2024 Abstracts

Opportunities for Rhizosphere Function, Biogeochemistry and Terrestrial-Atmospheric User Research at the Environmental Molecular Sciences Laboratory


John Bargar* (john.bargar@pnnl.gov), Amir Ahkami, Swarup China, Emily Graham, Douglas Mans


Environmental Molecular Sciences Laboratory, Richland, WA



The Environmental Transformations and Interactions Science Area at the Environmental Molecular Sciences Laboratory (EMSL) provides best-in-class instrumentation and expertise for external users to investigate cycling, transformation, and transport of critical nutrients, elements, and particles at molecular and microstructural scales. Improved knowledge of these areas is critical to improving Earth systems and climate models. Researchers are focused on systems-scale research in the following three areas:

Rhizosphere Function investigates the impact of root system architecture and rhizodeposition on the molecular and structural mechanisms root-soil- microbe interactions. The goal is to improve prediction of root-controlled processes and their impacts on plant resilience, nutrient cycling, and volatile emissions under environmental changes. Key capabilities include phytotrons, carbon (C) flux measurement using isotope ratio mass spectrometry (IRMS) and nanoscale secondary ion mass spectrometry (NanoSIMS), micromodels, multiomics, metabolite imaging, and nondestructive root system imaging.

Terrestrial-Atmosphere Processes investigates emission mechanisms of aerosols and gases from plants and soil into the atmosphere and the subsequent formation of particles, with a focus on multiphase aerosol interfacial chemistry and aging processes near Earth’s surface and extending up to the atmospheric boundary layer. Research also focuses on how aerosols participate in warm and cold cloud formation by acting as cloud condensation nuclei or ice nucleating particles and how these impact Earth’s radiative budget and aerosol deposition on terrestrial ecosystems.

Biogeochemical Transformations investigates the interplay of geology, chemistry, and biology to understand molecular/microscale mechanisms of biogeochemical transformations of C, nutrients, and minerals. User research directly supports improvement of biogeochemical process representations, process scaling from molecular-to-landscape, and predictive Earth system models. Key capabilities include X-ray computed tomography, helium ion and scanning electron microscopy, mass spectrometry compound identification and imaging, and Mössbauer, X-ray photoelectron, and nuclear magnetic resonance spectroscopy.

EMSL is a DOE Office of Science user facility.