Bien que ne faisant pas partie des radionucléides à vie longue, le zinc 65 représente un polluant radioactif important de par sa présence dans les effluents liquides de certaines installations nucléaires et de son isotopie avec un oligo-élément biologique essentiel. Dans ce travail l'auteur aborde le problème du transfert et de la concentration de ce radionucléide dans les chaînes alimentaires aquatiques.

L'absorption par des anguilles de zinc 65 contenu dans de la nourriture naturelle se traduit, après l'ingestion de 11 repas échelonnés sur 69 jours, par une accumulation du radionucléide correspondant à un taux de rétention moyen de 22 %. Environ 45 % du zinc 65 sont éliminés avec les fèces ce qui représente près de 60 % de l'excrétion totale. Entre deux repas successifs on observe une élimination rapide du zinc 65 qui correspond à 2 périodes biologiques courtes, Tb1 ~ 1 jour et Tb2 ~ 4,5 jours. Après l'arrêt de l'ingestion de la nourriture contaminée le radionucléide accumulé n'est que très lentement éliminé (Tb3 ~ 450 jours) et l'excrétion fécale devient très nettement prépondérante ( ~ 80 %). L'organotropisme du zinc 65 se caractérise par une concentration élevée dans les viscères et, en ce qui concerne la distribution, par une forte prédominance du tissu musculaire.

Seasonal dynamics of zooplankton were investigated in three different habitats of the shallow and temperate Kačležský pond (Czech Republic) during 2003–2004. The studied habitats included the limnetic zone and two littoral zones, each dominated by a different type of emergent macrophyte, reed grass (Glyceria maxima) and common reed (Phragmites australis). Species richness (calculated as number of taxa) was higher in both littoral zones than in the limnetic zone. The seasonal development of limnetic and littoral zooplankton communities differed. In contrast to the two littoral zones, close correlation with chlorophyll-a concentration was found for rotifers and cladocerans in the limnetic zone. Moreover, cladocerans inhabiting littoral areas (mainly Bosmina longirostris) reached annual maxima during spring when chlorophyll-a concentrations were low.

Temperate streams flowing through deciduous forests derive most of their energy and carbon from allochthonous organic matter supplied by the riparian vegetation mostly during the autumnal litter fall. The decomposition of this coarse particulate organic matter (CPOM) supports the aquatic foodwebs throughout the year. During the decomposition process, part of the CPOM is converted into fine particulate organic matter (FPOM). In this study, we assessed the relationships among decomposition rates of a dominant litter species, oak leaf litter (estimated by the litter bag approach in the presence and absence of macroinvertebrates), benthic CPOM stock and FPOM flux over 12 months in a temperate mountain oligotrophic stream. We also assessed the relationship between these organic matter variables and environmental variables over the same period. As expected from the seasonality in temperature, litter decomposition rates varied over the year and were positively correlated with water temperature and dissolved phosphorus concentration. However, benthic CPOM stock did not significantly change over the year; the higher rainfall in winter and the higher litter decomposition in spring might have compensated for each other in keeping the CPOM stock fairly constant year round. FPOM flux was positively correlated with litter decomposition rates as expected, and this relationship was primarily driven by the activities of detritivores and not of microbes. We can anticipate changes in the carbon cycle, both locally and downstream, if oligotrophic montane streams are subjected to temperature increases (e.g., due to removal of riparian vegetation or in a global warming scenario) and nutrient enrichment from effluents or agricultural activities.

Benthic macroinvertebrates are considered as a representative taxon that indicates the ecological status of freshwater ecosystems. Numerous indices derived from community data have been proposed to estimate either biological water quality or ecosystem health. In this study, metrics based on benthic macroinvertebrates at the family level were screened using ecological informatics to provide a multi-metric measurement that would be suitable for presenting ecological integrity across different levels of environmental impact. Benthic macroinvertebrates were collected at a total of 720 sample sites from river basins and streams in Korea in 2009. Based on four categories of community status (i.e., diversity, richness, tolerance, and composition), 37 metrics were selected as initial candidates according to the literature. The candidate metrics were evaluated according to parameters including discriminatory power, redundancy, and responsiveness to stressors. Self-organizing map was utilized to assist the screening procedure by providing ordination, clustering, and visualization of metric and environmental data. Six metrics were finally selected as a multi-metric and were compared with conventional indicators for presenting the ecological integrity of streams.

