Increased sediment oxygen flux in lakes and reservoirs: The impact of hypolimnetic oxygenation. Issue 6 (15th June 2017)

• Record Type: Journal Article
• Authors: Bierlein, Kevin A.; Rezvani, Maryam; Socolofsky, Scott A.; Bryant, Lee D.; Wüest, Alfred; Little, John C.
• Is Part Of: Water resources research. Volume 53:Issue 6(2017)
• Page Start: 4876
• Page End: 4890
• Publication Date: 2017-06-15
• Subjects: diffusive boundary layer -- bubble plume -- interfacial flux -- mass transfer -- sediment oxygen demand -- turbulence; Hydrology -- Periodicals; 333.91
• DOI: 10.1002/2016WR019850
• Languages: English
• ISSNs: 0043-1397

Abstract

Abstract: Hypolimnetic oxygenation is an increasingly common lake management strategy for mitigating hypoxia/anoxia and associated deleterious effects on water quality. A common effect of oxygenation is increased oxygen consumption in the hypolimnion and predicting the magnitude of this increase is the crux of effective oxygenation system design. Simultaneous measurements of sediment oxygen flux (JO2 ) and turbulence in the bottom boundary layer of two oxygenated lakes were used to investigate the impact of oxygenation on JO2 . Oxygenation increased JO2 in both lakes by increasing the bulk oxygen concentration, which in turn steepens the diffusive gradient across the diffusive boundary layer. At high flow rates, the diffusive boundary layer thickness decreased as well. A transect along one of the lakes showed JO2 to be spatially quite variable, with near‐field and far‐field JO2 differing by a factor of 4. Using these in situ measurements, physical models of interfacial flux were compared to microprofile‐derived JO2 to determine which models adequately predict JO2 in oxygenated lakes. Models based on friction velocity, turbulence dissipation rate, and the integral scale of turbulence agreed with microprofile‐derived JO2 in both lakes. These models could potentially be used to predict oxygenation‐induced oxygen flux and improve oxygenation system design methods for a broad range of reservoir systems. Key Points: Oxygenation increases sediment oxygen flux due to elevated oxygen concentrations at the SWI and thinning of the DBL In situ measurements are compared to predictive models of sediment oxygen flux Three interfacial flux models agree with in situ sediment oxygen flux measurements