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La pêche à l’électricité est une méthode classiquement utilisée pour les inventaires de biodiversité des poissons et crustacés dans le cadre de la surveillance réglementaire de l’état écologique des cours d’eau. Elle pose un certain nombre de difficultés en territoires ultramarins tropicaux, de par certaines spécificités physiques (conductivité de l’eau basse à très basse) et écologiques (communautés mixtes de poissons et de crustacés, biodiversité forte à très forte) qui les caractérisent. Issues du partenariat OFB-INRAE, les recherches menées en collaboration avec l’entreprise HYDRECO-Guyane ont permis de définir des conditions spécifiques d’application de la pêche à l’électricité pour les petits cours d’eau (< 6 mètres de large) tropicaux. Grâce à des essais au laboratoire et in situ, en Guyane, aux Antilles et à La Réunion, nous avons identifié les réglages électriques les plus efficaces pour la capture, l’estimation de la richesse spécifique et de l’abondance des espèces et le respect de la santé animale. Ces recherches se placent dans l’objectif plus large d’améliorer la qualité des données bancarisées pour le suivi environnemental des masses d’eau. Elles donnent lieu à des recommandations pour la maitrise d’œuvre et la maitrise d’ouvrage de la pêche à l’électricité en petits cours d’eau tropicaux.

The growing threat of abrupt and irreversible changes to the functioning of freshwater ecosystems compels robust measures of tipping point thresholds. To determine benthic cyanobacteria regime shifts in a potable water supply system in the tropical Andes, we conducted a whole ecosystem-scale experiment in which we systematically diverted 20 to 90% of streamflow and measured ecological responses. Benthic cyanobacteria greatly increased with a 60% flow reduction and this tipping point was related to water temperature and nitrate concentration increases, both known to boost algal productivity. We supplemented our experiment with a regional survey collecting > 1450 flow-benthic algal measurements at streams varying in water abstraction levels. We confirmed the tipping point flow value, albeit at a slightly lower threshold (40-50%). A global literature review broadly confirmed our results with a mean tipping point at 58% of flow reduction. Our study provides robust in situ demonstrations of regime shift thresholds in running waters with potentially strong implications for environmental flows management.

Agriculture greatly impacts water resources due to the high volumes of irrigation water consumed in crop production. Additionally, agricultural activities affect hydrological cycles through land-use changes and soil modifications, which may lead to pollution of water bodies. On a local level, these impacts and specific improvement options can be assessed by risk assessment and integrated water resource management. Modelling the impacts of agriculture on freshwater comprehensively is a difficult task as freshwater can be impacted by water consumption and also by water pollution. These are influenced by direct agricultural activities (e.g. irrigation) as well as by indirect activities for the production of agricultural inputs (e.g. fertilizers, agrochemicals). This chapter looks at modelling the impacts of agriculture on freshwater. Following an introduction, the authors go on to look at modelling in relation to water consumption, water quality and salinization. The chapter also covers soil quality, land use and both geographical and temporal variation. Case studies are also included.

Bien que la pêche soit très présente dans la culture québécoise, la gestion et la conservation des poissons d’eau douce et des poissons migrateurs du Saint-Laurent sont peu connues du public. L’objectif de cet article est de présenter les acteurs, le cadre législatif et les pratiques de gestion applicables à ces espèces dans les eaux douces et saumâtres du Saint-Laurent. La croissance des usages du territoire québécois, déjà nombreux, génère des pressions grandissantes sur la faune et les habitats du Saint-Laurent. Cette réalité force à sortir des modèles classiques de gestion et à recourir à des approches globales nécessitant de protéger des habitats multi spécifiques plutôt qu’une espèce en particulier, et d’impliquer des intervenants provenant, entre autres, des domaines agricole, industriel et municipal. Dans le futur, les principaux défis consisteront à rassembler les acteurs liés au Saint-Laurent autour des cibles communes de restauration et de mise en valeur, de maintenir une expertise de pointe et de continuer à appuyer la gestion de la faune aquatique sur des données scientifiques rigoureuses. Dans un contexte de changements climatiques, où la menace liée aux espèces exotiques envahissantes et les pressions de diverses natures sont exercées sur les habitats, il sera primordial d’appliquer une gestion proactive en déployant les mesures nécessaires dès que l’état de situation d’une espèce le suggérera. L’état précaire de certaines populations, comme la perchaude du lac Saint-Pierre, doit d’ailleurs être interprété comme un indicateur parmi d’autres de la détérioration de certaines fonctions de l’écosystème exceptionnel que représente le Saint-Laurent et des défis qui devront être relevés dans le futur. Tous les défis ne sont cependant pas associés à des situations de déclins. Les exemples de la réintroduction du bar rayé et du rétablissement de l’esturgeon jaune démontrent, lorsque des mesures de gestion adéquates sont prises, que le système peut être résilient et que le futur peut être prometteur., While fishing is culturally important in Québec (Canada), public knowledge about the management and conservation of freshwater and migratory fish in the St. Lawrence River is generally poor. This article aims to present the key players, the legislative framework, and the management practices as applicable to fish species in the freshwater and brackish portion of the St. Lawrence in Québec. Human pressure throughout the southern part of the province continues to increase and this has important impacts on the habitats of the St. Lawrence, and the wildlife using them. This reality must be addressed using new global approaches, such as protecting multi-species habitats, rather than focusing on more traditional single-species management and protection plans. New approaches should also involve stakeholders from the agricultural, industrial and municipal sectors, among others. In the future, the main challenges will be to achieve consensus between stakeholders for the fixing of common targets for restoration and development; to maintain cutting-edge expertise; and to continue supporting the management of fisheries on a rigorous scientific basis. In the context of climate change, where invasive exotic species and a range of anthropogenic alterations add increased pressure on habitats, it will be important to implement a proactive management approach, allowing rapid action to be taken as soon the status of a species indicates that it is needed. The precarious status of some species, such as the yellow perch in the Lake Saint-Pierre area, is another indicator of the profound deterioration and the loss of key ecological functions of the St. Lawrence ecosystem, and the challenges that will have to be met in the future. The reintroduction of the northernmost population of striped bass and the successful reestablishment of lake sturgeon stocks highlight the potential for meeting these challenges, and restoring the St. Lawrence River and its species. These examples show that the future can be positive if the appropriate management actions are implemented when required.

Deformities in diatoms are increasingly used as an indicator of toxic stress in freshwaters. However, the percentage of deformities alone often fails at highlighting the magnitude of toxic exposure. An approach combining the assessment of deformities coupled with information on their severity could improve the sensitivity of this biomarker. With the aim of quantifying the deviation from the normal form, we tested the applicability of geometric morphometry to evaluate the degree of deformities in different diatom species. We used photomicrographs of normal and deformed specimens from laboratory cultures of Gomphonema gracile, Nitzschia palea, and of Achnanthidium minutissimum from field samples collected along a gradient of toxic contamination. The geometric morphometry approach is based on several landmarks positioned on the outline of the diatom valves. Statistical analyses were conducted based on the geometrical coordinates of the landmarks. This technique allowed to discriminate between normal and deformed individuals. The geometric morphometry approach revealed a gradient in the intensity of the deformities observed on Gomphonema gracile and Achnanthidium minutissimum, in-line with a priori, visually determined (subjective) classifications. A relationship between the degree of deformity in Achnanthidium minutissimum and a gradient of zinc contamination was found. In contrast, the approach failed to obtain good fit for Nitzschia palea individuals because deformities in this species were more variable in terms of their location on the valves. Geometric morphometry provided encouraging results to objectively quantify the intensity of diatom deformities affecting valve outline, and could easily be implemented in further automatic diatom identification developments.

