Suchergebnisse

International audience ; The increasing contamination by micropollutants in freshwater systems has become a major problem in modern societies, giving rise to toxicological, sanitary and economical concerns. In 2010 the French government adopted a plan for a 50% reduction over 10 years in the use of pesticides which promotes research on contamination monitoring. Diatom bio-indication tools in rivers have been standardized and normalized (AFNOR NFT 90 354 ; CEN – EN 13946 & EN 14407) and are adapted to assess nutrient and organic matter levels. However these indicators do not assess micropollutants contamination despite diatoms being known to be sensitive to pesticide pollution. The objective of this study is to assess whether bio-indicators based on diatom communities could be developed to assess the impact of pesticide contamination, especially herbicides, on freshwater ecosystems quality. The hypothesis that increasing herbicide concentration reduces diatom diversity wastested on a diatom data set from the French Water Framework Directive monitoring network. The data set includes more than 2000 samples from 14 ecoregions from eastern France over the period 2000 - 2008. To each sample corresponds a list of diatom taxa and 531micropollutants (herbicides, insecticides, fungicides, heavy metals and organic micropollutants) concentration measurements. Diatom diversity was calculated by means of2 classic indices: Shannon's H' (Shannon, 1948) and Simpson's D (Simpson, 1949) and 3taxonomic distinctness indices: ?, ?* and ?+ (Clarke and Warwick, 1998). This poster describes preliminary results which may lead to new bio-indication metrics adapted to pesticide contamination.

International audience ; The increasing contamination by micropollutants in freshwater systems has become a major problem in modern societies, giving rise to toxicological, sanitary and economical concerns. In 2010 the French government adopted a plan for a 50% reduction over 10 years in the use of pesticides which promotes research on contamination monitoring. Diatom bio-indication tools in rivers have been standardized and normalized (AFNOR NFT 90 354 ; CEN – EN 13946 & EN 14407) and are adapted to assess nutrient and organic matter levels. However these indicators do not assess micropollutants contamination despite diatoms being known to be sensitive to pesticide pollution. The objective of this study is to assess whether bio-indicators based on diatom communities could be developed to assess the impact of pesticide contamination, especially herbicides, on freshwater ecosystems quality. The hypothesis that increasing herbicide concentration reduces diatom diversity wastested on a diatom data set from the French Water Framework Directive monitoring network. The data set includes more than 2000 samples from 14 ecoregions from eastern France over the period 2000 - 2008. To each sample corresponds a list of diatom taxa and 531micropollutants (herbicides, insecticides, fungicides, heavy metals and organic micropollutants) concentration measurements. Diatom diversity was calculated by means of2 classic indices: Shannon's H' (Shannon, 1948) and Simpson's D (Simpson, 1949) and 3taxonomic distinctness indices: ?, ?* and ?+ (Clarke and Warwick, 1998). This poster describes preliminary results which may lead to new bio-indication metrics adapted to pesticide contamination.

International audience ; The increasing contamination by micropollutants in freshwater systems has become a major problem in modern societies, giving rise to toxicological, sanitary and economical concerns. In 2010 the French government adopted a plan for a 50% reduction over 10 years in the use of pesticides which promotes research on contamination monitoring. Diatom bio-indication tools in rivers have been standardized and normalized (AFNOR NFT 90 354 ; CEN – EN 13946 & EN 14407) and are adapted to assess nutrient and organic matter levels. However these indicators do not assess micropollutants contamination despite diatoms being known to be sensitive to pesticide pollution. The objective of this study is to assess whether bio-indicators based on diatom communities could be developed to assess the impact of pesticide contamination, especially herbicides, on freshwater ecosystems quality. The hypothesis that increasing herbicide concentration reduces diatom diversity wastested on a diatom data set from the French Water Framework Directive monitoring network. The data set includes more than 2000 samples from 14 ecoregions from eastern France over the period 2000 - 2008. To each sample corresponds a list of diatom taxa and 531micropollutants (herbicides, insecticides, fungicides, heavy metals and organic micropollutants) concentration measurements. Diatom diversity was calculated by means of2 classic indices: Shannon's H' (Shannon, 1948) and Simpson's D (Simpson, 1949) and 3taxonomic distinctness indices: ?, ?* and ?+ (Clarke and Warwick, 1998). This poster describes preliminary results which may lead to new bio-indication metrics adapted to pesticide contamination.

