FROM HERE TO THERE AND BACK AGAIN

Marine biologists don’t always end up living near the ocean. Michael Childress spent part of his career at Idaho State University, about a four-day drive from the Florida Keys.
But before his stint at Idaho State, Childress began doing underwater research in the Keys in 1991 when he was a graduate student at Florida State University. That’s when his passion for this wondrous string of tropical islands first consumed him. Childress knew that he didn’t want to stay in Idaho forever, so when a faculty position became available at Clemson, he was quick to take it. Tigertown isn’t exactly a stone’s throw from the Conch Republic, but it’s a whole lot closer than a state famous for its potatoes.
An evolutionary behavioral ecologist whose research focuses on understanding how marine animals respond to habitat loss, Childress joined Clemson in 2001 and is now an asscoiate professor in biological sciences. Two of his main courses — Marine Ecology and Behavioral Ecology — are thriving despite the University’s relative lack of resources dedicated to marine science. In addition, he teaches a Creative Inquiry undergraduate research course on the Conservation of Marine Resources.

“This invaluable natural resource has been in precipitous decline for the past 30 years. Marine biologists consider these reefs to be the most critically imperiled ecosystem on the planet.”

Over the past 15-plus years, Childress and his students have managed to make dozens of trips to the Keys to study spiny lobsters, blue crabs and anemone shrimp. They’ve helped finance these trips by doing everything from using National Oceanic and Atmospheric Administration Sea Grant awards to holding bake sales.
Smith began working with Childress in 2010. After earning her bachelor’s in ecology and evolutionary biology at the University of Colorado Boulder, she came to Clemson first as a research assistant and then as a master’s student. When Childress and Smith began to discuss her research options, Smith mentioned that she was interested in studying corals.
“I didn’t work on corals,” Childress recalls. “So, when Kylie said that she wanted to do a project about corals, I told her that, at least at first, it would have to be related to some aspect of animal behavior. Because that’s what my lab at Clemson does. Eventually, we decided that Kylie would begin by studying the effects of parrotfish populations on the health of coral reefs.”
Parrotfish are herbivores, and one of their favorite foods is macroalgae that compete with coral for nutrients and space. Smith’s initial research tested the hypothesis that coral decline was due to harmful macroalgae growing out of control due to a loss of reef herbivores. But she found no strong evidence that coral was being inhibited by macroalgae overgrowth or being rescued by parrotfish eating it. This became the subject of her master’s thesis, which she defended in 2015.

Childress’s Creative Inquiry class has functioned as a research team for Smith in her master’s and doctoral work. The composition of the class changes a bit from semester to semester, but these students have traveled back and forth to the Keys, become dive-certified and participated in almost every facet of Smith’s research. Childress has mentored Smith, and Smith in turn has mentored these undergraduate students who have caught her passion for the world underwater.
Smith’s early research taught her many things about coral reefs. For instance, different species of corals seemed to have different sensitivities to warm-water conditions, which can cause coral to turn completely white. This is called coral bleaching, which results when corals expel algae that reside in their tissues. Corals can survive bleaching events, but the accompanying stress often results in widespread damage.
“Looking at the interactions that have been taking place between these organisms had been the foundation of my research,” Smith says. “But we’ve had other offshoots. We’ve looked at the effects of overharvesting of fish. We’ve looked at how differing water quality can influence some of these relationships. And we’ve monitored how changes in temperature can influence coral growth.”
In 2013, Smith conducted her first coral restoration study. She and her team transplanted 84 coral fragments on seven reefs throughout the Middle Keys. What happened next proved to be a hard lesson in coral sensitivity. She witnessed firsthand that prolonged periods of higher-than-normal water temperature can cause coral bleaching and mortality in both transplanted and native corals.

“Childress has mentored Smith, and Smith in turn has mentored these undergraduate students who have caught her passion for the world underwater.”

