Citation:

Jarvis, B., Jim Hagy, J. Lehrter, M. Murrell, D. Yates, AND G. Craven. Modeling Diel Oxygen Dynamics and Ecosystem Metabolism in Weeks Bay, Alabama. Weeks Bay Research Symposium, Weeks Bay, AL, August 04 - 05, 2016.

Impact/Purpose:

This abstract is being submitted for a presentation at the Weeks Bay Research Symposium, and is intended to provide an update on the ongoing research being conducted in Weeks Bay to other researchers.

Description:

Weeks Bay is a shallow eutrophic estuary that exhibits frequent summertime diel-cycling hypoxia and periods of dissolved oxygen (DO) oversaturation during the day. Diel DO dynamics in shallow estuaries like Weeks Bay are complex, and may be influenced by wind forcing, vertical and horizontal mixing, variation in freshwater inflow, cloud cover, and temperature. This study utilized continuous DO monitoring and 3-D hydrodynamic and water quality models to examine physical and biological controls on DO dynamics in Weeks Bay. We used coupled Environmental Fluid Dynamics Code (EFDC) and Water Quality Analysis Simulation Program (WASP) models to simulate hydrodynamics and water quality for May-Oct 2015. Observed vertical DO gradients varied on a diel basis, with larger amplitude variations at depth relative to the surface, underscoring the importance of benthic production and respiration as a driver of ecosystem metabolism in Weeks Bay. Hydrodynamic and water quality models simulated seasonal and event-driven dynamics, but underestimated the amplitude of daily DO fluctuations, particularly in bottom waters. These results emphasize the need for models to accurately resolve the partitioning of system metabolism between the benthos and water column to improve model predictions of dynamic ecosystem processes.

Record Details: