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2005 Annual Science Report

University of Colorado, Boulder Reporting  |  JUL 2004 – JUN 2005

Molecular Survey of Microbial Diversity in Hypersaline Ecosystems

4 Institutions
3 Teams
0 Publications
0 Field Sites
Field Sites

Project Progress

In the main area of research, microbiology of hypersaline ecosystems, substantial progress was made. ~4000 new rRNA sequences were determined and thereby organisms were identified from hypersaline situations: microbial mat and crystallizing halite-gypsum (brine). Many new bacterial and archaeal clades were discovered, including ~15 new bacterial phylogenetic divisions (“kingdoms”). Surprisingly, cyanobacteria do not constitute the main biomass (rRNA gene content), rather, Green Nonsulfur Bacteria dominate numerically. This has implications for the interpretation of isotopic fractionation data. Numerous novel eucaryotes also were found. Most of the eucaryotic biomass resides with nematodes, abundant in this ecosystem. Several publications are being prepared based on findings.

In a second area of work, the biology of high-temperature ecosystems, we have completed analysis of Yellowstone systems >70°C. Notably, organisms identified molecularly as hydrogen-metabolizing constitute the most common life in those hot springs. We have now measured molecular hydrogen in a number of Yellowstone hot springs and find abundant hydrogen for metabolism (15-300 nM). Also in Yellowstone we have discovered and described a new form of endolithic community, in silica sinter perfused with volcanic gases inluding hydrogen sulfide, which results in low pore water pH (<1). The community is lichen-like, but the photobiont is the organism Cyanidium caldarium and a supporting filamentous comunity is comprised of unidentified mycobacteria, never previously seen in such conditions. The communities are rapidly encased in silica and thereby provide long-lived traces of past life that could be examples of important biosignatures on, e.g. Mars.

    Norman Pace Norman Pace
    Project Investigator
    Thomas McCollom

    Dominic Papineau

    Ruth Ley

    John Spear

    J. Harris
    Doctoral Student

    Jeffrey Walker
    Doctoral Student

    Alicia Berger
    Undergraduate Student

    Objective 3.2
    Origins and evolution of functional biomolecules

    Objective 3.4
    Origins of cellularity and protobiological systems

    Objective 4.1
    Earth's early biosphere

    Objective 4.2
    Foundations of complex life

    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 6.1
    Environmental changes and the cycling of elements by the biota, communities, and ecosystems

    Objective 6.2
    Adaptation and evolution of life beyond Earth

    Objective 7.2
    Biosignatures to be sought in nearby planetary systems