We use a combination of laboratory and field measurements, and multi-scale modeling to further understanding of how microbial metabolism shapes carbon, nitrogen, and phosphorus biogeochemistry within terrestrial and aquatic ecosystems.
Nitrogen cycling within a mountainous watershed.
Snowmelt dominated mountainous watersheds are characterized by substantial heterogeneity that determine hydrological flow paths and water residence times through distinct catchment subsystems. Despite advances in understanding the spatial and temporal drivers of biogeochemical cycling within snowmelt-dominated ecosystems, knowledge gaps remain. This project is trying establish a budget for nitrogen, which is a major limiting element within the East River (CO) catchment. We’re using a combination of field and lab measurements and modeling to quantify or estimate the input, transformation, and export of different organic and inorganic nitrogen species around the catchment across different seasons.
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Litter decomposition and phosphorus cycling within tropical forests.
This project (with postdoc, Eva Lloret-Sevilla) is part of the biogeochemical component of NGEE-Tropics. Our field work uses litter-bags to examine the plant and microbial traits involved in the decomposition or leaf litter and assimilation of phosphorus (a limiting element in many tropical forests soils).
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Climate change impacts on arctic permafrost.
Funded by DOE’s next generation ecosystem experiment located in Alaska (NGEE-Arctic), we are employing a mechanistic model (ecosys, eg., Grant et al., 2017) to ask how conclusions on carbon and nutrient cycling drawn from short-term perturbation experiments (approximated 10-year open top chamber warming experiments) and long-term, climate change experiments (out to 2100).
Microbial response to drought.
This experiment examines the response of individual isolates and microbial communities from semi-arid and humid, tropical forest soils to reoccurring drought. This is a multi scale experiment, examining the metabolic response to perturbation at the scale of the individual microbe, and simple community, in laboratory soil mesocosms, and by leveraging throughfall exclusion experiments in the field. This study aims to further understanding emergent understanding of how microbial metabolism and community composition feeds back on the formation of soil organic matter and its in situ stability through sorption onto mineral surfaces.
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This work is supported by the DOE Early Career
Award program, and individual grants from the Joint Genome Institute, and the Advanced Light Source at Berkeley National Lab. Dwivedi et al., 2019 |
Microbial trait-based models.
We use conceptual abstractions of soil microbial and algal physiology to better understand community dynamics, community interactions, and feedbacks to biogeochemical rates.
