COS 292-3 - Simulated snowpack drives rhizosphere microbial community structure in a subarctic soil

Abstract: In the Arctic and subarctic, climate change is resulting in reduced snowpack extent and earlier snowmelt. Altered snowpack conditions will likely have significant ecological consequences by affecting both individual organisms—above- and below-ground—and their interactions. The aim of this study was to determine the effect of temperature from altered snowpack conditions on overall microbial community structure and rhizosphere recruitment across representatives of three subarctic plant functional groups. We hypothesized that temperature changes due to the presence or absence of simulated snowpack would influence rhizosphere communities more than plant type. Planted microcosms were established using a tree, forb, grass, or no plant control and subjected to either freeze-thaw cycling or static sub-zero temperatures to simulate the absence or presence of snow, respectively. Our results showed rhizosphere communities exhibited reduced diversity compared to bulk soils and were influenced by snowpack and to a lesser extent plant type. We found that plants have a core microbiome that is persistent under different snowpack scenarios but also temperature-specific rhizosphere microbes. Our findings suggest that reduced snowpack conditions will result in a greater shift between summertime and wintertime microbial communities, which could alter plant-microbe interactions during the growing season.