Contribution à la connaissance des Desmidiées du Sud-est de la Province de Québec et de la Gaspésie

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Recherches écologiques sur les faunes des plages arbitées de la région d'Arcachon

Resume 1. Le présent travail est consacré à l'étude écologique des plages abritées de la baie d'Arcachon (France). L'auteur tout d'abord, reconnaît et localise dans la région étudiée les quatres zones classiques qui partagent les estrans meubles abrités: slikke, haute slikke, schorre et zone parhalienne. Chacune d'entre elles est ensuite étudiée de manière plus détaillée, quant aux peuplements qui les occupent et aux structures édaphiques qui leur correspondent.2. Dans la slikke, l'auteur, reconnaît et décrit quatre faciès fondamentaux: les herbiers deZostera nana, les sables nus, type sables à arénicoles, les vases àNereis diversicolor et les vases à scrobiculaires. Chacun de ces faciès est analysé quant à sa teneur en eau, porosité, salinité, pH et oxygène dissous, répartition hypsométrique. En ce qui concerne la faune de ces slikkes sablo-vaseuses, l'auteur souligne l'importance de la macrofaune endogée, son caractère infralittoral, la faible mobilité de ses représentants.3. Dans la haute slikke, l'auteur reconnaît et décrit cinq faciès: les sables argileux àBledius spectabilis, les sables vaseux àCorophium volutator, les sables poreux àBledius arenarius, les aires àSpartina maritima et les microfalaises. De nouveau, sont étudiés successivement les caractéristiques abiotiques, puis les peuplements de chaque faciès; l'auteur souligne l'action réciproque des structures édaphiques sur la répartition des peuplements, mais aussi des peuplements sur les structures édaphiques. Par exempleCorophium volutator etBledius spectabilis édifient des galeries à parois stables, permanentes, qui ne peuvent être aménagées que dans certains types de sédiments; mais tandis que les galeries deB. spectabilis sont denses et étanches à la marée, celles deC. volutator sont plus dispersées et inondables; aussi la présence de l'insecte permet l'installation d'une faune d'accompagnement supralittorale, qui s'enterre au moment de la haute mer, celle de l'amphipode s'accompagne au contraire, d'une faune médiolittorale inondable.4. Enfin, dans le schorre et la zone parhalienne, l'auteur souligne l'absence de macrofaune endogée, la mobilité des peuplements vagiles épigés, leur balancement saisonnier lié au régime des marées. Il montre notamment qu'en été, le schorre abrite à la fois des espèces supralittorales marines ou halobies, et des espèces adlittorales haloxènes qui, venant de la zone parhalienne, sont attirées par la richesse trophique du Puccinellietum. En hiver, au contraire, la fréquence des immersions dans le schorre oblige la faune à refluer dans la zone parhalienne, où elle trouve son abri.5. Une classification des faciès étudiés en fonction de leur teneur en eau écologiquement utilisable par la macrofaune, un tableau de correspondance entre slikke, haute slikke, schorre et zone parhalienne d'une part, et étages intertidaux d'autre part, enfin une comparaison entre les peuplements des plages abritées et plages semi-abritées, complètent l'ensemble du travail.

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Ecological research on the faunas of the sheltered beaches of the region of Arcachon