L’outil de comptage PHYTOBS permet le comptage du phytoplancton au microscope. Il est conforme à la norme Utermöhl, NF-EN 15204, relative au comptage du phytoplancton en microscopie inversée. De même il respecte le protocole standardisé d’échantillonnage du phytoplancton en plan d'eau dans le cadre de la DCE et peut de ce fait servir aussi dans cet optique. Le comptage d’un échantillon selon deux stratégies différentes est aussi possible. Différentes options et fonctions permettent de synthétiser et d'exporter les résultats en vue de la bancarisation, de calculer des biovolumes ou encore de quantifier le biovolume de cyanobactéries potentiellement productrices de cyanotoxines. Il permet de réaliser des calculs de l’indice phytoplancton lacustre (IPLAC) et d’en exporter les résultats de manière synthétique et illustrée. Un des boutons permet d’accéder à la liste taxinomique de référence des algues potentiellement rencontrées en France avec leur phylogénie et leur codification SANDRE. Ce logiciel, libre de droit, est sous licence GPL v3. Il a été déposé en 2017 à l’Agence pour la Protection des Programmes (APP) et possède la référence Inter Deposit DigitalNumber suivante : IDDN.FR.001.530010.000.S.C.2017.000.30200.

The majority of studies on biofilms have focused on autotrophic and bacterial taxa, without considering the potential effects on biofilm grazers. In this work, we investigated the effects of realistic environmental concentrations of zirconium (Zr) on periphyton algal growth and micromeiofauna biodiversity. Glass slides were submerged in a pond for four weeks to colonize biofilms and exposed for four weeks in aquaria to targeted Zr concentrations of 0, 1, and 10 nM, which were monitored over time (average measured concentrations were 0.2 &plusmn, 0.1, 0.5 &plusmn, 0.3, and 2.9 &plusmn, 0.3 nM Zr). The four-week exposure to the highest concentration (3 nM) affected the micromeiofauna structure of biofilms and modified the autotrophic biofilm structure by increasing the proportion of green algae and decreasing the abundance of cyanobacteria and brown algae. Rotifers and the ciliate Aspidisca cicada appeared to be the most sensitive organisms among the observed micromeiofauna. A toxic effect of Zr on rotifers could explain such results. Indirect effects, such as reduced food availability given the reduced algal growth in the presence of Zr, could also play a role in the changes of micromeiofauna community structure. These results are among the few published data on the effects of Zr.

1. Viruses are the most abundant biological entities on the planet, and sediments provide a highly suitable environment for them. This review presents the first comparative synthesis of information on the fresh water and marine viriobenthos and explores differences and similarities to the better known virioplankton. We present methods for studying life cycles of the viriobenthos, data on viral distribution and diversity, interactions with host microbes, and information on the role of viruses in benthic food webs and biogeochemical cycles. 2. Most approaches developed for the virioplankton are also applicable to viriobenthos, although methods for analysing benthic viruses may differ in important details. 3. Benthic viruses are very abundant in both marine and freshwater sediments, where 107–1010 can occur in 1 g of dry sediment. Although information on viral production (VP) and decay rates in freshwater sediments is very limited, the data suggest that VP and decay could also be high. These data highlight the potential ecological importance of benthic viruses, suggesting that they could play a key role in prokaryotic mortality and in biogeochemical cycles. 4. There is clear indirect evidence for the importance of viriobenthos in marine and freshwater ecosystems. However, large numbers of visibly infected cells have not been observed, suggesting limited effects on prokaryote population and community dynamics. The apparent paradox between high viral abundance and low impact is currently unresolved, while several aspects of viral life cycles in sediments (e.g. chronic infection) are almost completely unknown. 5. Studies on viriobenthic diversity and community structure are at a pioneering stage. First results from a few studies using pulsed-field gel electrophoresis and especially from metagenomic analyses indicate, however, that viriobenthic assemblages are both highly diverse and distinct from the virioplankton. 6. Estimates of global viral abundance in the top 1 m of fresh water and marine sediments are 0.5 and 28.7 · 1028 viruses respectively. Similar rough estimates of production are 0.6 and 34.4 · 1028 viruses day)1, suggesting an average turnover time of 20 h.

Many urban centres in the Pacific islands have witnessed rapid growth and considerable cultural transition. Despite well-meaning and considerable efforts to improve water service delivery, there usually remain very real concerns relating to the limited supply of freshwater and notoriously poor water quality. Many water developments fail due to lack of ownership and ultimately from naïve assumptions about the socio-cultural contexts in which solutions are applied. Owing to a range of inter-relations and socio-cultural considerations, water development under these circumstances is a complex task that typically cannot be approached in a simplistic manner. Magnus Moglia, Pascal Perez and Stewart Burn describe three archetypes for water development (techno-centric, micro-credit and companion modelling), but in the end identify the companion modelling approach as being more suitable for developing context-specific institutions. While this methodology is part of the preferred participatory approaches, applying it to a real-world context is not easy, and a number of lessons are described based on previous experiences in the atoll town of Tarawa. Development (2008) 51, 49–55. doi:10.1057/palgrave.development.1100451

Using the “CLIMBER-3α” coupled climate model of intermediate complexity, the effect of a stratification-dependent vertical diffusivity on the sensitivity of the Atlantic Ocean meridional overturning circulation to perturbations in freshwater forcing is investigated. The vertical diffusivity κ is calculated as κ ∼ N−α, where N is the local buoyancy frequency and the parameter α is a measure of the sensitivity of the vertical diffusivity to changes in stratification. Independent of α, the stratification of the deep ocean is weakly increased as a response to an anomalous freshwater flux in the North Atlantic in these experiments. In the region of freshwater forcing and north of it this is caused by the freshwater anomaly itself, but farther south it is associated with anomalously warm surface waters caused by a reduction of the northward oceanic heat transport. Subsequently, and in opposition to results from previous studies, the overturning is reduced by the anomalous freshwater flux, independent of the choice of α. However, the amount of reduction in overturning following a freshwater perturbation is found to depend critically on the choice of the mixing sensitivity α. If α < αcr, the response is similar to the model’s response using constant vertical diffusivity (α = 0). For α > αcr, a sharp increase of the sensitivity is found. The value of αcr is found to be between 0.5 and 1. A general feedback is proposed explaining this threshold behavior: if α is large, both positive and negative perturbations of stratification are amplified by associated changes in diffusivity. In the experiments presented here, this enhances the initial positive stratification anomaly in northern high latitudes, which is created by the anomalous freshwater flux. As a result, convection is strongly reduced, and the overturning is significantly weakened.

