La faune interstratifiée dans les gypses Messiniens de Los Yesos (bassin de Sorbas, SE Espagne): implications
De récentes investigations menées sur les niveaux fossilifères interstratifiés dans les gypses messiniens de Los Yesos (bassin de Sorbas, Andalousie) ont permis la récolte d'une macrofaune et d'une microfaune marines diversifiées avec au total plus de 80 espèces identifiées représentant principalement des bivalves, des échinides, des foraminifères, des ostracodes, des crustacés décapodes et des bryozoaires... L'assemblage est caractéristique d'un milieu de plate-forme de type infralittoral inférieur ~ circalittoral supérieur. Sur le plan stratigraphique, la faune présente un net cachet messinien, mais contient des espèces qui survivront du Pliocène ~ l'Actuel au sein du bassin méditerranéen. Ces résultats pèsent de nouveau le problème de l'influence réelle de la crise messinienne sur les peuplements littoraux méditerranéens.
(Geobios, n° 0016-6995, pp. 13, 07/04/2026)
MNHN, UPMC, CNRS, GR, UR, INSU - CNRS, CNRS, LDO, INSU - CNRS, UBO EPE, CNRS, GEO-OCEAN, UBS, IFREMER, INSU - CNRS, UBO EPE, CNRS, CNRS
Dissolved organic matter fluorescence spectroscopy as a tool to estimate biological activity in a coastal zone submitted to anthropogenic inputs
Here we report on an investigation of the three-dimensional excitation-emission-matrix (EEM) fluorescence spectra of unconcentrated water samples collected in 1996, 1998 and 1999 at a site particularly propitious for macro-algae development. The degradation of these macro-algae was studied to determine the influence of their exudates on natural water EEM fluorescence spectra. This work demonstrates that biological activity is one of the major factors involved in the formation of the blue-shifted fluorescence band observed in marine waters (β component Ex/Em = 310-320 nm/380-410 nm); our study also shows that fluorescence can be used to evaluate the biological activity both quantitatively and to determine its different phases. \textcopyright 2000 Elsevier Science Ltd.
(Organic Geochemistry. vol. 31, n° 0146-6380, pp. 1765--1781, 07/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Contribution to a synopsis of marine species richness in the Pertuis Charentais Sea with new insights in soft-bottom macrofauna of the Marennes-Oléron Bay
The catalogue of soft-bottom macrofauna in the Marennes-Oléron Bay (French Atlantic coast) has been updated from a benthic survey conducted in April-May 1995. 262 stations were selected using a stratified random strategy based on sediment types and bathymetric levels. 231 soft-bottom macrofauna species were identified. A synopsis of all available literature since the first local marine study published in 1710 by Antoine Ferchauld de Réaumur indicated that 60 benthic species were reported in the Marennes-Oléron Bay for the first time. The sampling effort, i.e. more than 1 station per km2 and size of the sieving square mesh (1 mm), can partially explain these results. Most of the new recorded species were crustaceans (28 species) and polychaete annelids (25 species) for only five molluscs. First report of Ocinebrellus inornatus, Mollusca Gastropoda, should be noted for the European Atlantic coasts. Additionally, alteration of subtidal habitats, colonized by Crepidula fornicata Linnaeus (Mollusca, Gastropoda) since the 1970's, may also have facilitated the recruitment and spread of some annelid polychaetes which were not previously reported in the Marennes-Oléron Bay. The total number of macrofauna species in the Pertuis Charentais Sea is 858.
(Cahiers de Biologie Marine. vol. 41, n° 0007-9723, pp. 181-222, 07/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LIENSs, INSU - CNRS, ULR, CNRS
The proliferating Gastropoda Crepidula fornicata may stimulate macrozoobenthic diversity
Since the late 19th century, the accidentally introduced Gastropoda Crepidula fornicata has been invading sheltered coastal waters of western Europe. The consequences of this proliferation on macrozoobenthic communities were studied in the Bay of Marennes-Oléron, France. Crepidula fornicata was found in a wide range of sediment grain sizes and depths, with however, a predilection for shallow muddy areas where abundance and biomass reached 4770 ind m−2 and 354 g DW m−2, respectively. Soft-sediment macrofaunal assemblages were compared in similar habitats, in the presence and absence of C. fornicata. In muddy and medium sand areas, abundance, biomass and species richness of macrofauna were generally greater in presence of C. fornicata, with Annelida dominating, although the differences were significant (P<0.05) only in one location out of five. The species composition was moderately different in the presence of C. fornicata. In coarse sand, the abundance of C. fornicata was low and did not affect abundance, biomass and species richness of the macrofauna. However, species composition differed where C. fornicata was absent, with a higher proportion of mobile Crustaceana. The effect of C. fornicata on benthic communities differs in relation to the habitat they colonize: in muddy sediments, the presence of C. fornicata apparently stimulates zoobenthic community diversity and abundance (mostly deposit-feeders), whereas in coarser sediments, macrofauna community is different (more suspension-feeders) from the community associated with C. fornicata.
