Mason Team Dives Deep into the Mysteries of Coral Disease

Posted: October 30, 2006 at 1:00 am, Last Updated: November 30, -0001 at 12:00 am

Mixing marine expoxy
PhD student Geoff Cook mixes marine epoxy underwater to patch a hole where he extracted a sample of a diseased coral.
Photo courtesy Diana Schmitt

By Tara Laskowski

George Mason University is not located on the coast of Bermuda or the Florida Keys. The scuba diving classes held on campus happen in the depths of the swimming pool in the Aquatic and Fitness Center, not the Atlantic Ocean or the Gulf of Mexico.

Still, the fact that the university is nowhere near the tropics doesn’t stop Bob Jonas or his students from doing the work they are most passionate about: saving the coral reefs.

Jonas, chair of the Environmental Science and Policy Department, visits the tropics of the Bahamas, the U.S. Virgin Islands and the Flower Garden Banks National Marine Sanctuary in the Gulf of Mexico several times a year with a team of students to study and do research on coral reefs.

“Coral is a fascinating animal,” says Jonas — and yes, coral is an animal, not a plant. Corals are tiny animals, called polyps, and each coral secretes limestone around itself, forming a skeleton. The polyps divide as they grow, forming coral colonies.

As the colonies build up on top of each other, they gradually form a coral reef. The reef at Andros Island is the third largest in the world, stretching 170 miles. Thousands of different animals and plants live in the reef and live off the reef, making for a diverse environment second only to the rainforest.

Mapping the Disease of the Reefs

But if diving into tropical waters in sunny places sounds like a dream job, think again.

“The coral reefs are dying,” says Jonas. “Being eaten alive, and we don’t know why.”

Bob Jonas and Geoff Cook processing coral disks
Professor Bob Jonas, left, and Geoff Cook process coral disks aboard ship after collecting samples.
Photo courtesy Emma Hickerson

Being animals, corals, like people, have specific diseases associated with them. There are approximately 20 known coral diseases that have been identified since the 1970s, but the one that Jonas is most concerned about is the “white plague.” This disease eats away at the top tissue of the coral, leaving only a limestone skeleton behind.

“It’s like a fast leprosy,” says Jonas. “It’s absolutely devastating because the corals never grow back.”

The team has conducted studies that show the disease can easily destroy up to one centimeter of coral tissue a day and kill entire small colonies in a matter of days. Since corals grow slowly, perhaps one centimeter a year, this one disease is clearly a major threat. Jonas estimates that 10 to 20 percent of coral in the world is now dead, and the problem is not getting any better.

“I don’t even like to dive on some reef sites anymore. It makes me cry to see the reefs in the state they’re in.”

Even with all this dire news, Jonas says he has a passionate Mason team researching and mapping the disease. Along with faculty members Esther Peters, one of the world’s premiere coral histopathologists, and Patrick Gillevet, who uses state-of-the-art techniques to study molecular evolution and gene sequencing, Jonas is working to identify the agent or agents causing the disease and the overreaching environmental changes that may have developed the disease in the first place.

“About 99 percent of our time is in the lab,” says Jonas.

Their work so far has identified a specific community of microorganisms that seem to characterize the diseased colonies. However, they are still trying to determine if this community is unique to the disease and if it differs in different parts of the world.

A Tropical Education

Geoff Cook, a PhD student in the Department of Environmental Science and Policy, has spent the past three years scuba diving on coral reefs in the Bahamas, Florida Keys National Marine Sanctuary, Dry Tortugas National Park, Flower Garden Banks National Marine Sanctuary, Cayman Islands and Bermuda.

Geoff Cook
PhD student Geoff Cook
Photo by Evan Cantwell

As part of his dissertation, Cook has been studying the coral disease known as “white plague type II” or WPII. It is known to affect at least 18 different species of reef-building corals from the greater Caribbean region. This disease has proven to be capable of causing swift and efficient mortality of corals and poses a major threat to the health of remaining reef systems.

For his research, Cook has been characterizing the bacterial communities associated with WPII-diseased as well as apparently healthy colonies of the boulder star coral Montrastraea annularis in hopes of determining the cause of this damaging disease.

To acquire his samples, Cook uses a coring tool to collect multiple sections of coral tissue and skeleton from both diseased and apparently healthy colonies. All samples are processed in the field, then shipped to Mason’s laboratories for further analysis using both culture-dependent and molecular techniques.

When he graduates from Mason, Cook would like to pursue a career that blends active research with the specific aim of putting the products of scientific inquiry to use to conserve coral reef ecosystems. He would also like to offer assistance and education to developing tropical island nations to create and implement environmental policies that foster sustainable use of these natural resources.

“There seems to be a growing need for the scientific community to be able to work in collaboration with a society’s governing officials to make sure policy makers are properly and accurately informed,” Cook says.

The team, which also includes graduate students Paige Rothenberger and Masoumeh Sikaroodi, believes the disease developed because of large-scale environmental factors, the most important being increased water temperature worldwide. Other factors that might contribute include sewage contamination, erosion and sedimentation and increased ultraviolet penetration.

Even if the cause of the disease is pinpointed, Jonas is unsure how the problem will be solved. He is hopeful that dedicated scientists will continue to work to save the reefs, not only for the preservation of this strange and beautiful animal, but also for the safety and livelihood of humans.

“Coral is the barrier for the ravages of the sea,” he says. “It is a natural protection for us.”

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