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 a...

Full description

Saved in:

Bibliographic Details
Published in:	River research and applications 2015-10, Vol.31 (8), p.1003-1016
Main Authors:	Ponsatí, L, Acuña, V, Aristi, I, Arroita, M, García‐Berthou, E, Schiller, D, Elosegi, A, Sabater, S
Format:	Article
Language:	eng
Subjects:	alkaline phosphatase beta-glucosidase biofilm Biofilms biomass chlorophyll Control Dams dams (hydrology) dissolved organic matter ecosystem functioning ecosystems enzyme activity epilithic biofilm fluid mechanics Freshwater Hydraulics hydrochemistry Hydrology inorganic phosphorus leucyl aminopeptidase Mediterranean climate photosynthesis photosynthetic efficiency Rivers seasons stream channels Upstream Water quality
Online Access:	Request full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	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. Copyright © 2014 John Wiley & Sons, Ltd.
ISSN:	1535-1459 1535-1467