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2021 marks the 100th anniversary of the golden era of what scholars have designated as “Russian Berlin” (Русский Белрин). The phenomenon was by many forgotten, except for the few who remained in the city after 1923; over shadowed by the new emigre centers in Paris, Prague, and later New York; intentionally overlooked and ignored by Soviet literary historians for decades. When I began my study of that time and its writers in 1984 there were few scholars interested in the period, among them Fritz Mierau at the time in East Berlin and the then German Democratic Republic. We relied on writings by Ehrenburg, Shklovski, and the living witnesses, Nina Berberova in Princeton, Alexander Bakhrakh in Paris, Roman Goul in New York. A newly discovered Vera Lourie in Berlin would become for a few years a sought after interviewee by the German press. Gorbachev’s “glasnost” opened doors, accelerated by the fall of the Berlin wall and ultimately the Soviet Union. German scholars, Karl Schlögel and Amory Burchard, the exiled Lew Kopelev, and Russians began to pay attention culminating in a 700 page illustrated Berlin-Moskau /Moskau-Berlin 1900-1950 [1]. But today 100 years later little attention is being devoted to this truly golden era in Russian literature., В 2021 году исполняется 100 лет золотой эры того, что ученые назвали “Русским Берлином.” Много забыто, исчезнувшее с теми, кто остался в городе после 1923 года; и ростом других новых эмигрантских центров в Париже, Праге и Нью-Йорке. Когда я начал свое изучение того времени и его авторов в 1984 году, было мало тех, кто интересовался этим периодом. Одно исключение было Фриц Мирау в то время в Восточном Берлине и Германской Демократической Республике. Мы опирались на сочинения Эренбурга, Шкловского и живых свидетелей, Нины Берберовой в Принстоне, Александра Бахраxа в Париже, Романа Гуля в Нью-Йорке и одной из последних свидетелей в Берлине, Веры Лурье. «Гласность» Горбачева открыла двери, потом падение Берлинской стены и, в конечном итоге, распад Советского Союза. Немецкие ученые Карл Шлегель и Амори Бурхард, изгнанный Лев Копелев, и русские наконец в 90-х годах начали обращать на это внимание. Кульминацией интереса стал 700-страничный иллюстрированный том Берлин-Москва / Москва-Берлин 1900-1950 гг.

Iakov Golosovker developed the theme of the mythologization of autobiography in a manner that was close to the Russian Symbolists (see his My Life Myth). The proof of this is in his unpublished letter to Andrei Bely, which can be dated to 1921, the time when they were both members of the Moscow ‘Vol'fila’. It is possible that their meetings and creative ties in the late 1920s resulted in the image of Christ visiting a modern town in Bely’s Petersburg and Golosovker’s Burned novel.

This paper deals critically with the posthumous interpretation of Foucault's work by Gilles Deleuze. The inquiry begins with Deleuze's claim that the late Foucault was a topologist like Andrei Bely in his modernist novel 'Petersburg'. In order to illuminate this Deleuzian perspective, the author discusses the concepts of dispositif and chronotope. By analyzing a key scene from 'Petersburg', the paper concludes that Deleuze's notion of topology is closer to his own philosophical system than to Foucault's historical research.

Fluoxetine is a widely used antidepressant, frequently found in aquatic ecosystems. We investigated its effects on two freshwater prosobranch gastropods: Valvata piscinalis (European valve snail) and Potamopyrgus antipodarum (New Zealand mudsnail), which have different reproductive modes. The fecundity of V. piscinalis (cumulate number of eggs at day 42) was not affected with an NOEC of 100 mvg/L nominal concentration (69 microg/L measured concentration). The mudsnail P. antipodarum responded in a biphasic dose-effect curve at low concentrations. The cumulate number of neonates at day 42 had an LOEC of 100 microg/L (69 microg/L) and an NOEC of 33.3 microg/L (13 microg/L), whereas the embryos in the brood pouch at day 42 only showed an LOEC of 3.7 microg/L (1 microg/L). We also observed histological effects in P. antipodarum (gonadal thickness). Among the sexual steroids we measured only testosterone which varied, independent of reproduction. Moreover the use of two closely related species highlights the interspecific variability.

International audience; Inundation marks the shift from a terrestrial ecosystem to an aquatic ecosystem in ephemeral rivers. The forms and rates of responses by aquatic invertebrates and sediment microbes to inundation depend on desiccation resistance during preceding dry periods.As desiccation resistance is likely to vary with dry period duration, we assessed invertebrate and microbial responses to variable lengths of inundation in sediments from an ephemeral reach of the Selwyn River, New Zealand. Microbial response variables were dissolved oxygen consumption and non-specific esterase activity. Sampling sites along the reach had been continuously dry for 1592 d prior to sample collection. The onset of flow simulated by a 17-d experimental inundation led to the appearance of aquatic invertebrates in all samples, but the assemblages varied with the length of the preceding dry period. Taxon richness decreased linearly with dry period length while density decreased exponentially. These patterns indicate that a large number of individuals from desiccation-sensitive taxa were eliminated soon after flow ceased, and a low-density assemblage composed of a small number of desiccation-resistant taxa persisted during prolonged dry periods. As with invertebrate density, sediment respiration and non-specific esterase activity decreased with length of dry period, and were characterized by exponential decay functions. The results of the inundation experiments suggest that a temporal ecotone exists for about one week after the disappearance of flowing water, and before the terrestrial system stabilizes.

International audience; Detection and assessment of the impact of pollution on biological resources imply increasing research on early-warning markers such as metallothioneins in metal exposure. Metallothioneins are cytosolic, low-molecular-weight proteins, involved principally in essential metal homeostasis and non-essential metal detoxication. Metallothionein synthesis could be influenced by abiotic (season) or biotic (reproduction process) factors directly or indirectly by its effect on metal bio-accumulation (i.e., sex, weight). In view of using metallothioneins as metal-exposure biomarkers in Gammarus pulex, this study attempts to define the effect of several factors (sex, weight/size and season) on the level of this protein. Metallothionein levels recorded in individuals over a large range of weights indicate a negative correlation between them. Inversely in our conditions, no difference was observed between male and female organisms. During field study, metallothionein level changes were observed with the highest levels in autumn and winter periods. The highest metallothionein levels were observed after the reproduction period, perhaps with the metabolic needs of biologically available essential metal such as zinc.

