According to Jill Banfield, the leader of the scientific team behind the discovery, "This takes the study of natural biogeochemical systems to a new level."

Announced Feb. 1 in the online version of the journal Nature, the research focused on a sample from a postagestamp- sized patch of pink biofilm taken from a thin microbial layer found growing hundreds of feet underground. (Often slimy, biofilms are communities of microorganisms-such as bacteria and fungi-that grow on surfaces. Think of a kitchen sink left unwiped.) The research team found its biofilm atop a hot, flowing, extremely acidic solution-laden with dissolved iron, copper, zinc and arsenic-emanating from a mine on Iron Mountain, about nine miles northwest of Redding.

According to the Environmental Protection Agency, the mine, which shut down in 1963 after nearly a century of operations, created the most acidic mine drainage in the world, discharging-on average-a ton of toxic metals every day into the Upper Sacramento River until remediation efforts began a decade ago.

Acid mine drainage remains a significant environmental problem worldwide. Banfield, a professor at the University of California at Berkeley, said the new findings enhance scientists' understanding of the metabolic activity of iron oxidizing microbes that greatly accelerates acid production.

Nine other scientists from Berkeley and the Department of Energy's Joint Genome Institute in Walnut Creek, Calif., co authored the report. The study was funded by the National Science Foundation's Biocomplexity in the Environment program and the Department of Energy's Microbial Geno
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Contact: Sean Kearns
skearns@nsf.gov
703-292-7963
National Science Foundation
1-Feb-2004