The Science

This project advances modeling capabilities to assess the functioning of a hyporheic zone under various climatic conditions, impacted by surface water–groundwater interactions, and feedbacks with microbial biomass.

The Impact

Project results show that while highly losing rivers have greater hyporheic carbon dioxide (CO₂) and nitrogen (N₂) production, gaining rivers allowed the greatest fraction of CO₂ and N₂ production to return to the river.

Summary

River systems are important components of the landscape that help to degrade contaminants, support food webs, and transform organic matter. In this study, the research team developed and tested a model that could help reveal the role of the riverbed for these ecosystem services. the researchers used the model to explore how different riverbed conditions eventually control the fate of carbon and nitrogen. Project results show that carbon and nitrogen transformations and the potential suite of microbial behaviors are dependent on the riverbed sediment structure and the water table conditions in the local groundwater system. The implications of this are that the riverbed sediments and the cumulative effect of water table conditions can control hyporheic processing. Under future river discharge conditions, assuming reduced river flows and siltation of riverbeds, reductions in total hyporheic processing may be observed.

Principal Investigator

Michelle Newcomer
Lawrence Berkeley National Laboratory
mnewcomer@lbl.gov

Program Manager

Paul Bayer
U.S. Department of Energy, Biological and Environmental Research (SC-33)
Environmental System Science
paul.bayer@science.doe.gov

Funding

This research was supported by the Sonoma County Water Agency (SCWA), the Office of Biological and Environmental Research, within U.S. Department of Energy Office of Science, under award DE-AC02-05CH11231, as well as the associated Student Research Fellowship Program, and the UFZ-Helmholtz Centre for Environmental Research, Leipzig, Germany.

References