Exploring the Microbial World of the Arctic benthos

Microbial community composition can provide insights into both ecological and physical dynamics of a given habitat or ecosystem. For instance, the taxonomic community composition of bacteria may reflect local biogeochemical processes, movement of varying water masses, nutrient availability at depth, and fluctuations in benthic food web dynamics. By connecting taxonomic composition to the known metabolic strategies employed by certain bacterial taxa, we can identify key biogeochemical processes in a given study area. The Beaufort Sea is an Arctic marginal sea characterized by strong biological and physical gradients and is subject to ecosystem shifts resulting from increasing atmospheric and sea surface temperatures, reduction of sea ice extent and thickness, and increased runoff from coastal permafrost. Therefore it provides a unique and ideal study area for exploring bacterial communities in sediments. In order to better understand microbial processes in Beaufort Sea sediments, 16S amplicon and metagenomic surveys were used to characterize bacterial communities from the upper 1cm layer of sediments from 15 sites across varying water depths. Bacterial community composition and diversity were also examined with respect to local biotic and abiotic variables including temperature, salinity, depth, latitude, longitude, chlorophyll-a, grain size, and stable isotope data. We will discuss bacterial alpha and beta diversity, the metabolic strategies reflected in the taxonomic community composition, and the functional diversity of these communities with respect to environmental parameters.