Human sewage killing coral
Washington - Human sewage is to blame for a disease that is killing elkhorn coral, listed as endangered several years ago because of a massive die-off, US researchers said.
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 analysed the bacteria from a wastewater treatment facility in Key West, Florida and compared to faeces samples from local animals and birds. The type afflicting coral was found to match the kind found in human sewage.
In the study published in the peer-reviewed journal PLoS ONE on Wednesday, researchers described their finding as "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," said co-author James Porter of the University of Georgia.
Serratia marcescens can cause a host of infections in humans, ranging from respiratory to urinary to skin, and has been linked to meningitis and pneumonia.
"Bacteria from humans kill corals - that's the bad news," said Porter. "But the good news is that we can solve this problem with advanced wastewater treatment facilities" like one recently completed in the tourist haven of Key West.
The entire surrounding area in south Florida is upgrading its wastewater treatment plants, which should block the bacteria from reaching to open ocean, the study said.
The National Oceanic and Atmospheric Administration 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.
Disease, pollution, predation, warmer water temperatures and storms have contributed to population losses of 75% to 95% of the coral since 1980, NOAA said.