Freshwater Tidal Zone

Nitrogen Dynamics in the Tidal Freshwater Zone

White Clay Creek (courtesy of A. Sawyer)

My students and I are working with Audrey Sawyer (OSU) and her students to examine how tidal fluctuations within the freshwater portion of a river impact nitrogen processing and eventual export. This work is taking place within the tidal portion of White Clay Creek, which is part of the Christina River CZO. Using transects of nested piezometers our goal is to quantify the groundwater-surface water exchange and link these hydrodynamics to the nitrogen biogeochemistry in the groundwater, pore water and stream. Sampling for this project started in the summer of 2014 and formed the basis of Cole Musial’s Master’s Thesis (Univ Kentucky), Sam Bray’s senior project (CC), and a portion of Deon Knights’ Master work (Ohio State Univ). We returned to White Clay Creek in August of 2015 with several of Audrey’s students to resample the pore waters, install redox sensors in the stream sediments, and get a better understanding of how tidal fluctations vary with distance from the Delaware Bay. This project is funded by a NSF Hydrologic Sciences grant (NSF EAR 1446763).

Publications & Theses: 

  • Musial, C.T., A.H. Sawyer, R.T. Barnes, S. Bray, & D. Knights#. 2015. Dynamic surface water-groundwater exchange in tidal freshwater zones: Insights from the Christina River Basin (Delaware, USA). Hydrological Processes, DOI: 10.1002/hyp.10623
  • Knights, D., A. Sawyer, R.T. Barnes, C. Musial, &  S. Bray. 2017. Tidal controls on streambed denitrification along a tidal freshwater zone. Water Resources Research, DOI: 10.1002/2016WR019405
  • Delaney Tight (2018) How Do Tides Affect Nitrogen Cycling in Coastal Riparian Aquifers?
  • Wallace, C.D., A.H. Sawyer, & R.T. Barnes. Spectral analysis of continuous redox data reveals geochemical processes near the stream-aquifer interface, in press, Hydrological Processes

White Oak Creek Sampling Trip | Jacksonville, NC | August 2017


Emily Komie (CC ’18 EV Major, Film Minor) & Will Stockton (CC ’19, Film Major) made this short movie about our work on White Clay Creek:

White Clay Creek from Emily Komie on Vimeo.

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