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A model describing the interactions between anaerobic microbiology and geochemistry in a soil amended with glucose and nitrate
Author(s) -
Dassonville F.,
Renault P.,
Vallès V.
Publication year - 2004
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1046/j.1365-2389.2004.00594.x
Subject(s) - chemistry , acetogenesis , denitrification , environmental chemistry , fermentation , nitrate , decomposition , methanogenesis , cambisol , anaerobic exercise , sulfate , soil water , food science , ecology , organic chemistry , nitrogen , biology , methane , physiology
Summary Under anaerobic conditions, microbes closely interact with geochemical reactions and can have an impact on the soil, the deep vadose zone, the underlying aquifer and the atmosphere. We have designed a model combining anaerobic microbial activities with geochemical reactions in the soil, and assessed it in batch experiments. The model describes the dynamics of six functional microbial communities, their decomposition after death, and the catabolism of carbohydrates through denitrification, dissimilatory NH 4 + production, Fe(III) reduction, fermentation, acetogenesis, and SO 4 2– reduction. It was combined with a model that thermodynamically describes acid–base, reduction–oxidation and complexation reactions in solution, and kinetic precipitation and dissolution. Batch incubations were done on a Calcic Cambisol, either without amendment, or after supplying (i) glucose or (ii) glucose and NO 3 – . Gases, mineral cations and anions, glucose, fatty acids and alcohols were measured during incubation. Net production of CO 2 was similar for both glucose treatments, about 40 times larger than in the control. For the glucose treatments, the main microbial activities were fermentation, acetogenic transformation of ethanol, and oxidation of H 2 . When the soil was enriched with NO 3 – , no H 2 was produced, and microbial activities were rapidly inhibited by NO 2 – . The model shows these trends as well as geochemical characteristics including pH and reduction–oxidation potential.