Les auteurs dressent une liste des Oligochètes et Aphanoneura récoltés en Tunisie. 34 genres ou espèces ont ainsi été recensés. Tous sont nouveaux pour la Tunisie et 7 espèces sont nouvelles pour l'Afrique du Nord. Le peuplement est comparable à celui de la bordure nord de la Méditerranée mais il est plus pauvre.

Le genre Setodes est signalé pour la première fois à Madagascar. Cinq espèces nouvelles sont décrites. Les affinités de ce petit groupe relativement homogène sont asiatiques et l'hypothèse d'une colonisation probable de la Grande Île depuis l'Inde est discutée. La répartition géographique et l'écologie des espèces sont analysées en fonction de l'altitude et de la distance de la source.

Environ 1 200 exemplaires d'Hydraenidae et d'Elmidae, appartenant à 30 espèces, ont été récoltés dans le Nord du Portugal, principalement dans des ruisseaux et des petites rivières coulant sur du granité, entre 30 et 935 m d'altitude. Presque tous les Hydraenidae sont des endémiques ibériques, y compris une nouvelle espèce d'Haenydra, H. lusitana nov. sp. Quelques Elmidae intéressants, tels que Limnius perrisi mediocarinatus, Oulimnius bertrandi et O. major ont également été capturés.

Le phytoplancton a été étudié sur la rivière Lot, de juillet 1972 à juillet 1973, sur 23 stations, en corrélation avec une étude physicochimique. Les caractéristiques géographiques, hydrologiques et physicochimiques sont brièvement données. Les populations algales sont étudiées par des comptages au microscope inversé. La liste des principales espèces est donnée : dans leur majorité, les espèces recensées sont fréquentes dans les milieux oligotrophes à β mésosaprobes. La dérive des algues benthiques est évaluée (pourcentage moyen du nombre total des cellules en suspension : 10 %). Diatomées et Euchlorophycées représentent plus de 90 % de la biomasse. La biomasse varie de 0,7 g/m3 en hiver à 9 g/m3 en été. Le cycle annuel du phytoplancton est à peu près semblable à celui des lacs tempérés. L'incidence des composantes physiques, chimiques et biologiques sur la croissance des algues est discutée. Nitrates, phosphates et silice ne semblent pas jouer un rôle de facteur limitant de la croissance du phytoplancton en été. Le développement estival des algues est lié aux faibles débits circulant sur la rivière canalisée.

The epithelia of the main organs likely to be involved in contaminant uptake, viz. mantle and gill were studied in the Asiaticclam Corbicula fluminea as a base for future ecotoxicological studies. On its margin, the mantle epithelium displays three foldsseparated by two grooves. The outer epithelium made of cubic cells, and the periostracal groove are involved in the formation iscomposed of the shell, secreting crystals and the periostracal lamella respectively. In the median area, the inner epithelium iscomposed of three cell types: ordinary epithelial cells, ciliated cells and mucocytes. The gill epithelium displays two structurallyand functionally different areas: a respiratory area in the interlamellar chamber and, on the opposite side, a ciliated epithelium.The respiratory epithelium is composed of thin pavement epithelial cells. The ciliated epithelium is made of different cell types:lateral ciliated epithelial cells, secretory cells, latero-frontal ciliated cells and ciliated frontal cells. The role of the secretory cellsis particularly discussed in relation to their structural similarity with lower vertebrate chloride cells (ionocytes) involved in iono- andosmoregulation processes.

This study combined several features of acoustic and electromagnetic (EM) waves-based devices including sub-bottom profiler (SBP), side-scan sonar (SSS) and ground penetrating radar (GPR), and in situ sediment data to study responses of bottom sediments after carp removal in Lake Wingra. In 2007, i.e., before carp removal, macrophytes only grew to a water depth of 2 m. Meanwhile, GPR data showed no visible sublayer in vegetated regions, while SBP data revealed a loose and fluffy sediment layer in unvegetated regions, easily affected by wave or current motions. The field data showed that suspended sediment concentrations (SSC) were much greater in unvegetated regions than those in vegetated regions during a one-day wind event, and the resuspended sediments could remain suspended in the water column for two days. In 2009, i.e., after more than half (51%) of carp were removed, the fluffy sediment layer recognized by SBP became thinner or even disappeared, and both SBP and SSS results showed that submerged macrophytes started growing in deeper water. In situ sediment data presented that bulk sediment density and critical shear stress became greater, and bottom sediments consolidated and were harder to be resuspended. Secchi depth collected between 2008 and 2010 was greater than that in the previous 10 years, indicated clearer water state. In short, the fluffy sediment layer because of carp activities may be the main source for suspended sediments to deteriorate water quality. Removal of carp is crucial for stabilizing bottom sediment and improving water clarity in this small lake.