Population centres in low atoll islands have water supply problems that are amongst the most critical in the world. Fresh groundwater, the major source of water in many atolls, is extremely vulnerable to natural processes and human activities. Storm surges and over-extractions cause seawater intrusion, while human settlements and agriculture can pollute shallow groundwaters. Limited land areas restrict freshwater quantities, particularly in frequent ENSO-related droughts. Demand for freshwater is increasing and availability is extremely limited. At the core of many groundwater management problems are the traditional water ownership rights inherent in land tenure and the conflict between the requirements of urbanised societies and the traditional values and rights of subsistence communities living on groundwater reserves. Resource limitations and geographic isolation restrict the potential for increasing wealth through crop exports. Water governance reforms and the provision of knowledge to communities are critical. Regional water organisations, fostering self-support, are a key to developing island-adopted and owned solutions. © 2006 Elsevier Ltd. All rights reserved.

L’examen de Schilbe mystus (Linne, 1758) (Schilbeidae) et Citharinus citharus (Geoffroy Saint-Hilaire, 1809) (Citharinidae), captures respectivement dans les bassins de la Sanaga a Edea et de la Benoue a Lagdo, a revele la presence de deux especes nouvelles de Myxosporidies appartenant au genre Thelohanellus Kudo, 1993 : Thelohanellus njinei n. sp., parasite de l’intestin de Schilbe mystus et Thelohanellus lagdoensis n. sp., parasite de l’intestin chez Citharinus citharus . Des informations complementaires sont donnees sur la diagnose de Thelohanellus citharini , parasite anterieurement decrit au Tchad.

International audience; We reviewed 219 papers and built an inventory of 532 items of ecological evidence on multiple stressor impacts in rivers, lakes, transitional and coastal waters, as well as groundwaters. Our review revealed that, despite the existence of a huge conceptual knowledge base in aquatic ecology, few studies actually provide quantitative evidence on multi-stress effects. Nutrient stress was involved in 71% to 98% of multi-stress situations in the three types of surface water environments, and in 42% of those in groundwaters. However, their impact manifested differently along the groundwater-river-lake-transitional-coastal continuum, mainly determined by the different hydro-morphological features of these ecosystems. The reviewed papers addressed two-stressor combinations most frequently (42%), corresponding with the actual status-quo of pressures acting on European surface waters as reported by the Member States in the WISE WFD Database (EEA, 2015). Across all biological groups analysed, higher explanatory power of the stress-effect models was discernible for lakes under multi-stressor compared to single stressor conditions, but generally lower for coastal and transitional waters. Across all aquatic environments, the explanatory power of stress-effect models for fish increased when multi-stressor conditions were taken into account in the analysis, qualifying this organism group as a useful indicator of multi-stress effects. In contrast, the explanatory power of models using benthic flora decreased under conditions of multiple stress

L'influence du facteur thermique sur la contamination de la carpe par le 60Co a été étudiée pour 4 températures : 8 °C, 15 °C, 20 °C et 25 °C. Pour chaque expérience, un lot homogène de 10 individus, d'une masse initiale d'environ 2,3 g et nourris ad libitum, est introduit dans 5 litres d'eau, renouvelée tous les 3 à 4 jours et contaminée à raison de 1,2.105 Bq.l-1.Entre deux renouvellements, la concentration du 60Co dans l'eau décroît sensiblement et l'état ionique du radionucléide, introduit à 100 % sous forme cationique, évolue vers des formes anioniques et neutres. Ces deux faits sont liés au métabolisme des poissons dont la croissance pondérale est corrélée à la température, la distribution de la nourriture étant adaptée aux besoins des individus.Globalement, la quantité totale de radiocobalt fixée par les carpes apparaît très fortement liée au facteur thermique mais, selon le niveau des températures, des situations différentes se dégagent pour des mêmes écarts. Il n'y a pas proportionnalité comptéte entre élévation de température et accumulation du 60Co mais une augmentation discontinue témoignant de l'existence de paliers, dont le plus important se situe à 20 °C.Le facteur de concentration du 60Co est, par contre, peu influencé par le facteur thermique pour les écarts inférieurs à 10 °C ou quand la température maximale est inférieure à 20 °C. L'incidence de la température devient sensible quand les écarts dépassent 10 °C et notamment lorsque sont atteintes des valeurs correspondant à l'optimum thermique des carpes. A l'équilibre, le facteur de concentration moyen du 60Co est de 3,6 à 8 °C, 4,4 à 15 °C, 5,1 à 20 °C et 6 à 25 °C., The problems of simultaneous thermal and radionuclide pollutions have led to a number of laboratory and field studies of the temperature effects on the radioactive contamination of aquatic organisms. AMIARD and KHALANSKI (1981) concluded from their bibliographic study that a temperature rise generally has a positive effect on biological accumulation of radionuclides in freshwater organisms. Due to insufficient data, however, this conclusion does not appear to be substantiated for 60Co uptake by fish. An experimental study was therefore undertaken to assess the effect of temperature on 60Co uptake by Caprinus carpio.The importance of 60Co results from the fact that, apart from tritium, radioactive cobalt isotopes represent the major components of liquid wastes discharged from pressurized water reactors, which are widely operated in France (BARDIN et al., 1982; PICAT et al., 1986). The common carp (Caprinus carpio L.) was selected as the subject of this experimentation because of its wide geographic distribution and the frequency with which it is found in field samples, making it a suitable biological indicator (D'AUBENTON and SPILLMANN, 1978; FOULQUIER and PALLY, 1982; FOULQUIER et al., 1985).The effect of temperature on 60Co contamination of the carp was investigated by conducting the same experiment at four temperatures (8 °C, 15 °C, 20 °C and 25 °C) determined by ecological and physiological criteria. In each experiment, young carps with a mean weight of 2.3 g were placed in a tank containing 5 liters of water contaminated with 1.2 x 105 Bq.l-1 of 60Co. The water was renewed at intervals of 3 - 4 days. Modifications in the ionic form of the radio-active cobalt dissolved in the water were monitored by percolating filtered water samples through ion exchange resin columns. The carps were fed to satiation with an industrial food containing 12 % minerals, 8 % fats and 58 % proteins (dry weight) together with vitamins and trace elements including 0.2 mg.kg-1 of cobalt. Radioactivity levels in the fish were measured, after mild anesthesia, with a single-channel amplitude selector equipped with a thallium-activated flat sodium iodine probe.Between successive water renewals, the 60Co concentration diminished (Table 1) and the ionic form of the radionuclide remaining in solution was significantly modified. The 60Co was introduced in chloride form and was initially found exclusively as a cation; anionic or neutral forms appeared and became dominant after a few days (Figure 1). These two phenomena are probably related to the fish metabolism which is temperature dependent. Thus, food was distributed according to the individual requirements, and an exponential correlation was observed between the temperature and the weight gain in the carps (Table 1). The appearance of anionic and neutral forms may be attributed to excessive amounts of organic matter due to the presence of the fish and food (FUKAI and MURRAY, 1973; KILLEY et al., 1984). This evolution also results from a significant increase in ions such as HCO3-, Cl-, SO4--, PO4-- and NH4+ (FRITSCH and BAUDIN, 1984) which may combine with Co++ ions to form neutral molecules and anionic complexes (TRISHAN et al., 1981). Radioactive decay in the mater is also temperature-dependent : the amount of fecal matter, which strongly adsorbs radioactive cobalt, is proportional to the metabolic intensity in the fish.The overall 60Co uptake by the carps (Table 2) appears to be strongly related to the temperature, but the effect of a given temperature rise varied with the initial temperature (Table 4). The 60Co uptake was not fully proportional to the temperature rise, but was observed to increase in stepwise fashion indicating the existence of various thresholds. The most significant of these was noted at 20 °C, which is the lower limit of the optimum temperature range for carps.The 60Co concentration in th fish (Table 3) was influenced to a much lower extent by the temperature than the total uptake. Small temperature variations (5 - 7 °C) had little or no effect on the concentration factor; this was also true for larger variations, from 8 °C to 20 °C (Table 4). Temperature effects were only significant between 8 °C and 25 °C, and between 15 °C and 25 °C.The 60Co concentration variation in time was similar for all four temperatures, with two successive phases (Figure 2). It can be expressed mathematically by an exponential model based on the existence of several compartments in living organisms characterized by the influx and efflux rates for the element under consideration (GOLSTEIN and ELWOOD, 1971; AOYAMA and INOUE, 1973; PENTREATH, 1975; GONTIER, 1983). The maximum value and the time required to reach equilibrium were determined by extrapolation from the equations for the concentration factor variations. The results were 3.6 and 510 days at 8 °C, 4.4 and 220 days at 15 °C, 5.1 and 125 days at 20 °C, and 6 and 110 days at 25 °C. These values indicate that a temperature rise diminishes the time required to reach equilibrium and slightly increases the concentration factor by an amount that is statistically significant only for major temperature differences (Table 4).Detailed investigations of various freshwater species, notably Caprinus carpio, have demonstrated the decisive effect of temperature on metabolic activity in these animals (LEVESQUE, 1980). The results presented here indicate that the 60Co uptake rate in the carp is not proportional to the temperature rise as is generally the case for physiological processes. From a radiation protection standpoint, this observation suggests that the temperature is not an essential factor in 60Co contamination of freshwater fish.

