Effets des marées sur la variation circadienne de la capacité photosynthétique du phytoplancton de l'estuaire du saint-laurent

The photosynthetic capacity of phytoplankton was measured at an anchor station in the Middle Estuary of the St Lawrence, over a period of 120 h. Hourly incubations were made in constant light conditions, under three different colour filters of 3, 4 and 23 W · m^?2. Differences in the oscillations of the photosynthetic capacities were observed in relation to the tidal regime. During spring tide, variations in the photosynthetic capacity are circadian, whereas a tidal pattern was also observed during the neap tide period. Differences in the patterns of photosynthetic capacity were probably due to changes in the gradients of physical factors and to the physiological state of phytoplankton relative to these gradients. The circadian rhythms appeared to be endogenous since they were apparent at non-saturating light intensities and since the photosynthetic potential (U_max) changed during the day.     

Du probleme de l'origine des Dinosauriens d'apres les donneesde l'ichnologie du Trias

With the data of the osteological paleontology and these of the ichnology, the authors attempt to restore the biotopes where lived the trackmakers, biotopes which have favoured in the Triassic the evolution and the expansion of the Archosaurs, the specialized Reptiles in the easy and rapid locomotion. They pointed out that the chirotheroid footprints cannot be attributed at all events to the Pseudosuchians and they come to the conclusion that Dinosaurs and Pseudosuchians, as separated groups, are appeared as early as the lower Triassic.     

Reflexions sur la systematique et l'evolution des metazoaires

Coming again to the implications, on the Metazoan systematics, of their first appearance modalities, the authors show the need of a truly phylogenetic classification; cladistic classifications are somewhat engaging and might be applicated tentatively to primitive Metazoan. Parallel to animal Protista, three independant series (sub-kingdoms) evolved: Spongiaria (+ Archaeata), non-surpassing morula-blastula larval stages, evolved the slowest (lower cambrian first-appearance); Cnidaria, at the gastrula-stage, emerged during Ediacarian and progressed little after Cambrian; Coelomata, because achieving the highest embryologic level, underwent the fastest evolution, nearly all their phyla being roughed out since the Ediacarian.     

Nouvelles observations sur les Miogypsinidés du Miocène inférieur et moyen de Provence et de Corse (France) et de Sardaigne septentrionale (Italie)

The detailed study of the Miocene strata of Bonifacio has revealed an atypical Miogypsinid assemblage. In addition to the three already cited genera, Miogypsinoides, Miogypsina and Miolepidocyclina from this region, Miogypsinodella is for the first time represented by two new species (Mdella corsicana nov. sp. et Mdella pillaria nov.sp.). The stratigraphical ranges of each genus in the Miogypsinidae are not verified here. However, Mdes bantamensis is still present in the Upper Burdigalian and the genus Miogypsinoides is also present in the Lower Langhian. Six species of Miogypsina coexist in the Upper Burdigalian (M. tani, M. globulina, M. intermedia, M. cf. sabahensis, M. cushmani, M. mediterranea) and two species are present in the Lower Langhian (M. antillea, M. digitata). This distribution is apparently an example of palaeoendemism resulting from the geographic isolation and the rotation of the Corso-Sardinian block and also from the palaeogeographical and palaeoecological favourable environment during that time.     

Sur les conditions de gisement de l'ichthyofaune oligocene d'Aix-en-Provence (Bouches-du-Rhone): Essai de definition d'un modele paleoecologique et paleogeographique

The study of the fossil fishes preserved in 19 successive fossiliferous beds sampled while excavating in the city ofAix-en-Provence permits the elaboration of a sedimentary model for the Oligocene gypsiferous marls. These seem to have been deposited on a coastal plain, in continental waters characterized by a fluctuating, very low, salt-content.     

Presence de Graptolites de l'Arenig moyen a la basede la Formation de Postolonnec (Massif Armoricain); Consequences stratigraphiques et paleogeographiques

The lowest part of the Postolonnec Formation (western Brittany) can be assigned to the middle Arenig Didymograptus nitidus Zone on graptolite evidence. Preliminary information on the Chitinozoa agrees with this age assignment, which defines more precisely the age of the underlying Grès armoricain Formation and also demands reconsideration of the problems associated with early Ordovician palaeogeography and sedimentology in the Massif armoricain.     

Chronostratigraphie de la fin de la derniere glaciation,a la lumiere des resultats de l'etude lithostratigraphique et palynologique du site de Maisieres-Canal (Belgique)

The upper part of the palaeoclimatic sequence of Maisières-Canal shows a succession of four mild episodes at thetransition between the Pleniglacial and the Late-Glacial. Those four mild fluctuations are respectively correlated with Langerie, Lascaux, Angles-sur-l'Anglin and Pré-Bölling oscillations.     

Donnè Structurales et Ultrastructurales Nouvelles sur la Conjugaison de Paramecium caudatum.

