Soil microbial community physiology is altered by snow depth

Land in temperate ecosystems, such as sagebrush steppe in Wyoming, is covered by snow during winter. Soil biogeochemical processes that lead to emissions of greenhouse gases are partly dependent on the depth and duration of snow cover. Hence, we conducted an experiment evaluating the role of snow depth on soil microbial emissions of carbon dioxide. We used highway snow fences located at three sites in sagebrush steppe in Southeast Wyoming to create areas of deeper and shallower snow within the same ecosystem. We collected soils in winter, spring and summer from 4 distances from the snowfences (5, 10, 20, 40 m) corresponding to different levels of snow depth and brought them to the laboratory to measure community level physiological profile (CLPP) by using MicrorespTM analysis, which indicates the respiration rate soil microbes utilizing different substrates. We observed that in winter and spring, the soils experiencing deeper snow depth had different CLPP than the soil experiencing shallower snow depth. However, the effect of snow depth experienced during winter and spring was not seen clearly in summer soils. Our results indicate that the physiological activity of soil microbial communities changes with season and responds strongly to the amount of snow cover in winter and spring.