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Biologically–induced elemental variations in Antarctic sandstones: a potential test for Martian micro-organisms

Blackhurst, Rebecca L.; Jarvis, Kym and Grady, Monica M. (2004). Biologically–induced elemental variations in Antarctic sandstones: a potential test for Martian micro-organisms. International Journal of Astrobiology, 3(2) pp. 97–106.

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DOI (Digital Object Identifier) Link: http://dx.doi.org/10.1017/S147355040400206X
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Abstract

Lichen-dominated cryptoendolithic communities from the Dry Valleys of Antarctica have been the subject of much research over recent years owing to their potential as analogues of Martian life forms. Their ability to mobilize iron compounds and organize themselves into distinct coloured biotic zones suggests that they may alter the chemistry of their host rock. By conducting a major, minor and trace element study utilizing inductively coupled plasma atomic emission spectroscopy (ICP-AES) and mass spectrometry (ICP-MS) techniques, we have been investigating the relationship between the microbes and the chemistry of the sandstones. Different layers within a suite of sandstones collected from six localities in the Dry Valleys have been analysed to establish if or how the microbes influence or directly affect the chemical composition of the rocks. Background petrographic studies have shown significant differences in mineralogical maturity between rocks colonized by the communities and those that are not, and the chemistry results have shown significant elemental disparity between colonized and uncolonized rocks. By obtaining accurate percentages of the minerals present in each sample the differences in elemental concentrations could be construed to be caused by the differences in mineralogy between samples. The nature and extent of the concentration differences has led to the conclusion that either the cryptoendolith communities are able to alter their host rock by the solubilization and mobilization of elements that are then subsequently removed or that the organisms are simple opportunists that can only successfully colonize rocks that provide the ideal substrate, being mineralogically mature with ample pore space and less concentrated in the elements tested for.

Item Type: Journal Article
ISSN: 1473-5504
Extra Information: The original publishers version is available at http://journals.cambridge.org/
Keywords: Antarctic dry valleys; cryptoendolithic lichens; oxalic acid; analogues of Martian life-forms; sandstone chemistry.
Academic Unit/Department: Science > Physical Sciences
Interdisciplinary Research Centre: Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
Item ID: 8051
Depositing User: Kyra Proctor
Date Deposited: 13 Jun 2007
Last Modified: 02 Apr 2011 01:48
URI: http://oro.open.ac.uk/id/eprint/8051
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