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Sample records for bivalve corbicula fluminea

  1. Internal distribution of uranium and associated genotoxic damages in the chronically exposed bivalve Corbicula fluminea

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    Simon, Olivier, E-mail: olivier.simon@irsn.fr [Laboratoire de Radioecologie et Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat, 186 BP3, 13115 Saint Paul-Lez-Durance Cedex (France); Floriani, Magali; Cavalie, Isabelle; Camilleri, Virginie; Adam, Christelle; Gilbin, Rodolphe; Garnier-Laplace, Jacqueline [Laboratoire de Radioecologie et Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat, 186 BP3, 13115 Saint Paul-Lez-Durance Cedex (France)

    2011-08-15

    Uranium (U) internal distribution and involved effects in the bivalve Corbicula fluminea have been studied after direct chronic exposure (90 d, 10 {mu}g.L-1). U distribution was assessed at the subcellular level (Metal Rich Granules -MRG-, pellets and cytosol fractions) in two main organs of the bivalve (gills and visceral mass). Micro-localisation was investigated by TEM-EDX analysis in the gills epithelium. DNA damage in gill and hemolymph samples was measured by the Comet assay. The 90-d exposure period led to a significant increase of U concentration in gills over time (x5) and a large U quantity in subcellular granules in gills. Finally, a significant increase (x2) in DNA damage was noted in exposed gills and haemocytes. This study shows that the accumulation levels and consequently the potential toxicity cannot be successfully predicted only on the basis of concentration in water or in tissues and subcellular fractions after chronic exposure. - Highlights: > Relevant information concerning the chronic impact of uranium on biota is scarce. > We study its biological speciation to explain bioavailability, accumulation, toxicity. > 80% of U accumulated was measured in the pellet fraction (organelles + granules/MRG). > Chronic exposure to U induced genetic damage in gill and haemolymph cells of the bivalve.

  2. Proteomic Profiling of Cytosolic Glutathione Transferases from Three Bivalve Species: Corbicula fluminea, Mytilus galloprovincialis and Anodonta cygnea

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    José Carlos Martins

    2014-01-01

    Full Text Available Suspension-feeding bivalves are considered efficient toxin vectors with a relative insensitivity to toxicants compared to other aquatic organisms. This fact highlights the potential role of detoxification enzymes, such as glutathione transferases (GSTs, in this bivalve resistance. Nevertheless, the GST system has not been extensively described in these organisms. In the present study, cytosolic GSTs isoforms (cGST were surveyed in three bivalves with different habitats and life strategies: Corbicula fluminea, Anodonta cygnea and Mytilus galloprovincialis. GSTs were purified by glutathione-agarose affinity chromatography, and the collection of expressed cGST classes of each bivalve were identified using a proteomic approach. All the purified extracts were also characterized kinetically. Results reveal variations in cGST subunits collection (diversity and properties between the three tested bivalves. Using proteomics, four pi-class and two sigma-class GST subunits were identified in M. galloprovincialis. C. fluminea also yielded four pi-class and one sigma-class GST subunits. For A. cygnea, two mu-class and one pi-class GST subunits were identified, these being the first record of GSTs from these freshwater mussels. The affinity purified extracts also show differences regarding enzymatic behavior among species. The variations found in cGST collection and kinetics might justify diverse selective advantages for each bivalve organism.

  3. Proteomic profiling of cytosolic glutathione transferases from three bivalve species: Corbicula fluminea, Mytilus galloprovincialis and Anodonta cygnea.

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    Martins, José Carlos; Campos, Alexandre; Osório, Hugo; da Fonseca, Rute; Vasconcelos, Vítor

    2014-01-27

    Suspension-feeding bivalves are considered efficient toxin vectors with a relative insensitivity to toxicants compared to other aquatic organisms. This fact highlights the potential role of detoxification enzymes, such as glutathione transferases (GSTs), in this bivalve resistance. Nevertheless, the GST system has not been extensively described in these organisms. In the present study, cytosolic GSTs isoforms (cGST) were surveyed in three bivalves with different habitats and life strategies: Corbicula fluminea, Anodonta cygnea and Mytilus galloprovincialis. GSTs were purified by glutathione-agarose affinity chromatography, and the collection of expressed cGST classes of each bivalve were identified using a proteomic approach. All the purified extracts were also characterized kinetically. Results reveal variations in cGST subunits collection (diversity and properties) between the three tested bivalves. Using proteomics, four pi-class and two sigma-class GST subunits were identified in M. galloprovincialis. C. fluminea also yielded four pi-class and one sigma-class GST subunits. For A. cygnea, two mu-class and one pi-class GST subunits were identified, these being the first record of GSTs from these freshwater mussels. The affinity purified extracts also show differences regarding enzymatic behavior among species. The variations found in cGST collection and kinetics might justify diverse selective advantages for each bivalve organism.

  4. Allochthonous Organic Matter Subsidize the High Secondary Production of the Invasive Bivalve Corbicula fluminea in Minho Estuary (N-Portugal)

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    The Asian clam Corbicula fluminea is one of the most invasive species in freshwater ecosystems. In Minho estuary, this species colonize all the middle and upper part of the estuary, dominating the abundance, biomass and secondary production in River Minho tidal freshwater area (T...

  5. Micro-structure and chemical composition of vateritic deformities occurring in the bivalve Corbicula fluminea (Müller, 1774).

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    Frenzel, Max; Harper, Elizabeth M

    2011-05-01

    Vateritic deformities occurring in the invasive heterodont bivalve Corbicula fluminea from several locations in the UK were characterised in detail for the first time using scanning electron microscopy, X-ray diffraction and different geochemical techniques (electron microprobe, ICP-AES, and mass spectrometry). Large volumes of vaterite are produced abnormally in the animals' shells in the form of yellow-green bulges. These are distinguished from the aragonitic parts of the shell by their characteristic micro-structures, content of organic material, trace elemental composition and carbon stable isotope signatures. The most commonly observed micro-structures include columnar vaterite, lamellar vaterite and different irregular structures occurring in all parts of the shell. There are indications that organic material is present largely as intracrystalline impurities or nano-scale phases and not as envelopes around microstructural units. These micro-structures are novel, nothing equivalent having yet been described for other vateritic systems. Euhedral vaterite crystals also occur occasionally. The vaterite has generally higher Mg/Ca and lower Na/Ca, K/Ca than the aragonite. In addition, δ¹³C is also always lower. Microstructural characteristics would suggest loss of biological control probably due to physiological stress(es) inducing the switch to vaterite production. The vaterite might be stabilised by its higher content of organic material and magnesium.

  6. How the fluctuations of water levels affect populations of invasive bivalve Corbicula fluminea (Müller, 1774) in a Neotropical reservoir?

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    Paschoal, L R P; Andrade, D P; Darrigran, G

    2015-01-01

    Corbicula fluminea is an invasive bivalve responsible for several environmental and financial problems around the globe. Despite the invasive potential of this species, it suffers certain restrictions in lentic environments due to natural phenomena that significantly affect its population structure (e.g. water column fluctuation and sunlight exposure). The present study addresses how temporal decline of the water level in a Neotropical reservoir and exposure to sunlight affect the population structure of C. fluminea. Samplings were carried out twice in the reservoir of Furnas Hydroelectric Power Station (HPS) (Minas Gerais, Brazil), in 2011 and 2012. Population density, spatial distribution and mean shell length of C. fluminea were estimated for each year after sampling in 51 quadrats (0.0625m2) placed on three transects at different distances along the reservoir margins (0, 10 and 20 m from a fixed-point). We observed a predominance of C. fluminea in both years, with a simultaneous gradual decrease in density and richness of native species in the sampling area. Significant differences in density of C. fluminea were registered at different distances from the margin, and are related to the temporal variability of physical conditions of the sediment and water in these environments. We also registered a trend toward an increase in the density and aggregation of C. fluminea as we moved away from the margin, due to the greater stability of these areas (>10 m). The mean shell length of C. fluminea showed significant difference between the distinct distances from the margin and during the years, as well as the interaction of these factors (Distances vs.Years). These results were associated with the reproductive and invasive capacity of this species. This study reveals that these temporal events (especially water column fluctuation) may cause alterations in density, spatial distribution and mean shell length of C. fluminea and the composition of the native malacofauna in

  7. How the fluctuations of water levels affect populations of invasive bivalve Corbicula fluminea (Müller, 1774 in a Neotropical reservoir?

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    LRP. Paschoal

    Full Text Available Corbicula fluminea is an invasive bivalve responsible for several environmental and financial problems around the globe. Despite the invasive potential of this species, it suffers certain restrictions in lentic environments due to natural phenomena that significantly affect its population structure (e.g. water column fluctuation and sunlight exposure. The present study addresses how temporal decline of the water level in a Neotropical reservoir and exposure to sunlight affect the population structure of C. fluminea. Samplings were carried out twice in the reservoir of Furnas Hydroelectric Power Station (HPS (Minas Gerais, Brazil, in 2011 and 2012. Population density, spatial distribution and mean shell length of C. fluminea were estimated for each year after sampling in 51 quadrats (0.0625m2 placed on three transects at different distances along the reservoir margins (0, 10 and 20 m from a fixed-point. We observed a predominance of C. fluminea in both years, with a simultaneous gradual decrease in density and richness of native species in the sampling area. Significant differences in density of C. fluminea were registered at different distances from the margin, and are related to the temporal variability of physical conditions of the sediment and water in these environments. We also registered a trend toward an increase in the density and aggregation of C. fluminea as we moved away from the margin, due to the greater stability of these areas (>10 m. The mean shell length of C. fluminea showed significant difference between the distinct distances from the margin and during the years, as well as the interaction of these factors (Distances vs.Years. These results were associated with the reproductive and invasive capacity of this species. This study reveals that these temporal events (especially water column fluctuation may cause alterations in density, spatial distribution and mean shell length of C. fluminea and the composition of the native

  8. Bioaccumulation of selenium and induced biological effects in the filter feeding bivalve Corbicula fluminea: influence of ventilatory activity, selenium speciation and route of transfer; Bioaccumulation du selenium et effets biologiques induits chez le bivalve filtreur Corbicula fluminea: prise en compte de l'activite ventilatoire, de la speciation du selenium et de la voie de contamination

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    Fournier, E

    2005-10-15

    Selenium is an essential micro-nutrient for most of living organisms. However, toxic effects in several ecosystems have been reported in the literature. Toxicity comprehension is difficult due to the complexity of Se oxidation states in the environment. The aim of this thesis work was to acquire knowledge on the physiological and environmental factors involved in bioaccumulation and toxicity processes in the freshwater filter-feeding bivalve C. fluminea. The aims were: i) to define what the factors involved in Se bioaccumulation processes in the bivalve are, ii) to characterize Se bioaccumulation at different biological organisation levels, iii) to investigate Se toxic effects. First experiments, carried out for short term exposure duration (3 days), have permitted to underline the importance of Se chemical speciation in bioaccumulation processes in C. fluminea. It has been shown that the organic form, seleno-methionine, was much more bio-available than the inorganic forms, selenite and selenate. Moreover, the route of transfer was determinant in those processes. Inorganic forms have been better extracted by trophic route, whereas seleno-methionine has been better extracted by the direct route. In our experimental conditions, ventilation of the bivalve has not been a limiting factor for Se bioaccumulation by the direct route, whereas it has been for bioaccumulation by the trophic route. Ventilation has been largely modified by the presence of dissolved selenite and seleno-methionine. We have shown that the kinetics of seleno-methionine bioaccumulation are much more fast than those of selenite. Moreover, when introduced as SeMet, internalized Se appeared to be relatively remanent in soft tissues of C. fluminea in comparison with Se internalized when introduced as selenite. Subcellular and molecular distributions of these forms were very different. Finally, it has been shown that seleno-methionine and selenite could generate weak alterations of the anti

  9. Occurrence of the invasive species Corbicula fluminea (Bivalvia, Corbiculidae) in the Sapucaí River (São Paulo, Brazil)

    OpenAIRE

    Vianna, Marina Peixoto; Avelar, Wagner Eustáquio Paiva

    2010-01-01

    Biological invasions are gaining increasing importance due to the ecological damage and economic impacts caused by the invaders. Corbicula fluminea (Müller, 1774) is an invasive exotic bivalve introduced into Brazil in the 1970's, and it has colonized the major rivers of the south and southeast. This species, owing to its adaptations to the environment, speed of colonization and reproductive success among others parameters, quickly occupies the substrates preferred by the natives. The pr...

  10. Comparison of selenium bioaccumulation in the clams Corbicula fluminea and Potamocorbula amurensis: A bioenergetic modeling approach

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    Lee, B.-G.; Lee, J.-S.; Luoma, S.N.

    2006-01-01

    Selenium uptake from food (assimilation efficiency) and dissolved phase (influx rate) as well as loss kinetics (efflux rate) were compared between two bivalves, Corbicula fluminea and Potamocorbula amurensis. The effects of salinity and temperature on these kinetic parameters for both clam species also were evaluated. The Asiatic clam, C. fluminea, more efficiently assimilated Se associated with algae (66-87%) than Se associated with oxic sediments (20-37%). However, no consistent difference was found between Se assimilation efficiencies from both food types (19-60%) for P. amurensis. The temperature and salinity had a minor influence on the Se assimilation from ingested food. However, the effects of temperature and salinity were more evident in the uptake from dissolved sources. The influx rate of Se(IV) increased by threefold with the increase of temperature from 5 to 21??C for C. fluminea. The increase of salinity from 4 to 20 psu decreased the uptake rate constant (ku) of Se in P. amurensis from 0.011 to 0.005 L/g/h, whereas salinity change (0-8 psu) had a negligible effect on the Se influx rate of C. fluminea. The Se influx rate of P. amurensis decreased by half with the 3.5-fold increase in tissue dry weight. The rate constant of loss was greater for P. amurensis (0.029/d at 8 psu) than for C. fluminea (0.014/d at 0 psu and 0.01/d at 8 psu). A bioenergetic model suggests that dietary uptake is the dominant pathway for Se bioaccumulation in the two clams in San Francisco Bay and that interspecies differences in Se bioaccumulation can be explained by differences in food ingestion rates. ?? 2006 SETAC.

  11. Sequencing and de novo assembly of the Asian clam (Corbicula fluminea transcriptome using the Illumina GAIIx method.

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    Huihui Chen

    Full Text Available BACKGROUND: The Asian clam (Corbicula fluminea is currently one of the most economically important aquatic species in China and has been used as a test organism in many environmental studies. However, the lack of genomic resources, such as sequenced genome, expressed sequence tags (ESTs and transcriptome sequences has hindered the research on C. fluminea. Recent advances in large-scale RNA-Seq enable generation of genomic resources in a short time, and provide large expression datasets for functional genomic analysis. METHODOLOGY/PRINCIPAL FINDINGS: We used a next-generation high-throughput DNA sequencing technique with an Illumina GAIIx method to analyze the transcriptome from the whole bodies of C. fluminea. More than 62,250,336 high-quality reads were generated based on the raw data, and 134,684 unigenes with a mean length of 791 bp were assembled using the Velvet and Oases software. All of the assembly unigenes were annotated by running BLASTx and BLASTn similarity searches on the Nt, Nr, Swiss-Prot, COG and KEGG databases. In addition, the Clusters of Orthologous Groups (COGs, Gene Ontology (GO terms and Kyoto Encyclopedia of Gene and Genome (KEGG annotations were also assigned to each unigene transcript. To provide a preliminary verification of the assembly and annotation results, and search for potential environmental pollution biomarkers, 15 functional genes (five antioxidase genes, two cytochrome P450 genes, three GABA receptor-related genes and five heat shock protein genes were cloned and identified. Expressions of the 15 selected genes following fluoxetine exposure confirmed that the genes are indeed linked to environmental stress. CONCLUSIONS/SIGNIFICANCE: The C. fluminea transcriptome advances the underlying molecular understanding of this freshwater clam, provides a basis for further exploration of C. fluminea as an environmental test organism and promotes further studies on other bivalve organisms.

  12. Purification and Characterization of Hemagglutinating Proteins from Poker-Chip Venus (Meretrix lusoria and Corbicula Clam (Corbicula fluminea

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    Chin-Fu Cheng

    2012-01-01

    Full Text Available Hemagglutinating proteins (HAPs were purified from Poker-chip Venus (Meretrix lusoria and Corbicula clam (Corbicula fluminea using gel-filtration chromatography on a Sephacryl S-300 column. The molecular weights of the HAPs obtained from Poker-chip Venus and Corbicula clam were 358 kDa and 380 kDa, respectively. Purified HAP from Poker-chip Venus yielded two subunits with molecular weights of 26 kDa and 29 kDa. However, only one HAP subunit was purified from Corbicula clam, and its molecular weight was 32 kDa. The two Poker-chip Venus HAPs possessed hemagglutinating ability (HAA for erythrocytes of some vertebrate animal species, especially tilapia. Moreover, HAA of the HAP purified from Poker-chip Venus was higher than that of the HAP of Corbicula clam. Furthermore, Poker-chip Venus HAPs possessed better HAA at a pH higher than 7.0. When the temperature was at 4°C–10°C or the salinity was less than 0.5‰, the two Poker-chip Venus HAPs possessed better HAA compared with that of Corbicula clam.

  13. Low Genetic Diversity and High Invasion Success of Corbicula fluminea (Bivalvia, Corbiculidae (Muller, 1774 in Portugal.

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    Cidália Gomes

    Full Text Available The Asian clam, Corbicula fluminea, is an invasive alien species (IAS originally from Asia that has spread worldwide causing major ecological and economic impacts in aquatic ecosystems. Here, we evaluated C. fluminea genetic (using COI mtDNA, CYTb mtDNA and 18S rDNA gene markers, morphometric and sperm morphology variation in Portuguese freshwater ecosystems. The COI marker revealed a single haplotype, which belongs to the Asian FW5 invasive lineage, suggesting a common origin for all the 13 Portuguese C. fluminea populations analysed. Morphometric analyses showed differences between the populations colonizing the North (with the exception of the Lima River and the Centre/South ecosystems. The sperm morphology examination revealed the presence of biflagellate sperm, a distinctive character of the invasive androgenetic lineages. The low genetic variability of the Portuguese C. fluminea populations and the pattern of sperm morphology have been illuminating for understanding the demographic history of this invasive species. We hypothesize that these populations were derived from a unique introductory event of a Corbicula fluminea FW5 invasive androgenic lineage in the Tejo River, which subsequently dispersed to other Portuguese freshwater ecosystems. The C. fluminea asexual reproductive mode may have assisted these populations to become highly invasive despite the low genetic diversity.

  14. Detection and analysis of the microdistribution of uranium in the gills of freshwater Corbicula fluminea by SIMS technique

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    Tessier, C. [IRSN, Direction de la RadioProtection de l' Homme, Service de Dosimetrie Interne, Laboratoire de RadioChimie, IRSN, BP 17, F-92262 Fontenay aux Roses Cedex (France)], E-mail: christine.tessier@irsn.fr; Suhard, D. [IRSN, Direction de la RadioProtection de l' Homme, Service de Dosimetrie Interne, Laboratoire de RadioChimie, IRSN, BP 17, F-92262 Fontenay aux Roses Cedex (France); Simon, O.; Floriani, M. [IRSN, Direction de l' Environnement et de l' Intervention, Service d' Etude du Comportement des Radionucleides dans les ecosystemes, Laboratoire de Radioecologie et d' ecotoxicologie, IRSN, BP F6 Cadarache (France); Rebiere, F.; Jourdain, J.-R. [IRSN, Direction de la RadioProtection de l' Homme, Service de Dosimetrie Interne, Laboratoire de RadioChimie, IRSN, BP 17, F-92262 Fontenay aux Roses Cedex (France)

    2009-06-01

    The microdistribution of uranium in the gills of freshwater bivalve Corbicula fluminea following chronic direct exposure to this radioelement has been investigated using the SIMS technique. Different exposure levels and exposure durations have been studied. The SIMS mass spectra and {sup 238}U{sup +} ion images produced with a SIMS CAMECA 4F-E7 show an U accumulation with the lower aqueous U concentration (20 {mu}g/L) and the influence of the exposure levels on the bioaccumulation capacities. Furthermore, the ionic images display a heterogeneous distribution of uranium within the gill structure whatever the exposure conditions are. This study, in keeping with the ENVIRHOM French research program, was led to the conclusion that ion microscopy is an appropriate analytical method for trace elements and can give elemental cartography in a biological tissue section.

  15. Occurrence of the invasive species Corbicula fluminea (Bivalvia, Corbiculidae in the Sapucaí River (São Paulo, Brazil

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    Marina Peixoto Vianna

    2010-09-01

    Full Text Available Biological invasions are gaining increasing importance due to the ecological damage and economic impacts caused by the invaders. Corbicula fluminea (Müller, 1774 is an invasive exotic bivalve introduced into Brazil in the 1970’s, and it has colonized the major rivers of the south and southeast. This species, owing to its adaptations to the environment, speed of colonization and reproductive success among others parameters, quickly occupies the substrates preferred by the natives. The present study registers its occurrence in Sapucaí River, São Paulo State. Samples were taken at two different sites of the river with different substrates, one sandy and another muddy. Granulometric analysis and determination of the organic matter content of the sediment were then conducted. The individuals captured in sandy sediment showed higher densities, higher average size, and therefore higher average biomass.

  16. Ocorrência do molusco asiático Corbicula fluminea (Müller, 1774 (Bivalvia, Corbiculidae no baixo rio Negro, Amazônia central Occurrence of the Asian mollusc Corbicula fluminea (Müller, 1774 (Bivalvia, Corbiculidae in the lower Rio Negro, Central Amazon Region, Brazil

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    Daniel Mansur Pimpão

    2008-01-01

    Full Text Available O rio Negro é um dos maiores afluentes do rio Amazonas, mas poucos moluscos foram registrados até o momento para aquele rio, representados apenas por gastrópodes. Foi registrada a presença do molusco bivalve exótico Corbicula fluminea na margem esquerda do baixo rio Negro, no lago do Tupé e no Catalão - margem direita do rio Negro, todas localidades no município de Manaus, Brasil. O registro foi realizado por meio da coleta de conchas e espécimes vivos. É o primeiro registro de C. fluminea para o estado do Amazonas e Amazônia central.The Rio Negro is one of the biggest Rio Amazonas tributaries. Few molluscs have been registered to that river yet, represented only by gastropods. It is reported the occurrence of the exotic bivalve mollusc Corbicula fluminea in left bank margin of Rio Negro, Lago do Tupé and Catalão - right bank margin of Rio Negro, all localities in the municipality of Manaus, Brazil. The species is recorded by a collection of shells and specimens alive. This is the first occurrence of C. fluminea in the Amazon State and Central Amazon.

  17. Corbiculae fluminea as a bioindicator on the Lower Colorado River

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    US Fish and Wildlife Service, Department of the Interior — Tissue samples from Asiatic clam (Corbimla fluminea) from the lower Colorado River were analyzed for trace element concentrations. Selenium and arsenic were elevated...

  18. Invasive zebra mussels (Driessena polymorpha) and Asian clams (Corbicula fluminea) survive gut passage of migratory fish species: implications for dispersal

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    Gatlin, Michael R.; Shoup, Daniel E.; Long, James M.

    2013-01-01

    The introduction and spread of invasive species is of great concern to natural resource managers in the United States. To effectively control the spread of these species, managers must be aware of the multitude of dispersal methods used by the organisms. We investigated the potential for survival through the gut of a migrating fish (blue catfish, Ictalurus furcatus) as a dispersal mechanism for two invasive bivalves: zebra mussel (Driessena polymorpha) and Asian clam (Corbicula fluminea). Blue catfish (N = 62) were sampled over several months from Sooner Lake, Oklahoma, transported to a laboratory and held in individual tanks for 48 h. All fecal material was collected and inspected for live mussels. Survival was significantly related to water temperature in the lake at the time of collection, with no mussels surviving above 21.1 C°, whereas 12 % of zebra mussels (N = 939) and 39 % of Asian clams (N = 408) consumed in cooler water survived gut passage. This research demonstrates the potential for blue catfish to serve as a dispersal vector for invasive bivalves at low water temperatures.

  19. Veligers of the invasive Asian clam Corbicula fluminea in the Columbia River Basin: Broadscale distribution, abundance, and ecological associations

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    Hassett, Whitney; Bollens, Stephen M.; Counihan, Timothy D.; Rollwagen-Bollens, Gretchen; Zimmerman, Julie; Emerson, Joshua E.

    2017-01-01

    The invasive Asian clam Corbicula fluminea was introduced to North America in the 1930s and now inhabits most regions of the conterminous United States; however, the distribution and ecology of C. fluminea in the Columbia River Basin is poorly understood. During 2013 and 2014, 5 Columbia-Snake River reservoirs were sampled monthly from May through September, along with 23 additional lakes and reservoirs sampled once each summer. Associations among C. fluminea veligers, other components of the plankton, and environmental variables were analyzed using non-metric multidimensional scaling and canonical correspondence analysis. Corbicula fluminea veligers were found in high abundances in all mainstem Columbia-Snake River reservoirs, with an annual mean abundance of 71.2 individuals per cubic meter (inds./m3). Only 3 of 23 lakes and (non-mainstem) reservoirs contained C. fluminea, with abundances considerably lower (maximum = 21.2 inds./m3) than in the mainstem reservoirs. A diatom-dominated community preceded the spawning of C. fluminea in early summer at all sites. Corbicula fluminea veligers characterized the plankton community in late summer and were associated with cyanobacteria and high water temperatures. A third community, characterized by cyanobacteria, was apparent in non-mainstem sites in July and August. Our analyses describe the relationship of C. fluminea to the plankton community and environment, which contributes to our understanding of the possible effects of C. fluminea infestations and which waterbodies in the Columbia River Basin are at risk for infestation. Understanding the effects and environmental determinants of invasive mollusks will be increasingly important in the future with the possible arrival of zebra (Dreissena polymorpha) or quagga (D. bugensis) mussels to the region.

  20. Expression of cyp1a protein in the freshwater clam Corbicula fluminea (Müller

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    Vranković Jelena

    2011-01-01

    Full Text Available We investigated the expression of CYP1A in the foot, gill and visceral mass of the freshwater clam Corbicula fluminea in relation to polychlorinated biphenyls (PCBs exposure. Different PCBs congeners were found in the foot and visceral mass, while the expression of CYP1A was observed only in the visceral mass. However the level of CYP1A expression in the visceral mass was not related to the level of PCBs present in the tissue. Our results indicate a higher rate of biotransformation and lower threshold of CYP1A induction in the visceral mass compared with other tissues.

  1. Low Genetic Diversity and High Invasion Success of Corbicula fluminea (Bivalvia, Corbiculidae) (Müller, 1774) in Portugal

    Science.gov (United States)

    Gomes, Cidália; Sousa, Ronaldo; Mendes, Tito; Borges, Rui; Vilares, Pedro; Vasconcelos, Vitor; Guilhermino, Lúcia; Antunes, Agostinho

    2016-01-01

    The Asian clam, Corbicula fluminea, is an invasive alien species (IAS) originally from Asia that has spread worldwide causing major ecological and economic impacts in aquatic ecosystems. Here, we evaluated C. fluminea genetic (using COI mtDNA, CYTb mtDNA and 18S rDNA gene markers), morphometric and sperm morphology variation in Portuguese freshwater ecosystems. The COI marker revealed a single haplotype, which belongs to the Asian FW5 invasive lineage, suggesting a common origin for all the 13 Portuguese C. fluminea populations analysed. Morphometric analyses showed differences between the populations colonizing the North (with the exception of the Lima River) and the Centre/South ecosystems. The sperm morphology examination revealed the presence of biflagellate sperm, a distinctive character of the invasive androgenetic lineages. The low genetic variability of the Portuguese C. fluminea populations and the pattern of sperm morphology have been illuminating for understanding the demographic history of this invasive species. We hypothesize that these populations were derived from a unique introductory event of a Corbicula fluminea FW5 invasive androgenic lineage in the Tejo River, which subsequently dispersed to other Portuguese freshwater ecosystems. The C. fluminea asexual reproductive mode may have assisted these populations to become highly invasive despite the low genetic diversity. PMID:27391333

  2. Identification of larvae: The zebra mussel (Dreissena polymorpha), quagga mussel (Dreissena rosteriformis bugensis), and Asian clam (Corbicula fluminea)

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    Nichols, S. Jerrine; Black, M.G.

    1994-01-01

    There are presently four freshwater bivalves in the United States that produce larvae or veligers commonly found in the water column: two forms of Asian clams and two species of dreissenids. Portions of the geographic range of three of these bivalves, one species of Asian clam (Corbicula fluminea), zebra mussels (Dreissena polymorpha), and quagga mussels (Dreissena rosteriformis bugensis), overlap, causing problems with larval identification. To determine which characteristics can be used to separate larval forms, adult Asian clams, quaggas, and zebra mussels were brought into the laboratory and induced to spawn, and the resulting larvae were reared. Hybrids between quaggas and zebra mussels were also produced, but not reared to maturity. Characteristics allowing for the most rapid and accurate separation of larvae were hinge length, shell length/height, shell shape, shell size, and the presence or absence of a foot and velum. These characteristics were observed in laboratory-reared larvae of known parentage and field-caught larvae of unknown parentage. In most cases, larvae of the Asian clam can be readily separated from those produced by either type of dreissenid on the basis of shell size and presence of a foot. Separating the gametes and embryos of the two types of dreissenids is not possible, but after shell formation, most of the larval stages can be distinguished. Hinge length, shell length/height, and the similarity in size of the shell valves can be used to separate straight-hinged, umbonal, pediveliger, and plantigrade larvae. Quagga × zebra mussel hybrids show characteristics of both parents and are difficult to identify.

  3. Modeling habitat suitability of the invasive clam Corbicula fluminea in a Neotropical shallow lagoon, southern Brazil

    Directory of Open Access Journals (Sweden)

    T. C. L. Silveira

    Full Text Available Abstract This study aimed to model the habitat suitability for an invasive clam Corbicula fluminea in a coastal shallow lagoon in the southern Neotropical region (–30.22, –50.55. The lagoon (19km2, maximum deep 2.5m was sampled with an Ekman dredge in an orthogonal matrix comprising 84 points. At each sampling point, were obtained environmental descriptors as depth, organic matter content (OMC, average granulometry (Avgran, and the percentage of sand (Pcsand. Prediction performance of Generalized Linear Models (GLM, Generalized Additive Models (GAM and Boosted Regression Tree (BRT were compared. Also, niche overlapping with other native clam species (Castalia martensi, Neocorbicula limosa and Anodontites trapesialis was examined. A BRT model with 1400 trees was selected as the best model, with cross-validated correlation of 0.82. The relative contributions of predictors were Pcsand-42.6%, OMC-35.8%, Avgran-10.9% and Depth-10.8%. Were identified that C. fluminea occur mainly in sandy sediments with few organic matter, in shallow areas nor by the shore. The PCA showed a wide niche overlap with the native clam species C. martensi, N. limosa and A. trapesialis.

  4. First record of Corbicula fluminalis (Müller, 1774 in Lake Garda (Italy, living in sympatry with Corbicula fluminea (Müller, 1774

    Directory of Open Access Journals (Sweden)

    Cristina CAPPELLETTI

    2009-02-01

    Full Text Available The first record of Corbicula fluminalis (Müller, 1774 (Mollusca: Bivalvia: Veneroidea: Corbiculidae in Lake Garda (Italy is presented. This clam was observed in July 2008 along the lake shore, with a high number of shells; sampling of lake sediment revealed the presence of live specimens. C. fluminea (Müller, 1774 has already been recorded in Lake Garda since 2002. The need for further studies on the presence and the spread of the two clams and the biodiversity of the invertebrate community of the lake is underlined, in relation to recent records of other invasive species, such as Dikerogammarus villosus (Sowinsky, 1894.

  5. Nanostructure and crystallography of aberrant columnar vaterite in Corbicula fluminea (Mollusca).

    Science.gov (United States)

    Frenzel, Max; Harrison, Richard J; Harper, Elizabeth M

    2012-04-01

    Both the crystallographic and nanostructural organisation of aberrant columnar vaterite occurring in Corbicula fluminea were characterised in detail for the first time using electron microscopic and X-ray powder diffraction techniques. At the millimetre scale, only a confinement of the otherwise randomly oriented c-axis to the growth surface is observed. Domains of 100 or more individual vaterite columns with common c-axis orientation exist within this disordered material. Each column behaves as a single crystal on the scale of EBSD measurements, but is internally composed of smaller irregularly shaped and slightly misaligned crystalline units (0.3-1.3μm in dimension). These are in turn partitioned by porous boundaries into rounded nanodomains, up to 600nm in size. The geometry of the nanodomains and their respective boundaries might suggest formation by the accretion of vesicles. In addition to crystallographic textures, this observation indicates formation under significant biological control with wider implications for possible causes of the condition.

  6. Rare earth elements in the aragonitic shell of freshwater mussel Corbicula fluminea and the bioavailability of anthropogenic lanthanum, samarium and gadolinium in river water

    Energy Technology Data Exchange (ETDEWEB)

    Merschel, Gila, E-mail: g.merschel@jacobs-university.de; Bau, Michael

    2015-11-15

    High-technology metals — such as the rare earth elements (REE) — have become emerging contaminants in the hydrosphere, yet little is known about their bioavailability. The Rhine River and the Weser River in Germany are two prime examples of rivers that are subjected to anthropogenic REE input. While both rivers carry significant loads of anthropogenic Gd, originating from contrast agents used for magnetic resonance imaging, the Rhine River also carries large amounts of anthropogenic La and lately Sm which are discharged into the river from an industrial point source. Here, we assess the bioavailability of these anthropogenic microcontaminants in these rivers by analyzing the aragonitic shells of the freshwater bivalve Corbicula fluminea. Concentrations of purely geogenic REE in shells of comparable size cover a wide range of about one order of magnitude between different sampling sites. At a given sampling site, geogenic REE concentrations depend on shell size, i.e. mussel age. Although both rivers show large positive Gd anomalies in their dissolved loads, no anomalous enrichment of Gd relative to the geogenic REE can be observed in any of the analyzed shells. This indicates that the speciations of geogenic and anthropogenic Gd in the river water differ from each other and that the geogenic, but not the anthropogenic Gd is incorporated into the shells. In contrast, all shells sampled at sites downstream of the industrial point source of anthropogenic La and Sm in the Rhine River show positive La and Sm anomalies, revealing that these anthropogenic REE are bioavailable. Only little is known about the effects of long-term exposure to dissolved REE and their general ecotoxicity, but considering that anthropogenic Gd and even La have already been identified in German tap water and that anthropogenic La and Sm are bioavailable, this should be monitored and investigated further. - Highlights: • Corbicula fluminea shells are bioarchives of dissolved geogenic REE in

  7. Oxidative stress and histological changes following exposure to diamond nanoparticles in the freshwater Asian clam Corbicula fluminea (Müller, 1774)

    Energy Technology Data Exchange (ETDEWEB)

    Cid, Antonio [REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnología, Centro de Química Fina e Biotecnología, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Picado, Ana; Correia, José Brito [LNEG-Laboratório Nacional de Energia e Geologia, I.P. Estrada do Paço do Lumiar 22, 1649-038 Lisboa (Portugal); Chaves, Rúben; Silva, Héber [Centro de Investigação Interdisciplinar Egas Moniz, Instituto Superior de Ciências da Saúde Egas Moniz, 2825-511 Caparica (Portugal); Caldeira, Jorge [REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnología, Centro de Química Fina e Biotecnología, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Centro de Investigação Interdisciplinar Egas Moniz, Instituto Superior de Ciências da Saúde Egas Moniz, 2825-511 Caparica (Portugal); Alves de Matos, António P. [Centro de Investigação Interdisciplinar Egas Moniz, Instituto Superior de Ciências da Saúde Egas Moniz, 2825-511 Caparica (Portugal); Centro de Estudos do Ambiente e do Mar (CESAM/FCUL)—Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa (Portugal); and others

    2015-03-02

    Highlights: • We assess the toxicity of NDs in the bivalve Corbiculafluminea. • Exposure to NDs cause a stress oxidative response. • Stress oxidative enzymes increase following exposure to nanodiamonds. • Increase in lipid peroxidation suggests damage in cells membranes. • Histopathology reveals alterations in digestive gland cells. - Abstract: Recently, the scientific community became aware of the potential ability of nanoparticles to cause toxicity in living organisms. Therefore, many of the implications for aquatic ecosystems and its effects on living organisms are still to be evaluated and fully understood. In this study, the toxicity of nanodiamonds (NDs) was assessed in the freshwater bivalve (Corbicula fluminea) following exposure to different nominal concentrations of NDs (0.01, 0.1, 1, and 10 mg l{sup −1}) throughout 14 days. The NDs were characterized (gravimetry, pH, zeta potential, electron microscopy, and atomic force microscopy) confirming manufacturer information and showing NDs with a size of 4–6 nm. Oxidative stress enzymes activities (glutathione-S-transferase, catalase) and lipid peroxidation were determined. The results show a trend to increase in GST activities after seven days of exposure in bivalves exposed to NDs concentrations (>0.1 mg l{sup −1}), while for catalase a significant increase was found in bivalves exposed from 0.01 to 1.0 mg l{sup −1} following an exposure of 14 days. The histological analysis revealed alterations in digestive gland cells, such as vacuolization and thickening. The lipid peroxidation showed a trend to increase for the different tested NDs concentrations which is compatible with the observed cellular damage.

  8. Biodynamic modeling of PCB uptake by Macoma balthica and Corbicula fluminea from sediment amended with activated carbon

    Science.gov (United States)

    McLeod, Pamela B.; Luoma, S.N.; Luthy, R.G.

    2008-01-01

    Activated carbon amendment was assessed in the laboratory as a remediation strategy for freshwater sediment contaminated with polychlorinated biphenyls (PCBs) from the Grasse River (near Massena, NY). Three end points were evaluated: aqueous equilibrium PCB concentration, uptake into semipermeable membrane devices (SPMDs), and 28-day bioaccumulation in the clam Corbicula fluminea. PCB uptake by water, SPMDs, and clams followed similar trends, with reductions increasing as a function of carbon dose. Average percent reductions in clam tissue PCBs were 67, 86, and 95% for activated carbon doses of 0.7, 1.3, and 2.5% dry wt, respectively. A biodynamic model that incorporates sediment geochemistry and dietary and aqueous uptake routes was found to agree well with observed uptake by C. fluminea in our laboratory test systems. Results from this study were compared to 28-day bioaccumulation experiments involving PCB-contaminated sediment from Hunters Point Naval Shipyard (San Francisco Bay, CA) and the clam Macoma balthica. Due to differences in feeding strategy, M. balthica deposit-feeds whereas C. fluminea filter-feeds, the relative importance of the aqueous uptake route is predicted to be much higher for C. fluminea than for M. balthica. Whereas M. balthica takes up approximately 90% of its body burden through sediment ingestion, C. fluminea only accumulates approximately 45% via this route. In both cases, results strongly suggest that it is the mass transfer of PCBs from native sediment to added carbon particles, not merely reductions in aqueous PCB concentrations, that effectively reduces PCB bioavailability and uptake by sediment-dwelling organisms. ?? 2008 American Chemical Society.

  9. An experimental approach to assess Corbicula fluminea (Müller, 1774) resistance to osmotic stress in estuarine habitats

    Science.gov (United States)

    Ferreira-Rodríguez, Noé; Pardo, Isabel

    2016-07-01

    Corbicula fluminea arrived in the Miño Estuary in 1989 and, from there, colonized more than 150 km upstream. Our aim was to test the capacity of C. fluminea to cope with osmotic stress conditions previously to invade new freshwater habitats through estuaries. Based on previously collected information, the experiment aims to study the response of the species to marine osmotic stress, evaluated by survival and behaviour. Experiments determined the resistance by the species to various levels of osmotic stress, and recovery time after exposure to high salinity levels, representative of the temporal and spatial salinity variation existing in the estuary. Under osmotic stress the semi-maximum response was reached after 19 days exposure. The species tolerance range, measured by individual maintained activity, was at salinity ∼20 when exposed to winter temperatures, while when animals were exposed to summer ones its tolerance was reduced to salinity lower than 15. C. fluminea show a large physiological flexibility to cope with salinity variations in estuaries. In summer, the temperature increases the metabolic rate thus making the species more vulnerable to osmotic stress exposure. These findings are relevant to preventing new invasions through ship ballast waters ensuring complete mortality if individuals are retained for >26 days.

  10. Sodium Gill Potential as a Tool to Monitor Valve Closure Behavior in Freshwater Clam Corbicula fluminea in Response to Copper

    Directory of Open Access Journals (Sweden)

    Wei-Yu Chen

    2008-09-01

    Full Text Available Valve closure behavior in freshwater clam Corbicula fluminea is a biologically sensitive endpoint. The purpose of this paper was to derive an electrophysiological response model of C. fluminea to assess copper (Cu-sodium (Na interactions in gill membrane, whereby valve closure behavior and Cu toxicity could be monitored. The proposed model was based on the integration of Cu bioavailability, Na and Cu internalizations, and electrochemically-based gill potentials. Based on Na active transport under non-equilibrium conditions, predicted gill potential of -8.2 mV agreed reasonably well with published the measured transepithelial potential of -7 mV in C. fluminea. Our proposed framework captured the general features observed in model applications including: (i 50% inhibitory Cu2+ activities for Na membrane potential (ENa and uptake rate (JNa were estimated to be 0.072 and 0.043 mM, respectively, with a stoichiometry of 3Cu2+: 1ENa and 1JNa; (ii the external Cu2+-dependent internal Na concentration could be parsimoniously estimated, and (iii the site-specific clam gill potentials could be monitored. Here we provided a new approach to monitor waterborne metal toxicity to reduce the nationwide economic losses due to bans on harvesting of contaminated clam and the potential risks to the health of clams.

  11. Long-Term Acclimation to Different Thermal Regimes Affects Molecular Responses to Heat Stress in a Freshwater Clam Corbicula Fluminea

    Science.gov (United States)

    Falfushynska, Halina I.; Phan, Tuan; Sokolova, Inna M.

    2016-12-01

    Global climate change (GCC) can negatively affect freshwater ecosystems. However, the degree to which freshwater populations can acclimate to long-term warming and the underlying molecular mechanisms are not yet fully understood. We used the cooling water discharge (CWD) area of a power plant as a model for long-term warming. Survival and molecular stress responses (expression of molecular chaperones, antioxidants, bioenergetic and protein synthesis biomarkers) to experimental warming (20–41 °C, +1.5 °C per day) were assessed in invasive clams Corbicula fluminea from two pristine populations and a CWD population. CWD clams had considerably higher (by ~8–12 °C) lethal temperature thresholds than clams from the pristine areas. High thermal tolerance of CWD clams was associated with overexpression of heat shock proteins HSP70, HSP90 and HSP60 and activation of protein synthesis at 38 °C. Heat shock response was prioritized over the oxidative stress response resulting in accumulation of oxidative lesions and ubiquitinated proteins during heat stress in CWD clams. Future studies should determine whether the increase in thermal tolerance in CWD clams are due to genetic adaptation and/or phenotypic plasticity. Overall, our findings indicate that C. fluminea has potential to survive and increase its invasive range during warming such as expected during GCC.

  12. Impact of hypoxia on hemolymph contamination by uranium in an aquatic animal, the freshwater clam Corbicula fluminea

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Damien [Universite Bordeaux 1, CNRS, UMR 5805 EPOC, Place du Dr Peyneau, 33120 Arcachon (France)], E-mail: d.tran@epoc.u-bordeaux1.fr; Massabuau, Jean-Charles [Universite Bordeaux 1, CNRS, UMR 5805 EPOC, Place du Dr Peyneau, 33120 Arcachon (France)], E-mail: jc.massabuau@epoc.u-bordeaux1.fr; Garnier-Laplace, Jacqueline [Laboratoire de Radioecologie et Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat. 186, BP3, 13115 Saint Paul-Lez-Durance, Cedex (France)], E-mail: Jacqueline.Garnier-Laplace@irsn.fr

    2008-12-15

    Multi-stress situations are a major question and low-oxygenated waters (hypoxia) are a growing problem. Importantly, hypoxia stimulates the ventilatory flow rate in aquatic animals and this increases gill exposure to contaminants. Surprisingly, in the freshwater clam Corbicula fluminea, this is associated with increased bioaccumulation of uranium in gills but not in deep tissues. We searched for an explanation by analyzing hemolymph U-transport in Corbicula exposed to 0.36 {mu}M dissolved uranium at various O{sub 2}-levels for 10 days. In hypoxia, one observed an increased U concentration in the arterial hemolymph flowing from gills to tissues but this was not associated with an increased U concentration in the venous hemolymph nor in the other tissues. We conclude that the cardiac flow rate must have decreased to explain this absence of over-accumulation. In addition to its already known deleterious effects, uranium can thus deeply impair cardiac flow rate in exposed aquatic animals during multi-stress exposures. - Uranium contamination enhanced by hypoxia can deeply impair circulatory hemolymph flow in aquatic animals.

  13. Bioconcentration and biotransformation of [¹⁴C]methoxychlor in the brackish water bivalve Corbicula japonica.

    Science.gov (United States)

    Masuda, Minoru; Ohyama, Kazutoshi; Hayashi, Osamu; Satsuma, Koji; Sato, Kiyoshi

    2011-09-01

    To obtain basic information on the metabolic fate of xenobiotics in the brackish water, bivalve Corbicula japonica, bioconcentration and biotransformation experiments were performed using methoxychlor (MXC) as a model compound. Bivalves were exposed to [ring-U-¹⁴C]MXC (10 µg L⁻¹) for 28 days under semi-static conditions followed by a 14-day depuration phase. The ¹⁴C concentration in the bivalves rapidly increased and reached a steady state after exposure for 7 days (BCFss = 2010); however, it rapidly decreased with a half-life of 2.2 days in the depuration phase. Mono- and bis-demethylated MXC, and their corresponding sulphate conjugates, were identified as minor metabolites. No glycoside conjugates (including glucuronide and glucoside) were detected. Despite this biotransformation system, bivalves were found to excrete retained MXC mostly unchanged although its relatively hydrophobic nature.

  14. Rare earth elements in the aragonitic shell of freshwater mussel Corbicula fluminea and the bioavailability of anthropogenic lanthanum, samarium and gadolinium in river water.

    Science.gov (United States)

    Merschel, Gila; Bau, Michael

    2015-11-15

    High-technology metals - such as the rare earth elements (REE) - have become emerging contaminants in the hydrosphere, yet little is known about their bioavailability. The Rhine River and the Weser River in Germany are two prime examples of rivers that are subjected to anthropogenic REE input. While both rivers carry significant loads of anthropogenic Gd, originating from contrast agents used for magnetic resonance imaging, the Rhine River also carries large amounts of anthropogenic La and lately Sm which are discharged into the river from an industrial point source. Here, we assess the bioavailability of these anthropogenic microcontaminants in these rivers by analyzing the aragonitic shells of the freshwater bivalve Corbicula fluminea. Concentrations of purely geogenic REE in shells of comparable size cover a wide range of about one order of magnitude between different sampling sites. At a given sampling site, geogenic REE concentrations depend on shell size, i.e. mussel age. Although both rivers show large positive Gd anomalies in their dissolved loads, no anomalous enrichment of Gd relative to the geogenic REE can be observed in any of the analyzed shells. This indicates that the speciations of geogenic and anthropogenic Gd in the river water differ from each other and that the geogenic, but not the anthropogenic Gd is incorporated into the shells. In contrast, all shells sampled at sites downstream of the industrial point source of anthropogenic La and Sm in the Rhine River show positive La and Sm anomalies, revealing that these anthropogenic REE are bioavailable. Only little is known about the effects of long-term exposure to dissolved REE and their general ecotoxicity, but considering that anthropogenic Gd and even La have already been identified in German tap water and that anthropogenic La and Sm are bioavailable, this should be monitored and investigated further.

  15. Bioaccumulation of polychlorinated biphenyls and metals from contaminated sediment by freshwater prawns, Macrobrachium rosenbergii and clams, Corbicula fluminea

    Energy Technology Data Exchange (ETDEWEB)

    Tatem, H.E.

    1986-02-01

    Freshwater prawns, Macrobrachium rosenbergii, and clams, Corbicula Fluminea, were exposed for 48 or 50 days to three concentrations of a river sediment that contained environmental contaminants such as polychlorinated biphenyls (PCBs) and metals. The PCB sediment bioaccumulation factors (BAF) for prawns ranged from 0.11 to 0.90 for 1242 and 0.20 to 2.40 for 1254, and were highest for animals exposed to 10% sediment. Exposed clams also accumulated PCBs (1242 + 1254) from the sediment. Sediment BAFs for clams were 0.54 to 12.52 and were highest for animals exposed to 10% sediment. Analyses of clams for metals showed lead (Pb) in exposed animals at higher concentrations compared with controls. Bioaccumulation of Pb differed from PCB in that the Pb concentrations did not increase over time and concentrations were higher among animals exposed to 10% sediment compared to animals exposed to 100% sediment. Sediment 11-80 contained 99 mg/kg of Pb while exposed animals, at 48 days, contained approximately 2.2 mg/kg Pb. Analysis of clams for cadmium (Cd) showed exposed animals contained less Cd than controls.

  16. Isolation of microsatellite loci and population genetic structure analysis of wild Corbicula fluminea in Hongze Lake%河蚬微卫星引物筛选及洪泽湖野生群体遗传结构分析

    Institute of Scientific and Technical Information of China (English)

    丁怀宇; 姜虎成; 冯建彬; 孙骥; 李家乐

    2011-01-01

    利用磁珠富集法筛选了河蚬10对中高度多态性的微卫星引物,并分析了洪泽湖河蚬4个野生群体的遗传结构.结果表明,每个群体至少有4个位点经Bonferroni校正后显示杂合不足,显著偏离了Hardy -Weinberg平衡(P<0.013);4个群体平均期望杂合度均大于0.752,显示出较高的遗传多样性水平,蒋坝、临淮群体遗传多样性高于高良涧和老子山群体;突变-漂移平衡分析结果显示,4个群体在IAM模型下偏离了突变-漂移平衡,高良涧群体在TPM模型下偏离了突变-漂移平衡,且表现杂合过剩,说明少数群体即将或曾经经历瓶颈效应,群体数量已出现波动;群体间AMOVA分析表明,洪泽湖河蚬群体间遗传分化程度较低(FST=0.017 7<0.05),仅有1.77%的变异来自群体间,并没有形成显著的遗传结构,在种质资源保护和管理上可视作一个单元,这为河蚬种质资源保护和合理开发利用提供了理论指导.%Asian clam( Corbicula fluminea) is a commercially important freshwater bivalve in South and East Asia. However,food clam mainly comes from the wild resources,and the natural populations have declined greatly and rapidly due to overfishing and natural habitats degradation. In China, the germplasm resource protection zone of C. Fluminea has been set up in Hongze Lake to protect the natural resources. In this paper, genetic structure of four wild C. Fluminea populations in Hongze Lake was analysized using ten polymorphic microsatellite DNA loci isolated and characterized by magnetic beads enrichment methods. The results showed that at least four of the loci were observed to have significant heterozygosity deficiency and obvious deviations from Hardy-Weinberg equilibrium(P<0.013) after Bonferroni correction in the four populations. Although values of expected heterozygosity were all above 0.752 and displayed high genetic diversity in the four populations,the level of genetic diversity fluctuated

  17. First genotoxicity study of Paraná river water from Argentina using cells from the clam Corbicula fluminea (Veneroida Corbiculidae and Chinese hamster (Cricetulus griseus Rodentia, Cricetidae K1 cells in the comet assay

    Directory of Open Access Journals (Sweden)

    Jacqueline D. Caffetti

    2008-01-01

    Full Text Available High concentrations of xenobiotics from urban and industrial wastes have contributed to the contamination of many aquatic environments. We used the comet assay to evaluate the genotoxic potential of water collected from the River Paraná, which receives a great deal of waste, at three points (Puerto Piray, Eldorado and Montecarlo in the Misiones Province of Argentina. The in vivo comet assay used 40 freshwater clams (Corbicula fluminea while the in vitro comet assay used Chinese hamster (Cricetulus griseus K1 cell (CHO-K1 cultures with the mutagen ethyl methanesulfonate (EMS as the positive control and phosphate buffered saline (PBS as the negative control. Both assays showed statistically significant differences between the three sampling sites in relation to the negative control, the results of this preliminary study indicating that at these three sites water from the Paraná River presents genotoxic potential.

  18. 河蚬糖蛋白体外免疫功能研究%Studies on the Immune Functions in Vitro of Glycoprotein from Corbicula Fluminea

    Institute of Scientific and Technical Information of China (English)

    杜华英; 徐明生; 曾婷婷; 尹忠平

    2012-01-01

    Objective: To investigate the effects of glycoprotein from corbicula fluminea on immun function of mice in vitro, Method: We separated mice lymphocytes and phagocytic with aseptic manipulation and cultivated them with gross glycoprotein and CFP (5 μg/mL, 25 μg/mL, 125 μg/mL, 625 μg/mL). Then the effect of gross glycoprotein and CFP on the proliferative activity of mice lymphocytes and phagocytosis of mouse peritoneal macrophage were measured by using MTT method. Results; A dosage of 125 μg/mL gross glycoprotein and different CFP concentrations could enhance the splenic lymphocytes multiplication when no mitogen (ConA and LPS) was added, but when the cells were induced with ConA and LPS, the stimulation indexes of all the gross glycoprotein and different CFP concentration groups were higher that those of the group without mitogen. Meanwhile, a dosage of 125 μg/mL gross glycoprotein and different CFP concentrations could accelerate the peritoneal macrophage phagocytize neutral red, and the phagocytic ability was a profile of the dosage dependent. Conclusion; The gross glycoprotein and CFP could enhance immune function in vitro, and the effect of the CFP is the better.%目的:研究河蚬糖蛋白对小鼠体外免疫功能的影响.方法:无菌分离小鼠脾淋巴细胞和腹腔巨噬细胞,与不同质量浓度(5、25、125、625 μg/mL)的河蚬粗糖蛋白和高纯度糖蛋白CFP共同培养,采用MTT法测定其对淋巴细胞增殖和腹腔巨噬吞噬能力的影响.结果:在无有丝分裂原诱导下,125 μg/mL的粗糖蛋白和4个浓度的CFP都有促进脾淋巴细胞的作用.在有丝分裂原刺激下,粗糖蛋白和CFP的刺激指数都比未加有丝分裂原时增大.125 μg/mL粗糖蛋白和4个浓度的CFP都有提高巨噬细胞的吞噬能力,且2种河蚬糖蛋白都表现出一定的剂量效应关系.结论:河蚬粗糖蛋白和CFP均有免疫增强活性,其中CFP的活性较强.