“In 2014 and 2015, we had intense warming during the fall months, and that triggered major bleaching events across the Caribbean, including here in the Keys,” Smith says. “Some of the corals we had transplanted showed signs of bleaching, while others didn’t. But by following our corals, we saw that they seemed to recover more quickly and be more resilient in 2015 than they had been in 2014. And so, we think that there might be some local acclimatization going on. This could mean that corals that have previously experienced high temperatures are better able to resist bleaching the next time they occur.”
What Smith learned between 2013 and 2015 prompted her to broaden her focus to include a wider range of interactions in the coral reef community. In 2016, she began to devise a structured-equation model that could be used to predict the best conditions for coral transplant success. Her hope was that environmentalists who might eventually follow this model would be able to increase survival rates. To test her model, Smith picked out eight near-shore and offshore reefs in the Middle Keys that differed in structure and composition.
In early 2017, the final phase of her doctoral research began.

CREATING A MODEL FOR SUCCESS

Smith chose to transplant 192 fragments of four different varieties of corals at the eight reefs. Each variety would have 48 fragments. The corals varied in vulnerability. Acropora cervicornis (Acer), a branching coral also called staghorn, was the most vulnerable and is an endangered species. Siderastrea radians (Srad), a stony coral known as starlet, was the hardiest. Orbicella favolata (Ofav), a stony coral called mountainous star, and Porites astreoides (Past), a stony coral known as mustard hill, fit somewhere in between.
Step one was to secure the coral fragments and transfer them to holding tanks. Step two was to transplant the fragments. Step three was to document the growth and survival rates every several months from October 2017 through June 2019. Step four was to compare reef and transplant data with her predictive model to see if it worked.
In March 2017, Smith, Childress and four other members of the Creative Inquiry team — Kara Noonan, a new graduate student; Randi Sims, a recent Clemson graduate with her bachelor’s in conservation biology; and undergraduates Sydney Whitaker and Sara Rolfe — traveled to the Florida Keys National Marine Sanctuary coral nursery in Key West to harvest fragments of Srad, Ofav and Past.
“When we got into the water, the visibility was barely the length of our arms,” Childress says. “The crates were suspended beneath docks in the marina, and we had to pick out the correct fragments in near darkness. This turned out to be one of the most challenging dives of the entire project. But in the end, we were able to get at least 48 fragments of each of the three species. We later obtained our staghorn fragments from an offshore nursery.”

Some of the fragments were too large and had to be cut to the appropriate size (approximating a silver dollar) using a table saw. Corals are extremely sensitive to changes in water temperature, but are quite hardy when it comes to being cut to pieces. The fragments were transferred from Key West to holding tanks at the Keys Marine Laboratory in Long Key.
Smith and her team then constructed a couple of hundred PVC frames that would be used to mark the locations of each transplant. For identification purposes, each coral would also have an individually numbered tag. Fifty-meter-long transect tapes would serve as orientation on the reefs.
“Just building the PVC frames was a major effort,” says Smith, a certified dive instructor who has trained most of the students who dive with her. “We had to secure them on the reefs with rebar. We have a lot of footage of us hammering rebar underwater, which is not the easiest thing, because you’re constantly fighting going up and going down. But making the frames in advance really paid off. It would have been maddening to have had to build them at the same time we were transplanting the corals.”

