I describe as around the size of a small table to dishwasher-size. The Force Blue Team, the salvage team that we worked with, had lift bags that we used to raise close to 15, if not more, large corals.
Oceans Deeply: How long will it take these corals to recover?
MacLaughlin: It is highly variable. An elkhorn coral can grow about 5-6in (13-15cm) a year in ideal conditions; a mountain star coral may only grow 0.4in (1cm) in a year. It is interesting to see how rapidly [fragmented corals] grow down and sideways to reattach. That can happen rather rapidly, compared to their normal growth rate.
This is one of the best times of year to do triage because you’re not up against hurricanes; hopefully, you’re not up against diseases and coral bleaching because those are not common in this season.
One of the other impacts of hurricanes is that they move sediments around. There are a couple of ramifications of that. One is, sediment being raised up off the bottom and powered into the reef by wave energy can cause both a damaging and a cleansing effect. The damaging part is that it basically sandblasts the reef, but it tends to break off some of the algae and overgrowth on the reef that is competing with coral for space.
Oceans Deeply: Having worked for so long in this area, what was it like seeing the reef like this?
MacLaughlin: I spent a lot of my time working at the Looe Key sanctuary, where I started in 1987 and worked until about the late 1990s, early 2000s. Looe Key was my home base for many, many years.
Visibility has not been great out there. You couldn’t see the seascapes or the extent of the injuries. This somewhat impeded our ability to work, but at the same time I was glad I wasn’t able to see it, because I know that I would have been really saddened.
However, these systems have been through this before. For every five or 10 corals that we saw flipped over there were at least another five or 10 that were still upright and amazing that you just want to hug and say: “Thank you for surviving the hurricane!”