Epilithic biomass in a large gravel‐bed river (the Garonne, France): a manifestation of eutrophication?

Améziane, Thierry; Garabetian, Frédéric; Dalger, Daniel; Sauvage, Sabine; Dauta, A.; Capblancq, J.

doi:10.1002/rra.675

Cited by 28 publications

(17 citation statements)

References 27 publications

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“…The 2006 seasonal and site average concentration of chlorophyll-a in the periphyton biomass (343 mg/m 2 ± 71 (p = 0.05)) was not significantly higher than the 300 mg/m 2 value below which the majority of published periphyton chlorophyll-a concentrations fall (Ameziane et al 2002). It was, however, significantly higher than the historic average in the sampled reach of the Bow River.…”

Section: Discussioncontrasting

confidence: 58%

Modelling aquatic vegetation and dissolved oxygen after a flood event in the Bow River, Alberta, Canada

et al. 2009

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Traditionally, macrophyte density has been considered the primary factor affecting the large dissolved oxygen fluctuations in the Bow River. After a major flood event scoured macrophytes in 2005, and subsequently changed river dynamics, the City of Calgary needed to update their predictive computer model for water quality to reflect the new conditions, which led to this study. A 2006 aquatic vegetation survey was also completed to assess post-flood conditions. The survey found that the average macrophyte dry weight was much lower (28 g/m 2 ± 100 (p = 0.05)) than the historic average of 241 g/m 2 ± 29, while the average periphyton chlorophyll-a concentration was higher (343 mg/m 2 ± 71) than the historic average (158 mg/m 2 ± 17)). Dissolved oxygen (DO) fluctuations were similar to pre-flood levels despite changes in the dominant vegetation. Using the results of this survey, the significant and previously unrecognized effects of periphyton diurnal processes on DO concentrations in the Bow River were identified and the Bow River water quality model (BRWQM) was recalibrated to reflect these findings. Adjustments were made to the BRWQM's periphyton submodel to account for the more dominant role played by these organisms in river processes, and a competitive shading factor between macrophytes and periphyton was also introduced to more accurately model the species' competition for available sunlight. This newly calibrated and validated version of BRWQM was tested and found capable of predicting the occurrence of low DO concentrations in the Bow River and can provide a useful tool for forecasting the water quality effects of the city's planned wastewater infrastructure expansion.Résumé : Traditionnellement, la densité en macrophytes a été considérée comme étant le principal facteur relié à de fortes fluctuations en oxygène dissous dans la rivière Bow. Après le lessivage des macrophytes par une inondation majeure en 2005 et le changement subséquent dans la dynamique de la rivière, la Ville de Calgary a demandé la mise à niveau de son modèle informatique prédictif sur la qualité de l'eau pour les nouvelles conditions déterminées lors d'un relevé de la végé-tation aquatique en 2006. Le relevé a permis de découvrir que le poids sec moyen de macrophytes (28 g/m 2 ± 100 (p = 0.05)) beaucoup plus bas que la moyenne historique de 241 g/m 2 ± 29 alors que la moyenne de la concentration en chlorophylle-a du périphyton était plus élevée (343 mg/m 2 ± 71) que la moyenne historique de 158 mg/m 2 ± 17. Les fluctuations de la teneur en oxygène dissous étaient similaires aux teneurs avant l'inondation malgré les changements dans la végéta-tion dominante. Les effets importants, et antérieurement inconnus, des processus diurnes du périphyton sur les concentrations en oxygène dissous ont été identifiés et le modèle de la qualité de l'eau de la rivière Bow (« BRWQM ») a été étalonné de nouveau pour refléter ces conclusions. Le sous-modèle de périphyton du « BRWQM » a été ajusté afin de tenir compte du rôle plus dominant joué par ces organi...

