Todd Stevens
Consulting Scientist
Geomicrobiology
Field
and Laboratory Research
My current research focuses on microorganisms in soils
and aquifers and their interactions with igneous minerals and other phenomena
in their environment.
Current Projects:
Mars Astrobiology Research and Technology Experiment (MARTE): A
Mars Analog Drilling Project on the Rio Tinto, Spain.
Sponsor: NASA "Astrobiology Science and Technology for Exploring Planets"
(ASTEP) Program
This is a multi-institution project led by NASA Ames Research Center. Remotely-operated
drilling and sampling equipment designed for Mars exploration is being used
to explore Earths subsurface biosphere. Conventional drilling equipment
and manual sample handling complement this effort. In conjuction with
Spains Centro de Astrobiology, we are exploring the subsurface of the Rio
Tinto drainage in southwestern Spain. This is one of the largest pyrite
ore bodies on Earth. We are testing the hypotheses that subsurface
microbes there grow autotrophically and are independent of surface biology.
Natural springs in the area emit extremely acidic, iron-and sulfate-rich
waters similar to acid mine drainage, and are presumably influenced by subsurface
microbial metabolism.
This project has an
opening for a Ph.D. Graduate Student. Please contact me for more information.
Microbial Interactions with Reduced Minerals: A system
for early terrestrial and extraterrestrial life
Sponsor: NASA Exobiology Program
In this project, I am using laboratory microcosms to test
several hypotheses about microbial ecosystems in deep aquifers within igneous
rock formations. The overall hypothesis is that anaerobic microorganisms
are able to carry out primary production in the deep subsurface using energy
released during the weathering of igneous rocks. If so, this means that
microbial ecosystems could exist that are not dependent upon photosynthesis.
Such ecosystems could thrive in the deep subsurface and potentially on other
planets where the surface environment is hostile to life.
We have sometimes referred to this idea as The SLME Hypothesis.
Graduate
Assistantships available to study the Subsurface Biosphere
at Oregon State University and Portland State University
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tstevens@gorge.net