The Explorers - Under the sea
Forty-two lionfish. That’s how many Danielle Dixson and colleagues speared during a single day of diving at the Carrie Bow Cay research station in Belize.
This invasive species has infested the waters of the Caribbean. For scuba-diving scientists like Dixson, studying coral reefs here isn’t just difficult, it’s dangerous.
While spearfishing, lionfish spines poked through the “lionfish-proof” catch bag trailing behind Dixson. A quick turn, a bump of the catch bag, and three spines containing painful venom lodged deep in her leg. The assistant professor in Georgia Tech’s School of Biology then began monitoring the swelling in her leg — while still monitoring coral spawning for her research. Dixson worked through the pain to finish her coral larvae collection but got off the island before things took a turn for the worse.
“The ER doctor told me if I had stayed on the island for one more day, I might have had permanent soft tissue damage,” Dixson said.
Part of a lionfish spine is still buried in her leg. She keeps the remainder of the spine in a glass jar on her desk.
Photos: Danielle Dixson - Carrie Bow Cay
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Belize isn’t the only remote location where Dixson has conducted research missions. She has traveled to the Great Barrier Reef and to Fiji, where she collaborated with Mark Hay, a professor in the School of Biology, who once spent 10 days underwater in the Aquarius lab off the coast of Florida to study coral reefs.
In 2014, Dixson and Hay published an article in the journal Science showing that restricting fishing in certain areas might not be enough to help damaged coral reefs rebound beyond those borders. The researchers traveled to the main island of Fiji, on the country’s coral coast. They discovered that coral larvae and juvenile fishes are picky about where they choose to settle. Both coral larvae and juvenile fishes can smell the difference between a reef that is unhealthy and one that is a suitable home.
For the study, the researchers dove among some of the most breathtaking coral reefs on the planet, collecting samples of fishes and coral. They lived in a village called Votua, near the town of Korolevu on the island of Viti Levu, where overfishing of a key species has led to coral reef degradation. To reverse this trend, they not only studied the reefs, but also navigated cultural differences to inform the village elders that they needed to protect certain key species so their reefs would stay healthy enough to feed future generations.
“We sat on the floor, drank kava, and ate fish heads with the chief,” Hay said. “Culturally, that’s what the leaders do, and this is where the important discussions and information-sharing take place. At the end of the evening, if they trust you, they’ll tell the villagers, ‘OK, no more taking this fish.’ In some villages, that works pretty well, sometimes it’s a little chancy.”
Kim Cobb, an associate professor in the Georgia Tech School of Earth and Atmospheric Sciences, also scuba dives in the name of science, but she does it with a big drill. Cobb and her lab explore the corals of Christmas Island, an atoll in the middle of the Pacific Ocean. They use a massive underwater hydraulic drill with a diamond-encrusted drill bit to bore into coral, removing core samples that provide clues about how the climate has changed over the past 10,000 years.
“I do all the drilling myself,” Cobb said. “It’s tough. The drill is very heavy underwater, and there are always surging currents.”
Cobb’s lab focuses on so-called hindcasting, comparing models of Earth’s past climate with data from fossil coral records, which is critical to optimizing climate models that will forecast, among other things, how the El Niño climate pattern will change as the Earth’s climate changes. Samples from modern coral reefs provide data from the past 50 to 100 years. Older coral can provide data from the past centuries and millennia.
One of Cobb’s drilling expeditions was featured on Showtime’s Years of Living Dangerously. The show followed her to the equator in 2013 to capture the drilling process in action. For her next mission, Cobb and her students will return to Borneo where they will study cave stalagmites that also hold clues to the Earth’s past climate.
“These are stunning sites, it’s just incredible that we can go there and do research,” Cobb said.