Un habitat de la fin du Mésolithique dans le Centre-Ouest de la France : L’Essart à Poitiers (Vienne)

The excavation of L’Essart (Poitiers) makes it possible for the first time in the west of France to understand a very particular habitat, along a river and very much marked by the firing activities. The substrate of the site assigns the shape of a dome surrounded to the east by the Clain River, to the west by a channel. Abundant vestiges allotted to the recent Neolithic lay in the lower half of a layer of brown silts. Immediately subjacent, a level of ten centimetres, located at the top of orange silts, contained burnt stones structures: 39 hearths (circular area posed flat approximately one meter of diameter) and 14 dismantled hearths. It is dated from the final Mesolithic by the extremely abundant lithic material discovered in the layer. Lithic industry is carried out in a preferential way on bajocians flints available on the slope (62%) and oxfordians flints (8%) known to approximately two kilometres. The principal characters of this industry are a frontal exploitation of core, a production of prismatic blades, many notches of Montbani type on the blades, asymmetrical trapezoids with concave truncations (of which Trapezoids of Payré), right-angled trapezoids with concave truncations, scalene triangles with flat retouches and arrows of Montclus. The analogies with Retzian (Vendée and Loire-Atlantique) are certainly numerous, but it is rather about a relationship in a vaster unit that remains to define. The non anecdotic presence of the arrows of Montclus involves the discussion on the question of the zones of contacts between Neolithic and Mesolithic of the second half of the VI^th millenium BC.     

Distribution in space and time of Cladocera (Crustacea) in the alluvial sediments of the river Rhône (France)

Two stations in a polluted section of the Rhône River downstream of Lyon (France) were investigated during a five month' period. The samples (101 water and sediment) were taken by the Bou-Rouch method at 20, 50 and 100 cm depth in the sediments and at three different distances from the waterline. Twenty-six Cladocera species, belonging to five families were found. Most of them are known to live in the Rhône River system, as well in the surface water as in the underflow. Their community structure and the time and space distribution are described and discussed in relationship with other macroinvertebrate taxa and with the oxygen content of the pumped water.

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Zusammenfassung Zwei Probennahmestellen in einem stark verschmutzten Flußabschnitt der Rhône unterhalb von Lyon (Frankreich) wurden über einen Zeitraum von fünf Monaten untersucht. Die Proben (10 l Wasser und Feinsedimente) wurden mit einer Bou-Rouch-Pumpe in 20, 50 and 100 cm Tiefe im Kiesschotterbett und in drei verschiedenen Entfernungen vom Rhôneufer entnommen. Sechsundzwanzig Cladoceren-Arten aus fünf Familien wurden gefunden. Ihre Faunenzusammensetzung und die räumliche und zeitliche Verteilung wurden beschrieben und im Vergleich zu anderen gefundenen Macroinvertebraten-Taxa und zum Sauerstoffgehalt des Interstitial-Wassers diskutiert.

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Résumé Deux stations dans une zone polluée du Rhône en aval de Lyon (France) ont été étudiées pendant une période de cinq mois. Les échantillons (10 l d'eau et de sédiment) ont été pris avec la méthode selon Bou et Rouch à des profondeurs de 20, 50 et 100 cm dans les sédiments et à trois distances différentes du bord de l'eau. Vingt-six espèces de Cladocères appartenant à cinq familles ont été trouvées. La plupart d'entre elles sont déjà connues dans l'hydrosystème du Rhône, aussi bien en surface que dans le sous-écoulement. Leur structure de peuplement et leur distribution spatio-temporelle sont décrites et discutées en relation avec les autres taxons de macroinvertébrés trouvés trouvés et avec la concentration en oxygène de l'eau interstitielle.

     

Transfers between a eutrophic ecosystem,the river Rhône,and an oligotrophic ecosystem,the north-western Mediterranean Sea

Transfer processes from a eutrophic ecosystem, the river Rhône, to an oligotrophic environment, the north-west Mediterranean Sea, were studied during the winter period, when inputs of dissolved and particulate matter are at their highest.During a cruise carried out in February 1987, salinity, temperature, turbidity, nutrients, pigments, suspended particulate matter and particulate carbon and nitrogen were measured in surface and subsurface waters near the Rhône outlet.For most of the parameters the results show that during this period a simple dilution process occurs in the river plume of the Rhône without adsorption, desorption, precipitation or biological uptake, contrary to recordings for some other rivers. All the nutrients discharged into the sea by the Rhône are available for utilization by marine phytoplankters.     

