|January 22, 1999||Volume 6, Number 9|
U of S geologist tracks microbes in extreme environments
Professor Robin Renaut, a sedimentary geologist in Geological Sciences, considers himself privileged to work "in a dynamic department where, without exception, everyone is involved with research."
His own research - into the role of microbes in mineral precipitation at high temperatures - takes him to exotic locations around the world to seek out geyser and hot-spring activity.
"In what other discipline can you work in Kenya one summer, New Zealand in the February break, and be 4,000 metres up in the Andes the next year?"
While tracking microbes may seem esoteric, Renaut's work has wide scientific implications and, as evidenced by a number of recent honors, including a television production featuring his and colleagues' work, is regarded by some sedimentary geologists as iconoclastic.
"The accepted view until about 20 years ago was that very hot and boiling water in geysers and hot spring vents harbored no life. Microbiologists then discovered bacteria and archea living in boiling waters at Yellowstone. We've shown not only that these environments are teaming with life, but also that the microbes help to build many of the rocks in such settings.
"Moreover, many fossilized microbes found in hot springs, where temperatures can rise over 100°C, resemble the oldest known fossils and consequently provide clues to the origins of life on earth."
For a paper written on the subject, "Biogenicity of silica precipitation around geysers and hot-spring vents, North Island, New Zealand," Renaut and colleagues Brian Jones (University of Alberta) and Michael Rosen (Institute of Geological and Nuclear Sciences, Taupo, New Zealand), were recently awarded the Outstanding Paper for 1997 in the Journal of Sedimentary Research. Their paper was selected from over 150 published in the international journal during the year.
Their work will also feature in a TV documentary on the origin of life, to be shown worldwide on the Discovery channel later this year. It was filmed last summer at the Waiotapu hot springs in New Zealand.
"If the experience taught us anything, it's that it takes about five hours of filming to provide five minutes of footage. We had to walk through steam carrying our equipment a number of times, because the steam kept blowing towards the camera. These particular hot springs are a favorite holiday spot in New Zealand. We were approached by tourists asking us what we were doing, which sometimes made it difficult to attend to the matter at hand. But on the whole, it was good fun."
Renaut came to the U of S in 1983, after graduating from the University of London with a PhD. His early field work, providing a geological interpretation of early hominid sites, was done in East Africa with, among others, famed paleoanthropologist Richard Leakey.
He says the area around Lake Baringo, in Kenya, is of great interdisciplinary interest and the location of an ongoing project he's undertaking with colleagues from the Universities of Connecticut and Yale.
"The rift sediments in the Baringo area contain fossil hominids and archaeological sites that reveal several stages in human evolution. Studying the geochemistry and mineralogy of these sedimentary rocks is providing important clues to the changing environments in which human evolution took place."
Renaut, who has also done extensive geological studies of the sediments to be found in British Columbia's salt lakes, particularly those in the Cache Creek area, supervises a number of graduate students whose applied research has practical implications for the potash industry in Saskatchewan.
"The highly saline waters in which potash formed contained microbes somewhat similar to those in hot springs. These microbes are extremophiles - i.e., organisms that live under conditions of extreme heat, cold, pressure or salinity. Now that bacteria have also been discovered living in rock several kilometers below the earth's surface, geologists will have to revise their thinking. In 10 years, I'm sure our textbooks will have to be altered to reflect these changes."
He says other extremophile discoveries that are rocking the geological world include the 1996 claim by NASA scientists of the existence of "nanobacteria" (in a meteorite from Mars) that are as much as 10 times smaller than normal bacteria.
"Only with further research will it be confirmed if nanobacteria are true or mere appendages to bacteria, perhaps. The microbes from the meteorite could be mineral crystals. Morphologically, they can look alike. It is taking a fusion of disciplines - microbiologists, geochemists, sedimentologists - to interpret the data."
Academic controversies aside, however, some geological research is not work for the faint of heart. Working in Kenya a few years ago, Renaut stepped in boiling water when a hot-spring rim gave way, and he has scalded his hands several times.
"When you do this work on a daily basis, you forget the dangers and tend to become over-confident."
He's also been spat at by a cobra and chased by an elephant in Kenya.
"But usually it's the smaller hazards, such as scorpions, poison snakes, and insects, that one has to be concerned with."
Working in stagnant water can cause such diseases as bilharzia, a potentially fatal liver ailment caused by a blood fluke that can take many years after contraction to manifest itself. And, he adds, scientists who work in geothermal areas have to be concerned about dangerous gases.
"Hydrogen sulfide, as everyone knows, smells like rotten eggs, so usually we can sense it at very low levels. But there's always the danger of inhaling too much, so that one's sense of smell disappears. At some hot springs in New Zealand, you should really wear breathing apparatus, and even then there are areas too dangerous to enter."
He's also had malaria, which he used the controversial drug Larium to treat.
"French geologists I work with won't touch it, but in Canada it's still recommended. I've had no adverse reactions but I don't have options. In most of the areas I work in East Africa there is resistance to other malarial drugs."
Despite the dangers and after he and his colleagues pick up their prize for best paper at the AGM of the Society for Sedimentary Geology in San Antonio next April, Renaut will be back on the trail of hot springs and hominids in Tanzania and Kenya next summer. And who knows? Ideas about the very origin of life could be revised by what he and his colleagues find.
- Sigrid Klaus
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