Since 1930, throughout the Soviet period, this lakeside system was plundered for over 30 years and it is this plundering that is now at the heart of economic and environmental concerns. The disasterous management of lake Sevan in Armenia has led to the water level being lowered by 20 metres and a subsequent reduction in the potential of the lake. Ever since indépendance this environmental damage has been the basis for a huge program of rehabilitation, led by the World Bank. However, this debate has exceeded the boundaries of ecological interests. During the post-Soviet transition period and in a conflictual geopolitical context (blockades, breaks in energy supplies) and as the closing down of the Medzamor nuclear centre (which supplies the majority of the internal energy requirements) begins, how much weight do the environmental aspects and the rehabilitation of a lakeside system really carry when the future of the country as a whole is at stake ?, Les effets de la prédation d'un système lacustre durant plus de 30 années, à partir de 1930, au cours de l'époque soviétique, sont, aujourd'hui, au cœur de préoccupations à la fois économiques et environnementales. La gestion désastreuse du lac Sevan en Arménie a entraîné un abaissement de 20 mètres du niveau des eaux et a réduit d'autant le potentiel disponible. Les dégâts environnementaux ainsi occasionnés sont à l'origine, depuis l'indépendance, d'un vaste programme de réhabilitation mené avec l 'aide de la Banque Mondiale. Mais le débat dépasse le strict intérêt écologique. En cette période de transition post-soviétique, dans un contexte géopolitique conflictuel (blocus, rupture des approvisionnements énergétiques) et dans la perspective de la fermeture annoncée de la centrale nucléaire de Medzamor (assurant l'essentiel des besoins intérieurs en électricité), que pèsent les objectifs environnementaux et la réhabilitation d'un système lacustre alors que l'avenir même du pays est en jeu ?, Ardillier-Carras Françoise, Khoetsyan Ashot. Lac Sevan (Arménie) : des héritages soviétiques aux réalités d'aujourd'hui (Lake Sevan (Armenia) : from soviet heritage to present realities). In: Bulletin de l'Association de géographes français, 82e année, 2005-2 ( juin). Territoires ruraux centre-européens / Lacs, étangs et zones humides. pp. 199-212.

Yields of freshwater flowing into the Atlantic Ocean from West and Central Africa are computed from the data series of 33 rivers, between 1951 and 1989. It also takes into account water yields originating from coastal catchments, which represent 25 % of the water yield and 19 % of the 7.6 million square kilometers of total surface area studied. The total annual water yield to the Atlantic Ocean is about 2 700 billion cubic meters. During the period 1971–1989, total yield fell by 17.6 % as compared to the 1951–1970s average. Runoff deficit has been decreasing since 1951 in West Africa, but not in Central Africa.

This book, now in its second edition, addresses the diverse ways in which international law governs the uses, management, and protection of fresh water. The regulation of fresh water has primarily developed through the conclusion of treaties concerning international watercourses. Yet a number of other legal regimes also apply to the governance of fresh water. In particular, there has been an increasing recognition of the importance of fresh water to environmental protection. The development of international human rights law and international humanitarian law has also proven crucial for ensuring the sound and equitable management of this resource. In addition, the economic uses of fresh water feature prominently in the law applicable to watercourses and other sources of water, while water itself has become an important element of the trade and investment regimes. These bodies of rules and principles not only surface in an array of dispute settlement mechanisms, but also stimulate wider trends of institutionalization. The book investigates the origin and scope of these bodies of norms as they apply to fresh water, and demonstrates how they connect and adapt to one another, forming an integrated body of international principles. This approach is accompanied by a detailed analysis of the practice of states and of international organizations, taking into account the activities of the many non-state actors involved in the treatment of fresh water, and of the many jurisdictions which have been confronted with water issues.

Cet article examine la manière dont les risques résultant de l’interaction entre l’eau douce et l’eau marine sur un territoire hybride, situé entre terre et mer – le littoral – amènent à interroger les modalités de gestion des ressources naturelles et de l’environnement. Après avoir rappelé le caractère bidirectionnel des risques sur le littoral lorsqu’ils sont véhiculés par l’eau, nous analysons deux approches de gestion intégrée : la gestion intégrée des ressources en eau et la gestion intégrée des zones côtières. Tout en reconnaissant de nombreux points communs à ces deux approches, nous soulignons la nécessité de dépasser cette distinction qui tend à cloisonner des politiques qui mériteraient, au contraire, d’être envisagées de concert. Enfin, en nous appuyant sur l’exemple du territoire des Wateringues, situé dans la région Nord-Pas-de-Calais, nous illustrons les défis auxquels sont confrontées ces zones domestiquées par l’homme depuis plusieurs siècles, mais soumises à de multiples pressions et lieux de conflits d’usage que les risques peuvent parfois exacerber. This article deals with the way hazards, resulting from the interactions between fresh and marine waters in coastal zones, lead to question the variety of management practices of natural resources and the environment. In a first step, we underline the bidirectional character of hazards driven by fresh and marine waters in coastal areas. We discuss, in a second step, two way of dealing with integrated management of natural resources in those areas: namely Integrated Coastal Zone Management (ICZM) and the Integrated Water Resources Management (IWRM). While it is easy to recognize a convergence in the philosophy of such processes, we stress the necessity to go beyond distinctions, in order to build a more comprehensive approach. Finally, with the example of the Wateringues territory, located in the North of France, we illustrate the stakes of an integrated approach, in an area characterized by multiple pressures, where use conflicts are sometimes strengthened by the presence of hazards.