(Journal of the Marine Biological Association of the United Kingdom. vol. 79, n° 0025-3154, pp. 1069-1077, 01/12/1999)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LIENSs, INSU - CNRS, ULR, CNRS
Présentation du logiciel SnB ( Shake and Bake ) Exemples d'applications
On présentera le principe de fonctionnement du programme de résolution de structures cristallographiques par méthode directe SnB (Shake and Bake) développé par une équipe de l'Université de Buffalo. Des exemples d'application aux petites protéines seront donnés, ainsi qu'à deux structures d'antibiotiques résolues au LMCP grâce à SnB. A cette occasion on passera rapidement en revue les caractéristiques de ces Pristinamycines.
(26/11/1999)
LMCP, UPMC, UPD7, IPG Paris, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Anomalous directions of the natural remanent magnetization in Late Pleistocene marine sediments from the coast of Mauritania (West Africa)
(Physics of the Earth and Planetary Interiors. vol. 115, n° 0031-9201, pp. 81-100, 01/09/1999)
LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, GEOTRAC, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Effects of metallic waterborne exposure of fisch (rainbow trout and carp) Implacations for radionuclide monitoring
(25/05/1999)
IRSN/PRP-ENV/SERIS/LECO, IRSN/PRP-ENV/SERIS, IRSN, UM2, INERIS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
A comparison between oyster (Crassostrea gigas) and sea urchin (Paracentrotus lividus) larval bioassays for toxicological studies
The respective sensitivity of oyster (Crassostrea gigas) and sea urchin (Paracentrotus lividus) embryos and larvae to salinity, and to various micropollutants (four heavy metals, three pesticides) and to two polluted sediments were compared with a simplified bioassay method. C. gigas embryos and larvae were more sensitive to copper; the sensitivity of both species to tributyltin (TBT) was practically the same; P. lividus was more sensitive to lead and mercury. The only pesticide found to be toxic was a herbicide, Dinoterbe, to which oyster larvae were more sensitive than sea urchin plutei. Of the two sediments tested, the first one had effects on P. lividus embryogenesis only; C. gigas embryos and larvae were more affected by the second sediment which was originated from a harbour and was polluted by heavy-metals. The choice of species for biomonitoring may be based on biological considerations, such as the availability of mature adults for obtaining gametes, or on the salinity of the studied area; the oyster bioassay seems to be more suitable for coastal and estuarine brackish waters, because of the broader salinity tolerance of estuarine bivalve larvae as compared to sea urchin larvae.
(Water Research. vol. 33, n° 0043-1354, pp. 1706-1718, 01/05/1999)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Effect of intermediate host size (cerastoderma edule) on infectivity of cercariae of three himasthla species (echinostomatidae, trematoda)
To understand prevalence patterns of parasites in marine host populations experimental infection studies are required. Bivalves are important host organisms to a variety of trematodes species and in our study area (Wadden Sea) three different Himasthla species co-occur in cockle populations. These species are morphologically very similar but differ with respect to various morphometric dimensions. To study the possible functional importance of differences between Himasthla cercariae (the free-living stage shed from prosobranch snails and encysting as metacercariae in bivalves), we experimentally measured the infectivity of the three congeners in regard to different size groups of juvenile cockles. The smallest species, H. interrupta, has a high infectivity in small cockles (optimum around 4 mm), whereas the two other congeners H. continua and H. elongata exhibit low infection efficiencies in cockles less than 6 mm and higher efficiencies in larger cockles. Behavioural experiments were performed to identify proximate causes underlying the observed infection patterns. Parasite avoidance behaviour of the cockle varies in a host–parasite size-dependent manner so that a large cercaria tend to provoke an avoidance response in a small cockle. The possible consequences of the observed host size preferences in relation to definitive host species (waterbirds) are discussed and it is suggested that one or more of the parasite species are adapted to other host species and that their sympatric occurrence in cockles in our study area is a result of a spinoff from their main cycle mediated through migratory birds.
(Journal of Experimental Marine Biology and Ecology. vol. 238, n° 0022-0981, pp. 259-269, 01/05/1999)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Molecular gene organisation and secondary structure of the mitochondrial large subunit ribosomal RNA from the cultivated Basidiomycota Agrocybe aegerita: a 13 kb gene possessing six unusual nucleotide extensions and eight introns.
The complete gene sequence and secondary structure of the mitochondrial LSU rRNA from the cultivated Basidiomycota Agrocybe aegerita was derived by chromosome walking. The A.aegerita LSU rRNA gene (13 526 nt) represents, to date, the longest described, due to the highest number of introns (eight) and the occurrence of six long nucleotidic extensions. Seven introns belong to group I, while the intronic sequence i5 constitutes the first typical group II intron reported in a fungal mitochondrial LSU rDNA. As with most fungal LSU rDNA introns reported to date, four introns (i5-i8) are distributed in domain V associated with the peptidyl-transferase activity. One intron (i1) is located in domain I, and three (i2-i4) in domain II. The introns i2-i8 possess homologies with other fungal, algal or protozoan introns located at the same position in LSU rDNAs. One of them (i6) is located at the same insertion site as most Ascomycota or algae LSU introns, suggesting a possible inheritance from a common ancestor. On the contrary, intron i1 is located at a so-far unreported insertion site. Among the six unusual nucleotide extensions, five are located in domain I and one in domain V. This is the first report of a mitochondrial LSU rRNA gene sequence and secondary structure for the whole Basidiomycota division.
(Nucleic Acids Research. vol. 27, n° 0305-1048, pp. 1754-1761, 01/04/1999)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS