Short-term effects of macrophyte removal on aquatic biodiversity in rivers and lakes

Mass development of macrophytes is an increasing problem in many aquatic systems worldwide. Dense mats of macrophytes can negatively affect activities like boating, fishing or hydropower production and one of the management measures often applied is mechanical removal. In this study, we analyzed the effect of mechanical macrophyte removal on phytoplankton, zooplankton, and macroinvertebrate (pelagic and benthic samples) assemblages. Our study covered five sites in four countries in Europe and Africa with highly variable characteristics. In all sites, dense mats of different macrophyte species (Juncus bulbosus in a river in Norway; a mix of native macrophytes in a German river, Elodea nuttallii in a lake in Germany, Ludwigia spp. In a French lake and Pontederia crassipes in a South African lake) are problematic and mechanical removal was applied. In every country, we repeated the same BACI (Before-After-Control-Impact) design, including “before”, “one week after”, and “six weeks after” sampling in a control and an impact section. Repeating the same experimental design at all sites allowed us to disentangle common effects across all sites from site-specific effects. For each taxonomic group, we analyzed three structural and three functional parameters, which we combined in a scoring system. Overall, the removal of macrophytes negatively affected biodiversity, in particular of zooplankton and macroinvertebrate assemblages. In contrast, plant removal had positive effects on the phytoplankton assemblages. Effects were more pronounced one week after removal than six weeks after. Consequently, we suggest a stronger consideration of the effect of plant removal on biodiversity to arrive at more sustainable management practices in the future.acceptedVersio

Effects of large dams on the aquatic food web along a coastal stream with high sediment loads

The contribution of two basal energy sources – detrital organic matter and primary producers – as part of aquatic food webs varies typically along river continua. A host of barriers to river flow increase the water residence time and sediment and nutrient retention in reservoirs worldwide, and potentially alter the balance between detritus-based and algae-based energy pathways in the downstream food webs. We explored this issue on the Sélune River (Normandy, France), a small coastal stream that drains an agricultural catchment with high sediment runoff. Seasonal measurements of the following parameters were compared upstream and downstream of the reservoirs of two large dams (16 m and 36 m high): sediment fluxes, nutrient and chlorophyll a concentrations, algal communities in the epilithic biofilm (taxonomic composition, biomass and growth), and benthic invertebrate communities (abundance and trophic guild structure). As anticipated, annual sediment fluxes were much lower downstream of the reservoirs, where significant decreases in water turbidity, phosphate and silicate concentrations were recorded. A higher chlorophyll a concentration in water and a higher contribution of pelagic algae taxa to the photosynthetic biofilm suggested drifting and deposition of reservoir-borne phytoplankton downriver. Photosynthetic biofilm growth was higher downstream of the reservoirs in spring and fall, and so was the abundance of herbivores in the invertebrate community, notably scrapers and algae eaters. Energy pathways within riverine food webs were traced using stable isotope analyses of carbon (C) and nitrogen in the tissues of aquatic consumers (invertebrates and fish). Mixing models revealed a discontinuity in the origin of the C entering the food webs along the river continuum, confirming a greater contribution of algal C to aquatic consumers downstream of the reservoirs. These results illustrate mechanisms whereby large reservoirs can modulate C flow in food webs along a small coastal river with high sediment loads, and make it possible to anticipate the effects of dam removal on the future river ecosystem

Energy input and dissipation in a temperate lake during the spring transition

ADCP and temperature chain measurements have been used to estimate the rate of energy input by wind stress to the water surface in the south basin of Windermere. The energy input from the atmosphere was found to increase markedly as the lake stratified in spring. The efficiency of energy transfer (Eff), defined as the ratio of the rate of working in near-surface waters (RW) to that above the lake surface (P10), increased from ∼0.0013 in vertically homogenous conditions to ∼0.0064 in the first 40 days of the stratified regime. A maximum value of Eff∼0.01 was observed when, with increasing stratification, the first mode internal seiche period decreased to match the diurnal wind period of 24 h. The increase in energy input, following the onset of stratification was reflected in enhancement of the mean depth-varying kinetic energy without a corresponding increase in wind forcing. Parallel estimates of energy dissipation in the bottom boundary layer, based on determination of the structure function show that it accounts for ∼15% of RW in stratified conditions. The evolution of stratification in the lake conforms to a heating stirring model which indicates that mixing accounts for ∼21% of RW. Taken together, these estimates of key energetic parameters point the way to the development of full energy budgets for lakes and shallow seas

Tools for crushing diatoms – opal teeth in copepods feature a rubber-like bearing composed of resilin

Diatoms are generally known for superior mechanical properties of their mineralised shells. Nevertheless, many copepod crustaceans are able to crush such shells using their mandibles. This ability very likely requires feeding tools with specific material compositions and properties. For mandibles of several copepod species silica-containing parts called opal teeth have been described. The present study reveals the existence of complex composite structures, which contain, in addition to silica, the soft and elastic protein resilin and form opal teeth with a rubber-like bearing in the mandibles of the copepod Centropages hamatus. These composite structures likely increase the efficiency of the opal teeth while simultaneously reducing the risk of mechanical damage. They are supposed to have coevolved with the diatom shells in the evolutionary arms race, and their development might have been the basis for the dominance of the copepods within today's marine zooplankton

Exploration de l’expérience vécue et de la mise en sens des enjeux éthiques et psychosociaux lies aux innovations technologiques et thérapeutiques en oncogénétique : une approche critique

Genetic testing for cancer, which aims to identify hereditary predispositions to cancer, is a dynamic medical field, where many technological and therapeutic innovations emerge. Scientific progress allows genetic testing to be both less expensive, faster and more efficient, which paradoxically raises new ethical and psychosocial issues, such as the patient’s ability to give informedconsent, or the risk of misuses of genetic testing. These changes led us to explore how lived experience is mobilized in the process of making sense of the ethical and psychosocial issues related to innovations in the field of genetic testing of cancer. This research, anchored in social psychology, is based on a critical approach of health issues, which questions the needs, expectations and constraints of health professionals and patients, and the power relationships that take place both at the interindividual level and, on a larger scale, within health policies. Based on the theoretical notion of lived experience, we aimed to understand how individuals make sense of their world, and more particularly of innovations in the field of genetic testing. Lived experience, necessarily social and socially constructed, has many dimensions, among which we chose to investigate the following three: - A practical dimension, based on the study of doctor patient-relationship, - A knowledge dimension, investigated through the negotiation of expert knowledge and common sense thanks to the social representations theory, - And an emotional dimension, based on the study of the phenomena of emotion regulation and social sharing of emotions.Based on the principles of methodological and data triangulation, our exploration was based on two complementary qualitative studies. The first study aimed to investigate sense making processes related to professional activities and how health professionals working in genetic testing for cancer imagine their future and the future of genetic testing. We led 27 semi-structured interviews with genetic counsellors and clinical geneticists. An Interpretative Phenomenological Analysis (IPA) was performed analyze the data gathered, with the assistance of N-Vivo software. The second study aimed to explore the co-construction of representations related to new uses to genetic testing of cancer, and to investigate the impact of lived experience on the understanding of ethical issues related to genetic testing. We led ten focus groups, based mostly on the resolution of ethical dilemmas, with 18 women who attended at least one genetic counselling consultation, and 21 women who did not have a similar experience. All women were recruited thanks to the online collaborative research platform “Les Seintinelles”, which constitutes a cancer related community of interest.This research allowed us to highlight the social nature of genetic testing of cancer. This medical field is defined by two main goals: allowing carriers of genetic predisposition to undergo preventive measures, and making sense of a family history of cancer. Genetic counselling professionals report a high level of personal involvement in their work and emotion regulation strategies acquired on purpose and based on a strict division