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Record 13 of 4973
Comparative ecology of H2 cycling in sedimentary and phototrophic ecosystems
External Online Source: doi:10.1023/A:1020517924466
Author and Affiliation:
Hoehler, Tori M.(NASA Ames Research Center, Moffett Field CA United States)
Albert, Daniel B.
Alperin, Marc J.
Bebout, Brad M.
Martens, Christopher S.
Des Marais, David J.
Abstract: The simple biochemistry of H2 is critical to a large number of microbial processes, affecting the interaction of organisms with each other and with the environment. The sensitivity of each of these processes to H2 can be described collectively, through the quantitative language of thermodynamics. A necessary prerequisite is to understand the factors that, in turn, control H2 partial pressures. These factors are assessed for two distinctly different ecosystems. In anoxic sediments from Cape Lookout Bight (North Carolina, USA), H2 partial pressures are strictly maintained at low, steady-state levels by H2-consuming organisms, in a fashion that can be quantitatively predicted by simple thermodynamic calculations. In phototrophic microbial mats from Baja California (Mexico), H2 partial pressures are controlled by the activity of light-sensitive H2-producing organisms, and consequently fluctuate over orders of magnitude on a daily basis. The differences in H2 cycling can subsequently impact any of the H2-sensitive microbial processes in these systems. In one example, methanogenesis in Cape Lookout Bight sediments is completely suppressed through the efficient consumption of H2 by sulfate-reducing bacteria; in contrast, elevated levels of H2 prevail in the producer-controlled phototrophic system, and methanogenesis occurs readily in the presence of 40 mM sulfate.
Publication Date: Aug 01, 2002
Document ID:
20040087973
(Acquired Sep 07, 2004)
Subject Category: LIFE SCIENCES (GENERAL)
Document Type: Journal Article
Publication Information: Antonie van Leeuwenhoek (ISSN 0003-6072); Volume 81; 1-4; 575-85
Publisher Information: Netherlands
Description: In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: BACTERIA; CYCLES; ECOLOGY; ECOSYSTEMS; HYDROGEN; SEA WATER; SEDIMENTS; METHANE
Other Descriptors: BACTERIA/GROWTH & DEVELOPMENT/METABOLISM; ECOSYSTEM; GEOLOGIC SEDIMENTS/MICROBIOLOGY; HYDROGEN/METABOLISM; SEAWATER/MICROBIOLOGY; SULFUR-REDUCING BACTERIA/GROWTH & DEVELOPMENT/METABOLISM; COMPARATIVE STUDY; ECOLOGY; METHANE/METABOLISM; SUPPORT, NON-U.S. GOV'T; SUPPORT, U.S. GOV'T, NON-P.H.S; REVIEW; REVIEW, TUTORIAL
Availability Source: Other Sources
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