The Role of Allochthonous Inputs of Dissolved Organic Carbon on the Hypolimnetic Oxygen Content of Reservoirs |
| |
Authors: | Rafael Marcé Enrique Moreno-Ostos Pilar López Joan Armengol |
| |
Institution: | (1) Department of Ecology, University of Barcelona, Diagonal 645, 08028 Barcelona, Spain |
| |
Abstract: | Hypolimnetic oxygen content in lentic ecosystems has traditionally been modeled as a function of variables measured at the
epilimnion, or that are supposed to drive epilimnetic processes, like total phosphorus load. However, in man-made reservoirs
the river inflow can plunge into deep layers, directly linking the hypolimnion with the surrounding watershed. In these circumstances,
organic matter carried by the river can influence the hypolimnetic oxygen content without important intervention of epilimnetic
processes. Taking long-term data from two reservoirs in Spain, we applied an empirical regression approach to show that the
dissolved organic matter carried by the river is the main driver shaping the hypolimnetic oxygen content. By contrast, typical
variables commonly included in the modeling of the oxygen content in the hypolimnion (nutrient concentrations, chlorophyll
a, and dissolved organic carbon measured in the water column) did not show any significant correlation. Interpretations from
this regression approach were supported by a comparison between the monthly oxygen consumption in the hypolimnion and the
monthly dissolved organic carbon load from the river inflow. We also revisited the prediction of the year-to-year variability
of the Nürnberg’s anoxic factor in four reservoirs from Spain and the USA, explicitly including the allochthonous sources
in the equations. These sources were significant predictors of the anoxic factor, especially in those systems subject to relatively
high human impact. Thus, effects of allochthonous dissolved organic carbon should always be considered in empirical modeling
and management of reservoir hypolimnetic processes related to oxygen content (for example, anoxia, nutrient internal loading,
or phosphorus cycle resilience). |
| |
Keywords: | Labile organic carbon C:N ratio Chloride Anoxic factor Empirical modeling DOC Reservoir Hypolimnion Oxygen |
本文献已被 SpringerLink 等数据库收录! |
|