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Section: Discussioncontrasting

confidence: 58%

Modelling aquatic vegetation and dissolved oxygen after a flood event in the Bow River, Alberta, Canada

et al. 2009

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“…The nutrient concentrations in the Garonne River generally range for a total of N concentrations from 0.7 to 32 mg l -1 , for a total of P concentrations from 0.1 to 2.5 mg l -1 , respectively (Ameziane et al, 2002;Leflaive et al, 2008;Muylaert et al, 2009;Sow, unpublished data). We used GF/C filtered water river as a non-nutrient-enriched treatment (NAT).…”

Section: Experimental Designmentioning

confidence: 97%

Short-term effects of nutrient enrichment on river biofilm: N–NO3 − uptake rate and response of meiofauna

et al. 2014

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Biofilms play a key role in self-depuration processes in rivers. Whilst meiofauna is known to be abundant within river phototrophic biofilms and to perform both grazing and bioturbation within these matrixes, it is still unknown whether the activity of biofilm-associated meiofauna can influence the ability of biofilms to improve river water quality. In this study, we explored the effects of nutrient enrichment on river biofilm N-NO 3 -uptake rates and associated meiofauna in microcosms for 5 days under nutrientenriched/non-enriched conditions. Short-time nutrient enrichment stimulated biofilm-associated bacterial and rotifer density, as well as the biofilm uptake rates of N-NO 3 -, but not algal biomass. Under nonenriched conditions, N-NO 3 -uptake rate tended to reach a plateau around 104.2 lg g -1 AFDM h -1 . At higher N-NO 3 -concentrations, realised under enrichment, N-NO 3 -uptake rate seemed to increase linearly, reaching up to 439.2 lg g -1 AFDM h -1 . Our results showed a rapid response of rotifers to nitrate enrichment and suggest a possible link between bacteria-meiofauna interactions and the short-term N uptake capacity of biofilms.

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“…On each sampling occasion, 12 immerged cobbles (mean diameter: 10 cm) were collected underwater using plastic bags to prevent any biofilm detachment during removal. To consider water level changes and depth where the biofilm typically develops (Ameziane et al, 2002), cobbles were collected on a crosssection from a reference point in the riverside so that water height above cobbles remained between 30 and 50 cm. Collected cobbles were transported to the laboratory within 2 h in cool boxes with minimal disturbance.…”

Section: Study Site and Sample Collectionmentioning

confidence: 99%

Response of biofilm-dwelling nematodes to habitat changes in the Garonne River, France: influence of hydrodynamics and microalgal availability

et al. 2011

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Lotic epilithic biofilms are submitted to seasonal disturbances (e.g. flood events, self-detachment), which influence the biomass, diversity and viability of their algal and bacterial communities. The objective of this study is to examine whether (1) biofilm-dwelling nematodes respond to such seasonal changes in terms of diversity and community structure, (2) nematode species and feeding-types distribution respond to the varied trophic situations within the biofilm, since variations in biofilm microalgal composition may represent a variation in available food. The biofilm-dwelling nematode community was monitored in a temperate river over an 18 month period with a high sampling frequency. These data were linked to environmental abiotic and biofilm biotic factors. Nematode density was positively correlated to biofilm and microalgal biomass, but was dampened by floods. A clear seasonal pattern of the community was detected (summer shift), so that two nematode groups stand out: (1) the epistratefeeders Chromadorina bioculata (Schultze in Carus, 1857) and Chromadorina viridis (Linstow, 1876) were primarily related to diatom availability, and dominated the nematode assemblage most of the time, (2) seven species from various feeding types (deposit-feeders, suction-feeders and chewers) grew mainly under summer conditions concomitantly to a change of biofilm trophic status and microalgal composition. Overall, the results suggested that, in addition to abiotic disturbances, the availability of potential preys in the biofilm might represent an important driver of nematode community patterns.

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Epilithic biomass in a large gravel‐bed river (the Garonne, France): a manifestation of eutrophication?

Cited by 28 publications

References 27 publications

Modelling aquatic vegetation and dissolved oxygen after a flood event in the Bow River, Alberta, Canada

Modelling aquatic vegetation and dissolved oxygen after a flood event in the Bow River, Alberta, Canada

Short-term effects of nutrient enrichment on river biofilm: N–NO3 − uptake rate and response of meiofauna

Response of biofilm-dwelling nematodes to habitat changes in the Garonne River, France: influence of hydrodynamics and microalgal availability

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