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Project Meeting / Activity Group 3 Diatoms - Analysis of the French diatom dataset for Rebecca issues: Effects of the natural variation and of nutrients causing eutrophication on the diatom communities

Abstract : This meeting organized by the University of Bratislava is a coupled Rebecca / WP4 Meeting and WP4 / GIG co-ordinators joint meeting. The scientific talks about step results are presented to all activity groups, in order: 1) to make a good link between the different WGs of the project ; 2) to allow a true exchange of knowledge between activity groups, with discussions on both specific and generic issues ; and 3) to make the link between the FP6 project and the coordinators of Geographical Intercalibration Groups. The present t alk, given by Cemagref, makes the point of the work done on the diatom compartment from the beginning of the project, based on the analyses of French national dataset. The first point concerns the investigation of biotypology. 11 different biotypes have been identified, 5 of them being driven by different natural abiotic conditions(i.e. 5 reference biotypes) and 6 other biotypes being mainly structured under influence of different kind and intensities of anthopogenic alteration. Another focus concerned the reduction of species number aiming at a simplification of national datasets without loosing structuring ecological information. With the help of a structuring index set-up by our research team (the GSI), it was possible to reduce the number of species to 1/3 of the total (from 941 to 353) without loosing ecological structuring information. Then was presented the progress of the WFD implementation under French conditions. 234 true reference sites have been selected, divided into 5 natural biotypes. This natural framework has been then used to set-up a national assessment system using BDI. Assessment grids have been built by natural region (key values for quality class limits by HER, EQR calculations on the basis of the convenient reference level per homogenous natural zone). The last part of the talk concerned a very hard point, knowing the taxonomic harmonization work carried out by Michel Coste on a regroument of 4 national diatom datasets, and the coding of a common diatom abbreviation list under an Omnidia standard, allowing to make joint and homogenous analyses of the 4 national datasets (work just finished). Such regrouped analyses will begin in the next weeks.
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https://hal.inrae.fr/hal-02610322
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Submitted on : Saturday, May 16, 2020 - 7:38:37 PM
Last modification on : Thursday, June 3, 2021 - 5:34:03 PM

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  • HAL Id : hal-02610322, version 1
  • IRSTEA : PUB00064445

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François Delmas, Juliette Tison-Rosebery, Y.S. Park, J.G. Wasson, Michel Coste. Project Meeting / Activity Group 3 Diatoms - Analysis of the French diatom dataset for Rebecca issues: Effects of the natural variation and of nutrients causing eutrophication on the diatom communities. 6th FP REBECCA Project - WP4 - Activity Group 3 / Diatom Workshop, Oct 2005, Bratislava, Slovakia. pp.37. ⟨hal-02610322⟩

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