A RAUCOUS RIDE TO A PEACEFUL PLACE

Cruising wide-open in an 18-foot skiff on the ruffled waters of the Florida Keys is not for the faint of heart. Leaps and bounds bruise your senses — and also your knees and lower back.
But once you arrive and drop anchor over a coral reef in the Florida Keys, you realize it’s most definitely worth it. The bluebird sky and the surface of the sea are both magically beautiful, but what lies 15 feet or so beneath the surface dwarfs all else. This is why Smith does what she does.
It is now June 2017. Smith and her team, already adorned in wetsuits, don scuba gear and prepare to plunge into the warm water. Their assignment today is to transplant coral. Three of the varieties will be put in place using a cement mixture. The fourth — the fragile staghorn — will be attached using concrete nails and tie-wraps.
Noonan has been assigned the unenviable task of mixing cement with silica powder in plastic bowls and then placing fist-sized globs of it into plastic ziplock bags. By the end of the day, she is so covered with powder, she looks more like a Greek statue than a scuba diver.
“There’s a reason they use trucks to make cement,” she says sardonically.
With Noonan remaining onboard, the other four members of the team go about the arduous process of transplanting dozens of fragments of coral. Whitaker and Rolfe take turns bringing the cement and coral fragments down to the first PVC marker. Smith then smooshes the cement onto the relatively flat surface of dead coral skeleton and presses the living coral fragment into the cement. Amazingly, the cement starts to harden even though it is underwater,  and the fragment holds. One down, 191 to go.
“There’s nothing like being underwater,” Whitaker says. “You think it’s silent at first, but once you get used to it, you can hear all the snapping and all the crunching of the different fish. It’s just amazing to be able to see everything moving around you and how much life there is in the ocean.”
“I didn’t expect the work to be as exhausting as it is,” Rolfe adds. “But it’s wonderful work, and the things we see on a daily basis continue to amaze me.”
Meanwhile, Sims records what species of coral is transplanted where, making sure that everything is well-organized and properly documented. “I’ve done a lot of data collection and analysis with this project, both in the field and in the lab at Clemson,” Sims says. “And it’s been really cool to see the way the project has grown.”
At the end of the day, the team is exhausted. And this is just one day out of many before all the fragments are in place. But they wouldn’t have it any other way.
“I’ve grown a lot through the process and have even become a mentor,” Smith says. “I didn’t expect to love my ‘kids’ as much as I do. Each student has taught me a lesson and left me with a wonderful memory. It’s emotionally taxing to go out and see a new disease has popped up or one of the corals you transplanted just a week ago has already been taken out by something. But it’s worth it to know that I’ve had so many wonderful undergraduates who have been inspired by this work and now want to go out and help change the world.”
One day, Childress takes the team out to a reef that none of them have seen before — not for research but just for recreation. Unlike so many other coral reefs in the Florida Keys, this one is in pristine condition, and the water enveloping it is as clear as air. A forest of purple, yellow and teal sea plumes sways gently in the current. Magnificent boulders of star coral sprout from the sandy bottom. Parrotfish, damselfish and angelfish dart this way and that, though a few nestle motionless in the dense cover, as if asleep. What at first appears to be a long stick buried in the sand turns out to be the tail of a stingray, the rest of its body hidden from view. If you look closely enough, however, you can make out a pair of watchful eyes.
“We occasionally explore new locations to identify future reefs for coral restoration or other experiments,” Childress says. “This reef had one of the highest density of corals of any reef in the middle Florida Keys. It was exciting for me to see this reef but even more exciting to watch my students’ reactions. It was as if we had gone back in time, and they were seeing a reef the way they used to be.”

WEATHERING THE STORM

Even the most precise and best-laid plans can be derailed by unexpected circumstances. When Hurricane Irma slammed southern Florida on September 10, 2017, the monstrous storm devastated large swaths of the Florida Keys.
The Keys Marine Laboratory, a state-owned marine field station where Smith and her team are permitted to base much of their operations, experienced severe flooding. But at least the team’s boat, the R/V Argus, survived the storm intact.
In October 2017, the team visited six of its research reefs, and Smith discovered that more than 50 percent of her transplanted corals had been either killed, crushed, dislodged or buried in sand by the storm. As feared, the fragile staghorn corals had suffered the most damage — almost 80 percent lost — yet more than 50 percent of the hardier stony corals had survived.
Smith’s original experiment was to see if she could predict the coral fragments’ long-term resilience to climate change, but now her study will include how quickly and in what ways the reefs can rebound from hurricane disturbance. She will examine how this sudden change in community structure influences the settlement and growth of new corals, including her surviving transplants. To this point, her team’s overall conclusion is that despite the severe effects of thermal bleaching and hurricane disturbance, the reef communities of the Florida Keys are hanging in there by the tenacity of a few species of corals that show high resilience. However, continued monitoring of changes in reef community structure will be needed to understand the long-term resilience of the Florida Reef Track.
The good news is that reefs are well-adapted to recover from natural disasters. The bad news is that climate change doesn’t come and go as fast as a hurricane.
The starkness of this reality has caused some researchers to give up. But not Smith. When the silt from Hurricane Irma finally settles, she’ll be back at work, displaying the kind of resilience she hopes to find in her coral transplants.