  19. Selenium Bioaccumulation and Its Influence on Antioxidant System in Corbicula fluminea%硒在河蚬体内的富集及其对河蚬的氧化应激

    Institute of Scientific and Technical Information of China (English)

    王文娜; 王沛芳; 常虹; 尹亚云; 王永泉; 张微敏

    2014-01-01

    Corbicula fluminea has showed potential to be a bio-indicator of sediment pollution. A laboratory experiment was undertaken to investigate the bioaccumulation of selenium(Se)and its influence on antioxidant system and peroxidation product in the visceral mass of C. fluminea under exposure of 14 days. Sediments, obtained from Lake Taihu, were spiked with sodium selenite. The bioaccumulation of Se in C. fluminea was linearly related to Se concentrations in the sediments. The bio-concentration factor(BCF)had a power function relationship with Se concentrations. The color of the visceral mass of C. fluminea gradually became blackened with increasing Se concentrations. The ac-tivities of catalase(CAT), glutathione peroxidase(GPx)and superoxide dismutase(SOD)showed“increase and then decrease”pattern as Se concentrations increased. GPx and CAT were more sensitive to Se contamination than SOD. The maximum activities of CAT and GPx were observed both at 0.609 mg·kg-1 of Se exposure concentration, being 2.84 times and 4.82 times of the control. SOD activity was greatest at 1.638 mg Se·kg-1, which was 2.87 times of the control. The contents of MDA didn′t show consistent responses to Se concentrations. These results indicate that C. fluminea could be used as an indicator of Se pollution in water sediments.%通过实验室模拟的方法,以河蚬(Corbicula fluminea)为实验生物,研究了太湖沉积物中硒在河蚬体内的富集及其对河蚬抗氧化系统和过氧化产物的影响。结果显示:硒在河蚬体内的富集与沉积物中硒浓度呈线性相关,生物富集系数(Bioconcentration factor, BCF)与暴露浓度之间呈幂函数关系;随着硒暴露浓度的增大,河蚬受毒害,内脏团颜色加深;硒对河蚬内脏团的几种酶活性和过氧化产物表现出不同程度的影响。酶活性随硒浓度增大均表现为先升高后降低的趋势,其中谷胱甘肽过氧化物酶(GPx)和过氧化氢酶

  20. Assessment of ametryn contamination in river water, river sediment, and mollusk bivalves in São Paulo state, Brazil.

    Science.gov (United States)

    Jacomini, Analu Egydio; de Camargo, Plínio Barbosa; Avelar, Wagner Eustáquio Paiva; Bonato, Pierina Sueli

    2011-04-01

    São Paulo state, Brazil, is one of the main areas of sugar cane agriculture in the world. Herbicides, in particular, ametryn, are extensively used in this extensive area, which implies that this herbicide is present in the environment and can contaminate the surface water by running off. Thereby, residues of ametryn were analyzed in samples of river water an river sediment and in freshwater bivalves obtained from the rivers Sapucaí, Pardo and Mogi-Guaçu in São Paulo State, Brazil. Samples were taken in the winter of 2003 and 2004 in two locations in each river. The specimens of freshwater bivalves collected and analyzed were Corbicula fluminea, an exotic species, and Diplodon fontaineanus, a native species. Additionally, the evaluation of the ability of bioconcentration and depuration of ametryn by the freshwater bivalve Corbicula fluminea was also performed. Ametryn concentrations in the samples were measured by liquid chromatography coupled to mass spectrometry. Residues of ametryn in water (50 ng/L) and in freshwater bivalves (2-7 ng/g) were found in the Mogi-Guaçu River in 2004, and residues in river sediments were found in all rivers in 2003 and 2004 (0.5-2 ng/g). The observation of the aquatic environment through the analysis of these matrixes, water, sediment, and bivalves, revealed the importance of the river sediment in the accumulation of the herbicide ametryn, which can contaminate the biota.

  1. Phylogenetic analysis of freshwater mussel corbicula regularis by 18s rRNA gene sequencing

    Directory of Open Access Journals (Sweden)

    Magare V N

    2015-04-01

    Full Text Available Corbicula regularis is a freshwater mussel found in the Indian sub-continent. In the present study, phylogenetic characterization of this important bivalve was attempted using 18S ribosomal RNA gene markers. Genomic DNA was extracted and 18S rRNA gene was amplified by universal primers. The amplification product was sequenced and compared with the nucleotide databases available online to evaluate phylogenetic relationship of the animal under study. Results indicated that 18S rRNA gene sequences of C. regularis showed high degree of similarity to another freshwater mussel, C. fluminea. This work constitutes the first ever sequence deposition of the C. regularis in the nucleotide databases highlighting the usefulness of 18S ribosomal gene markers for phylogenetic analysis.

  2. Suspended material availability and filtration-biodeposition processes performed by a native and invasive bivalve species in streams

    Science.gov (United States)

    Atkinson, C.L.; First, M.R.; Covich, A.P.; Opsahl, S.P.; Golladay, S.W.

    2011-01-01

    Unionid mussels are among the most threatened group of freshwater organisms globally. They are known for their ability to filter food particles from flowing and standing waters. However, invasive bivalve species, such as the Asian clam (Corbicula fluminea) in North America, have the potential to overlap in feeding and potentially out-compete the native species. Yet, the feeding preferences of unionid mussels and C. fluminea are incompletely understood. We hypothesized that Elliptio crassidens (native) and C. fluminea (invasive) would select for specific organic components present within seston. We examined changes in seston (dry mass and ash-free dry mass) resulting from bivalve feeding activity for three size classes of material that were isolated using gravimetric filtration. The treatments were also sub-sampled for flow cytometry (FC) which separated the suspended materials in the stream water into five categories: detritus, heterotrophic bacteria, picoautotrophs, nanoautotrophs, and heterotrophic nanoeukaryotes. Our results indicated that both species of bivalve showed preferences for organic and living materials. E. crassidens preferentially filtered nanoeukaryotes, whose decreases were associated with an increase in bacteria. In contrast, C. fluminea preferred smaller materials through selective filtration of picoautotrophs. In addition, both species increased the concentration of large materials toward the end of the experiment because of the suspension of their pseudofeces biodeposits. To our knowledge, this study is the first to examine grazing by bivalve species on natural stream particulate matter using FC. Our results suggest that native and non-native mussels have different functional roles, which has important implications for organic matter processing and food webs in streams. ?? 2011 Springer Science+Business Media B.V.

  3. Linking terrestrial and estuarine ecosystems: Organic matter sources supporting the high secondary production of a non-indigenous bivalve

    Science.gov (United States)

    The Asian clam Corbicula fluminea is one of the most pervasive species in freshwater ecosystems. Our objective was to characterize the trophic interactions of C. fluminea in the Minho river estuary (NW-Iberian Peninsula, Europe), an estuarine ecosystem in which C. fluminea presen...

  4. First records of Freshwater Bivalves of Ilha Grande National Park, Paraná, Brazil

    Directory of Open Access Journals (Sweden)

    Flávio Henrique Ragonha

    2014-03-01

    Full Text Available The Ilha Grande National Park, Paraná, Brazil, is located in the Upper Paraná River and has characteristics typical of a floodplains. This protected area includes lagoons connected and disconnected to the Paraná River, although the latter also connect during periods of high water level, thus composing a heterogeneous group of lacustrine environments. The enormous potential the flora and fauna diversities are still little known to the region, as can be seen through benthic invertebrates, inclunding bivalves mollusks. The granulometric composition of these floodplain lagoons was formed mainly by mud and very fine sand. Furthermore, organic matter composition was predominantly of fine particulate. The other abiotic factors differed from lagoons located within the island of the park to those located in the left margin of Paraná River. The results demonstrated the importance of abiotic factors such as the physical composition of granulometric texture, organic matter and macrophyte banks, to the establishment of bivalves in these floodplain lagoons. We recorded bivalves of Pisidium (native, Diplodon (native, and Corbicula (invasive. The highest values of Diplodon sp. density were observed at São João/C lake, for Pisidium sterkianum (Pilsbry, 1897 at São João/M lake, and to Jatobá/C lagoon with high density of invasive species Corbicula fluminea (Müller, 1774. This study to obtain conduct the first records of freshwater bivalves in floodplains lagoon in the Ilha Grande National Park, and provides contributions to better understanding the ecology of these mollusks. The recording of native species in the region of Upper Paraná River floodplain after a lomg period without new records, demonstrated the importance of protecting the lagoons of the Ilha Grande National Park as they can be a possible refuge to some species of native freshwater bivalves.

  5. Using biochemical and isotope geochemistry to understand the environmental and public health implications of lead pollution in the lower Guadiana River, Iberia: a freshwater bivalve study.

    Science.gov (United States)

    Company, R; Serafim, A; Lopes, B; Cravo, A; Shepherd, T J; Pearson, G; Bebianno, M J

    2008-11-01

    Lead is a natural component of aquatic ecosystems with no known biological role and is highly toxic. Its toxicity stems from its ability to mimic biologically important metals and to produce membrane damage through lipid peroxidation (LPO). Most lead poisoning symptoms are thought to occur by interfering with an essential enzyme, delta-aminolevulinic acid dehydratase (ALAD), the activity of which is markedly inhibited by lead. The purpose of this work was to study the levels and effects of lead pollution (responses of ALAD and oxidative stress biomarker LPO) in the freshwater bivalve Corbicula fluminea along the lower Guadiana River (Portugal and Spain); a major river system impacted by historic mining pollution and more recent anthropogenic inputs. The results show that the enzymatic activity of ALAD is negatively correlated with the total Pb concentration of the whole tissue suggesting that ALAD has considerable potential as a biomarker of lead exposure in C. fluminea. To identify the sources of lead to which bivalves have been exposed, high precision (206)Pb/(204)Pb, (207)Pb/(204)Pb, (208)Pb/(204)/Pb ratios for C. fluminea confirm that historical mining activities in the Iberian Pyrite Belt are the dominant source of lead pollution in the lower Guadiana River. The isotope patterns however exhibit marked seasonal and geographic variation in response to rainfall and river water management. Locally, other anthropogenic sources of lead have been detected in C. fluminea close to population centres, thus adding to its versatility as a freshwater bio-indicator. Overall, the study highlights the value of natural ecosystems as monitors of water quality and their importance for public health assessment and surveillance.

  6. A review of the occurrence of Corbicula in the Pleistocene of North-West Europe

    NARCIS (Netherlands)

    Meijer, T.; Preece, R.C.

    2000-01-01

    Shells belonging to the bivalve genus Corbicula occur commonly in Pleistocene interglacial deposits in NW Europe. These have usually been identified as C. fluminalis, a modern species described from the Euphrates river, although the veracity of this specific attribution remains equivocal. Corbicula

  7. Patrones de colonización y ecología de poblaciones de dos bivalvos invasores (mejillón cebra Dreissena polymorpha Pallas, 1771 y almeja asiática Corbicula fluminea Müller, 1774 en un tramo lótico del Ebro medio (Castejón, Navarra.

    Directory of Open Access Journals (Sweden)

    MORALES, J., FLECHOSO, F., LIZANA, M., NEGRO, A.

    2013-01-01

    Full Text Available Los bivalvos dulceacuícolas son un componente importante de la ecología fluvial, fundamentalmente por el papel que desempeñan como organismos filtradores y de remoción del sedimento. Además son un grupo zoológico diverso y amenazado a escala global, en el que se incluyen algunas de las especies invasoras más dañinas. El estudio de sus poblaciones es imprescindible para conocer el estado de conservación de las comunidades bentónicas. Para esto se prospectaron 17 parcelas vadeables y 7 escolleras a lo largo de 7,38 km de meandros del río Ebro en Castejón (Navarra, tanto el cauce principal como en brazos secundarios de corriente permanente y/o temporal. El mejillón cebra Dreissena polymorpha Pallas, 1771 se encontró en 7 escolleras y 6 parcelas. El sustrato preferente fueron rocas (85%, donde la densidad resultó 0,31-5,45 mejillones/m2; el 2,6% se hallaron sobre plásticos agrícolas abandonados. En las escolleras sólo el 3,6% de los ejemplares eran juveniles y un 33% tenían una edad > 4 años. La almeja asiática Corbicula fluminea Müller, 1774 se encontró en todas las parcelas. La densidad resultó muy diferente en los tres tipos de ambientes fluviales con valores máximos de 15.100 almejas/m2, lo que constituye un nuevo máximo fluvial en Europa. Se encontraron subpoblaciones de almeja asiática con diferentes estructuras de edad según los ambientes fluviales, además de poblaciones menos numerosas en el brazo principal del río que en los otros tipos. Los resultados muestran que junto a estas especies alóctonas en expansión, con altas tasas de reclutamiento, se encuentra una estructura poblacional muy precaria para las autóctonas, de las cuales únicamente se localizaron 12 náyades vivas y ningún esférido.

  8. A 3D individual-based aquatic transport model for the assessment of the potential dispersal of planktonic larvae of an invasive bivalve.

    Science.gov (United States)

    Hoyer, Andrea B; Wittmann, Marion E; Chandra, Sudeep; Schladow, S Geoffrey; Rueda, Francisco J

    2014-12-01

    The unwanted impacts of non-indigenous species have become one of the major ecological and economic threats to aquatic ecosystems worldwide. Assessing the potential dispersal and colonization of non-indigenous species is necessary to prevent or reduce deleterious effects that may lead to ecosystem degradation and a range of economic impacts. A three dimensional (3D) numerical model has been developed to evaluate the local dispersal of the planktonic larvae of an invasive bivalve, Asian clam (Corbicula fluminea), by passive hydraulic transport in Lake Tahoe, USA. The probability of dispersal of Asian clam larvae from the existing high density populations to novel habitats is determined by the magnitude and timing of strong wind events. The probability of colonization of new near-shore areas outside the existing beds is low, but sensitive to the larvae settling velocity ws. High larvae mortality was observed due to settling in unsuitable deep habitats. The impact of UV-radiation during the pelagic stages, on the Asian clam mortality was low. This work provides a quantification of the number of propagules that may be successfully transported as a result of natural processes and in function of population size. The knowledge and understanding of the relative contribution of different dispersal pathways, may directly inform decision-making and resource allocation associated with invasive species management.

  9. Mercury accumulation in caged Corbicula: rate of uptake and seasonal variation.

    Science.gov (United States)

    Neufeld, Douglas S G

    2010-09-01

    The uptake and seasonal fluctuations of total mercury were followed in caged and uncaged Asiatic clams, Corbicula fluminea, over a 1-year period in South River, Virginia. Mercury was rapidly accumulated in clams transplanted from a nominally uncontaminated site into cages on the contaminated South River, reaching 0.99 microg g(-1) dry mass within the first month. Resident clams moved to cages had higher mercury contents after the first month (2.04 microg g(-1) dry mass) and at all subsequent times in the study. Large monthly fluctuations in mercury were noted for both resident caged and transplant caged clams with a notable peak occurring in early spring (4.31 microg g(-1) dry mass in resident caged clams). Tissue mass of caged clams steadily increased through the winter and early spring. Adjustment of mercury concentrations for tissue mass changes indicated that the changes in mercury contents were primarily due to uptake/release rather than changes in tissue mass (concentration/dilution). The present study demonstrates the utility of using caged Corbicula as mercury biomonitors and illustrates the importance of accounting for large, short-term changes of mercury content in Corbicula when designing long-term biomonitoring studies.

  10. Detection of tdh and trh genes in Vibrio parahaemolyticus isolated from Corbicula moltkiana prime in West Sumatera, Indonesia.

    Science.gov (United States)

    Marlina; Radu, Son; Kqueen, Cheah Yoke; Napis, Suhaimi; Zakaria, Zunita; Mutalib, Sahilah Abd; Nishibuchi, Mitsuaki

    2007-03-01

    The occurrence of Vibrio parahaemolyticus in raw Corbicula moltkiana Prime from Lake Singkarak and Pasar Raya Padang market and in cooked samples in West Sumatera, Indonesia, was studied. Thirteen raw and seven cooked bivalve samples were positive using CHROMAgar Vibrio medium. All 47 V parahaemolyticus isolates were positive for toxR gene but negative for trh. However, 36% (17/47) of V parahaemolyticus strains were positive for tdh gene. Antibiotic profiling showed that 76% and 38% of isolates from raw and cooked bivalves respectively were resistant to ampicillin. Using RAPD-PCR analysis, most of the strains were clustered according to their source of isolation but some of the strains from raw and cooked samples were clustered together. These results indicate that pathogenic V parahaemolyticus isolates are present in Corbicula moltkiana Prime in West Sumatera, Indonesia, suggesting that V parahaemolyticus may also be present in seafood in other regions of Indonesia.

  11. Corbicula fluminea as a Bioaccumulation Indicator Species: A Case Study at the Columbia and Willamette Rivers

    Science.gov (United States)

    2009-06-01

    among stations were explored by overlaying concentrations on the joint cluster- MDS plots ( Biplots ) and by performing Nodal Analysis. Nodal Analysis...appear to have any specific trends and did not vary significantly across the sample locations. Using MDS- clustering biplots (Appendix C), the...conducted using Multidimensional Scaling (MDS). As part of the MDS approach, two-dimensional plots or biplots can be drawn to visualize the clustering

  12. BEHAVIORAL AND PHYSIOLOGICAL RESPONSES OF DAPHNIA MAGNA, CHLORELLA VULGARIS, CORBICULA FLUMINEA, LEPOMIS MACROCHIRUS, AND VIBRO FISCHERI

    Science.gov (United States)

    The research presented here is a continuation of work designed to further the science of available and developing continuous, automated water quality monitors and how they may be most effectively deployed in a watershed management plan and/or water quality early warning system (W...

  13. Absence of sterols constrains food quality of cyanobacteria for an invasive freshwater bivalve.

    Science.gov (United States)

    Basen, Timo; Rothhaupt, Karl-Otto; Martin-Creuzburg, Dominik

    2012-09-01

    The accumulation of cyanobacterial biomass may severely affect the performance of aquatic consumers. Here, we investigated the role of sterols in determining the food quality of cyanobacteria for the invasive clam Corbicula fluminea, which has become a common benthic invertebrate in many freshwater ecosystems throughout the world. In standardized growth experiments, juvenile clams were fed mixtures of different cyanobacteria (Anabaena variabilis, Aphanothece clathrata, Synechococcus elongatus) or sterol-containing eukaryotic algae (Cryptomonas sp., Nannochloropsis limnetica, Scenedesmus obliquus). In addition, the cyanobacterial food was supplemented with different sterols. We provide evidence that somatic growth of C. fluminea on cyanobacterial diets is constrained by the absence of sterols, as indicated by a growth-enhancing effect of sterol supplementation. Thus, our findings contribute to our understanding of the consequences of cyanobacterial mass developments for benthic consumers and highlight the importance of considering sterols as potentially limiting nutrients in aquatic food webs.

  14. Uranium(VI) speciation: modelling, uncertainty and relevance to bioavailability models. Application to uranium uptake by the gills of a freshwater bivalve; Speciation de l'uranium(6), modelisation, incertitude et implication pour les modeles de biodisponibilite. Application a l'accumulation dans les branchies d'un bivalve d'eau douce

    Energy Technology Data Exchange (ETDEWEB)

    Denison, F.H

    2004-07-01

    The effects of varying solution composition on the interactions between uranium(VI) and excised gills of the freshwater bivalve Corbicula fluminea have been investigated in well defined solution media. A significant reduction in the uptake of uranium was observed on increasing the concentrations of the uranium complexing ligands citrate and carbonate. Saturation kinetics as a function of uranium concentration at a pH value of 5.0 were observed, indicating that the uptake of uranium is a facilitated process, probably involving one or several trans-membrane transport systems. A relatively small change in the uptake of uranium was found as a function of pH (factor of ca. 2), despite the extremely large changes to the solution speciation of uranium within the range of pH investigated (5.0 - 7.5). A comprehensive review of the thermodynamic data relevant to the solution composition domain employed for this study was performed. Estimates of the uncertainties for the formation constants of aqueous uranium(VI) species were integrated into a thermodynamic database. A computer program was written to predict the equilibrium distribution of uranium(VI) in simple aqueous systems, using thermodynamic parameter mean-values. The program was extended to perform Monte Carlo and Quasi Monte Carlo uncertainty analyses, incorporating the thermodynamic database uncertainty estimates, to quantitatively predict the uncertainties inherent in predicting the solution speciation of uranium. The use of thermodynamic equilibrium modelling as a tool for interpreting the bioavailability of uranium(VI) was investigated. Observed uranium(VI) uptake behaviour was interpreted as a function of the predicted changes to the solution speciation of uranium. Different steady-state or pre-equilibrium approaches to modelling uranium uptake were tested. Alternative modelling approaches were also tested, considering the potential changes to membrane transport system activity or sorption characteristics on

  15. Assimilation of terrigenous organic matter via bacterial biomass as a food source for a brackish clam, Corbicula japonica (Mollusca: Bivalva)

    Science.gov (United States)

    Yamanaka, Toshiro; Mizota, Chitoshi; Maki, Yonosuke; Matsumasa, Masatoshi

    2013-07-01

    Corbicula japonica collected from the Kitakami River estuary, northeastern Japan, showed lower δ34S values in soft-body parts (+1.7 to +11.0‰) than the ambient seawater sulfate sulfur (+21‰), and this value gradually decreased at successive sites up to 15.8 km upstream from the river mouth. Previous study using carbon and nitrogen isotopes suggests that the bivalve nonselectively assimilates particulate organic matter of marine and terrestrial origin by filter feeding. This pattern in δ34S values may indicate a considerable contribution of a food source derived from terrigenous organic matter, which has low δ34S values close to 0‰, and the bivalve has been reported to have cellulase and hemicellulase activities. Unique fatty acids (iso 17:0 and anteiso 17:0 acids), both characteristic of sulfate-reducing bacteria, were observed in the salt-free, soft-body parts of the bivalve. The concentration of monounsaturated fatty acids, possibly derived from bacteria, was also high. Trace amounts of a polyunsaturated fatty acid (20:5ω3) specific to dinoflagellates were detected. In Corbicula habitats, reductive sandy layers with ample sulfides that were sporadically intercalated into the oxidative sandy sediment were often observed. The stable isotopic signatures of sediment sulfides (acid-volatile sulfide) and associated pore-water sulfates were -8.9 to +8.6‰ and +22.4 to +26.3‰, respectively, indicating the existence of bacterial sulfate-reducing activity and thiobios biomass. These isotopic signatures of the sediment, with the fatty acid composition of the bivalve, confirm the importance of a food source derived from bacteria belonging to the thiobios in the substrate sediments via pedal feeding, rather than direct digestion of terrigenous organic matter, in this estuarine ecosystem.

  16. BEHAVIORAL AND PHYSIOLOGICAL RESPONSES OF DAPHNIA MAGNA, CHLORELLA VULGARIS, CORBICULA FLUMINEA, AND LEPOMIS MACROCHIRUS TO COPPER AND CYANIDE

    Science.gov (United States)

    The research presented here was designed to further the science of available and developing continuous, automated water quality monitors and how they may be most effectively deployed in a watershed management plan and/or water quality early warning system (WQEWS). Source waters ...

  17. Active biomonitoring with Corbicula for USEPA priority pollutant and metal sources in the Anacostia River (DC, Maryland, USA).

    Science.gov (United States)

    Phelps, Harriette L

    2016-07-01

    The freshwater Anacostia River watershed (Maryland, DC, USA) was surveyed for the sources of bioavailable US Environmental Protection Agency (USEPA) Priority Pollutants and toxic metals by active biomontoring (ABM) using the freshwater Asiatic clam Corbicula fluminea. The Anacostia River is a 456 km(2) tributary of the tidal freshwater Potomac River that includes the city of Washington, DC where edible fish are highly contaminated with PCBs and chlordane. From 1999 to 2011, Corbicula were collected for ABM from a Potomac reference site and translocated in cages placed at 45 sites in the tidal and nontidal Anacostia watershed. Minimum clam mortality and maximum contaminant bioaccumulation was with 2-week translocation. The clam tissues (28-50) were combined at sites and analyzed by TestAmerica for 66 USEPA Priority Pollutants plus technical chlordane, benz(e) pyrene, and 6 metals (As, Cd, Cr, Cu, Fe, Pb). Tissue contaminants reflected water, not sediment, levels. To compare sites, all contaminant data above detection or reference were grouped as total metals (TMET), total polycyclic aromatic hydrocarbons (TPAH), total PCB congeners (TPCB), total pesticides (TPEST), and total technical chlordane (TCHL). Tidal Anacostia ABM found highest TPAH and TCHL upstream at Bladensburg Marina (MD) except for TCHL at site PP near the confluence. Five nontidal MD subtributaries (94% of flow) had 17 sites with bioavailable TPAH, TPCB, or TCHL 2 to 3 times higher than found at the toxic-sediment "hotspots" near Washington. The only TMET noted was Fe at 1 site. TPAH in MD subtributaries was highest near industrial parks and Metro stations. A naphthalene spill was detected in Watts Branch. TPCB (low molecular weight) originated upstream at 1 industrial park. Total technical chlordane (80% of TPEST) was 2 to 5 times the US Food and Drug Administration action in 4 nontidal tributaries where heptachlor indicated legacy chlordane dumpsites. Total technical chlordane fell to reference

  18. Engineering factors influencing Corbicula fouling in nuclear-service water systems

    Energy Technology Data Exchange (ETDEWEB)

    Henager, C.H.; Johnson, K.I.; Page, T.L.

    1983-06-01

    Corbicula fouling is a continuing problem in nuclear-service water systems. More knowledge of biological and engineering factors is needed to develop effective detection and control methods. A data base on Corbicula fouling was compiled from nuclear and non-nuclear power stations and industries using raw water. This data base was used in an analysis to identify systems and components which are conducive to fouling by Corbicula. Bounds on several engineering parameters such as velocity and temperature which support Corbicula growth are given. Service water systems found in BWR and PWR reactors are listed and those that show fouling are identified. Possible safety implications of Corbicula fouling are discussed for specific service water systems. Several effective control methods in current use include backflushing with heated water, centrifugal strainers, and continuous chlorination during spawning seasons.

  19. Can bivalve veligers escape feeding currents of adult bivalves?

    NARCIS (Netherlands)

    Troost, K.; Veldhuizen, R.; Stamhuis, E.J.; Wolff, W.

    2008-01-01

    While the stock of introduced Pacific oysters (Crassostrea gigas) increased in the Oosterschelde estuary (SW Netherlands), so did the filtration pressure of all bivalve species together. In the same period, stocks of native bivalves declined slightly. The expansion of Pacific oysters in Dutch estuar

  20. Recirculation nursery systems for bivalves

    NARCIS (Netherlands)

    Kamermans, P.; Blanco Garcia, A.; Joaquim, Sandra; Matias, Domitilia; Magnesen, Thorolf; Nicolas, J.; Petten, Bruno; Robert, Rene

    2016-01-01

    n order to increase production of bivalves in hatcheries and nurseries, the development of new technology and its integration into commercial bivalve hatcheries is important. Recirculation aquaculture systems (RASs) have several advantages: high densities of the species can be cultured resulting in

  1. Androgenesis: a review through the study of the selfish shellfish Corbicula spp.

    OpenAIRE

    Pigneur, L-M; Hedtke, S M; Etoundi, E; Van Doninck, K.

    2012-01-01

    Among the asexual reproductive modes, androgenesis is probably one of the most astonishing and least studied mechanisms. In this ‘paternal monopolization', the maternal nuclear genome fails to participate in zygote development and offspring are paternal nuclear clones. Obligate androgenesis is known in only a few organisms, including multiple species of clam in the genus Corbicula. Corbicula is a good system to review the evolutionary consequences of this ‘all-male asexuality' because the cyt...

  2. An Analysis of Freshwater Mussels (Unionidae) in the Upper Ohio River Near Huntington, West Virginia: 1992 Studies

    Science.gov (United States)

    1993-12-01

    Taxonomy is consistent with Turgeon et al. (1988). Quantitative mussel samples Quantitative samples that included unionids as well as C. fluminea were...Institute for Water Resources, Water Resources Support Center, Report NWS-83-1, Fort Belvoir, VA. Fuller, S. L. H. (1974). "Clams and mussels ( Mollusca ...Publishers, Ann Arbor, MI, 153-166. McMahon, R. F. (1983). "Ecology of an invasive pest bivalve, Corbicula." The Mollusca (Volume 6): Ecology. W. D

  3. Bivalve carrying capacity in coastal ecosystems

    NARCIS (Netherlands)

    Dame, R.F.; Prins, T.C.

    1998-01-01

    carrying capacity of suspension feeding bivalves in 11 coastal and estuarine ecosystems is examined. Bivalve carrying capacity is defined in terms of water mass residence time, primary production time and bivalve clearance time. Turnover times for the 11 ecosystems are compared both two and three di

  4. Galeommatid bivalves from Phuket, Thailand

    DEFF Research Database (Denmark)

    Lützen, Jørgen; Nielsen, Claus

    2005-01-01

    Twenty-seven species of galeommatid bivalves from six genera have been collected at intertidal reef flats near Phuket Marine Biological Center, Thailand (Andaman Sea, Indian Ocean). Fourteen of the species are new to science and a new genus (Nudiscintilla gen. nov.) has been established. The spec......Twenty-seven species of galeommatid bivalves from six genera have been collected at intertidal reef flats near Phuket Marine Biological Center, Thailand (Andaman Sea, Indian Ocean). Fourteen of the species are new to science and a new genus (Nudiscintilla gen. nov.) has been established...... crustacean, the remainder hide under shale, rocks and coral blocks, often in small intra- or interspecific family flocks. The behaviour was also noted for some of the species. It is presumed that galeommatid species go through a lengthy planktonic phase....

  5. An annotated list of the species of the genus Corbicula from Indonesia (Mollusca: Corbiculidae)

    NARCIS (Netherlands)

    Djajasasmita, Machfudz

    1977-01-01

    The species of the genus Corbicula known from Indonesia are alphabetically listed and noted. Sixteen out of the 35 described species are considered valid, i.e. C. gustaviana, C. moltkiana, C. sumatrana, C. tobae and C. tumida from Sumatra; C. javanica, C. pulchella and C. rivalis from Java; C. bitru

  6. Mercury concentration in bivalve molluscs

    Directory of Open Access Journals (Sweden)

    Szkoda Józef

    2015-09-01

    Full Text Available A total of 85 mussel samples of eight species were examined. Analysis of mercury in the freeze-dried samples was carried out by atomic absorption spectrometry method using direct mercury analyser AMA 254. The analytical procedure for determination of mercury was covered by the quality assurance programme of research and participation in national and international proficiency tests. Concentrations of total mercury in all investigated samples were found to be generally low, in the range of 0.033-0.577 mg/kg of dry weight and of 0.003-0.045 mg/kg of wet weight. The results indicate that obtained levels of mercury in bivalve molluscs are not likely to pose a risk to the health of consumers.

  7. Morphology, Structure of Dimorphic Sperm, and Reproduction in the Hermaphroditic Commensal Bivalve Pseudopythina tsurumaru (Galeommatoidea: Kellidae)

    DEFF Research Database (Denmark)

    Lützen, Jørgen; Jespersen, Åse; Takahashi, Tohru

    2004-01-01

    Galeommatoide, commensal bivalve, reproduction, dimorphic sperm, sperm ultrastructure, spermatozeugma......Galeommatoide, commensal bivalve, reproduction, dimorphic sperm, sperm ultrastructure, spermatozeugma...

  8. Oxidative stress and bivalves: a proteomic approach

    Directory of Open Access Journals (Sweden)

    B McDonagh

    2008-09-01

    Full Text Available Bivalves are of major importance in aquatic ecology, aquaculture, are widely used as sentinel species in environmental toxicology and show remarkable plasticity to molecular oxygen. Excess reactive oxygen species (ROS arising from molecular oxygen can cause oxidative stress and this is also a consequence of exposure to many common environmental pollutants. Indices of oxidative stress have therefore found favor as biomarkers of exposure and effect in environmental toxicology. However, there is a growing body of literature on the use of discovery-led proteomics methods to detect oxidative stress in bivalves. This is because proteins absorb up to 70 % of ROS leading to complication of the proteome. This article explores the background to these developments and assesses the practice and future potential of proteomics in the study of oxidative stress in bivalves.

  9. Microplastics in commercial bivalves from China.

    Science.gov (United States)

    Li, Jiana; Yang, Dongqi; Li, Lan; Jabeen, Khalida; Shi, Huahong

    2015-12-01

    We investigated microplastic pollution in 9 commercial bivalves from a fishery market in China. Multiple types of microplastics, including fibers, fragments and pellets, occurred in the tissue of all bivalves. The number of total microplastics varied from 2.1 to 10.5 items/g and from 4.3 to 57.2 items/individual for bivalves. Scapharca subcrenata contained on average 10.5 items/g and exhibited the highest levels of microplastics by weight. Fibers were the most common microplastics and consisted of more than half of the total microplastics in each of the 8 species. In Alectryonella plicatula, pellets accounted for 60% of the total microplastics. The most common size class was less than 250 μm and accounted for 33-84% of the total microplastics calculated by species. Our results suggest that microplastic pollution was widespread and exhibited a relatively high level in commercial bivalves from China. More intensive investigations on microplastics should be conducted in seafood.

  10. A study of model bivalve siphonal currents

    Science.gov (United States)

    Monismith, Stephen G.; Koseff, Jeffrey R.; Thompson, Janet K.; O'Riordan, Catherine A.; Nepf, Heidi M.

    1990-01-01

    We carried out experiments studying the hydrodynamics of bivalve siphonal currents in a laboratory flume. Rather than use living animals, we devised a simple, model siphon pair connected to a pump. Fluorescence-based flow visualization was used to characterize siphon-jet flows for several geometric configurations and flow speeds. These measurements show that the boundary-layer velocity profile, siphon height, siphon pair orientation, and size of siphon structure all affect the vertical distribution of the excurrent flow downstream of the siphon pair and the fraction of excurrent that is refiltered. The observed flows may effect both the clearance rate of an entire population of siphonate bivalves as well as the efficiency of feeding of any individual. Our results imply that field conditions are properly represented in laboratory flume studies of phytoplankton biomass losses to benthic bivalves when the shear velocity and bottom roughness are matched to values found in the field. Numerical models of feeding by a bivalve population should include an effective sink distribution which is created by the combined incurrent-excurrent flow field. Near-bed flows need to be accounted for to properly represent these benthic-pelagic exchanges. We also present velocity measurements made with a laser-Doppler anemometer (LDA) for a single configuration (siphons flush with bed, inlet downstream) that show that the siphonal currents have a significant local effect on the properties of a turbulent boundary layer.

  11. Fauna Europaea: Mollusca – Bivalvia

    Directory of Open Access Journals (Sweden)

    Rafael Araujo

    2015-07-01

    European freshwater bivalves belong to the Orders Unionoida and Cardiida. All the European unionoids are included in the superfamily Unionoidea, the freshwater mussels or naiads. The European cardiids belong to the following three superfamilies: Cardioidea, Cyrenoidea and Dreissenoidea. Among the Unionoidea there are the most imperilled animal groups on the planet while the Cardioidea includes the cosmopolitan genus Pisidium, the Cyrenoidea the Asiatic clam (Corbicula fluminea and the Dreissenoidea the famous invasive zebra mussel (Dreissena polymorpha. Basic information is summarized on their taxonomy and biology. Tabulations include a complete list of the current estimated families, genera and species.

  12. Bivalve grazing can shape phytoplankton communities

    Science.gov (United States)

    Lucas, Lisa; Cloern, James E.; Thompson, Janet K.; Stacey, Mark T.; Koseff, Jeffrey K.

    2016-01-01

    The ability of bivalve filter feeders to limit phytoplankton biomass in shallow waters is well-documented, but the role of bivalves in shaping phytoplankton communities is not. The coupled effect of bivalve grazing at the sediment-water interface and sinking of phytoplankton cells to that bottom filtration zone could influence the relative biomass of sinking (diatoms) and non-sinking phytoplankton. Simulations with a pseudo-2D numerical model showed that benthic filter feeding can interact with sinking to alter diatom:non-diatom ratios. Cases with the smallest proportion of diatom biomass were those with the fastest sinking speeds and strongest bivalve grazing rates. Hydrodynamics modulated the coupled sinking-grazing influence on phytoplankton communities. For example, in simulations with persistent stratification, the non-sinking forms accumulated in the surface layer away from bottom grazers while the sinking forms dropped out of the surface layer toward bottom grazers. Tidal-scale stratification also influenced vertical gradients of the two groups in opposite ways. The model was applied to Suisun Bay, a low-salinity habitat of the San Francisco Bay system that was transformed by the introduction of the exotic clam Potamocorbula amurensis. Simulation results for this Bay were similar to (but more muted than) those for generic habitats, indicating that P. amurensis grazing could have caused a disproportionate loss of diatoms after its introduction. Our model simulations suggest bivalve grazing affects both phytoplankton biomass and community composition in shallow waters. We view these results as hypotheses to be tested with experiments and more complex modeling approaches.

  13. Oxidative stress and bivalves: a proteomic approach

    OpenAIRE

    2008-01-01

    Bivalves are of major importance in aquatic ecology, aquaculture, are widely used as sentinel species in environmental toxicology and show remarkable plasticity to molecular oxygen. Excess reactive oxygen species (ROS) arising from molecular oxygen can cause oxidative stress and this is also a consequence of exposure to many common environmental pollutants. Indices of oxidative stress have therefore found favor as biomarkers of exposure and effect in environmental toxicology. However, there i...

  14. In-situ bioassays using caged bivalves

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, M.H.; Salazar, S.M.

    1995-12-31

    It is important to make the distinction between chemical measurements to assess bioaccumulation potential versus biological measurements to assess potential bioeffects because bioaccumulation is not a bioeffect. Caging provides a unique opportunity to make synoptic measurements of each and facilitates making these measurements over space and time. Measuring bioaccumulation in resident and transplanted bivalves has probably been the most frequently used form of an in-situ bioassay because bivalves concentrate chemicals in their tissues. They are also easy to collect, cage, and measure. The authors have refined bivalve bioassay methods by minimizing the size range of test animals, making repetitive measurements of the same individuals, and standardizing test protocols for a variety of applications. They are now attempting to standardize criteria for accepting and interpreting data in the same way that laboratory bioassays have been standardized. Growth measurements can serve two purposes in this assessment strategy: (1) An integrated biological response endpoint that is easily quantifiable and with significance to the population, and (2) A means of calibrating bioaccumulation by assessing the relative health and physiological state of tissues that have accumulated the chemicals. In general, the authors have found the highest bioconcentration factors associated with the highest growth rates, the highest concentrations ({micro}g/g) of chemicals in juvenile mussels, and the highest chemical content ({micro}g/animal) in adult mussels. Without accounting for possible dilution of chemical concentrations by tissue growth or magnification through degrowth, contaminant concentrations can be misleading. Examples are provided for the Sudbury River in Massachusetts (Elliptio complanata), San Diego Bay (Mytilus galloprovincialis), and the Harbor Island Superfund Site in Puget Sound (Mytilus trossulus).

  15. Active pelagic migrations of the bivalve Macoma balthica are dangerous

    NARCIS (Netherlands)

    Hiddink, J.G.; Kock, R.P; Wolff, W.J.

    2002-01-01

    The bivalve Macoma balthica migrates twice during the benthic part of its life cycle. During the spring migration (May-June), the newly settled spat (0-group) migrates to the nurseries in the high intertidal. Seven to nine months later, the bivalves migrate back to the low tidal flats and the subtid

  16. Cambrian bivalved arthropod reveals origin of arthrodization.

    Science.gov (United States)

    Legg, David A; Sutton, Mark D; Edgecombe, Gregory D; Caron, Jean-Bernard

    2012-12-07

    Extant arthropods are diverse and ubiquitous, forming a major constituent of most modern ecosystems. Evidence from early Palaeozoic Konservat Lagerstätten indicates that this has been the case since the Cambrian. Despite this, the details of arthropod origins remain obscure, although most hypotheses regard the first arthropods as benthic predators or scavengers such as the fuxianhuiids or megacheirans ('great-appendage' arthropods). Here, we describe a new arthropod from the Tulip Beds locality of the Burgess Shale Formation (Cambrian, series 3, stage 5) that possesses a weakly sclerotized thorax with filamentous appendages, encased in a bivalved carapace, and a strongly sclerotized, elongate abdomen and telson. A cladistic analysis resolved this taxon as the basal-most member of a paraphyletic grade of nekto-benthic forms with bivalved carapaces. This grade occurs at the base of Arthropoda (panarthropods with arthropodized trunk limbs) and suggests that arthrodization (sclerotization and jointing of the exoskeleton) evolved to facilitate swimming. Predatory and fully benthic habits evolved later in the euarthropod stem-lineage and are plesiomorphically retained in pycnogonids (sea spiders) and euchelicerates (horseshoe crabs and arachnids).

  17. Nutritional strategies of the hydrothermal ecosystem bivalves

    Science.gov (United States)

    Le Pennec, Marcel; Donval, Anne; Herry, Angèle

    Studies of deep-sea hydrothermal bivalves have revealed that the species, which are strictly dependent upon the interstitial fluid emissions, derive their food indirectly via symbiotic relationships with chemosynthetic bacteria present in their gill tissues. As the gill plays the main trophic role, structural and ultrastructural modifications occur in the digestive tract. Scanning and transmission electron microscope studies reveal that the digestive system of species belonging to the genera Calyptogena, Bathymodiolus and Bathypecten have anatomical differences. In Calyptogena, the reduction of several parts of the digestive tract and the stomach content which is either empty or full, according to the various species examined indicate that the digestive system is hardly if at all functional. In Bathymodiolus, the labial palps are well developed, the stomach is always full with particles and the two cellular types, digestive and secretory, are present in the digestive gland. All these characteristics indicate that the digestive system is functional. In Bathypecten, the digestive tract is well developed and it seems that it plays the main trophic role. We conclude that the nutritional strategies of the hydrothermal vents bivalves are quite varied. They range from a normal trophic process, through a mixotrophic diet, to one based purely on chemoautotrophic bacteria. The strategy of each species is adapted to and influences its distribution.

  18. Vodní měkkýši Labe mezi Pardubicemi a Hřenskem

    Directory of Open Access Journals (Sweden)

    Luboš Beran

    2005-05-01

    Full Text Available Aquatic molluscs of the Elbe River between Němčice (near Pardubice, Eastern Bohemia, Czech Republic and Hřensko (Northern Bohemia, Czech Republic at 27 localities were investigated from 1994 to 2004. Altogether 40 species (24 gastropods, 16 bivalves from 77 species known on the territory of the Czech Republic were found at sites under study. A gradual invasion of 6 non-native species (Potamopyrgus antipodarum, Physella acuta, Menetus dilatatus, Ferrissia clessiniana, Corbicula fluminea and an extinction of another species (Theodoxus fluviatilis, Planorbis carinatus, Unio crassus, Pisidium amnicum were documented in comparison with historical records. Rare mussel Pseudanodonta complanata and rare pea mussel Pisidium moitessierianum were found at several localities under study and these finds document survival of these bivalves in the Elbe River. Molluscan communities of particular localities were most often usually compounded from species Viviparus viviparus (downstream of loc. 9, Bithynia tentaculata, Radix auricularia, Radix ampla, Unio pictorum, Anodonta anatina, Corbicula fluminea (downstream of loc. 8, Sphaerium rivicola (downstream of loc. 7, Sphaerium corneum s. lat., Pisidium supinum, Dreissena polymorpha.

  19. Lower Jurassic beds with bivalves in south Slovenia

    Directory of Open Access Journals (Sweden)

    Irena Debeljak

    1995-12-01

    Full Text Available The Lower Jurassic beds of south Slovenia outcrop on a surface of several hundred km^ with their thickness in places exceeding 300 meters. They were deposited on the Dinaric Carbonate Platform. In them rich accumulations of characteristic bivalves occur that in Pliensbachian and Toarcian inhabited the wide interconnected shallow water regions of the western and southern margins of Tethysand the eastern Pacific. The most interesting are three large bivalve species:Lithiotis problematica, Cochlearites loppianus and Lithiopedalion scutatus.In addition, numerous other genera can be found: Gervilleiopema, Mytilus, Opisoma and Pachyrisma (with subgenera Pachymegalodon and Durga.The bivalves formed in the region of south Slovenia, in the prevailingly quiet environment of the restricted shelf, sea-bottom mats or biostromes. Their shells can be only rarely found in their growth position. The horizon with bivalves ("lithiotid horizon" in south Slovenia is attributed to Pliensbachian (Domerian. It isup to 75 metres thick and it almost does not pinch out. Within it individual lumachelles of bivalves occur which are from several centimetres to ten metres thick.They are almost exclusively associated with dark, micritic, in places marly limestone and bituminous dolomite. The biodiversity in lumachelles is very low. The intermediate beds that do not contain bivalves mostly consist of oolitic and biospariticlimestone. In this article some localities from various areas of the carbonate platform are described. Considered are paleogeographical and paleoecological conditions that permitted the existence of this typical bivalve fauna.

  20. Microplastics in bivalves cultured for human consumption.

    Science.gov (United States)

    Van Cauwenberghe, Lisbeth; Janssen, Colin R

    2014-10-01

    Microplastics are present throughout the marine environment and ingestion of these plastic particles (microplastics in two species of commercially grown bivalves: Mytilus edulis and Crassostrea gigas. Microplastics were recovered from the soft tissues of both species. At time of human consumption, M. edulis contains on average 0.36 ± 0.07 particles g(-1) (wet weight), while a plastic load of 0.47 ± 0.16 particles g(-1) ww was detected in C. gigas. As a result, the annual dietary exposure for European shellfish consumers can amount to 11,000 microplastics per year. The presence of marine microplastics in seafood could pose a threat to food safety, however, due to the complexity of estimating microplastic toxicity, estimations of the potential risks for human health posed by microplastics in food stuffs is not (yet) possible.

  1. Dynamics of sheet nacre formation in bivalves.

    Science.gov (United States)

    Rousseau, Marthe; Meibom, Anders; Gèze, Marc; Bourrat, Xavier; Angellier, Martine; Lopez, Evelyne

    2009-03-01

    Formation of nacre (mother-of-pearl) is a biomineralization process of fundamental scientific as well as industrial importance. However, the dynamics of the formation process is still not understood. Here, we use scanning electron microscopy and high spatial resolution ion microprobe depth-profiling to image the full three-dimensional distribution of organic materials around individual tablets in the top-most layer of forming nacre in bivalves. Nacre formation proceeds by lateral, symmetric growth of individual tablets mediated by a growth-ring rich in organics, in which aragonite crystallizes from amorphous precursors. The pivotal role in nacre formation played by the growth-ring structure documented in this study adds further complexity to a highly dynamical biomineralization process.

  2. Evidence for variable crystallinity in bivalve shells

    Science.gov (United States)

    Jacob, D. E.; Wehrmeister, U.

    2012-04-01

    Bivalve shells are used as important palaeoclimate proxy archives and monitor regional climate variations. The shells mostly exist of two crystalline polymorphic phases of calcium carbonate calcite (rombohedric) and aragonite (orthorhombic). Calcite is the most stable polymorph at standard conditions, whereas vaterite (hexagonal) is the least stable and only rarely found in these structures. Shells are characterized by organized structures and several micro architectures of mollusc shell structures have been identified: Nacre shows different types: columnar and bricked forms and consists of composite inorganic- organic at the nano-scale. They are well known to display a "brick and mortar" structure. By AFM and FIB/TEM methods it could be shown, that its nanostructure consists of the structures in the range of 50 - 100 nm [1, 2]. These structures are vesicles, consisting of CaCO3 and are individually coated by a membrane. Most probably, the mantle epithelian cells of the bivalve extrude CaCO3 vesicles. By Raman spectroscopic investigations the crystalline CaCO3 polymorphs calcite, aragonite and vaterite, as well as ACC were determined. For some species (Diplodon chilensis patagonicus, Hyriopsis cumingii) pure ACC (i.e. not intermingled with a crystalline phase) could be identified. The presence of an amorphous phase is generally deduced from the lack of definite lattice modes, whereas a broad Raman band in this region is to observe. In most of the cultured pearls (Pinctada maxima and genus Hyriopsis) the ν1-Raman band of ACC clearly displays an asymmetric shape and splits into two different bands according to a nanocrystalline and an amorphous fraction. The FWHMs of most of the crystalline fractions are too high for well crystallized materials and support the assumption of nanocrystalline calcium carbonate polymorph clusters in ACC. They are primarily composed of amorphous calcium carbonate (ACC) which is later transformed into a crystalline modification [3

  3. Bivalve reefs from the Upper Triassic of Iran

    Directory of Open Access Journals (Sweden)

    Franz T. Fürsich

    2005-10-01

    Full Text Available In the Upper Triassic Nayband Formation of east-central Iran, bivalves repeatedly form small patch reefson a mid to outer mixed carbonate-siliciclastic ramp in close stratigraphic neighbourhood to coral and coralspongereefs. In contrast to other Triassic-Jurassic bivalve-dominated patch reefs, the bivalve reefs of theNayband Formation are characterized by a comparatively high diversity of framebuilding taxa. These includetaxa from three different families, i.e., the ostreids Umbostrea emamii, U. iranica and U.? aff. parasiticum, the prospondylids Newaagia stocklini and Persia monstrosa, and the plicatulids Eoplicatula parvadehensis and Pseudoplacunopsis asymmetrica. The bivalve reef constructors may have had a competitive advantage over coral and calcareous sponges in environments characterized by a higher degree of turbidity and/or higher nutrient contents.

  4. Isotopic fingerprints of bacterial chemosymbiosis in the bivalve Loripes lacteus

    Science.gov (United States)

    Dreier, A.; Stannek, L.; Blumenberg, M.; Taviani, M.; Sigovini, M.; Wrede, C.; Thiel, V.; Hoppert, M.

    2012-04-01

    Metazoans with chemosynthetic bacterial endosymbionts are widespread in marine habitats and respective endosymbioses are known from seven recent animal phyla. However, little is known about endosymbioses in fossil settings and, hence, ecological significance in earth history. In the presented project, we investigate the ancient and recent bivalve fauna living at marine sedimentary oxic/anoxic interfaces. Two bivalve species collected from the same benthic environment - a Mediterranean lagoon - were studied in detail. The diet of Loripes lacteus is based on thiotrophic gill symbionts whereas Venerupis aureus is a filter feeding bivalve without symbionts. The presence of three key enzymes from sulfur oxidation (APS-reductase), carbon fixation (RubisCO) and assimilation of nitrogen (glutamine synthetase [GS]) were detected by immunofluorescence in symbionts of Loripes and/or by activity tests in living specimens. In search of biosignatures associated with thiotrophic chemosymbionts that might be suitable for detection of chemosymbiotic diets in recent and fossil bivalve shells, we analyzed the isotopic composition of shell lipids (δ13C) and the bulk organic matrix of the shell (δ13C, δ15N, δ34S). We could show that the combined δ15N and δ13C values from shell extracts are stable in subfossil (Pleistocene) bivalve specimens, as long as the isotopic data is "calibrated" with respective signatures from a filter feeding bivalve sampled from the same site or lithostratigraphic bed.

  5. Co-option of bacteriophage lysozyme genes by bivalve genomes

    Science.gov (United States)

    Wang, Chunyang; Jin, Min; Lan, Jiangfeng; Ye, Ting; Hui, Kaimin; Tan, Jingmin; Wang, Zheng; Wang, Wen; Han, Guan-Zhu

    2017-01-01

    Eukaryotes have occasionally acquired genetic material through horizontal gene transfer (HGT). However, little is known about the evolutionary and functional significance of such acquisitions. Lysozymes are ubiquitous enzymes that degrade bacterial cell walls. Here, we provide evidence that two subclasses of bivalves (Heterodonta and Palaeoheterodonta) acquired a lysozyme gene via HGT, building on earlier findings. Phylogenetic analyses place the bivalve lysozyme genes within the clade of bacteriophage lysozyme genes, indicating that the bivalves acquired the phage-type lysozyme genes from bacteriophages, either directly or through intermediate hosts. These bivalve lysozyme genes underwent dramatic structural changes after their co-option, including intron gain and fusion with other genes. Moreover, evidence suggests that recurrent gene duplication occurred in the bivalve lysozyme genes. Finally, we show the co-opted lysozymes exhibit a capacity for antibacterial action, potentially augmenting the immune function of related bivalves. This represents an intriguing evolutionary strategy in the eukaryote–microbe arms race, in which the genetic materials of bacteriophages are co-opted by eukaryotes, and then used by eukaryotes to combat bacteria, using a shared weapon against a common enemy. PMID:28100665

  6. Doplněk k poznání vodních měkkýšů Labe mezi Hřenskem a Střekovem a srovnání s malakofaunou Labe v jiných úsecích

    Directory of Open Access Journals (Sweden)

    Luboš Beran

    2009-11-01

    Full Text Available This paper completes knowledge on aquatic molluscs of the free flowing part of the Elbe River between Hřensko and the weir with lock in Ústí nad Labem – Střekov. Altogether, 21 species of aquatic molluscs (9 gastropods, 12 bivalves were found in 2009. Viviparus viviparus, Potamopyrgus antipodarum, Bithynia tentaculata, Ancylus fluviatilis, Unio pictorum, Anodonta anatina, Corbicula fluminea, Sphaerium corneum and Pisidium supinum were the most frequently occurring molluscs found during this research. The occurrence of two endangered bivalves Pseudanodonta complanata and Pisidium moitessierianum was recorded. No significant difference from the previous author’s research was found. Molluscan communities of this part of the river were compared with those of the upper canalized part of the Elbe River which contain more species (especially gastropods living predominantly in stagnant or slowly flowing waters e. g. Stagnicola palustris, S. corvus, Lymnaea stagnalis, Planorbis planorbis, Bathyomphalus contortus, Anisus vortex, Hippeutis complanatus, Ferrissia fragilis.

  7. Modeling the carbon isotope composition of bivalve shells (Invited)

    Science.gov (United States)

    Romanek, C.

    2010-12-01

    The stable carbon isotope composition of bivalve shells is a valuable archive of paleobiological and paleoenvironmental information. Previous work has shown that the carbon isotope composition of the shell is related to the carbon isotope composition of dissolved inorganic carbon (DIC) in the ambient water in which a bivalve lives, as well as metabolic carbon derived from bivalve respiration. The contribution of metabolic carbon varies among organisms, but it is generally thought to be relatively low (e.g., organism and high (>90%) in the shells from terrestrial organisms. Because metabolic carbon contains significantly more C-12 than DIC, negative excursions from the expected environmental (DIC) signal are interpreted to reflect an increased contribution of metabolic carbon in the shell. This observation contrasts sharply with modeled carbon isotope compositions for shell layers deposited from the inner extrapallial fluid (EPF). Previous studies have shown that growth lines within the inner shell layer of bivalves are produced during periods of anaerobiosis when acidic metabolic byproducts (e.g., succinic acid) are neutralized (or buffered) by shell dissolution. This requires the pH of EPF to decrease below ambient levels (~7.5) until a state of undersaturation is achieved that promotes shell dissolution. This condition may occur when aquatic bivalves are subjected to external stressors originating from ecological (predation) or environmental (exposure to atm; low dissolved oxygen; contaminant release) pressures; normal physiological processes will restore the pH of EPF when the pressure is removed. As a consequence of this process, a temporal window should also exist in EPF at relatively low pH where shell carbonate is deposited at a reduced saturation state and precipitation rate. For example, EPF chemistry should remain slightly supersaturated with respect to aragonite given a drop of one pH unit (6.5), but under closed conditions, equilibrium carbon isotope

  8. Additions to the Marine bivalve mollusks of Peru

    Directory of Open Access Journals (Sweden)

    Carlos Paredes

    2013-06-01

    Full Text Available The following species of marine bivalve mollusks were recorded for the first time from the Peruvian sea: Glycymeris (Axinactus delessertii (Reeve, 1843; Botula cylista Berry, 1959; Parahyotissa (Pliohyotissa quercinus (Sowerby II, 1871; Pitar (Pitar helenae Olsson, 1961; Eurhomalea lenticularis (Sowerby I, 1835; and Cardiomya planetica (Dall, 1908. Description, habitat and the geographical distribution are cited for each species.

