The Heat Is Online

Warming Oceans Threaten Human Health

As Oceans Warm, Problems From Viruses and Bacteria Mount

The New York Times Jan. 24, 1999


ANAHEIM, Calif. -- 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' temperature rises and pollution from the land intensifies, researchers said on 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 W. Porter, an ocean studies specialist at the University of Georgia. "We are finding disturbing new kinds of things."

About 10 percent of the coral worldwide has died, Porter said, and if current trends and conditions continue, an additional 20 percent to 30 percent 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," Porter said. "They are telling us that the water where they live is becoming suboptimal for their existence."

There has been a 446 percent increase in disease at 160 coral sites being monitored along the Florida coast since 1996. One reef had a death rate of 62 percent, Porter said, 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 was 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 B. 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 developed ear infections, sore throats and eyes, respiratory or gastrointestinal disease.

Some of the viruses detected in coastal waters are linked to heart disease, diabetes, meningitis and hepatitis.

"Most people who come in contact with these viruses do not get ill," Ms. Rose said. But of the 20 percent to 24 percent who do, about 1 percent become chronically infected, she said.

Ms. 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 can speed the process.

Viruses have been detected in oysters and other shellfish in many coastal areas outside Florida. For instance, some sampling in New York waters has found 40 percent of the shellfish infected.

Many of the viruses that infect humans directly or through eating contaminated shellfish cannot be detected by the routine monitoring of water pollution, Ms. Rose said.

Porter said the increase in pathogens in the world's oceans might be linked to a 1.8 degree rise in sea surface temperature detected in many areas. He blamed the warming oceans, for instance, for a "global pattern of coral bleaching." The warmer water kills algae on the coral, weakening the coral and making it more susceptible to infection.

Copyright 1999 The New York Times Company