New research conducted in the Great Barrier Reef has pinpointed the specific genes that have the potential to make the corals there resistant to environmental change. Marine biologists in the Arab world hope to do the same for corals in the Gulf.
Emily Howells, one of the scientists involved with the research in Australia, now works at New York University in Abu Dhabi. She has teamed up with David Abrego at Zayed University. They are working with a coral species in the Arabian Gulf to find the genes responsible for creating resistance to increasing temperatures. Such a discovery would improve efforts to conserve the region’s reefs, the scientists say. If researchers could test coral populations for resistance to rising water temperatures, then environmental officials could focus conservation efforts on corals they have a better chance of saving.
“For example, if you want to have a marine reserve then we can use genetics to design its boundaries,” says Howells. “That way we can make sure it has the most number of resistant corals.”
Such efforts could also help to regenerate reef systems that are in decline. “If we’re going to transplant, we don’t want to take any old coral,” she says. “Ideally we’d want to preferentially select resistant individuals.”
Coral reefs are often said to be the rain forests of the seas; they’re home to an incredibly diverse set of creatures and plants—perhaps as many as nine million different species—that build their habitat around the corals. The reefs play host to all of this biodiversity despite occupying just 0.2 percent of the ocean’s floor.
Many scientists are researching the potential of chemicals produced by species living in coral reefs to be used in medicines. Coral reefs are also important economically, attracting tourists and supporting fishermen. Some estimates place the global economic contribution of coral reefs in the tens of billions of dollars each year.
But coral populations across the world are in rapid decline. Between the 1950s and the end of the 20th century, the planet lost almost 30 percent of its reefs. The main menace is a consistent rise in sea temperature. But variations in salinity, real estate development, particularly in the Arab region, and ocean acidification caused by pollution, also contribute to killing coral.
Corals in the Gulf and the Red Sea don’t have it easy. The temperatures in these waters are perhaps the highest that corals can tolerate. A coral cluster from the Caribbean would be unlikely to survive if it was transplanted to the Middle East.
This makes coral reefs in the region all the more important to study. “This region is almost like a crystal ball for what may occur elsewhere,” says Abrego.
“There’s probably a genetic basis for why these corals are in the Gulf,” he adds. “We need to take it a step further and do what Emily and her colleagues did in Australia.”
Howells’ colleagues analyzed samples of corals collected from the Great Barrier Reef under both normal and environmentally stressful conditions. The research team also conducted experiments in the laboratory, where they increased water temperatures to stress the coral.
They compared the genetic makeup of the corals that suffered least in all three scenarios. They looked for consistent overlaps to identify if they all shared a specific version of individual genes. If they did, the scientists theorized those genes were responsible for their genetic resistance to higher temperatures.
In a paper published last week in the journal Science Advances, Howells identified two such genes. These genes were associated with antioxidant production. “Stress causes cells to produce what’s known as reactive oxygen species, which can be damaging to tissues and DNA,” explains Howells. “For that to be neutralized, you need antioxidants.”
That Howell was able to see the same type of gene expressed among the stress-resistant corals in all three scenarios gives Abrego confidence that the correct genes were identified.
“It’s one thing to observe it in the field; it’s another thing to show it in the lab,” he explains. “It’s extremely important when you’re talking about genetics.”
Abrego’s previous research has shown that damaged coral reefs can enter a vicious cycle. He showed that marine wildlife actively shuns reefs of declining health, making it even harder for them to ever recover. (See related article: Why The Gulf’s Ailing Coral Reefs May Never Come Back.)
That’s why Abrego and Howells want to replicate the research done in Australia with coral species native to the Gulf and Red Sea. Genetic knowledge of the region’s corals could prevent reefs from entering this spiral of decline or make it easier for them to pull out of it.
“The Australian study provides us with a roadmap to do this,” he says, “and it could help the fight back.”
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