In these ecological studies of the sheltered beaches of the bay of Arcachon (France), the author distinguishes and locates four traditional zones: slikke, upper slikke, schorre and parhalian zone. Animal communities and edaphic structures of each zone are treated in detail. In the slikke, four fundamental facies are distinguished:Zostera nana zones, bare sands (such asArenicola sands),Nereis diversicolor slime andScrobicularia slime. Each facies is analyzed with regard to its amount of water, porosity, salinity, pH and dissolved oxygen content, as well as its hypsometric distribution. With respect to the fauna of sand and slime slikkes, the importance of the endogeous macrofauna, its infralittoral characteristics and the low degree of mobility of its species are emphasized. In the upper slikke five facies are described:Bledius spectabilis clay sands,Corophium volutator slimy sands,Bledius arenarius porous sands,Spartina maritima areas and micro cliffs. Again, abiotic characteristics and animal communities of each facies are studied successively. The importance of edaphic structures for the distribution of animal communities, and vice versa, is stressed. For instance, the amphipodCorophium volutator and the coleopteranBledius spectabilis build tubes with firm and permanent inner surfaces only in certain types of sediment: yet, while theBledius spectabilis tubes are dense and watertight, those ofCorophium volutator are less tight and often flooded. Thus, the presence of the insect allows a supralittoral fauna to establish itself, whereas that of the amphipod is, in contrast, accompanied by a mediolittoral fauna resistant to flooding. In the schorre and parhalian zone, endogeous macrofauna elements are entirely absent; the vagrant epigeous species exhibit considerable degrees of mobility, migrating according to tidal rhythms. In summer, the schorre zone shelters both marine supralittoral or halobiotic species as well as adlittoral haloxene species which, coming from the parhalian zone, are attracted by the trophically rich Puccinellietum. In winter, however, frequent floodings of the schorre force the fauna to retreat to the parhalian zone for shelter. A classification is presented of the facies studied, based on the amount of water ecologically usable by their respective macrofaunas. The relationships between slikke, upper slikke, schorre and parhalian zone on the one hand, and the intertidal zones on the other are illustrated in the form of a synopsis. Finally, a comparison is made between animal communities of sheltered and of partly sheltered beaches.

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Ce travail constitue la 2ème partie d'une thèse de Doctorat ès Sciences naturelles soutenue à la Faculté des sciences de l'Université de Bordeaux (n^o d'ordre 197) et intitulée «Recherches écologiques sur les faunes des plages arbitées et des étangs saumatres de la region d'Arcachon». L'exemplaire dactylographié de la thèse in extenso a été déposé au C.N.R.S. et enregistré sous le n^o A.O. 1612.     

dÉcologie des diatomées d'eau douce de la région centrale du Portugal

Tychoplanktonic and epilithic diatom samples were taken monthly during one year at 18 sites in small lowland rivers in the northern central region of Portugal. Canonical correspondence analysis was used to explore the relationships between measured environmental variables and patterns in the diatom assemblages. Conductivity, HCO₃⁻, and chemical oxygen demand (COD) were the most significant environmental variables influencing the structure of the tychoplankton and of the epilithon. Other less important variables, such as K⁺, Fe, N(NO₃⁻), and Na⁺ also explained significant (P < 0.05) amounts of variance. The ordination diagrams showed very similar distribution of the tychoplanktonic and epilithic diatom samples. At sites with similar geomorphology as in this study, it is possible to use only one of these samples for water quality evaluation. The optima and tolerances of some diatom taxa were calculated for the most influential variables. Although the diatoms showed high tolerances to some environmental parameters, it was possible to establish groups of taxa with defined and distinctive ecological preferences. Two species groups stood out depending on the alkalinity and mineralization of the water. With a moderate conductivity (> 600 μS·cm⁻¹), alkaline pH, HCO₃⁻ concentrations equal or higher than 150 mg·l⁻¹, the first group includes Achnanthes hungarica Grunow, Amphora pediculus (Kützing) Grunow, Bacillaria paxillifera (O. F. Müller) Hendey, Cymatopleura solea (Brébisson) W. Smith, Navicula accomoda Hustedt, Navicula lanceolata (Agardh) Ehrenberg, Navicula trivialis Lange-Bertalot, Nitzschia hungarica Grunow. In waters of lower conductivity (varying between 72 and 262 μS·cm⁻¹) slightly acid pH (6 to 6.5) and HCO₃⁻¹ lower than 46 mg·l⁻¹ the following species were common: Achnanthes oblongella Östrup, Achnanthes subatomoides (Hustedt) Lange-Bertalot, et Archibald, Cymbella gracilis (Ehrenberg) Kützing, Cymbella naviculiformis Auerswald, Diatoma mesodon (Ehrenberg) Kützing, and Eunotia exigua (Brébisson) Rabenhorst. Considering COD, two further groups were distinguished. At high values (> 40 mg·l⁻¹) the following taxa were observed: Achnanthes delicatula (Kützing) Grunow, Navicula capitata Ehrenberg var. hungarica (Grunow) Ross, Nitzschia nana Grunow, Pinnularia interrupta W. Smith, Thalassiosira pseudonana Hasle & Heimdal, Thalassiosira weisflogii (Grunow) Fryxell et Hasle. For lower values than 19 mg·l⁻¹, we found Cymbella naviculiformis Auerswald, Diatoma mesodon (Ehrenberg) Kützing, Eunotia exigua (Brébisson) Rabenhorst, Fragilaria arcus (Ehrenberg) Cleve, and Nitzschia epithemioides Grumow var. disputata (Carter) Lange-Bertalot.     

