Microbes a Mile Down
Jeff Mitton
Natural Selections (Appeared September 9th in the Daily Camera)
Microbes seem to be everywhere: in bare mineral soils on the highest mountains, at hot vents on the sea floor, deep in Yellowstone hot springs, and in water seeping into the deepest mines. A new research laboratory is being designed to study life deep underground at the Henderson mine on Berthoud Pass.
Biodiversity, the grand sweep of all forms of life, cannot be appreciated without considering microbes and fungi. For example, most species of plants and animals inhale oxygen and exhale carbon dioxide; they use oxygen to release energy stored in sugar and fat. Most animals deprived of oxygen lose consciousness in a few minutes, and soon die. But many microbes live in environments chronically devoid of oxygen. They have the metabolic machinery to use sulfur, ammonia, and hydrogen the way we use oxygen. In addition, microbes are found living and reproducing in temperatures below zero degrees Centigrade to about 120 degrees Centigrade. Finally, microbes are found in highly acidic solutions and strongly alkaline solutions (pH values from 1 to 12).
CU professors Steve Schmidt and Andy Martin and their research team probed bare mineral soils above 12,000 near CU’s Mountain Research Station, and found forms of microscopic fungi that had never been detected or reported. One group of fungi thrived in the warmth of summer, but could not be found in winter. Another group of fungi proliferated beneath ice and snow, but disappeared in springtime. Although gravel on the high mountains appears to be lifeless, microscopic fungi track the seasons with population flushes and crashes.
CU professor Norm Pace and his colleagues Jeff Walker and John Spear have explored the otherworldly environments of the hot springs in Yellowstone National Park. They noted that submerged rocks had a layer of green one centimeter below the rock surface. The rocks were suffused with hot sulfuric acid, yet they supported a community of photosynthetic microbes. A camera lowered into one of the hot springs revealed a seething layer of molten sulfur 60 feet below the surface of the water. The hot water overlaying the sulfur has no oxygen; many of the microbes in the scathing acid respire with hydrogen instead of oxygen.
A consortium of universities, including the State University of New York at Stony Brook, the Colorado School of Mines, Colorado State University and the University of Colorado, have joined with the Arapaho Project Inc. (a local non-profit promoting science) and Phelps Dodge Inc., which runs the Henderson Mine, to propose that a deep underground science laboratory be constructed in the Henderson Mine on Berthoud Pass. Much of the laboratory will be dedicated to physics experiments. For example, a large cavern will be dug, lined with sensors, then filled with water to create a neutrino trap; bursts of neutrinos mark the birth and death of distant stars.
The new laboratory will support long-term studies of microbial life from the surface to depths of more than one mile. Life deep underground is bizarre and intriguing. For example, the microbes in your stomach can reproduce about every 20 minutes, while thousands of feet underground the same process takes decades. Microbiologists are anxious to determine how deeply the surface soil microbes penetrate the earth, and whether unique life forms are associated with the molybdenum porphyry, the protrusion of igneous rock that brought molybdenum close to the surface. Evolutionary biologists mull the possibilities that ancient lineages of life are preserved in deep fissures, and that life formed not in the seas, but in aquifers heated by volcanic eruptions.
Many people are working hard to establish a new laboratory (see http://nngroup.physics.sunysb.edu/husep/) at the Henderson Mine. If swords can be beaten into plowshares, surely a mine can be transformed into a laboratory.
Jeff Mitton inspects a slime of mineral oxides. The water entering the mine has been anoxic for thousands of years, and it has minerals dissolved in it. When the water encounters oxygen, the minerals are oxidized, and precipitate out of solution.
Photo by Mark Ramirez
Alexis Templeton sampled mineral deposits and microbes.
Photo by Jeff Mitton
Jeff Walker (left) and John Spear (right) used a hand pump to pump water through a filter. The filters were taken back to the laboratories at the University of Colorado and Colorado School of Mines to extract DNA and to identify the microorganisms living in rock fissures a mile below the surface.
Photo by Jeff Mitton