The authors present a list of aquatic Enchytraeidae for the streams of Southern England. They examine the distribution of the species.

Description illustrée de la larve (au dernier stade) de Baetis punicus n. sp. Cette espèce, rencontrée dans le Nord-Ouest de la Tunisie, appartient au groupe alpinus : elle est comparée à cette dernière espèce et à B. maurus Kimmins.

The abundances of the different compartments of the microbial loop (i.e., viruses, heterotrophic bacteria, heterotrophic nanoflagellates, and pigmented nanoflagellates), total (TPP) and excreted (EPP) primary production, bacterial production (BP), viral lytic activity (LA), and bacterivory by nanoflagellates (FG) were measured on June 15 and 16, 1998, in a moderate-altitude oligomesotrophic lake (Lac Pavin, France), at 5 and 10 m depths. At both depths, losses of the bacterial community by viral lysis (LA5 m = 1.7 x 106 cells.1-1.h-1, LA10 m = 2.0 x 106 cells.1-1.h-1) were, on average, lower than those due to the grazing activity of flagellates (FG5 m = 10.3 x 106 cells.1-1.h-1 , FG10 m = 8.4 x 106 cells.1-1.h-1). A carbon budget exercise indicated that, for the sampling period and depths, 17.8 % of C from TPP (= 38.1 % of EPP) was used by bacteria. On the other hand, 52.7 % of BP (= 2.15 % of TPP) was grazed by nanoflagellates, while 11.0 % of BP (= 0.45 % of TPP) was lysed by viruses.

Phyllognathopus bassoti Rouch, 1972, originally described from Long Island, Papua New Guinea, and later reported from the Philippines, is found for the first time in India. This subterranean species is redescribed and its ecology and zoogeography are discussed. Also, the systematics of the family Phyllognathopodidae is discussed and a key to genera and species is given. As a result of the taxonomic analysis, three species are here synonymized: Phyllognathopus insularis Chappuis, 1940 and P. camptoides Bozic, 1965 with P. chappuisi Delachaux, 1924; and P. volcanicus Barclay, 1969 with P. viguieri (Maupas, 1892). It has been observed that odonate nymphs prey on adults and copepodids of P. bassoti, an interaction not known until now.

We describe here the limnological characteristics of the Santillana Reservoir (Spain) and study the phytoplankton distributionduring a typical growing season (July to November). The reservoir is a eutrophic stratified waterbody in central part of Spain,in which the average phytoplankton biomass in summer is higher than 20 µg chlorophyll a 1-1. Maximum phytoplankton biomassin 1999 occurred between the end of summer and the beginning of autumn (September-October). Cyanobacteria, that weregenerally prevalent in phytoplankton community, clearly dominated during the peak of phytoplankton biomass. Microcystiswesenbergii was dominant amongst the cyanobacteria and represented almost 100 % of the biomass at the time of maximumphytoplankton value. The importance of environmental variables triggering cyanobacterial bloom events is discussed. Ourresults indicate that neither temperature nor N/P ratio are related to the bloom development. However, high nutrient concentration(ammonium in particular) and stability of the watercolumn seems to coincide with the maximum abundance of Microcystis wesenbergii.

Les populations larvaires de Rhithrogena loyolaea ont été étudiées de 1971 à 1973 à 5 altitudes différentes entre la source (altitude : 2 350 m, température maximale : 4,5 °C, enneignement : 6-8 mois/an) et l'embouchure (altitude : 1 850 m, température maximale : 13 °C, enneigement : 4-5 mois/an) d'un torrent pyrénéen de haute montagne : l'Estaragne.

Le développement larvaire dure 2 ans au-dessous de 1 950 m et 3 ans au-dessus de 2 100 m.