  9. The adaptive value of migrations for the bivalve Macoma balthica

    NARCIS (Netherlands)

    Hiddink, Johan Gerrit

    2002-01-01

    This thesis is about the movements of the coastal marine bivalve Macoma balthica. M. balthica migrates over several kilometres between nurseries at high tidal flats, where juveniles are found in high numbers, and the adult habitat on low-lying tidal flats. Most benthic species in the Wadden Sea have

  10. Molecular approaches to bivalve population studies: a review

    Directory of Open Access Journals (Sweden)

    Dragomir-Cosmin David

    2011-12-01

    Full Text Available This paper presents a literature review concerning the importance of molecular approaches in bivalve’s population study. The class Bivalvia counts more than 20,000 species with a wide distribution both in freshwater and marine environment. Given their importance especially in aquaculture as a source of food, they have also a strong economic impact upon human society. This review encompasses best practices in bivalve studies from field sampling to laboratory analyses, addressing questions about molecular methods and tools commonly used by specialized researchers. Molecular tools specifically deals with phylogeography, population genetics, biology, ecology and taxonomy. In all these fields, molecular markers play an important role by completing some unanswered questions such as the role of the bivalves in the ecosystems in relation to anthropogenic and global change issues. Numerous genetic markers were developed for specific problems, thereferore we identify as a major issue the absence of uniform and universally recognized methods. The various sections of the paper emphasize from peer reviewed literature literature which are considered the most useful markers, costs and benefits of different methodology, major gaps of knowledge.in bivalve population studies. By reviewing virtually all genetic markers employed during nearly half a century of bivalve molecular research, in our opinion two are the best option “tools: the mitochondrial COI (cytochrome oxidase subunit I and nuclear ITS2 (internal transcribed spacer 2.

  11. The Holocene and Recent marine Bivalve Mollusca of Surinam

    NARCIS (Netherlands)

    Regteren Altena, van C.O.

    1968-01-01

    As the preparation of an annotated check list of the marine Mollusca of Surinam (Dutch Guiana) will take some more years, it was thought appropriate to publish a preliminary report on the bivalves. This report consists of a list of 126 species with a few notes containing, i.a., the description of se

  12. Lower Carboniferous marine bivalves from the Cantabrian Mountains (Spain)

    NARCIS (Netherlands)

    Amler, M.R.W.; Winkler Prins, C.F.

    1999-01-01

    The Lower Carboniferous bivalves of the Vegamián and Genicera formations are described, followed by a brief discussion on palaeoenvironmental and palaeogeographical aspects. The black shales of the Vegamián Fm. (Tournaisian) yield a peculiar association of euchondriid taxa (Euchondria wagneri sp. no

  13. Artificially evolved functional shell morphology of burrowing bivalves

    DEFF Research Database (Denmark)

    Germann, D. P.; Schatz, W.; Hotz, Peter Eggenberger

    2014-01-01

    dimensional (3D) objects, the first ever artificial evolution of a physical bivalve shell was performed. The result was a vertically flattened shell occupying only the top sediment layers. Insufficient control of the sediment was the major limitation of the setup and restricted the significance of the results...

  14. The influence of fish cage culture on δ13C and δ15N of filter-feeding Bivalvia (Mollusca).

    Science.gov (United States)

    Benedito, E; Figueroa, L; Takeda, A M; Manetta, G I

    2013-11-01

    The objective of this study was to evaluate the effect of Oreochromis niloticus cage culture promoted variations in the δ13C and δ15N in Corbicula fluminea (Mollusca; Bivalvia) and in the sediment of an aquatic food web. Samples were taken before and after net cage installation in the Rosana Reservoir (Paranapanema River, PR-SP). Samples of specimens of the bivalve filterer C. fluminea and samples of sediment were collected using a modified Petersen grab. All samples were dried in an oven (60 °C) for 72 hours, macerated to obtain homogenous fine powders and sent for carbon (δ13C) and nitrogen (δ15N) isotopic value analysis in a mass spectrometer. There were significant differences in the δ13C and δ15N values of the invertebrate C. fluminea between the beginning and the end of the experiment. There were no differences between the δ13C and δ15N values of sediment. These results indicate that the installation of fish cage culture promoted impacts in the isotopic composition of the aquatic food web organisms, which could exert influence over the native species and the ecosystem.

  15. The influence of fish cage culture on δ{sup 13}C and δ{sup 15}N of filter-feeding Bivalvia (Mollusca)

    Energy Technology Data Exchange (ETDEWEB)

    Benedito, E.; Takeda, A.M., E-mail: eva@nupelia.uem.br [Universidade Estadual de Maringa (UEM), PR (Brazil). Nucleo de Pesquisas em Limnologia, Ictiologia e Aquicultura; Figueroa, L. [Universidade Estadual de Maringa (UEM), PR (Brazil). Pos-Graduacao em Ecologia de Ambientes Aquaticos Continentais; Manetta, GI. [Universidade Estadual de Maringa (UEM), PR (Brazil). Pos-Graduacao em Biologia Comparada

    2013-11-15

    The objective of this study was to evaluate the effect of Oreochromis niloticus cage culture promoted variations in the δ{sup 13}C and δ{sup 15}N in Corbicula fluminea (Mollusca; Bivalvia) and in the sediment of an aquatic food web. Samples were taken before and after net cage installation in the Rosana Reservoir (Paranapanema River, PR-SP). Samples of specimens of the bivalve filter C. fluminea and samples of sediment were collected using a modified Petersen grab. All samples were dried in an oven (60 °C) for 72 hours, macerated to obtain homogenous fine powders and sent for carbon (δ{sup 13}C) and nitrogen (δ{sup 15}N) isotopic value analysis in a mass spectrometer. There were significant differences in the δ{sup 13}C and δ{sup 15}N values of the invertebrate C. fluminea between the beginning and the end of the experiment. There were no differences between the δ{sup 13}C and δ{sup 15}N values of sediment. These results indicate that the installation of fish cage culture promoted impacts in the isotopic composition of the aquatic food web organisms, which could exert influence over the native species and the ecosystem. (author)

  16. Protective role of edible clam Paphia malabarica (Chemnitz) against lipid peroxidation and free radicals

    Digital Repository Service at National Institute of Oceanography (India)

    Pawar, R.T.; Nagvenkar, S.S.; Jagtap, T.G.

    Kumar MNV. Role of antioxidants in prophylaxis and therapy: A phar- maceutical prospective. J. Control. Release 2006; 113:189-207. [42] Conners DE. Biomarkers of oxidative stress in freshwater clams (Corbicula fluminea) as mechanistic tools to evaluate...

  17. Geographic distribution of mercury in asiatic clams, Corbicuia plumihea, from the North Fork Holston River, Virginia

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A study was conducted quantifying mercury concentrations in the Asiatic clam, Corbicula fluminea, from the North Fork Holston River, Virginia. The purpose of this...

  18. DNA damage in gill cells of Corbicula japonica exposed to natural and anthropogenic stressors

    Directory of Open Access Journals (Sweden)

    Valentina Vladimirovna Slobodskova

    2015-06-01

    The results are presented as the percentage distribution of nuclei in the various damage classes and summarized in an index of DNA integrity or genetic damage index GDI (Cavas, Kohen, 2008: The results from our study showed significant level of DNA damage from the C. japonica which were collected from polluted sites. Unpolluted sites were described as with no or minimal DNA strand breaks. Mollusks collected at polluted areas (estuary Razdolnaya river, lagoon Tihaya showed high levels of DNA damage, GDI is equal to 3.22±0.2 and 3.11±0.7 in gills respectively. C. japonica obtained from a ‘clean’ areas (estuary Artemovka river, estuary Partizanskaya river demonstrate less high level of DNA damage destruction, GDI is equal to 0,6±0,08 and 0,71±0,12 in gills respectively. Lipid peroxidation level was assayed measurement of malondialdehyde (MDA, a decomposition product of polyunsaturated fatty acids hydro peroxides were determined by the TBA reaction. The absorbance was read at 532 nm after removal of substances (TBARS formed was calculated by using an extinction coefficient of 1.56*105 M-1 cm -1 formed per g dry weight. C. japonica sampled at Artemovka estuary, Partizanskaya estuary, Razdolnaya estuary, Tihaya lagoon showed LPX level (3.46±0.59, 5.62±0.82, 12.85±0.52, 15.32±1.13 nmol TBARS/g dry wt in gills respectively. In conclusion, it can be noted that in the course of the experiment we found a clear relationship between the amount of DNA damage and the level of peroxidation products (MDA in the gills of bivalve C. japonica, collected from sites with varying degrees of anthropogenic load. It should be emphasized that the shellfish that live in polluted areas are likely to be in a state of oxidative stress, which is one of the causes the degradation of DNA.

  19. The Bivalve Yangtzedonta is not the Brachiopod Xianfengella

    Institute of Scientific and Technical Information of China (English)

    YU Wen

    2005-01-01

    The alleged "holotype" of the bivalve Yangtzedontaprimitiva Yu, 1985 figured by Qian (2001) is a broken and distorted specimen of the brachiopod Xianfengella prima He and Yang, 1982 and not the holotype of Y. primitiva. Qian contends that the oldest recognized monoplacophoran, Maikhanella pristinis (Jiang, 1980), is neither a monoplacophoran nor the oldest molluscan fossil in the Meishucunian Stage of China. Furthermore, he considers that the oldest bivalve Xianfengoconcha elliptica Zhang, 1980 is an inarticulate brachiopod, not a mollusc. Watsonella yunnanensis (He and Yang, 1982), is associated with Yangtzedonta primitiva Yu but indicates no evolutionary relationship between the Classes Rostroconchia and Bivalvia in the Lower Cambrian Zhongyicun Member of the Yuhucun Formation. Qian's confusion in using non-molluscan fossils to discuss the early evolution of shelled molluscs also confuses the basic concepts of the respective groups.

  20. Bivalves: Indicateurs de pollution microbienne des eaux littorales

    OpenAIRE

    Plusquellec, A; Beucher, M; Legal, Y

    1984-01-01

    Une étude a été réalisée en baie de Concarneau (France), dans le but de comparer la contamination de l'eau et de moules d'un même site naturel par le dénombrement des indicateurs fécaux usuels : Coliformes fécaux et Streptocoques fécaux. La concentration par les bivalves est importante, mais diffère pour les deux indicateurs bactériens. Le dénombrement des Streptocoques fécaux dans les bivalves permet d'annuler une partie des variations observées dans l'eau. L'efficacité des moules comme maté...

  1. Dynamic changes in the accumulation of metabolites in brackish water clam Corbicula japonica associated with alternation of salinity.

    Science.gov (United States)

    Koyama, Hiroki; Okamoto, Seiji; Watanabe, Naoki; Hoshino, Naoshige; Jimbo, Mitsuru; Yasumoto, Ko; Watabe, Shugo

    2015-03-01

    The brackish water clam Corbicula japonica inhabits rivers and brackish waters throughout Japan where the major fishing grounds in the Ibaraki Prefecture, Japan, are located at the Hinuma Lake and Hinuma River. Water salinity in the Lake Hinuma is low and stable due to the long distance from the Pacific Ocean, whereas that in the downstream of the river varies daily due to a strong effect of tidal waters. In the present study, we dissected the gill and foot muscle of brackish water clam collected from these areas, and subjected them to metabolome analysis by capillary electrophoresis-time-of-flight mass spectrometry. More than 200 metabolites including free amino acids, peptides and organic acids were identified, and their amounts from the foot muscle tend to be higher than those from the gill. The principal component analysis revealed that the amount of each metabolite was different among sampling areas and between the gill and foot muscle, whereas no apparent differences were observed between male and female specimens. When the metabolites in the female clam at high salinity were compared with those at low salinity, concentrations of β-alanine, choline, γ-aminobutyric acid, ornithine and glycine betaine were found to be changed in association with salinity. We also compared various metabolites in relation to metabolic pathways, suggesting that many enzymes were involved in their changes depending on salinity.

  2. Indian marine bivalves: Potential source of antiviral drugs

    Digital Repository Service at National Institute of Oceanography (India)

    Chatterji, A.; Ansari, Z.A.; Ingole, B.S.; Bichurina, M.A.; Sovetova, M.; Boikov, Y.A.

    in large quantities by traditional methods and sold live in the market for human consumption. The economically important sp e cies of marine bivalves are green mussel ( Perna viridis ), e s tuarine oyster ( Crassostrea madrasensis ), giant oyster... in developing an effecti ve drug has been the unique characteristics of antigenic variation of virus resulting in the emergence of new variant virus strains 14 . There are a number of antiviral drugs introduced in the market such as tricyclic sy m- metric...

  3. Ocean Acidification Has Multiple Modes of Action on Bivalve Larvae.

    Science.gov (United States)

    Waldbusser, George G; Hales, Burke; Langdon, Chris J; Haley, Brian A; Schrader, Paul; Brunner, Elizabeth L; Gray, Matthew W; Miller, Cale A; Gimenez, Iria; Hutchinson, Greg

    2015-01-01

    Ocean acidification (OA) is altering the chemistry of the world's oceans at rates unparalleled in the past roughly 1 million years. Understanding the impacts of this rapid change in baseline carbonate chemistry on marine organisms needs a precise, mechanistic understanding of physiological responses to carbonate chemistry. Recent experimental work has shown shell development and growth in some bivalve larvae, have direct sensitivities to calcium carbonate saturation state that is not modulated through organismal acid-base chemistry. To understand different modes of action of OA on bivalve larvae, we experimentally tested how pH, PCO2, and saturation state independently affect shell growth and development, respiration rate, and initiation of feeding in Mytilus californianus embryos and larvae. We found, as documented in other bivalve larvae, that shell development and growth were affected by aragonite saturation state, and not by pH or PCO2. Respiration rate was elevated under very low pH (~7.4) with no change between pH of ~ 8.3 to ~7.8. Initiation of feeding appeared to be most sensitive to PCO2, and possibly minor response to pH under elevated PCO2. Although different components of physiology responded to different carbonate system variables, the inability to normally develop a shell due to lower saturation state precludes pH or PCO2 effects later in the life history. However, saturation state effects during early shell development will carry-over to later stages, where pH or PCO2 effects can compound OA effects on bivalve larvae. Our findings suggest OA may be a multi-stressor unto itself. Shell development and growth of the native mussel, M. californianus, was indistinguishable from the Mediterranean mussel, Mytilus galloprovincialis, collected from the southern U.S. Pacific coast, an area not subjected to seasonal upwelling. The concordance in responses suggests a fundamental OA bottleneck during development of the first shell material affected only by

  4. Ocean Acidification Has Multiple Modes of Action on Bivalve Larvae.

    Directory of Open Access Journals (Sweden)

    George G Waldbusser

    Full Text Available Ocean acidification (OA is altering the chemistry of the world's oceans at rates unparalleled in the past roughly 1 million years. Understanding the impacts of this rapid change in baseline carbonate chemistry on marine organisms needs a precise, mechanistic understanding of physiological responses to carbonate chemistry. Recent experimental work has shown shell development and growth in some bivalve larvae, have direct sensitivities to calcium carbonate saturation state that is not modulated through organismal acid-base chemistry. To understand different modes of action of OA on bivalve larvae, we experimentally tested how pH, PCO2, and saturation state independently affect shell growth and development, respiration rate, and initiation of feeding in Mytilus californianus embryos and larvae. We found, as documented in other bivalve larvae, that shell development and growth were affected by aragonite saturation state, and not by pH or PCO2. Respiration rate was elevated under very low pH (~7.4 with no change between pH of ~ 8.3 to ~7.8. Initiation of feeding appeared to be most sensitive to PCO2, and possibly minor response to pH under elevated PCO2. Although different components of physiology responded to different carbonate system variables, the inability to normally develop a shell due to lower saturation state precludes pH or PCO2 effects later in the life history. However, saturation state effects during early shell development will carry-over to later stages, where pH or PCO2 effects can compound OA effects on bivalve larvae. Our findings suggest OA may be a multi-stressor unto itself. Shell development and growth of the native mussel, M. californianus, was indistinguishable from the Mediterranean mussel, Mytilus galloprovincialis, collected from the southern U.S. Pacific coast, an area not subjected to seasonal upwelling. The concordance in responses suggests a fundamental OA bottleneck during development of the first shell material

  5. Absence of aryl hydrocarbon hydroxylase (AHH) in three marine bivalves

    Energy Technology Data Exchange (ETDEWEB)

    Vandermeulen, J.H. (Bedford Inst. of Oceanography, Dartmouth, Nova Scotia); Penrose, W.R.

    1978-05-01

    Bivalves exposed to short-term (4 d) and long-term (6 yr) oil pollution were assayed for aryl hydrocarbon hydroxylase (AHH) and N-demethylase activity. Short-term induction studies were carried out on Mya arenaria, Mytilus edulis, and Ostrea edulis incubated in aqueous extracts of Kuwait crude oil or Bunker C (fuel) oil. For the chronic-induction studies Mya arenaria and Mytilus edulis were collected from oiled clam beds (Arrow Bunker C) in Chedabucto Bay, Nova Scotia. None of the bivalves showed any basal or petroleum-hydrocarbon-induced aryl hydrocarbon hydroxylase or N-demethylase activity, as shown by their inability to metabolize benzopyrene or imipramine. In contrast, oil-free control trout and trout taken from a polluted lake readily metabolized both these compounds. The inability of these bivalves to degrade petroleum aromatic hydrocarbons and the tendency of these compounds to accumulate in their tissues present an opportunity for transfer of unaltered hydrocarbons into the food chain.

  6. Effects of millimeter wave carbon fibers on filter-feeding freshwater invertebrates.

    Science.gov (United States)

    Soucek, David J; Dickinson, Amy; Cropek, Donald M

    2010-05-01

    The purpose of our study was to investigate the sub-lethal effects of millimeter wave carbon fibers (MWCF), a military obscurant, on filter-feeding freshwater invertebrates. We observed decreased survival, reproduction, and oxygen consumption in Daphnia magna at realistic loading rates. In experiments with the Asiatic clam (Corbicula fluminea), soft tissue dry weight and tissue condition index were not significantly different among control and MWCF exposed treatments; however, using a (15)N labeled alga as food, we observed decreased nitrogen turnover in tissues of clams exposed to MWCF, suggesting lower filtering or ingestion rates. Our findings combined with previous demonstrations of MWCF toxicity to green algae suggest that over a period of several months, bivalve growth may be inhibited, and cladoceran populations may be even more strongly affected by MWCF. Given that these fibers are persistent, further experiments should be conducted to determine the longer-term effects of contamination of water bodies with MWCF.

  7. Effect of dietary polyunsaturated fatty acids on reproductive output and larval growth of bivalves

    NARCIS (Netherlands)

    Hendriks, I.E.; Van Duren, L.A.; Herman, P.M.J.

    2003-01-01

    The pre-spawning condition of adult bivalves is influenced by quantity and quality of available food. For bivalves, the essential polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid (EPA) 20:5(n-3) and docosahexaenoic acid (DHA) 22:6(n-3) are presumed to determine the nutritional value of alga

  8. Lower Oligocene bivalves of Ramanian Stage from Kachchh, Gujarat, India

    Indian Academy of Sciences (India)

    R P Kachhara; R L Jodhawat; K Bigyapati Devi

    2012-04-01

    Marine Oligocene sequences in India outcrop only in western part of Kachchh. Earlier researchers have recognized the Oligocene strata under the Nari Series (Nagappa 1959; Chatterji and Mathur 1966). The Nari Series has a type area in Pakistan. It has two subdivisions – the Lower Nari (Lower Oligocene) and the Upper Nari (Upper Oligocene). It seems that there is no valid proof about the age of the Lower Nari due to lack of proper fauna (Eames 1975), and according to Pascoe (1962), the Upper Nari slightly transgress into Aquitanian (Lower Miocene), therefore, one has to be very cautious. Biswas and Raju (1971) reclassified the Oligocene strata of Kachchh and lithostratigraphically clubbed them as the Maniyara Fort Formation with type section along the Bermoti stream. This Formation has four members. The lower three members correspond to the Ramanian Stage (Lower Oligocene, Biswas 1971, 1973) while the uppermost to the Waiorian Stage (Upper Oligocene, Biswas 1965, 1971, 1973). The Ramanian Stage is characterized by large forams especially Nummulites fichteli, Nummulites fichteli intermedius, Lepidocyclina (Eulepidina) dialata and Operculina sp. Several ostracods are also known to occur. Megafauna include bivalves, gastropods, echinoids, corals, mammals and reptiles. Concerning bivalves earlier researchers have recorded a few taxa namely Trisidos semitorta (Lamarck), Cubitostrea angulata (J de C Sowerby), Pecten (Amussiopecten) labadyei d’Archiac and Haime, Periglypta puerpera (Linne’) var. aglaurae Brongniart, Ostrea fraasi Mayer Eymer and listed Pecten laevicostatus J de C Sowerby, Callista pseudoumbonella Vredenburg and Clementia papyracea (Gray) from Kachchh as against overall 42 forms from the Nari Series as a whole (Vredenburg 1928). This tempted us to make an attempt to collect bivalve fauna systematically which are occurring prolifically in the Ramanian Stage. In the present work, for this purpose, sections are worked out around Lakhpat (23° 50′N; 68

  9. Lower Oligocene bivalves of Ramanian Stage from Kachchh, Gujarat, India

    Science.gov (United States)

    Kachhara, R. P.; Jodhawat, R. L.; Devi, K. Bigyapati

    2012-04-01

    Marine Oligocene sequences in India outcrop only in western part of Kachchh. Earlier researchers have recognized the Oligocene strata under the Nari Series (Nagappa 1959; Chatterji and Mathur 1966). The Nari Series has a type area in Pakistan. It has two subdivisions - the Lower Nari (Lower Oligocene) and the Upper Nari (Upper Oligocene). It seems that there is no valid proof about the age of the Lower Nari due to lack of proper fauna (Eames 1975), and according to Pascoe (1962), the Upper Nari slightly transgress into Aquitanian (Lower Miocene), therefore, one has to be very cautious. Biswas and Raju (1971) reclassified the Oligocene strata of Kachchh and lithostratigraphically clubbed them as the Maniyara Fort Formation with type section along the Bermoti stream. This Formation has four members. The lower three members correspond to the Ramanian Stage (Lower Oligocene, Biswas 1971, 1973) while the uppermost to the Waiorian Stage (Upper Oligocene, Biswas 1965, 1971, 1973). The Ramanian Stage is characterized by large forams especially Nummulites fichteli, Nummulites fichteli intermedius, Lepidocyclina ( Eulepidina) dialata and Operculina sp. Several ostracods are also known to occur. Megafauna include bivalves, gastropods, echinoids, corals, mammals and reptiles. Concerning bivalves earlier researchers have recorded a few taxa namely Trisidos semitorta (Lamarck), Cubitostrea angulata (J de C Sowerby), Pecten ( Amussiopecten) labadyei d'Archiac and Haime, Periglypta puerpera (Linne') var. aglaurae Brongniart, Ostrea fraasi Mayer Eymer and listed Pecten laevicostatus J de C Sowerby, Callista pseudoumbonella Vredenburg and Clementia papyracea (Gray) from Kachchh as against overall 42 forms from the Nari Series as a whole (Vredenburg 1928). This tempted us to make an attempt to collect bivalve fauna systematically which are occurring prolifically in the Ramanian Stage. In the present work, for this purpose, sections are worked out around Lakhpat (23°50'N; 68°47'E

  10. Toxic dinoflagellates and Vibrio spp. act independently in bivalve larvae.

    Science.gov (United States)

    De Rijcke, M; Van Acker, E; Nevejan, N; De Schamphelaere, K A C; Janssen, C R

    2016-10-01

    Harmful algal blooms (HABs) and marine pathogens - like Vibrio spp. - are increasingly common due to climate change. These stressors affect the growth, viability and development of bivalve larvae. Little is known, however, about the potential for interactions between these two concurrent stressors. While some mixed exposures have been performed with adult bivalves, no such work has been done with larvae which are generally more sensitive. This study examines whether dinoflagellates and bacteria may interactively affect the viability and immunological resilience of blue mussel Mytilus edulis larvae. Embryos were exposed to environmentally relevant concentrations (100, 500, 2500 & 12,500 cells ml(-1)) of a dinoflagellate (Alexandrium minutum, Alexandrium ostenfeldii, Karenia mikimotoi, Protoceratium reticulatum, Prorocentrum cordatum, P. lima or P. micans), a known pathogen (Vibrio coralliilyticus/neptunius-like isolate or Vibrio splendidus; 10(5) CFU ml(-1)), or both. After five days of exposure, significant (p larval viability and larval development were found for all dinoflagellates (except P. cordatum) and V. splendidus. Yet, despite the individual effect of each stressor, no significant interactions were found between the pathogens and harmful algae. The larval viability and the phenoloxidase innate immune system responded independently to each stressor. This independence may be related to a differential timing of the effects of HABs and pathogens.

  11. Protozoan parasites of bivalve molluscs: literature follows culture.

    Science.gov (United States)

    Fernández Robledo, José A; Vasta, Gerardo R; Record, Nicholas R

    2014-01-01

    Bivalve molluscs are key components of the estuarine environments as contributors to the trophic chain, and as filter -feeders, for maintaining ecosystem integrity. Further, clams, oysters, and scallops are commercially exploited around the world both as traditional local shellfisheries, and as intensive or semi-intensive farming systems. During the past decades, populations of those species deemed of environmental or commercial interest have been subject to close monitoring given the realization that these can suffer significant decline, sometimes irreversible, due to overharvesting, environmental pollution, or disease. Protozoans of the genera Perkinsus, Haplosporidium, Marteilia, and Bonamia are currently recognized as major threats for natural and farmed bivalve populations. Since their identification, however, the variable publication rates of research studies addressing these parasitic diseases do not always appear to reflect their highly significant environmental and economic impact. Here we analyzed the peer- reviewed literature since the initial description of these parasites with the goal of identifying potential milestone discoveries or achievements that may have driven the intensity of the research in subsequent years, and significantly increased publication rates. Our analysis revealed that after initial description of the parasite as the etiological agent of a given disease, there is a time lag before a maximal number of yearly publications are reached. This has already taken place for most of them and has been followed by a decrease in publication rates over the last decade (20- to 30- year lifetime in the literature). Autocorrelation analyses, however, suggested that advances in parasite purification and culture methodologies positively drive publication rates, most likely because they usually lead to novel molecular tools and resources, promoting mechanistic studies. Understanding these trends should help researchers in prioritizing research

  12. Effect of different extraction procedures on antimicrobial activity of marine bivalves: A comparison

    Digital Repository Service at National Institute of Oceanography (India)

    Sharma, S.; Chatterji, A.; Das, P.

    Anti-bacterial activity was evaluated in different crude extracts of five commercially important edible marine bivalves, namely Meretrix casta (Chemnitz), Polymesoda (Geloina) P. erosa (Solander), Perna viridis (Linnaeus), Crassostrea gryphoides...

  13. [Energy metabolism and body mass ratio in bivalves mollusca (Mollusca: Bivalvia)].

    Science.gov (United States)

    Vladimirova, I G; Kleĭmenov, S Iu; Radzinskaia, L I

    2003-01-01

    On the basis of experimental and published data, the interspecific and intraspecific (ontogenetic) dependence of energy metabolism on body weight in bivalves was calculated. Changes in the parameters of intraspecific allometric dependence under the effect of environmental factors were analyzed. The rate of comparable standard metabolism (coefficient a at k = 0.76) was shown to vary in different taxonomic and zoogeographic groups of bivalves.

  14. Influence of intertidal recreational fisheries and 'bouchot' mussel culture on bivalve recruitment.

    Science.gov (United States)

    Toupoint, Nicolas; Barbier, Pierrick; Tremblay, Réjean; Archambault, Philippe; McKindsey, Christopher W; Winkler, Gesche; Meziane, Tarik; Olivier, Frédéric

    2016-06-01

    In coastal environments, fishing and aquaculture may be important sources of disturbance to ecosystem functioning, the quantification of which must be assessed to make them more sustainable. In the Chausey Archipelago, France, recreational fishing and commercial shellfish farming are the only two evident anthropogenic activities, dominated by bivalve hand-raking and 'bouchot' mussel culture, respectively. This study evaluates the impact of both activities on bivalve recruitment dynamics by comparing primary recruitment intensity (short-term effect) and recruitment efficiency (medium-term effect) by sampling bivalves in reference (undisturbed) and disturbed (i.e. subjected to hand-raking or in 'bouchot' mussel culture areas) parcels throughout and at the end of the recruitment season, respectively. Specific hypotheses evaluated were that (H1) bivalve hand-raking negatively affects bivalve recruitment and that (H2) 'bouchot' mussel culture promotes bivalve recruitment. Patterns in bivalve community structure in reference parcels (i.e. natural pattern) differed between initial and final recruitment, underlining the great importance of early post-settlement processes, particularly secondary dispersal. Primary recruitment intensity was inhibited in hand-raking parcels whereas it was promoted in 'bouchot' mussel culture parcels, but the effect on recruitment efficiency was muted for both activities due to post-settlement processes. Nevertheless, the importance of effects that occur during the first step of recruitment should not be ignored as they may affect bivalve communities and induce immediate consequences on the trophic web through a cascade effect. Finally, it is highlighted that hand-raking damages all life stages of the common cockle Cerastoderma edule, one of the major target species, suggesting that this activity should be managed with greater caution than is currently done.

  15. Nursery function of coastal temperate benthic habitats: New insight from the bivalve recruitment perspective

    Science.gov (United States)

    Barbier, Pierrick; Meziane, Tarik; Forêt, Martin; Tremblay, Réjean; Robert, René; Olivier, Frédéric

    2017-03-01

    Marine habitat function has been typically investigated in terms of biogeochemical regulation but rarely in terms of population renewal, which is mainly controlled by recruitment dynamics. The recruitment phase is crucial for organisms with a bentho-pelagic life cycle, such as bivalves, and it regulates the population renewal success. This study provides new insight on the role of temperate benthic habitats on bivalve recruitment, as a function of nursery areas. Six dominant benthic habitats of the Chausey archipelago (Normandy, France) were studied. In each habitat, bivalve recruit assemblages were described at the end of two reproductive seasons. Furthermore, Ostrea edulis juveniles were immerged on each habitat during two months to compare growth performances and feeding status, estimated by fatty acid composition. Recruit assemblages differ from each habitat according to sediment grain-size composition and bathymetrical levels. Subtidal habitats, and especially Crepidula fornicata banks and Glycymeris glycymeris coarse sands, supported the highest species abundance and richness of recruits. All O. edulis juveniles fed on the same trophic resources but digestive glands of juveniles from C. fornicata banks were more concentrated in total fatty acids than those from subtidal G. glycymeris coarse sands and maerl banks. Our results depict the key role of subtidal and structured habitats, composed of ecosystem engineers, in enhancing bivalve recruitment and extending the bivalve population renewal. This study suggests that the crucial role of these habitats as bivalve nurseries must be integrated in management perspectives.

  16. L’INVASION DU RÉSEAU HYDROGRAPHIQUE FRANÇAIS PAR LES MOLLUSQUES CORBICULA SPP. MODALITÉ DE COLONISATION ET RÔLE PRÉPONDÉRANT DES CANAUX DE NAVIGATION.

    Directory of Open Access Journals (Sweden)

    BRANCOTTE V.

    2002-04-01

    Full Text Available Originaire d’Asie et d’Afrique, Corbicula a colonisé la plupart des bassins hydrographiques européens depuis 1980. A la faveur de la découverte de nouvelles stations, les auteurs mettent en évidence l’importance du rôle des canaux de navigation dans la propagation du mollusque, par la mise en connexion des bassins versants et l’existence d’un milieu particulièrement favorable à la biologie de l’espèce. Corbicula a pénétré en France par au moins sept axes différents, parmi lesquels le Rhin joue un rôle prépondérant.

  17. Anoxic survival potential of bivalves: (arte)facts.

    Science.gov (United States)

    de Zwaan, Albertus; Babarro, Jose M F; Monari, Marta; Cattani, Otello

    2002-03-01

    The anoxic survival time of the bivalves Chamelea gallina, Cerastoderma edule and Scapharca inaequivalvis from two different ecosystems and differing anoxia tolerances was studied in static (closed) and flow-through systems. The antibiotics chloramphenicol, penicillin and polymyxin were added, and molybdate (specific inhibitor of the process of sulfate reduction). Survival in (near) anoxic seawater of Chamelea was studied in a static system by comparing untreated seawater with autoclaved seawater and untreated clams with clams incubated in well-aerated seawater, containing the broad-spectrum antibiotic chloramphenicol, prior to the anoxic survival test. With untreated clams and natural seawater (median mortality time 2.4 days) a decrease in pH and exponential accumulation of sulfide and ammonium was observed in the anoxic medium, indicating excessive growth of (sulfate reducing) bacteria. In sterilized seawater LT50 (2.1 days) was not significantly different and again considerable amounts of ammonium and sulfide accumulated. However, pre-treatment of clams with chloramphenicol resulted in an increase of LT50 (11.0 days) by approximately fivefold. Accumulation of ammonium and sulfide was retarded, but was finally even stronger than in the medium containing untreated clams. Median mortality times were 2.5 and 2.4 days for Chamelea and 2.7 and 2.9 days for Cerastoderma for static and flow-through incubations, respectively. Addition of chloramphenicol increased strongly survival time in both systems with corresponding values of 11.0 and 16.3 days for Chamelea, and 6.4 and 6.5 days for Cerastoderma. LT50 of Scapharca in anoxic seawater was 14.4 days. Chloramphenicol and penicillin increased median survival time to 28.5 and 28.7 days, respectively, whereas polymyxin displayed no effect (LT50=13.6 days). Molybdate added to artificial sulfate free seawater blocked biotic sulfide formation, but did not improve survival time (LT50=13.7 days). Overall the results indicate

  18. Different carbon sources affect PCB accumulation by marine bivalves.

    Science.gov (United States)

    Laitano, M V; Silva Barni, M F; Costa, P G; Cledón, M; Fillmann, G; Miglioranza, K S B; Panarello, H O

    2016-02-01

    Pampean creeks were evaluated in the present study as potential land-based sources of PCB marine contamination. Different carbon and nitrogen sources from such creeks were analysed as boosters of PCB bioaccumulation by the filter feeder bivalve Brachidontes rodriguezii and grazer limpet Siphonaria lessoni. Carbon of different source than marine and anthropogenic nitrogen assimilated by organisms were estimated through their C and N isotopic composition. PCB concentration in surface sediments and mollusc samples ranged from 2.68 to 6.46 ng g(-1) (wet weight) and from 1074 to 4583 ng g(-1) lipid, respectively, reflecting a punctual source of PCB contamination related to a landfill area. Thus, despite the low flow of creeks, they should not be underestimated as contamination vectors to the marine environment. On the other hand, mussels PCB bioaccumulation was related with the carbon source uptake which highlights the importance to consider this factor when studying PCB distribution in organisms of coastal systems.

  19. Changing restoration rules: exotic bivalves interact with residence time and depth to control phytoplankton productivity

    Science.gov (United States)

    Lucas, Lisa V.; Thompson, Janet K.

    2012-01-01

    Non-native species are a prevalent ecosystem stressor that can interact with other stressors to confound resource management and restoration. We examine how interactions between physical habitat attributes and a particular category of non-native species (invasive bivalves) influence primary production in aquatic ecosystems. Using mathematical models, we show how intuitive relationships between phytoplankton productivity and controllable physical factors (water depth, hydraulic transport time) that hold in the absence of bivalves can be complicated—and even reversed—by rapid bivalve grazing. In light-limited environments without bivalves, shallow, hydrodynamically “slow” habitats should generally have greater phytoplankton biomass and productivity than deeper, “faster” habitats. But shallower, slower environments can be less productive than deeper, faster ones if benthic grazing is strong. Moreover, shallower and slower waters exhibit a particularly broad range of possible productivity outcomes that can depend on whether bivalves are present. Since it is difficult to predict the response of non-native bivalves to habitat restoration, outcomes for new shallow, slow environments can be highly uncertain. Habitat depth and transport time should therefore not be used as indicators of phytoplankton biomass and production where bivalve colonization is possible. This study provides for ecosystem management a particular example of a broad lesson: abiotic ecosystem stressors should be managed with explicit consideration of interactions with other major (including biotic) stressors. We discuss the applicability and management implications of our models and results for a range of aquatic system types, with a case study focused on the Sacramento-San Joaquin Delta (California, USA). Simple mathematical models like those used here can illuminate interactions between ecosystem stressors and provide process-based guidance for resource managers as they develop strategies

  20. First evidence of immunomodulation in bivalves under seawater acidification and increased temperature.

    Directory of Open Access Journals (Sweden)

    Valerio Matozzo

    Full Text Available Water acidification, temperature increases and changes in seawater salinity are predicted to occur in the near future. In such a global climate change (GCC scenario, there is growing concern for the health status of both wild and farmed organisms. Bivalve molluscs, an important component of coastal marine ecosystems, are at risk. At the immunological level, the ability of an organism to maintain its immunosurveillance unaltered under adverse environmental conditions may enhance its survival capability. To our knowledge, only a few studies have investigated the effects of changing environmental parameters (as predicted in a GCC scenario on the immune responses of bivalves. In the present study, the effects of both decreased pH values and increased temperature on the important immune parameters of two bivalve species were evaluated for the first time. The clam Chamelea gallina and the mussel Mytilus galloprovincialis, widespread along the coast of the Northwestern Adriatic Sea, were chosen as model organisms. Bivalves were exposed for 7 days to three pH values (8.1, 7.7 and 7.4 at two temperatures (22 and 28°C. Three independent experiments were carried out at salinities of 28, 34 and 40 PSU. The total haemocyte count, Neutral Red uptake, haemolymph lysozyme activity and total protein levels were measured. The results obtained demonstrated that tested experimental conditions affected significantly most of the immune parameters measured in bivalves, even if the variation pattern of haemocyte responses was not always linear. Between the two species, C. gallina appeared more vulnerable to changing pH and temperature than M. galloprovincialis. Overall, this study demonstrated that climate changes can strongly affect haemocyte functionality in bivalves. However, further studies are needed to clarify better the mechanisms of action of changing environmental parameters, both individually and in combination, on bivalve haemocytes.

  1. Determination of the recovery efficiency of cryptosporidium oocysts and giardia cysts from seeded bivalve mollusks.

    Science.gov (United States)

    Schets, Franciska M; van den Berg, Harold H J L; de Roda Husman, Ana Maria

    2013-01-01

    The intestinal parasites Cryptosporidium and Giardia are transmitted by water and food and cause human gastroenteritis. Filter-feeding bivalve mollusks, such as oysters and mussels, filter large volumes of water and thus concentrate such pathogens, which makes these bivalves potential vectors of disease. To assess the risk of infection from consumption of contaminated bivalves, parasite numbers and parasite recovery data are required. A modified immunomagnetic separation (IMS) procedure was used to determine Cryptosporidium oocyst and Giardia cyst numbers in individually homogenized oysters (Crassostrea gigas) and mussels (Mytilus edulis). About 12% of the commercial bivalves were positive, with low (oo)cyst numbers per specimen. The recovery efficiency of the IMS procedure was systematically evaluated. Experiments included seeding of homogenized bivalves and whole animals with 100 to 1,000 (oo)cysts. Both seeding procedures yielded highly variable recovery rates. Median Cryptosporidium recoveries were 7.9 to 21% in oysters and 62% in mussels. Median Giardia recoveries were 10 to 25% in oysters and 110% in mussels. Giardia recovery was significantly higher than Cryptosporidium recovery. (Oo)cysts were less efficiently recovered from seeded whole animals than from seeded homogenates, with median Cryptosporidium recoveries of 5.3% in oysters and 45% in mussels and median Giardia recoveries of 4.0% in oysters and 82% in mussels. Both bivalve homogenate seeding and whole animal seeding yielded higher (oo)cyst recovery in mussels than in oysters, likely because of the presence of less shellfish tissue in IMS when analyzing the smaller mussels compared with the larger oysters, resulting in more efficient (oo)cyst extraction. The data generated in this study may be used in the quantitative assessment of the risk of infection with Cryptosporidium or Giardia associated with the consumption of raw bivalve mollusks. This information may be used for making risk management

  2. The earliest post-paleozoic freshwater bivalves preserved in coprolites from the karoo basin, South Africa.

    Directory of Open Access Journals (Sweden)

    Adam M Yates

    Full Text Available BACKGROUND: Several clades of bivalve molluscs have invaded freshwaters at various times throughout Phanerozoic history. The most successful freshwater clade in the modern world is the Unionoida. Unionoids arose in the Triassic Period, sometime after the major extinction event at the End-Permian boundary and are now widely distributed across all continents except Antarctica. Until now, no freshwater bivalves of any kind were known to exist in the Early Triassic. PRINCIPAL FINDINGS: Here we report on a faunule of two small freshwater bivalve species preserved in vertebrate coprolites from the Olenekian (Lower Triassic of the Burgersdorp Formation of the Karoo Basin, South Africa. Positive identification of these bivalves is not possible due to the limited material. Nevertheless they do show similarities with Unionoida although they fall below the size range of extant unionoids. Phylogenetic analysis is not possible with such limited material and consequently the assignment remains somewhat speculative. CONCLUSIONS: Bivalve molluscs re-invaded freshwaters soon after the End-Permian extinction event, during the earliest part of the recovery phase during the Olenekian Stage of the Early Triassic. If the specimens do represent unionoids then these Early Triassic examples may be an example of the Lilliput effect. Since the oldest incontrovertible freshwater unionoids are also from sub-Saharan Africa, it is possible that this subcontinent hosted the initial freshwater radiation of the Unionoida. This find also demonstrates the importance of coprolites as microenvironments of exceptional preservation that contain fossils of organisms that would otherwise have left no trace.

  3. Persistent free radical ESR signals in marine bivalve tissues

    Energy Technology Data Exchange (ETDEWEB)

    Mehlorn, R.J. [California Univ., Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering; Mendez, A.T. [Fundacion Educativa Ana G. Mendez, Rio Piedras (Puerto Rico); Higashi, R. [California Univ., Bodega Bay, CA (United States). Bodega Marine Lab.; Fan, T. [California Univ., Davis, CA (United States)

    1992-08-01

    Freeze-dried homogenates of the oyster Crassostrea rhizophorae collected from waters in Puerto Rico near urban and industrial sites as well as at relatively pristine locations yielded electron spin resonance (ESR) spectra characteristic of free radicals as well as spectral components of transition metal ions, dominated by manganese. The magnitudes of these ESR signals and the concentrations of trace elements (determined by X-ray fluorescence) varied considerably among oyster samples, masking any potential correlation with polluted waters. Laboratory studies were initiated to identify the factors controlling the magnitudes of the tissue free radical ESR signals. Another mollusc, Mytilus californianus collected at the Bodega Marine laboratory in northern California, was fractionated into goneds and remaining tissue. Freeze-dried homogenates of both fractions exhibited ESR signals that increased gradually with time. ESR signals were observed in freeze-dried perchloric acid (PCA) precipitates of the homogenates, delipidated PCA precipitates, and in chloroform extracts of these precipitates. Acid hydrolysis to degrade proteins to amino acids produced a residue, which yielded much larger ESR free radical signals after freeze-drying. Freshly thawed homogenates of Crassostrea rhizophorae also exhibited ESR signals. A laboratory model of copper stress in Crassostrea rhizophorae was developed to study the effect of this transition metal on dssue free radicals. Preliminary results suggested that sublethal copper exposure had little effect on tissue fire radicals, except possibly for a signal enhancement in an oyster fraction that was enriched in kidney granules. Since kidney granules are known to accumulate heavy metals in mussels and probably other marine bivalves, this signal enhancement may prove to be an indicator of free radical processes associated with heavy metal deposition in molluscs.

  4. Environmental influence on population dynamics of the bivalve Anomalocardia brasiliana

    Science.gov (United States)

    Corte, Guilherme Nascimento; Coleman, Ross A.; Amaral, A. Cecília Z.

    2017-03-01

    Understanding how species respond to the environment in terms of population attributes (e.g. abundance, growth, mortality, fecundity, and productivity) is essential to protect ecologically and economically important species. Nevertheless, responses of macrobenthic populations to environmental features are overlooked due to the need of consecutive samplings and time-consuming measurements. We examined the population dynamics of the filter-feeding bivalve Anomalocardia brasiliana on a tidal flat over the course of one year to investigate the hypothesis that, as accepted for macrobenthic communities, populations inhabiting environments with low hydrodynamic conditions such as tidal flat should have higher attributes than populations inhabiting more energetic habitats (i.e. areas more influenced by wave energy such as reflective and intermediate beaches). This would be expected because the harsh conditions of more energetic habitats force organisms to divert more energy towards maintenance, resulting in lower population attributes. We found that A. brasiliana showed moderate growth and secondary production at the study area. Moreover the recruitment period was restricted to a few months. A comparison with previous studies showed that, contrary to expected, A. brasiliana populations from areas with low hydrodynamic conditions have lower abundance, growth, recruitment and turnover rate. It is likely that morphodynamic characteristics recorded in these environments, such as larger periods of air exposure and lower water circulation, may affect food conditions for filter-feeding species and increase competition. In addition, these characteristics may negatively affect macrobenthic species by enhancing eutrophication processes and anoxia. Overall, our results suggest that models accepted and applied at the macrobenthic community level might not be directly extended to A. brasiliana populations.

  5. A comparative study on the effects of barite, ilmenite and bentonite on four suspension feeding bivalves.

    Science.gov (United States)

    Strachan, Maia F; Kingston, Paul F

    2012-10-01

    The impact of drilling mud components on the filtration activity and survival of bivalve molluscs was investigated by exposing them to suspensions of 'standard' barite, finely milled barite, ilmenite and bentonite in sea water. Introduction of the components stimulated filtration activity in all four bivalves. In addition, the introduction of standard barite and ilmenite both had lethal effects, with none of the bivalves surviving the full duration of the experiments. In-vivo observations of the gill surfaces provided direct evidence of physical damage caused by the administration of barite and ilmenite. A marked difference between filtration activity and survival of animals dosed with 'standard' barite and 'fine' barite suggests that the observed effects were primarily caused by physical interference with gill function. The results also suggest that the use of fine barite in offshore drilling may provide a more favourable environmental impact profile than the use of ilmenite.

  6. Saturation-state sensitivity of marine bivalve larvae to ocean acidification

    Science.gov (United States)

    Waldbusser, George G.; Hales, Burke; Langdon, Chris J.; Haley, Brian A.; Schrader, Paul; Brunner, Elizabeth L.; Gray, Matthew W.; Miller, Cale A.; Gimenez, Iria

    2015-03-01

    Ocean acidification results in co-varying inorganic carbon system variables. Of these, an explicit focus on pH and organismal acid-base regulation has failed to distinguish the mechanism of failure in highly sensitive bivalve larvae. With unique chemical manipulations of seawater we show definitively that larval shell development and growth are dependent on seawater saturation state, and not on carbon dioxide partial pressure or pH. Although other physiological processes are affected by pH, mineral saturation state thresholds will be crossed decades to centuries ahead of pH thresholds owing to nonlinear changes in the carbonate system variables as carbon dioxide is added. Our findings were repeatable for two species of bivalve larvae could resolve discrepancies in experimental results, are consistent with a previous model of ocean acidification impacts due to rapid calcification in bivalve larvae, and suggest a fundamental ocean acidification bottleneck at early life-history for some marine keystone species.

  7. Characterization of the mantle transcriptome in bivalves: Pecten maximus, Mytilus edulis and Crassostrea gigas.

    Science.gov (United States)

    Yarra, Tejaswi; Gharbi, Karim; Blaxter, Mark; Peck, Lloyd S; Clark, Melody S

    2016-06-01

    The calcareous shells secreted by bivalve molluscs display diverse and species specific structural compositions, which indicates possible divergent biomineralization processes. Thus, studying multiple mollusc species will provide a more comprehensive understanding of shell formation. Here, the transcriptomes of the mantle tissues responsible for shell deposition were characterized in three commercially relevant bivalve species. Using high-throughput sequencing and bioinformatics tools, de novo transcriptome assemblies of mantle tissues were generated for the mussel Mytilus edulis, the oyster Crassostrea gigas and the scallop Pecten maximus. These transcriptomes were annotated, and contigs with similarity to proteins known to have shell formation roles in other species were identified. Comparison of the shell formation specific proteins in the three bivalves indicates the possibility of species specific shell proteins.

  8. Arsenic and trace metals in commercially important bivalves, Anadara granosa and Paphia undulata

    Energy Technology Data Exchange (ETDEWEB)

    Mat, I. (Univ. of Malaya, Kuala Lumpur (Malaysia))

    1994-06-01

    The semi-culture of marine bivalves particularly Anadara granosa is of considerable economic importance in Malaysia. Currently, about 4-5000 ha of mudflats along the west coast are utilized for this purpose. Therefore, contamination of the highly productive mudflats with heavy metals tend to be accumulated in the filter feeding organisms such as bivalve molluscs which often serve as important environmental sinks of heavy metals. Bivalve molluscs, A. granosa and Paphia undulata are commercially important seafoods and popular among the locals in Malaysia. With this point in mind, it is intended to evaluate the concentration levels of arsenic as well as trace metals (Co, Cu, Ni, Cd, Zn, Cr and Pb) in both species derived from retail outlets in the city of Kuala Lumpur. Although this analysis may not indicate the site of capture but may act as a direct check on the contamination of seafoods available to the consumers. 17 refs., 2 tabs.

  9. Approaches for evaluating the effects of bivalve filter feeding on nutrient dynamics in Puget Sound, Washington

    Science.gov (United States)

    Konrad, Christopher P.

    2014-01-01

    Marine bivalves such as clams, mussels, and oysters are an important component of the food web, which influence nutrient dynamics and water quality in many estuaries. The role of bivalves in nutrient dynamics and, particularly, the contribution of commercial shellfish activities, are not well understood in Puget Sound, Washington. Numerous approaches have been used in other estuaries to quantify the effects of bivalves on nutrient dynamics, ranging from simple nutrient budgeting to sophisticated numerical models that account for tidal circulation, bioenergetic fluxes through food webs, and biochemical transformations in the water column and sediment. For nutrient management in Puget Sound, it might be possible to integrate basic biophysical indicators (residence time, phytoplankton growth rates, and clearance rates of filter feeders) as a screening tool to identify places where nutrient dynamics and water quality are likely to be sensitive to shellfish density and, then, apply more sophisticated methods involving in-situ measurements and simulation models to quantify those dynamics.

  10. Spatial and temporal distribution of mercury and methylmercury in bivalves from the French coastline.

    Science.gov (United States)

    Briant, N; Chouvelon, T; Martinez, L; Brach-Papa, C; Chiffoleau, J F; Savoye, N; Sonke, J; Knoery, J

    2017-01-30

    Marine mercury (Hg) concentrations have been monitored in the French coastline for the last half a century using bivalves. The analyses presented in this study concerned 192 samples of bivalves (mussels: Mytilus edulis and Mytilus galloprovincialis and oysters: Crassostrea gigas and Isognomon alatus) from 77 sampling stations along the French coast and in the French Antilles sea. The goals of this study were to assess MeHg levels in various common bivalves from French coastline, and to identify possible geographic, taxonomic or temporal variations of concentrations. We show that the evolution of methylmercury (MeHg) concentrations covary with total mercury (HgT) concentrations. Moreover, in most of the study sites, HgT concentrations have not decreased since 1987, despite regulations to decrease or ban mercury used for anthropic activities.

  11. Pathogenic marine microbes influence the effects of climate change on a commercially important tropical bivalve.

    Science.gov (United States)

    Turner, Lucy M; Alsterberg, Christian; Turner, Andrew D; Girisha, S K; Rai, Ashwin; Havenhand, Jonathan N; Venugopal, M N; Karunasagar, Indrani; Godhe, Anna

    2016-01-01

    There is growing evidence that climate change will increase the prevalence of toxic algae and harmful bacteria, which can accumulate in marine bivalves. However, we know little about any possible interactions between exposure to these microorganisms and the effects of climate change on bivalve health, or about how this may affect the bivalve toxin-pathogen load. In mesocosm experiments, mussels, Perna viridis, were subjected to simulated climate change (warming and/or hyposalinity) and exposed to harmful bacteria and/or toxin-producing dinoflagellates. We found significant interactions between climate change and these microbes on metabolic and/or immunobiological function and toxin-pathogen load in mussels. Surprisingly, however, these effects were virtually eliminated when mussels were exposed to both harmful microorganisms simultaneously. This study is the first to examine the effects of climate change on determining mussel toxin-pathogen load in an ecologically relevant, multi-trophic context. The results may have considerable implications for seafood safety.

  12. An integrated ecosystem approach for assessing the potential role of cultivated bivalve shells as part of the carbon trading system

    NARCIS (Netherlands)

    Filgueira, R.; Byron, C.J.; Comeau, L.A.; Jansen, H.M.; Smaal, A.C.

    2015-01-01

    The role of bivalve mariculture in the CO2 cycle has been commonly evaluated as the balance between respiration, shell calcium carbonate sequestration and CO2 release during biogenic calcification. However, this approach neglects the ecosystem implications of cultivating bivalves at high densities,

  13. Facilitation on an intertidal mudflat : the effect of siphon nipping by flatfish on burying depth of the bivalve Macoma balthica

    NARCIS (Netherlands)

    de Goeij, P; Luttikhuizen, PC; van der Meer, J; Piersma, T

    2001-01-01

    During deposit feeding on benthic microalgae, the siphon of buried tellinid bivalves like Macoma balthica is vulnerable to nipping by plaice Pleuronectes platessa and other flatfish. We experimentally tested the hypothesis that siphon nippers facilitate predation on the entire bivalve (by shorebirds

  14. An integrated ecosystem approach for assessing the potential role of cultivated bivalve shells as part of the carbon trading system

    DEFF Research Database (Denmark)

    Filgueira, Ramón; Byron, C.J.; Comeau, L.A.;

    2015-01-01

    The role of bivalve mariculture in the CO2 cycle has been commonly evaluated as the balance between respiration, shell calcium carbonate sequestration and CO2 release during biogenic calcification. However, this approach neglects the ecosystem implications of cultivating bivalves at high densitie...

