The LANL Genomic Science SFA is focused on microbial communities in surface soil horizons and their functional processes that influence soil carbon storage and release. The goal of the SFA is develop understanding of the microbial and ecosystem factors that control carbon partitioning in soils at the ecosystem, microbial community, cellular and molecular levels. The SFA will address this goal by examining soil carbon cycling under conditions of environmental change and understanding the metabolic and ecological roles of fungi and bacteria in surface soils in two important temperate ecosystems - forests and arid grass/shrub lands. Advancing fundamental knowledge of soil communities within the context of altered environmental regimens will improve our ability to predict and possibly manage ecosystem contributions to global climate. This involves discovery of fundamental principles at different scales that influence the organization, interactions, and response of soil communities.