La croissance s'effectue surtout au cours de la période déneigée. Elle est exponentielle en fonction du temps et dépend de la température moyenne du milieu ; les taux de croissance instantanés (exprimés en terme de poids) qui varient entre 0,01 et 0,04 jour-1 demeurent toutefois faibles à tous les niveaux.

La mortalité a surtout lieu en période déneigée. L'allongement du cycle biologique réduit par cinq le nombre de larves susceptibles d'achever leur développement. La survie larvaire est inférieure à 1 ‰ dans le haut du réseau hydrographique. Les populations sont relativement stables d'une année sur l'autre : leur abondance rend compte des capacités de « charge maximale » du torrent lorsque les conditions sont les plus défavorables.

La production du torrent est en moyenne de 0,6 g du poids sec/m2/an. Les rapports Production/Biomasse moyenne varient entre 2,6 et 3,1.

From an ecological viewpoint, diel vertical migration (DVM) of zooplankton is an adapted response to environmental factors. DVM coincides with changes in light intensity, but persists also under constant illumination conditions. This fact suggests the existence of an internal clock. In Daphnia longispina, it could be located in the eye. Indeed, the spatial distribution of the pigments containing in the eye ommatidia exhibits significant changes over time when Daphnia are kept under light/dark (LD) conditions. These variations coincide with displacements of the organisms. Furthermore, it is observed that the blue/dark conditions, which inhibit DVM, also stop changes in the distribution of pigments in the ommatidia. The modifications of the eye observed under LD white light represent either the internal clock or its manifestation.

Tetrazolium reduction and enzyme kinetics were examined to estimate the ETS activity of decomposing reed (Phragmites australis /Cav./ Trin. ex Steud.) rhizome to collect information on the activity of microbial decomposers. Optimal incubation time was determined at 22 °C. For complete enzyme extraction, 4-6 min. of homogenization was necessary. The main substrates of the enzymatic reaction were NADH and NADPH. The reaction was fastest when 2-(-p-iodophenyl)-3-(-p-nitrophenyl)-5-phenyl tetrazolium chloride (INT ; 0.8 mM), NADPH (0.25 mM) and NADH (1.7 mM) were applied simultaneously. The optimal incubation time should be less than 20 minutes. The pH optimum of the enzyme reaction is 8.0-8.4. ETS activity of decomposing reed rhizome can be used to estimate potentially the oxygen consumption of microorganisms involved in decomposition and, indirectly, the rate of decomposition.

In the present work, based on material from several localities in Brazil, we present a contribution to the taxonomy of the Terpides lineage, a monophyletic group of Neotropical mayflies that encompasses three genera: Terpides, Tikuna, and Fittkaulus. A new species of Terpides is described from the States of Espírito Santo and Mato Grosso, based on nymphs, male and female imagos. The male imago of the type species of Terpides, T. guyanensis, the nymph and male imago of Tikuna bilineata, and the nymph of Fittkaulus cururuensis are described for the first time.

1) Les larves d'Esolus et d'Oulimnius sont les seules larves d'Elminthidae européens à section transversale triangulaire. Les Oulimnius se distinguent des Esolus par la longueur de la soie apicale du deuxième article de l'antenne, qui dépasse celle du troisième segment, par l'insertion médiane, l'ornementation et la grande largeur des crochets de l'opercule anal, et par la présence de tubercules sur la carène dorsale.

2) Les larves âgées d'E. angustatus sont caractérisées par leur taille supérieure à 3 mm et par l'aspect crénelé du bord antérieur du pronotum, aspect dû au grand développement des tubercules.

3) Les larves âgées d'E. pygmaeus se distinguent de celles des deux autres espèces par la plus grande largeur de leur partie antérieure et par l'aplatissement des mamelons de la carène dorsale.

4) O. troglodytes se différencie d'O. tuberculatus et d'O. rivularis par la courbure forte et régulière du bord dorsal du neuvième segment abdominal et par la réduction du nombre des mamelons, présents seulement en avant de la carène sur les tergites abdominaux.

5) Chez les larves âgées d'O. tuberculatus, toute la partie postérieure des faces latérodorsales du neuvième segment est dépourvue de mamelons et paraît lisse et brillante alors qu'elle est recouverte de mamelons et paraît granitée chez O. rivularis. Chez les jeunes larves, la moitié postérieure de la carène des segments abdominaux est surélevée chez O. tuberculatus et non chez les deux autres espèces.

