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.

International audience ; 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 ...

International audience ; 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 ...

Aquatic biomonitoring has become an essential task in Europe and many other regions as a consequence of strong anthropogenic pressures affecting the health of lakes, rivers, oceans and groundwater. A typical assessment of the environmental quality status, such as it is required by European but also North American and other legislation, relies on matching the composition of assemblages of organisms identified using morphological criteria present in aquatic ecosystems to those expected in the absence of anthropogenic pressures. Through decade-long and difficult intercalibration exercises among networks of regulators and scientists in European countries, a pragmatic biomonitoring approach was developed and adopted, which now produces invaluable information. Nonetheless, this approach is based on several hundred different protocols, making it susceptible to issues with comparability, scale and resolution. Furthermore, data acquisition is often slow due to a lack of taxonomic experts for many taxa and regions and time-consuming morphological identification of organisms. High-throughput genetic screening methods such as (e)DNA metabarcoding have been proposed as a possible solution to these shortcomings. Such "next-generation biomonitoring", also termed "biomonitoring 2.0", has many advantages over the traditional approach in terms of speed, comparability and costs. It also creates the potential to include new bioindicators and thereby further improves the assessment of aquatic ecosystem health. However, several major conceptual and technological challenges still hinder its implementation into legal and regulatory frameworks. Academic scientists sometimes tend to overlook legal or socioeconomic constraints, which regulators have to consider on a regular basis. Moreover, quantification of species abundance or biomass remains a significant bottleneck to releasing the full potential of these approaches. Here, we highlight the main challenges for next-generation aquatic biomonitoring and outline principles and good ...