Primary production in headwater streams of the Seine basin: The Grand Morin river case study

Centre de Géosciences, UMR Sisyphe, ENSMP, 35, rue Saint-Honoré, F-77305 Fontainebleau, France.
Science of The Total Environment (Impact Factor: 4.1). 05/2007; 375(1-3):98-109. DOI: 10.1016/j.scitotenv.2006.12.015
Source: PubMed


Periphytic biomass has an important influence on the water quality of many shallow streams. The purpose of this paper is to synthesize the knowledge obtained on periphyton during the PIREN Seine research program. Periphyton was sampled using chl a measurements by acetone extraction and oxygen measurements with microelectrodes. The experiments reveal the presence of an important fixed biomass ranging between 123 and 850 mgchl a m(-2) and the mean gross production (photosynthesis) is shown to range between 180 and 315 mgC m(-2) h(-1). An independent approach was performed using the ProSe model, which simulates transport and biogeochemical processes in 22 km of the Grand Morin stream. A strong agreement between in situ measurements and the model results was obtained. The gross production obtained using ProSe is 220 mgC m(-2) h(-1) for the periphyton, which matches the experimental data. Although the net photosynthetic activity of the phytoplankton (0.84 gC gC(-1) d(-1)) is higher than the periphytic one (0.33 gC gC(-1) d(-1)), the absolute periphytic activity is greater since the mean biomass (3.4 gC m(-)(2)) is 10 times higher than the phytoplanktonic one (0.3 gC m(-2)), due to the short residence time of the water body (1.5d).

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    • "The hydrodynamic and biogeochemical model ProSe was firstly developed to simulate the impacts of human activities on nitrogenous and phosphorous pollutions in the Seine River and its tributaries (Even et al., 1998; Flipo et al., 2007; Even et al., 2007). All mathematical equations used by the ProSe model to simulate the river flowing, pollutant advection and other biogeochemical parameters are provided by Even et al. (1998). "
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    ABSTRACT: Assessing the fate of endocrine disrupting compounds (EDC) in the environment is currently a key issue for determining their impacts on aquatic ecosystems. The 4 nonylphenol (4-NP) is a well known EDC. It results from the biodegradation of surfactant nonylphenol ethoxylates (NPEO). Biodegradation mechanisms of NPEO are well documented (Giger et al. 2009) but their rate constants have been mainly determined through laboratory experiments. To our knowledge only Jonkers et al. (2005) evaluate NPEO biodegradation rate constants according to field measurements. Their study was carried out in an estuary (salt water) and has to be confirmed for freshwater. This study aims at evaluating the in-situ biodegradation of 4-NP, nonylphenol monoethoxylate (NP1EO) and nonylphenolic acetic acid (NP1EC). Two innovative sampling campaigns were carried out on the Seine River in July and September 2011, from Maisons-Laffitte to Triel-sur-Seine (along a 40km-transect downstream of Paris City). Their results were used for calibrating a sub-model of NPEO biodegradation of the hydrodynamic-biogeochemical model of the Seine River (PROSE, Even et al. 1998). Sampling times were estimated according to the Seine River velocity in order to follow the same volume of water. Simultaneously, during the September sampling campaign, small scale spatial and temporal variabilities of nonylphenolic compounds concentrations were assessed. Biodegradation rate constants of 4-NP, NP1EO and NP1EC between July and September varied greatly. Although the biodegradation rate constants in July were especially high (higher than 1 d 1), those obtained in September were smaller but consistent with the literature. This variability is probably linked to the biogeochemical behaviour of the Seine River. Indeed, the July sampling campaign took place at the end of an algal bloom leading to an unusual bacterial biomass while the September campaign was carried out during an "usual" biogeochemical state. This study provides relevant information regarding biodegradation rate constants of alkylphenols in an aquatic environment. Such data may be very helpful in the future to better understand the fate and transfer of nonylphenolic compounds at the catchment basin scale.
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    • "À1 Flipo et al. (2007) "
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    ABSTRACT: In-stream benthic processes can play a significant role on the water quality of overlying waters flowing through a river network. In order to better understand and quantify the fate of nutrients (nitrogen, phosphorus and silica) during their travel through the river continuum, a deterministic benthic sub-model was developed with the purpose of being connected to a drainage network model. This benthic sub-model resolves the differential equations representing early diagenesis in the sediment, linking the sedimentation rate of organic matter onto the sediment to the resulting flux of nutrients across the sediment–water interface. The model has been developed for conditions where sedimentation prevails as well as for situations where net erosion prevents the built-up of a significant sediment layer and where only a biofilm can develop, attached to solid substrates. The benthic model was tested independently of the main water column biological–hydrological model to which it is intended to be coupled. For this, three case studies were chosen from the literature representing various sedimentation/erosion conditions: the 8th order river Seine (France), the water storage basin of Méry s/Oise (France), and the headwater stream Orneau (Belgium). The general benthic model has been validated for ammonium, nitrate, oxygen and phosphorus fluxes across the sediment–water interface. The capability of the model to correctly predict the observed nutrients profiles within the sediment was also validated for organic carbon, ammonium and phosphorus. An uncertainty analysis showed that using two modelling objectives (observed fluxes and concentration profiles in the sediment) strongly reduces the uncertainty in parameters calibration. A sensitivity analysis illustrated the complexity of the interacting reactions driving each variable, and justifies the usefulness of the model as a tool for understanding and predicting the behaviour of the benthic compartment of river systems.
    Journal of Hydrology 01/2007; 341(1-2):55-78. DOI:10.1016/j.jhydrol.2007.05.001 · 3.05 Impact Factor
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