The morphologic phenomena of the conjugation of Paramecium caudatum are analysed by transverse sectioning of couples at the level of the junction zone. This orientation allows exact determination of the adjacent surfaces (which strongly suggests the absence of a paroral cone) and their relation to the ciliary fields. The modifications of the outer pellicle are studied with the electron microscope. It is shown that cytoplasmic communications occur at the top of the ridges which limit the periciliary depressions. The kinetosomes remain apparently intact but cilia and trichocysts disappear. An active role by the latter organelles is suggested for the union of the two conjugants.     

Palynoflores dans la coupe de l'Albien de Foz do Folcao (Portugal)

In the area of Lisbon (Portugal) near Foz do Folcao and along the sea-shore, the transgressive facies of the marly 0611 Albian may be seen sesting on the “Upper continental sandstones of Almargem”. On the basis of the variety and of the relative frequencies of reticulate pollen grains in particular, the following age assessment can be made. The topmost part of the “Upper sandstones of Almargem” as well as the lowermost transgressive facies, just underlaying the albian levels with associated faunas, are suggested to be middle Albian.     

Ressources complémentaires et mobilité dans le Magdalénien cantabrique. Nouvelles données sur les mammifères marins, les crustacés, les mollusques et les roches organogènes de la Grotte de Las Caldas (Asturies, Espagne)

Some animal and mineral resources, rarely identified in the levels of the Cantabrian Magdalenian, were exploited by the Paleolithic populations of the Nalón Valley (western Asturias) at the end of the Pleistocene. In this research, we present some of them, preserved in the Las Caldas Cave: dental remains and representations of marine mammals, marine crustaceans and molluscs, and diverse remains of amber and jet. These were selected, collected in ecosystems far away from the cave and, finally, transformed by the groups. These remains seem to complement the common resources exploited in Magdalenian paleoeconomy (e.g., ungulates, birds, fish, small carnivores, vegetables, flint, quartzite, quartz) recovered and exploited biotopes closest to the site. Our aim is thus to confirm a certain mobility of these communities towards the specific sources of raw material in search of subsistence resources potentially used in the activities of these communities (e.g., food, technology, social and symbolic expression, exchange).     

Decouvertes recentes de mammiferes et de mollusquesdans des formations d'age oligocene terminal et aquitanien du SE de la France; comparaison avec les gisements deja connus dans la meme region

The first brackish levels of the Aquitanian (s. lat.) of Cap Janet (B. du Rh.), contemporaneous with thoseof Carry-le-Rouet, have provided rodents and continental molluscs. They belong to the same level as the mammals of Coderet and so are correlated to the “série grise” of Barrême, the “calcaire de Reillanne”, the marls and limestones of Rougier, the gypsun of Aix. Older faunas found in the localities of “St-Henri” and “Les Milles” show that they belong to the same detritic flow as the “marnes de Viens”.     

Influence de l'intensité et de la longueur d'onde de la lumière sur le rendement des radicaux libres dans les semences de tomate et de carotte

Influence of light intensity and wavelength on the yield of free radicals in seeds of tomato and carrot.
Seeds of tomato ( Lycopersicum esculentum L. cv. Gribovsky-1180) and carrot ( Daucus carota L. cv. Santanet) were irradiated by continuous light of different wavelengths (white, blue, green, red, far-red and He-Ne laser) and different power density. Free radical output was measured using Electron Spin Resonance spectra (ESR). The dependence of the content of free radicals (FR) on the light power density was established. The yield of FR in the seeds irradiated with monochromatic light of the same power density was inversely proportional to the wavelength. The ESR spectra showed maximum absolute number of FR for white light. Successive irradiations gave cumulative effects on the output of free radicals in both directions: increase by the action of white light and decrease by the action of red and far-red light. The contact of irradiated seeds with steam decreased the amount of FR.     

Note preliminaire concernant la decouverte d'une faune et d'une flore du niveau de Ronzon dans l'Oligocene inferieur du Bassin d'Aquitaine

The new locality of Ruch (Gironde), from a lateral facies of the “Calcaire de Castillon” formation has yielded an important flora and fauna. From the biostratigraphic point of view the mammalian fauna allows to show that Ruch is contemporaneous of the reference locality of Ronzon (Auvergne).     

Remarques sur la stratigraphie des terrains tertiaires des bassins de Narbonne-Sigean et de Leucate (aude) a l'aide des micromammiferes

The discovery of rodents in the lacustrine and brackish deposits of the Narbonne-Leucate area classicaly dated as Oligocene, indicate that they are Oligocene and lower Miocene (Aquitanian) in the Narbonne-Sigean basin, and that the marls and limestones of the Leucate plateau and cliff are Pliocene.     

Analyse comparative de la séquence sexuelle chez les Ipopodes Oniscoidea de la série ligienne en relation avec le développement de la volvation chez les Armadillidiidae et les Armadillidae

A comparative study of the sexual sequence is carried out in four Oniscoidea of the ligiid series Porcellio laevis, Metoponorthus sexfasciatus (Porcellionidae), Armadillidium vulgare (Armadillidiidae) and Armadillo officinalis (Armadillidae). The differences between the four species chiefly appear in the precopulatory manoeuvres. The integration of coiling or uncoiling reactions in the sexual sequence of coiling forms is studied in two genera: Armadillidium and Armadillo. Results of the behavioral study provide information about the evolution of the group.