International audience; Bioassays can be used in aquatic toxicology to provide individual determinations, however ecotoxicology is now attempting to assess the impact of pollution on populations. The main issue is how to infer the impact on an entire population of the toxic effects observed in individuals. At the individual level, Dynamic Energy Budget in Toxicology (DEBtox) theory provides a set of mechanistic models of survival, reproduction and growth continuously as a function of time and exposure concentration, in which the parameters used have clear biological meanings. These models have been designed for the analysis of data provided by the internationally standardized toxicity tests, and sometimes make it clear which is the mode of action of the contaminant. Matrix population models directly yield the population growth rate, the most robust endpoint in risk assessment at the population level. By combining DEBtox theory and matrix population models, we extrapolate every effects of the toxic compound on the individual (reduced fecundity, growth and survival) to the population level. Both lethal and sublethal effects are integrated into a single parameter, the population growth rate, which is calculated continuously against exposure concentration. We can thus compare the consequences at the population level of choosing one or another assumption about the mode of action of the contaminant at the individual level. We used various complementary matrix population models, in order to perform a complete sensitivity analysis, highlighting critical demographic parameters in the evolution of population growth rate as a function of contaminant concentration. Here, we apply this method to a test organism commonly used in ecotoxicology, Daphnia magna, through a case study of cadmium contamination.

International audience; 1. Many aspects of the flow regime influence the structure of stream communities, among which the minimum discharge left in rivers has received particular attention. However,instream habitat models predicting the ecological impacts of discharge management often lack biological validation and spatial generality, particularly for large rivers with many fish species. 2. The minimum flow at Pierre-Be´nite, a reach of the Rhone river bypassed by artificial channels, was increased from 10 to 100 m3 s)1 in August 2000 (natural mean discharge 1030 m3 s)1), resulting in a fivefold increase in average velocity at minimum flow. Fish were electrofished in several habitat units on 12 surveys between 1995 and 2004. 3. Principal components analysis revealed a significant change in the relative abundance of fish species. The relative abundance of species preferring fast-flowing and/or deep microhabitats increased from two- to fourfold after minimum flow increase. A change in community structure confirmed independent quantitative predictions of an instream habitat model. This change was significantly linked to minimum flow increase, but not to any other environmental variables describing high flows or temperature at key periods of fish life cycle. The rapidity of the fish response compared with the lifespan of individual species can be explained by a differential response of specific size classes. 4. The fish community at Pierre-Be´nite is in a transitional stage and only continued monitoring will indicate if the observed shift in community structure is perennial. We expect that our case study will be compared with other predictive tests of the impacts of flow restoration in large rivers, in the Rhone catchment and elsewhere.; Cinq ans après augmentation du débit minimum à Pierre-Bénite, tronçon court-circuité du Rhône Français, les espèces d'eau courante ont doublé en proportion. Ce changement valide des prédictions quantitatives des modèles d'habitat réalisées avant restauration du débit. Il s'agit d'une première validation de prédictions concernant les communautés de poissons.

In the boreal forest, watershed logging may increase runoff as well as chemical loading, including nutrient, dissolved organic carbon and mercury, to lakes. Since they are exposed directly to nutrients and contaminants exported from the watershed, littoral communities such as periphyton may respond quickly to watershed disturbances. The objectives of this study were to evaluate the response of periphyton to watershed logging using a BACI (Before/After Control, Impact) statistical approach, and to develop a predictive tool to facilitate the elaboration of practical logging policies aimed at reducing Hg loading to lakes. In this study, we compare the periphyton biomass as well as their total mercury and methyl-mercury levels in 18 boreal Canadian shield lakes. During the ice-free season from 2000 to 2002, eight lakes were monitored before and after logging whereas the others served as controls. The BACI statistical analyses reveal a significant impact of logging on periphyton biomass (decrease; 0.6 to 1.5-fold) and methyl-mercury accumulation (increase; 2 to 9.6-fold). This study demonstrates that periphyton responds quickly to disturbances of the watershed. Our results suggest that the periphyton and watershed characteristics could serve as good management tools and logging should be limited in watersheds with a mean slope below 7.0%.; En forêt boréale, la coupe forestière peut augmenter l'écoulement et l'apport d'éléments chimiques aux lacs tel que le carbone organique dissous et le mercure. Les communautés littorales, comme le périphyton, peuvent être exposées directement aux apports de contaminants exportés du bassin versant, et ainsi répondre rapidement aux perturbations de ce dernier. Les objectifs de cette étude étaient d'évaluer la réponse du biofilm périphytique aux coupes forestières en utilisant une approche statistique de type BACI, et de développer des outils prédictifs utiles pour l'élaboration de politiques forestières visant la réduction des apports de Hg dans les lacs. Dans cette étude, nous avons échantillonné 18 lacs boréaux du bouclier canadien et comparé la biomasse et les concentrations de mercure total et méthyl-mercure du périphyton. Durant la saison libre de glace de 2000 à 2002, huit lacs ont été échantillonnés avant et après la coupe alors que les autres ont servi de témoins. Les analyses statistiques BACI révèlent un impact significatif des coupes sur la biomasse (diminution; 0.6 à 1.5 fois) et sur les concentrations de méthyl-mercure (augmentation; 2 à 9.6 fois). Cette étude démontre que le périphyton répond rapidement à une perturbation du bassin versant. Nos résultats suggèrent que le périphyton et les caractéristiques du bassin versant peuvent être de bons outils de gestion et que la coupe forestière devrait être limitée lorsque la pente moyenne est inférieure à 7.0%.

We show that, when performing water-only tests in semi-static conditions with the amphipod Hyalella azteca, it is necessary to use sieves prepared as described in this paper. Feeding condition 0.1 mg/individual/working day appeared to be relevant to ensure optimal growth and reproduction. Finally, it seems that sediments do not provide extra benefit compared to prepared sieves, provided there is sufficient cover and some bacterial development.