The increasing contamination by micropollutants in freshwater systems has become a major problem in modern societies, giving rise to toxicological, sanitary and economical concerns. In 2010 the French government adopted a plan for a 50% reduction over 10 years in the use of pesticides which promotes research on contamination monitoring. Diatom bio-indication tools in rivers have been standardized and normalized (AFNOR NFT 90 354 ; CEN – EN 13946 & EN 14407) and are adapted to assess nutrient and organic matter levels. However these indicators do not assess micropollutants contamination despite diatoms being known to be sensitive to pesticide pollution. The objective of this study is to assess whether bio-indicators based on diatom communities could be developed to assess the impact of pesticide contamination, especially herbicides, on freshwater ecosystems quality. The hypothesis that increasing herbicide concentration reduces diatom diversity wastested on a diatom data set from the French Water Framework Directive monitoring network. The data set includes more than 2000 samples from 14 ecoregions from eastern France over the period 2000 - 2008. To each sample corresponds a list of diatom taxa and 531micropollutants (herbicides, insecticides, fungicides, heavy metals and organic micropollutants) concentration measurements. Diatom diversity was calculated by means of2 classic indices: Shannon's H' (Shannon, 1948) and Simpson's D (Simpson, 1949) and 3taxonomic distinctness indices: ?, ?* and ?+ (Clarke and Warwick, 1998). This poster describes preliminary results which may lead to new bio-indication metrics adapted to pesticide contamination.

Biomonitoring is central to the European Union's Water Framework Directive (WFD) and to the French water and aquatic environmental law, but most diatom indices do not separate different anthropogenic impacts. To address this gap, the effect of water chemistry on diatom ecological guilds and life forms was assessed in order to indicate stream perturbations. Generalised additive models (GAMs) were built on a large-scale data set of 1571 samples from the French monitoring network. The relationships between diatom ecological guild and life form metrics were investigated by Principal components analysis and the results predicted by GAMs. The models characterised eight chemical parameters that modified adaptive strategies (ecological guilds) and growth morphology (life forms). Total phosphorus, conductivity, nitrate and pH are the main influencing factors, followed by temperature, dissolved oxygen and organic matter. The findings confirm three groups of diatoms with different adaptive strategies: 1 - fast moving species, 2 - species growing close to the substrate and 3 - species extending to the surface layers of the biofilm. Thirteen diatom metrics displayed a variety of responses to different ranges of the eight chemical parameters. These metrics could be used to help to identify and quantify which chemical alterations are caused by polluted effluents in rivers.

Biomonitoring is central to the European Union's Water Framework Directive (WFD) and to the French water and aquatic environmental law, but most diatom indices do not separate different anthropogenic impacts. To address this gap, the effect of water chemistry on diatom ecological guilds and life forms was assessed in order to indicate stream perturbations. Generalised additive models (GAMs) were built on a large-scale data set of 1571 samples from the French monitoring network. The relationships between diatom ecological guild and life form metrics were investigated by Principal components analysis and the results predicted by GAMs. The models characterised eight chemical parameters that modified adaptive strategies (ecological guilds) and growth morphology (life forms). Total phosphorus, conductivity, nitrate and pH are the main influencing factors, followed by temperature, dissolved oxygen and organic matter. The findings confirm three groups of diatoms with different adaptive strategies: 1 - fast moving species, 2 - species growing close to the substrate and 3 - species extending to the surface layers of the biofilm. Thirteen diatom metrics displayed a variety of responses to different ranges of the eight chemical parameters. These metrics could be used to help to identify and quantify which chemical alterations are caused by polluted effluents in rivers.