Leaves of two species, alder (Alnus glutinosa) and holm-oak (Quercus ilex), were exposed in bags of two mesh sizes in two climatically contrasting sites of a Corsican softwater stream. Leaves were incubated both in winter and in summer for about 6 months. The field experiment was designed to determine the influence of both spatial (climate) and temporal (season) variations of temperature, as well as differences in the chemical and physical properties of sclerophyllous and malacophyllous leaves, on leaf decomposition rates. Comparisons were made between leaves colonized by macroinvertebrates and leaves protected by finemesh. In winter and summer, holm-oak leaves were colonized much less by macroinvertebrates than alder leaves. Spatial and temporal differences in leaf litter processing were mainly dependent on three factors (i) the chemical and physical properties of the leaves, (ii) the abundance of macroinvertebrates in the sediment and (iii) the temperature. The climatical pattern of temperature had a greater influence than its seasonal pattern. In contrast with many other studies, abiotic factors dominated over biotic factors in this study.

Pour D. gonocephala, les limites de survie indéfinie à température constante et en eau agitée sont voisines de 20-21° C. Par sa résistance thermique comme par sa répartition dans la nature, cette espèce se montre remarquablement intermédiaire entre Polycelis felina et Polycelis nigra.

Une étude typologique est effectuée sur la Loue, grand cours d'eau à Salmonidés du massif du Jura, à l'aide de la méthode d'analyse factorielle des correspondances.

Cette méthode est appliquée à l'analyse des variations longitudinales de 18 composantes physico-chimiques et de la distribution de 135 espèces de Poissons (18 espèces), Plécoptères (27 espèces), Éphéméroptères (33 espèces) et Trichoptères (57 espèces) sur 18 stations jalonnant les 126 km du cours d'eau.

Les structures biologiques sont déterminées séparément pour chaque ordre puis pour l'ensemble de la faune étudiée ; 4 groupements et 12 noyaux d'affinités écologiques sont mis en évidence.

L'analyse mésologique fait apparaître une participation hiérarchisée des paramètres mais aussi l'absence d'une structure abiotique nette soulignant le caractère intégrateur des espèces et faisant appel à la notion de « complexes paramétriques équivalents ».

Les résultats obtenus au niveau des espèces, du cours d'eau lui-même et des paramètres physico-chimiques sont commentés puis confrontés ; l'intérêt de la recherche typologique est alors mis en évidence parallèlement au caractère essentiellement relatif du déterminisme des espèces et de leurs groupements.

Three males of Cryptocandona vavrai were discovered in geographically distant sites (UK, France, Romania), representingdifferent environments (surface and underground waters). The species may be considered a parthenogen with rare occurrence ofsingle males, the morphology of which was hitherto poorly known. The first complete description of males is given, which, togetherwith comparative descriptions of females from surface waters at the UK site and underground waters at an additional sitein eastern France, as well as consideration of the shape and size of the last juvenile stages, permits the presentation of a morecomplete description and an amended diagnosis of the species. Cryptocandona vavrai takes an intermediate position in thegenus, lodged between stygobitic species and the cluster of more primitive C. reducta and C. brehmi. Due to a number of traits(broad calcified inner lamella of the valves, 3rd ramus podomere of the antennule lacking the posterior seta, hook-like shortestterminal seta of the cleaning leg, specific morphology of the male prehensile palps and hemipenis lobes) C. vavrai is fairly easilyrecognised, although there seems to be considerable intraspecific variation. The comparison between females from surfaceand underground waters revealed substantial elongation of the apical antennal claws, aesthetascs and the distal claw of the walkingleg in the latter population. The major difference recorded among the compared males is the underdevelopment of the externalclaw z2 on the 3rd endopodial podomere of the antenna in the male from the underground waters in Romania. The revealedvariation could indicate that some populations may deserve a separate (sub-specific) taxonomic status. Finally, available data onthe distribution and ecology of this species are summarised.

A limnological study was performed out, over 8 years from 1979 to 1986, in a shallow recently created sand-pit lake,Lake Créteil (Paris suburb, France). The lake is mainly supplied by phreatic waters. Typical of shallow waters, thermal stratification which occurred from May to October was intermittently broken by wind, leading to high seasonal fluctuations and allowing a reoxygenation of the total water column. The interannual development of the lake was characterized by a regular increase in transparency (from 1 m in 1979 to 2.7 m in 1985) which was partly due to not only stabilization of the bottom sediment and the banks, but also to a reduction of the biological component. A decrease in chlorophyll a concentrations resulted from nutrient diversion of domestic inputs collected through the rainwater pipe cominginto the lake. The rapid restoration of water quality shows that this small artificial lake is very sensitive to human interventions.