We investigated the relationships between different environmental variables and the spatial distribution patterns of the stoneloach (Barbatula barbatula) at the stream system, the stream site, and the mesohabitat (riffle/pool) scales in south-western France. Stoneloach occurred at 240 sites (out of 554 sampling sites), chiefly close to the source, in areas at low elevation and with weak slopes. Population density at a site was primarily influenced by physical conditions. Stream width was positively related to the probability of presence of stoneloach within the stream system, but negatively related to local density. These results indicate that stoneloaches can occur in a wide range of streams, but they are less abundant in wide rivers, probably because of lower habitat heterogeneity. Slope was negatively correlated to both fish presence at the regional scale and local density, suggesting that stoneloach’s swimming performance were weak under greater erosive forces. These results suggested that the distribution of populations and the density of stoneloach were governed by the suitability of physical habitat. Multi-scale studies of factors influencing a species’ distribution allow to integrate patterns observed at different scales, and enhance our understanding of interactions between animals and their environment. The use of few pertinent variables in successful final models could reduce the effort and cost of data collection for water management applications.

International audience; Despite IFIM worldwide success, some criticisms have not been sufficiently addressed in the literature: lack of sufficient validation of the relationships between potential available habitat and biomass of fish, particularly in warmwater streams; complexity of habitat modelling; too narrow focus on selected fish species habitat instead of entire riverine ecosystem; complexity and expense of implementation. First, we briefly address the general context of ecological flows methods. Second, we present some successful validations of microhabitat applications at the fish population (Brown trout, Salmo trutta, L. 1758) and community levels. Finally, we present the results of the statistical analysis and modelling of about one hundred Phabsim simulations. The functions of habitat (WUA) versus discharge could be predicted by synthetic hydraulic variables, in particular the Froude and Reynolds numbers. A simplified alternative to Phabsim, named Estimhab opens the way to habitat measurements in a great number of sites, particularly useful to view habitat at entire watershed level.

International audience; DEBtox model is a biologically based model used to analyse aquatic toxicity data (Kooijman and Bedaux, 1996). To date, it has not been used to analyse sediment survival tests, mainly because this would require daily counting of survivors, which is difficult for benthic organisms. In the present study, we adapted survival toxicity tests with the midge Chironomus riparius to permit survival data analysis with DEBtox. To validate the adaptation proposed, we exposed organisms to two chemicals, copper and methiocarb. We exposed larvae of second, third and fourth instar to different concentrations of the tested compounds and two different diets to assess the influence of diet and instar on DEBtox parameter estimates. Daily counting of organisms did not affect survival and did not lead to much more effort when compared to usual tests. Moreover, the analysis profited much from use of the DEBtox model. It was possible, with only survival data to estimate and validate the kinetics of the compounds, to predict survival during the recovery of exposed organisms and to assess the influence of food availability on toxicity. Food availability did not influence methiocarb toxicity, but copper was more toxic to food-limited organisms when a threshold concentration was exceeded. Comparison of parameters estimate also helped in understanding the differences in toxicity responses between instars. For the two compounds we studied, the difference was entirely explained by differences in threshold values.; Le modèle DEBtox est un modèle à fondement biologique utilisé pour l'analyse des données de toxicité aquatique (Kooijman et Bedaux, 1996). Jusqu'à présent, il n'a jamais été utilisé pour analyser les données des tests de survie sur sédiment, ce qui est principalement du à la difficulté de suivre la survie des organismes benthiques jour après jour. Ici, nous avons adapté les tests de survie avec Chironomus riparius pour permettre l'analyse des données avec DEBTox. Pour valider notre approche, nous avons exposé les organismes à deux contaminants, le cuivre et le mercaptodiméthur (un pesticide). Trois stades larvaires différents (deuxième, troisième et quatrième) et deux régimes alimentaires (ad libitum et limitant) ont été considérés. Le décompte quotidien des survivants n'a pas altéré la bonne marche du test et n'a pas donné lieu à beaucoup plus d'effort qu'un test classique. De plus, nous avons pu tirer des bénéfices de l'utilisation de DEBtox. Il a ainsi été possible, à partir uniquement des données de survie, d'estimer la cinétique des composés, de prédire la survie au cours de la phase de dépuration, et de caractériser l'influence de la nourriture. Le manque de nourriture n'influe pas sur la toxicité du pesticide mais augmente celle du cuivre. Quant à la différence entre stades, elle s'est caractérisée uniquement par une différence entre les concentrations seuils d'effet.

Corbicula fluminea populations were sampled annually from 1997 to 2000 at the beginning of the autumn, i.e. at the end of the reproduction period, at 14 sites along the Saône and Rhône rivers. Recruitement in the upper reach of these rivers was generally high. Conversely, the observation of other sectors revealed generally low or no production of juveniles, missing cohorts and major year to year variations in population structure. Nevertheless, no dramatic fall in population density was observed during the surveyed four years. This suggests that the longevity of the Corbicula populations of the Saône and Rhône rivers is ensured to a great extent by the drifting of individuals from the upper course of these rivers and their tributaries. Two possible causes are put forward to explain the low recruitment observed: low production of phytoplankton that prevents adults from development of phytoplankton and it is lethal for pediveligers., Les populations de Corbicula fluminea ont été échantillonnées annuellement en début d'automne, c'est-à-dire en fin de période de reproduction, de 1997 à 2000 sur 14 sites jalonnant la Saône et le Rhône. Dans le cours supérieur de ces cours d'eau, le recrutement est généralement important. En revanche, dans les autres secteurs on observe une production de juvéniles généralement faible ou nulle, des cohortes manquantes et d'importantes variations de la structure des populations d'une année sur l'autre. Néanmoins, on ne constate pas au cours de ces quatre années de chute dramatique de la densité des populations. Ceci suggèrent que la pérennité des populations de Corbicula de la Saône et du Rhône est largement assurée par la dérive d'individus provenant du cours supérieur de ces cours d'eau et de leurs affluents. Deux causes sont proposées pour expliquer les faibles recrutements observés : - la faible production de phytoplancton ne permettrait pas aux adultes de constituer les réserves énergétiques nécessaires aux complet développement des larves ; - la contamination toxique inhibitrice du développement phytoplanctonique serait létale pour les pediveligers.

