Applying R-Osmos To Quantify Hot Moments in a High Mountain Watershed: Codevelopment of Novel Methodology to Advance Terrestrial-Aquatic Interface Models
Authors
Andrew Thurber1 (andrew.thurber@oregonstate.edu), Laura Lapham2*, Frederick Colwell1, Dipankar Dwivedi3, Kenneth Hurst Williams3
Institutions
1Oregon State University, Corvallis, OR; 2University of Maryland–Solomons, MD; 3Lawrence Berkeley National Laboratory, Berkeley, CA
Abstract
Watershed function is driven by habitat heterogeneity and microbial activity integrated over space and time. These habitats experience seasonal changes in redox zonation with water flow shifting biogeochemical cycles and perturbing the microbial communities that mediate biogeochemical processes. Features such as river meanders can create hot spots of biological activity, however they must be directly sampled to be understood. This project will quantify the impact of hot spots and moments on microbial rates, focusing on two critical processes: methane (CH4) oxidation and nitrate (NO3) reduction, at the DOE’s East River Watershed Function Science Focus Area. For this project, researchers developed novel, continuous, time-integrating, in situ microbial rate samplers to inform the magnitude and variation in biogeochemical processes across the terrestrial-aquatic interface. In 2023, the team deployed these uniquely configured osmotic samplers (OsmoSamplers) to continuously quantify the rate at which microbial communities transform methane and nitrate on either side of a river meander. One of the packages was impacted by water level variation and was retrieved after a few months, however the second package (the downstream one), remains in place collecting data about the impact of meanders of river biogeochemistry. The remaining sampler package will be retrieved in early summer, which, after laboratory-based analysis, will allow the team to incorporate spatially explicit rate measurements of NO3 and CH4 oxidation and assimilation into reactive transport models developed for the region. Here, the team will cover the overall aims of the project, update progress to date, and highlight opportunities that this research framework may provide for collaboration with other Science Focus Area users.