between their personal and professional life. The acknowledgement oftheir professional skills and the perceived quality of their relationships with their patients contribute highly to the work-related satisfaction of genetic testing professionals. The doctor-patient relationship is structured by an ideal of non-directivity, which can be questioned by the need to accompany and protect the patients, who are considered as vulnerable. Because of the risks of misuses of genetic testing, the strict legislation related to these practices in France is most often considered as valuable.Clinical geneticists and genetic counsellors are considered the most likely to provide genetic testing within an ethical framework.L'oncogénétique, l'étude des prédispositions héréditaires au cancer, constitue une discipline médicale dynamique, faisant l'objet de nombreuses innovations, tant technologiques que thérapeutiques. Les progrès scientifiques en oncogénétique rendent le recours aux tests génétiques à la fois moins coûteux, plus rapide et plus efficace, ce qui soulève ou réactualise paradoxalement de nombreux enjeux éthiques et psychosociaux tels que la capacité des patients à formuler un consentement éclairé ou le risque de dérives liées à des mésusages des tests génétiques. Face à ces changements, nous avons choisi d’explorer la façon dont est mobilisée l'expérience vécue ou projetée dans la mise en sens des enjeux éthiques et psychosociaux liés aux innovations technologiques et thérapeutiques en oncogénétique. Ce travail de recherche, résolument ancré en psychologie sociale, s'inscrit dans une approche critique des questions de santé où sont interrogés à la fois les besoins, attentes et contraintes des professionnels et usagers du système de soins, et les relations de pouvoir qui s'exercent tant au niveau interindividuel qu'au niveau plus large des politiques de santé. C'est grâce à la notion d'expérience vécue ou projetée que nous avons cherché à comprendre la façon dont les individus font sens de leur monde, et plus particulièrement des évolutions qui touchent l'oncogénétique. L'expérience, nécessairement sociale et socialement construite, est multidimensionnelle, nous proposons d'investiguer plus particulièrement trois de ces dimensions : - une dimension pratique centrée sur l’étude des relations soignants-patients, - une dimension de connaissances étudiée au travers de la négociation des connaissancesexpertes et du savoir de sens commun grâce à la théorie des représentations sociales, - et enfin une dimension émotionnelle envisagée sous l'angle des phénomènes de partage social des émotions et de régulation émotionnelle.Afin de répondre à ces objectifs, deux études complémentaires reposant sur des méthodologies qualitatives ont été mises en place dans une perspective de triangulation des données. La première étude a visé à investiguer la mise en sens des pratiques professionnelles ainsi que la façon dont les soignants se projettent dans un champ disciplinaire en pleine transition et dans leurs pratiques futures. Nous avons mené des entretiens semi-directifs auprès de 27 professionnels en oncogénétique (oncogénéticiens et conseillers en génétique). Les données recueillies ont fait l'objet d'une analyse interprétative phénoménologique (IPA) adaptée à un large échantillon sur les données recueillies, en nous appuyant sur le logiciel d'aide à l'analyse N-Vivo. La seconde étude avait pour objectif d'explorer la co-construction des représentations liées aux nouveaux usages de l'oncogénétique, ainsi que d'étudier l'impact de la l'expérience vécue sur la compréhension des enjeux éthiques liés àl'oncogénétique. Dix focus groups, reposant principalement sur la résolution de dilemmes éthiques, ont été réalisés auprès de 18 femmes ayant l'expérience d'au moins une consultation en oncogénétique et 21 femmes n'ayant pas d'expérience similaire, toutes recrutées par le biais de la plateforme Les Seintinelles, qui constitue une communauté d'intérêt autour du cancer. Une analyse inspirée de l'IPA a été réalisée sur les données ainsi recueillies avec appui sur le logiciel N-Vivo.Notre recherche a permis de souligner le caractère résolument social de la recherche de prédispositions génétiques en oncologie. L’oncogénétique est définie socialement autour de deux de ces objectifs : permettre de mettre en place des mesures de prévention destinées aux individus porteurs d’une mutation génétique, et donner une explication à une histoire familiale de cancer....