This study is a first attempt to investigate the impact of urban contamination on metal tolerance of heterotrophic river biofilms using a short-term test based on beta-glucosidase activity. Tolerance levels to Cu, Cd, Zn, Ni and Pb were evaluated for biofilms collected at three sites along an urban gradient in the Seine river (France). Metallic pollution increased along the river, but concentrations remained low compared to environmental quality standards. Biofilm metal tolerance increased downstream from the urban area. Multivariate analysis confirmed the correlation between tolerance and contamination and between multi-metallic and physico-chemical gradients. Therefore, tolerance levels have to be interpreted in relation to the whole chemical and physical characteristics and not solely metal exposure. We conclude that community tolerance is a sensitive biological response to urban pressure and that mixtures of contaminants at levels lower than quality standards might have a significant impact on periphytic communities. (C) 2011 Elsevier Ltd. All rights reserved.

We examined the spatial and temporal variation of species diversity and genetic diversity in a metacommunity comprising 16 species of freshwater gastropods. We monitored species abundance at five localities of the Ain river floodplain in southeastern France, over a period of four years. Using 190 AFLP loci, we monitored the genetic diversity of Radix balthica, one of the most abundant gastropod species of the metacommunity, twice during that period. An exceptionally intense drought occurred during the last two years and differentially affected the study sites. This allowed us to test the effect of natural disturbances on changes in both genetic and species diversity. Overall, local (alpha) diversity declined as reflected by lower values of gene diversity H(S) and evenness. In parallel, the among-sites (beta) diversity increased at both the genetic (F(ST)) and species (F(STC)) levels. These results suggest that disturbances can lead to similar changes in genetic and community structure through the combined effects of selective and neutral processes.

International audience; Sexual maturation in sea trout (Salmo lrutlo L.) running up the River Calonne (Normandy, France), at the finnock stage, is characterized. Autopsy of I18 finnock in summer showed that 87 ± 7 % aged 2+ and 33 ± 15% aged 1 + were undergoing gametogenesis. In autumn all the fish were maturing. The analysis of plasma levels of 11-ketotestosterone, 17β-0estradiol, maturational gonadotropin and vitellogenin showed that only females in vitellogenesis can be well identified in summer (plasma vitellogenin greater than 0.30 mg ml-1). The morphological recognition of females among 134 autumn finnock and the ELISA assay of plasma vitellogenin of 814 summer finnock, demonstrated that vitellogenic females represented 12 ±2%0 of the 1 + individuals and 46 ± 2% of 2+ fish captured during the 1985 run. The question of a possible relationship between the salinity tolerance ofjuvenile trout migrating towards the sea in the spring and their age on first migration in the river is discussed.

The reproduction strategy of the Palaemonid shrimp, #Macrobrachium Amazonicum$, has been studied on Careiro Island in a floodplain lake in Central Amazonia. Ovigerous females have been observed all year round. Howether, three periods of the hydrological cycle were significantly more favourable to gonad ripening : the middle of the rising and of the falling of the water level, as well as the low level. This suggests the direct effect of two factors : the current velocity and the phytoplankton production. At the population level, the maximum reproduction velocity has been observed during low waters, and during rising waters. This strategy increases the survival of planktonic larvae during the highest phytoplankton production period, and reduces the intraspecific competition, increasing the larval dispersion in the floodplain. In the lake, the percentage of ovigerous females was always higher regardless of size class of the adult prawns and of season, than in the channels or in the river, suggesting that the lacustrine environment is the more favourable to #M. amazonicum$ reproduction. In Eastern Amazonia, #M. amazonicum$ shows a typical reproduction pattern of littoral Palaemonids : mass spawning occurs during the falling water, increasing the larval dispersion towards the estuary. The reproduction flexibility of #M. amazonicum$ explains its success in colonizing a variety of environments in a wide geographical range in South America. (Résumé d'auteur)

The precise number of extant fish species remains to be determined. About 28,900 species were listed in FishBase in 2005, but some experts feel that the final total may be considerably higher. Freshwater fishes comprise until now almost 13,000 species (and 2,513 genera) (including only freshwater and strictly peripheral species), or about 15,000 if all species occurring from fresh to brackishwaters are included. Noteworthy is the fact that the estimated 13,000 strictly freshwater fish species live in lakes and rivers that cover only 1% of the earth’s surface, while the remaining 16,000 species live in salt water covering a full 70%. While freshwater species belong to some 170 families (or 207 if peripheral species are also considered), the bulk of species occur in a relatively few groups: the Characiformes, Cypriniformes, Siluriformes, and Gymnotiformes, the Perciformes (noteably the family Cichlidae), and the Cyprinodontiformes. Biogeographically the distribution of strictly freshwater species and genera are, respectively 4,035 species (705 genera) in the Neotropical region, 2,938 (390 genera) in the Afrotropical, 2,345 (440 genera) in the Oriental, 1,844 (380 genera) in the Palaearctic, 1,411 (298 genera) in the Nearctic, and 261 (94 genera) in the Australian. For each continent, the main characteristics of the ichthyofauna are briefly outlined. At this continental scale, ichthyologists have also attempted to identify ichthyological ‘‘provinces’’ that are regions with a distinctive evolutionary history and hence more or less characteristic biota at the species level. Ichthyoregions are currently identified in each continent, except for Asia. An exceptionally high faunal diversity occurs in ancient lakes, where one of the most noteworthy features is the existence of radiations of species that apparently result from intra-lacustrine speciation. Numerous fish-species flocks have been identified in various ancient lakes that are exceptional natural sites for the study of speciation. The major threats to fish biodiversity are intense and have been relatively well documented: overexploitation, flow modification, destruction of habitats, invasion by exotic species, pollution including the worldwide phenomena of eutrophication and sedimentation, all of which are interacting.

