**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** GLOBALLY, FORESTS PROVIDE ECOSYSTEM SERVICES VALUED AT ~$5 TRILLION ANNUALLY. SUCH SERVICES INCLUDE CARBON STORAGE, THE PROCESSING OF NUTRIENTS, AND THE REGULATION OF DOWNSTREAM WATER QUANTITY AND QUALITY. WILDFIRE IS A NATURAL COMPONENT OF HEALTHY FORESTS, BUT THE INTENSITY AND FREQUENCY OF FIRE DISTURBANCE HAS DRAMATICALLY INCREASED IN RECENT DECADES. ALTHOUGH THESE LARGE DISTURBANCES LIKELY IMPACT THE SOIL MICROBIOME AND ASSOCIATED BIOGEOCHEMICAL PROCESSES, WE LACK CRITICAL INFORMATION ON HOW WILDFIRE ALTERS MICROBIOME FUNCTION AND ASSOCIATED CARBON AND NITROGEN CYCLING.ADDRESSING A KEY PROGRAM AREA PRIORITY OF CHARACTERIZING MICROBIOMES THAT OPTIMIZE ENVIRONMENTAL PROCESSES, WE PROPOSE TO DEVELOP A MECHANISTIC UNDERSTANDING OF THE FUNCTIONAL SHIFTS WITHIN THE MICROBIAL COMMUNITY IN BURNED SOILS AND THE CORRESPONDING MOLECULAR LEVEL CHANGES IN MICROBIALLY-AVAILABLE CARBON AND NITROGEN. SHORT-TERM RESPONSES WILL BE MEASURED ACROSS BURN SEVERITY GRADIENTS AT TWO RECENTLY BURNED FORESTED CATCHMENTS IN COLORADO. FROM HERE, WE WILL LEVERAGE OUR UNIQUE ACCESS TO CONTROLLED PILE-BURNS WITHIN COLORADO FORESTS THAT PROVIDE A 60-YEAR BURN AND ECOSYSTEM RECOVERY CHRONO-SEQUENCE, ENABLING US TO ASSESS LONGER-TERM MICROBIOLOGICAL AND GEOCHEMICAL RESPONSES IN AN ESTABLISHED POST-FIRE FIELD-SCALE LABORATORY. FINALLY, WE WILL USE LABORATORY PYROCOSMS TO IDENTIFY MICROBIAL AND BIOGEOCHEMICAL CHANGES UNDER A CONTROLLED RANGE OF FIRE CONDITIONS, YIELDING COMPLEMENTARY, YET TRACTABLE, DATASETS TO SUPPORT FIELD OBSERVATIONS. ACROSS THESE SCALES WE WILL USE A MULTI-OMIC FRAMEWORK THAT INFORMS ON COMMUNITY FUNCTIONAL POTENTIAL AND ACTIVITY AND GENERATES DATA TO PARAMETERIZE METABOLIC MODELS THAT LINK CHEMICAL AND MICROBIAL DATA. TOGETHER, THESE INSIGHTS WILL SHED NEW LIGHT ON MICROBIAL CONTROLS ON SOIL HEALTH FOLLOWING WILDFIRE AND WILL AID DEVELOPMENT OF MORE ACCURATE BIOGEOCHEMICAL MODELS OF POST-FIRE WATERSHED RESPONSES.