Aspects toxiques du cuivre sur la biomasse et la productivité du phytoplancton de la rivière du Saguenay,Québec

In 1979 and 1980, batch culture experiments were conducted to observe the inhibitory effect of copper ion (concentrations of 10, 50, 100, 200 and 400 µg Cu · l^–1) on the standing crops and photosynthesis of phytoplankton of the Saguenay River (for 124 hours) and in Chlorella vulgaris (for 8 days). These algal assays were carried out using the surface water of the Saguenay River. In natural populatoins of phytoplankton, it was found that photosynthesis was more sensitive than growth: at the lowest concentrations, such as 10 µg Cu · 1^–1, copper seemed to increase the chlorophyll concentrations whereas the rates of primary production show a decrease of 60% with respect to the control. At higher concentrations of copper, the effect is weak in chlorophyll concentrations and more pronounced in the rates of primary production (decrease of 86 to 90%). The pennate diatoms are dominant (in all the samples) and these organisms are known as relatively resistant to copper. In Chlorella vulgaris, it was observed that with 100 µg Cu · 1^–1, chlorophyll concentrations and rates of photosynthesis respectively decrease by 63 and 99% with respect to the control. At higher concentrations of copper, a maximum decrease of 70% and 99% respectively for chlorophyll concentrations and rates of primaryproduction are observed.

     

Nouvelles données sur les macro-invertébrés du Turonien de la région de Libreville (bassin côtier nord-gabonais)

Thirteen species of macroinvertabrates have been identified for the first time from the Turonian deposits of the Libreville region. Seven ones correspond to bivalves: Lima (Plagiostoma) subsimplex Thomas and Péron, 1890, ?Osteomya sp., Plicatula ferryi Coquand, 1862, P. fourneli Coquand, 1862, P. ventilabrum var. suffetulensis Pervinquière, 1912, Plicatula sp., Pleuromya sp.; three other ones are echinoid species: Mecaster batnensis (Coquand, 1862), Mecaster nicaisei (Coquand, 1862), Mecaster sp.; and the last three are gastropods: Cylichna sp. ? Pterocerella poinsettiformis Stephenson, 1941, Columbellina sp. Excepted Plicatula ferryi Coquand and P. ventilabrum var. suffetulensis Pervinquière which are identified in the Senonian of Gabon, all species are found for the first time in Gabonese coastal basin. Their paleobiogeographic distribution is extended to Gabon. In Gabonese coastal basin, the stratigraphic and geographic ranges of the Plicatula genus are extended in Turonian and Libreville region respectively. The macrofaunal assemblage found in the Libreville region is cosmopolitan. Its shows paleogeographical affinities with Tethys and south of South Atlantic.     

Cupule isolée,groupe de cupules isolées,plage de cupules juxtaposées et chevauchantes,nuage de cupules éparses sur les roches gravées de la région du mont Bego. Représentation de l’amas stellaire des pléiades

