Title of article :
Microbial dynamics in an anaerobic soil slurry amended with glucose, and their dependence on geochemical processes
Author/Authors :
Dassonville، نويسنده , , F. and Godon، نويسنده , , J.J. and Renault، نويسنده , , P. and Richaume، نويسنده , , A. and Cambier، نويسنده , , P.، نويسنده ,
Issue Information :
ماهنامه با شماره پیاپی سال 2004
Pages :
14
From page :
1417
To page :
1430
Abstract :
Under anoxic conditions, microbial activities interact closely with geochemical reactions and consequently affect soils, underlying aquifers, and the atmosphere. Recent studies have noted the relationships between microbial biodiversity and environmental conditions, but the dynamics of numerous coexisting microbial groups in connection with soil biogeochemical processes has never been investigated. In this work, we investigated the dynamics of anaerobic microbial populations using a new method combining PCR-SSCP and epifluorescent direct counts, and analysed these results in the light of biogeochemical changes. Batch incubations were performed over an 8-day period on a calcic cambisol (WRB) incubated anaerobically, either without amendment (treatment C) or after adding glucose (treatment +G). In treatment +G, the predominant microbial processes included (i) NO3− and NO2− reduction during the first 12 and 24 h of incubation respectively, (ii) fermentations during the first 6 days with non-symbiotic N2 fixation between days 1 and 6, enabling bacterial growth during this period, and probably (iii) reduction of FeIII by H2 oxidation throughout the incubation period. In treatment C, microbiological and geochemical measurements revealed no prominent microbial activities, and the PCR-SSCP method led to complex bacterial density profiles without prominent peaks. In treatment +G, 78 microbial groups were distinguished; these were divided into seven sets (A to G) according to their dynamics. Bacteria belonging to sets A, E and F grew during the period of intense fermentation and were probably able to fix N2, as is the case with Clostridium butyricum (set A). Bacteria belonging to sets B, D, and G were probably able to reduce FeIII to FeII with concomitant oxidation of H2 into H3O+, but unable to fix N2. Two microbial groups in these sets were closely related to Clostridium favosporum (set B) and the genus Bacillus (set B). Bacteria belonging to class C were probably only able to reduce N oxide(s). Lastly, we obtained two similar estimates of the gross increase in microbial biomass by taking into account either (i) the sum of gross increases for the 78 microbial groups, or (ii) the energy yield of catabolic reactions minus the energy requirement for N2 fixation.
Keywords :
Microbial dynamics , soil , Anaerobic microbiology , geochemistry , Fermentation
Journal title :
Soil Biology and Biochemistry
Serial Year :
2004
Journal title :
Soil Biology and Biochemistry
Record number :
2182158
Link To Document :
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