Overview of Rhizosphere Function and Terrestrial–Atmospheric Processes Research at the Environmental Molecular Sciences Laboratory


John Bargar* (John.Bargar@pnnl.gov), Amir Ahkami, Swarup China, Justin Teeguarden, Douglas Mans


Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA



In 2023, EMSL launched two new Integrated Research Platforms (IRPs) to focus resources for molecular and microscale user research in critical ESS research domains:

  • Rhizosphere Function (RF) IRP: This program addresses the impacts of root system architecture and root exudates on highly interlinked rhizosphere components (e.g., microbial communities, organic matter, and soil mineralogy) in response to environmental perturbations. Supported research aims to dissect interactions between roots, the soil, and microbes to understand the impacts and mechanisms of root-controlled processes on plant resilience and biogeochemical cycling of carbon, nutrients, and mineral elements. Key capabilities include phytotrons, carbon flux using stable isotope probes and isotope-ratio mass spectrometry, synthetic soil habitats, quantitative cell imaging, molecular and chemical processes, and nondestructive measurement and imaging of root system architecture.
  • Terrestrial-Atmosphere Processes (TAP) IRP: This program addresses emission mechanisms of aerosols and gases from plants and soils into the atmosphere. It also addresses molecular processes that control the multiphase interfacial chemistry and aging processes occurring near Earth’s surface and extending up to the atmospheric boundary layer. User research 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.

Funding Information

EMSL is a DOE Office of Science user facility sponsored by DOE-BER. The EMSL user science program supports fundamental biological and environmental research across the BER research domain, from bedrock to living organisms to the troposphere. Activities in the RF and TAP IRPs, and across the EMSL user program, are generating critical observational data and model-based data to support Earth systems and climate models.