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Reefs at risk: Roundup at the not-so-OK coral corral

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bleached coralCoral, the reef-building organisms responsible for some of the oceans’ most vital ecosystems, are in trouble around the world because of climate change, ocean acidification and human interference. But lots of people are also trying to save coral reefs before it’s too late. Here’s a roundup of some of the latest research into this important class of organism.

Some of the worst news comes out of Indonesia, where the Wildlife Conservation Society (WCS) found that rising surface water temperatures have created a large-scale bleaching event in the local coral. Bleaching occurs when environmental factors stress the living organisms residing within coral reefs, causing them to either leave their reef structures or die. As a result, reefs turn white. WCS marine biologists found that at least 60 percent of the area’s coral reefs, and 80 percent of some coral species in the region, have bleached and died following a 4-degree Celsius rise in water temperatures. Bleached coral reefs cannot support the variety of marine life that depend on coral for their survival. That, in turn, affects the ability of people to fish for their livelihoods around those reefs.

Meanwhile, those warm waters from Southeast Asia are heading into the North Pacific, with Hawaii as their likely next destination. Scientists from Papahanaumokuakea Marine National Monument are monitoring Hawaii’s coral reefs for any signs of bleaching. (Scientists from Papahanaumokuakea also recently discovered what they believe could be ten new species of coral in Hawaii.)

Warm water isn’t the only threat to coral. Acidic waters, caused by a buildup of carbon dioxide, are becoming a greater problem as the oceans absorb excess CO2 from the air, a side effect of climate change. According to John Guinotte, a coral specialist at the Marine Conservation Biology Institute in Bellevue, Wash., the oceans today are 30 percent more acidic than they were at the time of the Industrial Revolution. This rise presents a danger to coral, which build their skeletons out of calcium carbonate, a substance that does not respond well to low pH levels. “A reduction in carbonate ions not only impedes corals’ ability to build their skeletons, but once the calcium carbonate drops below critical levels, the ocean erodes the framework they have built up previously—the reefs upon which corals live,” Guinotte told The Guardian.

Shipping also poses multiple threats to coral. In incidents just eight days apart, vessels collided with reefs off India’s coast, spilling oil and damaging the reefs. “These reefs have over 150 species of coral, 600 species of mollusc, 1,000 species of fish, 150 species of marine algae and a plethora of flora and fauna,” Deepak Apte of the Bombay Natural History Society told The Times of India.

Another threat to coral: illegal trade. Fiji’s Fijivillage newspaper has an investigative report into the poaching there and how pervasive it has become.

With all of this going on, scientists are working on ways to preserve coral and keep it from extinction. For example, a team of scientists from the Smithsonian Institution and the Hawaii Institute of Marine Biology has created a frozen “bank” of Hawaiian corals. They have started with frozen sperm and embryonic cells from mushroom coral (Fungia scutaria) and rice coral (Montipora capitata) and hope to include many other coral species as the project progresses. Meanwhile, in Florida, scientists and volunteers have resorted to raising coral in ten nurseries, with the hope of repopulating depleted reefs in the region.

And in a key bit of research news, scientists from the Australian Research Council Centre of Excellence for Coral Reef Studies have come up with a clue that might help us to understand why some coral bleach and die and others do not. It seems it all depends on how much energy a species devotes to immunity. “As energy is vital for an effective immune response, corals that utilize energy to grow and reproduce rapidly have less to spare for their immune response,” one of the scientists, Caroline Palmer, said in a prepared statement released last week. “These corals, like the staghorns, Acropora, are the colonies most vulnerable when challenged by temperature stress or disease.”

Finally, here’s a bit of good news: researchers studying the Arno atoll in the Marshall Islands have found what could be the world’s rarest coral, Pacific elkhorn coral (Acropora rotumana), which had not been seen in more than 100 years. No word yet on what threats it will face in the future.

Photo: Bleached coral in Aceh, Indonesia. Courtesy of the Wildlife Conservation Society.

 





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