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Regulation causes nitrogen cycling discontinuities in Mediterranean rivers

River regulation has fundamentally altered large sections of the world’s river networks. The effects of dams on the structural properties of downstream reaches are well documented, but less is known about their effect on river ecosystem processes. We investigated the effect of dams on river nutrient cycling by comparing net uptake of total dissolved nitrogen (TDN), phosphorus (TDP) and organic carbon (DOC) in river reaches located upstream and downstream from three reservoir systems in the Ebro River basin (NE Iberian Peninsula). Increased hydromorphological stability, organic matter standing stocks and ecosystem metabolism below dams enhanced the whole-reach net uptake of TDN, but not that of TDP or DOC. Upstream from dams, river reaches tended to be at biogeochemical equilibrium (uptake. ≈. release) for all nutrients, whereas river reaches below dams acted as net sinks of TDN. Overall, our results suggest that flow regulation by dams may cause relevant N cycling discontinuities in rivers. Higher net N uptake capacity below dams could lead to reduced N export to downstream ecosystems. Incorporating these discontinuities could significantly improve predictive models of N cycling and transport in complex river networks

This research was financially supported by the Spanish Ministry of Economy and Competitiveness and FEDER through the project SCARCE (Consolider-Ingenio CSD2009-00065), and by the European Union through the FP7 project GLOBAQUA (Grant agreement No 603629)

Science of the Total Environment, 2016, vol. 540, p. 168-177

Elsevier

Author: von Schiller, Daniel
Aristi, Ibon
Ponsatí Sánchez, Lídia
Arroita, Maite
Acuña i Salazar, Vicenç
Elosegi, Arturo
Sabater, Sergi
Date: 2016 January 1
Abstract: River regulation has fundamentally altered large sections of the world’s river networks. The effects of dams on the structural properties of downstream reaches are well documented, but less is known about their effect on river ecosystem processes. We investigated the effect of dams on river nutrient cycling by comparing net uptake of total dissolved nitrogen (TDN), phosphorus (TDP) and organic carbon (DOC) in river reaches located upstream and downstream from three reservoir systems in the Ebro River basin (NE Iberian Peninsula). Increased hydromorphological stability, organic matter standing stocks and ecosystem metabolism below dams enhanced the whole-reach net uptake of TDN, but not that of TDP or DOC. Upstream from dams, river reaches tended to be at biogeochemical equilibrium (uptake. ≈. release) for all nutrients, whereas river reaches below dams acted as net sinks of TDN. Overall, our results suggest that flow regulation by dams may cause relevant N cycling discontinuities in rivers. Higher net N uptake capacity below dams could lead to reduced N export to downstream ecosystems. Incorporating these discontinuities could significantly improve predictive models of N cycling and transport in complex river networks
This research was financially supported by the Spanish Ministry of Economy and Competitiveness and FEDER through the project SCARCE (Consolider-Ingenio CSD2009-00065), and by the European Union through the FP7 project GLOBAQUA (Grant agreement No 603629)
Format: application/pdf
ISSN: 0048-9697
Document access: http://hdl.handle.net/10256/12600
Language: eng
Publisher: Elsevier
Collection: MICINN/PN 2009-2014/CSD2009-00065
Reproducció digital del document publicat a: http://dx.doi.org/10.1016/j.scitotenv.2015.07.017
Articles publicats (ICRA)
info:eu-repo/grantAgreement/EC/FP7/603629
Is part of: Science of the Total Environment, 2016, vol. 540, p. 168-177
Rights: Attribution-NonCommercial-NoDerivs 3.0 Spain
Rights URI: http://creativecommons.org/licenses/by-nc-nd/3.0/es/
Subject: Ecologia fluvial
Stream ecology
Cursos d’aigua -- Conservació
Stream conservation
Nitrogen
Nytrogen
Title: Regulation causes nitrogen cycling discontinuities in Mediterranean rivers
Type: info:eu-repo/semantics/article
Repository: DUGiDocs

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