Des expérimentations de terrain en parcelles limitées ont permis, à partir de piégeages d'adultes, d'évaluer l'impactde huit insecticides sur des populations larvaires composées de 82 % de Chironomus salinarius, de 12 % de Chironomushalophilus et de Chironomus plumosus et 6 % d'autres espèces non identifées. Le diflubenzuron et les toxines de Bacillus thuringiensis H 14 et Bacillus sphaericus n'ont pas d'effet marqué aux doses détruisant les larves de moustiques. A ces mêmes doses, le fénitrothion, le téméphos et la deltaméthrine limitent fortement l'émergence. Le chlorpyrifos et le S 31183 (juvénoïde Sumitomo) sont très toxiques.

Escherichia coli is an indicator of fecal pollution used to mandate recreational and drinking water quality. Concentrations of culturable E. coli following contamination of surface water are determined by three factors: dilution; cell attachment to particulate material and settling or resuspension in the water column; and the net rate of change in viability. This study evaluated the variability in the latter parameter, and how predictive variation in death rate was of culturable population densities at the time of sampling. Water samples (N=232) with varying levels of E. coli contamination were collected from 46 discrete locations in four watersheds across Canada over a three-month period and enumerated for culturable E. coli by membrane filtration plate counting (T0EC). Water samples were again enumerated following a laboratory 24 h holding period at 30°C in the dark, and the difference considered the death rate (ΔEC). Relationships of T0EC and ΔEC with environmental and water chemistry factors were explored using step-wise multiple regression. The model predicting T0EC indicated that stream order, total rainfall seven days in advance of sampling day, total phosphorus, and ΔEC were the most significant contributors. The model predicting ΔEC indicated that turbidity and NH3+NH4 were the most important contributors. A model suggests that the persistence factor is less important than dilution (i.e. stream order) in describing E. coli densities, followed by factors that influence the loading of E. coli into watersheds.

Répartition géographique comparée des trois espèces de Rhithrogena du groupe germanica sensu stricto de l'Ouest del'Europe et de l'Afrique du Nord. Redescription de l'holotype de Rh. soteria Navás, 1917 (imago male, terra typica : l'Espagne) et description de Rh. ryszardi n. sp. (imago male) provenant du Moyen Atlas. Cette dernière est nettement moins orophile que les trois autres espèces de ce genre déjà signalées du Maroc.

Le taux de croissance de Scenedesmus crassus est décrit en fonction de l'intensité lumineuse. Différentes expressions de cette fonction sont testées. Les paramètres de l'équation résultante sont alors exprimés en fonction de la température. La comparaison des taux de croissance observés et simulés met en évidence la valeur prédictive du système élaboré.

Perennial Oued Zegzel and temporary Oued Cherraa are parts of the same watercourse. Coinertia analysis showed the cleardistinction between these two parts and the close relationship of the faunal assemblages with the characteristics of the water. Theheadwater course of the Zegzel is covered with dense terrestrial vegetation whose debris were consumed by abundant shreddersdominated by the prosobranch Melanopsis praemorsa. The lower course of the Zegzel has sparse riparian vegetation and muchfine detritus, and collectors such as Ecdyonurus rothschildi, Caenis luctuosa, the Diptera Corynoneurinae and Tanytarsini,occurred. In contrast, dry, flowing-, and standing-water periods succeed each other in the Cherraa and terrestrial vegetation oftengrows in its bed. M. praemorsa was replaced by the air-breathing pulmonate Physa acuta, accompanied by the adults and larvaeof flying insects. However many shredders did not develop on the abundant plant litter. The short length of the submersionperiod was probably responsible for this lack of efficiency in the exploitation of such a non-limiting food resource.

The endemic Megaleptoperla diminuta (Plecoptera : Gripopterygidae) was numerous on introduced watercress, Nasturtium microphyllum in Waikoropupu Springs, New Zealand. Adult females laid eyed ova. There appear to be about 15 nymphal instars and a non-seasonal, one year life cycle. Ovoviviparity and viviparity in Australian and New Zealand Plecoptera and Trichoptera may be associated with seasonal aquatic vegetation and fluctuating water levels.

