New Dangerous Viruses & Bacteria Showing Up In Warming Oceans
ANAHEIM, Calif. (AP) -- Previously unknown bacteria and viruses blooming in the Earth's warming oceans are killing some marine life and threatening human health, researchers say.
There are increasing reports of dying coral, diseased shellfish and waters infected with human viruses as the seas rise in temperature and pollution from the land intensifies, researchers said Friday in studies presented at the national meeting of the American Association for the Advancement of Science.
"These are the cries and whispers beginning to confront us about the ecological dangers ahead," said James Porter, an ocean studies specialist at the University of Georgia. "We are finding disturbing new kinds of things." About 10 per cent of the coral worldwide has died, said Porter, and if present trends and conditions continue, another 20 to 30 per cent of the coral could be lost.
In many cases, he said, the pathogens -- viruses, bacteria and fungi -- killing the coral had not been previously identified by researchers. "Corals are like the canary in the mine," said Porter. "They are telling us that the water where they live is becoming suboptimal for their existence."
There has been a 446 per cent increase in disease at 160 coral sites being monitored along the Florida coast since 1996. One reef experienced a death rate of 62 per cent, said Porter, and nearly all of the killing pathogens "are new to science."
"We don't know if what we are seeing is a natural cycle or it is being caused by what human beings are doing to the planet," he said. Porter said the loss of coral is significant because the reef-building animal "is the basis for the health of the tropical seas."
New studies show that vast colonies of human viruses migrate regularly into coastal waters of Florida from the 1.6 million septic tanks in the state, said Joan Rose, a University of South Florida researcher.
Many people are becoming infected with viruses picked up while swimming, windsurfing or boating in infected waters. One study found that almost a quarter of the people using marine beaches develop ear infections, sore throats and eyes, respiratory or gastrointestinal disease.
Some of the viruses detected in coastal waters are linked with heart disease, diabetes, meningitis and hepatitis.
"Most people who come in contact with these viruses do not get ill," she said. But of the 20 to 24 per cent who do, about one per cent become chronically infected, she said.
Rose's research team has traced the migration of viruses from septic tanks and found that the pathogens infect coastal waters within 24 hours of being flushed down toilets. Storms that churn the waters and set up currents can speed the process and cause an even wider spread.
Viruses have been detected in oysters and other shellfish in many coastal areas outside of Florida. For instance, some sampling in New York waters has found 40 per cent of the shellfish infected.
Wounds infected with waterborne viruses caused two deaths and five hospitalizations in 1995 along the Mississippi coast of the Gulf of Mexico, Rose said. And more than a third of water samples from Waikiki Beach in Hawaii were found in one study to be infected with human viruses.
Many of the disease-causing viruses that infect humans directly or through eating contaminated shellfish cannot be detected by the routine monitoring of water pollution, said Rose.
Porter said the increase in pathogens in the world's oceans may be linked to a rises in sea surface temperature detected in many areas. He blamed the warming oceans, for instance, for "a very distinctive global pattern of coral bleaching."
The warmer water kills algae living on the coral, weakening the coral and making it more susceptible to infection.