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Linking Nutrient Reactivity and Transport in Subsurface Flowpaths Along a Terrestrial-Estuarine Continuum

Active Dates 9/1/2020-8/31/2024
Program Area Environmental Systems Science
Project Description
Salt marshes are critical “hot spots” of nutrient processing and retention and thus play an important role in improving coastal water quality. In particular, coastal salt marshes retain upwards of one-third of terrestrially derived nitrogen (N) loads, helping to mitigate negative environmental impacts such as eutrophication and harmful algal blooms. This removal is largely driven by sediment microbial activity, which is controlled by spatial and temporal variability in the availability in oxygen and organic matter. These changes in redox characteristics and substrate availability impact the pathways by which N is processed by microbes. Our study objective is to address a substantial knowledge gap in our understanding of the hydrologic and environmental factors that drive solute fate and transport at the subsurface terrestrial-marine boundary at tidal watershed mouths. At the Elkhorn Slough National Estuarine Research Reserve, we will couple field- and lab-based studies with reactive transport models to quantify the co-variation of hydrological and biogeochemical subsurface processes in coastal watersheds, with a particular emphasis on identifying drivers on N retention and removal over different hydrologic regimes. Through this effort, we are extending the DOE Scientific Focus Area testbed approach to a novel and underrepresented coastal ecosystem.
Award Recipient(s)
  • University of California, Merced (PI: Zimmer, Margaret)