International audience; Community convergence across biogeographically distinct regions suggests the existence of key, repeated evolutionary mechanisms relating community characteristics to the environment. However, convergence studies at the community level often involve only qualitative comparisons of the environment and may fail to identify which environmental variables drive community structure. We tested the hypothesis that the biological traits of fish communities on two continents (Europe and North America) are similarly related to environmental conditions. Specifically, from observations of individual fish made at the local scale (few m2) within French streams, we generated habitat preference models linking traits of fish species to local scale hydraulic conditions (Froude number). Using this information, we then predicted how hydraulics and geomorphology at the larger stream reaches scale (length of streams including several pool-riffle sequences) should quantitatively influence the trait composition of entire communities. Trait composition for fish in stream reaches with low Froude number at low flow or high proportion of pools was predicted as non-benthic, large, fecund, long-lived, non-streamlined, and weak swimmers. We tested our predictions in contrasting stream reaches in France (n=11) and Virginia, USA (n=76), using analyses of covariance to quantify the relative influence of continent versus physical variables on fish traits. Results indicated that trait proportions in the communities differed across continents (up to 55 % of the variance in each trait explained), but, within continents, they were also related to the hydraulic and geomorphic variables (up to 54 % of the variance within continents explained). In particular, a synthetic description of fish traits was well predicted from the Froude number independently of the continent. In addition, the effect of physical variables was comparable across continents for most traits, confirming our predictions qualitatively and quantitatively. Therefore, despite phylogenetic and historical differences between continents, fish communities of France and Virginia exhibit convergence in biological traits related to hydraulics and geomorphology. This convergence reflects morphological and behavioral adaptations to physical stress in streams. This study supports the existence of a habitat template for ecological strategies. Some key quantitative variables that define this habitat template can be identified by characterizing how individual organisms use their physical environment, and by using dimensionless physical variables which are suited to reveal common energetic properties in different systems. Overall, quantitative tests of community convergence are efficient tools to demonstrate that some community traits are predictable from environmental features.; Les traits des communautés de poissons (morphologie, comportement, reproduction) répondent de façon comparables aux conditions hydrauliques dans des tronçons de cours d'eau français et nord-americains. Ces observations sont quantitativement prévisibles par des observations faites en France à une autre échelle : celle des microhabitats au sein des tronçons de cours d'eau.

The conventional analysis of bioassays does not account for biological significance. However, mathematical models do exist that are realistic from a biological point of view and describe toxicokinetics and effects on test organisms of chemical compounds. Here we studied a biology-based model (DEBtox) which provides an estimate of a no-effect concentration (NEC) and we demonstrated the ability of such a model to adapt to different situations. We showed the basic model can be extended to deal with problems usually faced during bioassays like time-varying concentrations or unsuitable choices of initial concentrations. To reach this goal we report experimental data from Daphnia magna exposed to zinc. These data also showed the potential benefit of the model in understanding the influence of food on toxicity. We finally make some recommendations about the choice of initial concentrations and we propose a test with a depuration period to check the relevance and the predictive capacity of the DEBtox model. In our experiments, the model performed well and proved its usefulness as a tool in risk assessment., L'analyse conventionnelle des bioessais ne prend pas en compte la pertinence biologique. Cependant, des modèles biologiques existent, réalistes d'un point de vue biologique, qui décrivent la cinétique et les effets des produits chimiques sur les organismes tests. Nous nous sommes intéressés ici à un modèle à fondement biologique (DEBtox) qui fournit une estimation d'une concentration sans effet (NEC) et nous avons démontré la capacité d'adaption d'un tel modèle. Nous avons ainsi montré que le modèle de base peut être étendu pour traiter des problèmes rencontrés souvent au cours des bioessais comme des variations des concentrations d'exposition ou un mauvais choix des concentrations de départ. Pour cela, nous avons réalisé un test avec des daphnies (Daphnia magna) exposées au zinc. Ces données ont aussi montré l'intérêt du modèle pour comprendre l'influence de la nourriture sur la toxicité. Nous faisons, pour finir, quelques recommendations sur le choix des concentrations d'exposition et nous proposons un test avec une phase de dépuration pour vérifier la pertinence et la capacité prédictive du modèle DEBtox. Au cours de nos expérimentations, le modèle a passé ce test avec succès, démontré son utilité comme outil pour l'analyse du risque.

International audience; Hydrological and biotic forces constrain brown trout (Salmo trutta) population dynamics, but tests of their role across numerous streams are uncommon. In 30 French stream reaches, using 5-8 samples (1 per year) each, we investigated whether the year-to-year seasonal hydrology influenced annual trout densities within reaches, and whether the relationships were shared by all reaches. We also searched for intraspecific interactions between and within cohorts. Trout data were age class (0+, 1+, and adults) densities. For each year, hydrology was described using 13 variables, each computed for a reproduction, emergence, and growth period related to the biological cycle of trout. We used anal-yses of covariance (ANCOVA) to test how trout densities at year n - 1 and hydrology at year n influenced trout densi-ties at year n. High flows during emergence significantly reduced the 0+ densities, consistently across the 30 reaches. Then, 1+ and adult densities were linked, respectively, to 0+ and 1+ densities from the previous year. Analyses also re-vealed density-dependent survival mechanisms for the 0+ cohort, suggesting intracohort competition. Therefore, hydrol-ogy constrains trout dynamics only during the critical emergence period, after which intracohort interactions regulate the 0+ density. Such mechanisms, validated across 30 environmentally different reaches, seem to be fundamental to trout population dynamics.; Les forces hydrologiques et biotiques imposent des contraintes à la dynamique de population des Truites brunes; cependant, on a rarement évalué leur rôle simultanément dans un grand nombre de cours d'eau. À partir de 5-8 échantillons (1 par année) récoltés dans chacun de 30 tronçons de cours d'eau français, nous avons examiné si les variations de l'hydrologie d'année en année influencent la densité annuelle des truites dans un tronçon et si les relations obtenues s'appliquent à tous les tronçons. Nous avons aussi cherché à trouver des interactions intra-spécifiques au sein des cohortes et d'une cohorte à l'autre. Nos données consistaient en des densités des différentes classes d'âges (0+, 1+ et adulte). Nous avons mesuré, chaque année, 13 variables hydrologiques, regroupées selon les périodes d'émergence, de reproduction et de croissance du cycle biologique des truites. Des analyses de covariance (ANCOVA) nous ont permis de vérifier comment la densité des truites de l'année n -1 et l'hydrologie de l'année n pouvaient influencer la densité des truites de l'année n. Des débits élevés durant l'émergence réduisaient significativement les densités des truites d'âge 0+, de façon comparable dans tous les 30 tronçons. De plus, les densités des truites d'âges 1+ et adulte étaient reliées respectivement aux densités des poissons d'âges 0+ et 1+ de l'année précédente. Les analyses ont aussi mis en évidence des mécanismes de survie reliés à la densité chez la cohorte d'âge 0+, ce qui semble indiquer l'existence de compétition au sein de la cohorte. L'hydrologie impose donc des contraintes à la dynamique de population des truites seulement durant la période critique de l'émergence, après quoi ce sont les interactions au sein de la cohorte qui contrôlent la densité des poissons d'âge 0+. De tels mécanismes, observés dans 30 tronçons qui diffèrent par leurs conditions environnementales, semblent être des caractéristiques fondamentales de la dynamique de population des truites.

