Bleached Corals May Have Herpes
Viruses may play a role in coral bleaching events, a new study finds. Continue reading →
Scientists have found that a surprising organism may sometimes be present when coral reefs undergo devastating bleaching events: a form of herpes virus.
In a recent paper in the journal Frontiers in Microbiology, researchers from Oregon State University describe how, while they were studying corals on Australia's Great Barrier Reef, a bleaching event began to take place. The researchers took samples of the bleaching corals and of the surrounding water, and found that the viral loads in the corals had exploded to levels 2-4 times higher than ever recorded in corals. The viruses included retroviruses and megaviruses; a type of herpes virus was particularly abundant.
It might seem surprising to think of viruses in the context of coral reefs. But in fact marine viruses are by far the most abundant lifeforms in the ocean -- if one does consider them lifeforms, a subject of some scientific controversy. Approximately 1023 viral infections occur in the sea every second, and the approximately 1030 viruses in the ocean, if placed end to end, would span farther than the nearest 60 galaxies.
And while we may associate herpes with cold sores and awkward conversations with potential partners, herpes viruses are ancient and are found in a wide range of mammals, marine invertebrates, oysters, corals and other animals. (However, while part of the same family, herpes viruses that affect corals do not infect humans, and vice-versa.)
However, the researchers could not confirm whether the viral outbreak caused the bleaching, was a consequence of it, or took place simultaneously.
"It's a total chicken and the egg question," Rebecca Vega-Thurber, an assistant professor of microbiology in the OSU College of Science and corresponding author on the study, told Quartz. "Did the bleaching event induce viral production, or did stress induce viruses which help induce bleaching? They're probably going on at the same time."
Indeed, the specific proximate causes of bleaching -- so-called because corals expel the symbiotic algae that live within them and give them their color -- remain uncertain, although some combination of environmental stresses certainly plays a part. The most significant appears to be increased water temperature, but others can include pollution and overfishing. The latest study suggests that, as with humans, being under stress can render corals more susceptible to infection.
"This is bad news," Vega-Thurber said. "This bleaching event occurred in a very short period on a pristine reef. It may recover, but incidents like this are now happening more widely all around the world."
Last year, NOAA declared that the world was now experiencing its third global coral bleaching event, the previous two being in 1998 and in 2010. The current event began in the northern Pacific Ocean in 2014, moved south during 2015, and may continue into this year, NOAA officials said.
"People all over the world are concerned about long-term coral survival," Vega-Thurber said. "This research suggests that viral infection could be an important part of the problem that until now has been undocumented, and has received very little attention."
A major coral bleaching event took place on this part of the Great Barrier Reef in Australia.
The month of June honors both National Ocean Month and World Ocean Day (June 8). What better time, then, to check out photos of undersea life and be reminded that things "down there" are just as important as things up here on land. Here, a manatee goes about its day. The manatee, also known as a "seacow," is an air-breathing herbivore listed as a federally endangered species. Manatees are slow moving and can't swim quickly away from boats. This often results in collisions that can kill or injure them.
Life's a beach. Mom and her baby elephant seal roll around in the sand in Ano Nuevo Island, Calif.
A humpback whale breaches in the Gulf of the Farallones National Marine Sanctuary, off the coast of California.
A blue rockfish fans for the camera in Monterey Bay National Marine Sanctuary, in California.
A Southern sea otter, aka,
Enhydra lutris nereis
, wonders what all the fuss is about, at South Harbor, Moss Landing, Calif. The World Ocean Day Photo Contest entrant was Submitted by Dr. Steve Lonhart.
A white-lobed sponge brightens up the scenery. It's one of several images of rarely seen deep-sea animals that were captured on camera in Olympic Coast National Marine Sanctuary during a NOAA expedition. Researchers used a NOAA remotely operated vehicle in waters 328 to 656 feet deep off the Olympic Peninsula in Washington State. The research was funded by NOAA's Coral Reef Conservation Program.
This image brimming with colorful marine life is from the Pearl and Hermes Atoll. It's a huge oval coral reef within several internal reefs and is the second largest among the six atolls in the Northwestern Hawaiian Islands.
Having no backbone isn't always a bad thing! Just ask any octopus. These boneless invertebrates know how to squeeze into (and out of) many a tight spot. They have three hearts, nine brains and blue blood. (Two hearts send blood to the gills, while the third pumper sends it to the rest of the body.)
Rapture Reef sits within the Northwestern Hawaiian Islands Marine National Monument. The monument encompasses more than 140,000 square miles of ocean and coral reef habitat.
A sea turtle swims off of the Hawaiian islands.
This seal is eager to wriggle its way back to freedom, as divers release it from fishing nets. Marine debris -- such as these nets -- makes a serious impact on its surroundings. From being an eyesore on a beach to injuring marine life or stopping a 400-ton vessel at sea, it causes problems that are difficult to ignore.
Grey matter artwork? Nope! It's a sharknose goby (
) propped up on brain coral in the U.S. Virgin Islands.