August 18, 2011

Human Waste Killing Off Endangered Coral

US researchers said on Wednesday that human sewage is causing a disease that is killing elkhorn coral.

This coral was listed as endangered several years ago due to a massive die off.  The coral lives in waters off south Florida and the Bahamas and was once the most prevalent in the Caribbean but has been vanishing due to white pox disease, caused by the bacterium Serratia marcescens that is found in human and animal waste.

Researchers analyzed bacteria from a wastewater treatment facility in Key West, Florida and compared it to feces samples from local animals and birds.

This bacteria afflicting the coral was also found in human sewage.

Researchers said their finding was "the first time a human disease has been shown to cause population declines of a marine invertebrate."

"These bacteria do not come from the ocean, they come from us," co-author James Porter of the University of Georgia said in a press release.

Serratia marcescens has been linked to meningitis and pneumonia and can cause several types of infections in humans.

"Bacteria from humans kill corals -- that's the bad news," Porter said in a press release. "But the good news is that we can solve this problem with advanced wastewater treatment facilities."

"This problem is not like hurricanes, which we can't control. We can do something about this one," he said in a press release.

The study said the entire surrounding area in south Florida is upgrading its wastewater treatment plants, which should block the bacteria from reaching to open ocean.

The National Oceanic and Atmospheric Administration (NOAA) says it has been "one of the three most important Caribbean corals contributing to reef growth and development and providing essential fish habitat" over the past 10,000 years.

NOAA said that disease, pollution, predation, warmer water temperatures and storms have helped cause the population losses of 75 to 95 percent of the coral since 1980.

The study was published in the journal PLoS ONE.


Image 1: Disease-free coral colonies are rare during a white pox disease outbreak, but some colonies (such as those shown here from Molasses Reef) may have natural resistance to this bacterium and may live to recolonize the reef. This cycle of infection and recovery places a premium on maintaining good water quality on the reef so that surviving colonies can regrow quickly. Credit: James W. Porter, University of Georgia

Image 2: White pox disease on a frond of the endangered elkhorn coral on Carysfort Reef in the Florida Keys. White pox disease comes from humans, but when it infects coral, as in this case from the Upper Keys, it causes white blotches by killing the overlying coral tissue and revealing the coral's white limestone skeleton underneath. Credit: James W. Porter, University of Georgia


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