Ichthyogeographic regions and watershed size in the French river Rhône network

Fish community structure can be considered at several scales. The watershed is the largest geographic unit connecting freshwater systems. It describes the upstream-downstream gradient resulting from changes in flow rates. The watershed can also extend over distinct ecological regions. The number of native fish species recorded in each sub-watershed directly connected to the Rhône is strongly correlated with the area of the sub-watershed. Three major groups of sub-watersheds can be retained as ichthyogeographic regions: the Saône region, dominated by a large alluvial plain and rich in species, the Isère region representing the north and central Alpine rivers and the Durance region, strongly influenced by the Mediterranean climate. The River Rhône basin reveals a high diversity of native faunal regions which have to be considered in monitoring and managing the network.     

Organismes filamenteux de l’ambre du Santonien de Belcodène (Bouches-du-Rhône,France)

Millimetric amber grains associated with lignite debris were recently reported in the Santonian marine series from Belcodène (Bouches-du-Rhône, France). These are mainly yellow to reddish drop-shaped grains, more or less transparent. They reveal the presence of various microorganisms, belonging to prokaryotes (bacteria, actinomycetes) and eukaryotes (filamentous fungi) here described for the first time. These microorganisms form sometimes crusts around the amber grains and grew centripetally into the ancient resin before its solidification. The depositional environment of amber was open to marine influences, while the original environment of resin flow was a coastal forest with dominant angiosperms.     

Nouvelles recherches sur l’identité culturelle et stylistique de la grotte Chauvet et sur sa datation par la méthode du C

The discovery of Chauvet cave, at Vallon-Pont-d’Arc (Ardèche), in 1994, was an important event for our knowledge of palaeolithic parietal art as a whole. Its painted and engraved figures, thanks to their number (425 graphic units), and their excellent state of preservation, provide a documentary thesaurus comparable to that of the greatest sites known, and far beyond what had already been found in the group of Rhône valley caves (Ardèche and Gard). But its study – when one places it in its natural regional, cultural and thematic framework – makes it impossible to see it as an isolated entity of astonishing precocity. This needs to be reconsidered, and the affinities that our research has brought to light are clearly incompatible with the very early age which has been attributed to it. And if one extends this examination to the whole of the Franco-Cantabrian domain, the conclusion is inescapable: although Chauvet cave displays some unique characteristics (like every decorated cave), it belongs to an evolved phase of parietal art that is far removed from the motifs of its origins (known from art on blocks and on shelter walls dated by stratigraphy to the Aurignacian, in France and Cantabrian Spain). The majority of its works are therefore to be placed, quite normally, within the framework of the well-defined artistic creations of the Gravettian and Solutrean. Moreover, this phase of the Middle Upper Palaeolithic (26,000–18,000) coincides with a particularly intensive and diversified local human occupation, unknown in earlier periods and far less dense afterwards in the Magdalenian. A detailed critique of the treatment of the samples subjected to AMS radiocarbon dating makes it impossible to retain the very early age (36,000 cal BP) attributed by some authors to the painted and engraved figures of Chauvet cave.     

Gulf of fos (France): Main hydrological features (1976–1978)

Surrounded by a heavily industrialized area, subject to natural fresh water dilution (Etang de Berre, Rhône river), the Gulf of Fos is an unbalanced neritic zone. Its distrophic character is accentuated by numerous continental discharges; furthermore, the climatic instability which characterizes this region (irregular periods of winds, fluvial risings) reinforces the changing ecological conditions in the gulf waters. The present paper shows the major ecological conditions in that neritic area, and the main events occured during the 1976–1978 period, through and extensive sampling network. The principal regulating features are thus described by the mean of a mathematical data processing (Principal Components Analysis).     

Contribution a l'étude de la construction du dome chezFormica rufa (II)

Résumé L'étude plus poussée des cloisons radiaires au sommet du dôme montre que l'hétérogénéité d'amassage dans un ou deux quadrants se produit même avec un croisillon très étroit permettant la libre circulation des Fourmis sur la majeure partie du sommet.Le phénomène de l'amassage hétérogène ne se produit plus si les cloisons radiaires ne vont pas jusqu'au sommet.Si on enlève les croisillons pour les replacer peu après dans la même position, l'amassage maximum se fait soit dans les mêmes quadrants, soit dans d'autres.Des cloisons circulaires concentriques sont rapidement comblées jusqu'au bord.Des cloisons rectangulaires verticales implantées à la périphérie du dôme, tangentiellement aux contours, donnent lieu à un amassage important de brindilles en amont, jamais en aval. L'auteur propose, pour expliquer ces faits, diverses hypothèses.On a étudié aussi les parcours individuels des Fourmis transporteuses de brindilles, au cours de leur ascension du dôme. La moitié portent les brindilles près du sommet, les autres les laissent à la périphérie.