  15. Bivalve aquaculture-environment interactions in the context of climate change.

    Science.gov (United States)

    Filgueira, Ramón; Guyondet, Thomas; Comeau, Luc A; Tremblay, Réjean

    2016-12-01

    Coastal embayments are at risk of impacts by climate change drivers such as ocean warming, sea level rise and alteration in precipitation regimes. The response of the ecosystem to these drivers is highly dependent on their magnitude of change, but also on physical characteristics such as bay morphology and river discharge, which play key roles in water residence time and hence estuarine functioning. These considerations are especially relevant for bivalve aquaculture sites, where the cultured biomass can alter ecosystem dynamics. The combination of climate change, physical and aquaculture drivers can result in synergistic/antagonistic and nonlinear processes. A spatially explicit model was constructed to explore effects of the physical environment (bay geomorphic type, freshwater inputs), climate change drivers (sea level, temperature, precipitation) and aquaculture (bivalve species, stock) on ecosystem functioning. A factorial design led to 336 scenarios (48 hydrodynamic × 7 management). Model outcomes suggest that the physical environment controls estuarine functioning given its influence on primary productivity (bottom-up control dominated by riverine nutrients) and horizontal advection with the open ocean (dominated by bay geomorphic type). The intensity of bivalve aquaculture ultimately determines the bivalve-phytoplankton trophic interaction, which can range from a bottom-up control triggered by ammonia excretion to a top-down control via feeding. Results also suggest that temperature is the strongest climate change driver due to its influence on the metabolism of poikilothermic organisms (e.g. zooplankton and bivalves), which ultimately causes a concomitant increase of top-down pressure on phytoplankton. Given the different thermal tolerance of cultured species, temperature is also critical to sort winners from losers, benefiting Crassostrea virginica over Mytilus edulis under the specific conditions tested in this numerical exercise. In general, it is

  16. A Darriwilian (Middle Ordovician bivalve-dominated molluscan fauna from the Stairway Sandstone, Amadeus Basin, central Australia

    Directory of Open Access Journals (Sweden)

    Kristian G. Jakobsen

    2016-12-01

    Full Text Available A bivalve-dominated molluscan fauna is described from the Darriwilian (Middle Ordovician Stairway Sandstone, Amadeus Basin, central Australia. The fauna comprises 16 species of bivalves and rostroconchs plus six gastropod species which are treated under open nomenclature. Two new bivalves, Sthenodonta paenesymmetrica sp. nov. and Modiolopsis pojetai sp. nov., are described. The relatively low-diverse molluscan fauna constitutes around 62% of the total benthic macrofauna. Approximately 75% of the molluscs comprise bivalves, especially nuculoids, which were biogeographically restricted to low latitudes during the Ordovician. The molluscan assemblage displays a very high degree of endemism at species level, though the bivalve Sthenodonta eastii also occurs in the Georgina Basin farther to the northeast. This indicates a possible marine connective seaway between the Georgina and Amadeus basins during the Darriwilian. Nuculites, Cyrtodonta, and Modiolopsis are cosmopolitan and previously reported from North China, Avalonia, and Southern Gondwana.

  17. Heavy metals in bivalves collected from river estuaries of Thailand. [Perna viridis

    Energy Technology Data Exchange (ETDEWEB)

    Menasveta, P.; Cheevapora, V.; Wongwit, C.

    1984-01-01

    This investigation was undertaken to determine the levels of lead, zinc, copper, cadmium, and mercury in five species of bivalves collected from six river estuaries of Thailand during July 1978 to January 1979. The in situ bioassay for studying heavy metals uptake by green mussels (Perna viridis) was also conducted at the Chao Phraya river estuary during February 1980 to March 1981. The results revealed high contamination of lead in mussels during the period of river run-off. The factors that might contribute to this incidence were discussed. Contaminations of the other four metals in bivalves did not show great variation and they were still within the acceptable limits.

  18. Microcystin uptake and biochemical responses in the freshwater clam Corbicula leana P. exposed to toxic and non-toxic Microcystis aeruginosa: Evidence of tolerance to cyanotoxins

    Directory of Open Access Journals (Sweden)

    Thanh-Luu Pham

    2015-01-01

    Full Text Available We investigated the accumulation and adverse effects of toxic and non-toxic Microcystis in the edible clam Corbicula leana. Treated clams were exposed to toxic Microcystis at 100 μg of MC (microcystin-LReq L−1 for 10 days. The experimental organism was then placed in toxin-free water and fed on non-toxic Microcystis for the following 10 days for depuration. Filtering rates (FRs by C. leana of toxic and non-toxic Microcystis and of the green alga Chlorella vulgaris as a control were estimated. Adverse effects were evaluated though the activity of catalase (CAT, superoxide dismutase (SOD and glutathione S-transferase (GST. Clam accumulated MCs (up to 12.7 ± 2.5 μg g−1 dry weight (DW of free MC and 4.2 ± 0.6 μg g−1 DW of covalently bound MC. Our results suggest that although both toxic and non-toxic cyanobacteria caused adverse effects by inducing the detoxification and antioxidant defense system, the clam was quite resistant to cyanotoxins. The estimated MC concentration in C. leana was far beyond the World Health Organization's (WHO provisional tolerable daily intake (0.04 μg kg−1 day−1, suggesting that consuming clams harvested during cyanobacterial blooms carries a high health risk.

  19. Shell growth and environmental control of methanophyllic Thyasirid bivalves from Svalbard cold seeps

    Science.gov (United States)

    Carroll, Michael; Åström, Emmelie; Ambrose, William; Locke, William; Oliver, Graham; Hong, Wei-Li; Carroll, JoLynn

    2016-04-01

    The analysis of molluscan shell material (sclerochronology) can provide information about an organism's age, growth history, and environmental conditions during its lifetime. Bivalve molluscs are common members of hydrothermal vents and methane cold seeps communities where, supported by chemosynthetic symbionts, they can reach high density and biomass. But little is known about methane-associated bivalve populations inhabiting high-Arctic cold seeps, and sclerochronological analysis of methane-influenced bivalves is rare. We measured growth rates and elemental and isotopic shell signatures in a newly discovered species of bivalve (Thyasiridae) from cold seeps at 350-390m depth southwest of Svalbard. First discovered in 2014, recently described shells of Thyasira capitanea sp.nov. were found at 2 independent seep systems in Storfjordrenna. Mean shell carbon isotopic ratios from inorganic δ13C (mean = -4.8‰) and organic δ13C (mean = -26.9‰) fractions clearly indicate a methane influenced habitat and food source for these organisms. Shell mineral ratios (Li/Ca, Mg/Ca, Mn/Ca, Fe/Ca, Sr/Ca, Ba/Ca, Pb/Ca) sampled along the axis of growth with laser-ablated ICP-MS exhibit variability through time and between sites, suggesting that concentrations of these elements that may be affected by methane emissions. The mineralogical data also elucidates the internal pattern of shell deposition and growth checks, and combined with the isotopic and growth rate data, enables us to interpret the temporal history of methane release from these locations.

  20. Bivalve aquaculture transfers in Atlantic Europe. Part A: Transfer activities and legal framework

    DEFF Research Database (Denmark)

    Muehlbauer, F.; Fraser, D.; Brenner, M.

    2014-01-01

    Intentional transfers of numerous bivalve species have had a long tradition and are commonly conducted along the European Atlantic coast. However numerous studies have concluded that intentional transfer of species for aquaculture purposes is one of the most principal vectors for the introduction...

  1. CYP1A-immunopositive proteins in bivalves identified as cytoskeletal and major vault proteins

    DEFF Research Database (Denmark)

    Grøsvik, Bjørn Einar; Jonsson, Henrik; Rodríguez-Ortega, Manuel J;

    2006-01-01

    To identify possible CYP1A-immunopositive proteins in bivalves, we used anti-fish CYP1A antibodies combined with one- and two-dimensional gel electrophoresis and mass spectrometry, and found that two of the main CYP1A-immunopositive proteins in digestive gland of Mytilus edulis, were cytoskeletal...

  2. Validation and comparison of methods for enumeration of faecal coliforms and Escherichia coli in bivalve molluscs

    NARCIS (Netherlands)

    Mooijman KA; Poelman M; Stegeman H; Warmerdam C; Teunis PFM; Roda Husman AM de; RIKILT; MGB

    2007-01-01

    The main result of the validation study to show the equivalence of two methods for the enumeration of faecal coliforms in bivalve molluscs is that the plate count method on Mac Conkey agar was indeed found to be equivalent to the MPN method. Meaning that the Netherlands fulfilled the demands as stat

  3. A predatory bivalved euarthropod from the Cambrian (Stage 3) Xiaoshiba Lagerstätte, South China

    Science.gov (United States)

    Yang, Jie; Ortega-Hernández, Javier; Lan, Tian; Hou, Jin-Bo; Zhang, Xi-Guang

    2016-06-01

    Bivalved euarthropods represent a conspicuous component of exceptionally-preserved fossil biotas throughout the Lower Palaeozoic. However, most of these taxa are known from isolated valves, and thus there is a limited understanding of their morphological organization and palaeoecology in the context of early animal-dominated communities. The bivalved euarthropod Clypecaris serrata sp. nov., recovered from the Cambrian (Stage 3) Hongjingshao Formation in Kunming, southern China, is characterized by having a robust first pair of raptorial appendages that bear well-developed ventral-facing spines, paired dorsal spines on the trunk, and posteriorly oriented serrations on the anteroventral margins of both valves. The raptorial limbs of C. serrata were adapted for grasping prey employing a descending stroke for transporting it close the mouth, whereas the backwards-facing marginal serrations of the bivalved carapace may have helped to secure the food items during feeding. The new taxon offers novel insights on the morphology of the enigmatic genus Clypecaris, and indicates that the possession of paired dorsal spines is a diagnostic trait of the Family Clypecarididae within upper stem-group Euarthropoda. C. serrata evinces functional adaptations for an active predatory lifestyle within the context of Cambrian bivalved euarthropods, and contributes towards the better understanding of feeding diversity in early ecosystems.

  4. Burrowing Behavior of a Deposit Feeding Bivalve Predicts Change in Intertidal Ecosystem State

    NARCIS (Netherlands)

    Compton, T.J.; Bodnar, W.; Koolhaas, A.; Dekinga, A.; Holthuijsen, S.; Ten Horn, J.; McSweeney, N.; van Gils, J.A.; Piersma, T,

    2016-01-01

    Behavior has a predictive power that is often underutilized as a tool for signaling ecological change. The burrowing behavior of the deposit feeding bivalve Macoma balthica reflects a typical food-safety trade-off. The choice to live close to the sediment surface comes at a risk of predation and is

  5. Burrowing behavior of a deposit feeding bivalve predicts change in intertidal ecosystem state

    NARCIS (Netherlands)

    Compton, Tanya J.; Bodnar, Wanda; Koolhaas, Anita; Dekinga, Anne; Holthuijsen, Sander; ten Horn, Job; McSweeney, Niamh; van Gils, Jan; Piersma, Theunis

    2016-01-01

    Behavior has a predictive power that is often underutilized as a tool for signaling ecological change. The burrowing behavior of the deposit feeding bivalve Macoma balthica reflects a typical food-safety trade-off. The choice to live close to the sediment surface comes at a risk of predation and is

  6. Bivalve grazing, nutrient cycling and phytoplankton dynamics in an estuarine ecosystem.

    NARCIS (Netherlands)

    Prins, T.C.

    1996-01-01

    This thesis has considered the impact of the suspension feeding bivalve Mytilusedulis on nutrient cycling and phytoplankton in an estuarine ecosystem. The research was started within the framework of an extensive research project with the objective to evaluate the changes in the Oosterschelde ecosys

  7. Temperature dependent larval occurrence and spat settlement of the invasive brackish water bivalve

    NARCIS (Netherlands)

    van der Gaag, M.; van der Velde, G.; Wijnhoven, S.; Rajagopal, S.

    2014-01-01

    Mytilopsis leucophaeata, an invasive bivalve species, causes fouling problems by settling on submerged constructions and in cooling water circuits in brackish water. To predict spat fall we studied the larval occurrence and settlement of this species in the brackish Noordzeekanaal canal in the Nethe

  8. Novas ocorrências de gastrópodes e bivalves marinhos no Brasil (Mollusca

    Directory of Open Access Journals (Sweden)

    Absalão Ricardo Silva

    2003-01-01

    Full Text Available The gastropods Costaclis egregia (Dall, 1889, Thaleia nisonis (Dall, 1889, Tjaernoeia michaeli Engl, 2001 and the bivalves Bathyarca sp., Myonera aff. ruginosa (Jeffreys, 1882 are recorded for the first time in Brazilian waters. This paper presents a brief description of these species and also include ilustrations.

  9. Fossil predation: did some clavilithine fasciolariid gastropods employ valve-wedging to feed on bivalves?

    NARCIS (Netherlands)

    Vermeij, Geerat J.

    2015-01-01

    Several gastropods, including members of the Busyconinae, wedge or chip bivalve prey by inserting the outer lip between the valves. This habit, which is associated with an abapically downwardly convex outer lip, often results in breakage and subsequent repair of the lip. I tested the hypothesis that

  10. Mosaic haploid-diploid embryos and polyspermy in the tellinid bivalve Macoma balthica

    NARCIS (Netherlands)

    Luttikhuizen, PC; Pijnacker, LP

    2002-01-01

    We investigated meiosis, fertilization, and early development in eggs of the tellinid bivalve Macoma balthica (L.), which has external fertilization. Meiosis is standard but polyspermy is found to be very common. In all eight crosses examined, mosaic embryos consisting of a mixture of diploid (2n =

  11. Dynamic Energy Budget model parameter estimation for the bivalve Mytilus californianus: Application of the covariation method

    Science.gov (United States)

    Matzelle, A.; Montalto, V.; Sarà, G.; Zippay, M.; Helmuth, B.

    2014-11-01

    Dynamic Energy Budget (DEB) models serve as a powerful tool for describing the flow of energy through organisms from assimilation of food to utilization for maintenance, growth and reproduction. The DEB theory has been successfully applied to several bivalve species to compare bioenergetic and physiological strategies for the utilization of energy. In particular, mussels within the Mytilus edulis complex (M. edulis, M. galloprovincialis, and M. trossulus) have been the focus of many studies due to their economic and ecological importance, and their worldwide distribution. However, DEB parameter values have never been estimated for Mytilus californianus, a species that is an ecological dominant on rocky intertidal shores on the west coast of North America and which likely varies considerably from mussels in the M. edulis complex in its physiology. We estimated a set of DEB parameters for M. californianus using the covariation method estimation procedure and compared these to parameter values from other bivalve species. Model parameters were used to compare sensitivity to environmental variability among species, as a first examination of how strategies for physiologically contending with environmental change by M. californianus may differ from those of other bivalves. Results suggest that based on the parameter set obtained, M. californianus has favorable energetic strategies enabling it to contend with a range of environmental conditions. For instance, the allocation fraction of reserve to soma (κ) is among the highest of any bivalves, which is consistent with the observation that this species can survive over a wide range of environmental conditions, including prolonged periods of starvation.

  12. Nutritional and reproductive strategies in a chemsoymbiotic bivalve living in a tropical intertidal seagrass bed

    NARCIS (Netherlands)

    van der Geest, Matthijs; Sall, Amadou Abderahmane; Ely, SIdi Ould; Nauta, Reindert W.; Gils, Jan A. van; Piersma, Theunis

    2014-01-01

    Sulphide-oxidizing endosymbiont-bearing bivalves often dominate the infauna of seagrass-covered sediments, where they control sulphide levels and contribute to carbon cycling by feeding on chemosynthetically fixed carbon and suspended particulate organic matter (SPOM). Previous studies from temperat

  13. Nutritional and reproductive strategies in a chemosymbiotic bivalve living in a tropical intertidal seagrass bed

    NARCIS (Netherlands)

    van der Geest, M.; Sall, A.A.; Ely, S.O.; Nauta, R.W.; van Gils, J.A.; Piersma, T.

    2014-01-01

    Sulphide-oxidizing endosymbiont-bearing bivalves often dominate the infauna of seagrass-covered sediments, where they control sulphide levels and contribute to carbon cycling by feeding on chemosynthetically fixed carbon and suspended particulate organic matter (SPOM). Previous studies from temperat

  14. A molecular phylogeny of bivalve mollusks: ancient radiations and divergences as revealed by mitochondrial genes.

    Directory of Open Access Journals (Sweden)

    Federico Plazzi

    Full Text Available BACKGROUND: Bivalves are very ancient and successful conchiferan mollusks (both in terms of species number and geographical distribution. Despite their importance in marine biota, their deep phylogenetic relationships were scarcely investigated from a molecular perspective, whereas much valuable work has been done on taxonomy, as well as phylogeny, of lower taxa. METHODOLOGY/PRINCIPAL FINDINGS: Here we present a class-level bivalve phylogeny with a broad sample of 122 ingroup taxa, using four mitochondrial markers (MT-RNR1, MT-RNR2, MT-CO1, MT-CYB. Rigorous techniques have been exploited to set up the dataset, analyze phylogenetic signal, and infer a single final tree. In this study, we show the basal position of Opponobranchia to all Autobranchia, as well as of Palaeoheterodonta to the remaining Autobranchia, which we here propose to call Amarsipobranchia. Anomalodesmata were retrieved as monophyletic and basal to (Heterodonta + Pteriomorphia. CONCLUSIONS/SIGNIFICANCE: Bivalve morphological characters were traced onto the phylogenetic trees obtained from the molecular analysis; our analysis suggests that eulamellibranch gills and heterodont hinge are ancestral characters for all Autobranchia. This conclusion would entail a re-evaluation of bivalve symplesiomorphies.

  15. In situ method for measurements of community clearance rate on shallow water bivalve populations

    DEFF Research Database (Denmark)

    Hansen, Benni W.; Dolmer, Per; Vismann, Bent

    2011-01-01

    with an air lift connected to a SCUBA diver pressure tank generating a continuous and gentle water circulation. This ensures a complete mixture of suspended particles, and thereby, a maximum filtration by the bivalves. An in situ fluorometer was mounted to record plant pigment reduction due to mussel...

  16. Draft Genome Sequence of the Emerging Bivalve Pathogen Vibrio tubiashii subsp. europaeus.

    Science.gov (United States)

    Spinard, Edward J; Dubert, Javier; Nelson, David R; Gomez-Chiarri, Marta; Barja, Juan L

    2016-07-28

    Vibrio tubiashii subsp. europaeus is a bivalve pathogen isolated during episodes of mortality affecting larval cultures in different shellfish hatcheries. Here, we announce the draft genome sequence of the type strain PP-638 and describe potential virulence factors, which may provide insight into the mechanism of pathogenicity.

  17. Modiolarca lateralis (Pteryomorphia: Mytilidae: bivalve associated to six species of ascidians from Bocas del Toro, Panama

    Directory of Open Access Journals (Sweden)

    Juan I Cañete

    2013-11-01

    Full Text Available We describe the presence of the bivalve Modiolarca lateralis (Say, 1822 in six tropical ascidians Ascidia curvata, A. sydneiensis, A. panamensis, A. interrupta, Herdmania pallida and Polycarpa spongiabilis collected at depths of 1-3 m on coral reefs, mangrove roots and dock supports in Almirante Bay, Bocas del Toro, Panama (9°18'N, 82°13'W during June-July 2011. Bivalve prevalence varied between 9-30% across species, but was mainly associated with A. panamensis, P. spongiabilis and A. interrupta. Prevalence seems to be influenced by tunic thickness rather than by the ascidian size. Bivalves varied in size (0.6-11 mm shell length, with the smallest individual found in A. sydneiensis. There were only one or two bivalves per ascidians, although a maximum of 18 was found in one A. panamensis. M. lateralis seems to behave similarly to its temperate counterparts: it has a variety of hosts, occurs mainly in the anterior region of the ascidians, and has a variable abundance per host.

  18. 76 FR 65200 - Risk Assessment on Norovirus in Bivalve Molluscan Shellfish: Request for Comments and for...

    Science.gov (United States)

    2011-10-20

    ... preventive practices and controls, food preparation and consumption practices, and the relationship between... thousands of cases in Canada annually (Refs. 2 to 4). The viruses can be transmitted through consumption of... consumption have been traced to contamination during growth and harvest (Refs. 1 and 6). Bivalve...

  19. Freshwater bivalve mollusca (unionidae, sphaeriidae, corbiculidae) of the Savannah River Plant, South Carolina

    Energy Technology Data Exchange (ETDEWEB)

    Britton, J.C.; Fuller, S.L.H.

    1980-11-01

    A guide to freshwater bivalve molluscs found at the Savannah River Plant is presented. A dichotomous taxonomic key is provided to common forms and to unreported species whose geographic distributions include nearby localities. Discussions of ecology, life history, larval hosts, and other pertinent information is provided. (ACR)

  20. Monobrachium parasitum (Cnidaria: Hydrozoa) epizoic on antarctic bivalves and its bipolarity

    NARCIS (Netherlands)

    Jarms, G.; Mühlenhardt-Siegel, U.

    1998-01-01

    During antarctic macrozoobenthos research, colonies of Monobrachium were found on small bivalves. The species problem of the genus Monobrachium is discussed and it is stated that there are three species. However, the widespread species Monobrachium parasitum might be a species-complex comprising sev

  1. An overview of chemosynthetic symbioses in bivalves from the North Atlantic and Mediterranean Sea

    Science.gov (United States)

    Duperron, S.; Gaudron, S. M.; Rodrigues, C. F.; Cunha, M. R.; Decker, C.; Olu, K.

    2013-05-01

    Deep-sea bivalves found at hydrothermal vents, cold seeps and organic falls are sustained by chemosynthetic bacteria that ensure part or all of their carbon nutrition. These symbioses are of prime importance for the functioning of the ecosystems. Similar symbioses occur in other bivalve species living in shallow and coastal reduced habitats worldwide. In recent years, several deep-sea species have been investigated from continental margins around Europe, West Africa, eastern Americas, the Gulf of Mexico, and from hydrothermal vents on the Mid-Atlantic Ridge. In parallel, numerous, more easily accessible shallow marine species have been studied. Herein we provide a summary of the current knowledge available on chemosymbiotic bivalves in the area ranging west-to-east from the Gulf of Mexico to the Sea of Marmara, and north-to-south from the Arctic to the Gulf of Guinea. Characteristics of symbioses in 53 species from the area are summarized for each of the five bivalve families documented to harbor chemosynthetic symbionts (Mytilidae, Vesicomyidae, Solemyidae, Thyasiridae and Lucinidae). Comparisons are made between the families, with special emphasis on ecology, life cycle, and connectivity. Chemosynthetic symbioses are a major adaptation to ecosystems and habitats exposed to reducing conditions. However, relatively little is known regarding their diversity and functioning, apart from a few "model species" on which effort has focused over the last 30 yr. In the context of increasing concern about biodiversity and ecosystems, and increasing anthropogenic pressure on oceans, we advocate a better assessment of the diversity of bivalve symbioses in order to evaluate the capacities of these remarkable ecological and evolutionary units to withstand environmental change.

  2. An overview of chemosynthetic symbioses in bivalves from the North Atlantic and Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    S. Duperron

    2012-11-01

    Full Text Available Deep-sea bivalves found at hydrothermal vents, cold seeps and organic falls are sustained by chemosynthetic bacteria which ensure part or all of their carbon nutrition. These symbioses are of prime importance for the functioning of the ecosystems. Similar symbioses occur in other bivalve species living in shallow and coastal reduced habitats worldwide. In recent years, several deep-sea species have been investigated from continental margins around Europe, West Africa, East America, the Gulf of Mexico, and from hydrothermal vents on the Mid-Atlantic Ridge. In parallel, numerous more easily accessible shallow marine species were studied. We here provide a summary of the current knowledge available on chemosymbiotic bivalves in the area ranging west-to-east from the Gulf of Mexico to Marmara Sea, and north-to-south from the Arctic to the Gulf of Guinea. Characteristics of symbioses in 51 species from the area are summarized for each of the five bivalve families documented to harbor chemosynthetic symbionts (Mytilidae, Vesicomyidae, Solemyidae, Thyasiridae and Lucinidae, and compared among families with special emphasis on ecology, life cycle, and connectivity. Chemosynthetic symbioses are a major adaptation to ecosystems and habitats exposed to reducing conditions, yet relatively little is known regarding their diversity and functioning apart from a few "model species" on which effort has focused over the last 30 yr. In the context of increasing concern about biodiversity and ecosystems, and increasing anthropogenic pressure on Oceans, we advocate for a better assessment of bivalve symbioses diversity in order to evaluate the capacities of these remarkable ecological and evolutionary units to withstand environmental change

  3. How predictable is high bivalve recruitment in the Wadden Sea after a severe winter?

    Science.gov (United States)

    Strasser, Matthias; Dekker, Rob; Essink, Karel; Günther, Carmen-Pia; Jaklin, Sandra; Kröncke, Ingrid; Madsen, Poul Brinch; Michaelis, Hermann; Vedel, Grace

    2003-02-01

    Higher than average recruitment among bivalves on the intertidal flats of the Wadden Sea was often observed after severe winters in the period 1940-1995. The occurrence of another severe winter in 1995/96 prompted us to test the hypothesis of severe winters leading to universally high bivalve recruitment on a large geographic scale (500 km coastline) in temperate shallow waters. We analysed data sets on bivalve abundance from seven areas in the Dutch, German and Danish Wadden Sea. The longer data sets showed generally higher bivalve recruitment in the 1970s and 1980s than in the 1990s which may be related to the near absence of severe winters since 1987. Considering the period 1988 onwards (the longest possible period in which 1995/96 was the only severe winter), recruitment of Cerastoderma edule was in 1996 - in agreement with our hypothesis - above average in all seven areas investigated. In contrast, recruitment of Macoma balthica and Mya arenaria was for the same period above average only in the southern Wadden Sea (south-west of Jade Bay) but not in the northern Wadden Sea (north of Eiderstedt peninsula). These regional differences may be related to (i) the different topography of the northern Wadden Sea (with barrier islands west of the mainland) compared to the southern Wadden Sea (with barrier islands north of the mainland) and subsequent differential effects of wind-induced currents on bivalve recruitment, (ii) differences in biotic factors such as standing stocks, larval supply or epibenthic predation or (iii) changes in environmental conditions. Our results demonstrate that large-scale comparisons along coasts are an indispensable addition to insights derived from local studies alone.

  4. An overview of chemosynthetic symbioses in bivalves from the North Atlantic and Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    S. Duperron

    2013-05-01

    Full Text Available Deep-sea bivalves found at hydrothermal vents, cold seeps and organic falls are sustained by chemosynthetic bacteria that ensure part or all of their carbon nutrition. These symbioses are of prime importance for the functioning of the ecosystems. Similar symbioses occur in other bivalve species living in shallow and coastal reduced habitats worldwide. In recent years, several deep-sea species have been investigated from continental margins around Europe, West Africa, eastern Americas, the Gulf of Mexico, and from hydrothermal vents on the Mid-Atlantic Ridge. In parallel, numerous, more easily accessible shallow marine species have been studied. Herein we provide a summary of the current knowledge available on chemosymbiotic bivalves in the area ranging west-to-east from the Gulf of Mexico to the Sea of Marmara, and north-to-south from the Arctic to the Gulf of Guinea. Characteristics of symbioses in 53 species from the area are summarized for each of the five bivalve families documented to harbor chemosynthetic symbionts (Mytilidae, Vesicomyidae, Solemyidae, Thyasiridae and Lucinidae. Comparisons are made between the families, with special emphasis on ecology, life cycle, and connectivity. Chemosynthetic symbioses are a major adaptation to ecosystems and habitats exposed to reducing conditions. However, relatively little is known regarding their diversity and functioning, apart from a few "model species" on which effort has focused over the last 30 yr. In the context of increasing concern about biodiversity and ecosystems, and increasing anthropogenic pressure on oceans, we advocate a better assessment of the diversity of bivalve symbioses in order to evaluate the capacities of these remarkable ecological and evolutionary units to withstand environmental change.

  5. Anodontites trapesialis (LAMARCK, 1819: a bivalve parasite of freshwater fishes / Anodontites trapesialis (LAMARCK, 1819: um bivalve parasito de peixes de água doce

    Directory of Open Access Journals (Sweden)

    Ângela Teresa Silva-Souza

    2008-08-01

    Full Text Available The bivalve mollusk Anodontites trapesialis has been indicated as an alternative source for aquaculture because it is considered a food of good nutritional value with a protein content close to that of fish. Its shells can be utilized as fertilizer and mixed to the food of domestic animals, and the nacre can be used to manufacture buttons and crafts. However, the larvae of A. trapesialis, which are the lasidium type, are obligatory parasites of freshwater fishes, and the introduction of this bivalve in fish farm tanks have caused trouble and losses for producers. Nothing is known, however, about their development in these environments. On the other hand, it should be pointed out that A. trapesialis is on Brazil’s list of species threatened with extinction. This article provides a compilation of information present in the literature, offering a detailed review, with the aim of presenting a general panorama of what is known about Anodontites trapesialis and its larval parasitism of fishes.O molusco bivalve, Anodontites trapesialis, tem sido indicado como fonte alternativa para a aqüicultura, por ser considerado um alimento de bom valor nutricional com um conteúdo protéico próximo ao do pescado. Suas conchas podem ser utilizadas como fertilizantes calcáreos e ser agregadas a alimentos de animais domésticos e o nácar pode ser utilizado para fabricar botões e artesanatos. No entanto, as larvas de A. trapesialis, que são do tipo lasidium, são parasitas obrigatórias de peixes de água doce e a introdução desse bivalve em tanques de piscicultura tem causado transtornos e prejuízos aos produtores. Nada se conhece, porém, sobre o seu desenvolvimento nesses ambientes. Por outro lado, ressalta-se que A. trapesialis consta da lista brasileira de espécies ameaçadas de extinção. No presente artigo são compiladas as informações presentes na literatura, em uma revisão detalhada, com o objetivo de apresentar o panorama geral do

  6. Trophic Dynamics of Filter Feeding Bivalves in the Yangtze Estuarine Intertidal Marsh: Stable Isotope and Fatty Acid Analyses.

    Directory of Open Access Journals (Sweden)

    Sikai Wang

    Full Text Available Benthic bivalves are important links between primary production and consumers, and are essential intermediates in the flow of energy through estuarine systems. However, information on the diet of filter feeding bivalves in estuarine ecosystems is uncertain, as estuarine waters contain particulate matter from a range of sources and as bivalves are opportunistic feeders. We surveyed bivalves at different distances from the creek mouth at the Yangtze estuarine marsh in winter and summer, and analyzed trophic dynamics using stable isotope (SI and fatty acid (FA techniques. Different bivalve species had different spatial distributions in the estuary. Glauconome chinensis mainly occurred in marshes near the creek mouth, while Sinonovacula constricta preferred the creek. Differences were found in the diets of different species. S. constricta consumed more diatoms and bacteria than G. chinensis, while G. chinensis assimilated more macrophyte material. FA markers showed that plants contributed the most (38.86 ± 4.25% to particular organic matter (POM in summer, while diatoms contributed the most (12.68 ± 1.17% during winter. Diatoms made the largest contribution to the diet of S. constricta in both summer (24.73 ± 0.44% and winter (25.51 ± 0.59%, and plants contributed no more than 4%. This inconsistency indicates seasonal changes in food availability and the active feeding habits of the bivalve. Similar FA profiles for S. constricta indicated that the bivalve had a similar diet composition at different sites, while different δ13C results suggested the diet was derived from different carbon sources (C4 plant Spartina alterniflora and C3 plant Phragmites australis and Scirpus mariqueter at different sites. Species-specific and temporal and/or spatial variability in bivalve feeding may affect their ecological functions in intertidal marshes, which should be considered in the study of food webs and material flows in estuarine ecosystems.

  7. Trace elements in the organs and tissues of bivalves in the northwestern Black Sea

    Energy Technology Data Exchange (ETDEWEB)

    Petkevich, T.A.; Gorbyleva, T.P.

    1979-01-01

    An investigation was made of the distribution of 16 trace elements (copper, manganese, iron, aluminum, zinc, barium, strontium, lead, tin, silver, vanadium, nickel, chromium, lithium, titanium and cobalt) in the organs and tissues of bivalves in the northwestern Black Sea and in the Sukhoy and Berezanskiy estuaries. These elements were selected because they are constituents of enzymes, vitamins and other metal-protein complexes, or activate enzymes, and are involved in redox reactions in the transfer of electrons and hydrogen. We investigated mussels (Mytilus galloprovincialis), soft-shell clams (Mya arenaria) and oysters (Ostrea edulis), analyzing the mantle, gills, liver, gonads, adductor muscles, foot and shell, and also in Mya the siphon and its outer epithelial layer, the cuticle. Similar data on Anodonta, a freshwater bivalve of the Dniester estuary, were used for comparison.

  8. Ocean acidification increases cadmium accumulation in marine bivalves: a potential threat to seafood safety.

    Science.gov (United States)

    Shi, Wei; Zhao, Xinguo; Han, Yu; Che, Zhumei; Chai, Xueliang; Liu, Guangxu

    2016-01-21

    To date, the effects of ocean acidification on toxic metals accumulation and the underlying molecular mechanism remains unknown in marine bivalve species. In the present study, the effects of the realistic future ocean pCO2 levels on the cadmium (Cd) accumulation in the gills, mantle and adductor muscles of three bivalve species, Mytilus edulis, Tegillarca granosa, and Meretrix meretrix, were investigated. The results obtained suggested that all species tested accumulated significantly higher Cd (p ocean acidification-induced increase in Cd accumulation may have occurred due to (i) the ocean acidification increased the concentration of Cd and the Cd(2+)/Ca(2+) in the seawater, which in turn increased the Cd influx through Ca channel; (ii) the acidified seawater may have brought about epithelia damage, resulting in easier Cd penetration; and (iii) ocean acidification hampered Cd exclusion.

  9. p53 Superfamily proteins in marine bivalve cancer and stress biology.

    Science.gov (United States)

    Walker, Charles W; Van Beneden, Rebecca J; Muttray, Annette F; Böttger, S Anne; Kelley, Melissa L; Tucker, Abraham E; Thomas, W Kelley

    2011-01-01

    The human p53 tumour suppressor protein is inactivated in many cancers and is also a major player in apoptotic responses to cellular stress. The p53 protein and the two other members of this protein family (p63, p73) are encoded by distinct genes and their functions have been extensively documented for humans and some other vertebrates. The structure and relative expression levels for members of the p53 superfamily have also been reported for most major invertebrate taxa. The functions of homologous proteins have been investigated for only a few invertebrates (specifically, p53 in flies, nematodes and recently a sea anemone). These studies of classical model organisms all suggest that the gene family originally evolved to mediate apoptosis of damaged germ cells or to protect germ cells from genotoxic stress. Here, we have correlated data from a number of molluscan and other invertebrate sequencing projects to provide a framework for understanding p53 signalling pathways in marine bivalve cancer and stress biology. These data suggest that (a) the two identified p53 and p63/73-like proteins in soft shell clam (Mya arenaria), blue mussel (Mytilus edulis) and Northern European squid (Loligo forbesi) have identical core sequences and may be splice variants of a single gene, while some molluscs and most other invertebrates have two or more distinct genes expressing different p53 family members; (b) transcriptional activation domains (TADs) in bivalve p53 and p63/73-like protein sequences are 67-69% conserved with human p53, while those in ecdysozoan, cnidarian, placozoan and choanozoan eukaryotes are ≤33% conserved; (c) the Mdm2 binding site in the transcriptional activation domain is 100% conserved in all sequenced bivalve p53 proteins (e.g. Mya, Mytilus, Crassostrea and Spisula) but is not present in other non-deuterostome invertebrates; (d) an Mdm2 homologue has been cloned for Mytilus trossulus; (e) homologues for both human p53 upstream regulatory and

  10. An ecosystem-based approach and management framework for the integrated evaluation of bivalve aquaculture impacts

    DEFF Research Database (Denmark)

    Cranford, Peter J.; Kamermans, Pauline; Krause, Gesche;

    2012-01-01

    An ecosystem-based approach to bivalve aquaculture management is a strategy for the integration of aquaculture within the wider ecosystem, including human aspects, in such a way that it promotes sustainable development, equity, and resilience of ecosystems. Given the linkage between social...... and ecological systems, marine regulators require an ecosystem-based decision framework that structures and integrates the relationships between these systems and facilitates communication of aquaculture–environment interactions and policy-related developments and decisions. The Drivers-Pressures-State Change...... to assess DPSIR framework components, are reviewed with a focus on the key environmental issues associated with bivalve farming. Indicator selection criteria are provided to facilitate constraining the number of indicators within the management framework. It is recommended that an ecosystem-based approach...

  11. Anticoagulant activity of marine bivalve Donax incarnates Lin, 1758 Collected from Thazhanguda, Southeast coast of India

    Institute of Scientific and Technical Information of China (English)

    P. Bharathirajan

    2012-01-01

    Objective: Molluscs are highly delicious seafood and they are also very good source for biomedically imported products. Among the molluscs some have pronounced pharmacological activities or other properties which are useful in biomedical area. Methods: In the present study GAGs was isolated from the bivalve such as Donax incarnates. Results: The isolated GAGs were quantified in crude samples and they were estimated as 6.84 gm/kg crude GAGs in Donax incarnates. The bivalve showed the anticoagulant activity of the crude samples 124.53 USP units/mg in Donax incarnates. FTIR analysis reveals the presence of anticoagulant substance signals at different ranges. Conclusions: The determined in this research show that gastropod Donax incarnates tissue is value medicinal due to high quality of anticoagulant compounds.

  12. Contamination of raw bivalve molluscs available in Poland between 2009 and 2013 with marine biotoxins

    Directory of Open Access Journals (Sweden)

    Michalski Mirosław

    2016-12-01

    Full Text Available Introduction: Growing consumption of shellfish is associated with an increased risk of food poisoning. The study was carried out on live bivalve molluscs available on the Polish market between 2009 and 2013. Material and Methods: ELISA was used for the determination of the following marine biotoxins: paralytic shellfish poison (PSP, amnaesic shellfish poison (ASP, and diarrhoeic shellfish poison (DSP. The molluscs, of which seven species were examined, were obtained from wholesale companies and markets. Results: Marine biotoxins were detected below the permitted levels in 67.6% of the samples. The maximum amounts of PSP and ASP biotoxins were found in great scallops (532.6 μg/kg and 1.0 mg/kg respectively and the peak for DSP was in blue mussels (107 μg/kg. Conclusion: The analysis of toxicological status of raw bivalve molluscs available on the market in Poland indicates that they are safe for consumers.

  13. Paleoenvironmental and paleoclimatic significance of freshwater bivalves in the Upper Jurassic Morrison Formation, Western Interior, USA

    Science.gov (United States)

    Good, Steven C.

    2004-05-01

    Freshwater unionid bivalves are spatially and temporally distributed throughout the Morrison depositional basin, and locally dominate the biomass of many aquatic depositional environments. Two bivalve assemblages are identified. Within-channel assemblages are death assemblages that have been transported and may represent mixed assemblages from multiple communities. These assemblages are predominately disarticulated, in current stable orientations, and composed of higher stream velocity ecophenotypes (medium size, lanceolate form, and very thick shells). The floodplain-pond assemblages are disturbed neighborhood assemblages in the mudstones inhabited during life. The bivalves are predominately articulated, variable in size, and composed of low stream velocity ecophenotypes (large maximum sizes, ovate shell shapes, and thinner shells). The glochidial parasitic larval stage of unionid bivalves provides an effective means of dispersing species throughout drainage basins. These larvae attach to fish and are carried through the fluvial drainage where the larvae detach and establish new bivalve communities. Preliminary paleobiogeographic analyses are drawn at the genus level because of the need to reevaluate bivalve species of the Morrison. Unio spp. and Vetulonaia spp. are widespread throughout the Morrison depositional basin, but Hadrodon spp. are restricted to the eastern portion of the Colorado Plateau during Salt Wash Member deposition, suggesting that Salt Wash drainage was isolated from other contemporaneous regions of the basin. Bivalves from five localities in the Morrison Formation were thin-sectioned for growth band analysis. Growth bands of modern unionid bivalves are produced when the valves are forced to close. Closure can produce annual growth bands in response to seasonal variation, such as temperature-induced hibernation, or precipitation-induced aestivation or turbidity. Pseudoannual growth bands form from non-cyclical events such as predation attacks or

  14. Studies on filtration rate in four species of suspension feeding bivalves

    Institute of Scientific and Technical Information of China (English)

    林元烧; 罗文新; 曹文清; 郭东晖; 郑爱榕; 黄长江

    2002-01-01

    The filtration rates of four kinds of bivalves that were cultivated dominantly around Xiamen sea area were measured by using a laboratory flowing system. The experimental results were shown below: (1) Filtration rates were measured in the range of 54~74.8 ml/ (g@min) among the four bivalves, sequencing descently Saccostrea cucullata > Sinonovacula constricta > Mytilus viridis > Ruditapes philippinarum. (2) The relationship between filtration rates on individual size showed a negative exponential function (FR = aWb, FR' = aWb-1), with b - 1 = - 0.435 6 and - 0.392. (3) Filtration rates on Skeletonema costatum were much higher than on Alexandrium tamarensis and Scrippsilla trochoidea inS. Cucullata and R. Philippinarum. (4) FR'on algal densities was also shown a negative function(FR' = aDb-1), with b-1 =-0.143 and-0.215 2 in S.cucullata and R.philippinarum, respectively.

  15. [Isolation of enteropathogenic Vibrio in bivalves and mud from the Nicoya Gulf, Costa Rica].

    Science.gov (United States)

    García Cortés, V; Antillón, F

    1990-11-01

    The presence of enteropathogenic Vibrio was evaluated in 36 sediment samples and 41 bivalve samples obtained from 3 collecting sites in the Golfo de Nicoya, Costa Rica. Isolation methods for halophilic and non halophilic Vibrio were used. The biochemical profiles of the strains obtained revealed the presence of the following isolates: 224 Vibrio parahaemolyticus, 3 V. furnissii, 1 V. damsela and 3 V. fluvialis. V. cholerae was not isolated, due principally to the use of TCBS agar.

  16. Bivalves and gastropods from the middle Campanian Anacacho limestone, South Central Texas

    Science.gov (United States)

    Elder, W.P.

    1996-01-01

    The Anacacho Limestone was deposited during the Campanian and represents two depositional intervals, one of early Campanian and one of middle Campanian age. These two intervals correspond to periods of major eustatic sea level rise. This study focuses on the molluscan paleontology of the middle Campanian interval in the eastern part of the Anacacho exposure belt in Medina County, Texas. Molluscan assemblages in this area are indicative of inner to mid-shelf environments. No significant reef components are present. These eastern Anacacho deposits are interpreted to represent more offshore, deeper water environments than those to the southwest, where reef and lagoonal deposits have been reported. Analysis of the macrofossil components from these eastern localities has expanded the number of invertebrate species known from the Anacacho Limestone by nearly three-fold. This increase in diversity, based on a small amount of new work, suggests that many more taxa are yet to be identified, particularly in the western part of the exposure belt in Uvalde and Kinney Counties. This paper documents the bivalve and gastropod fauna, discussing and illustrating 24 bivalve taxa and 11 gastropod species. Two new bivalve species are named, Panopea anacachoensis new species and Spondylus siccus new species, and two potentially new gastropod species are identified but not named herein due to inadequate material. This paper expands the distribution of many eastern Gulf Coast and Atlantic Coast taxa westward into Texas and shows strong ties between the Anacacho fauna and that of the Campanian Tar Heel and Bladen Formations of the Black Creek Group in North Carolina. The taxonomic ties between these two areas probably reflect the thorough documentation of the North Carolina fauna, which is the best documented Campanian bivalve fauna in the Gulf or Atlantic Coast regions.

  17. Ethno-malacological knowledge of bivalve mollusks gathering in Acupe mangrove, Santo Amaro, Bahia

    Directory of Open Access Journals (Sweden)

    Francisco José Bezerra Souto

    2009-12-01

    Full Text Available The mangrove is a highly productive ecosystem that carries out important ecological functions and that historically it has been used for the subsistence and income of countless craft fishing communities. In the mangroves of Todos os Santos Bay, including those of the District of Acupe (Santo Amaro – Bahia State, the bivalve mollusks (shellfish are among the most important resources, and their gathering is known as “mariscagem”. This work aims to characterize the knowledge of the local female shellfish gatherers regarding the biology and ecology of bivalve shellfish. Semi-structured interviews were used with local shellfish women (N=54 involving ethnotaxonomy, trophic ecology, hydrodynamics, fenology and ethnocronology. Etic-emic analisys of the data was chosen in order to compare the information obtained in the field to that from the academic literature. The results demonstrated that the shellfish women of Acupe have a significant knowledge of bivalve shellfish, in addition to aspects related to the dynamics of local mangroves, that is sometimes compatible with academic knowledge.

  18. Predicting growth and mortality of bivalve larvae using gene expression and supervised machine learning.

    Science.gov (United States)

    Bassim, Sleiman; Chapman, Robert W; Tanguy, Arnaud; Moraga, Dario; Tremblay, Rejean

    2015-12-01

    It is commonly known that the nature of the diet has diverse consequences on larval performance and longevity, however it is still unclear which genes have critical impacts on bivalve development and which pathways are of particular importance in their vulnerability or resistance. First we show that a diet deficient in essential fatty acid (EFA) produces higher larval mortality rates, a reduced shell growth, and lower postlarval performance, all of which are positively correlated with a decline in arachidonic and eicosapentaenoic acids levels, two EFAs known as eicosanoid precursors. Eicosanoids affect the cell inflammatory reactions and are synthesized from long-chain EFAs. Second, we show for the first time that a deficiency in eicosanoid precursors is associated with a network of 29 genes. Their differential regulation can lead to slower growth and higher mortality of Mytilus edulis larvae. Some of these genes are specific to bivalves and others are implicated at the same time in lipid metabolism and defense. Several genes are expressed only during pre-metamorphosis where they are essential for muscle or neurone development and biomineralization, but only in stress-induced larvae. Finally, we discuss how our networks of differentially expressed genes might dynamically alter the development of marine bivalves, especially under dietary influence.

  19. Lincoln Park shoreline erosion control project: Monitoring for surface substrate, infaunal bivalves and eelgrass, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Antrim, L.D.; Thom, R.M.; Gardiner, W.W. [Battelle/Marine Sciences Lab., Sequim, WA (United States)

    1993-09-01

    In 1988, the US Army Corps of Engineers and the City of Seattle placed material on the upper beach at Lincoln Park, in West Seattle, Washington. The fill served to mitigate shoreline erosion that had caused undercutting and collapse of the seawall in several places. A series of pre- and post-construction studies have been conducted to assess the impacts to marine biota of fill placement and movement of surface substrate. This study was designed to monitor infaunal bivalves and eelgrass from intertidal areas in and adjacent to the area of original fill placement. Findings from this survey were compared to previous survey results to determine (1) if recruitment of infaunal bivalves to the fill area has occurred, (2) if infaunal bivalve densities outside the fill area are stable, and (3) if eelgrass distribution and abundance have remained stable along the adjacent shoreline. To maximize comparability of findings from this survey with previous studies, sampling techniques, transects, and tidal elevations were consistent with previous studies at this site.

  20. Availability of pearl producing marine bivalves in south-eastern coast of Bangladesh and culture potentialities

    Directory of Open Access Journals (Sweden)

    Md Ataur Rahman

    2015-12-01

    Full Text Available The present study was conducted during September 2014 to July 2015 to identify the pearl bearing bivalves in south-eastern coast of Bangladesh and culture potentialities of marine oyster in captivity based on field investigation. A total of 7 pearl bearing bivalve species were identified in the coast with a salinity of 18-34 ppt, pH 8.1-8.3 and water depth ranged 0.2-2.0 meter in their habitat. From the collected bivalves, most abundant oyster species windowpane oyster, Placuna placenta (Linnaeus, 1758 was reared in fiber glass tanks with seawater for a period of 6 months. During rearing highest survival rate of 88% was observed in T1 with sandy and gravel substratum and lowest survival rate of 78% was found in T2 with muddy substratum. Average temperature and salinity were varied between 24 °C-25 °C and 21-26 ppt respectively. From the reared oyster, highest 54 nos. small pearls in the month of April and lowest 7 pearls in December from a single P. placenta were obtained. The study proved that pearls can be obtained from the marine oysters in captivity in Bangladesh, and this offers large scale culture potentialities in our coast.

  1. Trace element ratios in bivalve shells as records of environmental conditions

    Science.gov (United States)

    Tynan, S.; Opdyke, B.; Welch, S.; Beavis, S.

    2007-12-01

    Stable isotope and trace element data from the carbonate of both marine and freshwater bivalves are proving to be useful tools in studies of palaeoclimate and environmental change. However, much of the work already done has shown that the trace element ratios in bivalve shells exhibit a complex relationship with the ambient environment and caution must be exercised when attempting to use them as environmental proxies. This work examines the feasibility of using the trace element ratios Mg/Ca, Sr/Ca, Ba/Ca and Mn/Ca of the shells of a number of different species of bivalves as records of the temperature and salinity of their ambient aquatic environment. The species analysed were the estuarine oysters Saccostrea glomerata, Ostrea angasi, and Crassostrea gigas, an estuarine mussel, Mytilus galloprovincialis, and the freshwater mussel Velesunio ambiguus. The estuarine shells were taken from monitoring experiments conducted over a period of 12 months at two different field sites. Freshwater shells were collected wild, from locations close to water monitoring stations. Preliminary results show distinct variations in the Mg/Ca of O. angasi shells with an apparent seasonal pattern. V. ambiguus shells show clear patterns in Mn/Ca, linked to environmental variations.

  2. Observations on shell growth and morphology of the bivalve Ruditapes philippinarum

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The bivalve Ruditapes philippinarum is not only one of the main mollusc species in the west Pacific Ocean, but also one of the main species for aquaculture in China. Knowledge of growth of the R. philippinarum shell will improve our understanding of the shell as an environmental archive. It is also useful for the aquaculture of R. philippinarum. In this research, a hanging box culture method was introduced in the culture of R. philippinarum. The bivalves were cultured for 126 days, from March 31 to August 3, 2002. The average growth rates of shell width, height, and thickness were 0.069, 0.046, and 0.032 mm/d, respectively. The mean increase of average individual wet mass was 0.028 g/d. The largest growth rates of both shell and average individual wet mass occurred in June, indicating that water temperature and bivalve reproduction were 2 important factors. The shell morphology underwent significant changes with shell growth. The ratio of height to thickness (value of B/C) shifted 1.58 in the first 60 days to 1.54 in the last 30 days, which was resulted from the change in major shell growth direction. Periodic changes in the B/C ratio led to corrugated shell form, which could be used to determine the age of the shell.

  3. Explosive demographic expansion by dreissenid bivalves as a possible result of astronomical forcing

    Directory of Open Access Journals (Sweden)

    M. Harzhauser

    2013-07-01

    Full Text Available Human induced range expansions of invasive dreissenid bivalves are of great concern. However, the underlying biological processes are only poorly understood, partly due to the lack of information on natural expansion events. Here we use the extinct bivalve species Sinucongeria primiformis as a model organism for testing natural (i.e. non-Anthropocene blooms of dreissenid species in a lacustrine system of Lake Pannon during the Tortonian (~10.5 Myr; Late Miocene. 600 samples from a consecutive core were evaluated for the relative abundance of this pavement-forming mollusc, which cover about 8 millennia of Late Miocene time with a decadal resolution. Our data indicate that the settlement by bivalves in the offshore environment was limited mainly by bottom water oxygenation, which follows predictable and repetitive patterns through time. These population fluctuations might be related to solar cycles: successful dreissenid settlement is re-occurring in a frequency known as the lower and upper Gleissberg cycles with a 50–80 and 90–120 yr period. These cycles appear to control regional wind patterns, which are directly linked to water mixing of the lake. This is modulated by the even more prominent 500 yr cycle, which seems to be the most important pacemaker for Lake Pannon hydrology.

  4. Chemosynthetic bacteria found in bivalve species from mud volcanoes of the Gulf of Cadiz.

    Science.gov (United States)

    Rodrigues, Clara F; Webster, Gordon; Cunha, Marina R; Duperron, Sébastien; Weightman, Andrew J

    2010-09-01

    As in other cold seeps, the dominant bivalves in mud volcanoes (MV) from the Gulf of Cadiz are macrofauna belonging to the families Solemyidae (Acharax sp., Petrasma sp.), Lucinidae (Lucinoma sp.), Thyasiridae (Thyasira vulcolutre) and Mytilidae (Bathymodiolus mauritanicus). The delta(13)C values measured in solemyid, lucinid and thyasirid specimens support the hypothesis of thiotrophic nutrition, whereas isotopic signatures of B. mauritanicus suggest methanotrophic nutrition. The indication by stable isotope analysis that chemosynthetic bacteria make a substantial contribution to the nutrition of the bivalves led us to investigate their associated bacteria and their phylogenetic relationships based on comparative 16S rRNA gene sequence analysis. PCR-denaturing gradient gel electrophoresis analysis and cloning of bacterial 16S rRNA-encoding genes confirmed the presence of sulfide-oxidizing symbionts within gill tissues of many of the studied specimens. Phylogenetic analysis of bacterial 16S rRNA gene sequences demonstrated that most bacteria were related to known sulfide-oxidizing endosymbionts found in other deep-sea chemosynthetic environments, with the co-occurrence of methane-oxidizing symbionts in Bathymodiolus specimens. This study confirms the presence of several chemosynthetic bivalves in the Gulf of Cadiz and further highlights the importance of sulfide- and methane-oxidizing symbionts in the trophic ecology of macrobenthic communities in MV.

  5. Evaluation of γ-radiation-induced DNA damage in two species of bivalves and their relative sensitivity using comet assay.

    Science.gov (United States)

    Praveen Kumar, M K; Shyama, S K; Sonaye, B S; Naik, U Roshini; Kadam, S B; Bipin, P D; D'costa, A; Chaubey, R C

    2014-05-01

    Ionizing radiation is known to induce genetic damage in diverse groups of organisms. Under accidental situations, large quantities of radioactive elements get released into the environment and radiation emitted from these radionuclides may adversely affect both the man and the non-human biota. The present study is aimed (a) to know the genotoxic effect of gamma radiation on aquatic fauna employing two species of selected bivalves, (b) to evaluate the possible use of 'Comet assay' for detecting genetic damage in haemocytes of bivalves as a biomarker for environmental biomonitoring and also (c) to compare the relative sensitivity of two species of bivalves viz. Paphia malabarica and Meretrix casta to gamma radiation. The comet assays was optimized and validated using different concentrations (18, 32 and 56 mg/L) of ethyl methanesulfonate (EMS), a direct-acting reference genotoxic agent, to which the bivalves were exposed for various times (24, 48 and 72 h). Bivalves were irradiated (single acute exposure) with 5 different doses (viz. 2, 4, 6, 8 and 10 Gy) of gamma radiation and their genotoxic effects on the haemocytes were studied using the comet assay. Haemolymph was collected from the adductor muscle at 24, 48 and 72 h of both EMS-exposed and irradiated bivalves and comet assay was carried out using standard protocol. A significant increase in DNA damage was observed as indicated by an increase in % tail DNA damage at different concentrations of EMS and all the doses of gamma radiation as compared to controls in both bivalve species. This showed a dose-dependent increase of genetic damage induced in bivalves by EMS as well as gamma radiation. Further, the highest DNA damage was observed at 24h. The damage gradually decreased with time, i.e. was smaller at 48 and 72 h than at 24h post irradiation in both species of bivalves. This may indicate repair of the damaged DNA and/or loss of heavily damaged cells as the post irradiation time advanced. The present study

  6. Museum Preserved Bivalves as Indicators of Long-term Trends in Methylmercury Concentrations

    Science.gov (United States)

    Luengen, A. C.; Foslund, H. M.; Greenfield, B. K.

