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Thermodynamics and the role of hydro...

Hoehler, Tori Michael.

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Thermodynamics and the role of hydrogen in anoxic sediments.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Thermodynamics and the role of hydrogen in anoxic sediments./
Author:	Hoehler, Tori Michael.
Description:	193 p.
Notes:	Source: Dissertation Abstracts International, Volume: 59-07, Section: B, page: 3297.
Contained By:	Dissertation Abstracts International59-07B.
Subject:	Biogeochemistry. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9840926
ISBN:	0591948672

Thermodynamics and the role of hydrogen in anoxic sediments.
Hoehler, Tori Michael.

Thermodynamics and the role of hydrogen in anoxic sediments. - 193 p.

Source: Dissertation Abstracts International, Volume: 59-07, Section: B, page: 3297.

Thesis (Ph.D.)--The University of North Carolina at Chapel Hill, 1998.

The redox chemistry of the oceans and atmosphere is driven in large part by the biogeochemical cycling that occurs in anoxic environments. This cycling is mediated by communities of anaerobic bacteria that utilize molecular hydrogen as the primary carrier of electrons. Using a framework of thermodynamics, this volume examines the bacterial processes that control and are controlled by H

ISBN: 0591948672Subjects--Topical Terms:

545717
Biogeochemistry.

Thermodynamics and the role of hydrogen in anoxic sediments.
LDR:03191nmm 2200313 4500 001 1815214
005 20060623071159.5
008 130610s1998 eng d
020 $a 0591948672
035 $a (UnM)AAI9840926
035 $a AAI9840926
040 $a UnM $c UnM
100 1 $a Hoehler, Tori Michael. $3 1904650
245 1 0 $a Thermodynamics and the role of hydrogen in anoxic sediments.
300 $a 193 p.
500 $a Source: Dissertation Abstracts International, Volume: 59-07, Section: B, page: 3297.
500 $a Adviser: Marc J. Alperin.
502 $a Thesis (Ph.D.)--The University of North Carolina at Chapel Hill, 1998.
520 $a The redox chemistry of the oceans and atmosphere is driven in large part by the biogeochemical cycling that occurs in anoxic environments. This cycling is mediated by communities of anaerobic bacteria that utilize molecular hydrogen as the primary carrier of electrons. Using a framework of thermodynamics, this volume examines the bacterial processes that control and are controlled by H $\ sb2 $ concentrations in anoxic sediments from the White Oak River and Cape Lookout Bight, North Carolina.
520 $a In a series of laboratory experiments, temperature, terminal electron acceptor, sulfate concentration, and pH were found to exhibit thermodynamic control over steady-state porewater H $\ sb2 $ concentrations. Changes in these parameters alter the free energy yield of bacterially-mediated H $\ sb2 $- consuming reactions; the response of H $\ sb2 $ concentrations in each case tended to offset whatever energetic change had been induced. In the case of temperature and sulfate concentration, the change in H $\ sb2 $ concentrations was exactly sufficient to maintain a constant energy yield ( $\ Delta $\ sb2 $- consuming reaction. In field studies, the observed down-core, seasonal, and inter-environmental variations in H $\ sb2 $ concentrations compare favorably with the laboratory-determined dependencies for the four controls. This thermodynamic control likely results from a competition-induced necessity for terminal bacteria to maintain H $\ sb2 $ concentrations at a minimum level set by bioenergetic considerations.
520 $a The ability of H $\ sb2 $ concentrations to exert thermodynamic control on bacterially-mediated processes was examined in two cases. First, a series of field and laboratory experiments suggest that anaerobic methane oxidation in Cape Lookout Bight sediments represents a reversal of methanogenic CO $\ sb2 $ reduction. It is shown that variations in H $\ sb2 $ concentrations provide a thermodynamic basis for this reversal. Second, the dynamics of acetate-H $\ sb2 $/ CO $\ sb2 $ interconversion were examined. Tracer studies indicate the directionality of this process is controlled by H $\ sb2 $ concentrations. In one instance, acetogenesis from H $\ sb2 $\ sb2 $ was the major H $\ sb2 $- consuming process and consequently the primary control on H $\ sb2 $ concentrations.
590 $a School code: 0153.
650 4 $a Biogeochemistry. $3 545717
650 4 $a Biology, Oceanography. $3 783691
650 4 $a Environmental Sciences. $3 676987
690 $a 0425
690 $a 0416
690 $a 0768
710 2 0 $a The University of North Carolina at Chapel Hill. $3 1017449
773 0 $t Dissertation Abstracts International $g 59-07B.
790 1 0 $a Alperin, Marc J., $e advisor
790 $a 0153
791 $a Ph.D.
792 $a 1998
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9840926