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Summary A further study of the wooden cross-pieces put on ants dome shows the heterogenity of building material gathering in one or two quadrants, even in the case of a very narrow cross piece allowing the ants to go freely around.The gathering heterogeneity is suppressed if the boards of the cross piece let the hill's top free.If the cross piece is put away, to be replaced again a few minutes later the gathering heterogeneity is seen either in the same quadrants as before, or in others.Cincular concentrical boards are quickly filled of building material till to the edge.Rectangular vertical boards put at the dome periphery, tangentially to the circonference, elicit an important gathering above the board, never below.The individual courses of the ants on the dome have been studied also: 50% place their little twigs at the top, 50% at the periphery of the dome.

     

Are the characeae able to indicate the origin of groundwater in former river channels?

The macroscopic algae Characeae are usually assumed to occur in waterbodies supplied by groundwater with low phosphate content, but the indicative value of the species is seldom defined in bibliography. Former braided channels of the Rhône river are supplied with groundwater originating from the main channel (seepage) or from hillslope aquifer. The aim of the present paper was to determine if it possible to use the Characeae as indicators of physicochemical characteristies of water in order to assess the origin of groundwater supplying former river channels. Four former braided channels of the Rhône River colonized by Characeae were investigated, and the physico-chemical characteristics of i) the channels, ii) the groundwater and iii) the river were measured over a period of several months. Species are arranged along a gradient of conductivity, alkalinity, ammonium and phosphate content of the water. Charophyte species can indicate the origin of groundwater, either seepage or hillslope nutrient-poor aquifer, and integrate both the average value of the chemical parameter, and their variations. C. hispida occurs in a nutrient-poor channel mainly supplied by highly calcareous groundwater coming from hillslope aquifer. Chara major has requirements close to those of C. hispida, but is more tolerant to periodic inputs of nutrients. C. vulgaris and N. syncarpa both tolerate mesotrophic waters originating from both hillslope aquifer and seepage, and C. globularis is associated to a channel mainly supplied by mesotrophic to eutrophic river seepage.     

Oligochaeta of the epigean and underground fauna of the alluvial plain of the French upper Rhône (biotypological trial)

Within a framework of interdisciplinary research, a biotypological trial of the epigean and underground fauna (Oligochaeta and Aphanoneura) of the alluvial plain of the French upper Rhône is proposed, according to the partition of this hydrographic complex into superficial and subterranean functional sets.Structure and dynamics of the French upper Rhône - XXXVI.With the collaboration of C. Amoros, A. Berly, M. J. Dole, M. Provot, J. L. Reygrobellet and H. Tachet.     

Spatial distribution and temporal variability of some aquatic insects in the Franco-Geneva River,Allondon

The Allodon River, a tributary of the Rhône, has suffered considerably from the recent expansion of human activities in the Geneva region. This study documents changes in its benthic fauna by comparing species richness before and after 1986 and by considering the possibilities of recolonization by drift.

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Résumé L'Allondon, affluent du Rhône, est une rivière qui a considérablemen t souffert d'une expansion récente des activités humaines dans la région genevoise. Cette étude met en lumière l'évolution de certains éléments de la faune benthique en comparant les richesses specifiques avant et après 1986, année critique pour la macrofaune benthique du bassin genevois. Elle met en évidence les possibilités de recolonisation par dérive de certains recours de l'Allondon à partir d'affluents moins perturbés.

     

Les industries lithiques de trois occupations de plein air et leur place dans le contexte Moustérien du Languedoc méditerranéen : Le Cadénas (Bédarieux, Hérault), Les Cours (Plaissan, Hérault) et Le Serre du Coucouyon (La Capelle et Masmolène, Gard)

Mediterranean Languedoc is a vast region in Southern France where Mousterian occupations, mainly concentrated in the eastern sector, are numerous. The three lithic series of the open-air sites presented in this article are yet unpublished. The techno-economical approach used to analyse these three stone assemblages has brought to light variability in Neandertal behaviour concerning raw material collection and economy in sectors more or less rich in siliceous resources, and also concerning the different production systems used and their goals. Comparisons made with other Mousterian stone assemblages in Languedoc seem to indicate ties with certain sites from the Rhône Valley.     

