Microbial origin of excess methane in glacial ice and implications for life on Mars
Methane trapped in the 3,053-m-deep Greenland Ice Sheet Project 2 ice core provides an important record of millennial-scale climate change over the last 110,000 yr. However, at several depths in the lowest 90 m of the ice core, the methane concentration is up to an order of magnitude higher than at...
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ftpubmed:oai:pubmedcentral.nih.gov:1308353 2023-05-15T16:29:38+02:00 Microbial origin of excess methane in glacial ice and implications for life on Mars Tung, H. C. Bramall, N. E. Price, P. B. 2005-12-20 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1308353 http://www.ncbi.nlm.nih.gov/pubmed/16339015 https://doi.org/10.1073/pnas.0507601102 en eng National Academy of Sciences http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1308353 http://www.ncbi.nlm.nih.gov/pubmed/16339015 http://dx.doi.org/10.1073/pnas.0507601102 Copyright © 2005, The National Academy of Sciences Physical Sciences Text 2005 ftpubmed https://doi.org/10.1073/pnas.0507601102 2013-08-30T18:18:23Z Methane trapped in the 3,053-m-deep Greenland Ice Sheet Project 2 ice core provides an important record of millennial-scale climate change over the last 110,000 yr. However, at several depths in the lowest 90 m of the ice core, the methane concentration is up to an order of magnitude higher than at other depths. At those depths we have discovered methanogenic archaea, the in situ metabolism of which accounts for the excess methane. The total concentration of all types of microbes we measured with direct counts of Syto-23-stained cells tracks the excess of methanogens that we identified by their F420 autofluorescence and provides independent evidence for anomalous layers. The metabolic rate we estimated for microbes at those depths is consistent with the Arrhenius relation for rates found earlier for microbes imprisoned in rock, sediment, and ice. It is roughly the same as the rate of spontaneous macromolecular damage inferred from laboratory data, suggesting that microbes imprisoned in ice expend metabolic energy mainly to repair damage to DNA and amino acids rather than to grow. Equating the loss rate of methane recently discovered in the Martian atmosphere to the production rate by possible methanogens, we estimate that a possible Martian habitat would be at a temperature of ≈0°C and that the concentration, if uniformly distributed in a 10-m-thick layer, would be ≈1 cell per ml. Text Greenland Greenland Ice Sheet Project ice core Ice Sheet PubMed Central (PMC) Greenland Proceedings of the National Academy of Sciences 102 51 18292 18296 |
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Physical Sciences Tung, H. C. Bramall, N. E. Price, P. B. Microbial origin of excess methane in glacial ice and implications for life on Mars |
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Physical Sciences |
description |
Methane trapped in the 3,053-m-deep Greenland Ice Sheet Project 2 ice core provides an important record of millennial-scale climate change over the last 110,000 yr. However, at several depths in the lowest 90 m of the ice core, the methane concentration is up to an order of magnitude higher than at other depths. At those depths we have discovered methanogenic archaea, the in situ metabolism of which accounts for the excess methane. The total concentration of all types of microbes we measured with direct counts of Syto-23-stained cells tracks the excess of methanogens that we identified by their F420 autofluorescence and provides independent evidence for anomalous layers. The metabolic rate we estimated for microbes at those depths is consistent with the Arrhenius relation for rates found earlier for microbes imprisoned in rock, sediment, and ice. It is roughly the same as the rate of spontaneous macromolecular damage inferred from laboratory data, suggesting that microbes imprisoned in ice expend metabolic energy mainly to repair damage to DNA and amino acids rather than to grow. Equating the loss rate of methane recently discovered in the Martian atmosphere to the production rate by possible methanogens, we estimate that a possible Martian habitat would be at a temperature of ≈0°C and that the concentration, if uniformly distributed in a 10-m-thick layer, would be ≈1 cell per ml. |
format |
Text |
author |
Tung, H. C. Bramall, N. E. Price, P. B. |
author_facet |
Tung, H. C. Bramall, N. E. Price, P. B. |
author_sort |
Tung, H. C. |
title |
Microbial origin of excess methane in glacial ice and implications for life on Mars |
title_short |
Microbial origin of excess methane in glacial ice and implications for life on Mars |
title_full |
Microbial origin of excess methane in glacial ice and implications for life on Mars |
title_fullStr |
Microbial origin of excess methane in glacial ice and implications for life on Mars |
title_full_unstemmed |
Microbial origin of excess methane in glacial ice and implications for life on Mars |
title_sort |
microbial origin of excess methane in glacial ice and implications for life on mars |
publisher |
National Academy of Sciences |
publishDate |
2005 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1308353 http://www.ncbi.nlm.nih.gov/pubmed/16339015 https://doi.org/10.1073/pnas.0507601102 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Greenland Ice Sheet Project ice core Ice Sheet |
genre_facet |
Greenland Greenland Ice Sheet Project ice core Ice Sheet |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1308353 http://www.ncbi.nlm.nih.gov/pubmed/16339015 http://dx.doi.org/10.1073/pnas.0507601102 |
op_rights |
Copyright © 2005, The National Academy of Sciences |
op_doi |
https://doi.org/10.1073/pnas.0507601102 |
container_title |
Proceedings of the National Academy of Sciences |
container_volume |
102 |
container_issue |
51 |
container_start_page |
18292 |
op_container_end_page |
18296 |
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1766019345124687872 |