A5011203458- Climate change and permafrost
- Peatlands and Wetlands Ecology
- Microbial Community Ecology and Physiology
- Soil Carbon and Nitrogen Dynamics
- Cryospheric studies and observations
- Methane Hydrates and Related Phenomena
- Geology and Paleoclimatology Research
- Polar Research and Ecology
- Indigenous Studies and Ecology
- Atmospheric and Environmental Gas Dynamics
- Coastal wetland ecosystem dynamics
- Mycorrhizal Fungi and Plant Interactions
- Gut microbiota and health
- Bacteriophages and microbial interactions
- Fire effects on ecosystems
- Soil and Water Nutrient Dynamics
- Geological Studies and Exploration
- Forest Ecology and Biodiversity Studies
- Genomics and Phylogenetic Studies
- Plant and Fungal Interactions Research
- Enzyme-mediated dye degradation
- Plant Ecology and Soil Science
- Landslides and related hazards
- Isotope Analysis in Ecology
- Botany and Plant Ecology Studies
United States Geological Survey
2016-2025
Geology, Minerals, Energy, and Geophysics Science Center
2020-2024
Pacific Science Center
2015-2022
Pacific Island Ecosystems Research Center
2009-2021
Government of the United States of America
2021
Menlo School
2012-2019
California Water Science Center
2015-2019
University of Alaska Fairbanks
2019
Oak Ridge National Laboratory
2013
University of Michigan
2004-2007
Abstract [1] This synthesis addresses the vulnerability of North American high-latitude soil organic carbon (SOC) pool to climate change. Disturbances caused by warming in arctic, subarctic, and boreal environments can result significant redistribution C among major reservoirs with potential global impacts. We divide current northern SOC pools into (1) near-surface soils where is affected seasonal freeze-thaw processes changes moisture status, (2) deeper permafrost peatland strata down...
Nitrification and denitrification processes are crucial to plant nutrient availability, eutrophication greenhouse gas production both locally globally. Unravelling the major environmental predictors for nitrification is thus pivotal in order understand model nitrogen (N) cycling. Here, we sampled five community types characteristic of interior Alaska, including black spruce, bog birch, tussock grass two fens. We assessed abundance functional genes affiliated with (bacterial archaeal amoA)...
Atmospheric nitrogen (N) deposition derived from fossil‐fuel combustion, land clearing, and biomass burning is occurring over large geographical regions on nearly every continent. Greater ecosystem N availability can result in greater aboveground carbon (C) sequestration, but little understood as to how soil C storage could be altered by deposition. High concentrations of inorganic accelerate the degradation easily decomposable litter slow decomposition recalcitrant containing amounts...
Abstract Despite decades of research, the ecological determinants microbial diversity remain poorly understood. Here, we test two alternative hypotheses concerning factors regulating fungal in soil. The first states that higher levels plant detritus production increase supply limiting resources (i.e. organic substrates) thereby increasing diversity. Alternatively, greater increases range substrates entering soil, number niches to be filled by a array heterotrophic fungi. These were...
Approximately 1700 Pg of soil carbon (C) are stored in the northern circumpolar permafrost zone, more than twice as much C atmosphere. The overall amount, rate, and form released to atmosphere a warmer world will influence strength feedback climate change. We used survey quantify variability perception vulnerability Experts were asked provide quantitative estimates change response four scenarios warming. For highest warming scenario (RCP 8.5), experts hypothesized that release from zone...
High-throughput RNA sequencing offers broad opportunities to explore the Earth virome. Mining 5,150 diverse metatranscriptomes uncovered >2.5 million virus contigs. Analysis of >330,000 RNA-dependent polymerases (RdRPs) shows that this expansion corresponds a 5-fold increase known diversity. Gene content analysis revealed multiple protein domains previously not found in viruses and implicated virus-host interactions. Extended RdRP phylogeny supports monophyly five established phyla reveals...
In permafrost (perennially frozen ground) microbes survive oligotrophic conditions, sub-zero temperatures, low water availability and high salinity over millennia. Viable life exists in tens of thousands years old but we know little about the metabolic physiological adaptations to challenges presented by ground geologic time. this study asked whether increasing age associated stressors drive adaptive changes community composition function. We conducted deep metagenomic 16 S rRNA gene...
Permafrost degradation in peatlands is altering vegetation and soil properties impacting net carbon storage. We studied four adjacent sites Alaska with varied permafrost regimes, including a black spruce forest on peat plateau permafrost, two collapse scar bogs of different ages formed following thermokarst, rich fen without permafrost. Measurements included year-round eddy covariance estimates dioxide (CO