Young-of-the-Year (YOY) cyprinid recruitment success was investigated annually over a 16-year period (from 1983 to 1998) in relation with the annual hydrological regime in a large regulated river (the Rhône River, France). The annual discharge regime was divided among 3 seasons based on the biological cycle of fishes (wintering, reproduction, and growth periods), and characterised by descriptors of average, high and low flow conditions, and overall variability. Co-inertia analysis revealed two distinct effects of hydrology on YOY recruitment success. The first resulted in a sudden shift in the YOY community organization, and was the consequence of two unpredictable (of extremely high magnitude in regard with the long-term mean value in a given time interval) consecutive floods, in October 1993 (110-year return-flood) and January 1994 (50-year flood). The resulting scouring of the substratum seems to have had a favourable effect on recruitment. The second, weaker effect was only observed in the 5 years after the 1993 and 1994 floods. It revealed the role of seasonality in hydrological conditions, because it separated high and variable discharge during the spawning period (favourable for barbel and bleak) from low discharge during this season (favourable for roach, rudd and nase). The results were consistent with previous knowledge concerning these species, and functional interpretations confirmed general expectations. Our findings support habitat template theories that attribute a major role to environmental variability (including 'disturbance history') in determining community characteristics. Finally, these results provide the first steps for a rational management of seasonal discharge in large regulated streams., Nous avons étudié le succès de recrutement annuel des Cyprinidés sur une période de 16 ans (1983-1998) en relation avec le régime hydrologique annuel dans un grand fleuve régulé (le Rhône). Le régime hydrologique annuel a été divisé en 3 saisons basées sur le cycle biologique des Cyprinidés (hiver, reproduction et croissance), et caractérisé par des descripteurs des conditions moyennes, de hauts et bas débits, ainsi que de la variabilité globale. Une analyse de co-inertie a révélé 2 effets distincts de l'hydrologie sur le succès de recrutement. Le premier s'est traduit par un changement très net dans l'organisation de la communauté alevine (forte augmentation des abondances et de la richesse spécifique), et est la conséquence de 2 crues consécutives de très fortes amplitudes (imprévisibles), en Octobre 1993 (crue de période de retour estimée à 110 ans) et Janvier 1994 (crue cinquantenale). Il semblerait que le nettoyage (décolmatage) du substrat consécutif à ces 2 événements ait agit favorablement sur le recrutement. Le second effet est plus faible, et n'est décelable que pendant les 5 années qui font suite aux crues de 1993-1994. Il met en évidence le rôle de la saisonnalité des conditions hydrologiques, en séparant les débits forts et variables durant la saison de reproduction (favorables au barbeau et à l'ablette) des débits faibles pendant la reproduction (favorable au gardon, rotengle et hotu). Ces résultats sont pertinents avec les connaissances que l'on a de ces espèces, ainsi que les interprétations fonctionnelles (traits biologiques). Nos résultats sont en accord avec les théories basées sur 'l'habitat template' qui attribuent un rôle prépondérant à la variabilité environnementale (incluant 'l'histoire des perturbations') dans la déterminations des caractéristiques biologiques et fonctionnelles de la communauté piscicole. Finalement, ces résultats peuvent servir de base à une gestion rationnelle des débits saisonniers dans les grands cours d'eau aménagés.

Although benthic stream macroinvertebrates have been widely used in biomonitoring, further developments towards more general biomonitoring tools are timely. Therefore, we compared traditional ways of biomonitoring such as diversity, biotic indices and community structure with a new approach using biological traits such as reproduction, life duration, and feeding habits. These approaches were applied to a typical biomonitoring scenario, i.e. for two sites being upstream and downstream of the effluent from a waste water treatment plant. Physico-chemical variables did not discriminate between upstream and downstream site. Among eight tested biological indices, only Margalef's and Shannon's index and the French Biotic Index "indice biologique global normalisé" (IBGN) significantly separated the upstream from the downstream site. However, biomonitoring through these three indices depended significantly on the sampling effort, which was not the case for the community structure or biological traits. Community structure in terms of taxa abundances separated the upstream from the downstream site (17.9 % of discrimination). Biological traits weighted by taxa abundances better separated the upstream from the downstream site (23.1 % of discrimination). The biological traits showed that the functional structure at the upstream site was characteristic for organisms using the strategy of resilience in more variable but less adverse environments. In contrast, the functional structure observed at the downstream site was characteristic for organisms using the strategy of resistance in less variable but more adverse environments. Thus, the functional approach to indicate pollution effects in streams through biological traits may provide a tool for future stream management which is robust, general and based on current concepts of ecological theory., Bien que les macroinvertébrés benthiques aient été largement utilisés dans la bioindication, de nouveaux développements vers des outils de bioindication plus généraux sont nécessaires. Par conséquent, nous avons comparé des méthodes de bioindication traditionnelles telles que les indices de diversité, les indices biotiques et la structure des communautés avec une nouvelle approche utilisant les traits biologiques tels que la reproduction, la durée de vie, et les habitudes alimentaires. Ces approches ont été appliquées à un cas typique de bioindication, c'est à dire sur deux sites étant en amont et en aval d'un effluent de station d'épuration. Les variables physico-chimiques n'ont pas discriminé le site amont du site aval. Parmi les huit indices biologiques testés, seuls les indices de Margalef et de Shannon et l'indice biotique français "indice biologique global normalisé" (IBGN) ont significativement séparé le site amont du site aval. Cependant, l'indication biologique fournie par ces trois indices dépendait significativement de l'effort d'échantillonnage, ce qui n'était pas le cas pour la structure des communautés et les traits biologiques. La structure des communautés en terme d'abondances taxonomiques a séparé le site amont du site aval (17,9 % de discrimination). Les traits biologiques pondérés par les abondances taxonomiques ont mieux séparé le site amont du site aval (23,1 % de discrimination). Les traits biologiques ont montré que la structure fonctionnelle observée au site amont était caractéristique d'organismes utilisant la stratégie de la résilience dans des environnements variables mais à faible adversité. Au contraire, la structure fonctionnelle observée au site aval était caractéristique d'organismes utilisant la stratégie de la résistance dans des environnements stables mais à forte adversité. Ainsi, l'approche fonctionnelle, utilisée pour indiquer les effets des pollutions dans les cours d'eau à partir des traits biologiques, peut constituer un outil pour la gestion future des cours d'eau, qui est robuste, général et basé sur des concepts actuels de théories écologiques.

