Estuaries and Coasts

, Volume 30, Issue 1, pp 54–65 | Cite as

Temporal variability in summertime bottom hypoxia in shallow areas of Mobile Bay, Alabama

  • Kyeong ParkEmail author
  • Choong-Ki Kim
  • William W. Schroeder


This paper addresses temporal variability in bottom hypoxia in broad shallow areas of Mobile Bay, Alabama. Time-series data collected in the summer of 2004 from one station (mean depth of 4 m) exhibit bottom dissolved oxygen (DO) variations associated with various time scales of hours to days. Despite a large velocity shear, stratification was strong enough to suppress vertical mixing most of the time. Bottom DO was closely related to the vertical salinity gradient (ΔS). Hypoxia seldom occurred when ΔS (over 2.5 m) was <2 psu and occurred almost all the time when ΔS was >8 psu in the absence of extreme events like hurricanes. Oxygen balance between vertical mixing and total oxygen demand was considered for bottom water from which oxygen demand and diffusive oxygen flux were estimated. The estimated decay rates at 20°C ranging between 0.175–0.322 d−1 and the corresponding oxygen consumption as large as 7.4 g O2 m−2 d−1 fall at the upper limit of previously reported ranges. The diffusive oxygen flux and the corresponding vertical diffusivity estimated for well mixed conditions range between 8.6–9.5 g O2 m−2 d−1 and 2.6–2.9 m2 d−1, respectively. Mobile Bay hypoxia is likely to be associated with a large oxygen demand, supported by both water column and sediment oxygen demands, so that oxygen supply from surface water during destratification events would be quickly exhausted to return to hypoxic conditions within a few hours to days after destratification events are terminated.


Bottom Water Destratification Event Freshwater Discharge Oxygen Balance Carbonaceous Biochemical Oxygen Demand 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Estuarine Research Federation 2007

Authors and Affiliations

  • Kyeong Park
    • 1
    Email author
  • Choong-Ki Kim
    • 1
  • William W. Schroeder
    • 2
  1. 1.Department of Marine SciencesUniversity of South Alabama, Dauphin Island Sea LabDauphin Island
  2. 2.Marine Science ProgramThe University of Alabama, Dauphin Island Sea LabDauphin Island

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