Hypolimnetic Oxygen Depletion in Eutrophic Lakes

The oxygen-consuming processes in the hypolimnia of freshwater lakes leading to deep-water anoxia are still not well understood, thereby constraining suitable management concepts. This study presents data obtained from 11 eutrophic lakes and suggests a model describing the consumption of dissolved oxygen (O-2) in the hypolimnia of eutrophic lakes as a result of only two fundamental processes: O-2 is consumed (i) by settled organic material at the sediment surface and (ii) by reduced substances diffusing from the sediment. Apart from a lake's productivity, its benthic O-2 consumption depends on the O-2 concentration in the water overlying the sediment and the molecular O-2 diffusion to the sediment. On the basis of observational evidence of long-term monitoring data from 11 eutrophic lakes, we found that the areal hypolimnetic mineralization rate ranging from 0.47 to 1.31 g of O-2 m(-2) d(-1) (average 0.90 +/- 0.30) is a function of (i) a benthic flux of reduced substances (0.37 +/- 0.12 g of O-2 m(-2) d(-1)) and (ii) an O-2 consumption which linearly increases with the mean hypolimnion thickness (z(H)) up to similar to 25 m. This model predicting and interpreting the response of lakes and reservoirs to restoration measures. has important implications for predicting and interpreting the response of lakes and reservoirs to restoration measures.


Published in:
Environmental Science & Technology, 46, 18, 9964-9971
Year:
2012
Publisher:
Washington, Amer Chemical Soc
ISSN:
0013-936X
Laboratories:




 Record created 2013-02-27, last modified 2018-09-13


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