Functional diversity and community structure of micro-organisms in three arctic soils as determined by sole-carbon-source-utilization

Functional diversities of micro-organisms in arctic soils at three incubati on temperatures were assessed using sole-carbon-source-utilization (SCSU). Soil samples were collected from an area of anthropogenic fertilization (mi xed Dorset/Thule/Historic site), an area of animal enrichment (bird rock pe rches), and unaltered tundra (raised beach; control soil site). The micro-o rganisms were extracted from the soil samples and inoculated into Gram-nega tive (GN) Biolog plates incubated at 30 degrees C, 10 degrees C, and 4 degr ees C. Calculations of the Shannon index, substrate utilization richness, S hannon evenness, and the Jaccard coefficient of similarity were based upon substrate utilization on the Biolog plates. Principal component analysis di stinguished microbial communities in enriched soils from unenriched soils. At 10 degrees C and 4 degrees C, Shannon indices of enriched soil microbial communities (10 degrees C: soils influenced by wild animals = 4.28, soils influenced by human activities = 4.20; 4 degrees C: soils influenced by wil d animals = 4.15, soils influenced by human activities=4.03) were significa ntly higher than unenriched soil microbial communities (10 degrees C: 3.66; 4 degrees C: 3.38). Substrate utilization richness and evenness displayed similar trends. Although Jaccard coefficients showed uniformity across the different soil samples, cluster analysis supported patterns demonstrated by PCA. Lower temperatures (4 degrees C and 10 degrees C) yielded greater res olution between soil microbial communities than 30 degrees C based on Biolo g colour development patterns.