Biofilm Responses to Flow Regulation by Dams in Mediterranean Rivers

Ponsatí, Lídia; Acuña, Vicenç; Aristi, Ibon; Arroita, Maite; García‐Berthou, Emili; Schiller, Daniel von; Elosegi, Arturo; Sabater, Sergi

doi:10.1002/rra.2807

Cited by 27 publications

(31 citation statements)

References 52 publications

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“…As shown in this study, SBT events can modify key components of ecosystem structure and function. An extreme magnitude or frequency of events could highly modify organic matter decomposition processes, and primary or secondary production in the system, thus having severe ecosystem consequences (Jones et al, 2012;Aristi et al, 2014;Ponsatí et al, 2015). However, the near-natural characteristics of events in our study case avoided dramatic unexpected ecosystem impacts.…”

Section: Discussionmentioning

confidence: 84%

Ecological Assessment of a Sediment By‐pass Tunnel on a Receiving Stream in Switzerland

Martín

Doering

Robinson

2017

River Research & Apps

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Reservoir siltation is a major problem worldwide, decreasing reservoir storage capacity, trapping entrained sediment, and altering the natural sediment regime. Sediment By-pass Tunnels (SBTs) are used to connect reservoirs with downstream receiving waters during high flows to reduce sediment accumulation in the reservoir. When operating, large volumes of sediment-laden waters are released into the receiving river for short periods of time (h). The aim of this study was to assess the impact of SBT events on the downstream riverine ecosystem. We measured physico-chemical properties, sediment respiration, periphyton biomass and chlorophyll-a, and macroinvertebrate assemblages along a 5-km stretch of river during the first two years of SBT operation. During the study, five major SBT events occurred. Few changes were found in physico-chemical properties, mainly due to the input of tributaries entering the system. Results showed a clear reduction in sediment respiration, an indicator of ecosystem metabolism, especially after large SBT events. Periphyton levels and macroinvertebrate density/richness also decreased after SBT events. A non-metric multidimensional scaling distinguished both temporal and spatial shifts in macroinvertebrate assemblages after SBT events, being related to downstream distance and SBT event magnitude. In summary, SBT events acted as a pulse disturbance, similarly to natural floods, followed by recovery of measured ecosystem indicators. Sediment By-pass Tunnel events can enhance sediment and flow connectivity, although the magnitude and frequency of operations should be controlled to prevent catastrophic disturbances.

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Section: Discussionmentioning

confidence: 84%

Ecological Assessment of a Sediment By‐pass Tunnel on a Receiving Stream in Switzerland

Martín

Doering

Robinson

2017

River Research & Apps

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“…Alexander et al ., ). Therefore, the response to pollution can differ from the scale of individual components such as biofilm to the scale of the whole ecosystem, as already shown for other environmental pressures such as flow regulation (Aristi et al ., ; Ponsatí et al ., ).…”

Section: Introductionmentioning

confidence: 97%

“…The toxic contaminants entering fresh waters via WWTP effluents can have direct detrimental effects on aquatic life (Hernando et al, 2006;de Castro-Catala et al, 2014), especially when they occur in mixtures (Cleuvers, 2003). Toxic contaminants reduce the abundance, affect the composition of biofilms (Wilson et al, 2003;Ponsat ı et al, In revision) and invertebrate communities (Muñoz et al, 2009;Alexander et al, 2013;Clements, Cadmus & Brinkman, 2013) and can also affect the rates of ecosystem processes (Bundschuh et al, 2009;Moreirinha et al, 2011;Rosi-Marshall et al, 2013). Autotrophic processes seem to be more sensitive to WWTP pollutants than heterotrophic processes (Proia et al, 2013;Corcoll et al, 2014), but the reasons behind these differences are still far from clear.…”

Section: Introductionmentioning

confidence: 99%

Mixed effects of effluents from a wastewater treatment plant on river ecosystem metabolism: subsidy or stress?

et al. 2015

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SUMMARY1. The effluents of wastewater treatment plants (WWTPs) include a complex mixture of nutrients and pollutants. Nutrients can subsidise autotrophic and heterotrophic organisms, while toxic pollutants can act as stressors, depending, for instance, on their concentration and interactions in the environment. Hence, it is difficult to predict the overall effect of WWTP effluents on river ecosystem functioning. 2. We assessed the effects of WWTP effluents on river biofilms and ecosystem metabolism in one river segment upstream from a WWTP and three segments downstream from the WWTP and following a pollution gradient. 3. The photosynthetic capacity and enzymatic activity of biofilms showed no change, with the exception of leucine aminopeptidase, which followed the pollution gradient most likely driven by changes in organic matter availability. The effluent produced mixed effects on ecosystem-scale metabolism. It promoted respiration (subsidy effect), probably as a consequence of enhanced availability of organic matter. On the other hand, and despite enhanced nutrient concentrations, photosynthesis-irradiance relationships showed that the effluent partly decoupled primary production from light availability, thus suggesting a stress effect. 4. Overall, WWTP effluents can alter the balance between autotrophic and heterotrophic processes and produce spatial discontinuities in ecosystem functioning along rivers as a consequence of the mixed contribution of stressors and subsidisers.

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“…water discharge and sediment load; e.g. Williams and Wolman, 1984;Batalla et al, 2004) and have effects on the functioning of fluvial ecosystems (Ward and Stanford, 1979;Aristi et al, 2014;Ponsatí et al, 2014). River regulation decreases the magnitude and frequency of floods, annual runoff is altered and seasonal and daily distribution of flows changes downstream from reservoirs, having large effects on the river ecology (Petts, 1984;Belmar et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Hydrological characterization of dammed rivers in the NW Mediterranean region

2015

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Abstract:Water scarcity and climatic variability in the Mediterranean region have traditionally required the construction of dams to guarantee water supply for irrigation, industrial and urban uses and hydropower production. Reservoirs affect the hydrology of the river downstream, but the magnitude and persistence of these effects are still poorly unknown. Understanding the magnitude of these effects is the objective of this paper, in which we analyse the flow regimes of twelve rivers located in the NW Mediterranean region. Different temporal scales (daily, monthly and annual) are used for the analysis and also to estimate flow variables associated with flow magnitude, frequency, duration and variability. It is shown that dams alter the hydrological regime of most of the studied rivers, with special influence on monthly flows and flood magnitude and frequency. The most altered rivers (Muga and Siurana, NE Iberian Peninsula) experience a complete overturn in their flow regime with, for instance, flood reduction reaching up to 76% for the 2-year flood event. Other rivers showed lower changes in hydrology (e.g. Orb and Têt). Annual runoff showed a pattern of decrease in all the studied rivers (regulated and non-regulated) indicating that besides dams (i.e. reservoir evaporation), other factors likely affect water yield. A general recovery downstream from dams is also observed at all temporal scales, mainly because of the inflow from tributaries. Although dams have a clear impact on the hydrology of Mediterranean rivers, water withdrawals and diversions for irrigation and other consumptive uses also affected the hydrological patterns.

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Biofilm Responses to Flow Regulation by Dams in Mediterranean Rivers

Cited by 27 publications

References 52 publications

Ecological Assessment of a Sediment By‐pass Tunnel on a Receiving Stream in Switzerland

Ecological Assessment of a Sediment By‐pass Tunnel on a Receiving Stream in Switzerland

Mixed effects of effluents from a wastewater treatment plant on river ecosystem metabolism: subsidy or stress?

Hydrological characterization of dammed rivers in the NW Mediterranean region

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