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Nasty new bug
thrives in acid, stirs up a mess
Previously unknown organism may play role in toxic mine runoff |
| The bug is a new species of Archaea, a family of microbes that can live at extreme conditions, such as the hot volcanic sulfur vents on the ocean floor. | WASHINGTON, March 9 — A super bug that eats iron and can thrive in the equivalent of battery acid may be a major culprit in causing toxic metal and acid runoff from a California mine, researchers say. |
Edwards said that researchers gathering samples 1,500 feet down in the mine had to wear protective clothing and occasionally suffered burns when water where the microbe lived was splashed onto bare skin. Even though the toxic broth in the mine was lethal to most forms of life, said Edwards, the acid-loving microbe thrives in that environment.
The microbe, called Ferroplasma acidarmanus, is a new species of Archaea, a family of microbes that can live at extreme conditions, such as the hot volcanic sulfur vents at the bottom of the ocean. Edwards said the microbe lives best at a pH of .05, which is about a thousand times more acidic than gastric juices in the human stomach. The microbe grows best in temperatures of about 115 degrees.
Unlike most microbes, she said, the new species lacks a double-walled outer membrane. “It lacks a definite shape,” said Edwards. “It’s rather like a sagging water balloon.” Just how the microbe, not found elsewhere, came to live in the Iron Mountain Mine near Redding, Calif., is unknown. But Edwards said the bug is apparently a major cause of the heavy metal, acid pollution flowing out of the old mine. She said ore for gold, copper and zinc were once extracted from the mine. Leftover minerals provide the food for the Archaea bacteria, and the bug then gives off acid that dissolves the metals. This leads to a high concentration of dissolved metals in the runoff. Edwards said the runoff is extremely toxic to other forms of life.