Effect of Methidathion (organophosphate) on the P450 1A induction was assessed both by measurements of the induction of the EROD activity and of the immunodetection of the CYP 1A protein in gudgeon. Fish were pre-treated with 5 mg/kg of beta-Naphthoflavone (BNF) and exposed to environmental concentrations of methidathion in aboratory. Methidathion proved to inhibit EROD induction in vivo and in vitro. In contrast, levels of immunoquantified CYP1A were found to be slightly higher in microsomes from fish exposed to 10-30 µg/L of methidathion than in control fish exposed to BNF alone. This suggests that the inhibition of the EROD activity by methidathion resulted from a catalytic inhibition without decrease of the CYP1A protein., L'effet du méthidathion (organophosphoré) sur l'induction du cytochrome P450 1A a été évalué par deux méthodes complémentaires : la mesure de l'activité EROD et l'immunodétection de la protéine. Les poissons sont exposés à des concentrations environnementales de méthidathion après une pré-injection à 5mg/kg de beta-naphthoflavone (BNF). L'activité EROD est inhibée par le méthidathion à la fois in vivo et in vitro. En revanche les niveaux en protéine P450 1A immunodétectés sont légèrement induits aux concentrations supérieures en méthidathion, ce qui suggère une inhibition catalytique.

The longitudinal distribution of Trichoptera at 37 sampling sites along 800 km of the Loire River (France) was analyzed in order to better understand large-scale changes in community structure occurring on a stream continuum. Different simple ordination methods- centered PCA and Correspondence Analysis - were performed to investigate these changes. Both analyses showed that a major change occurs in the community in the upper reaches of the Loire River between the Serre de la Fare and Vorey sampling sites with the appearance of Hydropsyche contubernalis and H.exocellata. Even though other changes in community structure could exist, revealed either by Correspondence Analysis at the first sampling sites (crenal), or by PCA at sampling sites influenced by dams, this Trichoptera community appears to be stable enough in the latter part of the Loire River with the addition of a few species, Hydropsyche bulgaromanorum, Ecnomus tenellus and Ecnomus deceptor, rather than changes in species. The results are discussed in the light of different concepts in stream ecology, and the validity of such data analyses to describe some community patterns., La distribution longitudinale des trichoptères en 37 points d'échantillonnage le long de 800 kilomètres du fleuve Loire (France) a été analysée afin de mieux comprendre les changements à grande échelle des structures de communauté le long d'un continuum fluvial. Différentes méthodes d'ordination simple - ACP centrée et analyse factorielle des correspondances - ont été réalisées pour examiner ces changements. Les deux types d'analyses ont montré qu'un changement majeur apparaissait dans la communauté dans les stations de l'amont de la Loire entre les sites de Serre de la Fare et Vorey avec l'apparition d'Hydropsyche contubernalis et d'H. exocellata. Même si d'autres changements dans la structure de communauté existent, révélés soit par l'analyse des correspondances factorielles sur les premiers sites de l'amont (crénon), soit par l'ACP sur les sites d'échantillonnages influencés par les barrages, cette communauté de trichopères semble stable surtout dans la partie avale du fleuve Loire avec l'apparition de quelques espèces Hydropsyche bulgaromanorum, Ecnomus tenellus et Ecnomus deceptor, plutôt que des changements spécifiques. Les résultats sont discutés en lumière des différents concepts en écologie des eaux douces, et de la validité de ces types d'analyses pour décrire des modèles de communauté.

The essay concerns an array of graphic works the author calls 'dynamographies'. These images do not only localize movement by graphic means but reveal new forms of movement. In dynamography, rhythm makes visible a movement dissociated from linear time – not in order to abolish temporality, but in order to multiply it into a diversified 'heterochrony'. Starting from a range of drawings, notes, and notations by the poet Andrei Bely, the essay analyzes Bely's 'life lines' alongside Marey's chronophotography, Warburg's 'dynamograms', and Eisenstein's exercises in 'mise-en-scène'.

Using an air-lift pump, groundwater invertebrates of a fractured limestone site recharged with secondary sewage were collected by means of a dense network of deep observation wells. The spatio-temporal distribution of organisms throughout the dendritic system of interconnected joints and fissures was closely related to the heterogeneous groundwater and sewage flow pattern. During low water periods with high infiltration rates of sewage, groundwater communities were displaced upstream or downstream of the study area and were also disseminated throughout the adjacent fissure network. They were associated with hypogean organisms, which were only collected when pristine groundwater circulated through the openings of the site., Les invertébrés d'un site calcaire fissuré rechargé avec des eaux usées secondaires ont été recueillis à l'aide d'un réseau dense de puits d'observation. La répartition spatio-temporelle des organismes à travers le système dendritique de joints et de fissures reliés était étroitement lié aux nappes phréatiques hétérogènes et au schéma d'écoulement des eaux usées. Pendant les périodes d'étiage avec des taux d'infiltration élevés des eaux usées, les populations des nappes phréatiques ont été déplacées en amont ou en aval de la zone d'étude et ont aussi été disséminées dans le réseau de fissures adjacent. Ils ont été associés à des organismes hypogés qui n'étaient collectés que lorsqu'une eau souterraine pure circulait à travers les ouvertures du site.