    2015-12-01

    Despite the many efforts to reduce mercury concentrations in the environment, there are relatively few datasets on long-term trends in mercury in biota, especially for the bioavailable form, methylmercury (MeHg). This study used museum preserved bivalves (stored in ethanol) to look at MeHg trends in the Asian date mussel Musculista senhousia and the Asian clam Potamocorbula amurensis, collected from San Francisco Bay, California between 1975 and 2012. For each sampling date, 4 to 15 individuals were obtained from museum collections (N = 156 total specimens), freeze-dried, weighed, homogenized, digested, and individually analyzed for MeHg using trace metal clean techniques. The bivalves were also analyzed for δ13C and δ15N to look for changes in food web structure. P. amurensis specimens were only available from 1988 to 2012, and an increase in MeHg was observed during that time. In contrast, M. senhousia specimens were available for the entire 37 year period and exhibited a significant decline in MeHg in the southern reach of the estuary (South Bay). The median MeHg concentration in M. senhousia was highest at 239 ng/g dw in October 1975. That year was the last year of operations for the New Almaden Mercury Mining District, which drained into South Bay. By the 1990s, MeHg concentrations in M. senhousia dropped significantly to a median of 37 ng/g dw. Isotopic δ15N values did not support a hypothesis of reduced trophic position causing the MeHg decline. Over the study duration, δ15N increased in M. senhousia, which we attributed to a baseline shift. We also observed a decline in δ13C since 2000, which may represent a shift in bivalve carbon towards greater utilization of planktonic sources. To validate the use of museum specimens, we ran a preservation study, where we collected fresh bivalves, fixed them in ethanol or formalin, and then transferred them to ethanol for long-term storage. Although MeHg concentrations increased after 1 week, they stabilized over

  7. Adaptive morphologies and guild structure in a high-diversity bivalve fauna from an early Campanian rocky shore, Ivö Klack (Sweden)

    DEFF Research Database (Denmark)

    Sørensen, Anne Mehlin; Surlyk, Finn; Jagt, John W. M.

    2012-01-01

    The bivalve fauna from a late early Campanian rocky shore at Ivö Klack (southern Sweden), comprises just over sixty species, a very high diversity in comparison to other Late Cretaceous and modern rocky shore bivalve assemblages. This high diversity is here considered to represent a reliable census...... adjacent environments. It includes some of the most northerly known, very small rudistid bivalves, in addition to the oldest known occurrences of Mytilus and Barbatia in association with rocky shores. Bivalves constituted the most important invertebrate group inhabiting the late early Campanian rocky shore...

  8. Burrowing criteria and burrowing mode adjustment in bivalves to varying geoenvironmental conditions in intertidal flats and beaches.

    Directory of Open Access Journals (Sweden)

    Shinji Sassa

    Full Text Available The response of bivalves to their abiotic environment has been widely studied in relation to hydroenvironmental conditions, sediment types and sediment grain sizes. However, the possible role of varying geoenvironmental conditions in their habitats remains poorly understood. Here, we show that the hardness of the surficial intertidal sediments varies by a factor of 20-50 due to suction development and suction-induced void state changes in the essentially saturated states of intertidal flats and beaches. We investigated the response of two species of bivalves, Ruditapes philippinarum and Donax semigranosus, in the laboratory by simulating such prevailing geoenvironmental conditions in the field. The experimental results demonstrate that the bivalve responses depended strongly on the varying geoenvironmental conditions. Notably, both bivalves consistently shifted their burrowing modes, reducing the burrowing angle and burial depth, in response to increasing hardness, to compensate for the excessive energy required for burrowing, as explained by a proposed conceptual model. This burrowing mode adjustment was accompanied by two burrowing criteria below or above which the bivalves accomplished vertical burrowing or failed to burrow, respectively. The suitable and fatal conditions differed markedly with species and shell lengths. The acute sensitivities of the observed bivalve responses to geoenvironmental changes revealed two distinctive mechanisms accounting for the adult-juvenile spatial distributions of Ruditapes philippinarum and the behavioral adaptation to a rapidly changing geoenvironment of Donax semigranosus. The present results may provide a rational basis by which to understand the ensuing, and to predict future, bivalve responses to geoenvironmental changes in intertidal zones.

  9. Permian bivalves of the Taciba Formation, Itararé Group, Paraná Basin, and their biostratigraphic significance

    Directory of Open Access Journals (Sweden)

    Marcello Guimarães Simões

    2012-04-01

    Full Text Available A small and poorly diversified bivalve fauna from Taciba Formation, Itararé Group, Paraná Basin (State of Santa Catarina,Mafra Municipality, is described in this paper for the first time, based on new findings. The fauna is recorded in a 30 cmthick interval of fine sandstone locally at the top of Taciba Formation, in the Butiá quarry. The studied fossil-bearing sandstonebed is a marine intercalation recording a brief eustatic rise in sea-level, probably following glacier retreat and climateamelioration at the end of a broad glacial scenario. The fauna is mainly dominated by productid brachiopods, which are notdescribed here, and rare mollusk shells (bivalves and gastropods. Two bivalve species were identified: Myonia argentinensis(Harrington, 1955, and Aviculopecten multiscalptus (Thomas, 1928. The presence of Myonia argentinensis is noteworthysince this species is also present in the Baitaca assemblage found in marine siltstones (Baitaca assemblage of theRio do Sul Formation, cropping out at the Teixeira Soares region, Paraná State. This species is also recorded in the bivalvefauna from the Bonete Formation, Pillahinco Group, Sauce Grande Basin, Buenos Aires Province, in Argentina. Hence, themarine bivalves of the Taciba Formation are associated with the transgressive event that characterizes the Eurydesma fauna,indicating a Late Asselian-Sakmarian age for the bivalve fauna. Presence of the Myonia argentinensis megadesmid speciesreinforces the Gondwanic nature of the studied fauna.

  10. Behavior of Zn, Cu, Pb and Cd in biota of Yangtze Estuary

    Institute of Scientific and Technical Information of China (English)

    陆健健; 唐亚文; 唐亚文; 周开亚; 叶属峰; 孙平跃

    2001-01-01

    The contents of zinc, copper, lead and cadmium were measured in the dominant species (plants: Scripus triquetor and Phrgrmites australis, macrobenthos: llyoplax deschampsin, Helice tridens tientsinensis, Bullacta exarata and Corbicula fluminea, and migrating waders: Calidris ruficollis and C. alpina) of the ecosystem of Yangtze Estuary, China, from 1995-1998. Results show that:

  11. Lower Mississippi River Environmental Program. Report 12. An Ecological Investigation of the Baleshed Landing-Ben Lomond and Ajax Bar Dike Systems in the Lower Mississippi River, River Miles 481 to 494 AHP

    Science.gov (United States)

    1988-04-01

    Plecoptera PS,G Copepoda 24 121 S,F Cladocera Daphnidae Daphnia sp. F Arachnida p Castropoda 1 SSC Pelecypoda 73 F Corbiculidae Corbicula fluminea 49...Hemiptera 24 P Plecoptera 24 P,SH,G Copepoda 121 S,F Cladocera Daphnidae Dahi sp. 24 F Arachnida 24 P Gastropoda 49 SSC Pelecypoda 121 F Corbiculidae

  12. Distribution of persistent toxic substances in benthic bivalves from the inshore areas of the Yellow Sea.

    Science.gov (United States)

    Liu, Wen X; Hu, Jing; Chen, Jiang L; Fan, Yong S; Xing, Baoshan; Tao, Shu

    2008-01-01

    A baseline survey of trace metals and organic pollutants in bivalves from the coastal areas of the Yellow Sea (China) showed the the concentrations of Cd and Pb in the bivalves from more than 85 and 73%, respectively, of the total sites (30 sites in all) exceeded the low limits of the national quality standards for marine organisms. At three sites, the contents of Cd in three species were even higher than the median limit, and a similar case with Pb occurred at another site. The tissue concentrations of As at four sites and of Hg at one site were above the low and the median limits, respectively, of the quality standards. At 43% of all sites, the levels of petroleum hydrocarbons were higher than the low limit of the quality standards, and the tissue concentrations at two sites even went beyond the median limit at one site and the high limit at the other. The concentrations of phthalate esters and polycyclic aromatic hydrocarbons (PAHs) in the collected bivalves were not high, as shown by peak values of 305 and 302 ng/g, respectively. The contents of polychlorinated biphenyls for all the species were much lower than the low limit of the quality standards. The compositional properties and isomeric ratios of PAHs indicated various pyrolytic procedures as the dominant origins. The sites with higher tissue contents of DDT and its metabolites (DDTs) over the low or the median quality limit were located mainly in the South Yellow Sea. The fractions and specific ratios of DDTs suggested that new inputs of DDT existed at two sites in the North Yellow Sea, and the potential sources involved technical DDT, technical dicofol, and their mixture.

  13. P-glycoprotein and its inducible expression in three bivalve species after exposure to Prorocentrum lima.

    Science.gov (United States)

    Huang, Lu; Liu, Su-Li; Zheng, Jian-Wei; Li, Hong-Ye; Liu, Jie-Sheng; Yang, Wei-Dong

    2015-12-01

    P-glycoprotein (P-gp or ABCB1) belongs to the family of ATP-binding cassette (ABC) transporters responsible for multixenobiotic resistance (MXR) in aquatic organisms. To provide more information of P-gp in shellfish, in this study, complete cDNA of P-gp in three bivalve species including Ruditapes philippinarum, Scapharca subcrenata and Tegillarca granosa were cloned and its expressions in gill, digestive gland, adductor muscle and mantle of the three bivalves were detected after exposure to Prorocentrum lima, a toxogenic dinoflagellate. The complete sequences of R. philippinarum, S. subcrenata and T. granosa P-gp showed high homology with MDR/P-gp/ABCB proteins from other species, having a typical sequence organization as full transporters from the ABCB family. Phylogenetic analyses revealed that the amino acid sequences of P-gp from S. subcrenata and T. granosa had a closest relationship, forming an independent branch, then grouping into the other branch with Mytilus californianus, Mytilus galloprovincialis and Crassostrea gigas. However, P-gp sequences from R. philippinarum were more similar to the homologs from the more distantly related Aplysia californica than to homologs from S. subcrenata and T. granosa, suggesting that bivalves P-gp might have different paralogs. P-glycoprotein expressed in all detected tissues but there were large differences between them. After exposure to P. lima, the expression of P-gp changed in the four tissues in varying degrees within the same species and between different species, but the changes in mRNA and protein level were not always synchronous.

  14. Diversity of Gastropods and Bivalves in mangrove ecosystem rehabilitation areas in Aceh Besar and Banda Aceh districts, Indonesia

    Directory of Open Access Journals (Sweden)

    Dewiyanti Irma

    2012-06-01

    Full Text Available Abstract. This study was conducted in mangrove rehabilitation area on May to November 2011. The objective of the present study was toevaluate the diversity of Gastropods and Bivalves based on the different level of vegetation age of mangrove. Sampling were conducted on 1x 1 m2 of square transects. We recorded 14 species of Gastropods and 5 species of Bivalves with abundance of 371 individuals/m2 and 28 individuals/m2, respectively. The highest abundance of Gastropod was found on 4 years vegetation age on Cerithidae cingulata (150 individuals/m2, while the highest abundance of Bivalves was found on 3 years vegetation age on Pedalion isognomum (8 individuals/m2. In conclusion,the condition of community structure post tsunami was unstable.

  15. New records of recently described chemosymbiotic bivalves for mud volcanoes within the European waters (Gulf of Cádiz

    Directory of Open Access Journals (Sweden)

    J.L. RUEDA

    2013-01-01

    Full Text Available Chemosymbiotic bivalves are important members of cold seep communities and information on their distribution in theEuropean waters is still quite scarce. This study reports the presence of living populations and shell remains of some recently described bivalves such as Lucinoma asapheus, Solemya elarraichensis and Acharax gadirae as well as Bathymodiolus sp. in the mud volcanoes of the Spanish Atlantic waters. Living populations of these species were thus far only found in Anastasya, Aveiro and Almazán mud volcanoes, together with other chemosymbiotic metazoa (Siboglinum spp., suggesting the presence of moderate seepage activity. In other mud volcanoes (Albolote, Gazul, the benthic communities are dominated by sessile filter feeders on authigenic carbonates (chimneys, slabs and only the shell remains of some chemosymbiotic bivalves were found, indicating earlier or very low seepage conditions. The present study elaborates on the known distribution of L. asapheus and S. elarraichensis to the European waters of the Gulf of Cádiz.

  16. Evaluation of γ-radiation-induced DNA damage in two species of bivalves and their relative sensitivity using comet assay

    Energy Technology Data Exchange (ETDEWEB)

    Praveen Kumar, M.K., E-mail: here.praveen@gmail.com [Department of Zoology, Goa University, Goa 403206 (India); Shyama, S.K., E-mail: skshyama@gmail.com [Department of Zoology, Goa University, Goa 403206 (India); Sonaye, B.S. [Department of Radiation Oncology, Goa Medical College, Goa (India); Naik, U Roshini; Kadam, S.B.; Bipin, P.D.; D’costa, A. [Department of Zoology, Goa University, Goa 403206 (India); Chaubey, R.C. [Radiation Biology and Health Science Division, Bhabha Atomic Research Centre, Mumbai (India)

    2014-05-01

    Highlights: • Possible genotoxic effect of accidental exposure of aquatic fauna to γ radiation. • Relative sensitivity of bivalves to γ radiation is also analyzed using comet assay. • γ radiation induced significant genetic damage in both the species of bivalves. • P. malabarica and M. casta exhibited a similar level of sensitivity to γ radiation. • Comet assay may be used as a biomarker for the environmental biomonitoring. - Abstract: Ionizing radiation is known to induce genetic damage in diverse groups of organisms. Under accidental situations, large quantities of radioactive elements get released into the environment and radiation emitted from these radionuclides may adversely affect both the man and the non-human biota. The present study is aimed (a) to know the genotoxic effect of gamma radiation on aquatic fauna employing two species of selected bivalves, (b) to evaluate the possible use of ‘Comet assay’ for detecting genetic damage in haemocytes of bivalves as a biomarker for environmental biomonitoring and also (c) to compare the relative sensitivity of two species of bivalves viz. Paphia malabarica and Meretrix casta to gamma radiation. The comet assays was optimized and validated using different concentrations (18, 32 and 56 mg/L) of ethyl methanesulfonate (EMS), a direct-acting reference genotoxic agent, to which the bivalves were exposed for various times (24, 48 and 72 h). Bivalves were irradiated (single acute exposure) with 5 different doses (viz. 2, 4, 6, 8 and 10 Gy) of gamma radiation and their genotoxic effects on the haemocytes were studied using the comet assay. Haemolymph was collected from the adductor muscle at 24, 48 and 72 h of both EMS-exposed and irradiated bivalves and comet assay was carried out using standard protocol. A significant increase in DNA damage was observed as indicated by an increase in % tail DNA damage at different concentrations of EMS and all the doses of gamma radiation as compared to controls in

  17. Detection and identification of tdh- and trh-positive Vibrio parahaemolyticus strains from four species of cultured bivalve molluscs on the Spanish Mediterranean Coast.

    Science.gov (United States)

    Roque, Ana; Lopez-Joven, Carmen; Lacuesta, Beatriz; Elandaloussi, Laurence; Wagley, Sariqa; Furones, M Dolores; Ruiz-Zarzuela, Imanol; de Blas, Ignacio; Rangdale, Rachel; Gomez-Gil, Bruno

    2009-12-01

    Presented here is the first report describing the detection of potentially diarrheal Vibrio parahaemolyticus strains isolated from cultured bivalves on the Mediterranean coast, providing data on the presence of both tdh- and trh-positive isolates. Potentially diarrheal V. parahaemolyticus strains were isolated from four species of bivalves collected from both bays of the Ebro delta, Spain.

  18. Investigating the impact of drilling mud and its major components on bivalve species of Georges Bank

    Energy Technology Data Exchange (ETDEWEB)

    1978-11-01

    The objective of this program has been to measure the response of commercially important marine bivalve molluscs to low levels of drilling muds. Because these materials are composed of several major components whose proportions vary between wells and with depth for a single well, the approach of this study has been to test the major components individually and then to test a representative synthetic mud and finally a used drilling mud from an offshore platform. In all but one of these tests the target organism has been the sea scallop, Placopecten magellanicus.

  19. Host-parasite interactions: Marine bivalve molluscs and protozoan parasites, Perkinsus species.

    Science.gov (United States)

    Soudant, Philippe; E Chu, Fu-Lin; Volety, Aswani

    2013-10-01

    This review assesses and examines the work conducted to date concerning host and parasite interactions between marine bivalve molluscs and protozoan parasites, belonging to Perkinsus species. The review focuses on two well-studied host-parasite interaction models: the two clam species, Ruditapes philippinarum and R. decussatus, and the parasite Perkinsus olseni, and the eastern oyster, Crassostrea virginica, and the parasite Perkinsus marinus. Cellular and humoral defense responses of the host in combating parasitic infection, the mechanisms (e.g., antioxidant enzymes, extracellular products) employed by the parasite in evading host defenses as well as the role of environmental factors in modulating the host-parasite interactions are described.

  20. Estimation of food limitation of bivalve larvae in coastal waters of north-western Europe

    DEFF Research Database (Denmark)

    Bos, O.G.; Hendriks, I.E.; Strasser, M.;

    2006-01-01

    Marine invertebrate recruitment may be affected by food limitation during the pelagic larval life stages. In the present study, field data on abundance of bivalve larvae along with their prey (small phytoplankton) were examined to see whether they were consistent with predictions made by an energ...... assimilation rate averaged 7-26% of the maximum assimilation rate. Under the assumptions made for the present study, it is suggested that growth of larvae in north-west European waters is often food-limited. (c) 2005 Elsevier B.V. All rights reserved...

  1. Bivalves and Gastropods of the Gulf of Tehuantepec, Mexico: A Checklist of Species with Notes on Their Habitat and Local Distribution

    Directory of Open Access Journals (Sweden)

    Eduardo Ríos-Jara

    2009-01-01

    Full Text Available The taxonomic composition of 160 species of bivalves and gastropods recorded in the Gulf of Tehuantepec is presented with information on their habitat and distribution along 10 different localities of the shoreline and 42 stations of the continental shelf. The species were on sandy and rocky beaches, coastal lagoons, estuaries, mangroves, rocky breakwaters of ports, and shallow subtidal areas (14–47 m depth. A total of 78 bivalve species and 82 gastropod species were recorded. Most of these were associated with sandy and rocky beaches and breakwaters of ports. The estuaries host 30 species and the coastal lagoons only two. In the shallow subtidal there were 18 gastropod species and 40 bivalve species representing 36.3% of all. This study adds 24 bivalve species and 29 gastropod species not recorded in previous studies for a total count of 213 species (102 bivalves and 111 gastropods for Gulf of Tehuantepec.

  2. Predation on exotic zebra mussels by native fishes: Effects on predator and prey

    Science.gov (United States)

    Magoulick, D.D.; Lewis, L.C.

    2002-01-01

    1. Exotic zebra mussels, Dreissena polymorpha, occur in southern U.S. waterways in high densities, but little is known about the interaction between native fish predators and zebra mussels. Previous studies have suggested that exotic zebra mussels are low profitability prey items and native vertebrate predators are unlikely to reduce zebra mussel densities. We tested these hypotheses by observing prey use of fishes, determining energy content of primary prey species of fishes, and conducting predator exclusion experiments in Lake Dardanelle, Arkansas. 2. Zebra mussels were the primary prey eaten by 52.9% of blue catfish, Ictalurus furcatus; 48.2% of freshwater drum, Aplodinotus grunniens; and 100% of adult redear sunfish, Lepomis microlophus. Blue catfish showed distinct seasonal prey shifts, feeding on zebra mussels in summer and shad, Dorosoma spp., during winter. Energy content (joules g-1) of blue catfish prey (threadfin shad, Dorosoma petenense; gizzard shad, D. cepedianum; zebra mussels; and asiatic clams, Corbicula fluminea) showed a significant species by season interaction, but shad were always significantly greater in energy content than bivalves examined as either ash-free dry mass or whole organism dry mass. Fish predators significantly reduced densities of large zebra mussels (>5 mm length) colonising clay tiles in the summers of 1997 and 1998, but predation effects on small zebra mussels (???5 mm length) were less clear. 3. Freshwater drum and redear sunfish process bivalve prey by crushing shells and obtain low amounts of higher-energy food (only the flesh), whereas blue catfish lack a shell-crushing apparatus and ingest large amounts of low-energy food per unit time (bivalves with their shells). Blue catfish appeared to select the abundant zebra mussel over the more energetically rich shad during summer, then shifted to shad during winter when shad experienced temperature-dependent stress and mortality. Native fish predators can suppress adult zebra

  3. Mollusks (Gastropoda and Bivalvia) of the Multiple-Use Reserve Martín García Island, Río de la Plata River: biodiversity and ecology.

    Science.gov (United States)

    César, I I; Martín, S M; Rumi, A; Tassara, M

    2012-02-01

    The Island of Martin Garcia is located in the Upper Río de la Plata, to the south of mouth the Uruguay River. The aim of the present study was to analyse the biodiversity of the island freshwater mollusks and their relationships to environmental variables. Twelve sampling sites were selected, five were along the littoral section of the island and seven were Inland ponds. Seven major environmental variables were measured: water and air temperature, percentage of oxygen saturation, dissolved oxygen, electrical conductivity, total dissolved solids and pH. Twenty-seven mollusk species were found, Antillorbis nordestensis, Biomphalaria tenagophila tenagophila , B. t. guaibensis, B. straminea, B. peregrina, Drepanotrema kermatoides, D. cimex, D. depressissimum, Chilina fluminea, C. rushii, C. megastoma, Uncancylus concentricus, Hebetancylus moricandi, Stenophysa marmorata, Heleobia piscium, H. parchappii, Potamolithus agapetus, P. buschii, P. lapidum, Pomacea canaliculata, P. megastoma, Asolene platae, Corbicula fluminea, Eupera platensis, Pisidium sterkianum, P. taraguyense and Limnoperna fortunei. UPGMA clustering of species based on their occurrence in different ecological conditions revealed two main species groups. The Canonical Correspondence Analysis suggests that the species distribution is related to the physico-chemical condition of water. Axis two of the ordination diagram displayed the approximately 95.6% of the correlation between species and environmental variables. Dissolved oxygen, conductivity, water temperature and pH showed the highest fluctuations during the sampling period. The species richness (S) showed relationships mainly with water temperature and conductivity. The biodiversity of the gastropods and bivalves from Martín García Island amounts to up to 26 species. Among the Gastropoda, the Planorbidae family made the most sizeable contribution. The Lithogliphidae P. agapetus (26.28%) and P. buschii (9.50%) showed the highest relative

  4. SAR Indicators for Morphological Changes and Bivalve Beds on Intertidal Flats

    Science.gov (United States)

    Gade, Martin; Melchionna, Sabrina; Kemme, Linnea

    2016-08-01

    We analysed a large amount of high-resolution Synthetic Aperture Radar (SAR) data of dry-fallen intertidal flats on the German North Sea coast with respect to the imaging of sediments, macrophytes, and mussels. TerraSAR-X and Radarsat-2 images of four test areas acquired from 2008 to 2013 form the basis for the present investigation and are used to demonstrate that pairs of SAR images, if combined through basic algebraic operations, can already provide indicators for morphological changes and for bivalve (oyster and mussel) beds. Multi-temporal analyses of series of SAR images allow detecting bivalve beds, since the radar backscattering from those beds is generally high, whereas that from sediments may vary with imaging geometry and environmental conditions. Our results further show evidence that also single-acquisition, dual- polarization SAR imagery can be used in this respect. The polarization coefficient (i.e., the ratio of the difference and the sum of both co-polarizations) can be used to infer indicators for oyster and blue-mussel beds.

  5. Physiological effects of hypercapnia in the deep-sea bivalve Acesta excavata (Fabricius, 1779) (Bivalvia; Limidae)

    DEFF Research Database (Denmark)

    Hammer, Karen M.; Kristiansen, Erlend; Zachariassen, Karl Erik

    2011-01-01

    The option of storing CO(2) in subsea rock formations to mitigate future increases in atmospheric CO(2) may induce problems for animals in the deep sea. In the present study the deep-sea bivalve Acesta excavata was subjected to environmental hypercapnia (pHSW 6.35, P(CO2), =33,000 mu atm) corresp......The option of storing CO(2) in subsea rock formations to mitigate future increases in atmospheric CO(2) may induce problems for animals in the deep sea. In the present study the deep-sea bivalve Acesta excavata was subjected to environmental hypercapnia (pHSW 6.35, P(CO2), =33,000 mu atm......) corresponding to conditions reported from natural CO(2) seeps. Effects on acid base status and metabolic rate were related to time of exposure and subsequent recovery. During exposure there was an uncompensated drop in both hemolymph and intracellular pH. Intracellular pH returned to control values, while...... extracellular pH remained significantly lower during recovery. Intracellular non-bicarbonate buffering capacity of the posterior adductor muscle of hypercapnic animals was significantly lower than control values, but this was not the case for the remaining tissues analyzed. Oxygen consumption initially dropped...

  6. Norovirus in bivalve molluscs: a study of the efficacy of the depuration system

    Directory of Open Access Journals (Sweden)

    Giovanni Savini

    2009-12-01

    Full Text Available Noroviruses are the most common viral agents of acute gastroenteritis in humans and are often associated with the consumption of either fresh or undercooked live bivalve molluscs. The aim of the study was to evaluate the efficacy of the water depuration systems in the presence of Norovirus contamination A total of 96 shellfish samples was examined by reverse transcriptase-polymerase chain reaction, as follows: 58 mussel samples (Mytilus galloprovincialis, 35 Manila clam samples (Tapes decussatus and 3 Pacific oyster samples (Crassostrea gigas. Of these, 67 were collected before and 29 following depuration. Viral RNA was detected in one of the 67 non-depurated samples examined (1.5%; 95% confidence interval: 0.36-7.92% and in one of the 29 depurated samples (3.4%; 95% confidence interval: 0.82-17.22%. There were no statistically significant differences between depurated and non-depurated samples which indicated that the purifying systems in place were not able to remove Norovirus contamination from the live bivalve molluscs.

  7. THE USE OF ALGAE CONCENTRATES, DRIED ALGAE AND ALGAL SUBSTITUTES TO FEED BIVALVES

    Directory of Open Access Journals (Sweden)

    Ludi Parwadani Aji

    2011-01-01

    Full Text Available Microalgae have high nutritional value and are used to feed adult and larval stages of bivalves, the larvae of some fish and crustaceans and zooplankton. However, microalgae production for aquaculture animal is very expensive. To overcome this, the use of preserved microalgae such as algae concentrate and dried algae, or algal substitutes has been developed. There are both advantages and disadvantages to this alternative food. For example, even though the cost production for algal substitute yeast-based diet is cheaper, their nutritional value is much lower compared to fresh microalgae. Moreover, there is no significant difference in nutritional value between preserved (concentrated or dried and fresh microalgae; however, preserving microalgae for long periods will affect their nutritional value. In spite of this problem, preserved microalgae such as algal concentrate and dried algae seem to be more effective to feed bivalves than algal substitutes yeast based diet due to their availability and relatively high nutritional value. Furthermore, algae concentrates are more suitable to replace fresh algae than dried algae.

  8. Titanium dioxide nanoparticles as carrier facilitate bioaccumulation of phenanthrene in marine bivalve, ark shell (Scapharca subcrenata).

    Science.gov (United States)

    Tian, Shengyan; Zhang, Yaodan; Song, Chunzheng; Zhu, Xiaoshan; Xing, Baoshan

    2014-09-01

    To evaluate the impact of titanium dioxide nanoparticles (nTiO2) on the uptake of hydrophobic organic chemicals by marine bivalves, we conducted a comparative bioaccumulation study by exposing clam, Scapharca subcrenata, to phenanthrene (Phe) in the presence and absence of nTiO2. The large surface area of nTiO2 resulted in adsorption of co-existing Phe in aqueous solution to form nTiO2-Phe complexes. Accumulation of nTiO2 was not observed in clams at exposed concentration (500 μg/L) in this study. However, enhanced uptake of Phe by clams was observed in the presence of nTiO2, with ku and BAFs values being 2 and 1.7 times higher than that of Phe alone, respectively. The enhanced uptake can be explained by ingestion of nTiO2-Phe complexes into the gut and subsequent desorption of Phe there. Therefore, nTiO2 as a carrier facilitated the uptake of Phe by marine bivalves.

  9. Bivalve Omics: State of the Art and Potential Applications for the Biomonitoring of Harmful Marine Compounds

    Directory of Open Access Journals (Sweden)

    Paola Venier

    2013-11-01

    Full Text Available The extraordinary progress experienced by sequencing technologies and bioinformatics has made the development of omic studies virtually ubiquitous in all fields of life sciences nowadays. However, scientific attention has been quite unevenly distributed throughout the different branches of the tree of life, leaving molluscs, one of the most diverse animal groups, relatively unexplored and without representation within the narrow collection of well established model organisms. Within this Phylum, bivalve molluscs play a fundamental role in the functioning of the marine ecosystem, constitute very valuable commercial resources in aquaculture, and have been widely used as sentinel organisms in the biomonitoring of marine pollution. Yet, it has only been very recently that this complex group of organisms became a preferential subject for omic studies, posing new challenges for their integrative characterization. The present contribution aims to give a detailed insight into the state of the art of the omic studies and functional information analysis of bivalve molluscs, providing a timely perspective on the available data resources and on the current and prospective applications for the biomonitoring of harmful marine compounds.

  10. Traces (ichnospecies Oichnus paraboloides of predatory gastropods on bivalve shells from the Seogwipo Formation, Jejudo, Korea

    Directory of Open Access Journals (Sweden)

    Dal-Yong Kong

    2015-12-01

    Full Text Available Circular to subcircular drill holes were identified on the bivalve shells collected from the Seogwipo Formation, Jejudo, Korea. A great majority of the drill holes (>70% were found on the surfaces of a bivalve species Glycymeris rotunda. They are characterized by a beveled sharp edge and paraboloid in cross section with larger outer borehole diameter (OBD; mean 4.21 mm and smaller inner borehole diameter (mean 2.94 mm. Walls of the drill holes are generally smooth, and walls ornamented with etched relief-like structures were also recognized. A slightly raised central boss observed in an incomplete specimen may indicate a failure of predator’s attack. All drill holes collected are classified as a single ichnospecies Oichnus paraboloides Bromley, 1981. They are interpreted as boring traces produced by predatory gastropods, particularly naticid gastropods. Most O. paraboloides boreholes are observed in the central area of shell surfaces; a few boreholes lie marginally, which may reflect a borehole-site selectivity. No correlation between size of prey (shell height and size of predator (OBD is recognized. It is likely, however, that drilled shells of about 30 mm in height represent optimal prey size for naticid predators that lived in a benthic Seogwipo community.

  11. Assessment of Heavy Metals in Bivalves Molluscs of Apulian Region: a 3-years control activity of a EU Laboratory

    Directory of Open Access Journals (Sweden)

    Miedico O.

    2013-04-01

    Full Text Available The bivalve molluscs represent an important matrix to be studied for several reasons. Their nutritional properties make them valuable to the consumers, so that their consumption and commercial value has risen worldwide. Simultaneously, their significant water-filtering capability and their persistence in the same place make them good bio-indicators of marine ecosystems. The presence of the heavy metal contaminants, as Cd, Pb and Hg, was investigated in bivalve molluscs such as mussels (Mytilus galloprovincialis, clams (Venus gallina and oysters (Ostrea edulis. In the present study, a survey was carried out on 334 samples addressed to the Istituto Zooprofilattico Sperimentale – Puglia e Basilicata, Foggia (ITALY between 2009-2011, and collected by official authorities along the coasts of Apulia Region. The conformity of heavy metal content in bivalve molluscs was verified, in according to EC Reg. 1881/2006. The compliance was found for the total amount of samples. The obtained data on heavy metals concentration in bivalve molluscs were compared with data found in monitoring studies on the incidence of heavy metals in 1981 in North-Western Mediterranean Sea, in 2003 in Tyrrhenian Sea and in 2010 in Pacific Ocean (Chile, reported in literature. The information obtained from this work offer an essential database, not only for the authorities involved in food control, but also for the official institutions responsible of a constant control of the marine ecosystem pollution.

  12. Occurrence of pharmaceuticals and endocrine disrupting compounds in macroalgaes, bivalves, and fish from coastal areas in Europe

    NARCIS (Netherlands)

    Álvarez-Muñoz, D.; Rodríguez-Mozaz, S.; Maulvault, A.L.; Tediosi, A.; Fernández-Tejedor, M.; Heuvel, Van den F.; Kotterman, M.; Marques, A.; Barceló, D.

    2015-01-01

    The ocurrence and levels of PhACs, Endocrine Disrupting and related Compounds (EDCs) in seafood from potential contaminated areas in Europe has been studied. Macroalgae (S. accharina latissima and Laminaria digitata), bivalves (Mytilus galloprovincialis, Mytilus spp., Chamalea gallina and Crassos

  13. Growth and size-dependent loss of newly settled bivalves in two distant regions of the Wadden Sea

    NARCIS (Netherlands)

    Andresen, H.; Dorresteijn, I.; van der Meer, J.

    2013-01-01

    Individual growth and the timing of life history events determine the course of individual body sizes. Hence, these factors can influence size-dependent species interactions, such as predation. In the Wadden Sea, predation by crustaceans plays an important role in the survival of pre-recruit bivalve

  14. Uniform Variation in Genetic-Traits of a Marine Bivalve Related to Starvation, Pollution and Geographic Clines

    NARCIS (Netherlands)

    Hummel, H.; Bogaards, R.H.; Amiard-Triquet, C.; Bachelet, G.; Desprez, M.; Marchand, J.; Rybarczyk, H.; Sylvand, B.; De Wit, Y.; De Wolf, L.

    1995-01-01

    Consistent patterns of genetic variation in the marine bivalve Macoma balthica (L.) were found after exposure to low levels of copper, starvation, and along geographic dines. The geographic dines were related to temperature and salinity. Genetic differences were primarily found in the LAP (Leucine a

  15. Biologically induced deposition of fine suspended particles by filter-feeding bivalves in land-based industrial marine aquaculture wastewater.

    Science.gov (United States)

    Zhou, Yi; Zhang, Shaojun; Liu, Ying; Yang, Hongsheng

    2014-01-01

    Industrial aquaculture wastewater contains large quantities of suspended particles that can be easily broken down physically. Introduction of macro-bio-filters, such as bivalve filter feeders, may offer the potential for treatment of fine suspended matter in industrial aquaculture wastewater. In this study, we employed two kinds of bivalve filter feeders, the Pacific oyster Crassostrea gigas and the blue mussel Mytilus galloprovincialis, to deposit suspended solids from marine fish aquaculture wastewater in flow-through systems. Results showed that the biodeposition rate of suspended particles by C. gigas (shell height: 8.67 ± 0.99 cm) and M. galloprovincialis (shell height: 4.43 ± 0.98 cm) was 77.84 ± 7.77 and 6.37 ± 0.67 mg ind(-1) • d(-1), respectively. The total solid suspension (TSS) deposition rates of oyster and mussel treatments were 3.73 ± 0.27 and 2.76 ± 0.20 times higher than that of the control treatment without bivalves, respectively. The TSS deposition rates of bivalve treatments were significantly higher than the natural sedimentation rate of the control treatment (P aquaculture wastewater, and simultaneously yield value-added biological products.

  16. Lineage tracing of the bivalve shell field with special interest in the descendants of the 2d blastomere.

    Science.gov (United States)

    Mohri, Masakuni; Hashimoto, Naoki; Wada, Hiroshi

    2016-03-01

    By evolving bilaterally separated shell plates, bivalves acquired a unique body plan in which their soft tissues are completely protected by hard shell plates. In this unique body plan, mobility between the separated shell plates is provided by novel structures such as a ligament and adductor muscles. As a first step towards understanding how the bivalve body plan was established, we investigated the development of the separated shell plates and ligament. Over 100 years ago, it was hypothesized that the development of separated shell plates is tightly linked with the unique cell cleavage (division) pattern of bivalves during development, wherein each bilateral daughter cell of the 2d descendant 2d(1121) develops into one of the bilateral shell fields. In this study, we tested this hypothesis by tracing the cell lineages of the Japanese purple mussel Septifer virgatus. Although the shell fields were found to be exclusively derived from the bilateral descendant cells of 2d: 2d(11211) and 2d(11212), the descendants of these cells were not restricted to shell fields alone, nor were they confined to the left or right side of the shell field based on their lineage. Our study demonstrated that ligament cells are also derived from 2d(11211) and 2d(11212), indicating that the ligament cells emerged as a subpopulation of shell field cells. This also suggests that the establishment of the novel developmental system for the ligament cells was critical for the evolution of the unique body plan of bivalves.

  17. Variation of the physiological energetics of the bivalve Spisula subtruncata (da Costa, 1778) within an annual cycle

    NARCIS (Netherlands)

    Rueda, J.L.; Smaal, A.C.

    2004-01-01

    Spisula subtruncata is an infaunal filter-feeding bivalve, which lives in shallow sandy bottoms (2¿20 m depth) from Norway to the Atlantic coasts of Morocco, including the Mediterranean Sea. Considering that fisheries of this species have become an important economic resource in some European countr

  18. Disjunct distribution of highly diverged mitochondrial lineage clade and population subdivision in a marine bivalve with pelagic larval dispersal

    NARCIS (Netherlands)

    Luttikhuizen, PC; Drent, J; Baker, AJ

    2003-01-01

    Mitochondrial DNA sequence data for 295 individuals of the marine bivalve Macoma balthica (L.) were collected from 10 sites across the European distribution, and from Alaska. The data were used to infer population subdivision history and estimate current levels of gene flow. Inferred historical biog

  19. The Ghost in the Shell : Local and Remote Forcing of a Coastal Bivalve Inhabiting the Humboldt Current System

    Science.gov (United States)

    Gosselin, M.

    2014-12-01

    The external skeleton of mollusc bivalves, the shell, can furnish a recording of the environmental changes to which the organisms and population are exposed during their lives. The bivalve's growth is subjected to the thermocline variability; which itself is affected by environmental and climatic events. A highly variable environment such as the Humboldt current system (HCS) requires tools capable of recording its variations over a wide range of periodicities. Upwelling, Coastal trapped waves (CTWs), El Niño Southern Oscillation, and Pacific decadal oscillation events contribute to this environmental and climatic variability. The thermocline depth is modified by these different events at their own time-scales (respectively, daily to weekly, intraseasonally, interseasonally to interannually, and on a decadal scale). The thermocline variation translates into changes in Sea surface temperature (SST) and in the qualitative and quantitative productivity of phytoplankton. These two environmental factors are critical to bivalve growth.The sclerochronological (increment width) and sclerochemical (δ18O and δ13C) study consisted on the analysis of the Chilean bivalve Eurhomalea rufa, collected in 2005, as a recorder of the environmental HCS variability. The calibration step identified daily, monthly, and annual marks in the growth patterns of E. rufa. The results confirmed that the thermocline variability mainly drives the bivalve's activity and led to the establishment of a paleotemperature equation. Moreover, periodogram and wavelet analyses exposed the respective impacts of each environmental event from daily to interannual periodicities. In particular, the growth pattern of E. rufa follows SST variability at an intraseasonal periodicity (~ 60 days) which is remotely induced by CTWs. CTWs are generated by Kelvin oceanic waves, which are formed primarily by eastward equatorial Pacific winds (e.g. Shaffer et al. 1997; Montecino and Lange 2009).Sclerochronological studies

  20. UTILISATION DU MODÈLE ÉCREVISSE COMME ESPÈCE BIOINDICATRICE DE POLLUTION. APPLICATION À L’ÉTUDE DES TRANSFERTS TROPHIQUES DU CADMIUM

    Directory of Open Access Journals (Sweden)

    SIMON O.

    2002-07-01

    Full Text Available La bioaccumulation des métaux par les organismes aquatiques est directement liée aux modalités d’exposition : contamination directe via le milieu ou contamination trophique via l’ingestion de proies contaminées. Pour appréhender les perturbations des écosystèmes, il apparaît important de déterminer des espèces « bioindicatrices » et de mesurer la part respective de ces deux voies d’exposition. Les travaux présentés concernent le transfert trophique du cadmium entre une proie, le bivalve benthique Corbicula fluminea, et un de ses prédateurs, l’écrevisse Astacus astacus. Afin d’insister sur l’importance des modalités de prédation de ce crustacé, nous avons réalisé 2 approches expérimentales complémentaires. La première concerne la consommation « naturelle » de proies contaminées pendant 30 jours d’exposition, la seconde consiste à introduire directement un bol alimentaire de proies contaminées dans l’estomac des écrevisses par une technique de gavage. Les résultats montrent une différence importante entre ces deux approches expérimentales.

  1. Influences of organic matter and calcification rate on trace elements in aragonitic estuarine bivalve shells

    Science.gov (United States)

    Takesue, R.K.; Bacon, C.R.; Thompson, J.K.

    2008-01-01

    A suite of elements (B, Na, Mg, S, K, Ca, V, Mn, Cr, Sr, and Ba) was measured in aragonitic shells of the estuarine bivalve Corbula amurensis, the Asian clam, using the Sensitive High-Resolution Ion MicroProbe with Reverse Geometry (SHRIMP RG). Our initial intent was to explore potential geochemical proxy relationships between shell chemistry and salinity (freshwater inflow) in northern San Francisco Bay (SFB). In the course of this study we observed variations in shell trace element to calcium ([M]/Ca) ratios that could only be attributed to internal biological processes. This paper discusses the nature and sources of internal trace element variability in C. amurensis shells related to the shell organic fraction and shell calcification rates. The average organic content of whole C. amurensis shells is 19%. After treating whole powdered shells with an oxidative cleaning procedure to remove organic matter, shells contained on average 33% less total Mg and 78% less total Mn. Within our analytical uncertainty, Sr and Ba contents were unchanged by the removal of organic matter. These results show that aragonitic C. amurensis shells have a large component of non-lattice-bound Mg and Mn that probably contribute to the dissimilarity of [M]/Ca profiles among five same-sized shells. Non-lattice-bound trace elements could complicate the development and application of geochemical proxy relationships in bivalve shells. Because B, Ba and Sr occur exclusively in shell aragonite, they are good candidates for external proxy relationships. [M]/Ca ratios were significantly different in prismatic and nacreous aragonite and in two valves of the same shell that had different crystal growth rates. Some part of these differences can be attributed to non-lattice-bound trace elements associated with the organic fraction. The differences in [M]/Ca ratios were also consistent with the calcification rate-dependent ion transport model developed by Carr?? et al. [Carr?? M., Bentaleb I

  2. Short and long term consequences of larval stage exposure to constantly and ephemerally elevated carbon dioxide for marine bivalve populations

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    C. J. Gobler

    2012-11-01

    Full Text Available While larval bivalves are highly sensitive to ocean acidification, the basis for this sensitivity and the longer term implications of this sensitivity are unclear. Experiments were performed to assess the short term (days and long term (months consequences of larval stage exposure to varying CO2 concentrations for calcifying bivalves. Higher CO2 concentrations depressed both calcification rates assessed using 45Ca uptake and RNA:DNA ratios in Mercenaria mercenaria and Argopecten irradians larvae with RNA:DNA ratios being highly correlated with larval growth rates r2 > 0.9. These findings suggested that high CO2 has a cascading negative physiological impact on bivalve larvae stemming in part from lower calcification rates. Exposure to elevated CO2 during the first four days of larval development significantly depressed A. irradians larval survival rates, while a 10 day exposure later in larval development did not, demonstrating the extreme CO2-sensitivity of bivalve larvae during first days of development. Short- (weeks and long-term (10 month experiments revealed that individuals surviving exposure to high CO2 during larval development grew faster when exposed to normal CO2 as juveniles compared to individuals reared under ambient CO2 as larvae. These increased growth rates could not, however, overcome size differences established during larval development, as size deficits of individuals exposed to even moderate levels of CO2 as larvae were evident even after 10 months of growth under normal CO2 concentrations. This `legacy effect' emphasizes the central role larval stage CO2 exposure can play in shaping the success of modern day bivalve populations.

  3. Biologically induced deposition of fine suspended particles by filter-feeding bivalves in land-based industrial marine aquaculture wastewater.

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    Yi Zhou

    Full Text Available Industrial aquaculture wastewater contains large quantities of suspended particles that can be easily broken down physically. Introduction of macro-bio-filters, such as bivalve filter feeders, may offer the potential for treatment of fine suspended matter in industrial aquaculture wastewater. In this study, we employed two kinds of bivalve filter feeders, the Pacific oyster Crassostrea gigas and the blue mussel Mytilus galloprovincialis, to deposit suspended solids from marine fish aquaculture wastewater in flow-through systems. Results showed that the biodeposition rate of suspended particles by C. gigas (shell height: 8.67 ± 0.99 cm and M. galloprovincialis (shell height: 4.43 ± 0.98 cm was 77.84 ± 7.77 and 6.37 ± 0.67 mg ind(-1 • d(-1, respectively. The total solid suspension (TSS deposition rates of oyster and mussel treatments were 3.73 ± 0.27 and 2.76 ± 0.20 times higher than that of the control treatment without bivalves, respectively. The TSS deposition rates of bivalve treatments were significantly higher than the natural sedimentation rate of the control treatment (P < 0.001. Furthermore, organic matter and C, N in the sediments of bivalve treatments were significantly lower than those in the sediments of the control (P < 0.05. It was suggested that the filter feeders C. gigas and M. galloprovincialis had considerable potential to filter and accelerate the deposition of suspended particles from industrial aquaculture wastewater, and simultaneously yield value-added biological products.

  4. Coexistence of Pacific oyster Crassostrea gigas (Thunberg, 1793) and blue mussels Mytilus edulis Linnaeus, 1758 on a sheltered intertidal bivalve bed?

    DEFF Research Database (Denmark)

    Holm, M.W.; Davids, J.K.; Dolmer, Per;

    2016-01-01

    The invasive Pacific oyster, Crassostrea gigas Thunberg, 1793 was introduced in Denmark for aquaculture in the 1970s. Presently, feral populations are found in many parts of the country, with the largest populations established on existing beds of blue mussel, Mytilus edulis Linnaeus, 1758...... and M. edulis were collected from the bivalve bed, shell lengths were converted into biomass, which were interpolated to create biomass contours and combined with modelled topography of the bivalve bed to study niche separation. The bivalve bed slowly extended northwards over a period of 11 years, where...

  5. Field clearance of an intertidal bivalve bed: relative significance of the co-occurring blue mussel Mytilus edulis and Pacific oyster Crassostrea gigas

    DEFF Research Database (Denmark)

    Vismann, Bent; Holm, Mark Wejlemann; Davids, Jens;

    2016-01-01

    At an approximately 12 000 m2 sheltered intertidal bivalve bed in the western part of the Limfjord, Denmark, the Pacific oyster Crassostrea gigas co-occurs with the blue mussel Mytilus edulis. The relative significance of the impact of the 2 species on phytoplankton density during a tidal cycle....... However, the estimated water column cleared during low tide is overestimated due to phytoplankton depletion. Hence, it is concluded that the bivalve bed clears the water close to 1 time each tidal cycle. This, together with a low dry weight of soft parts, indicates that the bivalve bed, in general...

  6. Bioaccumulation of heavy metals by bivalves from lim fjord (North Adriatic Sea)

    Energy Technology Data Exchange (ETDEWEB)

    Martincic, D.; Nurnberg, H.W.; Stoeppler, M.; Branica, M.

    1984-08-01

    The accumulation of trace metals (Zn, Cd, Pb, and Cu) by two bivalves (Mytilus galloprovincialis and Ostrea edulis) growing at the same station and therefore under the same physicochemical conditions was studied. The oysters were more effective bioaccumulators for zinc, cadmium, lead and copper than the mussels. Oysters accumulate about 10-fold higher quantities of zinc than mussels, 16-fold higher for copper, 3-fold higher cadmium, and 2-fold higher lead concentrations. The observed differences in the copper and zinc distribution within the investigated organs can be attributed to some recently recognized blood cells in the oyster which are rich in zinc and copper. The tissue copper and zinc distribution in this animal depends on where these cells are at the time of sampling. The mussel contains no such cells. 53 references, 7 figures, 1 table.

  7. Turnover of postlarval bivalves in sediments of tidal flats in Königshafen (German Wadden sea)

    Science.gov (United States)

    Armonies, W.

    1994-06-01

    After larval settlement, juvenile bivalves may rapidly re-enter the water column and attain secondary dispersal by byssus-drifting. In order to estimate the quantitative importance of byssus-drifting, the abundance of drifters in the water column, their re-entry into the sediment, and their density in the ambient sediment were measured simultaneously over 3 months on a tidal flat in Königshafen near the Island of Sylt in the North Sea. Turnover of juvenile clams Macoma balthica and cockles Cerastoderma edule was more than once per week in summer, showing strong short-term variability because of semi-lunar rhythms of drifting activity. While there is currently no evidence for active habitat selection in settling M. balthica and C. edule larvae, it is suggested that habitat selection occurs following postlarval migrations.

  8. Clarifying phylogenetic relationships and the evolutionary history of the bivalve order Arcida (Mollusca: Bivalvia: Pteriomorphia).

    Science.gov (United States)

    Combosch, David J; Giribet, Gonzalo

    2016-01-01

    The systematics of the bivalve order Arcida constitutes an unresolved conundrum in bivalve systematics. The current definition of Arcida encompasses two superfamilies: Limopsoidea, which includes the recent families Philobryidae and Limopsidae, and Arcoidea, which encompasses the families Arcidae, Cucullaeidae, Noetiidae, Glycymerididae and Parallelodontidae. This classification, however, is controversial particularly with respect to the position and taxonomic status of Glycymerididae. Previous molecular phylogenies were limited either by the use of only a single molecular marker or by including only a few limopsoid and glycymeridid taxa. The challenging nature of Arcida taxonomy and the controversial results of some of the previous studies, prompted us to use a broad range of taxa (55 species), three nuclear markers (18S rRNA, 28S rRNA and histone H3) and a wide range of algorithmic approaches. This broad but stringent approach led to a number of results that differ significantly from previous studies. We provide the first molecular evidence that supports the separation of Arcoidea from Limopsoidea, although the exact position of Glycymerididae remains unresolved, and the monophyly of Limopsoidea is algorithm-dependent. In addition, we present the first time-calibrated evolutionary tree of Arcida relationships, indicating a significant increase in the diversification of arcidan lineages at the beginning of the Cretaceous, around 140Ma. The monophyly of Arcida, which has been supported previously, was confirmed in all our analyses. Although relationships among families remain somehow unresolved we found support for the monophyly of most arcidan families, at least under some analytical conditions (i.e., Glycymerididae, Noetiidae, Philobryidae, and Limopsidae). However, Arcidae, and particularly Arcinae, remain a major source of inconsistency in the current system of Arcida classification and are in dire need of taxonomic revision.

  9. Impact of seawater carbonate chemistry on the calcification of marine bivalves

    Science.gov (United States)

    Thomsen, J.; Haynert, K.; Wegner, K. M.; Melzner, F.

    2015-07-01

    Bivalve calcification, particularly of the early larval stages, is highly sensitive to the change in ocean carbonate chemistry resulting from atmospheric CO2 uptake. Earlier studies suggested that declining seawater [CO32-] and thereby lowered carbonate saturation affect shell production. However, disturbances of physiological processes such as acid-base regulation by adverse seawater pCO2 and pH can affect calcification in a secondary fashion. In order to determine the exact carbonate system component by which growth and calcification are affected it is necessary to utilize more complex carbonate chemistry manipulations. As single factors, pCO2 had no effects and [HCO3-] and pH had only limited effects on shell growth, while lowered [CO32-] strongly impacted calcification. Dissolved inorganic carbon (CT) limiting conditions led to strong reductions in calcification, despite high [CO32-], indicating that [HCO3-] rather than [CO32-] is the inorganic carbon source utilized for calcification by mytilid mussels. However, as the ratio [HCO3-] / [H+] is linearly correlated with [CO32-] it is not possible to differentiate between these under natural seawater conditions. An equivalent of about 80 μmol kg-1 [CO32-] is required to saturate inorganic carbon supply for calcification in bivalves. Below this threshold biomineralization rates rapidly decline. A comparison of literature data available for larvae and juvenile mussels and oysters originating from habitats differing substantially with respect to prevailing carbonate chemistry conditions revealed similar response curves. This suggests that the mechanisms which determine sensitivity of calcification in this group are highly conserved. The higher sensitivity of larval calcification seems to primarily result from the much higher relative calcification rates in early life stages. In order to reveal and understand the mechanisms that limit or facilitate adaptation to future ocean acidification, it is necessary to better

  10. [Aeromonas spp. and Plesiomonas shigelloides in bivalves, mud, and water from the Gulf of Nicoya, Costa Rica].

    Science.gov (United States)

    Rodríguez, E; Antillón, F

    1989-06-01

    Bivalves, mud, and surface water were collected at three different sites of the Gulf of Nicoya, Costa Rica, in search of Aeromonas spp. and Plesiomonas shigelloides. For their isolation, these bacteria were enriched in alkaline peptone water and streaked on MacConkey agar and on brilliant green bile inositol agar. This was followed by the biochemical tests necessary for their identification. Thirty-five strains of A. hydrophila, 58 of A. caviae, 43 of A. sobria, and 7 of P. shigelloides were isolated. None of these predominated nor was there any indication of a seasonal distribution along the 15 month's duration of the study. Seven strains of A. hydrophila and two of A. sobria showed the biochemical characteristics associated with toxin production (positive Voges-Proskauer and lysine decarboxylase tests). These species are widely distributed in the gulf and there is risk of contracting an infection while bathing or when eating raw bivalves from this area.

  11. [Bacteriological study of bivalves from the Gulf of Nicoya, Costa Rica. I. Condition of the mollusk recently collected].

    Science.gov (United States)

    Fernández, B; Brunker, T

    1977-07-01

    During the first six months of 1970 we collected 16 lots of the bivalve Anadara tuberculosa from two areas within the Gulf of Nicoya, Costa Rica. These were examined bacteriologically and the coliform levels found in all of them were such that they had to be graded as not satisfactory for human consumption, according to generally accepted norms. The source of these coliforms is attributed to the sewage discharge of the city of Puntarenas into its estuary.

  12. Stable isotopes in bivalves as indicators of nutrient source in coastal waters in the Bocas del Toro Archipelago, Panama.

    Science.gov (United States)

    Graniero, Lauren E; Grossman, Ethan L; O'Dea, Aaron

    2016-01-01

    To examine N-isotope ratios ((15)N/(14)N) in tissues and shell organic matrix of bivalves as a proxy for natural and anthropogenic nutrient fluxes in coastal environments, Pinctada imbricata, Isognomon alatus, and Brachidontes exustusbivalves were live-collected and analyzed from eight sites in Bocas del Toro, Panama. Sites represent a variety of coastal environments, including more urbanized, uninhabited, riverine, and oceanic sites. Growth under differing environmental conditions is confirmed by δ (18)O values, with open ocean Escudo de Veraguas shells yielding the highest average δ (18)O (-1.0‰) value and freshwater endmember Rio Guarumo the lowest (-1.7‰). At all sites there is no single dominant source of organic matter contributing to bivalve δ (15)N and δ (13)C values. Bivalve δ (15)N and δ (13)C values likely represent a mixture of mangrove and seagrass N and C, although terrestrial sources cannot be ruled out. Despite hydrographic differences between end-members, we see minimal δ (15)N and δ (13)C difference between bivalves from the river-influenced Rio Guarumo site and those from the oceanic Escudo de Veraguas site, with no evidence for N from open-ocean phytoplankton in the latter. Populated sites yield relative (15)N enrichments suggestive of anthropogenic nutrient input, but low δ (15)N values overall make this interpretation equivocal. Lastly, δ (15)N values of tissue and shell organic matrix correlate significantly for pterioideans P. imbricata and I. alatus. Thus for these species, N isotope studies of historical and fossil shells should provide records of ecology of past environments.

