Soil consumption of atmospheric methane: Importance of microbial physiology and diversity
Dissertation (Ph.D.) University of Alaska Fairbanks, 1996 Recently, atmospheric CH$\sb4$ concentration has risen dramatically, apparently due to human activities. Since is CH$\sb4$ is involved in several atmospheric processes that regulate Earth's climate, it is important that we understand the...
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ftunivalaska:oai:scholarworks.alaska.edu:11122/9424 2023-05-15T18:31:03+02:00 Soil consumption of atmospheric methane: Importance of microbial physiology and diversity Gulledge, Jay Michael 1996 http://hdl.handle.net/11122/9424 unknown http://hdl.handle.net/11122/9424 Ecology Microbiology Biogeochemistry Dissertation phd 1996 ftunivalaska 2023-02-23T21:37:16Z Dissertation (Ph.D.) University of Alaska Fairbanks, 1996 Recently, atmospheric CH$\sb4$ concentration has risen dramatically, apparently due to human activities. Since is CH$\sb4$ is involved in several atmospheric processes that regulate Earth's climate, it is important that we understand the factors that control its atmospheric concentration. One such factor is biological CH$\sb4$ consumption in well-drained soils. Although this sink may comprise nearly one-tenth of the annual destruction of atmospheric CH$\sb4$, We know relatively little about it. I conducted a research project to investigate the influences of CH$\sb4$ supply, soil moisture, dissolved salts, and NH$\sb4\sp+$-fertilizer on the activity of soil CH$\sb4$ oxidizers. When starved of CH$\sb4$, two upland taiga soils gradually lost their capacities to oxidize CH$\sb4$, indicating that the process was not merely fortuitous, and that the organisms involved were truly methanotrophic. The relationship between soil moisture and CH$\sb4$ consumption was parabolic, with maximum oxidation occurring at a moisture level that achieved the maximum possible CH$\sb4$ diffusion rate, while minimizing water stress on the methanotrophs. Optimal soil moisture occurred in a relatively narrow range among an array of physically dissimilar soils, providing that moisture content was expressed as a percentage of the water holding capacity fo a particular soil, rather than as absolute water content. In recent years, one of the most intensely investigated controls on soil CH$\sb4$ consumption has been its inhibition by NH$\sb4\sp+$-fertilizer. In addition to NH$\sb4\sp+,$ however, I found that other ions inhibited CH$\sb4$ oxidation. In some soils non-NH$\sb4\sp+$ ions were so toxic that they completely masked the NH$\sb4\sp+$ effect. It is crucial, therefore, to control for salt effects when investigating NH$\sb4\sp+$-inhibition. In both field and laboratory experiments, CH$\sb4$ consumption in a birch soil was sensitive to NH$\sb4\sp+$, whereas a spruce soil was ... Doctoral or Postdoctoral Thesis taiga Alaska University of Alaska: ScholarWorks@UA Fairbanks |
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University of Alaska: ScholarWorks@UA |
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Ecology Microbiology Biogeochemistry |
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Ecology Microbiology Biogeochemistry Gulledge, Jay Michael Soil consumption of atmospheric methane: Importance of microbial physiology and diversity |
topic_facet |
Ecology Microbiology Biogeochemistry |
description |
Dissertation (Ph.D.) University of Alaska Fairbanks, 1996 Recently, atmospheric CH$\sb4$ concentration has risen dramatically, apparently due to human activities. Since is CH$\sb4$ is involved in several atmospheric processes that regulate Earth's climate, it is important that we understand the factors that control its atmospheric concentration. One such factor is biological CH$\sb4$ consumption in well-drained soils. Although this sink may comprise nearly one-tenth of the annual destruction of atmospheric CH$\sb4$, We know relatively little about it. I conducted a research project to investigate the influences of CH$\sb4$ supply, soil moisture, dissolved salts, and NH$\sb4\sp+$-fertilizer on the activity of soil CH$\sb4$ oxidizers. When starved of CH$\sb4$, two upland taiga soils gradually lost their capacities to oxidize CH$\sb4$, indicating that the process was not merely fortuitous, and that the organisms involved were truly methanotrophic. The relationship between soil moisture and CH$\sb4$ consumption was parabolic, with maximum oxidation occurring at a moisture level that achieved the maximum possible CH$\sb4$ diffusion rate, while minimizing water stress on the methanotrophs. Optimal soil moisture occurred in a relatively narrow range among an array of physically dissimilar soils, providing that moisture content was expressed as a percentage of the water holding capacity fo a particular soil, rather than as absolute water content. In recent years, one of the most intensely investigated controls on soil CH$\sb4$ consumption has been its inhibition by NH$\sb4\sp+$-fertilizer. In addition to NH$\sb4\sp+,$ however, I found that other ions inhibited CH$\sb4$ oxidation. In some soils non-NH$\sb4\sp+$ ions were so toxic that they completely masked the NH$\sb4\sp+$ effect. It is crucial, therefore, to control for salt effects when investigating NH$\sb4\sp+$-inhibition. In both field and laboratory experiments, CH$\sb4$ consumption in a birch soil was sensitive to NH$\sb4\sp+$, whereas a spruce soil was ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Gulledge, Jay Michael |
author_facet |
Gulledge, Jay Michael |
author_sort |
Gulledge, Jay Michael |
title |
Soil consumption of atmospheric methane: Importance of microbial physiology and diversity |
title_short |
Soil consumption of atmospheric methane: Importance of microbial physiology and diversity |
title_full |
Soil consumption of atmospheric methane: Importance of microbial physiology and diversity |
title_fullStr |
Soil consumption of atmospheric methane: Importance of microbial physiology and diversity |
title_full_unstemmed |
Soil consumption of atmospheric methane: Importance of microbial physiology and diversity |
title_sort |
soil consumption of atmospheric methane: importance of microbial physiology and diversity |
publishDate |
1996 |
url |
http://hdl.handle.net/11122/9424 |
geographic |
Fairbanks |
geographic_facet |
Fairbanks |
genre |
taiga Alaska |
genre_facet |
taiga Alaska |
op_relation |
http://hdl.handle.net/11122/9424 |
_version_ |
1766214691377381376 |