Galets aménagés en provenance des terrasses supérieures du Rhône au sud de Lyon (Sud-Est de la France)

Between 1990 and 1993, we found 175 pebble-tools and two flake-tools on the western high-terrace south of Lyon (Southeast, France) at two different levels (290 m and 235 m NN). Most of them show the classical spectrum of choppers and chopping-tools, joined by six protobifaces. They all belong to the developed Olduvan (Olduvan II). On the lower terrace, corresponding with its younger age, we met a more progressive pebble-tool culture. Both stocks are secondary sites, brought from the East by the most extreme tongue of the Rhône glacier and, therefore, cannot be dated exactly.     

Bactéries hétérotrophes aérobies prélevées devant le delta du rhône. I- estimation quantitative des populations et d#x00E9;termination

Résumé Les auteurs étudient une population bactérienne prélevée au débouché du Rhône en Méditerranée. Une estimation quantitative a été effectuée. Elle indique une variation importante des densités bactériennes, liée à l'apport fluviatile dans la zone de prélèvements (5.10³ à l,7.10⁶ germes/ml).L'identification de 224 souches a été entreprise par des méthodes classiques de taxinomie.Les bâtonnets asporulés Gram négatif prédominent, en particulier les germes mobiles.Les souches caractérisées se rattachent aux genres Pseudomonas-Xanthomonas (49% des souches), Achromobacter-Alcaligenes (13%), Flavobacterium (13%), Bacillus, Micrococcus, Proteus, Vibrio; quelquesunes restent indéterminées ou correspondent a des levures.L'activité protéolytique est fréquente alors que l'attaque des glucides est faible.Si l'on associe les deux caractères qui permettraient de distinguer les bactéries marines des non marines, c'est-à-dire le besoin absolu de sodium et le non développement à une température de 40° C, on constate qu'il n'y a pas une bonne concordance entre ces deux critères mais on peut néanmoins assurer que 50% des souches au minimum sont d'origine marine malgré l'influence des eaux du Rhône.

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A bacterial population has been sampled in front of the Rhône outlet in the Mediterranean Sea. Quantitative estimations of cells density show important variations resulting from river outflow; data ranged from 5 × 10³ to 1,7 × 10⁶ cells/ml.Standard taxinomic methods are used to assign tentative genera. Most of the bacteria are Gram negative sporeless rods, especially those which are motile. The strains belong to the genera Pseudomonas-Xanthomonas (49%), Achromobacter-Alcaligenes (13%), Flavobacterium (13%), Bacillus, Micrococcus, Proteus, Vibrio; a few remain unknown or are not bacteria but yeasts.Many strains hold proteolytic activity potential; on the contrary carbohydrates are scarcely assimilated.In spite of the influence of river waters, 50% of the strains are obviously from marine origin.

     

Bactéries hétérotrophes aérobies prélevées devant le delta du rhône. II — Détermination des exigences nutritionnelles. Comparaison avec des souches provenant d'autres biotopes

Résumé Les auteurs comparent un lot de 114 bactéries prélevées dans des eaux eutrophes situées devant le delta du Rhône à deux lots de souches appartenant également au bactérioplancton méditerranéen, le premier prélevé dans des eaux oligotrophes (200 souches), le deuxième constitué par des germes épiphytes-saprophytes d'algues planctoniques (57 souches).Plus de 50% des bactéries épiphytes-saprophytes ont des besoins vitaminiques; peu d'entre elles se développent sur le glucose et les acides organiques; la plupart exigent des milieux complexes. Au contraire, les souches de pleine eau présentent un grand pouvoir de synthèse qui leur permet de croître sur des substrats simples.Dans l'ensemble, le glucose n'est pas un substrat carboné universellement assimilé en présence d'azote minéral, au contraire des acides aminés, qui sont rapidement et efficacement utilisés. Cette utilisation préférentielle des acides aminés serait plus marquée pour les bactéries des eaux oligotrophes que pour celles des eaux eutrophes.

