Virus Finding Shakes Theory

Scientists reported last week that the concentration of viruses in a German lake may be up to 10 million times greater than previously thought, a finding that shakes existing views on dynamics of underwater life. Norwegian researchers detected 1.25 billion viruses in about a teaspoonful of water from a West German lake--a level 1,000 to 10 million times greater than prior estimates.

The microscopic viruses are a type that preys on bacteria and is not known to infect animals or humans. They are the smallest living particles yet to be found in river, lake or seawater. The University of Bergen’s Gunnar Bratbak and his colleagues said it had generally been assumed that relatively few viruses inhabit natural, unpolluted water.

But in a study published in the British journal Nature, Bratbak’s team said its examination of water with an electron microscope found otherwise. At levels found in Germany’s Lake Plussee in May, 1988, researchers said viruses could play a key role in keeping bacteria populations in check.