Le pr incipe genera l des disposi t i fs de f rancf i i ssement consis te a attirer les migrateurs en un point determine du cours d'eau a l'aval de l'obstacle et a les inciter, voire a les obliger a passer en amont, en leur ouvrant une voie d'eau (passes a poissons stricto sensu) ou en les piegeant dans une cuve et en deversant celle-ci en amont (ascenseurs et systemes de piegeage et de transport).

Les rejets d'eau chaude du Centre de Production Nucleaire du Bugey entrainent jusqu'a 5 km en aval de la centrale, une elevation de la temperature des eaux du Rhone de 6 °C en moyenne. L'echauffement des eaux est encore sensible au niveau de la confluence avec l'Ain. Suite a l'etude d'impact realisee en 1975 dans le cadre de la mise en service de ce centre, une reactualisation des donnees s'averait necessaire sur le site pour effectuer un bilan de l'impact reel des rejets thermiques sur les biocenoses. L'examen de la faune benthique met en evidence une diminution notable de la richesse taxonomique sur l'ensemble du site entre 1975 et 1988-89. Ainsi, Rhithrogena diaphana, Ecdyonurus sp.(ephemeropteres) et les representants de la famille des Unionidae (mollusques) sont absents en 1988, la densite des oligochetes a diminue depuis 1975 sur le point amont. Au niveau de la station echauffee, on observe en 1988-89 une reduction significative de la richesse taxonomique des invertebres, avec notamment la disparition de Potamanthus luteus (ephemeroptere) et de Propappus volki (oligochete). On constate egalement une diminution de la densite des Chironomidae et des oligochetes, ces derniers, ainsi que les Gammaridae, disparaissant durant la periode la plus chaude (aout, septembre).

National audience; Le PNSE de 2004 2008 demandait aux agences de l'eau de faire des investigations dans ce nouveau domaine. Des études de recherche de ces substances, et pour certaines de leurs métabolites, ont été conduites de manière spécifique selon les bassins. Les trois types de milieu ont été prospectés : les cours d'eau, les eaux souterraines et les estuaires. Selon les partenaires, des investigations plus poussées ont été opérées sur les eaux de consommation brutes ou distribuées, et sur les rejets des stations d'épuration urbaines. Le choix des molécules repose bien évidemment sur leur pertinence en matière de quantité utilisée (et excrétée), mais également sur leur persistance dans le milieu et la disponibilité de méthodes d'analyse à des seuils très bas (de l'ordre du nanogramme/L). Des spécificités ont été développées selon les laboratoires impliqués. Dans les rejets des collectivités se détache un panel de substances assez constant quels que soient les sites (psychotropes, analgésiques, hypolipémiants), avec des concentrations de l'ordre du microgramme/l. Pour les hormones la gamme s'étend du non quantifiable à quelques ng/L.

International audience; In 2005, the Society of Environmental Toxicology and Chemistry (SETAC) published a thorough review on Sediment Quality Guidelines (SQGs) and their uses. One of its main conclusions was that these indicators were more appropriate as benchmarks in tiered approaches to environmental quality or risk assessment than as standards in the restrictive sense of values triggering management decisions. Nevertheless, the Water Framework Directive requires environmental quality standards (EQS) also for sediments; the proposed Priority Substances directive, which currently left the issue unsolved, cannot accordingly be adopted as such. A working group (EG-EQS) has been set up by the European Commission to find a sustainable way of fulfilling the WFD requirements whilst using sound (and shared) scientific concepts. This presentation will summarise the challenges faced by the group, with focussing on organic substances. Our aim is to stimulate debate about the options being considered for setting sediment standards.

[Departement_IRSTEA]MA; International audience; It is widely accepted that evolutionary changes in conserved developmental signaling pathways play an important role in morphological evolution. However, few in silico studies were interested in tracking such changes in a signaling pathway. The Ectodysplasin (EDA) pathway provides an opportunity to fill this gap because it is involved in vertebrate skin appendage development such as scales, teeth, hair, and feathers that take an obvious part in the adaptation of species to their environment. We benefited from the large amount of genomic data now available to explore the evolution of the upstream genes of the EDA pathway. In mammals, these genes are eda (encoding 2 ligands, EDA-A1 and EDA-A2), edar (EDA-A1 receptor), edaradd (EDA receptor [EDAR] adapter), xedar (EDA-A2 receptor), and troy (a XEDAR-related receptor). We show that the evolution of EDA pathway genes combines both strongly conserved features and evolutionary shifts. These shifts are found at different signaling levels (from the ligand to intracellular signaling) and at different taxonomic levels (class, suborder, and genera). Although conserved features likely participate to the similarities found in the early development of vertebrate skin appendages, these shifts might account for innovations and specializations. Moreover, our study demonstrates that we can now benefit from the large number of sequenced vertebrate genomes to explore the evolution of specific signaling pathways and thereby to open new perspectives for developmental biology and evolutionary developmental biology.

The aim of this study was to investigate the effects of cadmium on physiological and behavioural responses in Gammarus pulex. In a first experiment, cadmium LC50s for different times were evaluated in 264 h experiment under continuous mode of exposure (LC50(96 h)=82.1 microgL(-1), LC50(120 h)=37.1 microgL(-1), LC50(168 h)=21.6 microgL(-1), LC50(264 h)=10.5 microgL(-1)). In a second experiment, the physiological and behavioural responses of the amphipod exposed to cadmium (0, 7.5 and 15 microgL(-1)) were investigated under laboratory conditions. The mortality and the whole body cadmium concentration of organisms exposed to cadmium were significantly higher than in controls. Concerning physiological responses, cadmium exposure exerted a significant decrease on osmolality and haemolymph Ca(2+) concentration, but not on haemolymph Na(+) and Cl(-) concentrations, whereas the Na(+)/K(+)-ATPase activity was significantly increased. Behavioural responses, such as feeding rate, locomotor and ventilatory activities, were significantly reduced in Cd exposed organisms. Mechanism of cadmium action and consequent energetic reallocation in favour of maintenance functions (i.e., osmoregulation) are discussed. The results of this study indicate that osmolality and locomotor activity in G. pulex could be effective ecophysiological/behavioural markers to monitor freshwater ecosystem and to assess the health of organisms.