Exploration of lived experience and sense-making efforts of ethical and psychosocial stakes related to technological and therapeutic innovations regarding genetic testing for hereditary cancers : a critical approach

L'oncogénétique, l'étude des prédispositions héréditaires au cancer, constitue une discipline médicale dynamique, faisant l'objet de nombreuses innovations, tant technologiques que thérapeutiques. Les progrès scientifiques en oncogénétique rendent le recours aux tests génétiques à la fois moins coûteux, plus rapide et plus efficace, ce qui soulève ou réactualise paradoxalement de nombreux enjeux éthiques et psychosociaux tels que la capacité des patients à formuler un consentement éclairé ou le risque de dérives liées à des mésusages des tests génétiques. Face à ces changements, nous avons choisi d’explorer la façon dont est mobilisée l'expérience vécue ou projetée dans la mise en sens des enjeux éthiques et psychosociaux liés aux innovations technologiques et thérapeutiques en oncogénétique. Ce travail de recherche, résolument ancré en psychologie sociale, s'inscrit dans une approche critique des questions de santé où sont interrogés à la fois les besoins, attentes et contraintes des professionnels et usagers du système de soins, et les relations de pouvoir qui s'exercent tant au niveau interindividuel qu'au niveau plus large des politiques de santé. C'est grâce à la notion d'expérience vécue ou projetée que nous avons cherché à comprendre la façon dont les individus font sens de leur monde, et plus particulièrement des évolutions qui touchent l'oncogénétique. L'expérience, nécessairement sociale et socialement construite, est multidimensionnelle, nous proposons d'investiguer plus particulièrement trois de ces dimensions : - une dimension pratique centrée sur l’étude des relations soignants-patients, - une dimension de connaissances étudiée au travers de la négociation des connaissancesexpertes et du savoir de sens commun grâce à la théorie des représentations sociales, - et enfin une dimension émotionnelle envisagée sous l'angle des phénomènes de partage social des émotions et de régulation émotionnelle.Afin de répondre à ces objectifs, deux études complémentaires reposant sur des méthodologies qualitatives ont été mises en place dans une perspective de triangulation des données. La première étude a visé à investiguer la mise en sens des pratiques professionnelles ainsi que la façon dont les soignants se projettent dans un champ disciplinaire en pleine transition et dans leurs pratiques futures. Nous avons mené des entretiens semi-directifs auprès de 27 professionnels en oncogénétique (oncogénéticiens et conseillers en génétique). Les données recueillies ont fait l'objet d'une analyse interprétative phénoménologique (IPA) adaptée à un large échantillon sur les données recueillies, en nous appuyant sur le logiciel d'aide à l'analyse N-Vivo. La seconde étude avait pour objectif d'explorer la co-construction des représentations liées aux nouveaux usages de l'oncogénétique, ainsi que d'étudier l'impact de la l'expérience vécue sur la compréhension des enjeux éthiques liés àl'oncogénétique. Dix focus groups, reposant principalement sur la résolution de dilemmes éthiques, ont été réalisés auprès de 18 femmes ayant l'expérience d'au moins une consultation en oncogénétique et 21 femmes n'ayant pas d'expérience similaire, toutes recrutées par le biais de la plateforme Les Seintinelles, qui constitue une communauté d'intérêt autour du cancer. Une analyse inspirée de l'IPA a été réalisée sur les données ainsi recueillies avec appui sur le logiciel N-Vivo.Notre recherche a permis de souligner le caractère résolument social de la recherche de prédispositions génétiques en oncologie. L’oncogénétique est définie socialement autour de deux de ces objectifs : permettre de mettre en place des mesures de prévention destinées aux individus porteurs d’une mutation génétique, et donner une explication à une histoire familiale de cancer.....Genetic testing for cancer, which aims to identify hereditary predispositions to cancer, is a dynamic medical field, where many technological and therapeutic innovations emerge. Scientific progress allows genetic testing to be both less expensive, faster and more efficient, which paradoxically raises new ethical and psychosocial issues, such as the patient’s ability to give informedconsent, or the risk of misuses of genetic testing. These changes led us to explore how lived experience is mobilized in the process of making sense of the ethical and psychosocial issues related to innovations in the field of genetic testing of cancer. This research, anchored in social psychology, is based on a critical approach of health issues, which questions the needs, expectations and constraints of health professionals and patients, and the power relationships that take place both at the interindividual level and, on a larger scale, within health policies. Based on the theoretical notion of lived experience, we aimed to understand how individuals make sense of their world, and more particularly of innovations in the field of genetic testing. Lived experience, necessarily social and socially constructed, has many dimensions, among which we chose to investigate the following three: - A practical dimension, based on the study of doctor patient-relationship, - A knowledge dimension, investigated through the negotiation of expert knowledge and common sense thanks to the social representations theory, - And an emotional dimension, based on the study of the phenomena of emotion regulation and social sharing of emotions.Based on the principles of methodological and data triangulation, our exploration was based on two complementary qualitative studies. The first study aimed to investigate sense making processes related to professional activities and how health professionals working in genetic testing for cancer imagine their future and the future of genetic testing. We led 27 semi-structured interviews with genetic counsellors and clinical geneticists. An Interpretative Phenomenological Analysis (IPA) was performed analyze the data gathered, with the assistance of N-Vivo software. The second study aimed to explore the co-construction of representations related to new uses to genetic testing of cancer, and to investigate the impact of lived experience on the understanding of ethical issues related to genetic testing. We led ten focus groups, based mostly on the resolution of ethical dilemmas, with 18 women who attended at least one genetic counselling consultation, and 21 women who did not have a similar experience. All women were recruited thanks to the online collaborative research platform “Les Seintinelles”, which constitutes a cancer related community of interest.This research allowed us to highlight the social nature of genetic testing of cancer. This medical field is defined by two main goals: allowing carriers of genetic predisposition to undergo preventive measures, and making sense of a family history of cancer. Genetic counselling professionals report a high level of personal involvement in their work and emotion regulation strategies acquired on purpose and based on a strict division between their personal and professional life. The acknowledgement oftheir professional skills and the perceived quality of their relationships with their patients contribute highly to the work-related satisfaction of genetic testing professionals. The doctor-patient relationship is structured by an ideal of non-directivity, which can be questioned by the need to accompany and protect the patients, who are considered as vulnerable. Because of the risks of misuses of genetic testing, the strict legislation related to these practices in France is most often considered as valuable.Clinical geneticists and genetic counsellors are considered the most likely to provide genetic testing within an ethical framework

