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Temporal and Spatial Dynamics of Diel-Cycling Hypoxia in Four Northern Gulf of Mexico Estuaries
Citation:
Jarvis, B., Jim Hagy, J. Lehrter, M. Murrell, D. Yates, AND D. Beddick. Temporal and Spatial Dynamics of Diel-Cycling Hypoxia in Four Northern Gulf of Mexico Estuaries. Bays and Bayous Symposium, Mobile, Al, December 02 - 03, 2014.
Impact/Purpose:
The presentation described in this abstract will be delivered at the Bays and Bayous symposium held Dec 2-3 in Mobile AL. This presentation will describe results of oxygen dynamics evaluated as part of GED's ADOS project.
Description:
Eutrophication of coastal ecosystems has accelerated in recent decades due to population growth and associated nutrient pollution, resulting in increased incidence of hypoxia. Shallow and highly productive estuaries and embayments are particularly susceptible to diel-cycling hypoxia, associated with day-night cycles of production and respiration, which can result in a range of dissolved oxygen (DO) conditions from anoxia to super-saturation within a single day. Diel oxygen dynamics in these systems are complex, and may be influenced by wind forcing, vertical and horizontal flushing due to tides, freshwater inflow, cloud cover and temperature. This study assessed the spatial and temporal extent of episodic and cyclic low DO events in four northern Gulf of Mexico Estuaries (Weeks Bay, AL; Wolf Bay, AL; Fowl River, AL; and St. Louis Bay, MS). Dissolved oxygen varied strongly on a diel basis in all four systems. Periods of low oxygen longer than 24 hours were observed in both Weeks Bay and Wolf Bay. The duration and persistence of diel-hypoxia further varied in response to changing salinity regimes and regional weather. These results underscore the importance of combining fixed site continuous monitoring data with spatial hydrographic surveys to accurately resolve DO dynamics in shallow estuarine systems.