Ruth Henneberger
Diplom Biologin, University of Regensburg, Germany

PhD Student

Research Area:
Identification of extremophiles in acidic hydrothermal environments

My interest in extremophiles started during my studies of Biology at the University of Regensburg, Germany. The research that was done by Prof. K.-O. Stetter and Prof. Robert Huber at the “Centre for Archaea” at this University was so fascinating to me that I decided to concentrate my studies on extreme microorganisms.

After graduating in microbiology and spending 6 months as an intern at Spirig Pharma AG, Switzerland, I returned to the University of Regensburg. During my 12 months honours project together with Prof. Huber’s research group I worked on the archaeal partner of a unique microbial community in cold sulfidic springs close to Regensburg.

I finished this project at the end of 2002 and escaped from cold and rainy Germany in February 2003 to start an internship at the Australian Centre for Astrobiology. Together with my supervisor Dr. Roberto Anitori I was working on the microbial diversity of a radon-containing hot spring in South Australia and water of the Great Artesian Basin. The short stay in Australia, which was originally planned for 8 months, turned into a 4-year student visa and an iMURS (International Macquarie University Scholarship). I started my PhD at the ACA in February 2004 under the supervision of Dr. Roberto Anitori and Prof. Malcolm Walter.

Although volcanoes are important emitters of sulfur dioxide and microorganisms in hydrothermal areas are often responsible for sulfur and iron cycling, it is still unclear exactly how these elements are cycled and utilized by the microbes residing in volcanic regions. Identification and description of the microorganisms inhabiting hydrothermal environments, together with chemical and physical data, therefore provide important insights into geomicrobiological processes. Furthermore, modern hydrothermal systems are considered good analogues for conditions on the early Earth. Description of the microbial ecology of hydrothermal environments is therefore also important in the search for the origin of life on Earth, a key goal of the field of Astrobiology.

In the summit region of the Mt. Hood volcano ( Cascade Range, USA) hydrothermal heat and sulfur-rich volcanic steam have formed a unique extreme environment with a local microclimate, surrounded by permanent glacial ice and snow. Devil’s Kitchen and Hot Rock are two hydrothermal fields on Mt. Hood that are characterised by numerous steaming fumaroles, extensive sulfur deposits, no vegetation and a high flux of UV radiation. Very little is known about the microbial ecology of this particular environment and no microbiological study has been published. The remote location at high altitude (about 3200 m) off the main climbing route to the summit protects the Devil’s Kitchen and Hot Rock areas from contamination. Therefore, microbiological studies of this hydrothermal area would reflect the natural state of the microbial communities present in this remarkable environment. The major aim of this thesis project is to obtain a detailed description of the diversity and ecology of extremophilic microorganisms inhabiting acidic hydrothermally altered andesitic and dacitic fumarolic fields. This will provide insights into the geomicrobiological processes and roles that these microbes may have in the cycling of geologically important sulfur and iron compounds.

In August 2004 and July 2005 samples of hot (up to 89 ºC) acidic (pH 1-3) hydrothermally altered soil, gravel and rocks were collected from the Devil’s Kitchen and Hot Rock fumarolic fields. Culturing of microorganisms, different microscopic techniques and molecular biological methods such as analyses of 16S rRNA sequences and FISH (Fluorescent In Situ Hybridisation) are currently performed to investigate the microbial diversity present in this remarkable environment. Different thermoacidophilic representatives of both prokaryotic domains (bacteria and archaea) were detected in small numbers within the hydrothermally heated soils of Mt. Hood. The organisms identified so far are commonly found in bioleaching environments and are known to be involved in Acid Mine Drainage. They also play an important role in biogeochemical cycling of sulfur and sulfide metals.

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Last Updated: Jan 30 2006