In Bossio, Deborah; Geheb, Kim (Eds.). Conserving land, protecting water. Wallingford, UK: CABI; Colombo, Sri Lanka: International Water Management Institute (IWMI); Colombo, Sri Lanka: CGIAR Challenge Program on Water & FoodComprehensive Assessment of Water Management in Agriculture Series 6

Onchocerciasis is a widespread disease in intertropical Africa, which, ultimately, causes irreversible blindness. The disease is transmitted by a small blackfly, Simulium damnosum (Diptera), which has aquatic larval and pupal stages. The breeding sites of the blackflies are riffles. These river reaches are the targets of the control campaign of the Onchocerciasis Control Programme in West Africa (OCP). An aquatic monitoring network covering the totality of the area exposed to the insecticide was set up to evaluate environmental impact. In this paper, we present results from the OCP 20-year period of monitoring of the ichthyofauna regularly exposed to larvicides. We do not record any measurable effects of pesticides on the CPUE, abundance of species, trophic structure, community structure or fish health. However, we detect the emergence of a number of medium-term tendencies. These tendencies may relate to climatic conditions that have a consequent effect on hydrology. Thus, we note a constant decrease in the CPUE from the beginning of the monitoring until 1995. The rivers were treated during that time until 1990 or 1993, depending on the station. But even after the treatments ended, the number of catches continued to decrease. As a result, we consider other factors to be the cause of that decline. The average level of annual discharges in this region has been decreasing regularly from the beginning of the 1970s. The production of fish fluctuates in all the rivers according to the flood rate. Important floods inundate larger areas, making greater quantifies of food available, and thus improving the conditions for reproduction. The determining factor of the ichthyological stock abundance seems to depend both on the extern and the duration of the flood. In our catches, the observed effect was not immediately evident but appeared a few years later as a cumulative effect of poor hydrological conditions. An increase in the CPUE since 1996 has been related to improved hydrological conditions. In these last few years, we have observed an intensification of the basic flow leading to a ground water renewal. Furthermore, on three of the stations investigated, it appeared that the impediment of rivers (dams) could induce different and/or antagonistic effects. In some cases, we have observed that in spite of unfavourable hydrological conditions, certain species appear to be favoured by the presence of the dam. But, the damming of the river has a negative effect on other species, particularly on the coefficient of condition of migratory fishes. The impact of these factors is enhanced by the fact they exist conjointly. © 1999 Ifremer/Cnrs/Inra/Ird/Cemagref/Éditions scientifiques et médicales Elsevier SAS Résumé — Maladie largement répandue en Afrique intertropicale l’onchocercose est un fléau qui provoque, à son stade ultime, une cécité irréversible. La maladie est transmise par un petit Diptère, Simulium damnosum, qui présente une phase larvaire et nymphale aquatique. Ce sont les gîtes larvaires de ce vecteur, biefs à courant rapide des rivières, que le Programme de lutte contre l’onchocercose en Afrique de l’Ouest (OCP: Onchocerciasis Control Programme in West Africa) traite lors de ses campagnes de lutte. Comme toute lutte insecticide, OCP représentait une menace importante pour l’environnement. C’est pourquoi le programme s’est doté d’un réseau de surveillance des écosystèmes aquatiques, couvrant l’ensemble de la zone exposée aux épandages d’insecticides. Ce sont les résultats de vingt années de surveillance de l’ichtyofaune, régulièrement exposée aux traitements larvicides, qui sont présentés ici. Les différentes variables étudiées dans cette étude, ne permettent pas de mettre en évidence un effet décelable des pesticides sur la structure et la richesse spécifique des peuplements. De même, la composition trophique ou la santé des poissons ne semblent pas affectées. Cependant, nous observons parfois certaines tendances, à moyen terme, qui semblent être essentiellement sous l’influence des conditions climatiques, probablement hydrologiques. Ainsi, nous observons une diminution régulière des prises par unité d’effort (PUE) du début de la surveillance jusque vers 1995. Durant cette période, les rivières ont été, selon les stations, traitées jusque 1990 ou 1993. Mais, alors que les traitements étaient terminés, la diminution des captures s’est poursuivie. Nous pouvons donc estimer que d’autres facteurs en sont la cause. Si nous considérons les crues moyennes annuelles et régionales, nous observons une diminution régulière depuis le début des années 1970. Dans toutes les rivières, la production de poisson fluctue en fonction du régime d’inondation. Lorsque les crues sont favorables, elles inondent des superficies plus grandes, ce qui favorise la disponibilité en nourriture, et améliore donc les conditions pour la pérennité des espèces. En fait, le facteur déterminant de la production halieutique semble être lié à la fois à l’étendue et à la durabilité de l’inondation. Dans nos captures, l'effet apparaît avec quelques années de retard comme s’il y avait eu un effet cumulatif des mauvaises conditions hydrologiques. Inversement, l’accroissement des PUE depuis 1996 paraît bien corrélé aux meilleures conditions de crue observées. Ces dernières années, nous notons un renforcement de l’écoulement de base qui se traduit par une recharge des nappes phréatiques. Enfin, sur trois stations étudiées, les barrages peuvent induite différents effets, antagonistes ou non. Dans certains cas, nous observons qu’en dépit de mauvaises conditions hydrologiques, certaines espèces semblent être favorisées par le barrage et sa retenue d’eau. Inversement, le barrage du fleuve peut avoir un effet négatif sur certaines autres espèces, particulièrement sur celles qui effectuent des migrations longitudinales. Tous ces facteurs semblent montrer une pression d’autant plus importante qu’ils se produisent en synergie. © 1999 Ifremer/Cnrs/Inra/Ird/Cemagref/Éditions scientifiques et médicales Elsevier SAS

Compared to the sea, freshwaters are deficient in major taxa and there are no uniquely freshwater metazoan phyla (May, 1994). In river lakes, aquatic biota is similar to the biota of the river basin. The great majority of existing isolated lakes (around 10,000 exceeding 1 km 2 in extent) are geologically very young and their flora and fauna are usually depauperate compared to ancient lakes that exhibit a rich endemic fauna for several major groups of animals. Species flocks for fish and invertebrates are known from ancient lakes and represent a unique biological heritage to be preserved. Major threats to the lakes biota include habitat alteration, fisheries practice, pollution, and the introduction of exotic species.

Le phytoplancton a été étudié dans deux mares (Llanta et Perdida) et dans un marais (Choui) sur des îles du rio Parana (27° 30°S, 58° 55 O). Des échantillons ont été prélevés dans la végétation des rives et dans les eaux libres en période de crue et d'étiage entre décembre 1981 et février 1983. La densité et la diversité spécifique ont été analysées en fonction des variables de l'environnement. En période d'étiage, la diversité la plus faible et la densité la plus forte (7706 ind/ml) ont été trouvées dans le marais à #Panicum grumosum$, avec dominance de l'Euglénophycée #Trachelomonas volvocina$. Dans les mares, les plus fortes densités ont été relevées dans la mare Llanta dans les zones à #Eichhornia azurea$ et #Salvinia sp.$, et dans la mare Perdida, dans les herbiers à #Polygonum acuminatum$

International audience; Juvenile coho salmon, Oncorhynchus kisutch, adapted to fresh water or seawater were either acutely handled or continuously stressed by severe confinement. Chronic stress, independent of external salinity, caused a gradual increase in the concentration of circulating prolactin that persisted for 1 to 5 days but lagged behind the cortisol response which peaked much more rapidly and remained elevated. Acutely stressed fish showed a rapid, more transient increase in plasma cortisol titer with no apparent effect on prolactin. Confinement appeared to be more stressful to fish in salt water than to those in fresh water, as judged by their sodium regulatory ability, hormone profiles, and mortality. Stress always elevated plasma prolactin concentrations, regardless of medium or developmental stage.