A new species of small cyclopoids from subterranean waters of India is described in a newly established subgenus,Kiefercyclops n.sg., of the genus Haplocyclops Kiefer, 1952. Genital double-somite with ovipores situated in the posterior half,antennula without the lateral seta on the ultimate segment, and caudal rami with the lateral seta inserted in the proximal half areamong the most important characters of H. (K.) fiersi n.sp., that warrant its position in the genus Haplocyclops. Also, the newspecies differs from the other six congeners by several autapomorphic characters, most of them being reductions in armatureand/or segmentation of the appendages. In particular, the degree of reductions concerning the segmentation of the swimminglegs makes it the most reduced free-living cyclopoid, with both rami of third and fourth legs, as well as the endopod of secondleg being one-segmented in both sexes. A key to species of Haplocyclops is given at the end of this paper.

Dans cette première note, 13 taxons, dont 5 endémiques de Nouvelle-Calédonie, sont examinés au microscope électronique à balayage (M.E.B.) et au microscope électronique à transmission (M.E.T.). La liste des espèces observées est la suivante : Amphipleura guillauminii, Achnanthes lata, Brachysera neocaledonica var. angusta (nov. comb.), Cocconeis neocaledonica, Cymbella delicatula, Cymbella subturgida, Denticula elegans, Epithemia cistula, Navicula bryophila, Navicula viridula var. rostellata, Stenopterobia intermedia, Surirella neocaledonica var. punctata. La structure de Cocconeis neocaledonica Maillard se révèle très originale.

La fécondité et le développement de Moina macrocopa, seul Cladocère des bassins de lagunage de Marrakech, ont été étudiés au laboratoire à 7 concentrations en algues et à 5 températures différentes. L'effet de la densité de population et du groupement a été également testé. Les conditions de carence alimentaire sont une des principales causes de la réduction de la fécondité de M. macrocopa. Nous avons montré qu'un apport insuffisant de nourriture correspondant à une concentration en algues inférieure à 3,125.104 cellules/ml, supprimait tout phénomène de reproduction. En revanche, l'accroissement du niveau des ressources, au delà de cette concentration seuil de reproduction, était à l'origine d'une amélioration de la fécondité chez M. macrocopa qui se traduit par une augmentation du nombre de portées suivie par l'augmentation du nombre de jeunes par portées. Les expériences réalisées ont permis également de démontrer l'influence néfaste d'un accroissement de la densité de population sur la fécondité de M. macrocopa. Cependant, aucun effet de groupement sur les processus de reproduction n'a été mis en évidence chez cette espèce.

A l'aide de plusieurs séries de prélèvements réalisés dans la plaine de la Bekaa, les auteurs dressent un premier inventaire des Oligochètes aquatiques du Liban. 41 genres ou espèces appartenant à 7 familles sont ainsi recensés. Ce peuplement et celui déjà connu d'Israël sont les seules données sur la faune d'Oligochètes aquatiques du Moyen-Orient.

The programme LIFE Nature "Conservation and restoration of habitats of the Rhine fringe" (2002-2005) focussed on the assessment of the conservation status of terrestrial and aquatic habitats. Along the Rhine fringe, the degree of connection between waterbodies and the river main channel determined the water flow (surface or phreatic waters, flow velocity) and induced flood disturbances (hydromorphological quality, scouring effect). A new typology based on metrics characterizing the conservation status, was proposed for the upper Rhine floodplain. Seven physical and biological metrics were selected: specific richness, presence or absence of rare, polluto-tolerant and exotic species, species abundance, degree of connection, and trophy level defined by the macrophyte community. Aquatic macrophytes surveys were conducted at 315 sites along the Rhine French fringe. Multiple correspondence analysis and discriminant analysis were used to define metrics scores in a preliminary network of 129 macrophytes surveys stands. Metrics were combined to give a measure of the conservation status of the 315 sites. Five classes of the conservation status have been defined from degraded to excellent status. The mapping of the conservation status was realized to answer the question addressed by the program “Life Nature”. We discuss on the choice of the metrics and their justification in the definition of the conservation status. The method was tested in the fluvial hydrosystem of Ill river, the main tributary of the Rhine river in the Alsace floodplain, and compared to the French trophic index based on macrophytes, IBMR.