  13. Field chronobiology of a molluscan bivalve: how the moon and sun cycles interact to drive oyster activity rhythms.

    Science.gov (United States)

    Tran, Damien; Nadau, Arnaud; Durrieu, Gilles; Ciret, Pierre; Parisot, Jean-Paul; Massabuau, Jean-Charles

    2011-05-01

    The present study reports new insights into the complexity of environmental drivers in aquatic animals. The focus of this study was to determine the main forces that drive mollusc bivalve behavior in situ. To answer this question, the authors continuously studied the valve movements of permanently immersed oysters, Crassostrea gigas, during a 1-year-long in situ study. Valve behavior was monitored with a specially build valvometer, which allows continuously recording of up to 16 bivalves at high frequency (10 Hz). The results highlight a strong relationship between the rhythms of valve behavior and the complex association of the sun-earth-moon orbital positions. Permanently immersed C. gigas follows a robust and strong behavior primarily driven by the tidal cycle. The intensity of this tidal driving force is modulated by the neap-spring tides (i.e., synodic moon cycle), which themselves depend of the earth-moon distance (i.e., anomalistic moon cycle). Light is a significant driver of the oysters' biological rhythm, although its power is limited by the tides, which remain the predominant driver. More globally, depending where in the world the bivalves reside, the results suggest their biological rhythms should vary according to the relative importance of the solar cycle and different lunar cycles associated with tide generation. These results highlight the high plasticity of these oysters to adapt to their changing environment.

  14. [Community structure of bivalves and gastropods in roots of red mangrove Rhizophora mangle (Rhizophoraceae) in isla Larga, Mochima Bay, Venezuela].

    Science.gov (United States)

    Acosta Balbas, Vanessa; Betancourt Tineo, Rafael; Prieto Arcas, Antulio

    2014-06-01

    The Rhizophora mangle roots form a complex ecosystem where a wide range of organisms are permanently established, reproduce, and find refuge. In this study, we assessed the diversity of bivalves and gastropods that inhabit red mangrove roots, in isla Larga, Mochima, Venezuela Sucre state. Bimonthly collections were made from January 2007 to May 2008, in four study areas denominated: South, North, East and West. In each area, five mangrove roots were sampled, and the specimens were obtained. We analyzed a total of 180 roots and a total of 35 bivalve species and 25 gastropod species were found. The most abundant bivalves were: Isognomon alatus, Isognomon bicolor, Ostrea equestris, Crassostrea rhizophorae and Brachidontes exustus; among gastropods, the most common where: Littorina angulifera, (Cymatium pileare and Diodora cayenensis. The months with the highest abundances and number of individuals for both groups were January and July 2007, and March 2008. The mangrove ecosystem in isla Larga, presented a number of individuals and species higher than those reported for other regions in Venezuela and the Caribbean.

  15. Polycyclic Aromatic Hydrocarbons in Sediments and Bivalves on the Pacific Coast of Japan: Influence of Tsunami and Fire

    Science.gov (United States)

    Onozato, Mayu; Nishigaki, Atsuko; Okoshi, Kenji

    2016-01-01

    Surface sediments and at least one edible bivalve species (Ruditapes philippinarum, Mytilus galloprovincialis, and Crassostrea gigas) were collected from each of seven intertidal sites in Japan in 2013. The sites had experienced varying levels of tsunami and fire disturbance following the major earthquake of 2011. Eight polycyclic aromatic hydrocarbons (PAHs) were identified and analyzed by gas chromatography–mass spectrometry. Total sediment PAH concentration (CT), the sum of the average concentrations of the eight PAHs, was 21–1447 μg kg-1-dry. Relative to the average level of one type of PAH in sediments collected around Japan in 2002 (benzo[a]pyrene = 21 μg kg-1-dry), five of the seven sites showed concentrations significantly lower than this average in 2013. The CTs for the three bivalves (134–450 μg kg-1-dry) were within the range of the previous reports (2.2–5335 μg kg-1-dry). The data suggest that the natural disaster did not increase PAH concentrations or affect the distribution within sediment or bivalves in Tohoku district. Although PAH concentrations at the sites pose no risk to human health, the findings highlight that the observed PAH levels derive from pre- rather than post-quake processes. PMID:27232189

  16. Polycyclic Aromatic Hydrocarbons in Sediments and Bivalves on the Pacific Coast of Japan: Influence of Tsunami and Fire.

    Directory of Open Access Journals (Sweden)

    Mayu Onozato

    Full Text Available Surface sediments and at least one edible bivalve species (Ruditapes philippinarum, Mytilus galloprovincialis, and Crassostrea gigas were collected from each of seven intertidal sites in Japan in 2013. The sites had experienced varying levels of tsunami and fire disturbance following the major earthquake of 2011. Eight polycyclic aromatic hydrocarbons (PAHs were identified and analyzed by gas chromatography-mass spectrometry. Total sediment PAH concentration (CT, the sum of the average concentrations of the eight PAHs, was 21-1447 μg kg-1-dry. Relative to the average level of one type of PAH in sediments collected around Japan in 2002 (benzo[a]pyrene = 21 μg kg-1-dry, five of the seven sites showed concentrations significantly lower than this average in 2013. The CTs for the three bivalves (134-450 μg kg-1-dry were within the range of the previous reports (2.2-5335 μg kg-1-dry. The data suggest that the natural disaster did not increase PAH concentrations or affect the distribution within sediment or bivalves in Tohoku district. Although PAH concentrations at the sites pose no risk to human health, the findings highlight that the observed PAH levels derive from pre- rather than post-quake processes.

  17. Investigation into Cryptosporidium and Giardia in bivalve mollusks farmed in Sardinia region and destined for human consumption

    Directory of Open Access Journals (Sweden)

    Tiziana Tedde

    2013-06-01

    Full Text Available Cryptosporidium and Giardia are protozoan parasites transmitted by fecal-oral ingestion of (oocysts, and are responsible for enteritis in several animal species and humans worldwide. These (oocysts can survive for over a year in aquatic environments and can accumulate in bivalve mollusks, which filter large volumes of water. The aim of this study is to evaluate the natural occurrence of Cryptosporidium and Giardia contamination in different specimens of edible bivalves mollusks from farming sites of the western and north-eastern coasts of Sardinia. From April 2011 to February 2012, 1095 specimens of Mytilus galloprovincialis and 240 of Crassostrea gigas were sampled from Olbia and Oristano gulf and San Teodoro pond. Hepatopancreas and gills, including the labial palp, were examined for oocysts and cysts after pooling and homogenisation using different techniques: i staining for light and fluorescence microscopy; ii direct immunofluorescence (IF Merifluor® test Cryptosporidium/ Giardia (Meridian Bioscience Inc., Cincinnati, OH, USA; and iii molecular procedures. However, in the context under study, all mollusks examined with the three main diagnostic techniques were negative for both parasites pointing out the hypothetically low zoonotic risk related to Cryptosporidium and Giardia in bivalves, especially Mytilus galloprovincialis and Crassostrea gigas.

  18. Manganese in the shell of the bivalve Mytilus edulis: Seawater Mn or physiological control?

    Science.gov (United States)

    Freitas, Pedro S.; Clarke, Leon J.; Kennedy, Hilary; Richardson, Christopher A.

    2016-12-01

    Manganese in the shell calcite of marine bivalves has been suggested to reflect ambient seawater Mn concentrations, thus providing a high-resolution archive of past seawater Mn concentrations. However, a quantitative relationship between seawater Mn and shell Mn/Ca ratios, as well as clear understanding of which process(es) control(s) shell Mn/Ca, are still lacking. Blue mussels, Mytilus edulis, were grown in a one-year duration field experiment in the Menai Strait, U.K., to study the relationship between seawater particulate and dissolved Mn2+ concentrations and shell calcite Mn/Ca ratios. Shell Mn/Ca showed a well-defined intra-annual double-peak, with maximum values during early spring and early summer and low values during autumn and winter. Seawater particulate Mn peaked during winter and autumn, with a series of smaller peaks during spring and summer, whereas dissolved Mn2+ exhibited a marked single maximum during late-spring to early-summer, being low during the remainder of the year. Consequently, neither seawater particulate Mn nor dissolved Mn2+ concentrations explain the intra-annual variation of shell Mn/Ca ratios. A physiological control on shell Mn/Ca ratios is evident from the strong similarity and timing of the double-peaked intra-annual variations of Mn/Ca and shell growth rate (SGR), the latter corresponding to periods of increased metabolic activity (as indicated by respiration rate). It is thus likely that in M. edulis SGR influences shell Mn/Ca by altering the concentration or activity of Mn2+ within the extra-pallial fluid (EPF), by changing the flux of Mn into or the proportion of protein bound Mn within the EPF. By linking shell Mn/Ca ratios to the endogenous and environmental factors that determine growth and metabolic activity, this study helps to explain the lack of a consistent relationship between shell Mn/Ca in marine bivalve shell calcite and seawater particulate and dissolved Mn2+ concentrations. The use of Mn content from M. edulis

  19. Ocean acidification at high latitudes: potential effects on functioning of the Antarctic bivalve Laternula elliptica.

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    Vonda Cummings

    Full Text Available Ocean acidification is a well recognised threat to marine ecosystems. High latitude regions are predicted to be particularly affected due to cold waters and naturally low carbonate saturation levels. This is of concern for organisms utilising calcium carbonate (CaCO(3 to generate shells or skeletons. Studies of potential effects of future levels of pCO(2 on high latitude calcifiers are at present limited, and there is little understanding of their potential to acclimate to these changes. We describe a laboratory experiment to compare physiological and metabolic responses of a key benthic bivalve, Laternula elliptica, at pCO(2 levels of their natural environment (430 µatm, pH 7.99; based on field measurements with those predicted for 2100 (735 µatm, pH 7.78 and glacial levels (187 µatm, pH 8.32. Adult L. elliptica basal metabolism (oxygen consumption rates and heat shock protein HSP70 gene expression levels increased in response both to lowering and elevation of pH. Expression of chitin synthase (CHS, a key enzyme involved in synthesis of bivalve shells, was significantly up-regulated in individuals at pH 7.78, indicating L. elliptica were working harder to calcify in seawater undersaturated in aragonite (Ω(Ar = 0.71, the CaCO(3 polymorph of which their shells are comprised. The different response variables were influenced by pH in differing ways, highlighting the importance of assessing a variety of factors to determine the likely impact of pH change. In combination, the results indicate a negative effect of ocean acidification on whole-organism functioning of L. elliptica over relatively short terms (weeks-months that may be energetically difficult to maintain over longer time periods. Importantly, however, the observed changes in L. elliptica CHS gene expression provides evidence for biological control over the shell formation process, which may enable some degree of adaptation or acclimation to future ocean acidification scenarios.

  20. Anatomical study on Myoforceps aristatus, an invasive boring bivalve in S.E. Brazilian coast (Mytilidae

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    Luiz Ricardo L. Simone

    2006-01-01

    Full Text Available The bivalve Myoforceps aristatus (Dillwyn, 1817, also known as Lithophaga aristata, have been recently collected in the coasts of Rio de Janeiro and São Paulo, Brazil; a species that bores shells of other mollusks. This occurrence has been interpreted as an invasion of this species, originally from the Caribbean. The distinguishing character of the species is the posterior extensions of the shell crossing with each other. Because specimens with this character have also been collected in the Pacific Ocean, they all have been considered a single species. However, it is possible that more than one species may be involved in such worldwide distribution. With the objective of providing full information based on Atlantic specimens, a complete anatomical description is provided, which can be used in comparative studies with specimens from other oceans. Additional distinctive features of M. aristatus are the complexity of the incurrent siphon, the kidney opening widely into the supra-branchial chamber (instead of via a nephropore, and the multi-lobed auricle.O bivalve Myoforceps aristatus (Dillwyn, 1817, também conhecido como Lithophaga aristata, tem sido recentemente coletado nas costas do Rio de Janeiro e São Paulo, Brasil; uma espécie que perfura conchas de outros moluscos. Esta ocorrência está sendo interpretada como uma invasão de uma espécie originada do Caribe. O caráter distintivo da espécie é a região posterior da concha, com extensões que se cruzam. Como espécimes com esta característica também têm sido coletados no oceano Pacífico, eles tem sido considerados como pertencentes à mesma espécie. Entretanto, é possível que mais de uma espécie possam estar envolvidas nesta suposta distribuição mundial. Com o objetivo de fornecer informação completa baseada em material do Atlântico, uma descrição anatômica completa é dada, a qual pode ser usada em estudos comparativos com espécimes de outros oceanos. As caracter

  1. Parasites of economically important bivalves from the southern coast of Bahia State, Brazil Parasitos de bivalves de interesse econômico no Litoral Sul do Estado da Bahia, Brasil

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    Gabriela Calvi Zeidan

    2012-12-01

    Full Text Available This study investigated the parasites of three commercially important bivalve species (Crassostrea rhizophorae, Mytella guyanensis and Lucina pectinata from the southern coast of Bahia, Brazil. A total of 540 specimens were collected in August 2009 and February 2010, at three localities. The bivalve specimens were measured on their longest axis, opened, and macroscopically examined for the presence of parasites or signs of disease. They were then fixed in Davidson' solution and subjected to routine histological processing, with paraffin embedding and H&E staining; next, the specimens were examined under a light microscope. No parasites were observed associated with L. pectinata. Rickettsia-like organisms (RLOs, Sphenophrya sp. (Ciliophora, Nematopsis sp. (Apicomplexa, Urastoma sp. (Turbellaria and Bucephalus sp. (Digenea were observed in both C. rhizophorae and M. guyanensis, as well as Ancistrocoma sp. (Ciliophora and Tylocephalum sp. (Cestoda in the former. A high prevalence of Nematopsis sp. was seen, but caused no apparent damage to the host. Bucephalus sp. caused the destruction of tissues, with castration, but showed low prevalence. The other parasites occurred in low prevalence and intensity, without causing significant damage.Neste estudo foram investigados os parasitos de três espécies de bivalves de interesse econômico (Crassostrea rhizophorae, Mytella guyanensis e Lucina pectinata da Bahia. Foram analisados 540 exemplares, obtidos em duas coletas (agosto-2009 e fevereiro-2010, em três localidades. Os bivalves foram medidos quanto ao seu maior eixo, abertos e examinados macroscopicamente quanto à presença de parasitos ou sinais de enfermidades. Depois disso, foram fixados em solução de Davidson e processados por rotina de histologia, com inclusão em parafina e coloração com H&E. O material foi examinado ao microscópio de luz. Nenhum parasito esteve associado a L. pectinata. Bactérias do tipo RLOs (organismos assemelhados a

  2. Marine Bivalve Mollusks As Possible Indicators of Multidrug-Resistant Escherichia coli and Other Species of the Enterobacteriaceae Family

    Science.gov (United States)

    Grevskott, Didrik H.; Svanevik, Cecilie S.; Sunde, Marianne; Wester, Astrid L.; Lunestad, Bjørn T.

    2017-01-01

    The mechanisms for the development and spread of antibacterial resistance (ABR) in bacteria residing in environmental compartments, including the marine environment, are far from understood. The objective of this study was to examine the ABR rates in Escherichia coli and other Enterobacteriaceae isolates obtained from marine bivalve mollusks collected along the Norwegian coast during a period from October 2014 to November 2015. A total of 549 bivalve samples were examined by a five times three tube most probable number method for enumeration of E. coli in bivalves resulting in 199 isolates from the positive samples. These isolates were identified by biochemical reactions and matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry, showing that 90% were E. coli, while the remaining were species within the genera Klebsiella, Citrobacter, and Enterobacter. All 199 isolates recovered were susceptibility tested following the European Committee on Antimicrobial Susceptibility Testing disk diffusion method. In total, 75 of 199 (38%) isolates showed resistance to at least one antibacterial agent, while multidrug-resistance were seen in 9 (5%) isolates. One isolate conferred resistance toward 15 antibacterial agents. Among the 75 resistant isolates, resistance toward extended-spectrum penicillins (83%), aminoglycosides (16%), trimethoprim (13%), sulfonamides (11%), tetracyclines (8%), third-generation cephalosporins (7%), amphenicols (5%), nitrofurans (5%), and quinolones (5%), were observed. Whole-genome sequencing on a selection of 10 E. coli isolates identified the genes responsible for resistance, including blaCTX-M genes. To indicate the potential for horizontal gene transfer, conjugation experiments were performed on the same selected isolates. Conjugative transfer of resistance was observed for six of the 10 E. coli isolates. In order to compare E. coli isolates from bivalves with clinical strains, multiple-locus variable number tandem repeats

  3. Comparative analysis of morphometric characteristics of bivalves Anodonta piscinalis from the reservoirs of techa cascade of Mayak Production Association

    Energy Technology Data Exchange (ETDEWEB)

    Yegoreichenkov, E.; Pryakhin, E.; Akleyev, A. [Urals Research Center for Radiation Medicine - URCRM (Russian Federation)

    2014-07-01

    The reservoirs R-11, R-10 and R-4 of the Techa cascade (Chelyabinsk region) are used as low-active radioactive wastes storages, and are separated from open hydrographical network by a system of dams and by-pass channels. The values of specific activity of radionuclides in water and bottom sediments increases in the row: R-11, R-10, R-4, and at the same time the dose rate for zoo-benthos is increased on an order from reservoir to reservoir. Bivalves, which are obligate filter feeders and produce a significant part of water community biomass, are an important part of energy and matter transformation chain inside the hydro-biocenosis. Among this group of animals, the Anodonta piscinalis, a massive bivalve, takes the most part in biomass of Techa reservoirs cascade. Several studies show that in polluted environment the shell morphology changes are possible: the ratio of most morphometric values changes; the level of fluctuated asymmetry and shell polymorphism increases. For morphological studies of bivalves populations, 34 specimens of Anodonta were taken from R-11, 43 specimens from R-10 and 4 specimens from R-4. The specimens selection was arranged in May 2013, using hydro-biological drag. The shell shape was analyzed using TPS DIG software. Besides the measurements of maximal shell length, shell height, and the distance between shell's top and maximally distant point of front edge of the shell were measured. The ratio between the length and the height of the shell, between the length and the distance from the top to the front edge were calculated. The data analysis was arranged using R statistics. As a result of the data analysis the significant difference between shell's length to height ratios were registered between populations of R-4 and R-10 (p = 0.002). The ratio of maximal length of the shell to the distance from the top to the front edge also significantly differs between the animals of the R-4 and R-10 reservoirs (?= 0.03). Between the animals of

  4. Purification and characterization of an N-acetylglucosamine specific lectin from marine bivalve Macoma birmanica.

    Science.gov (United States)

    Adhya, Mausumi; Singha, Biswajit; Chatterjee, Bishnu P

    2009-07-01

    A calcium independent lectin of molecular mass 47kDa was isolated from the foot muscle of marine bivalve Macoma birmanica by ammonium sulphate precipitation followed by affinity chromatography on immobilized GlcNAc column and designated as M. birmanica agglutinin (MBA). The lectin agglutinated rabbit erythrocytes strongly compared to human erythrocytes over a wide pH range from 5 to 9 and up to 50 degrees C. MBA is a glycoprotein and consists of 7.63% sugar. Among the tested sugars for analysis of carbohydrate recognition properties, Me-betaGlcNAc was the most potent inhibitor followed by Me-alphaMan. Enzyme linked solid phase assay revealed that MBA interacted well with complex type N-linked glycans and moderately to high mannose type N-linked glycans. Fluorescence study of MBA indicated that tryptophan was present in a non-hydrophobic region and its binding to GlcNAc was neither quenched nor altered lambda(max) position. The denaturation of MBA induced by urea was a reversible process and urea could not significantly change the Trp environment. MBA interacted with both Gram-positive and Gram-negative bacteria by recognizing their surface exposed GlcNAc containing antigens.

  5. Irradiated bivalve mollusks: Use of EPR spectroscopy for identification and dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Alberti, Angelo, E-mail: aalberti@isof.cnr.it [CNR-ISOF, Area della Ricerca di Bologna, Via P. Gobetti 101, Bologna I-40129 (Italy); Chiaravalle, Eugenio [Istituto Zooprofilattico Sperimentale della Puglia e Basilicata, Via Manfredonia 20, Foggia I-71100 (Italy); Fuochi, Piergiorgio; Macciantelli, Dante [CNR-ISOF, Area della Ricerca di Bologna, Via P. Gobetti 101, Bologna I-40129 (Italy); Mangiacotti, Michele, E-mail: michelemangiacotti@libero.it [Istituto Zooprofilattico Sperimentale della Puglia e Basilicata, Via Manfredonia 20, Foggia I-71100 (Italy); Marchesani, Giuliana [Istituto Zooprofilattico Sperimentale della Puglia e Basilicata, Via Manfredonia 20, Foggia I-71100 (Italy); Plescia, Elena [CNR-ISOF, Area della Ricerca di Bologna, Via P. Gobetti 101, Bologna I-40129 (Italy)

    2011-12-15

    High energy radiation treatment of foodstuff for microbial control and shelf-life extension is being used in many countries. However, for consumer protection and information, the European Union has adopted the Directives 1999/2/EC and 1999/3/EC to harmonize the rules concerning the treatment and trade of irradiated foods in EU countries. Among the validated methods to detect irradiated foods the EU directives also include Electron Paramagnetic Resonance (EPR/ESR) spectroscopy. We describe herein the use of EPR for identification of four species of bivalve mollusks, i.e. brown Venus shells (Callista chione), clams (Tapes semidecussatus), mussels (Mytilus galloprovincialis) and oysters (Ostrea edulis) irradiated with {sup 60}Co {gamma}-rays. EPR could definitely identify irradiated seashells due to the presence of long-lived free radicals, primarily CO{sub 2}{sup -}, CO{sub 3}{sup 3-}, SO{sub 2}{sup -} and SO{sub 3}{sup -} radical anions. The presence of other organic free radicals, believed to originate from conchiolin, a scleroprotein present in the shells, was also ascertained. The use of one of these radicals as a marker for irradiation of brown Venus shells and clams can be envisaged. We also propose a dosimetric protocol for the reconstruction of the administered dose in irradiated oysters. - Highlights: > EPR spectroscopy is confirmed a valuable identification tool for irradiated mollusks. > A conchiolin-derived radical can be used as irradiation marker for some mollusks. > A reliable protocol is outlined for dose reconstruction of irradiated oysters.

  6. Marine bivalve geochemistry and shell ultrastructure from modern low pH environments

    Directory of Open Access Journals (Sweden)

    S. Hahn

    2011-10-01

    Full Text Available Bivalve shells can provide excellent archives of past environmental change but have not been used to interpret ocean acidification events. We investigated carbon, oxygen and trace element records from different shell layers in the mussels Mytilus galloprovincialis (from the Mediterranean and M. edulis (from the Wadden Sea combined with detailed investigations of the shell ultrastructure. Mussels from the harbour of Ischia (Mediterranean, Italy were transplanted and grown in water with mean pHT 7.3 and mean pHT 8.1 near CO2 vents on the east coast of the island of Ischia. The shells of transplanted mussels were compared with M. edulis collected at pH ~8.2 from Sylt (German Wadden Sea. Most prominently, the shells recorded the shock of transplantation, both in their shell ultrastructure, textural and geochemical record. Shell calcite, precipitated subsequently under acidified seawater responded to the pH gradient by an in part disturbed ultrastructure. Geochemical data from all test sites show a strong metabolic effect that exceeds the influence of the low-pH environment. These field experiments showed that care is needed when interpreting potential ocean acidification signals because various parameters affect shell chemistry and ultrastructure. Besides metabolic processes, seawater pH, factors such as salinity, water temperature, food availability and population density all affect the biogenic carbonate shell archive.

  7. The evolutionary origins of the southern ocean Philobryid bivalves: hidden biodiversity, ancient persistence.

    Directory of Open Access Journals (Sweden)

    Jennifer A Jackson

    Full Text Available Philobryids (Bivalvia: Arcoida are one of the most speciose marine bivalve families in the Southern Ocean and are common throughout the Southern Hemisphere. Considering this diversity and their brooding reproductive mode (limiting long-distance dispersal, this family may have been present in the Southern Ocean since its inception. However Philobrya and Adacnarca appear only in the Quaternary fossil record of the Antarctic, suggesting a much more recent incursion. Molecular dating provides an independent means of measuring the time of origin and radiation of this poorly known group. Here we present the first combined molecular and morphological investigation of the Philobryidae in the Southern Ocean. Two nuclear loci (18S and 28S were amplified from 35 Southern Ocean Adacnarca and Philobrya specimens, with a combined sequence length of 2,282 base pairs (bp. Adacnarca specimens (A. nitens and A. limopsoides were resolved as a strongly supported monophyletic group. Genus Philobrya fell into two strongly supported groups ('sublaevis' and 'magellanica/wandelensis', paraphyletic with Adacnarca. The A. nitens species complex is identified as at least seven morpho-species through morphological and genetic analysis of taxon clustering. Phylogenetic analyses resolve Philobryidae as a strongly supported monophyletic clade and sister taxon to the Limopsidae, as anticipated by their classification into the superfamily Limopsoidea. Bayesian relaxed clock analyses of divergence times suggest that genus Adacnarca radiated in the Southern Ocean from the Early Paleogene, while P. sublaevis and P. wandelensis clades radiated in the late Miocene, following the formation of the Antarctic Circumpolar Current.

  8. Influence of acid-soluble proteins from bivalve Siliqua radiata ligaments on calcium carbonate crystal growth

    Science.gov (United States)

    Huang, Zeng-Qiong; Zhang, Gang-Sheng

    2016-08-01

    In vitro biomimetic synthesis of calcium carbonate (CaCO3) in the presence of shell proteins is a heavily researched topic in biomineralization. However, little is known regarding the function of bivalve ligament proteins in the growth of CaCO3 crystals. In this study, using fibrous protein K58 from Siliqua radiata ligaments or coverslips as substrates, we report the results of our study of CaCO3 precipitation in the presence or absence of acid-soluble proteins (ASP) from inner ligament layers. ASP can disturb the controlling function of K58 or a coverslip on the crystalline phase, resulting in the formation of aragonite, calcite, and vaterite. In addition, we identified the following four primary components from ASP by mass spectroscopy: alkaline phosphatase (ALP), ABC transporter, keratin type II cytoskeletal 1 (KRT 1), and phosphate ABC transporter, phosphate-binding protein (PstS). Further analysis revealed that the first three proteins and especially ALP, which is important in bone mineralisation, could affect the polymorphism and morphology of CaCO3 crystals by trapping calcium ions in their domains. Our results indicate that ALP may play an important role in the formation of aragonite in S. radiata ligaments. This paper may facilitate our understanding of the biomineralization process.

  9. The Shell of the Invasive Bivalve Species Dreissena polymorpha: Biochemical, Elemental and Textural Investigations

    Science.gov (United States)

    Broussard, Cédric; Catherinet, Bastien; Plasseraud, Laurent; Alcaraz, Gérard; Bundeleva, Irina; Marin, Frédéric

    2016-01-01

    The zebra mussel Dreissena polymorpha is a well-established invasive model organism. Although extensively used in environmental sciences, virtually nothing is known of the molecular process of its shell calcification. By describing the microstructure, geochemistry and biochemistry/proteomics of the shell, the present study aims at promoting this species as a model organism in biomineralization studies, in order to establish a bridge with ecotoxicology, while sketching evolutionary conclusions. The shell of D. polymorpha exhibits the classical crossed-lamellar/complex crossed lamellar combination found in several heterodont bivalves, in addition to an external thin layer, the characteristics of which differ from what was described in earlier publication. We show that the shell selectively concentrates some heavy metals, in particular uranium, which predisposes D. polymorpha to local bioremediation of this pollutant. We establish the biochemical signature of the shell matrix, demonstrating that it interacts with the in vitro precipitation of calcium carbonate and inhibits calcium carbonate crystal formation, but these two properties are not strongly expressed. This matrix, although overall weakly glycosylated, contains a set of putatively calcium-binding proteins and a set of acidic sulphated proteins. 2D-gels reveal more than fifty proteins, twenty of which we identify by MS-MS analysis. We tentatively link the shell protein profile of D. polymorpha and the peculiar recent evolution of this invasive species of Ponto-Caspian origin, which has spread all across Europe in the last three centuries. PMID:27213644

  10. New mitochondrial and nuclear primers for the Mediterranean marine bivalve Pinna nobilis

    Directory of Open Access Journals (Sweden)

    D. SANNA

    2014-07-01

    Full Text Available Pinna nobilis is the largest endemic Mediterranean marine bivalve. During past centuries, various human activities led to the regression of its populations. As a consequence of stringent standards of protection, demographic expansions are currently reported in many sites. We designed a set of four mitochondrial- and two nuclear- specific PCR-primers with the aim to provide molecular tools to gather new insights into the genetic variability of this species. A total of 54 specimens were sampled from 25 Mediterranean localities in order to evaluate the level of polymorphism of these markers in P. nobilis. The most variable molecular markers identified were the mitochondrial Cytochrome c Oxidase subunit I (COI, NADH dehydrogenase subunit 3 (nad3, and 16S ribosomal DNA (16S. Positive results, in terms of good amplifications and scorable sequences, were also obtained in the co-generic Pinna rudis. The molecular markers identified in this study, and the PCR-protocols provided, represent a useful tool for future researches devoted to infer the genetic variability of P. nobilis populations thus allowing the development of effective conservation measures.

  11. The Shell of the Invasive Bivalve Species Dreissena polymorpha: Biochemical, Elemental and Textural Investigations.

    Directory of Open Access Journals (Sweden)

    Françoise Immel

    Full Text Available The zebra mussel Dreissena polymorpha is a well-established invasive model organism. Although extensively used in environmental sciences, virtually nothing is known of the molecular process of its shell calcification. By describing the microstructure, geochemistry and biochemistry/proteomics of the shell, the present study aims at promoting this species as a model organism in biomineralization studies, in order to establish a bridge with ecotoxicology, while sketching evolutionary conclusions. The shell of D. polymorpha exhibits the classical crossed-lamellar/complex crossed lamellar combination found in several heterodont bivalves, in addition to an external thin layer, the characteristics of which differ from what was described in earlier publication. We show that the shell selectively concentrates some heavy metals, in particular uranium, which predisposes D. polymorpha to local bioremediation of this pollutant. We establish the biochemical signature of the shell matrix, demonstrating that it interacts with the in vitro precipitation of calcium carbonate and inhibits calcium carbonate crystal formation, but these two properties are not strongly expressed. This matrix, although overall weakly glycosylated, contains a set of putatively calcium-binding proteins and a set of acidic sulphated proteins. 2D-gels reveal more than fifty proteins, twenty of which we identify by MS-MS analysis. We tentatively link the shell protein profile of D. polymorpha and the peculiar recent evolution of this invasive species of Ponto-Caspian origin, which has spread all across Europe in the last three centuries.

  12. Habitat creation and biodiversity maintenance in mangrove forests: teredinid bivalves as ecosystem engineers.

    Science.gov (United States)

    Hendy, Ian W; Michie, Laura; Taylor, Ben W

    2014-01-01

    Substantial amounts of dead wood in the intertidal zone of mature mangrove forests are tunnelled by teredinid bivalves. When the tunnels are exposed, animals are able to use tunnels as refuges. In this study, the effect of teredinid tunnelling upon mangrove forest faunal diversity was investigated. Mangrove forests exposed to long emersion times had fewer teredinid tunnels in wood and wood not containing teredinid tunnels had very few species and abundance of animals. However, with a greater cross-sectional percentage surface area of teredinid tunnels, the numbers of species and abundance of animals was significantly higher. Temperatures within teredinid-attacked wood were significantly cooler compared with air temperatures, and animal abundance was greater in wood with cooler temperatures. Animals inside the tunnels within the wood may avoid desiccation by escaping the higher temperatures. Animals co-existing in teredinid tunnelled wood ranged from animals found in terrestrial ecosystems including centipedes, crickets and spiders, and animals found in subtidal marine ecosystems such as fish, octopods and polychaetes. There was also evidence of breeding within teredinid-attacked wood, as many juvenile individuals were found, and they may also benefit from the cooler wood temperatures. Teredinid tunnelled wood is a key low-tide refuge for cryptic animals, which would otherwise be exposed to fishes and birds, and higher external temperatures. This study provides evidence that teredinids are ecosystem engineers and also provides an example of a mechanism whereby mangrove forests support intertidal biodiversity and nurseries through the wood-boring activity of teredinids.

  13. Irradiated bivalve mollusks: Use of EPR spectroscopy for identification and dosimetry

    Science.gov (United States)

    Alberti, Angelo; Chiaravalle, Eugenio; Fuochi, Piergiorgio; Macciantelli, Dante; Mangiacotti, Michele; Marchesani, Giuliana; Plescia, Elena

    2011-12-01

    High energy radiation treatment of foodstuff for microbial control and shelf-life extension is being used in many countries. However, for consumer protection and information, the European Union has adopted the Directives 1999/2/EC and 1999/3/EC to harmonize the rules concerning the treatment and trade of irradiated foods in EU countries. Among the validated methods to detect irradiated foods the EU directives also include Electron Paramagnetic Resonance (EPR/ESR) spectroscopy.We describe herein the use of EPR for identification of four species of bivalve mollusks, i.e. brown Venus shells (Callista chione), clams (Tapes semidecussatus), mussels (Mytilus galloprovincialis) and oysters (Ostrea edulis) irradiated with 60Co γ-rays. EPR could definitely identify irradiated seashells due to the presence of long-lived free radicals, primarily CO2-, CO33-, SO2- and SO3- radical anions. The presence of other organic free radicals, believed to originate from conchiolin, a scleroprotein present in the shells, was also ascertained. The use of one of these radicals as a marker for irradiation of brown Venus shells and clams can be envisaged. We also propose a dosimetric protocol for the reconstruction of the administered dose in irradiated oysters.

  14. Zachsia zenkewitschi (Teredinidae), a Rare and Unusual Seagrass Boring Bivalve Revisited and Redescribed

    Science.gov (United States)

    Shipway, J. R.; O’Connor, R.; Stein, D.; Cragg, S. M.; Korshunova, T.; Martynov, A.; Haga, T.; Distel, D. L.

    2016-01-01

    The sea-grass borer Zachsia zenkewitschi belongs to a group of economically and ecologically important bivalves, commonly referred to as shipworms. The sole recognized representative of the genus Zachsia, this species displays an unusual life history and reproductive strategy that is now understood to include: environmental sex determination of free swimming larvae, extreme sexual and size dimorphism between males and females, internal fertilization, maintenance of often large harems of male dwarfs within a specialized cavity of the female mantle, and complex maternal care of larvae in specialized brood pouches within the gill. It is also the only shipworm species known to burrow in sea grass rhizomes rather than terrestrial wood. Although Z. zenkewitschi is rare and little studied, understanding of its biology and anatomy has evolved substantially, rendering some aspects of its original description inaccurate. Moreover, no existing type specimens are known for this species. In light of these facts, we designate a neotype from among specimens recently collected at the type location, and undertake a re-description of this species, accounting for recent reinterpretation of its life history and functional anatomy. PMID:27171209

  15. The bivalve Anopaea (Inoceramidae) from the Upper Jurassic-lowermost Cretaceous of Mexico

    Science.gov (United States)

    Zell, Patrick; Crame, J. Alistair; Stinnesbeck, Wolfgang; Beckmann, Seija

    2015-07-01

    In Mexico, the Upper Jurassic to lowermost Cretaceous La Casita and coeval La Caja and La Pimienta formations are well-known for their abundant and well-preserved marine vertebrates and invertebrates. The latter include conspicuous inoceramid bivalves of the genus Anopaea not formally described previously from Mexico. Anopaea bassei (Lecolle de Cantú, 1967), Anopaea cf. stoliczkai (Holdhaus, 1913), Anopaea cf. callistoensis Crame and Kelly, 1995 and Anopaea sp. are rare constituents in distinctive Tithonian-lower Berriasian levels of the La Caja Formation and one Tithonian horizon of the La Pimienta Formation. Anopaea bassei was previously documented from the Tithonian of central Mexico and Cuba, while most other members of Anopaea described here are only known from southern high latitudes. The Mexican assemblage also includes taxa which closely resemble Anopaea stoliczkai from the Tithonian of India, Indonesia and the Antarctic Peninsula, and Anopaea callistoensis from the late Tithonian to ?early Berriasian of the Antarctic Peninsula. Our new data expand the palaeogeographical distribution of the high latitude Anopaea to the Gulf of Mexico region and substantiate faunal exchange, in the Late Jurassic-earliest Cretaceous, between Mexico and the Antarctic Realm.

  16. Aspartic acid racemization dating of Holocene brachiopods and bivalves from the southern Brazilian shelf, South Atlantic

    Science.gov (United States)

    Barbour Wood, Susan L.; Krause, Richard A.; Kowalewski, Michał; Wehmiller, John; Simões, Marcello G.

    2006-09-01

    The extent of racemization of aspartic acid (Asp) has been used to estimate the ages of 9 shells of the epifaunal calcitic brachiopod Bouchardia rosea and 9 shells of the infaunal aragonitic bivalve Semele casali. Both taxa were collected concurrently from the same sites at depths of 10 m and 30 m off the coast of Brazil. Asp D/L values show an excellent correlation with radiocarbon age at both sites and for both taxa ( r2Site 9 B. rosea = 0.97, r2Site 1 B. rosea = 0.997, r2Site 9 S. casali = 0.9998, r2Site 1 S. casali = 0.93). The Asp ratios plotted against reservoir-corrected AMS radiocarbon ages over the time span of multiple millennia can thus be used to develop reliable and precise geochronologies not only for aragonitic mollusks (widely used for dating previously), but also for calcitic brachiopods. At each collection site, Bouchardia specimens display consistently higher D/L values than specimens of Semele. Thermal differences between sites are also notable and in agreement with theoretical expectations, as extents of racemization for both taxa are greater at the warmer, shallower site than at the cooler, deeper one. In late Holocene marine settings, concurrent time series of aragonitic and calcitic shells can be assembled using Asp racemization dating, and parallel multi-centennial to multi-millennial records can be developed simultaneously for multiple biomineral systems.

  17. Into the deep: a phylogenetic approach to the bivalve subclass Protobranchia.

    Science.gov (United States)

    Sharma, Prashant P; Zardus, John D; Boyle, Elizabeth E; González, Vanessa L; Jennings, Robert M; McIntyre, Erin; Wheeler, Ward C; Etter, Ron J; Giribet, Gonzalo

    2013-10-01

    A molecular phylogeny of Protobranchia, the subclass of bivalve mollusks sister to the remaining Bivalvia, has long proven elusive, because many constituent lineages are deep-sea endemics, which creates methodological challenges for collecting and preserving genetic material. We obtained 74 representatives of all 12 extant protobranch families and investigated the internal phylogeny of this group using sequence data from five molecular loci (16S rRNA, 18S rRNA, 28S rRNA, cytochrome c oxidase subunit I, and histone H3). Model-based and dynamic homology parsimony approaches to phylogenetic reconstruction unanimously supported four major clades of Protobranchia, irrespective of treatment of hypervariable regions in the nuclear ribosomal genes 18S rRNA and 28S rRNA. These four clades correspond to the superfamilies Nuculoidea (excluding Sareptidae), Nuculanoidea (including Sareptidae), Solemyoidea, and Manzanelloidea. Salient aspects of the phylogeny include (1) support for the placement of the family Sareptidae with Nuculanoidea; (2) the non-monophyly of the order Solemyida (Solemyidae+Nucinellidae); (3) and the non-monophyly of most nuculoid and nuculanoid genera and families. In light of this first family-level phylogeny of Protobranchia, we present a revised classification of the group. Estimation of divergence times in concert with analyses of diversification rates demonstrate the signature of the end-Permian mass extinction in the phylogeny of extant protobranchs.

  18. Marine bivalves as high-temporal-resolution paleoclimate proxies: a study in the northern Peruvian littoral

    Science.gov (United States)

    Houk, S. D.; Maasch, K. A.; Sandweiss, D. H.

    2003-04-01

    This study indicates the need for further methodological development of marine bivalves as high-temporal-resolution sea surface temperature (SST) proxies. Daily incremental growth of the intertidal species Chione subrugosa as well as subdaily growth of the mangrove swamp species Anadara tuberculosa and the subtidal species Trachycardium procerum accommodate the temporal correlation of stable oxygen isotope samples extracted from these aragonite shells. Incremental growth of modern comparative specimens and those from the Siches (7420 cal yr B.P. to 5650 cal yr B.P.) and Ostra Base Camp (6660 cal yr B.P.) shell middens on the north coast of Peru was used to constrain δ18O data with monthly resolution. Modern A. tuberculosa, C. subrugosa, and T. procerum provide discrete δ18O time series two to four years in duration, which were correlated with mean monthly SST and salinity in order to test the accuracy of growth increment counts. The δ18O time series constructed from the ancient shells float within a date range provided by radiocarbon-dated contexts from which the shells were excavated. Results suggest that stable oxygen isotope ratios in subtidal species, beyond the influence of local salinity and temperature variations or subaerial exposure at low tide, significantly covary with ocean surface temperatures. Further synthesis of growth increment and stable isotope analyses, including specific calibration of an oxygen isotope ratio-temperature function, might establish a quantitative description of interseasonal and interannual SST variability along the Middle Holocene coast of Peru.

  19. Marine bivalve geochemistry and shell ultrastructure from modern low pH environments

    Science.gov (United States)

    Hahn, S.; Rodolfo-Metalpa, R.; Griesshaber, E.; Schmahl, W. W.; Buhl, D.; Hall-Spencer, J. M.; Baggini, C.; Fehr, K. T.; Immenhauser, A.

    2011-10-01

    Bivalve shells can provide excellent archives of past environmental change but have not been used to interpret ocean acidification events. We investigated carbon, oxygen and trace element records from different shell layers in the mussels Mytilus galloprovincialis (from the Mediterranean) and M. edulis (from the Wadden Sea) combined with detailed investigations of the shell ultrastructure. Mussels from the harbour of Ischia (Mediterranean, Italy) were transplanted and grown in water with mean pHT 7.3 and mean pHT 8.1 near CO2 vents on the east coast of the island of Ischia. The shells of transplanted mussels were compared with M. edulis collected at pH ~8.2 from Sylt (German Wadden Sea). Most prominently, the shells recorded the shock of transplantation, both in their shell ultrastructure, textural and geochemical record. Shell calcite, precipitated subsequently under acidified seawater responded to the pH gradient by an in part disturbed ultrastructure. Geochemical data from all test sites show a strong metabolic effect that exceeds the influence of the low-pH environment. These field experiments showed that care is needed when interpreting potential ocean acidification signals because various parameters affect shell chemistry and ultrastructure. Besides metabolic processes, seawater pH, factors such as salinity, water temperature, food availability and population density all affect the biogenic carbonate shell archive.

  20. Immune-related genes in gastropods and bivalves: a comparative overview

    Directory of Open Access Journals (Sweden)

    M Gerdol

    2017-04-01

    Full Text Available The biological diversity of molluscs and their adaptation to highly diverse environments offer a unique opportunity for studying the evolution of the innate immune system in invertebrates. This review provides an updated account about the progresses made over the past few years in the study of the molecular players involved in the recognition of pathogen associated molecular patters (PAMPs, in the transduction of immune signaling and in the elimination of potentially pathogenic microbes in gastropod and bivalve molluscs. A major focus will be put on the differences and peculiarities of the molecular immune system of the two major molluscan classes, which have developed specific adaptations to cope with diverse living environments, pathogenic and nonpathogenic microbes over the course of several hundred million years of independent evolution. Intriguing but still poorly understood aspects, such as antiviral response and immune priming, will be also explored, highlighting the present challenges and opportunities connected to the application of modern genomics techniques to the study of the immune system in these fascinating metazoans.

  1. Marine Bacteria with antimicrobials capacity isolated from cultures of bivalve mollusks

    Directory of Open Access Journals (Sweden)

    Fabiola Pellon

    2014-06-01

    Full Text Available Microorganisms have commonly been studied as producers of antibacterial substances; yet they are also considered producers of antifungic, antiviral, antiparasitic, citotoxics and inhibitory of other forms of cellular growth substances. This paper describes the isolation, inhibitory potential and phenotipic characterization of native bacterial strains associated to bivalve mollusks such as Argopecten purpuratus “concha de abanico” and Crassostrea gigas “ostra” in cultivation systems. From 345 marine strains collected, 20 strains were recovered that had the ability of inhibiting a wide spectrum of fish, mollusks and shellfish pathogenic bacteria; being the most sensitive pathogens Aeromonas sobria P-281, Aeromonas hydrophila ATCC 7966, Vibrio vulnificus ATCC 27562 and Vibrio parahaemolyticus ATCC 17803. The phenotipic characterization of this strains with inhibitory capacity allowed the identification of the following genera: Vibrio (40%, Aeromonas (15%, Flavobacterium (10%, Pseudomonas (5%, Moraxella (5%, Flexibacter (5%. A 20% could not be identified. The results suggest that the isolated bacteria could be used as probiotics agents for the biological control of pathogens from marine organisms of interest in mariculture.

  2. Structure and Classification of Haemocytes in the Bivalve Mollusc Meretrix meretrix

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yanyan; REN Sulian; WANG Dexiu; SONG Weibo

    2006-01-01

    Light and electron microscopic studies were carried out in order to characterize haemocytes in the bivalve mollusc Meretrix meretrix. According to nucleus and cytoplasm characters, four types of haemocytes were recognized: agranular haemocytes, lymphoid haemocyte, large granular and small granular haemocytes. Agranular hamocyte is the main cell type,accounting for 75%. It is agranular with rich organelles in cytoplasm, including mitochondria, golgi body and endoplasmic reticulum. Glycogen deposits were usually found in this cell type. The number of lymphoid haemocyte accounts for 1% -2%. This cell type is agranular and shows a high ratio of nucleus to cytoplasm. A few organelles were found. High electrondense granules with diameters of 0.2 - 0.5 μm and rich organelles were found in small granular haemocyte. The proportion of this cell type is about 15%. Rich granules of high electron-dense with diameters of 0.8- 2.4μm were found in large granular haemocyte. The proportion of this cell type is about 10%, and the quantity of organelles is the least.

  3. Vertical transmission of chemoautotrophic symbionts in the bivalve Solemya velum (Bivalvia: Protobranchia).

    Science.gov (United States)

    Krueger, D M; Gustafson, R G; Cavanaugh, C M

    1996-04-01

    Adults of the bivalve species Solemya velum live in symbiosis with chemoautotrophic bacteria in specialized gill bacteriocytes. The bacteria play an essential nutritional role in the mature association, fixing CO2 via the Calvin cycle with energy obtained through the oxidation of reduced sulfur compounds. To understand how the continuity of this partnership is maintained between host generations, we investigated the mode of symbiont transfer in S. velum. A diagnostic assay using the polymerase chain reaction and primers specific for the S. velum symbiont ribulose-1,5-bisphosphate carboxylase (RubisCO) gene consistently detected bacterial sequence in female gonad tissue, suggesting the presence of symbiont cells in host ovaries and a vertical mode of symbiont transmission from mother to offspring. Furthermore, intracellular bacteria were present in the developing gills of juveniles that had not yet hatched from the gelatinous capsule in which larval development occurs (11 days after fertilization). By 64 days postfertilization, the typical adult gill ultrastructure of alternating bacteriocytes and symbiont-free-intercalary cells was apparent. Knowledge about the mode of symbiont transfer in S. velum allows further study into the dynamics of host-symbiont interactions in chemoautotrophic associations.

  4. Congener-specific distribution and bioaccumulation of short-chain chlorinated paraffins in sediments and bivalves of the Bohai Sea, China.

    Science.gov (United States)

    Ma, Xindong; Chen, Chen; Zhang, Haijun; Gao, Yuan; Wang, Zhen; Yao, Ziwei; Chen, Jiping; Chen, Jingwen

    2014-02-15

    Short-chain chlorinated paraffins (SCCPs) are a new type of persistent organic pollutants that are of great environmental concern because of their wide distribution. In this study, surface sediments and bivalve samples were collected from the coastal area of the Bohai Sea in China. Total SCCP (ΣSCCP) concentrations in surface sediments and bivalves ranged from 97.4 ng g(-1) dry weight (dw) to 1756.7 ng g(-1) dw and 476.4-3269.5 ng g(-1) dw, respectively. C10-CPs and C11-CPs were the predominant homologue groups in all sediments and bivalves. Specific congener composition analysis and correspondence analysis indicated that the local SCCP source mainly came from CP-42 and CP-52 products, and riverine input had an important function. The biota-sediment accumulation factors of ΣSCCPs for bivalves ranged from 1.08 to 1.61, and a significant correlation indicated that the SCCP congener with higher chlorination degree was more likely to be accumulated in bivalves.

  5. Species composition, richness, and distribution of marine bivalve molluscs in Bahía de Mazatlán, México

    Science.gov (United States)

    Esqueda-González, María del Carmen; Ríos-Jara, Eduardo; Galván-Villa, Cristian Moises; Rodríguez-Zaragoza, Fabian Alejandro

    2014-01-01

    Abstract We describe the composition and distribution of bivalve molluscs from the sandy and rocky intertidal and the shallow subtidal environments of Bahía de Mazatlán, México. The bivalve fauna of the bay is represented by 89 living species in 28 families, including 37 new records and four range extensions: Lithophaga hastasia, Adula soleniformis, Mactrellona subalata, and Strigilla ervilia. The number of species increases from the upper (44) and lower intertidal (53) to the shallow subtidal (76), but only 11 (17%) have a wide distribution in the bay (i.e., found in all sampling sites and environments). The bivalve assemblages are composed of four main life forms: 27 epifaunal species, 26 infaunal, 16 semi-infaunal, and 20 endolithic. A taxonomic distinctness analysis identified the sampling sites and environments that contribute the most to the taxonomic diversity (species to suborder categories) of the bay. The present work increased significantly (31%) to 132 species previous inventories of bivalves of Bahía de Mazatlán. These species represent 34% of the bivalve diversity of the southern Golfo de California and approximately 15% of the Eastern Tropical Pacific region. PMID:24843252

  6. Species composition, richness, and distribution of marine bivalve molluscs in Bahía de Mazatlán, México

    Directory of Open Access Journals (Sweden)

    María del Carmen Esqueda-González

    2014-04-01

    Full Text Available We describe the composition and distribution of bivalve molluscs from the sandy and rocky intertidal and the shallow subtidal environments of Bahía de Mazatlán, México. The bivalve fauna of the bay is represented by 89 living species in 28 families, including 37 new records and four range extensions: Lithophaga hastasia, Adula soleniformis, Mactrellona subalata, and Strigilla ervilia. The number of species increases from the upper (44 and lower intertidal (53 to the shallow subtidal (76, but only 11 (17% have a wide distribution in the bay (i.e., found in all sampling sites and environments. The bivalve assemblages are composed of four main life forms: 27 epifaunal species, 26 infaunal, 16 semi-infaunal, and 20 endolithic. A taxonomic distinctness analysis identified the sampling sites and environments that contribute the most to the taxonomic diversity (species to suborder categories of the bay. The present work increased significantly (31% to 132 species previous inventories of bivalves of Bahía de Mazatlán. These species represent 34% of the bivalve diversity of the southern Golfo de California and approximately 15% of the Eastern Tropical Pacific region.

  7. Mg isotopes in biocarbonates: new insight into vital effects associated to echinoderms and bivalves calcification

    Science.gov (United States)

    Planchon, F.; Hermans, J.; Borremans, C.; Dubois, P.; Poulain, C.; Paulet, Y.; Andre, L.

    2007-12-01

    Mg isotopes can be helpful tracers to reveal the fundamental pathways of Mg incorporation during biomineralisation. We report in this study a detailed characterisation of the Mg isotopic signatures of different biominerals: high magnesium calcitic skeletons of selected echinoderms (sea urchins and starfish) and low magnesium aragonitic shells of a bivalve species (clam). State of the art analytical procedures were applied including sample purification step followed by high precision measurements using MC-ICP-MS (Nu instrument) in dry plasma conditions. 26Mg/24Mg and 25Mg/24Mg are expressed as per mil deviations from the DSM3 (Dead Sea Metal 3) reference standard in delta notation (d26Mg and d25Mg). For echinoderms, we considered: (a) adult specimens of six starfish species (Asteria r., Marthasterias g., Anseropoda p., Asterina g., Echinaster s. and Henricia o.), sampled in Brittany (France); (b) a sea urchin species (Paracentrotus lividus) with field samples (Mediterranean Sea, Marseille, France) and culture specimen under T and S controlled conditions. In vivo endoskeletons display negative, but different d26Mg values of -3.06 for starfish (with uniform interspecies signatures) and -2.65 for sea urchin. Relative to seawater signature (-0.82), all echinoderms favour the incorporation of light isotopes during biocalcification. The d26Mg depletion is lower than theoretically expected from a inorganic calcite precipitation from seawater (at -3.5). These differences suggest that on its route from seawater to the shell, Mg isotopes are partly biologically fractionationated through "vital effects" leaving heavier Mg isotopic signatures. Taken into account that calcification in echinoderms is an intra- cellular process involving transient amorphous calcium carbonate (ACC) phase, the observed bio-fractionation factors can be related to: (1) changes in the isotopic composition of the precipitating intracellular fluids due to active pumping in and out of the cell; (2) a

  8. Mixed function oxygenases and xenobiotic detoxication/toxication systems in bivalve molluscs

    Science.gov (United States)

    Moore, M. N.; Livingstone, D. R.; Donkin, P.; Bayne, B. L.; Widdows, J.; Lowe, D. M.

    1980-03-01

    Components of a xenobiotic detoxication/toxication system involving mixed function oxygenases are present in Mytilus edulis. Our paper critically reviews the recent literature on this topic which reported the apparent absence of such a system in bivalve molluscs and attempts to reconcile this viewpoint with our own findings on NADPH neotetrazolium reductase, glucose-6-phosphate dehydrogenase, aldrin epoxidation and other reports of the presence of mixed function oxygenases. New experimental data are presented which indicate that some elements of the detoxication/toxication system in M. edulis can be induced by aromatic hydrocarbons derived from crude oil. This includes a brief review of the results of long-term experiments in which mussels were exposed to low concentrations of the water accommodated fraction of North Sea crude oil (7.7-68 µg 1-1) in which general stress responses such as reduced physiological scope for growth, cytotoxic damage to lysosomal integrity and cellular damage are considered as characteristics of the general stress syndrome induced by the toxic action of the xenobiotics. In addition, induction in the blood cells of microsomal NADPH neotetrazolium reductase (associated with mixed function oxygenases) and the NADPH generating enzyme glucose-6-phosphate dehydrogenase are considered to be specific biological responses to the presence of aromatic hydrocarbons. The consequences of this detoxication/toxication system for Mytilus edulis are discussed in terms of the formation of toxic electrophilic intermediate metabolites which are highly reactive and can combine with DNA, RNA and proteins with subsequent damage to these cellular constituents. Implications for neoplasms associated with the blood cells are also discussed. Finally, in view of the increased use of mussel species in pollutant monitoring programmes, the induction phenomenon which is associated with microsomal enzymes in the blood cells is considered as a possible tool for the

  9. Molluscs for Sale: Assessment of Freshwater Gastropods and Bivalves in the Ornamental Pet Trade

    Science.gov (United States)

    Tan, Siong Kiat; Wong, Wing Hing; Meier, Rudolf; Chan, Sow-Yan; Tan, Heok Hui; Yeo, Darren C. J.