Biomonitoring is central to the European Union's Water Framework Directive (WFD) and to the French water and aquatic environmental law, but most diatom indices do not separate different anthropogenic impacts. To address this gap, the effect of water chemistry on diatom ecological guilds and life forms was assessed in order to indicate stream perturbations. Generalised additive models (GAMs) were built on a large-scale data set of 1571 samples from the French monitoring network. The relationships between diatom ecological guild and life form metrics were investigated by Principal components analysis and the results predicted by GAMs. The models characterised eight chemical parameters that modified adaptive strategies (ecological guilds) and growth morphology (life forms). Total phosphorus, conductivity, nitrate and pH are the main influencing factors, followed by temperature, dissolved oxygen and organic matter. The findings confirm three groups of diatoms with different adaptive strategies: 1 - fast moving species, 2 - species growing close to the substrate and 3 - species extending to the surface layers of the biofilm. Thirteen diatom metrics displayed a variety of responses to different ranges of the eight chemical parameters. These metrics could be used to help to identify and quantify which chemical alterations are caused by polluted effluents in rivers.

Biomonitoring is central to the European Union's Water Framework Directive (WFD) and to the French water and aquatic environmental law, but most diatom indices do not separate different anthropogenic impacts. To address this gap, the effect of water chemistry on diatom ecological guilds and life forms was assessed in order to indicate stream perturbations. Generalised additive models (GAMs) were built on a large-scale data set of 1571 samples from the French monitoring network. The relationships between diatom ecological guild and life form metrics were investigated by Principal components analysis and the results predicted by GAMs. The models characterised eight chemical parameters that modified adaptive strategies (ecological guilds) and growth morphology (life forms). Total phosphorus, conductivity, nitrate and pH are the main influencing factors, followed by temperature, dissolved oxygen and organic matter. The findings confirm three groups of diatoms with different adaptive strategies: 1 - fast moving species, 2 - species growing close to the substrate and 3 - species extending to the surface layers of the biofilm. Thirteen diatom metrics displayed a variety of responses to different ranges of the eight chemical parameters. These metrics could be used to help to identify and quantify which chemical alterations are caused by polluted effluents in rivers.

Biomonitoring is central to the European Union's Water Framework Directive (WFD) and to the French water and aquatic environmental law, but most diatom indices do not separate different anthropogenic impacts. To address this gap, the effect of water chemistry on diatom ecological guilds and life forms was assessed in order to indicate stream perturbations. Generalised additive models (GAMs) were built on a large-scale data set of 1571 samples from the French monitoring network. The relationships between diatom ecological guild and life form metrics were investigated by Principal components analysis and the results predicted by GAMs. The models characterised eight chemical parameters that modified adaptive strategies (ecological guilds) and growth morphology (life forms). Total phosphorus, conductivity, nitrate and pH are the main influencing factors, followed by temperature, dissolved oxygen and organic matter. The findings confirm three groups of diatoms with different adaptive strategies: 1 - fast moving species, 2 - species growing close to the substrate and 3 - species extending to the surface layers of the biofilm. Thirteen diatom metrics displayed a variety of responses to different ranges of the eight chemical parameters. These metrics could be used to help to identify and quantify which chemical alterations are caused by polluted effluents in rivers.

P. 141-160 ; In 2000 the European Parliament and The European Union Council recommended that member countries assess water quality using diatoms, as part of the phytobenthos. In Italy this recommendation has given new ímpetus to the study of diatom communities and the application of biotic indices. During the summer of 2004, a total of 11 rivers of the Trentino province (Northern Italy) were sampled, revealing the presence in low abundances of the diatom Didymosphenia geminata {Lyngbye) M. Schmidt. The sites where this diatom occurred were characterised by a low pollution impact; they were also lake fed or had a regulated flow regime, although with different geologies. Morphological features of D. gemina/a frustules were analysed using LM and SEM and specimens could be referred to the morphotype "geminata". In many countries this species is expanding its distribution and in New Zealand it is considered an invasive alga. This work provides an initial report on the presence of D. geminara in the Trento province, and contributes to increasing the knowledge on its distribution in Ilaly and its ecology in the Alps ; SI