La colonisation de #Polygonum acuminatum$ et de #Panicum elephantipes$ en décomposition a été étudié dans un bras secondaire du Rio Parana qui pénètre dans l'île de Choui. La perte en poids sec a été suivie sous deux mètres d'eau par la technique du sac en filet. L'abondance des invertébrés qui ont colonisé le substrat a été exprimée par sac et par g de poids sec. La décomposition calculée sur 50 jours a été respectivement de 0,017 j-1 pour #P. acuminatum$ et de 0,085 j-1 pour #P. elephantipes$. La densité des invertébrés a augmenté au fur et à mesure de la décomposition, avec une corrélation négative entre le poids sec restant de litière et le nombre d'invertébrés par g de litière. Une diminution de la densité a été observée après 24 jours d'incubation lors de la crue du Parana qui a envahi l'île de Choui. Les collecteurs et les prédateurs ont été trouvés en densités égales pendant les 7 premiers jours pour les deux substrats; avec une dominance de #Chironomus$ sp. #Dicrotendipes$ sp. et #Ablabesmyia$ sp. Les filtreurs ont été dominants après 30 jours d'incubation (#Cyclestheria hislopii$ et #Cytheridella ilosvayi$). (Résumé d'auteur)

The effects of salinity were investigated in the black-chinned tilapia Sarotherodon melanotheron heudelotii originating from a hypersaline estuary (Saloum, Senegal). Under controlled conditions, juvenile fish originally kept in freshwater (FW) were divided into two groups exposed to FW or directly to 35 psu seawater (SW). Part of these SW fish were then acclimatised to hypersalinewaters (HW) by a step-wise increase of 7 psu/day up to 70 (HW70) and 90 (HW90). Three major ion transporters, Na+/K+-ATPase, the cotransporter Na+/ K+/2Cl- (NKCC) and the Cl- channel (CFTR) were localized by immunofluorescence in the gill ionocytes and changes regarding ionocytes localization, number and sizes were investigated. In FW, Na+/K+-ATPase immunostained ionocytes were only observed at the base of the filaments, whereas in SW and HW they were localized on both the filaments and the lamellae suggesting that lamellar ionocytes could also be functional in SW. A significant increase in ionocyte number and size (area) occurred following transfer from FW to HW. Although the cell number remained constant between HW70 and HW90, their size increased from FW to HW90, indicating that the size and shape of cells could be a sensitive indicator of osmoregulation in HWin this tilapia. In FW, NKCC stainingwas concentrated at the apical region and CFTR was not observed. In SW, Na+/K+-ATPase and the cotransporter NKCC were colocalized on the basolateral membrane, while CFTR was located at the apical region. (Resume d'auteur)

National audience

1. 1. In sea-water, adult salmon ( S. salar ) exchange an average of 12.6% of total body sodium/hr. 2. 2. Following transfer to fresh water sodium uptake follows Michaelis-Menton kinetics. F max = 2.40 mmol Na/1 ECF/hr, K m = 0.26 mmol Na/1. The uptake system is fully activated immediately following transfer to fresh water. 3. 3. Post smolts adapted to sea-water for 3 months take up sodium at only one third of the rate of adult fish following return to fresh water. 4. 4. The concentration of prolactin in the plasma is low in sea-water adapted fish and does not rise during the first 8 hr in fresh water. 5. 5. At pH 5 sodium uptake is reduced by almost 90%, even in the absence of aluminium, but recovers immediately on return to neutral water. 6. 6. At pH 5 and 20 μmol Al/1 there is little further effect on sodium uptake but after 6 hr in aluminium the inhibition of sodium uptake continues after return to neutral aluminium fresh water and uptake is only 50% of normal 24 hr later.

Dans les milieux peu profonds, la contribution du périphyton à l'apport global de matière organique est en général importante. La présente étude à permis d'estimer la production du périphyton à 14 g de matière organique par mètre carré au cours de la période d'inondation (juin à janvier). La biomasse maximale du périphyton ne coïncide pas avec la biomasse maximale de son substrat, #Hymenachne amplexicaulis$. L'ombre créée par le substrat peut être la cause de ce décalage. La mesure de la production primaire a été faite par la méthode de l'oxygène, avec flacons clairs et flacons obscurs, suivant deux techniques. Dans la première, le périphyton était détaché de son substrat naturel juste avant l'incubation. Dans ce cas la production mesurée était, en moyenne, de 4,1 mg O2/100 cm2 de substrat ou 1,0 mg O2/mg de périphyton. Dans la deuxième technique, le périphyton ayant poussé sur des tiges de PVC était incubé intact. Dans ce cas, la production mesurée était inférieure : 2,O mg O2/100 cm2 de substrat ou O,10 mg O2/mg de périphyton. La différence est attribuée à la perturbation causée par l'arrachage du périphyton de son substrat naturel. La sensibilité du périphyton à de telles manipulations plaide en faveur de mesures sur la communauté intacte liée à un substrat artificiel difficilement manipulable. (Résumé d'auteur)

Cette note compare les habitudes alimentaires de trois espèces de poissons gymnotiformes de la famille Apteronotidae. Ces poissons s'alimentent de stades immatures aquatiques d'insectes. Ceux-ci habitent des galeries creusées dans le substrat argileux du fond. Parfois ce substrat se détache et forme des nodules qui sont transportés par le fleuve. Les données suggèrent l'existence d'une relation entre la morphologie buccale du poisson et le type d'insecte aquatique dominant dans son régime. Elle provient du fait que chaque espèce d'insecte vit dans un trou de taille et forme distinctes. (Résumé d'auteur)

La relation entre l'origine et l'évolution de ces lacs et leur comportement hydrologique est discutée. Dans les cours d'eau et les lagunes on a distingué des connections directes et indirectes. Le système de communication avec le Parana, évolue dans ces lacs en quatre phases hydrologiques : phase d'isolement, phase de crue dans le lit mineur, phase de débordement et phase de décrue dans le lit mineur. Ce mélange annuel entre les eaux courantes et les eaux dormantes, constitue le principal facteur de l'évolution et du comportement physique, chimique et biologique de ces plans d'eau. (Résumé d'auteur)

La fauna bentica de los principales cuerpos de agua del Altiplano boliviano y de la Cordillera adyacente era conocida solamente a traves de algunos muestreos hechos por expediciones itinerantes. En el marco de un estudio mas completos concerniente a la distribucion cualitativa y cuantitativa de esta fauna, se estudio su evolucion en el curso de un ciclo hidrologico anual y de esta forma, diferentes medios acuaticos han podido ser estudiados de manera regular. El lago pequeno Titicaca, asi como el lago grande son caracterizados por poblaciones particulares, en tres biotopos diferentes. De manera general la fauna bentica puede ser muy abundante en ciertas estaciones del ano (y pero es tambien) muy poca diversificada. Ademas de una composicion diferente, la misma conclusion se aplica a las comunidades de los lagos de altura. La fauna bentica de los rios de la Cordillera parece muy estable durante todo el ano en las zonas donde el caudal cambia poco y la diversidad faunistica aumenta cuando disminuye la altura

