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Dr. Tanya Soule
Department of Biology
Department of Biology
Biological soil crusts (BSCs) are microbial assemblages that play important roles in the areas they inhabit, and can influence aspects such as local nitrogen flux, water infiltration, and plant seedling germination. In the dune environment, BSCs can form close connections with sand particles to stabilize dunes at their surface. Despite their potential critical role within Indiana Dunes State Park, little is known about their diversity, ecology, or interactions with plant communities there. The objective of this study, therefore, was to examine abiotic and biotic factors that influence dune BSCs, using Illumina high-throughput sequencing (HTS) to characterize these microbial communities. We hypothesized that specific environmental variables would influence BSC microbial diversity. In this study we sampled every 50m along a 550m transect, moving from the Lake Michigan shore inward to the hind-dune environment. At each sampling point soil pH, PAR, UV, and chlorophyll and scytonemin pigments were measured, and plant community cover, richness, and diversity were assessed. Moisture, conductivity, and nutrient content (total N and P) were also measured at every 100m. Overall, our HTS effort recovered 1,214,542 bacterial sequences across our 30 samples, and five major phyla were found to dominate our BSC samples, these being Proteobacteria (~20% of all sequences), Acidobacteria (~17%), Actinobacteria (~16%), Bacteriodetes (~17%), and Cyanobacteria (~10%). While there were no significant trends observed for BSC diversity moving along the transect, we did note a significant negative correlation for biological pigments and soil pH, suggesting a shift in the microbial community structure in response to these environmental parameters. The tendency for pH to structure terrestrial microbial communities has been noted in many studies; therefore, we are currently carrying out additional analyses to examine BSC community composition changes across our transect in relation to measured abiotic variables, with pH being of special interest.
Smith-Graber, Taylor, "Microbial Diversity of Biological Soil Crusts of the Indiana Dunes State Park" (2017). 2017 IPFW Student Research and Creative Endeavor Symposium. 6.