    2016-01-01

    The ornamental pet trade is often considered a key culprit for conservation problems such as the introduction of invasive species (including infectious diseases) and overharvesting of rare species. Here, we present the first assessment of the biodiversity of freshwater molluscs in the ornamental pet trade in Singapore, one of the most important global hubs of the ornamental aquarium trade, and discuss associated conservation concerns. We recorded freshwater molluscs from ornamental pet shops and major exporters including non-ornamental species (e.g., hitchhikers, molluscs sold as fish feed). We recorded an unexpectedly high diversity—59 species—of freshwater bivalves and gastropods, with the majority (38 species or 64%) being from the Oriental region. In addition to morphological examination, we sequenced the DNA barcode region of mitochondrial CO1 and 16S genes to provide molecular data for the confirmation of the identification and for future re-identification. DNA barcodes were obtained for 50 species, and all but four were separated by > 3% uncorrected pairwise distances. The trade has been considered a main introduction pathway for non-native species to Singapore, and we found that out of 15 species in the trade as well as in the wild in Singapore, 12 are either introduced or of unknown origin, representing almost half of the known non-native freshwater molluscs in Singapore. Particularly prevalent are non-ornamental species: six hitchhikers on aquarium plants and six species sold as fish feed. We found that a quarter of the trade species have a history of introduction, which includes 11 known or potentially invasive species. We conclude that potential overharvesting is difficult to assess because only half of the trade species have been treated by IUCN. Of these, 21 species are of Least Concern and three are Data Deficient. Our checklist, with accompanying DNA barcodes, images, and museum vouchers, provides an important reference library for future

  10. Sedimentary environment influences the effect of an infaunal suspension feeding bivalve on estuarine ecosystem function.

    Directory of Open Access Journals (Sweden)

    Hannah F E Jones

    Full Text Available The suspension feeding bivalve Austrovenus stutchburyi is a key species on intertidal sandflats in New Zealand, affecting the appearance and functioning of these systems, but is susceptible to several environmental stressors including sedimentation. Previous studies into the effect of this species on ecosystem function have been restricted in space and time, limiting our ability to infer the effect of habitat change on functioning. We examined the effect of Austrovenus on benthic primary production and nutrient dynamics at two sites, one sandy, the other composed of muddy-sand to determine whether sedimentary environment alters this key species' role. At each site we established large (16 m(2 plots of two types, Austrovenus addition and removal. In winter and summer we deployed light and dark benthic chambers to quantify oxygen and nutrient fluxes and measured sediment denitrification enzyme activity to assess denitrification potential. Rates of gross primary production (GPP and ammonium uptake were significantly increased when Austrovenus was added, relative to removed, at the sandy site (GPP, 1.5 times greater in winter and summer; ammonium uptake, 8 times greater in summer; 3-factor analysis of variance (ANOVA, p<0.05. Denitrification potential was also elevated in Austrovenus addition plots at the sandy site in summer (by 1.6 times, p<0.1. In contrast, there was no effect of Austrovenus treatment on any of these variables at the muddy-sand site, and overall rates tended to be lower at the muddy-sand site, relative to the sandy site (e.g. GPP was 2.1 to 3.4 times lower in winter and summer, respectively, p<0.001. Our results suggest that the positive effects of Austrovenus on system productivity and denitrification potential is limited at a muddy-sand site compared to a sandy site, and reveal the importance of considering sedimentary environment when examining the effect of key species on ecosystem function.

  11. Persistent free radical ESR signals in marine bivalve tissues. [Electron Spin Resonance (ESR)

    Energy Technology Data Exchange (ETDEWEB)

    Mehlorn, R.J. (California Univ., Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering); Mendez, A.T. (Fundacion Educativa Ana G. Mendez, Rio Piedras (Puerto Rico)); Higashi, R. (California Univ., Bodega Bay, CA (United States). Bodega Marine Lab.); Fan, T. (California Univ., Davis, CA (United States))

    1992-08-01

    Freeze-dried homogenates of the oyster Crassostrea rhizophorae collected from waters in Puerto Rico near urban and industrial sites as well as at relatively pristine locations yielded electron spin resonance (ESR) spectra characteristic of free radicals as well as spectral components of transition metal ions, dominated by manganese. The magnitudes of these ESR signals and the concentrations of trace elements (determined by X-ray fluorescence) varied considerably among oyster samples, masking any potential correlation with polluted waters. Laboratory studies were initiated to identify the factors controlling the magnitudes of the tissue free radical ESR signals. Another mollusc, Mytilus californianus collected at the Bodega Marine laboratory in northern California, was fractionated into goneds and remaining tissue. Freeze-dried homogenates of both fractions exhibited ESR signals that increased gradually with time. ESR signals were observed in freeze-dried perchloric acid (PCA) precipitates of the homogenates, delipidated PCA precipitates, and in chloroform extracts of these precipitates. Acid hydrolysis to degrade proteins to amino acids produced a residue, which yielded much larger ESR free radical signals after freeze-drying. Freshly thawed homogenates of Crassostrea rhizophorae also exhibited ESR signals. A laboratory model of copper stress in Crassostrea rhizophorae was developed to study the effect of this transition metal on dssue free radicals. Preliminary results suggested that sublethal copper exposure had little effect on tissue fire radicals, except possibly for a signal enhancement in an oyster fraction that was enriched in kidney granules. Since kidney granules are known to accumulate heavy metals in mussels and probably other marine bivalves, this signal enhancement may prove to be an indicator of free radical processes associated with heavy metal deposition in molluscs.

  12. Habitat creation and biodiversity maintenance in mangrove forests: teredinid bivalves as ecosystem engineers

    Directory of Open Access Journals (Sweden)

    Ian W. Hendy

    2014-09-01

    Full Text Available Substantial amounts of dead wood in the intertidal zone of mature mangrove forests are tunnelled by teredinid bivalves. When the tunnels are exposed, animals are able to use tunnels as refuges. In this study, the effect of teredinid tunnelling upon mangrove forest faunal diversity was investigated. Mangrove forests exposed to long emersion times had fewer teredinid tunnels in wood and wood not containing teredinid tunnels had very few species and abundance of animals. However, with a greater cross-sectional percentage surface area of teredinid tunnels, the numbers of species and abundance of animals was significantly higher. Temperatures within teredinid-attacked wood were significantly cooler compared with air temperatures, and animal abundance was greater in wood with cooler temperatures. Animals inside the tunnels within the wood may avoid desiccation by escaping the higher temperatures. Animals co-existing in teredinid tunnelled wood ranged from animals found in terrestrial ecosystems including centipedes, crickets and spiders, and animals found in subtidal marine ecosystems such as fish, octopods and polychaetes. There was also evidence of breeding within teredinid-attacked wood, as many juvenile individuals were found, and they may also benefit from the cooler wood temperatures. Teredinid tunnelled wood is a key low-tide refuge for cryptic animals, which would otherwise be exposed to fishes and birds, and higher external temperatures. This study provides evidence that teredinids are ecosystem engineers and also provides an example of a mechanism whereby mangrove forests support intertidal biodiversity and nurseries through the wood-boring activity of teredinids.

  13. Early stage biomineralization in the periostracum of the 'living fossil' bivalve Neotrigonia.

    Directory of Open Access Journals (Sweden)

    Antonio G Checa

    Full Text Available A detailed investigation of the shell formation of the palaeoheterodont 'living fossil' Neotrigonia concentrated on the timing and manufacture of the calcified 'bosses' which stud the outside of all trigonioid bivalves (extant and fossil has been conducted. Electron microscopy and optical microscopy revealed that Neotrigonia spp. have a spiral-shaped periostracal groove. The periostracum itself is secreted by the basal cell, as a thin dark pellicle, becoming progressively transformed into a thin dark layer by additions of secretions from the internal outer mantle fold. Later, intense secretion of the internal surface of the outer mantle fold forms a translucent layer, which becomes transformed by tanning into a dark layer. The initiation of calcified bosses occurred at a very early stage of periostracum formation, deep within the periostracal groove immediately below the initialmost dark layer. At this stage, they consist of a series of polycyclically twinned crystals. The bosses grow as the periostracum traverse through the periostracal groove, in coordination with the thickening of the dark periostracal layer and until, upon reaching the mantle edge, they impinge upon each other and become transformed into large prisms separated by dark periostracal walls. In conclusion, the initial bosses and the external part of the prismatic layer are fully intraperiostracal. With later growth, the prisms transform into fibrous aggregates, although the details of the process are unknown. This reinforces the relationships with other groups that have the ability to form intraperiostracal calcifications, for example the unionoids with which the trigonioids form the clade Paleoheterodonta. The presence of similar structures in anomalodesmatans and other euheterodonts raises the question of whether this indicates a relationship or represents a convergence. The identification of very early calcification within an organic sheet has interesting implications for our

  14. Early stage biomineralization in the periostracum of the 'living fossil' bivalve Neotrigonia.

    Science.gov (United States)

    Checa, Antonio G; Salas, Carmen; Harper, Elizabeth M; Bueno-Pérez, Juan de Dios

    2014-01-01

    A detailed investigation of the shell formation of the palaeoheterodont 'living fossil' Neotrigonia concentrated on the timing and manufacture of the calcified 'bosses' which stud the outside of all trigonioid bivalves (extant and fossil) has been conducted. Electron microscopy and optical microscopy revealed that Neotrigonia spp. have a spiral-shaped periostracal groove. The periostracum itself is secreted by the basal cell, as a thin dark pellicle, becoming progressively transformed into a thin dark layer by additions of secretions from the internal outer mantle fold. Later, intense secretion of the internal surface of the outer mantle fold forms a translucent layer, which becomes transformed by tanning into a dark layer. The initiation of calcified bosses occurred at a very early stage of periostracum formation, deep within the periostracal groove immediately below the initialmost dark layer. At this stage, they consist of a series of polycyclically twinned crystals. The bosses grow as the periostracum traverse through the periostracal groove, in coordination with the thickening of the dark periostracal layer and until, upon reaching the mantle edge, they impinge upon each other and become transformed into large prisms separated by dark periostracal walls. In conclusion, the initial bosses and the external part of the prismatic layer are fully intraperiostracal. With later growth, the prisms transform into fibrous aggregates, although the details of the process are unknown. This reinforces the relationships with other groups that have the ability to form intraperiostracal calcifications, for example the unionoids with which the trigonioids form the clade Paleoheterodonta. The presence of similar structures in anomalodesmatans and other euheterodonts raises the question of whether this indicates a relationship or represents a convergence. The identification of very early calcification within an organic sheet has interesting implications for our understanding of

  15. Unionid bivalves (Mollusca: Bivalvia: Unionidae) of Presque Isle Bay, Erie, Pennsylvania

    Science.gov (United States)

    Masteller, E.C.; Maleski, K.R.; Schloesser, D.W.

    1993-01-01

    The purpose of this study was to determine species composition and relative abundance of unionid bivalves (Mollusca: Bivalvia: Unionidae) in Presque Isle Bay, Erie, Pennsylvania 1990-1992. This information was compared with data from the only other extensive survey of unionids in the bay conducted in 1909-1911 (Ortmann 1919) to assess changes over the 80 years preceding the present study. A total of 1,540 individuals representing 18 species were collected in 1990-1992. Five relatively common species (between 7 and 42% of total individuals), six uncommon species (2 and 6%), and seven rare species (<1%) were found. The rare species were Anodontoides ferussacianus, Lasmigona costata, Ligumia recta, Ptychobranchus fasciolaris, Quadrula pustulosa pustulosa, Strophitus undaulatus, and Truncilla donaciformis. Five of the species found in Presque Isle Bay (Leptodea fragilis, Ligumia nasuta, Potamilus alatus, Quadrula quadrula, and Truncilla donaciformis) are listed as critically imperiled and one species (Truncilla truncata) as extirpated in the State of Pennsylvania by the Western Pennsylvania Conservancy. Comparisons between unionid populations in 1909-1911 and 1990-1992 indicate few substantial changes occurred during the past 80 years. A total of 22 species were found; 21 in 1909-1911 and 18 in 1990-1992. Seventeen species were found in both studies, an additional four in 1909-1911 and one in 1990-1992. The relative abundance of 11 of the 17 species found in both studies remained stable (i.e., common or uncommon) over the past 80 years. Only four species listed as uncommon in 1909-1911 were listed as rare in 1990-1992. However, the invasion of the zebra mussel (Dreissena polymorpha) is considered a threat to the continued existence of the entire Unionidae fauna in Presque Isle Bay, a unique habitat of the Great Lakes.

  16. Molluscs for Sale: Assessment of Freshwater Gastropods and Bivalves in the Ornamental Pet Trade.

    Science.gov (United States)

    Ng, Ting Hui; Tan, Siong Kiat; Wong, Wing Hing; Meier, Rudolf; Chan, Sow-Yan; Tan, Heok Hui; Yeo, Darren C J

    2016-01-01

    The ornamental pet trade is often considered a key culprit for conservation problems such as the introduction of invasive species (including infectious diseases) and overharvesting of rare species. Here, we present the first assessment of the biodiversity of freshwater molluscs in the ornamental pet trade in Singapore, one of the most important global hubs of the ornamental aquarium trade, and discuss associated conservation concerns. We recorded freshwater molluscs from ornamental pet shops and major exporters including non-ornamental species (e.g., hitchhikers, molluscs sold as fish feed). We recorded an unexpectedly high diversity-59 species-of freshwater bivalves and gastropods, with the majority (38 species or 64%) being from the Oriental region. In addition to morphological examination, we sequenced the DNA barcode region of mitochondrial CO1 and 16S genes to provide molecular data for the confirmation of the identification and for future re-identification. DNA barcodes were obtained for 50 species, and all but four were separated by > 3% uncorrected pairwise distances. The trade has been considered a main introduction pathway for non-native species to Singapore, and we found that out of 15 species in the trade as well as in the wild in Singapore, 12 are either introduced or of unknown origin, representing almost half of the known non-native freshwater molluscs in Singapore. Particularly prevalent are non-ornamental species: six hitchhikers on aquarium plants and six species sold as fish feed. We found that a quarter of the trade species have a history of introduction, which includes 11 known or potentially invasive species. We conclude that potential overharvesting is difficult to assess because only half of the trade species have been treated by IUCN. Of these, 21 species are of Least Concern and three are Data Deficient. Our checklist, with accompanying DNA barcodes, images, and museum vouchers, provides an important reference library for future monitoring

  17. Impact of high pCO2 on shell structure of the bivalve Cerastoderma edule.

    Science.gov (United States)

    Milano, Stefania; Schöne, Bernd R; Wang, Schunfeng; Müller, Werner E

    2016-08-01

    Raised atmospheric emissions of carbon dioxide (CO2) result in an increased ocean pCO2 level and decreased carbonate saturation state. Ocean acidification potentially represents a major threat to calcifying organisms, specifically mollusks. The present study focuses on the impact of elevated pCO2 on shell microstructural and mechanical properties of the bivalve Cerastoderma edule. The mollusks were collected from the Baltic Sea and kept in flow-through systems at six different pCO2 levels from 900 μatm (control) to 24,400 μatm. Extreme pCO2 levels were used to determine the effects of potential leaks from the carbon capture and sequestration sites where CO2 is stored in sub-seabed geological formations. Two approaches were combined to determine the effects of the acidified conditions: (1) Shell microstructures and dissolution damage were analyzed using scanning electron microscopy (SEM) and (2) shell hardness was tested using nanoindentation. Microstructures of specimens reared at different pCO2 levels do not show significant changes in their size and shape. Likewise, the increase of pCO2 does not affect shell hardness. However, dissolution of ontogenetically younger portions of the shell becomes more severe with the increase of pCO2. Irrespective of pCO2, strong negative correlations exist between microstructure size and shell mechanics. An additional sample from the North Sea revealed the same microstructural-mechanical interdependency as the shells from the Baltic Sea. Our findings suggest that the skeletal structure of C. edule is not intensely influenced by pCO2 variations. Furthermore, our study indicates that naturally occurring shell mechanical property depends on the shell architecture at μm-scale.

  18. Deep transcriptome sequencing of Pecten maximus hemocytes: a genomic resource for bivalve immunology.

    Science.gov (United States)

    Pauletto, Marianna; Milan, Massimo; Moreira, Rebeca; Novoa, Beatriz; Figueras, Antonio; Babbucci, Massimiliano; Patarnello, Tomaso; Bargelloni, Luca

    2014-03-01

    Pecten maximus, the king scallop, is a bivalve species with important commercial value for both fisheries and aquaculture, traditionally consumed in several European countries. Major problems in larval rearing, however, still limit hatchery-based seed production. High mortalities during early larval stages, likely related to bacterial pathogens, represent the most relevant bottleneck. To address this issue, understanding host defense mechanisms against microbes is extremely important. In this study next-generation RNA-sequencing was carried on scallop hemocytes. To enrich for immune-related transcripts, cDNA libraries from hemocytes challenged in vivo with inactivated-Vibrio anguillarum and in vitro with pathogen-associated molecular patterns, as well as unchallenged controls, were sequenced yielding 216,444,674 sequence reads. De novo assembly of the scallop hemocyte transcriptome consisted of 73,732 contigs (31% annotated). A total of 934 contigs encoded proteins with a known immune function, grouped into several functional categories. Particular attention was reserved to Toll-like receptors (TLRs), a family of pattern recognition receptors (PRRs) involved in non-self recognition. Through mining the scallop hemocyte transcriptome, at least four TLRs could be identified. The organization of canonical TLR domains demonstrated that single cysteine cluster and multiple cysteine cluster TLRs co-exist in this species. In addition, preliminary data concerning their mRNA level following bacterial challenge suggested that different members of this family could exhibit opposite responses to pathogenic stimuli. Finally, a global analysis of differential expression comparing gene-expression levels in in vitro and in vivo stimulated hemocytes against controls provided evidence on a large set of transcripts involved in the great scallop immune response.

  19. Gene expression profiling of genetically determined growth variation in bivalve larvae (Crassostrea gigas).

    Science.gov (United States)

    Meyer, E; Manahan, D T

    2010-03-01

    Growth rates in animals are governed by a wide range of biological factors, many of which remain poorly understood. To identify the genes that establish growth differences in bivalve larvae, we compared expression patterns in contrasting phenotypes (slow- and fast-growth) that were experimentally produced by genetic crosses of the Pacific oyster Crassostrea gigas. Based on transcriptomic profiling of 4.5 million cDNA sequence tags, we sequenced and annotated 181 cDNA clones identified by statistical analysis as candidates for differential growth. Significant matches were found in GenBank for 43% of clones (N=78), including 34 known genes. These sequences included genes involved in protein metabolism, energy metabolism and regulation of feeding activity. Ribosomal protein genes were predominant, comprising half of the 34 genes identified. Expression of ribosomal protein genes showed non-additive inheritance - i.e. expression in fast-growing hybrid larvae was different from average levels in inbred larvae from these parental families. The expression profiles of four ribosomal protein genes (RPL18, RPL31, RPL352 and RPS3) were validated by RNA blots using additional, independent crosses from the same families. Expression of RPL35 was monitored throughout early larval development, revealing that these expression patterns were established early in development (in 2-day-old larvae). Our findings (i) provide new insights into the mechanistic bases of growth and highlight genes not previously considered in growth regulation, (ii) support the general conclusion that genes involved in protein metabolism and feeding regulation are key regulators of growth, and (iii) provide a set of candidate biomarkers for predicting differential growth rates during animal development.

  20. CO2 uptake and fixation by endosymbiotic chemoautotrophs from the bivalve Solemya velum.

    Science.gov (United States)

    Scott, Kathleen M; Cavanaugh, Colleen M

    2007-02-01

    Chemoautotrophic symbioses, in which endosymbiotic bacteria are the major source of organic carbon for the host, are found in marine habitats where sulfide and oxygen coexist. The purpose of this study was to determine the influence of pH, alternate sulfur sources, and electron acceptors on carbon fixation and to investigate which form(s) of inorganic carbon is taken up and fixed by the gamma-proteobacterial endosymbionts of the protobranch bivalve Solemya velum. Symbiont-enriched suspensions were generated by homogenization of S. velum gills, followed by velocity centrifugation to pellet the symbiont cells. Carbon fixation was measured by incubating the cells with (14)C-labeled dissolved inorganic carbon. When oxygen was present, both sulfide and thiosulfate stimulated carbon fixation; however, elevated levels of either sulfide (>0.5 mM) or oxygen (1 mM) were inhibitory. In the absence of oxygen, nitrate did not enhance carbon fixation rates when sulfide was present. Symbionts fixed carbon most rapidly between pH 7.5 and 8.5. Under optimal pH, sulfide, and oxygen conditions, symbiont carbon fixation rates correlated with the concentrations of extracellular CO(2) and not with HCO(3)(-) concentrations. The half-saturation constant for carbon fixation with respect to extracellular dissolved CO(2) was 28 +/- 3 microM, and the average maximal velocity was 50.8 +/- 7.1 micromol min(-1) g of protein(-1). The reliance of S. velum symbionts on extracellular CO(2) is consistent with their intracellular lifestyle, since HCO(3)(-) utilization would require protein-mediated transport across the bacteriocyte membrane, perisymbiont vacuole membrane, and symbiont outer and inner membranes. The use of CO(2) may be a general trait shared with many symbioses with an intracellular chemoautotrophic partner.

  1. Jackknife-corrected parametric bootstrap estimates of growth rates in bivalve mollusks using nearest living relatives.

    Science.gov (United States)

    Dexter, Troy A; Kowalewski, Michał

    2013-12-01

    Quantitative estimates of growth rates can augment ecological and paleontological applications of body-size data. However, in contrast to body-size estimates, assessing growth rates is often time-consuming, expensive, or unattainable. Here we use an indirect approach, a jackknife-corrected parametric bootstrap, for efficient approximation of growth rates using nearest living relatives with known age-size relationships. The estimate is developed by (1) collecting a sample of published growth rates of closely related species, (2) calculating the average growth curve using those published age-size relationships, (3) resampling iteratively these empirically known growth curves to estimate the standard errors and confidence bands around the average growth curve, and (4) applying the resulting estimate of uncertainty to bracket age-size relationships of the species of interest. This approach was applied to three monophyletic families (Donacidae, Mactridae, and Semelidae) of mollusk bivalves, a group characterized by indeterministic shell growth, but widely used in ecological, paleontological, and geochemical research. The resulting indirect estimates were tested against two previously published geochemical studies and, in both cases, yielded highly congruent age estimates. In addition, a case study in applied fisheries was used to illustrate the potential of the proposed approach for augmenting aquaculture management practices. The resulting estimates of growth rates place body size data in a constrained temporal context and confidence intervals associated with resampling estimates allow for assessing the statistical uncertainty around derived temporal ranges. The indirect approach should allow for improved evaluation of diverse research questions, from sustainability of industrial shellfish harvesting to climatic interpretations of stable isotope proxies extracted from fossil skeletons.

  2. Immunomodulation by different types of N-oxides in the hemocytes of the marine bivalve Mytilus galloprovincialis.

    Directory of Open Access Journals (Sweden)

    Caterina Ciacci

    Full Text Available The potential toxicity of engineered nanoparticles (NPs for humans and the environment represents an emerging issue. Since the aquatic environment represents the ultimate sink for NP deposition, the development of suitable assays is needed to evaluate the potential impact of NPs on aquatic biota. The immune system is a sensitive target for NPs, and conservation of innate immunity represents an useful basis for studying common biological responses to NPs. Suspension-feeding invertebrates, such as bivalves, are particularly at risk to NP exposure, since they have extremely developed systems for uptake of nano and microscale particles integral to intracellular digestion and cellular immunity. Evaluation of the effects of NPs on functional parameters of bivalve immunocytes, the hemocytes, may help understanding the major toxic mechanisms and modes of actions that could be relevant for different NP types in aquatic organisms.In this work, a battery of assays was applied to the hemocytes of the marine bivalve Mytilus galloprovincialis to compare the in vitro effects of different n-oxides (n-TiO(2, n-SiO(2, n-ZnO, n-CeO(2 chosen on the basis of their commercial and environmental relevance. Physico-chemical characterization of both primary particles and NP suspensions in artificial sea water-ASW was performed. Hemocyte lysosomal and mitochondrial parameters, oxyradical and nitric oxide production, phagocytic activity, as well as NP uptake, were evaluated. The results show that different n-oxides rapidly elicited differential responses hemocytes in relation to their chemical properties, concentration, behavior in sea water, and interactions with subcellular compartments. These represent the most extensive data so far available on the effects of NPs in the cells of aquatic organisms. The results indicate that Mytilus hemocytes can be utilized as a suitable model for screening the potential effects of NPs in the cells of aquatic invertebrates, and may

  3. The evolutionary ecology of biotic association in a megadiverse bivalve superfamily: sponsorship required for permanent residency in sediment.

    Directory of Open Access Journals (Sweden)

    Jingchun Li

    Full Text Available BACKGROUND: Marine lineage diversification is shaped by the interaction of biotic and abiotic factors but our understanding of their relative roles is underdeveloped. The megadiverse bivalve superfamily Galeommatoidea represents a promising study system to address this issue. It is composed of small-bodied clams that are either free-living or have commensal associations with invertebrate hosts. To test if the evolution of this lifestyle dichotomy is correlated with specific ecologies, we have performed a statistical analysis on the lifestyle and habitat preference of 121 species based on 90 source documents. METHODOLOGY/PRINCIPAL FINDINGS: Galeommatoidea has significant diversity in the two primary benthic habitats: hard- and soft-bottoms. Hard-bottom dwellers are overwhelmingly free-living, typically hidden within crevices of rocks/coral heads/encrusting epifauna. In contrast, species in soft-bottom habitats are almost exclusively infaunal commensals. These infaunal biotic associations may involve direct attachment to a host, or clustering around its tube/burrow, but all commensals locate within the oxygenated sediment envelope produced by the host's bioturbation. CONCLUSIONS/SIGNIFICANCE: the formation of commensal associations by Galeommatoidean clams is robustly correlated with an abiotic environmental setting: living in sediments (P < 0.001. Sediment-dwelling bivalves are exposed to intense predation pressure that drops markedly with depth of burial. Commensal galeommatoideans routinely attain depth refuges many times their body lengths, independent of siphonal investment, by virtue of their host's burrowing and bioturbation. In effect, they use their much larger hosts as giant auto-irrigating siphon substitutes. The evolution of biotic associations with infaunal bioturbating hosts may have been a prerequisite for the diversification of Galeommatoidea in sediments and has likely been a key factor in the success of this exceptionally diverse

  4. Chemosymbiotic bivalves from the mud volcanoes of the Gulf of Cadiz, NE Atlantic, with descriptions of new species of Solemyidae, Lucinidae and Vesicomyidae.

    Science.gov (United States)

    Olive, Graham; Rodrigues, Clara F; Cunha, Marina R

    2011-01-01

    The chemosymbiotic bivalves collected from the mud volcanoes of the Gulf of Cadiz are reviewed. Of the thirteen species closely associated with chemosynthetic settings two Solemyidae, Solemya (Petrasma) elarraichensissp. n. and Acharax gadiraesp. n., one Lucinidae, Lucinoma asapheussp. n., and one Vesicomyidae, Isorropodon megadesmussp. n. are described and compared to close relatives of their respective families. The biodiversity and distribution of the chemosymbiotic bivalves in the Gulf of Cadiz are discussed and compared to the available information from other cold seeps in the Eastern Atlantic and Mediterranean. Although there is considerable similarity at the genus level between seep/mud volcano fields in the Eastern Atlantic and Mediterranean, there is little overlap at the species level. This indicates a high degree of endemism within chemosymbiotic bivalve assemblages.

  5. Interactions between Mytilus galloprovincialis hemocytes and the bivalve pathogens Vibrio aestuarianus 01/032 and Vibrio splendidus LGP32.

    Science.gov (United States)

    Balbi, T; Fabbri, R; Cortese, K; Smerilli, A; Ciacci, C; Grande, C; Vezzulli, L; Pruzzo, C; Canesi, L

    2013-12-01

    Marine bivalves can accumulate large numbers of bacteria, in particular Vibrio species, whose persistence in bivalve tissues largely depends on their sensitivity to the bactericidal activity of circulating hemocytes and hemolymph soluble factors. The interactions between vibrios and hemolymph have been investigated, in particular in bivalve species susceptible to infection by certain Vibrio spp. and strains. In this work, the effects of two bivalve pathogens, Vibrio splendidus LGP32 (V.s.) and Vibrio aestuarianus 01/032 (V.a.), isolated from oyster mortality outbreaks, on the hemocytes of Mytilus galloprovincialis were investigated. In vitro, V.s., but not V.a., induced a dramatic decrease in lysosomal membrane stability-LMS in the hemocytes; both vibrios induced a moderate lysozyme release, with V.s. > V.a.. The V.s.-induced decrease in LMS was mediated by activation of PI-3Kinase, as shown by use of different kinase inhibitors. TEM analysis showed rapid internalization of both vibrios; however, V.s. lead to cellular and lysosomal damage and was able to survive within the hemocytes, whereas significant killing of V.a. was observed. In vivo, in mussels challenged with either vibrio and sampled at 6, 24 and 96 h post-injection, transient decreases in hemocyte LMS and progressive increases in serum lysozyme activity were observed, with V.s. > V.a.. Moreover, whereas V.a. was efficiently cleared from hemolymph, V.s. showed significant growth, that was maximal at 24 h p.i. when lowest LMS values were recorded in the hemocytes. Both vibrios also induced significant decreases in LMS in the digestive gland, again with V.s. > V.a.. The results indicate distinct interactions between mussel hemocytes and the two vibrio strains tested. The effects of V.s. may be due to the capacity of this strain to interfere with the signaling pathways involved in hemocyte function, thus escaping the bactericidal activity of the host cell, as observed for certain mammalian pathogens

  6. Alkylphenols and polycyclic aromatic hydrocarbons in bivalves from Comunidad Valenciana coastal waters; Alquilfenoles e hidrocarburos aromaticos policiclicos en bivalvos de las coastas de la comunidad Valenciana

    Energy Technology Data Exchange (ETDEWEB)

    Marti Ortega, N.; Aguado Garcia, D.; Bouzas Blanco, A.; Segovia Martinez, L.; Albargues Llamas, M.; Sevillano Cabeza, A.; Campins Falco, P.; Seco Torrecillas, A.; Ferrer Polo, J.

    2009-07-01

    This paper reports the results on alkylphenol and polycyclic aromatic hydrocarbons (PAH) pollution in mussels and cleans from Comunidad Valenciana coastal waters, in 2008. The significant presence of nonylphenol observed in both bivalves reflects an exposure to alkyl phenolic surfactants from the discharges of wastewater treatment plants that treat industrial and urban wastewaters, where the presence of alkylphenol polyethoxylated is common due to its extensive use (detergents, solubilizers...). The presence of low levels of PAH was observed in most of the studied areas. However, it must be highlighted that bivalves consumption does not imply any risk for human health. (Author) 21 refs.

  7. Effects of ocean acidification on the metabolic rates of three species of bivalve from southern coast of China

    Institute of Scientific and Technical Information of China (English)

    LIU Wenguang; HE Maoxian

    2012-01-01

    Oceanic uptake of anthropogenic carbon dioxide results in a decrease in seawater pH,a process known as “ocean acidification”.The pearl oyster Pinctada fucata,the noble scallop Chlamys nobilis,and the green-lipped mussel Perna viridis are species of economic and ecological importance along the southern coast of China.We evaluated the effects of seawater acidification on clearance,respiration,and excretion rates in these three species.The animals were reared in seawater at pH 8.1 (control),7.7,or 7.4.The clearance rate was highest at pH 7.7 for P.fucata and at pH 8.1 for C.nobilis and P.viridis.The pH had little effect on the respiration rate of P.fucata and P.viridis.In contrast,the respiration rate was significantly lower at pH 7.4 in C.nobilis.The excretion rate was significantly lower at pH 7.4 than pH 8.1 for all species.The results indicate that the reduction in seawater pH likely affected the metabolic process (food intake,oxygen consumption,and ammonia excretion) of these bivalves.Different species respond differently to seawater acidification.Further studies are needed to demonstrate the exact mechanisms for this effect and evaluate adaptability of these bivalves to future acidified oceans.

  8. A new sediment-dwelling pholadid bivalve from Oligocene glaciomarine sediments of King George Island, West Antarctica

    Directory of Open Access Journals (Sweden)

    Krzysztof Hryniewicz

    2016-12-01

    Full Text Available We present a re-description of the pholadid bivalve from the Oligocene Polonez Cove Formation, King George Island, West Antarctica, previously identified as Penitella sp. The study is based on a collection of 210 specimens, preserved exclusively in life position in flask-shaped Gastrochaenolites type borings which have been subsequently buried by glaciomarine diamictite. The systematic study showed that this pholadid is a new species belonging to the genus Pholadidea rather than to Penitella and we name it Pholadidea gradzinskii sp. nov. The species is one of very few Late Cretaceous–Paleogene pholadids that we could safely identify as Pholadidea. All of them are known exclusively from the southern Pacific and adjacent areas (New Zealand, Antarctica, and Patagonia. We demonstrate that the genus attained its Recent broad distribution before the middle Miocene, when the first species of Pholadidea appeared in the Northern Hemisphere. The mass occurrence of P. gradzinskii in the Oligocene of West Antarctica results from favourable living condition in a shallow marine environment. Low sedimentation rate allowed the settlement of numerous larvae and their subsequent metamorphosis, growth, and maturity terminated by the mass mortality caused by the burial by marine diamictite. The sediment-boring Paleogene species of Pholadidea, among them P. gradzinskii, follow the wood-boring Late Cretaceous species P. (Hatasia wiffenae, which reflects a general pattern of evolution of substrate selection among pholadoid bivalves.

  9. Early and late lithification of aragonitic bivalve beds in the Purbeck Formation (upper jurassic-lower cretaceous) of Southern England

    Science.gov (United States)

    El-Shahat, Adam; West, Ian

    1983-05-01

    Beds of euryhaline bivalves alternating with shales constitute much of the middle Purbeck Formation. They originated on "tidal" flats at the western margin of an extensive brackish lagoon. When these shell beds are thin and enclosed in shale they are often still preserved as aragonite and are associated with "beef", fibrous calcite formed during compaction. In most cases, however, the shell debris has been converted by diagenesis into calcitic biosparrudite limestones. A compacted type has been lithified at a late stage, after deep burial. In this, pyrite is abundant and most of the shell aragonite has been replaced neomorphically by ferroan pseudopleochroic calcite. A contrasting uncompacted type of biosparrudite is characterised by bivalve fragments with micrite envelopes. Shells and former pores are occupied by non-ferroan sparry calcite cement, and there is little pyrite. These limestones frequently contain dinosaur footprints and originated in "supratidal" environments where they were cemented early, mainly in meteoric water. Once lithified they were unaffected by compaction. This uncompacted type indicates phases of mild uplift or halts in subsidence. These shell-bed lithologies, and also intermediate types described here, will probably be recognised in other lagoonal formations.

  10. Synchrotron-based crystal structure, associated morphology of snail and bivalve shells by X-ray diffraction

    Science.gov (United States)

    Rao, D. V.; Gigante, G. E.; Kumar, Y. Manoj; Cesareo, R.; Brunetti, A.; Schiavon, N.; Akatsuka, T.; Yuasa, T.; Takeda, T.

    2016-10-01

    Synchrotron-based high-resolution X-ray powder diffraction spectra from the body parts of a snail and bivalve (CaCO3), have been recorded with Pilatus area detector. Experiments were performed at Desy, Hamburg, Germany, utilizing the Resonant and Diffraction beamline (P9), with 15 keV X-rays (λ=0.82666 Å). The external shell of these living organisms, is composed of calcium carbonate, which carries strong biological signal. It consists of some light elements, such as, Ca, C and O, which constitute part of the soft tissue and other trace elements. The knowledge of these diffraction patterns and hence the understanding of structures at molecular level are enormous. The application of synchrotron radiation to powder diffraction is well suited for samples of biological nature via changes in their patterns and also to investigate crystallographic phase composition. With the use of Rietveld refinement procedure, to the high-resolution diffraction spectra, we were able to extract the lattice parameters of orthorhombic polymorph of CaCO3, the most abundant mineral produced by these living organisms. The small size of the crystallite is a very important factor related to the biological structure. The natural model presents a combination of organic and inorganic phases with nanometer size. For the present study, we also used the scanning electron microscopy (SEM) to explore the associated morphology of the snail and bivalve.

  11. The vesicomyid bivalve habitat at cold seeps supports heterogeneous and dynamic macrofaunal assemblages

    Science.gov (United States)

    Guillon, Erwan; Menot, Lénaïck; Decker, Carole; Krylova, Elena; Olu, Karine

    2017-02-01

    The high biodiversity found at cold seeps, despite elevated concentrations of methane and hydrogen sulfide, is attributed to multiple sources of habitat heterogeneity. In addition to geological and geochemical processes, biogenic habitats formed by large symbiont-bearing taxa, such as bivalves and siboglinid tubeworms, or by microbial mats drive the biodiversity of small-sized fauna. However, because these habitat-forming species also depend on geochemical gradients, the respective influence of abiotic and biotic factors in structuring associated macrofaunal communities is often unresolved. The giant pockmark Regab located at 3200 m depth on the Congo margin is characterized by different fluid-flow regimes, providing a mosaic of the most common biogenic habitats encountered at seeps: microbial mats, mussel beds, and vesicomyid clam beds; the latter being distributed along a gradient of environmental conditions from the center to the periphery of the pockmark. Here, we examined the structure of macrofaunal communities in biogenic habitats formed in soft sediment to (1) determine the influence of the habitats on the associated macrofaunal communities (inter-habitat comparison), (2) describe how macrofaunal communities vary among vesicomyid clam beds (intra-habitat comparison) and (3) assess the inter-annual variation in vesicomyid beds based on repeated sampling at a three-year interval. The highest densities were found in the microbial mat communities in intermediate fluid-flow areas, but they had low diversity - also observed in the sediment close to mussel beds. In contrast, vesicomyid beds harbored the highest diversity. The vesicomyid beds did not show a homogeneous macrofaunal community across sampled areas; instead, density and composition of macrofauna varied according to the location of the beds inside the pockmark. The clam bed sampled in the most active, central part of the pockmark resembled bacterial mat communities by the presence of highly sulfide

  12. Gal/GalNAc specific multiple lectins in marine bivalve Anadara granosa.

    Science.gov (United States)

    Adhya, Mausumi; Singha, Biswajit

    2016-03-01

    Complete lectin mapping of molluscs with their diversified recognition pattern and possible role in lectin-carbohydrate interaction based immune response triggering need much attention. In this communication, Gal/GalNAc specific three lectins AGL-IA (Anadara granosa lectin-IA), AGL-IB (A. granosa lectin-IB) and AGL-IV (A. granosa lectin-IV) and a lectin having hemolytic activity AGL-III (A. granosa lectin-III) were purified from the plasma of A. granosa bivalve by a combination of gel filtration and affinity chromatography. AGL-IA and IB were oligomeric lectins whereas, AGL-III and IV were monomeric. The molecular weight of AGL-IA, IB, III and IV were 375, 260, 45 and 33 kDa respectively. AGL-IA and IV agglutinated both rabbit and pronase treated human erythrocytes, whereas AGL-IB agglutinated only rabbit erythrocytes. AGL-III was found to agglutinate rabbit erythrocytes, however, it caused hemolysis of pronase treated human erythrocytes. The activity of all four lectins was calcium dependent and maximum at a pH range 7-8. Apart from Gal/GalNAc specific, the four lectins showed substantial differences in their carbohydrate recognition pattern. Moreover, there was a difference in the carbohydrate specificity between AGL-III and other three lectins (AGL-IA, AGL-IB and AGL-IV) towards polyvalent glycotope. On the one hand, 'cluster glycoside effect' i.e., an enhancement of the activity of a multivalent ligand, was observed for carbohydrate specificities of AGL-IA, AGL-IB, AGL-IV. On the other hand, the effect of multivalent ligands on the carbohydrate specificity of AGL-III was opposite of cluster glycoside effect. The affinity of AGL-IA, AGL-IB and AGL-IV for ligands can be ranked as follows: glycoproteins > polysaccharide > oligosaccharides and monosaccharides. However, Gal related monosaccharides were the best inhibitors of AGL-III and the inhibitory activity decreased gradually in the following order: monosaccharide > disaccharide > polysaccharide. Thus, the

  13. High-resolution nitrogen stable isotope sclerochronology of bivalve shell carbonate-bound organics

    Science.gov (United States)

    Gillikin, David P.; Lorrain, Anne; Jolivet, Aurélie; Kelemen, Zita; Chauvaud, Laurent; Bouillon, Steven

    2017-03-01

    work should use compound specific isotope analyses (CSIA) to test this hypothesis, and to determine whether certain amino acids could specifically track N sources or possibly identify amino acids that are more resistant to diagenesis in fossil shells. In conclusion, bivalve shell CBOM δ15N values can be used in a similar manner to soft-tissue δ15N values, and can track various biogeochemical events at a very high-resolution.

  14. Investigations of the capacity of synthesizing 3β-sterols in mollusca—XIII. Biosynthesis and composition of sterols in some bivalves (Anisomyaria)

    NARCIS (Netherlands)

    Voogt, P.A.

    1975-01-01

    1. The incorporation of sodium acetate-1- or -2-¹⁴C into some lipid classes of the anisomyarian bivalves Mytilus edulis, Atrina fragilis and Ostrea edulis was investigated. 2. It was demonstrated that the acetate was utilized for the biosynthesis of both saponifiable and non-saponifiable lipids. 3.

  15. History of bioavailable lead and iron in the Greater North Sea and Iceland during the last millennium - a bivalve sclerochronological reconstruction.

    Science.gov (United States)

    Holland, Hilmar A; Schöne, Bernd R; Marali, Soraya; Jochum, Klaus P

    2014-10-15

    We present the first annually resolved record of biologically available Pb and Fe in the Greater North Sea and Iceland during 1040-2004 AD based on shells of the long-lived marine bivalve Arctica islandica. The iron content in pre-industrial shells from the North Sea largely remained below the detection limit. Only since 1830, shell Fe levels rose gradually reflecting the combined effect of increased terrestrial runoff of iron-bearing sediments and eutrophication. Although the lead gasoline peak of the 20th century was well recorded by the shells, bivalves that lived during the medieval heyday of metallurgy showed four-fold higher shell Pb levels than modern specimens. Presumably, pre-industrial bivalves were offered larger proportions of resuspended (Pb-enriched) organics, whereas modern specimens receive fresh increased amounts of (Pb-depleted) phytoplankton. As expected, metal loads in the shells from Iceland were much lower. Our study confirms that bivalve shells provide a powerful tool for retrospective environmental biomonitoring.

  16. Field clearance of an intertidal bivalve bed: relative significance of the co-occurring blue mussel Mytilus edulis and Pacific oyster Crassostrea gigas

    DEFF Research Database (Denmark)

    Vismann, Bent; Holm, Mark Wejlemann; Davids, Jens;

    2016-01-01

    At an approximately 12 000 m2 sheltered intertidal bivalve bed in the western part of the Limfjord, Denmark, the Pacific oyster Crassostrea gigas co-occurs with the blue mussel Mytilus edulis. The relative significance of the impact of the 2 species on phytoplankton density during a tidal cycle...

  17. Biomonitoring of Heavy metals using the bivalve molluscs in sunderban mangrove wetland, Northeast Coast of Bay of bengal (india): possible risks to Human health

    Energy Technology Data Exchange (ETDEWEB)

    Cabral, Henrique; Cardoso, Ines [Departamento de Biologia Animal/Instituto de Oceanografia, Campo Grande, Lisboa (Portugal); Chatterjee, Mousumi; Kumar Bhattacharya, Asok; Aftab Alam, Mohammad [Department of Marine Science, University of Calcutta, Calcutta (India); Kanta Satpathy, Kamala [Indira Gandhi Centre for Atomic Research, Environmental and Industrial Safety Section, Safety Group, Kalpakkam, Tamil Nadu (India); Kumar Sarkar, Santosh

    2008-02-15

    The suitability of using four bivalve molluscs (Sanguinolaria acuminata, Anadara granosa, Meretrix meretrix, and Pelecyora trigona) in biomonitoring of heavy metals (Cu, Pb, Cd, Zn, and Hg) collected from intertidal regions of the Sunderban mangrove wetland, northeastern part of the Bay of Bengal, were evaluated. Both speciesdependent variability and temporal variations were pronounced. A high degree of organ specificity was evident in the bivalves where gill and mantle exhibited higher metal accumulation due to ion exchange property of the mucous layer covering these organs while shells represent very poor accumulation. Elevated values of Zn and Cu reflect high potential for biomagnification through marine food chain. Metal concentrations in different body size groups of the bivalves do not follow uniform trend. Correlation coefficient between different metal couplings as tested statistically revealed significant coupling for Pb-Zn, Pb-Cu, Zn-Cu, and Hg-Cu. Concentrations of all the metals in specific organs (visceral mass, mantle and gill) of the bivalves exceeded the safe levels according to the international standards for metals compiled by Food and Agricultural Organization of the United Nations and would be of great risk for human consumption. It is concluded that the mussel and clam are suitable biomonitors to employ in programs designed to assess changes in metal pollution in the Sunderban mangrove wetland. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  18. Structural characterization of the N-glycans of gp273, the ligand for sperm-egg interaction in the mollusc bivalve Unio elongatulus

    NARCIS (Netherlands)

    Vliegenthart, J.F.G.; Di Patrizi, L.; Capone, A.; Focarelli, R.; Rosati, F.; Gutiérrez Gallego, R.; Gerwig, G.J.

    2001-01-01

    Gp273, a glycoprotein of the egg extracellular coats of the mollusc bivalve Unio elongatulus, is the ligand molecule for sperm-egg interaction during fertilization. In this study we have analyzed the N-glycans from gp273. N-glycans were enzymatically released by PNGase F digestion and their structur

  19. Systematics, functional morphology and distribution of a bivalve (Apachecorbula muriatica gen. et sp. nov.) from the rim of the 'Valdivia Deep' brine pool in the Red Sea

    KAUST Repository

    Oliver, Pere Graham

    2014-11-11

    The deep brine pools of the Red Sea comprise extreme, inhospitable habitats yet house microbial communities that potentially may fuel adjacent fauna. We here describe a novel bivalve from a deep-sea (1525 m) brine pool in the Red Sea, where conditions of high salinity, lowered pH, partial anoxia and high temperatures are prevalent. Remotely operated vehicle (ROV) footage showed that the bivalves were present in a narrow (20 cm) band along the rim of the brine pool, suggesting that it is not only tolerant of such extreme conditions but is also limited to them. The bivalve is a member of the Corbulidae and named Apachecorbula muriatica gen. et sp. nov. The shell is atypical of the family in being modioliform and thin. The semi-infaunal habit is seen in ROV images and reflected in the anatomy by the lack of siphons. The ctenidia are large and typical of a suspension feeding bivalve, but the absence of \\'guard cilia\\' and the greatly reduced labial palps suggest that it is non-selective as a response to low food availability. It is proposed that the low body mass observed is a consequence of the extreme habitat and low food availability. It is postulated that the observed morphology of Apachecorbula is a result of paedomorphosis driven by the effects of the extreme environment on growth but is in part mitigated by the absence of high predation pressures. © Marine Biological Association of the United Kingdom, 2014.

  20. 中国寒武纪双壳类研究之评述%REVIEW OF THE STUDY OF CAMBRIAN BIVALVES IN CHINA

    Institute of Scientific and Technical Information of China (English)

    方宗杰

    2004-01-01

    The genus Yangtzedonta Yu,1985 have not been accepted by bivalve specialists as a bivalve as Yu originally reported in studying early phylogeny and evolution of the class Bivalvia. Recently,Qian Yi(2001)solved this puzzle.He confirms that Y.primitiva Yu is only an incomplete specimen of Xianfengella prima He et Yang,a problematical small shelly fossil.It is a pity that Qian confused Xianfengoconcha elliptica Zhang with the oldest certain bivalve. It is necessary to review comprehensively the study of Cambrian bivalves in China.Xiangfengoconcha Zhang,1980 shows an elongate,weakly inclined anterior and posterior toothlike structure on each side of the beak.This is an obolellid type hinge structure rather than the bivalve palaeoheterodont type.Moreover lamellar teeth of palaeoheterodonts were derived from the fusion of discrete teeth of palaeotaxodont type.Therefore,it is unlikely that the most primitive bivalve was such a form with lamellar teeth as Xianfengoconcha elliptica Zhang.At present,Pojetaia Jell,1980 is the only undoubted Cambrian bivalve in China.%长期以来,双壳类研究者虽未将扬子蛤(Yangtzedonta Yu)纳入到双壳类早期系统演化的研究范畴,却又难以予以完全否定.最近,钱逸的工作终于解决了这一悬案,这是寒武纪带壳软体动物研究的一项重要进展.然而,钱逸对双壳类早期演化的理解仍存在着误解,例如,将Xianfengoconcha Zhang当作是"最古老的双壳类",为此有必要对近二十年来我国寒武纪双壳类的研究进行回顾与总结.Xianfengoconcha发育有两侧对称排列的所谓"片状齿",实属腕足类小圆货贝型铰合构造.化石证据表明,真正的片状齿是由古栉齿型铰齿演化而来,因此,古异齿型不是双壳类最古老的铰齿类型.目前,我国没有争议的寒武纪双壳类只有Pojetaia Jell一属.

  1. Short- and long-term consequences of larval stage exposure to constantly and ephemerally elevated carbon dioxide for marine bivalve populations

    Directory of Open Access Journals (Sweden)

    C. J. Gobler

    2013-04-01

    Full Text Available While larval bivalves are highly sensitive to ocean acidification, the basis for this sensitivity and the longer-term implications of this sensitivity are unclear. Experiments were performed to assess the short-term (days and long-term (months consequences of larval stage exposure to varying CO2 concentrations for calcifying bivalves. Higher CO2 concentrations depressed both calcification rates assessed using 45Ca uptake and RNA : DNA ratios in Mercenaria mercenaria and Argopecten irradians larvae with RNA : DNA ratios being highly correlated with larval growth rates (r2>0.9. These findings suggested that high CO2 has a cascading negative physiological impact on bivalve larvae stemming in part from lower calcification rates. Exposure to elevated CO2 during the first four days of larval development significantly depressed A. irradians larval survival rates, while a 10-day exposure later in larval development did not, demonstrating the extreme CO2 sensitivity of bivalve larvae during first days of development. Short- (weeks and long-term (10 month experiments revealed that individuals surviving exposure to high CO2 during larval development grew faster when exposed to normal CO2 as juveniles compared to individuals reared under ambient CO2 as larvae. These increased growth rates could not, however, overcome size differences established during larval development, as size deficits of individuals exposed to even moderate levels of CO2 as larvae were evident even after 10 months of growth under normal CO2 concentrations. This "legacy effect" emphasizes the central role larval stage CO2 exposure can play in shaping the success of modern-day bivalve populations.

  2. Cephalic and limb anatomy of a new Isoxyid from the Burgess Shale and the role of "stem bivalved arthropods" in the disparity of the frontalmost appendage.

    Science.gov (United States)

    Aria, Cédric; Caron, Jean-Bernard

    2015-01-01

    We herein describe Surusicaris elegans gen. et sp. nov. (in Isoxyidae, amended), a middle (Series 3, Stage 5) Cambrian bivalved arthropod from the new Burgess Shale deposit of Marble Canyon (Kootenay National Park, British Columbia). Surusicaris exhibits 12 simple, partly undivided biramous trunk limbs with long tripartite caeca, which may illustrate a plesiomorphic "fused" condition of exopod and endopod. We construe also that the head is made of five somites (= four segments), including two eyes, one pair of anomalocaridid-like frontalmost appendages, and three pairs of poorly sclerotized uniramous limbs. This fossil may therefore be a candidate for illustrating the origin of the plesiomorphic head condition in euarthropods, and questions the significance of the "two-segmented head" in, e.g., fuxianhuiids. The frontalmost appendage in isoxyids is intriguingly disparate, bearing similarities with both dinocaridids and euarthropods. In order to evaluate the relative importance of bivalved arthropods, such as Surusicaris, in the hypothetical structuro-functional transition between the dinocaridid frontal appendage and the pre-oral-arguably deutocerebral-appendage of euarthropods, we chose a phenetic approach and computed morphospace occupancy for the frontalmost appendages of 36 stem and crown taxa. Results show different levels of evolutionary decoupling between frontalmost appendage disparity and body plans. Variance is greatest in dinocaridids and "stem bivalved" arthropods, but these groups do not occupy the morphospace homogeneously. Rather, the diversity of frontalmost appendages in "stem bivalved" arthropods, distinct in its absence of clear clustering, is found to link the morphologies of "short great appendages," chelicerae and antennules. This find fits the hypothesis of an increase in disparity of the deutocerebral appendage prior to its diversification in euarthropods, and possibly corresponds to its original time of development. The analysis of this

  3. Subcellular partitioning of cadmium in the freshwater bivalve, Pyganodon grandis, after separate short-term exposures to waterborne or diet-borne metal

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Sophie; Hare, Landis [INRS-Eau, Terre et Environnement, Universite du Quebec, 490 rue de la Couronne, Quebec, QC, G1K 9A9 (Canada); Campbell, Peter G.C., E-mail: peter.campbell@ete.inrs.ca [INRS-Eau, Terre et Environnement, Universite du Quebec, 490 rue de la Couronne, Quebec, QC, G1K 9A9 (Canada)

    2010-11-15

    The dynamics of cadmium uptake and subcellular partitioning were studied in laboratory experiments conducted on Pyganodon grandis, a freshwater unionid bivalve that shows promise as a biomonitor for metal pollution. Bivalves were collected from an uncontaminated lake, allowed to acclimate to laboratory conditions ({>=}25 days), and then either exposed to a low, environmentally relevant, concentration of dissolved Cd (5 nM; 6, 12 and 24 h), or fed Cd-contaminated algae ({approx}70 nmol Cd g{sup -1} dry weight; 4 x 4 h). In this latter case, the bivalves were allowed to depurate for up to 8 days after the end of the feeding phase. As anticipated, the gills were the main target organ during the aqueous Cd exposure whereas the intestine was the initial site of Cd accumulation during the dietary exposure; during the subsequent depuration period, the dietary Cd accumulated in both the digestive gland and in the gills. For the gills, the distribution of Cd among the subcellular fractions (i.e., granules > heat-denatured proteins (HDP) {approx} heat-stable proteins (HSP) > mitochondria {approx} lysosomes + microsomes) was insensitive to the exposure route; both waterborne and diet-borne Cd ended up largely bound to the granule fraction. The subcellular distribution of Cd in the digestive gland differed markedly from that in the gills (HDP > HSP {approx} granules {approx} mitochondria > lysosomes + microsomes), but as in the case of the gills, this distribution was relatively insensitive to the exposure route. For both the gills and the digestive gland, the subcellular distributions of Cd differed from those observed in native bivalves that are chronically exposed to Cd in the field - in the short-term experimental exposures of P. grandis, metal detoxification was less effective than in chronically exposed native bivalves.

