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Biofilm Responses to Flow Regulation by Dams in Mediterranean Rivers

Dams regulate downstream hydrology and modify water quality, which in turn can impinge on the biota, especially in rivers naturally subject to large hydrological variability, such as those under Mediterranean climate. The effect of dams on biofilms was analysed in three tributaries (Cinca, Siurana and Montsant) of the Ebro River (NE Spain). We hypothesized that flow regulation would lead to lower spatial variability of biofilms on the streambed and to a decrease in their metabolic rate per unit biomass, especially during low flow periods. Biofilm characteristics were studied in five transects evenly spaced along river reaches upstream (control) and downstream (impact) of dams in each river, along with riverbed granulometry, hydraulics and water chemistry. Chlorophyll-a, respiratory activity, photosynthetic capacity and efficiency, and extracellular enzymatic activities (β-d-glucosidase, alkaline phosphatase and leucine-amino-peptidase) of epilithic biofilms were measured in different seasons. Spatial variability of chemical and biological variables was reduced downstream of the dams. Chlorophyll-a concentration, photosynthetic efficiency and respiration capacity were higher in impact than in control reaches, but generally, low inorganic phosphorus concentrations resulted in comparable phosphatase activities downstream and upstream of dams. On the other hand, β-d-glucosidase and leucine-amino-peptidase activities were higher at impact reaches. Biofilms were thicker and metabolically more active at the impact reaches, with higher ability to transform dissolved organic matter. Overall, results from this study provide evidence that dams can largely affect the structure and activity of river biofilms, with foreseeable important consequences for river ecosystem functioning

This research was supported by Spanish Ministry of Economy and Competitiveness through the projects SCARCE (Consolider-Ingenio 2010 CSD2009-00065) and CARBONET (CGL2011-30474-C02-01). We also want to acknowledge financial support in terms of predoctoral grants from the University of the Basque Country (I. Aristi), the Basque Government (M. Arroita), as well as a postdoctoral grant ‘Juan de la Cierva’ of the Spanish Ministry of Economy and Competitiveness (jci-2009-05604 and jci-2010-06397) (D von Schiller) and a Marie Curie European Reintegration Grant (PERG07-GA-2010-259219) (V Acuña)

© River Research and Applications, 2015, vol. 31, núm. 8, p. 1003-1016

Wiley

Autor: Ponsatí Sánchez, Lídia
Acuña i Salazar, Vicenç
Aristi, Ibon
Arroita, Maite
García-Berthou, Emili
von Schiller, Daniel
Elosegi, Arturo
Sabater, Sergi
Data: octubre 2015
Resum: Dams regulate downstream hydrology and modify water quality, which in turn can impinge on the biota, especially in rivers naturally subject to large hydrological variability, such as those under Mediterranean climate. The effect of dams on biofilms was analysed in three tributaries (Cinca, Siurana and Montsant) of the Ebro River (NE Spain). We hypothesized that flow regulation would lead to lower spatial variability of biofilms on the streambed and to a decrease in their metabolic rate per unit biomass, especially during low flow periods. Biofilm characteristics were studied in five transects evenly spaced along river reaches upstream (control) and downstream (impact) of dams in each river, along with riverbed granulometry, hydraulics and water chemistry. Chlorophyll-a, respiratory activity, photosynthetic capacity and efficiency, and extracellular enzymatic activities (β-d-glucosidase, alkaline phosphatase and leucine-amino-peptidase) of epilithic biofilms were measured in different seasons. Spatial variability of chemical and biological variables was reduced downstream of the dams. Chlorophyll-a concentration, photosynthetic efficiency and respiration capacity were higher in impact than in control reaches, but generally, low inorganic phosphorus concentrations resulted in comparable phosphatase activities downstream and upstream of dams. On the other hand, β-d-glucosidase and leucine-amino-peptidase activities were higher at impact reaches. Biofilms were thicker and metabolically more active at the impact reaches, with higher ability to transform dissolved organic matter. Overall, results from this study provide evidence that dams can largely affect the structure and activity of river biofilms, with foreseeable important consequences for river ecosystem functioning
This research was supported by Spanish Ministry of Economy and Competitiveness through the projects SCARCE (Consolider-Ingenio 2010 CSD2009-00065) and CARBONET (CGL2011-30474-C02-01). We also want to acknowledge financial support in terms of predoctoral grants from the University of the Basque Country (I. Aristi), the Basque Government (M. Arroita), as well as a postdoctoral grant ‘Juan de la Cierva’ of the Spanish Ministry of Economy and Competitiveness (jci-2009-05604 and jci-2010-06397) (D von Schiller) and a Marie Curie European Reintegration Grant (PERG07-GA-2010-259219) (V Acuña)
Format: application/pdf
ISSN: 1535-1459 (versió paper)
1535-1467 (versió electrònica)
Accés al document: http://hdl.handle.net/10256/12837
Llenguatge: eng
Editor: Wiley
Col·lecció: MICINN/PN 2009-2014/CSD2009-00065
MICINN/PN 2011-2013/CGL2011-30474-C02-01
Reproducció digital del document publicat a: http://dx.doi.org/10.1002/rra.2807
Articles publicats (CCAA)
info:eu-repo/grantAgreement/EC/FP7/259219
És part de: © River Research and Applications, 2015, vol. 31, núm. 8, p. 1003-1016
Drets: Tots els drets reservats
Matèria: Ecologia fluvial
Stream ecology
Cabal (Hidrologia) -- Regulació
Streamflow -- Regulation
Hidrologia
Hydrology
Títol: Biofilm Responses to Flow Regulation by Dams in Mediterranean Rivers
Tipus: info:eu-repo/semantics/article
Repositori: DUGiDocs

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