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2008 Annual Science Report

Indiana University, Bloomington Reporting  |  JUL 2007 – JUN 2008

Microbial Communities in Subpermafrost Saline Fracture Water at the Lupin Au Mine, Nunavut, Canada

Project Summary

As scientists prepare to search for life in the subsurface of Mars, it is increasingly clear that we have little experience characterizing microbial life in permafrost environments on Earth. Lupin gold mine in Nunavut Territory Canada provides scientists with an opportunity to collect samples of ground water beneath 500 meters of permafrost. These subpermafrost water samples contain extant microbial communities that are dominated by sulfate-reducing bacteria. It remains to be determined how and when this microbial community became established.

4 Institutions
3 Teams
0 Publications
0 Field Sites
Field Sites

Project Progress

Microbial Communities in Subpermafrost saline fracture water at the Lupin Au Mine, Nunavut, Canada

If subsurface life exists on Mars it does so beneath a few kilometers of permafrost. Similar environments on Earth have not been characterized due to their inaccessibility. Lupin Au Mine provided an opportunity to collect samples of fracture water beneath 500 meters of permafrost to determine whether the extant microbial communities were similar to those found in South Africa. Gross phylogenetic similarities were recognized in terms of the dominance of sulfate reducing bacteria, but methanogens were strangely absent. These sulfate-reducing bacteria likely colonized the sub-permafrost during the Pleistocene; whereas aerobic bacteria may have entered the fracture water networks either during deglaciation prior to permafrost formation 9,000 years BP or from the nearby talik through the hydrologic gradient created during dewatering of the mine.

Detailed thermodynamic analyses of the fracture water chemistry combined with a hydrological and microbial model revealed that the methanogens were likely excluded from the subpermafrost environment due to a high pH-induced, energy bottle-neck. A manuscript describing the geochemistry and microbiology of the Lupin Au mine has been submitted to Microbial Ecology. Because underground mining activity at Lupin Au mine has been terminated, we no longer have access to this wonderful window into the subpermafrost biosphere.

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    Tullis Onstott Tullis Onstott
    Project Investigator
    Lisa Pratt Lisa Pratt
    Project Investigator
    Corien Bakermans
    Terry Hazen Terry Hazen
    Shaun Frape

    Timo Ruskeeniemi

    Randy Stotler

    Objective 2.1
    Mars exploration

    Objective 5.1
    Environment-dependent, molecular evolution in microorganisms

    Objective 5.2
    Co-evolution of microbial communities

    Objective 5.3
    Biochemical adaptation to extreme environments

    Objective 7.1
    Biosignatures to be sought in Solar System materials