International audience; The St. Lawrence River is one of the most world's largest watercourses. This river, an essential waterway for North America, is exposed to many anthropogenic stresses, as 97% of the Quebec population is living in its watershed. This study is a part of a large research project aiming at developing an ERA tiered framework for sediment management, in the context of integrated management of contaminated sediment, site restoration and sustainable navigation. The purpose of this study is to assess sediment quality by exploring the relationships between chemical contamination and benthic community structure using classical taxonomy and functional traits approaches. During falls 2004-2005, macroinvertebrates were collected in 59 sites in the St. Lawrence River, especially in its three fluvial lakes and in the harbour zone of Montreal. Organic (PCBs, PAHs, petroleum hydrocarbons), inorganic (As, Cd, Cu, Cr, Hg, Ni, Pb and Zn) contaminants and sediments characteristics (e.g. grain size, metal-binding phases, nutrients) were measured in whole sediment. Different descriptors (taxonomy and functional traits) of benthic macroinvertebrates in the St. Lawrence levels are used to assess the relative impact of chemical contamination and sediment characteristics on macroinvertebrate community, using multivariate analysis and variance partitioning. We compared the potential of taxonomy and functional traits approaches for assessing sediment contamination and toxicity. We also established sediment classification with different methods such as benthic community (taxonomy or traits), bioassay and chemical concentrations based on St. Lawrence River sediment quality guidelines. Implication for the development of an ERA tiered framework will be discussed. This research is being carried out within the context of a cooperation program involving the Groupe de Recherche Interuniversitaire en Limnologie et en Environnement Aquatique (GRIL) at the Université de Montréal, Environment Canada, the Ministère du Développement Durable, de l'Environnement et des Parcs du Québec, and Cemagref groupement de Lyon.

International audience; Quantitative genetics protocoles were performed to estimate the genetic part of the variability of sensitivities to cadmium among individuals from a field population of Gammarus pulex and the heritability of this trait. Pairing between breeders was monitored to supply two nested full-sib, half-sib mating designs. The survival of 356 juveniles was recorded during a continuous exposure to 20 µg/L of cadmium. A significant part of the variability was explained by differences in sensitivity between full sibships. Only non-additive genetic variance (dominance) or sibship-specific maternal effect could be in cause. The decomposition of the genetic variability of toxic sensitivity between additive and non-additive components is here of broad interest because it conditions the possibility that a selection process could arise in case of sexual reproduction. Then quantitative genetics protocoles appear to be achievable to predict a priori the possiblity of adaptation to toxic stress.

La problématique qui a engendré l'étude décrite dans ce rapport [est-ce qu'une augmentation importante de la concentration en NH4+ en rivière au début des vacances de Noël a un impact sur la vie aquatique ?] émarge à l'interface habitat, chimie et biologie (réponses des communautés), sans pour autant rencontrer les thèmes de recherche d'un seul laboratoire du Cemagref de Lyon. L'étude réalisée a donc exigé des techniques et des connaissances impliquant la collaboration de plusieurs laboratoires. Cette première approche avait pour objectif de débuter une recherche bibliographique sur le thème abordé et la réalisation d'une première expérimentation.

International audience; Effects of flow intermittence have been poorly investigated in the subsurface of streams. Hyporheic invertebrate assemblages may be controlled by: flow permanence; taxa tolerance to desiccation; refuge availability (presence of groundwater); recolonisation dynamic after rewetting. We used a combination of natural and lab experiments to better understand faunal dynamics in the HZ of an intermittent alluvial river, the Selwyn river.

Human pharmaceuticals are widely used and can reach surface waters via wastewater treatment plants (WWTPs), where they have the potential to exert biological effects on aquatic non-target organisms. Due to the high number of pharmaceutical drugs used in human medicine, it is necessary to select the pharmaceuticals to search for, prior to implementing any extensive environmental risk assessment (ERA). In order to define such a selection, we developed an original prioritisation methodology (Besse and Garric, 2008). A preliminary classification based on the assessment of the exposure is implemented using two main parameters: consumption amounts of pharmaceuticals and human metabolism data. The preliminary classification is then reviewed on a case-by-case hypothesis basis using available biological data: ecotoxicological, pharmacological (mechanism of action (MoA), enzyme modulation, adverse effects) and physicochemical data (logKow). Here, we present the implemented methodology and discuss its relevance, benefits and limits.

The availability and bioaccumulation of metals and metalloids, and the geochemical interactions among them, are essential to developing an ecological risk assessment (ERA) framework and determining threshold concentrations for these elements. The purpose of this study was to explore the relationships among total recoverable and reactive metals and metalloid in sediment and their bioaccumulation by chironomids. In the fall of 2004 and 2005, 58 stations located in the three fluvial lakes of the St. Lawrence River and its largest harbour area in Montreal, Canada, were sampled. Nine total recoverable and reactive metals (Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) and one metalloid (As) were measured in whole sediment using two extraction methods: HCl/HNO 3 and HCl 1N, respectively. The bioaccumulation of six metals (Cd, Cr, Cu, Ni, Pb and Zn) and As by chironomids was evaluated in a subset of 22 stations. Strong collinearities were observed between some total recoverable or reactive metal concentrations in sediment; two principal clusters, including collinear metals, were obtained. The first one included metals of mainly geological origin (Al, Cr, Fe, Mn, Ni), while the second one included As, Cd, Cu, Pb and Zn, which likely derive mainly from point sources of anthropogenic contamination. Each element also showed strong collinearity between their total recoverable and reactive forms (0.65 ≤ r ≤ 0.97). We can conclude that both chemical forms are equivalent for use in statistical models needed to explain biological responses and also in screening risk assessment. However, these relationships are not always proportional. Lower availability percentages were observed for Cd, Cu and Zn in the highly mixed-contaminated area of the Montreal Harbour, even though concentrations in sediment were higher. We observed a significant correlation (0.50 ≤ r ≤ 0.56) between concentrations in chironomids and concentrations of both total recoverable and reactive Cr and Pb in sediment. Arsenic was an exception, with accumulation by chironomids being highly related to reactive sediment concentrations. Finally, we observed variable influences of explanatory factors (e.g. sediment grain size, Al, Fe, Mn, S, TOC), depending on which metal or metalloid was being predicted in chironomids. In this context, it is difficult to choose a universal predictive method to explain the bioaccumulation of specific metals, and more research is still needed into normalization procedures that consider a combination of explanatory factors.