Biogeochemical functioning and sedimentary in response to physical forcing: impact on water quality and dynamics of algal blooms

International audienc

Biogeochemical functioning and sedimentary in response to physical forcing: impact on water quality and dynamics of algal blooms

International audienc

Dynamique du phytoplancton et flux sédimentaires en réponse aux perturbations par le vent et la pluie dans les systèmes lentiques

La dynamique du phytoplancton d'eau douce est contrôlée par le forçage physique, lié aux conditions météorologiques. Or ce forçage varie également à l'échelle journalière. Nous avons émis l'hypothèse que ces perturbations influencent le phytoplancton. Les conséquences possibles de ces perturbations sont la redistribution verticale des populations, un apport de nutriments, une augmentation de la turbulence dans l'épilimnion ou un approfondissement de ce dernier. Ces modifications ont des répercussions sur la prise de sels nutritifs, sur les pertes par sédimentation et sur la disponibilité en lumière pour les communautés de phytoplancton. Les études de terrain et en milieu contrôlé ont mis en évidence une augmentation de la structure de taille, associée à une augmentation des flux sédimentaires, après des perturbations par le vent. Des changements de la communauté ont été observés lors d'apports de nutriments limitants ou de modifications soudaines de l'intensité de stratification.RENNES1-BU Sciences Philo (352382102) / SudocRENNES-Géosciences (352382209) / SudocSudocFranceF