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Aerobic heterotrophic bacteria isolated in front of the Rhône outlet. II — Nutritional requirements. Comparison with strains from different origin.One hundred and fourteen bacteria have been isolated from eutrophic surface sea waters sampled in front of the Rhône outlet (Mediterranean Sea). Their vitamins requirements as a whole and growth potentials were studied with the West and Lochead's method. Results are compared with those obtained with 200 strains isolated from oligotrophic surface waters and 57 strains living epiphytically or saprophytically on diatoms sampled offshore.It appears that more than 50% of the epiphytic-saprophytic bacteria require vitamins; a few grow on glucose and organic acids, most need complex media. On the opposite, simple organic substances support the growth of free-living bacterioplankton; this capability obviously results from their high synthetizing power.Data support the opinion that the glucose should not be considered as an usual source of carbon for the bacteria studied as a whole, when a mineral nitrogen source is present. On the contrary, the amino-acids sustain fast growth. Nevertheless this preferential use is more related to the strains sampled in the oligotrophic waters than to those of eutrophic waters.

     

Baume Flandin et Abri du Maras : deux exemples de débitage laminaire du début du Pléistocène supérieur dans la Vallée du Rhône (sud-est, France)

Assemblages with blades are rare in the south of Europe and most of them are dated from the isotopic stages 4 and 3. The blades are, otherwise, often produced on Levallois cores with unipolar and bipolar methods. According to the sites, the blades are more or less retouched as different kinds of tools. However, there are no specific links between this blank and the tools, and never between the artefacts and the fauna remains (activities). The hypothesis of traditions or needs among time and space are asked without answer, while the blades are present in the north of Europe and the Near East in far older periods. Several sites can be considered to describe the variability of the technical behaviour and the archaeological context of the blades in south-east France, extending to north Italy. The two sites, Abri du Maras and Baume Flandin, located in the middle Rhône valley, yield evidence of a laminar debitage linked to a Levallois method and a “direct” method. The technical choices used in the two sites are accorded to the specificity of the laminar assemblages in the southern Europe.     

Environmental and macroinvertebrate dynamics in the Lower Rhône River and a lateral dike field: a study matching two functioning descriptors

Environmental variables and macroinvertebrate communities are studied in two sites of the Lower Rhône River, the main channel and a lateral, occasionally connected dike field. Environmental variables and faunistic communities allow discrimination the two compartments. The environmental and faunistic differences the two sites change over time. The physical and chemical differences are significantly correlated with water discharge of the main channel. The faunistic ones are significantly correlated with the temperature of the dike field water. The connections between the main channel and the dike field could be very important to maintain a high heterogeneity of the habitat, and for recolonization of the main channel after a perturbation.     

Macroinvertebrates as ‘describers’ of morphological and hydrological types of aquatic ecosystems abandoned by the Rhône River

Samples of aquatic macroinvertebrates were taken from abandoned beds of the river Rhône in the Brégnier-Cordon area. This sector of the French Upper Rhône is particularly rich in old beds or lônes which vary in age and morphological type and have more or less direct connections with the river.Samples were collected using a hand net in eight different lônes. The results concerned five groups of fauna: Mollusca, Crustacea, Ephemeroptera, Coleoptera, Trichoptera. The study revealed a wide range of fauna, and the fact that group of taxa can be used to describe types of lônes defined by morphological and hydrological characteristics. This kind of research adds to our understanding of how such aquatic ecosystems evolve, and may be applied in a more general way to other important river systems.     

Relecture d’un modèle architectural du III millénaire provençal : l’Habitation n 1 du Collet-Redon à La Couronne (Martigues, Bouches-du-Rhône)

The open-air site of Collet-Redon (Martigues, Bouches-du-Rhône) was discovered in the 1940s, and excavated by M. Escalon de Fonton until the beginning of 1980s. Those pioneering works gave up important series of artefacts and domestic structures of Late Neolithic and Bronze Age that permit to define a new Neolithic culture: the Couronnien group. The importance of this establishment, as a reference in research on Late Neolithic period in South of France, is particularly based on built remains revealed in a sector called “Habitation no. 1”. Quantity and quality of architectural structures allowed M. Escalon de Fonton to describe a Neolithic domestic unit, which became a model for interpreting other regional sites. Since 1999, various studies of artefacts and structures, coupled with an excavation, have been engaged in order to discuss first interpretations. The purpose of this article is to present our results concerning architectural remains of “Habitation no. 1” sector. Study of ancient publications and new observations on structures permit us to suggest a revision of the plan proposed for this third millenary construction.