SS2.06 Microbial Diversity in Time and Space
Date: Tuesday, June 11, 2002
Location: Poster Session - VCC
 
ChauhanA, University of Florida, Gainesville, FL, USA, ashvini@ufl.edu
Seo, M, , University of Florida, Gainesville, USA, 
Castro, H, , University of Florida, Gainesville, FL, USA, hfc@mail.ifas.ufl.edu
Krishnakumar, A, , University of Florida, Gainesville, FL, USA, 
Prenger, J, , University of Florida, Gainesville, FL, USA, jprenger@ufl.edu
Ogram, A, V, University of Florida, Gainesville, FL, USA, avo@mail.ifas.ufl.edu
Reddy, K, R, University of Florida, Gainesville, USA, krr@mail.ifas.ufl.edu
 
COMPOSITION AND FUNCTION OF SYNTROPHIC ASSOCIATIONS IN SOILS FROM A NUTRIENT IMPACTED FRESH WATER MARSH
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Nutrient impacts on carbon cycling in soils from the Blue Cypress Marsh, a large freshwater system in Central Florida, were studied. Several lines of evidence suggest differences between the composition and function of syntrophic assemblages in impacted and relatively pristine regions of the marsh. Endogenous and butyrate/propionate induced methanogenesis rates were higher in microcosms with soil from impacted relative to non-impacted regions, and butyrate/propionate induced rates were higher than propionate induced methanogenesis in impacted relative to non-impacted regions. RFLPs of 16S rRNA genes indicate similar methanogenic assemblages in impacted microcosms that differ from RFLP groups from non-impacted regions. This is supported by 16S rDNA sequence analysis indicating hydrogenotrophic methanogens in the impacted regions and not detectable in non-impacted regions of the marsh. Differences between gene sequences characteristic of sulfate reducing bacteria were also evident between impacted and non-impacted regions. Our results suggest that relatively more methane is produced via syntrophic assemblages driven by metabolism of butyrate than by propionate in impacted compared with non-impacted regions of the marsh, and that the composition of these assemblages reflect this difference.