6) Toutes les espèces étudiées semblent avoir un cycle annuel, avec des métamorphoses au printemps, sauf peut-être chez O. rivularis où elles pourraient n'avoir lieu qu'en été.

Three new freshwater ameirid species were discovered in the Western Australian subterranean habitats and described in this paper. They all proved to belong to the genus Nitocrellopsis Galassi, De Laurentiis & Dole-Olivier, 1999, representing the first record of this genus in Australia. Nitocrellopsis operculata sp. nov. was collected in 2003 in the Pilbara region, during the Pilbara Regional Survey, led by the Western Australian Department of Environment and Conservation (DEC). It can be distinguished from all other congeners by the reduced armature of the antennal exopod, which is an autapomorphic feature. Also, no other species of Nitocrellopsis has cuticular windows on prosomal or urosomal somites, or six elements on the third exopodal segment of the second leg. Nitocrellopsis halsei sp. nov. and N. pinderi sp. nov. are sister-species, collected in 2007 in the neighbouring Yilgarn region, by the private environmental consulting company Bennelongia Pty Ltd. Numerous morphological similarities include somite ornamentation, armature patterns of the swimming legs and the fifth leg, as well as the shape and armature of the antennula, antenna and almost all mouth appendages, while the main differences between the two are observed in the body size and habitus appearance, caudal rami shape and size, presence/absence of large lateral pores on the fourth pedigerous somite, number of spinules on the anal operculum, number of setae on the madibular endopod, and shape of the exopod of the fifth leg. Although they differ from any other congener by a combination of characters, no significant autapomorphic features were observed. In order to find a more natural allocation of these three species, a cladistic analysis is performed on all current members of Nitocrellopsis and three outgroup taxa, based on 45 morphological characters. The resulting cladogram shows that the ingroup is well defined by at least four synapomorphies, but the Australian species from the two regions are only remotely related to each other, showing the importance of looking at small-scale patterns when inferring Gondwanan biogeography. Three sister-species pairs are recognized in the genus and a key to all 12 members is provided.

There is very little information on the genus Branchiobdella and the species relationships with their freshwater crayfish hosts inCroatia. Therefore, a base-line study was needed so that future changes in available habitat brought about by urban developmentand the probable introduction of non-native species can be accurately assessed. This investigation used preserved freshwatercrayfish collected from across Croatia between 1995 and 2005 as its source of the ectosymbionts. Crayfish species includedAstacus astacus, A. leptodactylus, Austropotamobius pallipes, A. torrentium, and the allochtonous North American species,Orconectes limosus. Only native European species of branchiobdellids were found: Branchiobdella astaci, B. parasita, B.pentodonta, B. hexodonta, B. italica, and B. balcanica, and this is the first report on the occurrence of these species, apart from B.italica, in Croatia. The distribution of these branchiobdellidans is compared with climatic and river drainage systems, andliterature reports of populations in other countries in the region.

I examined ephippial females and males of the Palaearctic Macrothrix hirsuticornis Norman & Brady, 1867 and M.tripectinata Weisig, 1934 (Cladocera: Anomopoda: Macrothricidae). Parthenogenetic and ephippial females, and males of a thirdspecies, M. dadayi Behning, 1941, are redescribed on material from the Ciscaucasian coast of the Black Sea (Russia). A series ofmale characters, useful for species discrimination was found. Ephippia of M. tripectinata and M. dadayi are covered with smallspinules, a unique synapomorphy of these species. Recent progress in Macrothrix systematics allows us to predict that thetaxonomy will improve as more males and ephippial females (currently known only in half the species), yet especially valuablefor systematics, are described.

L'influence des herbiers à Trapa natans a été analysée dans un étang de Dombes (Ain). Le couvert végétal flottant isole une couche d'eau superficielle de 5 cm d'épaisseur. Dans l'hypolimnion ainsi créé, les échanges vase-eau libèrent une quantité importante de fer et de phosphate en provenance du sédiment. La présence de Trapa natans augmente, au cours de l'été, la disparité fonctionnelle de l'écosystème.