Intermittent rivers and ephemeral streams (IRES) are dynamic ecosystems that shift between aquatic and terrestrial states. IRES are widespread, abundant and increasing in extent, but developing biomonitoring programmes to determine their ecological quality is challenging. To date, quality assessments have focused on the aquatic organisms present during wet phases, whereas dry-phase communities remain poorly characterized. We examined multiple biotic groups present in dry IRES channels, to compare assemblages at sites impacted and unimpacted by human activity and to evaluate the potential of each group as an ecological quality indicator. We explored existing, unpublished data for three biotic groups: an aquatic microflora (diatoms), an aquatic fauna (the invertebrate 'seedbank'), and a mixed flora (aquatic and terrestrial plants); notably, we did not source data for terrestrial assemblages with high potential to act as indicators. Diatom and plant assemblage composition differed between impacted and unimpacted sites, and the latter assemblages were more diverse and included more indicator taxa. Invertebrate seedbank taxa richness was higher at unimpacted sites but compositional differences were not detected, probably due to the coarse taxonomic resolution to which abundant taxa were identified. Performance of standard indices of ecological quality was variable, but differences were identified between impacted and unimpacted conditions for all biotic groups. Our results can inform the enhancement of biomonitoring programmes designed to characterize IRES ecological quality in relation to legislative targets. We highlight the need to integrate wet- and dry-phase survey data in holistic quality assessments. Although we suggest diatoms, aquatic plants and the aquatic invertebrate seedbank as having the potential to inform assessment of dry-phase ecological quality, we highlight the need for research to further characterize these aquatic groups and, crucially, to explore terrestrial assemblages with high potential to act as dry-phase quality indicators. ; ISSN:1470-160X ; ISSN:1872-7034

Climatic extreme events such as droughts (unpredictable), dry periods (predictable) or even flush floods, threaten freshwater ecosystemsworldwide. The filtering mechanisms of these events and their strength on communities, however, can be different among regions. While time-for-adaptation theory defines whether or not water scarcity can be considered as disturbance, the stress-dominance theory predicts an increase in importance of environmental filtering and a decrease in the role of biotic interactions in communities with increasing environmental stress. Here, we testedwhether environmental filtering (leading to trait convergence) or limiting similarity (leading to trait divergence) is the main assembly rule shaping the structure and trait composition of benthic diatom assemblages in Mediterranean (Portuguese) and continental (Hungarian) temporary and perennial streams.We assumed that the trait composition of diatomassemblages in the two stream typeswould be less different in the Mediterranean than in the continental region (addressed to time-for-adaptation theory). We also hypothesized that trait composition would be shaped by environmental filtering in the Hungarian streams while by biotic interactions in Portuguese streams (addressed to stress-dominance theory). Our results supported our first hypothesis since traits, which associated primarily to temporary streams were found only in the continental region. Our findings, however, only partially proved the stress-dominance hypothesis. In the continental region,where drying up of streamswere induced by unpredictable droughts, biotic interactionswere the main assembly rules shaping community structure. In contrast, environmental filtering was nearly as important as limiting similarity in structuring trait composition in the Mediterranean region during the predictable dry phasewith no superficial flow. These analyses also highlighted that drought events (both predictable and unpredictable ones) have a complex and strong influence on benthic diatom assemblages resulting even in irreversible changes in trait composition and thereby in ecosystem functioning. ; This paper supported from COST Action CA15113 (SMIRES, Science and Management of Intermittent rivers and Ephemeral streams; www. smires.eu) supported by COST (European Cooperation in Science and Technology) and by the Portuguese Foundation for Science and Technology (FCT) project UIDB/04683/2020 - ICT (Institute of Earth Sciences) and by the European Union through the European Regional Development Fund, included in the COMPETE 2020 (Operational Program Competitiveness and Internationalization) through the ALOP (ALT20-03-0145- FEDER-000004) project. Authors are financially supported by the GINOP 2.3.2-15-2016-00019 project and by NKFIH FK 132 142, FK 131 917 and K 132 150 grants. MHN was supported by Fundação para a Ciência e a Tecnologia – Portugal (PhD grant SFRH/BD/21625/2005), by the Fonds National de la Recherche du Luxembourg (grant AFR, PHD-09-120) and by the Public Research Centre - Gabriel Lippmann (Luxembourg).