Les échantillons ont été prélevés de janvier 1982 à janvier 1983 dans les franges à #Panicum grumosum$ et à #Polygonum acuminatum$ des îles Palomera et Choui, qui sont situées sur le Parana à 45 km en aval de sa confluence avec le Paraguay. Durant la période d'étude, des périodes de hautes et de basses eaux ont été observées, y compris une crue exceptionnelle au cours des derniers mois. En période de basses eaux, les invertébrés associés à la végétation suivent une distribution d'abondance log-normale, avec une forte densité et une diversité de 3,81 bits. Les Copépodes, Cladocères, Oligochètes, et Ostracodes forment les groupes les plus abondants. Lors des périodes prolongées de forte crue, l'abondance et la diversité diminuent, et la distribution est du type géométrique. Durant les crues de plus faible durée, la distribution d'abondance relative est semblable à celle des basses eaux. (Résumé d'auteur)

On a étudié pour la première fois la faune des rotifères de 51 milieux aquatiques des provinces de Santiago del Estero, Tucuman, Catamarca et La Rioja (rivières, ruisseaux, barrages, mares, lagunes). On a identifié un total de 84 taxons. L'affinité taxonomique entre milieux est très basse. Les différences dans la composition de la faune de différents milieux sont mises en relation avec la salinité de l'eau. #Colurella colurus, Lecane obtusa, L. punctata, L. thalera, L. crepida, Trichocerca elongata braziliensis$ sont des espèces nouvelles pour l'Argentine. Le statut spécifique de #L. thalera$ est discuté. De nouvelles variations morphologiques de celle-ci et de #Keratella procurva$ (Thorpe) sont décrites. On étudie aussi le statut de #L. punctata$ et la validité taxonomique de #L. harringi$. (Résumé d'auteur)

L'objectif de cette étude est d'estimer le potentiel d'ICESat pour la surveillance des eaux continentales à travers les cas du lac Léman (Suisse et France) et des rivières de la France métropolitaine. / The Ice, Cloud and Land Elevation Satellite (ICESat) laser altimetry mission from 2003 to 2008 provided an important dataset for elevation measurements. The quality of GLAS/ICESat (Geoscience Laser Altimeter System) data was investigated for Lake Leman in Switzerland and France by comparing laser data to hydrological gauge water levels. The correction of GLAS/ICESat waveform saturation successfully improved the quality of water elevation data. First, the ICESat elevations and waveforms corresponding to water footprints across the transition from the land to water were analyzed. Water elevations (2 to 10 measurements) following the land-water transition are often of lesser quality. The computed accuracy for the ICESat elevation measurements is approximately 5 cm, excluding transitions footprints, and 15 cm, including these footprints. Second, the accuracy of ICESat elevation was studied using data acquired on French rivers with a width greater than the size of the ICESat footprint. The obtained root mean square error (RMSE) for ICESat elevations in regard to French rivers was 1.14 m (bias = 0.07 m; standard deviation = 1.15 m), which indicates that small rivers could not be monitored using ICESat with acceptable accuracy due to land-water transition sensor inertia.

Ce travail a été réalisé dans le cadre du projet shad'eau visant à étudier les causes de déclin des populations d'aloses du sud-ouestde la France. Ce guide est le premier réalisé sur l’identification du zooplancton et des invertébrés présents dans les rivières artificielles del’installation expérimentale de Saint-Seurin-Sur-L’Isle de l’UR-EABX (INRAE Gazinet, 33) et dans les contenus stomacaux de juvéniles de grandes aloses (Alosa alosa). Ce guide a pour objet d’aider les futurs observateurs néophytes dans leurs identifications. Il a été réalisé à partir des observationset photos d’Adrien Aries, réalisées au cours de son stage de maîtrise 2ème année (Aries 2019) « Caractérisation du milieu trophique, étude du régime et des préférences alimentaires des juvéniles de grande alose (Alosa alosa) en rivières artificielles ». Ces observations ont été effectuées à l’aide d’une loupe binoculaire Olympus SZX12 au laboratoire d’hydrobiologie de l’INRAE deGazinet. Les photos et dimensions ont été réalisées grâce au logiciel Archimed (Microvison Instruments 2014). Il s’agissait initialement de déterminer les grands catégories d’individus se développant ou étant présent dans les rivièresartificielles et dans les contenus stomacaux d’aloses. Les chapitres ont été réalisés par regroupement des grandes catégories, les individus les plus fréquemment rencontrés sont présentés dans les premiers chapitres (Cladocères, Diptères, Copépodes, Ostracodes). Il faut noter que les plus petits individus n’ont peut-être pas été décelés lors de ces observations tels que desprotozoaires et des petits métazoaires (exemple : rotifères). Sur chaque photo est indiqué si il s’agit d’observation réalisée sur des échantillons d’eau (noté : zooplancton ou phytoplancton) ou du contenu stomacal des aloses (noté : contenu stomacal) afin d’avoir un référence sur la conservation des individus après ingestion par les juvéniles d’aloses. Le futur observateur devra se reporter sur des ouvrages spécifiques à chaque groupe pour réaliser une détermination plus poussée si cela s’avère nécessaire. Dans ce guide, une liste non exhaustive d’ouvrages et de sites internet a été fournie pour certains groupes biologiques afin d’aider le futur observateur.

National audience; Benthic diatoms are routinely used to assess river pollution. Most of the tools are using pollution sensitivities of diatom species. Determination of diatom species requires a long and regular practice because its flora is extremely diverse. Moreover morphological features to separate numerous taxa are scarce. The choice of taxonomic resolution is very rarely asked for diatom bioassessment. The objective of this study was to test on a database the impact of taxonomic resolution on information loss. Our final datasets, gathering about 2000 diatom samplings carried out in the framework of Biomonitoring rivers in the Rhone-Mediterranean and Rhine-Meuse basins, combined 3 kinds of tables: (a) taxa abundance by site arrays on the species, genus, family, order, class and sub-division; (b) physical and chemical site characterization; (c) site typology. Based on Mantel tests, it appeared that all the arrays were significantly correlated (except for subdivision). They were even very highly correlated from species to class resolutions. Canonical correspondence analyses showed that based on chemical parameters (nutrient, organic matter and mineralization) the highest percentage of variability in the diatom community matrix that could potentially be explained was met for the order level. The poorest were met for sub-division and species resolutions. Finally, based on Corrected Rand Indexes, we observed that the more precise the taxonomic resolution we have the more correlated to the hydro-ecoregional classification we got. These results lead to wonder if a very fine taxonomic resolution is necessary to assess classical pollution (nutrient, organic matter). Hypotheses to explain such results are that (1) many species are too rare to establish their ecological requirements with certainty (2) more environmental descriptors are necessary to explain presence of some species (3) the dataset is surely marred by identification errors especially at species level. On the other hand it seems important to keep a species level identification to know the ecoregional membership of the diatom community.

The aim of this chapter is to introduce the main topics in the Mediterranean circulation research and to give a general description of the Mediterranean Sea variability. Its scope is to provide information that is important for a comprehensive view of the most relevant issues concerning climate, which is a coupling between atmosphere and sea. The chapter describes data, research results, and key findings that have been reported in the most recent literature about the Mediterranean Sea circulation. The issue about sea level is considered in Chapter 4. The chapter also includes, in its concluding section, a discussion of the main open issues in Mediterranean Sea research.