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

Abstract

Functional diversities of micro-organisms in arctic soils at three incubation temperatures were assessed using sole-carbon-source-utilization (SCSU). Soil samples were collected from an area of anthropogenic fertilization (mixed Dorset/Thule/Historic site), an area of animal enrichment (bird rock perches), and unaltered tundra (raised beach; control soil site). The micro-organisms were extracted from the soil samples and inoculated into Gram-negative (GN) Biolog plates incubated at 30°C, 10°C, and 4°C. Calculations of the Shannon index, substrate utilization richness, Shannon evenness, and the Jaccard coefficient of similarity were based upon substrate utilization on the Biolog plates. Principal component analysis distinguished microbial communities in enriched soils from unenriched soils. At 10°C and 4°C, Shannon indices of enriched soil microbial communities (10°C: soils influenced by wild animals=4.28, soils influenced by human activities=4.20; 4°C: soils influenced by wild animals=4.15, soils influenced by human activities=4.03) were significantly higher than unenriched soil microbial communities (10°C: 3.66; 4°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°C and 10°C) yielded greater resolution between soil microbial communities than 30°C based on Biolog colour development patterns.