The protohistoric rock engravings of the region of Mount Bego, located in the Alpes-Maritimes, in the municipality of Tende, include more than 40,000 figurative engravings, such as corniforms, daggers, halberds, axes, reticulates, appendage reticulate, rectangular or oval beaches, anthropomorphs, geometric figures and radiant circles that we consider as an ideogram and more than 60,000 non-figurative signs, such as isolated cupules, isolated cupules of cells, small beaches of cupules, scattered clouds of cupules, bars, which although not figurative are all highly significant. All these engravings, inscribed on more than 4150 rocks spread over 1500 hectares, in eight high mountain valleys, most often made with small cups, were not carried out at random. They have been traced in relation to economic concerns, cosmogonic myths and cultural traditions of the farming and pastoral peoples of the Copper Age and the Early Bronze Age of the Southern Alps during propitiatory rites. It was a period corresponding to the climatic optimum of Chalcolithic where during the summer, in the lower valleys, cultivated fields and pastures dried up. The economic preoccupations of the populations who then occupied the regions located on both sides of the Southern Alps were essentially turned towards the search for water to irrigate cultivated fields and pastures, as evidenced by the petroglyphs inscribed on the rocks: sinuous lines evoking creeks or irrigation canals, rectangular or oval beaches, water catch basins, isolated wells, isolated wells, wells or scattered cups of rain or reticulates, which represent cultivated fields and pastures connected to natural holes or cracks that evoke springs and streams. During propitiatory rites, the engravers addressed the god of the storm, master of the lightning and dispenser of the fertilizing rain, to the great goddess, goddess-mother or goddess-Earth, arms raised in a position of receptivity for collect rain from the sky and bring in spring, with the return of vegetation, abundance to humans.     

Le Paléolithique de la région de Hokuriku. De la côte de la mer du Japon au centre de Honshû

The stratigraphy of the Pleistocene in the region of Hokuriku where the archeological layers are thin include different lithic industries. The only sedimentological indication is the pyroclastic fall of Aïra (AT), dated of about 30 000 years BP. We determine the age of lithic industries according to the general deposit of AT. With regard to the general trend, the chronological research is based on the comparison between the vicinity. This concerned region is situated on the western coast of the main island of Japan while giving on the Sea of Japan. This zone was frequented by all people of the Japanese archipelago during the historic time. The Paleolithic lithic industries were influenced strongly by the human groups of surroundings. This region reflects the geographical conditions of western Japan, at the same time the Northeast of Honshû and the regions of the pacific coast.     

Préserver la fertilité chez les adolescents traités pour un cancer. Le point de vue du psycho-oncologue

The question of fertility is a major concern for young adults successfully treated for cancer, which is why semen preservation should be proposed to all adolescent boys prior to treatment of a cancer. This proposal is part of the oncologist’s approach to prevent sequelae. To ensure that semen cryopreservation is conducted under good conditions and is accepted by the adolescent, it is important to have a good understanding of the psychopathology and behaviour of adolescents with cancer: their preoccupation with their body, their appearance, their sexuality, their relationships to their peers and to their parents, their value and narcissism, their identity. This helps the clinician to understand and overcome the various reasons for their difficulty (and to lessen the painful feeling of failure) or their reticence to perform semen cryopreservation: paralysed by the diagnosis of cancer, sexual inhibition, lack of understanding and ignorance, pessimism concerning outcome, incapacity to project into the future, poor relationship with parents, discredit of parenthood, fear of transmitting the cancer, etc. A good understanding of these elements can avoid an excessively rapid acceptance of a superficial opposition to this procedure that the patient could subsequently regret. Closer collaboration should be developed between oncology-haematology departments and CECOS units to provide suitable information material to adolescents, to improve the understanding of the specific psychology of adolescents, and to understand the parents’ positions.     

Les échinides du Turonien de la Formation de l’Azilé du bassin côtier gabonais dans la région de Libreville Sud

Study of Turonian echinoids from Gabon store section allowed us to distinguish 10 species belonging to 2 genera: Mecaster pseudofourneli (Péron et Gauthier 1878), Mecaster toucasanus (d’Orbigny, 1854), Mecaster africanus (Coquand, 1862), Mecaster semicavatus (Peron et Gauthier 1880), Mecaster verneuili (Desor, 1847), Mecaster cf. orbignyanus (Desor, 1857), Mecaster palpebratus (Loriol, 1888), Mecaster sp.1, Mecaster sp. 2, Epiaster michelini (Agassiz) 1847. All species are found for the first time in Gabonese coastal basin. The composition and the distribution of echinoids fauna and the sedimentary characteristics indicate a proximal shallow platform deposit environment, with warm water and soft substrate. Two types of depositional environment are suggested: (1) a deep part of the proximal platform, represented by silty limestones and (2) a shallower part of the proximal platform, represented by limestones.     

Quelques remarques sur la flore et la végétation du Canada (Ontario méridional-Québec,région de Montréal

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