Analysis of soil bacterial community structures in Wyoming grassland ecosystems

Spatial and temporal analyses of soil bacterial community structures were conducted to determine what scale controls on soil bacterial diversity operate. For field and plot scale analyses, an ecosystem having either continuous, homogeneous grass cover or patchy heterogeneous plant cover were examined. Bacterial communities under homogeneous grass cover were spatial similar for distances up to 100 meters and temporally consistent over 180 days. In contrast, bacterial community strictures in the heterogeneous plant cover ecosystem exhibited pronounced spatial variability. Although shrub cover was shogun to significantly influence diversity patterns, most variability could not be accounted for by spatial characteristics at scales measured (4.5 to 60 cm).; At smaller scales, soil structure would be expected to influence bacterial community structure, although methods to determine these relationships are limited. A fractionation procedure, allowing for analysis of inner-microaggregate microbial populations was developed. Distinct spatial stratification of division-level bacterial lineages was apparent in microaggregates of soils reclaimed after surface coal mining and in undisturbed soils. While Proteobacteria representation was found to be high for whole-microaggregates, inner-microaggregates of both undisturbed and reclaimed soils were dominated by Actinobacteria . The high abundance of potentially filamentous, antibiotic producing Actinobacteria within inner-aggregate environments may have important implications for soil structure formation and ecological process regulation.; Spatial characteristics and fatty acid metllyl ester (FAME) based soil microbial community structure and selected soil chemical factors were analyzed in soil surrounding predominant plant species in sites reclaimed after surface mining and adjacent, undisturbed sites. Unlike undisturbed soils, reclaimed soils exhibited localized enrichment of bacterial, fungal, and total microbial biomass. Strong spatial stratification of undisturbed soil organic matter and ammonium pools was found. These results suggest very different controls on ecological processes occurred in the two systems.; To test the utility of FAME biomarkers as indicators of reclamation progress, FAME bacterial, fungal, and total biomass biomarkers extracted from reclaimed surface mine soils of different ages and an adjacent undisturbed site were compared with other indicators of reclamation progress and ecosystem stability. Our results indicate that the ratio of bacterial to fungal biomass may be a useful indicator of restoration progress.