  4. Cephalic and limb anatomy of a new Isoxyid from the Burgess Shale and the role of "stem bivalved arthropods" in the disparity of the frontalmost appendage.

    Directory of Open Access Journals (Sweden)

    Cédric Aria

    Full Text Available We herein describe Surusicaris elegans gen. et sp. nov. (in Isoxyidae, amended, a middle (Series 3, Stage 5 Cambrian bivalved arthropod from the new Burgess Shale deposit of Marble Canyon (Kootenay National Park, British Columbia. Surusicaris exhibits 12 simple, partly undivided biramous trunk limbs with long tripartite caeca, which may illustrate a plesiomorphic "fused" condition of exopod and endopod. We construe also that the head is made of five somites (= four segments, including two eyes, one pair of anomalocaridid-like frontalmost appendages, and three pairs of poorly sclerotized uniramous limbs. This fossil may therefore be a candidate for illustrating the origin of the plesiomorphic head condition in euarthropods, and questions the significance of the "two-segmented head" in, e.g., fuxianhuiids. The frontalmost appendage in isoxyids is intriguingly disparate, bearing similarities with both dinocaridids and euarthropods. In order to evaluate the relative importance of bivalved arthropods, such as Surusicaris, in the hypothetical structuro-functional transition between the dinocaridid frontal appendage and the pre-oral-arguably deutocerebral-appendage of euarthropods, we chose a phenetic approach and computed morphospace occupancy for the frontalmost appendages of 36 stem and crown taxa. Results show different levels of evolutionary decoupling between frontalmost appendage disparity and body plans. Variance is greatest in dinocaridids and "stem bivalved" arthropods, but these groups do not occupy the morphospace homogeneously. Rather, the diversity of frontalmost appendages in "stem bivalved" arthropods, distinct in its absence of clear clustering, is found to link the morphologies of "short great appendages," chelicerae and antennules. This find fits the hypothesis of an increase in disparity of the deutocerebral appendage prior to its diversification in euarthropods, and possibly corresponds to its original time of development. The

  5. Bivalves Antárticos e Subantárticos coletados durante as Expedições Científicas Brasileiras à Antártica I a IX (1982-1991 Antarctic and Subantarctic bivalves collected during the Scientific, Brazilian Expeditions to Antarctica I-IX (1982-1991

    Directory of Open Access Journals (Sweden)

    Walter Narchi

    2002-09-01

    Full Text Available The bivalves collected in the Western Antarctic and Subantarctic waters by scientists of the Instituto Oceanográfico - USP during the Scientific Brazilian Expeditions to Antarctical-IX are characterised through its conchiliological features, illustrated and their occurrence plotted in maps. A species of bivalve collected by scuba divers of the IO-USP on the Napier Rock, Admiralty Bay, King George Island during the Expeditions XV and XVI is also considered in this work. The material identified is representative of 25 species distributed among three families and four genera of Protobranchia, three farnilies and five genera of Pteriornorpha, five families and six genera of Heterodonta, and four families and four genera of Anomalo desmata. The main scope of this work is to provide searchers dealing with macrobenthic fauna with an ease identification guide to the bivalved molluscs of the sampled region.

  6. Soluble organic matrices of the calcitic prismatic shell layers of two Pteriomorphid bivalves. Pinna nobilis and Pinctada margaritifera.

    Science.gov (United States)

    Dauphin, Yannicke

    2003-04-25

    The calcitic prisms of the shells of two bivalves, Pinna and Pinctada, are considered simple prisms according to some morphological and mineralogical characteristics. Scanning electron microscopic and atomic force microscopic studies show that the microstructures and nanostructures of these two shells are different. Pinna prisms are monocrystalline, whereas Pinctada prisms are not. Moreover, intraprismatic membranes are present only in the Pinctada prisms. The soluble organic matrices extracted from these prisms are acidic, but their bulk compositions differ. Ultraviolet and infrared spectrometries, fluorescence, high pressure liquid chromatography, and electrophoresis show that the sugar-protein ratios and the molecular weights are different. Sulfur is mainly associated with acidic sulfated sugars, not with amino acids, and the role of acidic sulfated sugars is still underestimated. Thus, the simple prism concept is not a relevant model for the biomineralization processes in the calcitic prismatic layer of mollusk shells.

  7. New lucinid bivalves from shallow and deeper water of the Indian and West Pacific Oceans (Mollusca, Bivalvia, Lucinidae

    Directory of Open Access Journals (Sweden)

    John Taylor

    2013-08-01

    Full Text Available Four new species and a new genus of lucinid bivalves are described from shallow and deeper waters in the Indian and West Pacific Oceans. The new genus Scabrilucina (subfamily Lucininae includes the little-known S. victorialis (Melvill, 1899 from the Arabian Sea and S. vitrea (Deshayes, 1844 from the Andaman Sea as well as a new species S. melvilli from the Torres Strait off northeastern Australia. Ferrocina brunei new species (Lucininae was recovered from 60 m near oil drilling activities off Borneo; its anatomy confirmed the presence of symbiotic bacteria. Two unusual deeper water species of Leucosphaerinae are described, both species included in on-going molecular analyses; Gonimyrtea ferruginea from 400–650 m in the southwest Pacific and Myrtina reflexa from 200–825 m off Zanzibar and Madagascar.

  8. Freshwater bivalve shells as archival indicators of metal pollution from a copper-uranium mine in tropical northern Australia.

    Science.gov (United States)

    Markich, Scott J; Jeffree, Ross A; Burke, Patrick T

    2002-03-01

    Freshwater bivalves (Velesunio angasi) were sampled in 1996 from the Finniss River in tropical northern Australia at 10 sites a priori exposed and nonexposed to acid rock drainage (ARD), containing elevated metal concentrations, from the rehabilitated Rum Jungle copper-uranium mine. Secondary ion mass spectrometry (SIMS) was used to measure Cu, Mn, Zn, U, Ni, Co, Pb, and Fe/Ca ratios across the annual shell laminations of the longest-lived bivalves found at each site, with the aim of evaluating the ability of the shells to archive measured annual metal inputs and their temporal patterns. At sites not contaminated by ARD, relatively constant and similar (baseline) SIMS signals were found for all metals in the shell laminations of V. angasi, dating as far back as 1965. At sites contaminated by ARD, relatively constant, but variably elevated, SIMS signals were evident for Cu, Mn, Zn, Ni, and Co in the shell, which extended back to the end of rehabilitation (1986) only. Since rehabilitation, the temporal patterns of Cu, Zn, and Mn observed in the shells at the most contaminated sites reflected those of the measured annual dissolved loads in the surface waters. The average concentrations of Cu, Mn, Zn, Ni, and Co in the shells decreased (3-13-fold) with increasing distance downstream of the mine site, until concentrations characteristic of the noncontaminated sites were reached. This geographic pattern of decline in pollution signal in the shell with increasing distance downstream of the pollution input is consistent with the pattern established for water and sediment chemistry. Overall, the SIMS results support the proposition that the shells of V. angasi can be used as archival indicators of metal pollution in surface waters of the Finniss River over their lifetime.

  9. Biosorption of thorium on the external shell surface of bivalve mollusks: the role of shell surface microtopography.

    Science.gov (United States)

    Zuykov, Michael; Pelletier, Emilien; Saint-Louis, Richard; Checa, Antonio; Demers, Serge

    2012-02-01

    External shell surface (ESS) of bivalve mollusks is known to adsorb various metals dissolved in ambient water in high concentration. It is hypothesized here that the surface microtopography of the thin organic coating layer, periostracum, or calcareous shell (if periostracum was destroyed) plays a major role in the adsorption of actinides on ESS. Thorium (natural alpha-emitter) was used in short-term biosorption experiment with shell fragments of five bivalve mollusks. After a 72 h exposure to Th (~6 kBq L(-1)), thorium concentration was measured on ESS using laser ablation inductively coupled plasma mass spectrometry; the distribution and density of alpha tracks were subsequently visualized by α-track autoradiography. A trend in reduced Th concentrations on the ESS was observed depending upon the species tested: (group 1 ~4000 μg g(-1)) Chlamys islandica (M.), Mercenaria mercenaria (L.), Dreissena polymorpha (P.)>(group 2 ~1200 μg g(-1)) Crassostrea virginica (G.)≫(group 3 ~150 μg g(-1)) Mytilus edulis L. The microtopography of ESS was characterized by scanning electron microscopy revealing the high porosity of the calcareous surface of C. islandica and M. mercenaria, lamellate surface of periostracum in D. polymorpha, uneven but a weakly porous surface of periostracum of C. virginica, and a nearly smooth surface of the periostracum of M. edulis. This work has demonstrated, for the first time, the presence of a strong correlation between concentration of adsorbed Th and ESS microtopography, and the role of the periostracum in this process is discussed.

  10. Heavy metal concentrations in edible bivalves and gastropods available in major markets of the Pearl River Delta

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Molluscs are able to accumulate heavy metals and impose healthhazard to consumers. The main objective of the present study is to investigate the heavy metal concentrations in edible bivalves and gastropods available in major markets of the Pearl River Delta. Fourteen species of edible molluscs were purchased from six markets in Hong Kong and Guangdong Province. The fresh of these biota were tested for their cadmium (Cd), copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), chromium (Cr), antimony (Sb) and tin (Sn)concentrations (based on wet weight). The results indicated that amongst the 14 edible molluscs, only Cd, Pb, Ni, Cr, Sb and Sn concentrations in three species(Ruditapes philippinarum, Perna viridis and Hemifusus tuba) were within the local regulatory limits. Over 60% of bivalve species exceeded maximum permitted levels of Cd (2 μg/g) and Cr (1 μg/g), while over 40% of gastropod species exceeded the maximum levels of Sb (1 μg/g) and Cr(1 μg/g). Most of the samples collected from Hong Kong had significantly higher contents of Pb and Sb, but similar levels of Cd, Cu and Zn when compared with samples collected across the border (p<0.5; p<0.01; p<0.001 respectively). In general, the molluscs purchased in Guangdong markets had higher metal contents than those purchased from the Hong Kong markets. When compared with the Provisional Tolerable Weekly Intake or Maximum Acceptable Daily Load recommended by FAO/WHO Expert Committee on Food Additives, Cd levels of five species (Anadara ferruginea, Pinna pectinata, Chlamys nobilis, Babylonia lutosa and Hemifusus terntanus) and Cr levels of seven species (Anadara ferruginea, Paphia undulata, Pinna pectinata, Babylonia lutosa, Hemifusus terntanus, Cymbium melo and Cipangopaludina chinensis) were higher than both the human daily acceptable limits (for Cd and Cr respectively) and the local regulatory levels (for Cd and Cr respectively).

  11. Integrated assessment of estuarine sediment quality based on a multi-biomarker approach in the bivalve Scrobicularia plana.

    Science.gov (United States)

    Tankoua, O Fossi; Buffet, Pe; Amiard, J C; Berthet, B; Mouneyrac, C; Amiard-Triquet, C

    2013-02-01

    The bivalve Scrobicularia plana has been proposed as a sentinel species for the assessment of estuarine sediment quality. The aim of this study was to test the responsiveness of a set of biomarkers in bivalves originating from a moderately contaminated site (Loire estuary, France) and a comparatively cleaner site (Bay of Bourgneuf, France) used as reference. Temporal fluctuations were examined in animals collected on eight occasions from March 2008 to October 2009 for the determination of biochemical (MTs, GST, AChE), physiological (energy reserves as glycogen and lipids, condition, hepato-somatic and gonado-somatic indices), and behavioural biomarkers (burrowing). Metals in clams were examined with the aim of understanding the variations in MT concentrations. The current findings indicate that among biochemical markers MTs must be used in a precautionary fashion, and comparison with a reference site remains indispensable together with an appreciation of any salinity effects. Clearer responses were obtained for GST activity which contributes to defence against organic compounds. However, any such defence was not sufficient to ensure total protection since a number of impairments were observed at the individual level (burrowing behaviour, condition index, gonado-somatic index). The integrated biomarker response (IBR) illustrated higher levels of stress in clams collected from the Loire estuary compared to those gathered from the reference site at most of the sampling periods. The interpretation of responses involved in the cascade of energetic events (from available food, digestive enzyme activities, energy reserves to condition and reproductive status) is complex but did reveal disturbances in the Loire estuary which is far from being the most contaminated estuary in France and over the world. However, no links can be established between effects at individual and supra-individual levels in organisms in the Loire estuary, even in the case of a small oil spill which

  12. Validation of the flow-through chamber (FTC and steady-state (SS methods for clearance rate measurements in bivalves

    Directory of Open Access Journals (Sweden)

    Poul S. Larsen

    2011-09-01

    To obtain precise and reliable laboratory clearance rate (filtration rate measurements with the ‘flow-through chamber method’ (FTC the design must ensure that only inflow water reaches the bivalve's inhalant aperture and that exit flow is fully mixed. As earlier recommended these prerequisites can be checked by a plot of clearance rate (CR versus increasing through-flow (Fl to reach a plateau, which is the true CR, but we also recommend to plot percent particles cleared versus reciprocal through-flow where the plateau becomes the straight line CR/Fl, and we emphasize that the percent of particles cleared is in itself neither a criterion for valid CR measurement, nor an indicator of appropriate ‘chamber geometry’ as hitherto adapted in many studies. For the ‘steady-state method’ (SS, the design must ensure that inflow water becomes fully mixed with the bivalve's excurrent flow to establish a uniform chamber concentration prevailing at its incurrent flow and at the chamber outlet. These prerequisites can be checked by a plot of CR versus increasing Fl, which should give the true CR at all through-flows. Theoretically, the experimental uncertainty of CR for a given accuracy of concentration measurements depends on the percent reduction in particle concentration (100×P from inlet to outlet of the ideal ‘chamber geomety’. For FTC, it decreases with increasing values of P while for SS it first decreases but then increases again, suggesting the use of an intermediate value of P. In practice, the optimal value of P may depend on the given ‘chamber geometry’. The fundamental differences between the FTC and the SS methods and practical guidelines for their use are pointed out, and new data on CR for the blue mussel, Mytilus edulis, illustrate a design and use of the SS method which may be employed in e.g. long-term growth experiments at constant algal concentrations.

  13. Correlation between POPs in sediment and edible bivalve in the lagoon of Venice and estimation of the daily intake

    Energy Technology Data Exchange (ETDEWEB)

    Raccanelli, S.; Favotto, M. [Consorzio I.N.C.A., Venezia (Italy); Pastres, R. [Univ. of Venice (Italy); Vio, P. [Servizio Igiene Alimenti e Nutrizione, Regione Veneto (Italy)

    2004-09-15

    The lagoon of Venice, which is located in the Northern Adriatic Sea, is the largest Italian Lagoon, covering an area of about 550 km2. Its average depth is about 0.7 m, but its morphology is characterized by the presence of large shallow areas and by a network of deeper channels. As can be seen in Fig. 1, three narrow inlets connect the lagoon to the Adriatic Sea. The lagoon is conventionally partitioned into three sub-basins, which are separated by two watershed, along which the tidal velocity are low. In the last century the area of Porto Marghera, opposite the city of Venice, was converted into one of largest industrial area in Europe. As a result of the industrial activities, dioxin and dioxin-like compounds, as well as other classes of pollutants, were released into the environment. The lagoon sediment represented the main sink for this contaminants: in fact, concentrations higher than 2500 ng(I-TE)/kg were found in the sediment in the channels of the industrial area. At present, Tapes philippinarum is the target of an intensive fishing activity, which severely damages the lagoon sediment and the benthic community. Even though fishing is not allowed nearby the Industrial area, illegal catches of contaminated clams are still being commercialized. As a consequence, the risk for health of regular consumer of this bivalve should be estimated. In order to assess the risk and to reassure the consumers, In the year 2002, the main local fishermen association, CoVeAlLa, has set up a monitoring program of PCDD/F, PCB dioxinlike and HCB both in the sediment and in the flesh of the edible bivalve Tapes philippinarum. In this paper, we present and discuss the results which were obtained in the year 2003.

  14. Antioxidant, genotoxic and lysosomal biomarkers in the freshwater bivalve (Unio pictorum) transplanted in a metal polluted river basin.

    Science.gov (United States)

    Guidi, Patrizia; Frenzilli, Giada; Benedetti, Maura; Bernardeschi, Margherita; Falleni, Alessandra; Fattorini, Daniele; Regoli, Francesco; Scarcelli, Vittoria; Nigro, Marco

    2010-10-01

    The freshwater painter's mussel (Unio pictorum) was used as sentinel species to assess the chemical disturbance in an Italian river (the river Cecina) characterized by elevated levels of trace metals of both natural and anthropogenic origin. Organisms were transplanted for 4 weeks in different locations of the river basin and the bioaccumulation of metals was integrated with a wide battery of biomarkers consisting of oxidative, genotoxic and lysosomal responses. Such parameters included the levels of individual antioxidants (catalase, glutathione-S-transferases, glutathione reductase, Se-dependent and Se-independent glutathione peroxidases, total glutathione), the total oxyradical scavenging capacity (TOSC), metallothionein-like proteins, the assessment of DNA integrity, chromosomal damages and lysosomal membrane stability. Elevated levels of several metals were measured in sediments, but the relatively low tissue concentrations suggested a moderate bioaccumulation, possibly due to a high excretion efficiency, of U. pictorum and/or to a limited bioavailability of these elements, partly deriving from erosion of bedrocks. Among antioxidant responses, those based on glutathione metabolism and the activity of catalase were mostly affected in bivalves showing a significant accumulation of arsenic, mercury and/or nickel. In these specimens, the content of glutathione and the activities of glutathione reductase and glutathione peroxidases (H2O2) were respectively 9-, 6- and 4-fold lower than in controls, while a 3-fold increase was observed for catalase. Despite some differences in the response of individual antioxidants, a significant reduction of the capability to neutralize peroxyl radicals was observed in bivalves caged in all the impacted sites of the river basin; these organisms also exhibited a significant impairment at the DNA, chromosomal and lysosomal levels. Considering the mild contamination gradient in the investigated area, the overall results suggested that

  15. Evaluation of the threat of marine CO{sub 2} leakage-associated acidification on the toxicity of sediment metals to juvenile bivalves

    Energy Technology Data Exchange (ETDEWEB)

    Basallote, M. Dolores, E-mail: dolores.basallote@uca.es [Cátedra UNESCO/UNITWIN WiCop, Departamento de Química-Física, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Polígono Río San Pedro s/n, 11510 Puerto Real, Cádiz (Spain); Rodríguez-Romero, Araceli [Departamento de Ecología y Gestión Costera, Instituto de Ciencias Marinas de Andalucía (CSIC), Campus Río San Pedro, 11510 Puerto Real, Cádiz (Spain); De Orte, Manoela R.; Del Valls, T. Ángel; Riba, Inmaculada [Cátedra UNESCO/UNITWIN WiCop, Departamento de Química-Física, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Polígono Río San Pedro s/n, 11510 Puerto Real, Cádiz (Spain)

    2015-09-15

    Highlights: • Short-term tests using juveniles of bivalves to study the effects of CO{sub 2} dissolved. • CO{sub 2} causes effects if the threshold concentration of the organism is overlapped. • Flows of escaped CO{sub 2} would affect the geochemical composition of sediment–seawater. • CO{sub 2}-induced acidification would affect differently to marine sediment toxicity. - Abstract: The effects of the acidification associated with CO{sub 2} leakage from sub-seabed geological storage was studied by the evaluation of the short-term effects of CO{sub 2}-induced acidification on juveniles of the bivalve Ruditapes philippinarum. Laboratory scale experiments were performed using a CO{sub 2}-bubbling system designed to conduct ecotoxicological assays. The organisms were exposed for 10 days to elutriates of sediments collected in different littoral areas that were subjected to various pH treatments (pH 7.1, 6.6, 6.1). The acute pH-associated effects on the bivalves were observed, and the dissolved metals in the elutriates were measured. The median toxic effect pH was calculated, which ranged from 6.33 to 6.45. The amount of dissolved Zn in the sediment elutriates increased in parallel with the pH reductions and was correlated with the proton concentrations. The pH, the pCO{sub 2} and the dissolved metal concentrations (Zn and Fe) were linked with the mortality of the exposed bivalves.

  16. Experimental-study of the interactions between a natural C-14 radiolabeled sediment and a deposit-feeding bivalve : Abra alba

    OpenAIRE

    Amouroux, Jm; Gremare, A.; Cahet, G.

    1991-01-01

    Changes of radioactivity in a natural C-14 labelled sediment were monitored over a 120-hour period in the presence and in the absence of the deposit-feeding bivalve Abra alba. In both cases, the sediment showed great instability during the first ten hours of the experiment. The consequences of this result on the experimental protocol used for the study of the interactions between natural sediments and deposit-feeders are discussed. In controls, the instability is produced by an initial decrea...

  17. Interactive effects of elevated temperature and CO2 levels on energy metabolism and biomineralization of marine bivalves Crassostrea virginica and Mercenaria mercenaria.

    Science.gov (United States)

    Ivanina, Anna V; Dickinson, Gary H; Matoo, Omera B; Bagwe, Rita; Dickinson, Ashley; Beniash, Elia; Sokolova, Inna M

    2013-09-01

    The continuing increase of carbon dioxide (CO2) levels in the atmosphere leads to increases in global temperatures and partial pressure of CO2 (PCO2) in surface waters, causing ocean acidification. These changes are especially pronounced in shallow coastal and estuarine waters and are expected to significantly affect marine calcifiers including bivalves that are ecosystem engineers in estuarine and coastal communities. To elucidate potential effects of higher temperatures and PCO2 on physiology and biomineralization of marine bivalves, we exposed two bivalve species, the eastern oysters Crassostrea virginica and the hard clams Mercenaria mercenaria to different combinations of PCO2 (~400 and 800μatm) and temperatures (22 and 27°C) for 15weeks. Survival, bioenergetic traits (tissue levels of lipids, glycogen, glucose and high energy phosphates) and biomineralization parameters (mechanical properties of the shells and activity of carbonic anhydrase, CA) were determined in clams and oysters under different temperature and PCO2 regimes. Our analysis showed major inter-species differences in shell mechanical traits and bioenergetics parameters. Elevated temperature led to the depletion of tissue energy reserves indicating energy deficiency in both species and resulted in higher mortality in oysters. Interestingly, while elevated PCO2 had a small effect on the physiology and metabolism of both species, it improved survival in oysters. At the same time, a combination of high temperature and elevated PCO2 lead to a significant decrease in shell hardness in both species, suggesting major changes in their biomineralization processes. Overall, these studies show that global climate change and ocean acidification might have complex interactive effects on physiology, metabolism and biomineralization in coastal and estuarine marine bivalves.

  18. Seasonal variation of bivalve larvae on an exposed sandy beach on Kashima-nada: Tips for the sandy beach recruitment process

    Science.gov (United States)

    Sawada, Hideki; Saito, Hajime; Adachi, Kumiko; Toyohara, Haruhiko

    2011-02-01

    Bivalves are often the dominant macrobenthos species in exposed sandy beach environments. However, our understanding of their recruitment processes before post-settlement stages on sandy beaches with highly energetic environments is incomplete. To clarify the characteristics of the free-swimming planktonic stage that affects recruitment efficiency in sandy shore ecosystems, we investigated the temporal (weekly-biweekly) variation of bivalve planktonic larval concentration coupled with oceanographic conditions on an exposed sandy shore on the sea of Kashima-nada, Japan, from summer 2003 to autumn 2005. Larvae were observed throughout the year, but the surge of larval concentration composed of sandy beach and sessile bivalves occurred most prominently in summer, from August to September. The peak concentration of larvae during this season was more than 1000 times higher than in other seasons. The larval concentration was positively correlated with water temperature and northward wind velocity and negatively correlated with each of the nutrient concentrations. On the other hand, chlorophyll a concentration and salinity seemed to have little effect on the larval concentration. Based on this fundamental knowledge, further investigations about planktonic larvae in sandy beaches are needed.

  19. Constraining riverine δ13C-DIC using Late Cretaceous and Early Paleogene freshwater bivalve mollusks (Unionoidea) form Montana

    Science.gov (United States)

    Gillikin, D. P.; Goodwin, D. H.; Davidson, M.; Hartman, J.

    2014-12-01

    Interpretation of carbon isotope variation in freshwater unionoid mollusk shells (δ13CSHELL) is not straightforward because of the variable contributions of metabolic (i.e., food) and dissolved inorganic carbon (DIC). Bivalve shells typically contain between 0 and 50% metabolic carbon (CM), which has a δ13C value close to the animal's food source. In marine systems, the food source (usually phytoplankton) has a δ13C value typically around -20 ‰ and a d13CDIC value around ~0 ‰. In freshwater systems, these numbers can vary considerably, with food sources ranging from -35 to -10 ‰. Typically, δ13C-DIC values range between -25 to 0‰ and are dependent on numerous factors; carbonate weathering and equilibrium with the atmosphere typically leading to high values and respiration of organic matter and oxidation of methane leading to lower values. Therefore, δ13C-DIC values reflect numerous processes occurring in the watershed. Nevertheless, here we suggest δ13CSHELL values can constrain the lower bounds of riverine δ13C-DIC values, despite the influence of CM. The metabolic end-member δ13C value is typically lower than the DIC end member and consequently will lead to higher calculated δ13C-DIC when using δ13CSHELL values. Therefore, if the CM fraction is set to 0 %, δ13CSHELL values will provide the lowest possible riverine δ13C-DIC values (after accounting for fractionation). Applying this method to modern shells from waters with known δ13C-DIC values (ranging from -3.2 to -12.8 ‰) results in calculated δ13C-DIC values from -6.0 to -12.4 ‰, which is close to measured DIC data from the waters in which the mussel grew. This can then in turn be applied to well-preserved fossil shells. Freshwater unionoid shells from the uppermost Cretaceous Hell Creek Formation and the lower Paleogene Fort Union Formation are exceptionally well preserved. Applying this method to these shells results in δ13C-DIC values ranging from -6 to -11‰, which is consistent

  20. Effects of depuration on the element concentration in bivalves: Comparison between sympatric Ruditapes decussatus and Ruditapes philippinarum

    Science.gov (United States)

    Freitas, R.; Ramos Pinto, L.; Sampaio, M.; Costa, A.; Silva, M.; Rodrigues, A. M.; Quintino, V.; Figueira, E.

    2012-09-01

    Organisms living in coastal ecosystems are frequently subjected to anthropogenic pressures such as metals. Metals, especially those not required for metabolic activity (e.g. mercury, lead and cadmium) can be toxic even at quite low concentrations not only to organisms that accumulate them, but also to their consumers. Throughout the world, Ruditapes decussatus and Ruditapes philippinarum have been successfully commercialised for human consumption and for monitoring environmental conditions such as contamination. These two clam species share similar habitats and requirements, successfully competing both in the natural environment and in aquaculture farms. Because differences in metal accumulation may exist between R. decussatus and R. philippinarum, different risks to public health may overcome as well as distinct ecological implications. The effect of depuration on the metal burden and biochemical status of both clams species may also diverge and since the information available is subjective and scarce, the aims of the present study were to: 1) assess the total metal accumulation and intracellular partitioning, at natural conditions, in the two clam species collected at the same site; 2) evaluate the effect of depuration as a mean of reducing the levels of distinct elements, assessing also the effect of depuration time (2 and 7 days); 3) investigate the efficiency of depuration by biochemical status of the two bivalve species, evaluating changes in lipid peroxidation and activity of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and of glutathione S-transferase (GST). Metal chelation by metallothioneins (MTs) was also determined. The results obtained showed that concentration of elements in clams was low, presenting very similar concentration levels for all elements. The present work further demonstrated that the total element concentration decreased in the shorter depuration period (2 days) and that R. decussatus and R. philippinarum partitioned

  1. A humidity sensitive two-dimensional tunable amorphous photonic structure in the outer layer of bivalve ligament from Sunset Siliqua

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Weigang, E-mail: abczwg15@163.com [College of Materials and Chemical Engineering, Chuzhou University, Chuzhou 239000 (China); Zhang, Gangsheng [College of Material Science and Technology, Guangxi University, Nanning 530004 (China)

    2015-07-01

    A humidity sensitive two-dimensional tunable amorphous photonic structure (2D TAPS) in the outer layer of bivalve ligament from Sunset Siliqua (OLLS) was reported in this paper. The structural color and microstructure of OLLS were investigated by reflection spectra and scanning electron microscopy, respectively. The results indicate that the reflection peak wavelength of the wet OLLS blue-shifts from 454 nm to 392 nm with the increasing of air drying time from 0 to 40 min, while the reflectivity decreases gradually and vanishes at last, relevant color changes from blue to black background color. The structural color in the OLLS is produced by a two-dimensional amorphous photonic structure consisting of aligned protein fibers, in which the diameter of protein fiber and the inter-fiber spacing are 101 ± 12 nm. Water can reversibly tune the reflection peak wavelength and reflectivity of this photonic structure, and the regulation achieved through dynamically tuning the interaction between inter-fiber spacing and average refractive index. - Highlights: • A humidity sensitive two-dimensional tunable amorphous photonic structure • Water can reversibly tune the reflection peak wavelength and reflectivity of this photonic structure. • This photonic structure may yield very useful template for artificial structures.

  2. A humidity sensitive two-dimensional tunable amorphous photonic structure in the outer layer of bivalve ligament from Sunset Siliqua.

    Science.gov (United States)

    Zhang, Weigang; Zhang, Gangsheng

    2015-01-01

    A humidity sensitive two-dimensional tunable amorphous photonic structure (2D TAPS) in the outer layer of bivalve ligament from Sunset Siliqua (OLLS) was reported in this paper. The structural color and microstructure of OLLS were investigated by reflection spectra and scanning electron microscopy, respectively. The results indicate that the reflection peak wavelength of the wet OLLS blue-shifts from 454 nm to 392 nm with the increasing of air drying time from 0 to 40 min, while the reflectivity decreases gradually and vanishes at last, relevant color changes from blue to black background color. The structural color in the OLLS is produced by a two-dimensional amorphous photonic structure consisting of aligned protein fibers, in which the diameter of protein fiber and the inter-fiber spacing are 101 ± 12 nm. Water can reversibly tune the reflection peak wavelength and reflectivity of this photonic structure, and the regulation achieved through dynamically tuning the interaction between inter-fiber spacing and average refractive index.

  3. A humidity sensitive two-dimensional tunable amorphous photonic structure in the bivalve ligament of Meretrix linnaeus.

    Science.gov (United States)

    Zhang, Weigang; Zhang, Gangsheng

    2015-12-01

    A humidity sensitive two-dimensional tunable amorphous photonic structure (2D TAPS) in the bivalve ligament of Meretrix linnaeus (LML) was reported in this paper. The structural color and microstructure of LML were investigated by reflection spectra and scanning electron microscopy, respectively. The results indicate that the LML has complex structural colors from blue to orange in the wet state from ventral to dorsal, which are derived from the aragonite fiber diameter increases continuously from ventral to dorsal of the ligament. The reflection peak wavelength of the wet LML can blue-shift from 522 nm to 480 nm with the air drying time increased from 0 to 60 min, while the reflectivity decreases gradually and only a weak reflection peak at last, relevant color changes from green to light blue. The structural color in the LML is produced by a two-dimensional amorphous photonic structure consists of aligned aragonite fibers and proteins, in which the diameters of the aragonite fiber and the inter-fiber spacing are 104±11 nm and 126±16 nm, respectively. Water can reversibly tune the reflection peak wavelength and reflectivity of this photonic structure, and the regulation achieved through dynamically tune the degree of order and lattice constant of the ligament in the different wet states.

  4. Borniopsis mortoni sp. n. (Heterodonta, Galeommatoidea, Galeommatidae sensu lato), a new bivalve commensal with a synaptid sea cucumber from Japan

    Science.gov (United States)

    Goto, Ryutaro; Ishikawa, Hiroshi

    2016-01-01

    Abstract The Galeommatoidea is a bivalve superfamily that exhibits high species diversity in shallow waters. Many members of this superfamily are associated commensally with burrowing marine invertebrates in benthic sediments. The genus Borniopsis is known only from eastern Asia and exhibits high host diversity (e.g., mantis shrimps, crabs, holothurians, sipunculans and echiurans). A new species, Borniopsis mortoni sp. n., is described from mud flats at the mouth of the Souzu River, southwestern Shikoku Island, Japan. This species has elongate-ovate shells covered by a tan to dark brown periostracum, and lives attached by both its foot and byssal threads to the body surface of the synaptid sea cucumber Patinapta ooplax. Several individuals of Borniopsis mortoni are often found on the same host, but sometimes more than 10 individuals can occur together. Borniopsis mortoni is one of the smallest species in this genus. Probably, its small body size is an adaptation to the mode of life in a narrow host burrow. Until now, only two other Borniopsis species were known to have commensal associations with synaptids. Thus, this is the third example of a synaptid-associated species from this genus. In addition, we briefly review the galeommatoideans commensal with apodid sea cucumbers. PMID:27667939

  5. Determination of the toxic variability of lipophilic biotoxins in marine bivalve and gastropod tissues treated with an industrial canning process.

    Science.gov (United States)

    García, Carlos; Oyaneder-Terrazas, Javiera; Contreras, Cristóbal; Del Campo, Miguel; Torres, Rafael; Contreras, Héctor R

    2016-11-01

    Contamination of shellfish with lipophilic marine biotoxins (LMB), pectenotoxins (PTXs), yessotoxins (YTXs) and okadaic acid (OA) toxin groups in southern Chile is a constant challenge for the development of miticulture considering the high incidence of toxic episodes that tend to occur. This research is focused on using methodologies for assessing the decrease in toxins of natural resources in Chile with high value, without altering the organoleptic properties of the shellfish. The species were processed through steaming (1 min at 121°C) and subsequent canning (5 min at 121°C). Changes in the profiles of toxins and total toxicity levels of LMB in endemic bivalves and gastropods were determined using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The total reduction of toxicity (≈ 15%) was not related to the destruction of the toxin, but rather to the loss of LMB on removing the shells and packing media of canned products (***p < 0.001). Industrial processing of shellfish reduces LMB contents by up to 15% of the total initial contents, concomitant only with the interconversion of PTX-group toxins into PTX-2sa. In soft bottom-dwelling species with toxicities beyond the standard for safe human consumption (≥ 160 μg OA-eq kg(-)(1)), toxicity can be reduced to safe levels through industrial preparation procedures.

  6. Complete sequences of the highly rearranged molluscan mitochondrial genomes of the scaphopod graptacme eborea and the bivalve mytilus edulis

    Energy Technology Data Exchange (ETDEWEB)

    Boore, Jeffrey L.; Medina, Monica; Rosenberg, Lewis A.

    2004-01-31

    We have determined the complete sequence of the mitochondrial genome of the scaphopod mollusk Graptacme eborea (Conrad, 1846) (14,492 nts) and completed the sequence of the mitochondrial genome of the bivalve mollusk Mytilus edulis Linnaeus, 1758 (16,740 nts). (The name Graptacme eborea is a revision of the species formerly known as Dentalium eboreum.) G. eborea mtDNA contains the 37 genes that are typically found and has the genes divided about evenly between the two strands, but M. edulis contains an extra trnM and is missing atp8, and has all genes on the same strand. Each has a highly rearranged gene order relative to each other and to all other studied mtDNAs. G. eborea mtDNA has almost no strand skew, but the coding strand of M. edulis mtDNA is very rich in G and T. This is reflected in differential codon usage patterns and even in amino acid compositions. G. eborea mtDNA has fewer non-coding nucleotides than any other mtDNA studied to date, with the largest non-coding region being only 24 nt long. Phylogenetic analysis using 2,420 aligned amino acid positions of concatenated proteins weakly supports an association of the scaphopod with gastropods to the exclusion of Bivalvia, Cephalopoda, and Polyplacophora, but is generally unable to convincingly resolve the relationships among major groups of the Lophotrochozoa, in contrast to the good resolution seen for several other major metazoan groups.

  7. Adaptation of the bivalve embryotoxicity assay for the high throughput screening of emerging contaminants in Mytilus galloprovincialis.

    Science.gov (United States)

    Fabbri, Rita; Montagna, Michele; Balbi, Teresa; Raffo, Enrico; Palumbo, Franca; Canesi, Laura

    2014-08-01

    Emerging contaminants (such as Endocrine disrupting chemicals-EDCs, brominated and perfluorinated compounds-BFRs and PFCs, pharmaceuticals) are chemicals currently not included in regulatory monitoring programs, and whose fate and biological impacts are poorly understood. Assessment of ecosystem health with respect to these chemicals is of particular concern also in the marine environment: in this respect, data on the effects on early life stages are important to establish the sensitivity of marine species. In this work, the acute (48 h) bivalve embryo toxicity test was applied for screening the developmental effects of different emerging contaminants in the Mediterranean mussel Mytilus galloprovincialis. The assay was adapted to 96-microwell plates, and standardized in order to obtain to normal D-shaped larvae with acceptability of test results based on negative control and positive control (copper) comparable with those reported in literature for Mytilus spp. The effects of different model compounds representative of EDCs (Nonylphenol-NP and Bisphenol A-BPA), BFRs (Tetrabromobisphenol A-TBBPA), PFCs (perfluorooctanoid acid-PFOA and perfluorooctane sulphonate-PFOAS) and pharmaceuticals (Ibuprofen-IBU, Diclofenac-DCF, Bezafibrate-BEZA) in a wide concentration range (0.01-0.1-1-10-100-1000 μg/L) were evaluated. The assay proved as a sensitive tool for high throughput screening of emerging contaminants in a marine species, leading to production of significant amounts of data that may be useful for regulatory purposes.

  8. Marine bivalve shell geochemistry and ultrastructure from modern low pH environments: environmental effect versus experimental bias

    Science.gov (United States)

    Hahn, S.; Rodolfo-Metalpa, R.; Griesshaber, E.; Schmahl, W. W.; Buhl, D.; Hall-Spencer, J. M.; Baggini, C.; Fehr, K. T.; Immenhauser, A.

    2012-05-01

    Bivalve shells can provide excellent archives of past environmental change but have not been used to interpret ocean acidification events. We investigated carbon, oxygen and trace element records from different shell layers in the mussels Mytilus galloprovincialis combined with detailed investigations of the shell ultrastructure. Mussels from the harbour of Ischia (Mediterranean, Italy) were transplanted and grown in water with mean pHT 7.3 and mean pHT 8.1 near CO2 vents on the east coast of the island. Most prominently, the shells recorded the shock of transplantation, both in their shell ultrastructure, textural and geochemical record. Shell calcite, precipitated subsequently under acidified seawater responded to the pH gradient by an in part disturbed ultrastructure. Geochemical data from all test sites show a strong metabolic effect that exceeds the influence of the low-pH environment. These field experiments showed that care is needed when interpreting potential ocean acidification signals because various parameters affect shell chemistry and ultrastructure. Besides metabolic processes, seawater pH, factors such as salinity, water temperature, food availability and population density all affect the biogenic carbonate shell archive.

  9. Marine bivalve shell geochemistry and ultrastructure from modern low pH environments: environmental effect versus experimental bias

    Directory of Open Access Journals (Sweden)

    S. Hahn

    2012-05-01

    Full Text Available Bivalve shells can provide excellent archives of past environmental change but have not been used to interpret ocean acidification events. We investigated carbon, oxygen and trace element records from different shell layers in the mussels Mytilus galloprovincialis combined with detailed investigations of the shell ultrastructure. Mussels from the harbour of Ischia (Mediterranean, Italy were transplanted and grown in water with mean pHT 7.3 and mean pHT 8.1 near CO2 vents on the east coast of the island. Most prominently, the shells recorded the shock of transplantation, both in their shell ultrastructure, textural and geochemical record. Shell calcite, precipitated subsequently under acidified seawater responded to the pH gradient by an in part disturbed ultrastructure. Geochemical data from all test sites show a strong metabolic effect that exceeds the influence of the low-pH environment. These field experiments showed that care is needed when interpreting potential ocean acidification signals because various parameters affect shell chemistry and ultrastructure. Besides metabolic processes, seawater pH, factors such as salinity, water temperature, food availability and population density all affect the biogenic carbonate shell archive.

  10. Feeding behavior of the invasive bivalve Limnoperna fortunei (Dunker, 1857 under exposure to toxic cyanobacteria Microcystis aeruginosa

    Directory of Open Access Journals (Sweden)

    V Gazulha

    Full Text Available The aim of this study was to test the effects of cyanobacteria toxicity on feeding behavior of the golden mussel Limnoperna fortunei. First, it was tested the hypothesis that L. fortunei preferentially graze on non-toxic phytoplankton and reject toxic cyanobacteria. Second, it was tested the hypothesis that toxic cyanobacteria negatively affect feeding and survival of L. fortunei. The present study is the first to evaluate the effects of toxic cyanobacteria on L. fortunei feeding and survival. In the short-term grazing, golden mussel filtration rates were evaluated in the presence of toxic and non-toxic strains of cyanobacteria Microcystis aeruginosa, and non-toxic phytoplankton Nitzschia palea. Highest filtration rates were registered when mussels fed on Nitzschia. Despite that, golden mussel expelled Nitzschia cells in large quantities and preferentially ingested Microcystis cells, both toxic and non-toxic strains. In the long-term grazing, mussels were exposed to toxic and non-toxic strains of Microcystis during 5 days. Filtration rates were not significantly different for toxic and non-toxic Microcystis throughout exposure period. The results have demonstrated cyanobacteria toxicity is not the main factor influencing L. fortunei feeding behavior. Survival of L. fortunei feeding on toxic cyanobacteria shows the potential of this invasive bivalve as a vector to the transference of cyanotoxins to higher trophic levels.

  11. Interactive effects of metal contamination and pathogenic organisms on the introduced marine bivalve Ruditapes philippinarum in European populations

    Energy Technology Data Exchange (ETDEWEB)

    Paul-Pont, Ika, E-mail: i.paulpont@epoc.u-bordeaux1.f [Universite Bordeaux 1, UMR 5805 CNRS, Station Marine d' Arcachon, place du Dr. Peyneau, Arcachon 33120 (France); Montaudouin, Xavier de; Gonzalez, Patrice; Jude, Florence; Raymond, Natalie [Universite Bordeaux 1, UMR 5805 CNRS, Station Marine d' Arcachon, place du Dr. Peyneau, Arcachon 33120 (France); Paillard, Christine [Universite de Bretagne Occidentale-IUEM, LEMAR UMR 6539 CNRS, Place Nicolas Copernic, Technopole Brest Iroise, 29280 Plouzane (France); Baudrimont, Magalie [Universite Bordeaux 1, UMR 5805 CNRS, Station Marine d' Arcachon, place du Dr. Peyneau, Arcachon 33120 (France)

    2010-11-15

    In natural environment, marine organisms are concomitantly exposed to pollutants and multiple disease agents resulting in detrimental interactions. The present study evaluated interactive effects of metal contamination (cadmium) and pathogenic organisms (trematode parasites Himasthla elongata and pathogenic bacteria Vibrio tapetis) singularly and in combination on the bivalve Ruditapes philippinarum, an introduced species to Europe, under laboratory controlled conditions. After 7 days, metal bioaccumulation and pathogen load were analyzed as well as metallothionein (MT) response and hemocyte concentrations and activities. Results showed that infection by opportunistic pathogens affects metal accumulation, leading to maximal Cd accumulation in co-infected clams. Among stressors only V. tapetis induced significant effects on immune parameters whereas a particular interaction 'trematode-bacteria' was shown on MT responses. Despite low trematode infection in agreement with the resistant status of R. philippinarum to these macroparasites, significant interaction with bacteria and metal occurred. Such results highlight the necessity of taking pathogens into account in ecotoxicological studies. - Co-infection by opportunistic pathogens affects metal accumulation and some defense-related activities in the Manila clam Ruditapes philippinarum.

  12. Re-emergence of Vibrio tubiashii in bivalve shellfish aquaculture: severity, environmental drivers, geographic extent and management.

    Science.gov (United States)

    Elston, Ralph A; Hasegawa, Hiroaki; Humphrey, Karen L; Polyak, Ildiko K; Häse, Claudia C

    2008-11-20

    During 2006 and 2007, we documented the re-emergence of severe episodes of vibriosis caused by Vibrio tubiashii in shellfish hatcheries on the west coast of North America. Lost larval and juvenile production included 3 previously undescribed hosts, Pacific (Crassostrea gigas) and Kumamoto (C. sikamea) oysters and geoduck clams Panope abrupta, with a 2007 decline in larval oyster production of approximately 59% in one hatchery. Losses of larval and juvenile bivalves were linked to V. tubiashii blooms in the coastal environment, which were associated with the apparent mixing of unusually warm surface seawater and intermittently upwelled cooler, nutrient- and Vibrio spp.- enriched seawater. The ocean temperature elevation anomaly in 2007 was not clearly linked to an El Niño event, as was a similar episode in 1998. Concentrations of the dominant shellfish-pathogenic vibrios were as high as 1.6 x 10(5) cfu ml(-1) in the cold, upwelled water. The bacteria possessed the genes coding for a protease and hemolysin described for V. tubiashii, and pathogenic isolates secreted these peptides. Lesions resulting from a classic invasive disease and a toxigenic noninvasive disease occurred in oyster and geoduck clam larvae. Management and prevention require reduction of incoming concentrations of the bacteria, reduction of contamination in water and air supplies and in stock chemical solutions, removal of bacterial toxins, and interruption of the cycle of bacterial amplification in the hatchery and in microalgal food supplies.

  13. Polychlorinated biphenyls, organochlorine pesticides and trace metals in cultured and harvested bivalves from the eastern Adriatic coast (Croatia).

    Science.gov (United States)

    Milun, Vesna; Lušić, Jelena; Despalatović, Marija

    2016-06-01

    Polychlorinated biphenyls, organochlorine pesticides and trace metals were determined in tissues of bivalve molluscs (Mytilus galloprovincialis, Ostrea edulis, Venus verrucosa, Arca noae and Callista chione), collected from 11 harvesting and 2 cultured locations along the eastern Adriatic coast, in May and November 2012. Concentrations (ng g(-1) dry weight) of organochlorines ranged from 1.53 to 21.1 for PCBs and 0.68 to 5.21 for p,p'-DDTs. HCB, lindane, heptachlor and aldrin-like compounds were found in lower levels or were not detected. Metal concentrations (mg kg(-1) dry weight) ranged from 0.23 to 4.03 for Cd, 0.87-3.43 for Cr, 3.69-202.3 for Cu, 0.06-0.26 for HgT, 0.62-9.42 for Ni, 0.95-4.64 for Pb, and 55.76-4010.3 for Zn. Established organochlorine and trace metal levels were lower than the maximum allowable levels in seafood set by the European Commission.

  14. Borniopsis mortoni sp. n. (Heterodonta, Galeommatoidea, Galeommatidae sensu lato, a new bivalve commensal with a synaptid sea cucumber from Japan

    Directory of Open Access Journals (Sweden)

    Ryutaro Goto

    2016-09-01

    Full Text Available The Galeommatoidea is a bivalve superfamily that exhibits high species diversity in shallow waters. Many members of this superfamily are associated commensally with burrowing marine invertebrates in benthic sediments. The genus Borniopsis is known only from eastern Asia and exhibits high host diversity (e.g., mantis shrimps, crabs, holothurians, sipunculans and echiurans. A new species, Borniopsis mortoni sp. n., is described from mud flats at the mouth of the Souzu River, southwestern Shikoku Island, Japan. This species has elongate-ovate shells covered by a tan to dark brown periostracum, and lives attached by both its foot and byssal threads to the body surface of the synaptid sea cucumber Patinapta ooplax. Several individuals of B. mortoni are often found on the same host, but sometimes more than 10 individuals can occur together. Borniopsis mortoni is one of the smallest species in this genus. Probably, its small body size is an adaptation to the mode of life in a narrow host burrow. Until now, only two other Borniopsis species were known to have commensal associations with synaptids. Thus, this is the third example of a synaptid-associated species from this genus. In addition, we briefly review the galeommatoideans commensal with apodid sea cucumbers.

  15. Influence of a step-change in metal exposure (Cd, Cu, Zn) on metal accumulation and subcellular partitioning in a freshwater bivalve, Pyganodon grandis: A long-term transplantation experiment between lakes with contrasting ambient metal levels

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Sophie [INRS-Eau, Terre et Environnement, Université du Québec, 490 de la Couronne, Québec, QC G1K 9A9 (Canada); Bonneris, Emmanuelle [INRS-Eau, Terre et Environnement, Université du Québec, 490 de la Couronne, Québec, QC G1K 9A9 (Canada) and Bayer S.A.S., Bayer CropScience, 16 Rue Jean-Marie Leclair, CP 90106, F 69266 Lyon Cedex 09 (France); Michaud, Annick [INRS-Eau, Terre et Environnement, Université du Québec, 490 de la Couronne, Québec, QC G1K 9A9 (Canada) and Direction des Évaluations environnementales, Ministère du Développement durable, de l’Environnement et des Parcs, 675, boul. René-Lévesque Est, 6e étage, Québec, QC G1R 5V7 (Canada); Pinel-Alloul, Bernadette [Groupe de Recherche Interuniversitaire en Limnologie et Environnement Aquatique (GRIL), Département de Sciences Biologiques, Université de Montréal, C.P. 6128, Montréal, QC H3C 3J7 (Canada); Campbell, Peter G.C., E-mail: peter.campbell@ete.inrs.ca [INRS-Eau, Terre et Environnement, Université du Québec, 490 de la Couronne, Québec, QC G1K 9A9 (Canada)

    2013-05-15

    Highlights: ? We transferred freshwater bivalves from a reference lake to a Cd and Zn contaminated lake. ? Changes in metal accumulation and subcellular partitioning were followed over time (up to 860 d). ? Metal detoxification strategies differed between target organs (gills vs. digestive gland). ? The ability to handle Cd is inherent in P. grandis, not a trait acquired after long-term adaptation. -- Abstract: The objective of the present field experiment was to identify detoxification responses in the gills and digestive gland of a freshwater unionid bivalve, Pyganodon grandis, subjected to a step-change in metal exposure. Adult bivalves were transferred from a reference site (Lake Opasatica) and a metal-contaminated lake (Lake Héva) to a second contaminated lake (Lake Vaudray) in northwestern Quebec, Canada. Changes in organ metal concentrations, in the subcellular distribution of metals and in metallothionein concentrations were followed over time (t = 0, 132, (400) and 860 days). At each collection time and for each bivalve, the gills and digestive gland were excised and gently homogenized; six sub-cellular fractions were separated by differential centrifugation and analyzed for their Cd, Cu and Zn content, and metallothionein was quantified independently. Metal detoxification strategies were shown to differ between target organs: in the gills, incoming metals were sequestered largely in the granules, whereas in the digestive gland the same metals primarily accumulated in the cytosol, in the metallothionein-like protein fraction. These metal-handling strategies, as employed by the metal-naïve bivalves originating in the reference lake, closely resemble those identified in free-living P. grandis chronically exposed in the metal-contaminated lake, suggesting that the ability to handle incoming metals (Cd in particular) is inherent in P. grandis and is not a trait acquired after long-term adaptation of the bivalve to metal-contaminated environments. The

  16. Temperature dependent larval occurrence and spat settlement of the invasive brackish water bivalve Mytilopsis leucophaeata (Conrad, 1831) (Dreissenidae)

    Science.gov (United States)

    van der Gaag, M.; van der Velde, G.; Wijnhoven, S.; Rajagopal, S.

    2014-03-01

    Mytilopsis leucophaeata, an invasive bivalve species, causes fouling problems by settling on submerged constructions and in cooling water circuits in brackish water. To predict spat fall we studied the larval occurrence and settlement of this species in the brackish Noordzeekanaal canal in the Netherlands for several years (1989-1992), while measuring water temperature, salinity and chlorophyll a levels. Larvae were collected monthly by means of a plankton net drawn across the whole width of the canal. Settled spat were collected from PVC panels exposed for one month. Larvae first appeared in May or June, and reached maximum numbers in June or July, before disappearing in October, November or even December. The larval period started at a water temperature of 14 °C, reached maximum numbers at 19-23 °C and ended when it fell below 9 °C. No larvae were observed anymore until the temperature rose to 14 °C in the spring of the next year. Spat fall (June-November) was related to the water temperature in April. If the water temperature in April was lower than 12.5 °C, spat fall started in July, while if temperature was already higher in April, it started a month earlier. The spat fall period started at 15 °C, with maximum numbers at 20-24 °C, and ended when the water temperature dropped below 5 °C. Redundancy analysis (RDA) demonstrated a strong relationship between larval and spat densities and water temperature.

  17. Short-Term and Long-Term Biological Effects of Chronic Chemical Contamination on Natural Populations of a Marine Bivalve.

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    Marine Breitwieser

    Full Text Available Understanding the effects of chronic chemical contamination on natural populations of marine organisms is complex due to the combined effects of different types of pollutants and environmental parameters that can modulate the physiological responses to stress. Here, we present the effects of a chronic contamination in a marine bivalve by combining multiple approaches that provide information on individual and population health. We sampled variegated scallops (Mimachlamys varia at sites characterized by different contaminants and contamination levels to study the short and long-term (intergenerational responses of this species to physiological stress. We used biomarkers (SOD, MDA, GST, laccase, citrate synthase and phosphatases as indicators of oxidative stress, immune system alteration, mitochondrial respiration and general metabolism, and measured population genetic diversity at each site. In parallel, concentration of 14 trace metals and 45 organic contaminants (PAHs, PCBs, pesticides in tissues were measured. Scallops were collected outside and during their reproductive season to investigate temporal variability in contaminant and biomarker levels. Our analyses revealed that the levels of two biomarkers (Laccase-type phenoloxidase and malondialdehyde were significantly correlated with Cd concentration. Additionally, we observed significant seasonal differences for four of the five biomarkers, which is likely due to the scallop reproductive status at time of sampling. As a source of concern, a location that was identified as a reference site on the basis of inorganic contaminant levels presented the same level of some persistent organic pollutants (DDT and its metabolites than more impacted sites. Finally, potential long-term effects of heavy metal contamination were observed for variegated scallops as genetic diversity was depressed in the most polluted sites.

  18. Genetic inviability is a major driver of type III survivorship in experimental families of a highly fecund marine bivalve.

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    Plough, L V; Shin, G; Hedgecock, D

    2016-02-01

    The offspring of most highly fecund marine fish and shellfish suffer substantial mortality early in the life cycle, complicating prediction of recruitment and fisheries management. Early mortality has long been attributed to environmental factors and almost never to genetic sources. Previous work on a variety of marine bivalve species uncovered substantial genetic inviability among the offspring of inbred crosses, suggesting a large load of early-acting deleterious recessive mutations. However, genetic inviability of randomly bred offspring has not been addressed. Here, genome-wide surveys reveal widespread, genotype-dependent mortality in randomly bred, full-sib progenies of wild-caught Pacific oysters (Crassostrea gigas). Using gene-mapping methods, we infer that 11-19 detrimental alleles per family render 97.9-99.8% of progeny inviable. The variable genomic positions of viability loci among families imply a surprisingly large load of partially dominant or additive detrimental mutations in wild adult oysters. Although caution is required in interpreting the relevance of experimental results for natural field environments, we argue that the observed genetic inviability corresponds with type III survivorship, which is characteristic of both hatchery and field environments and that our results, therefore, suggest the need for additional experiments under the near-natural conditions of mesocosms. We explore the population genetic implications of our results, calculating a detrimental mutation rate that is comparable to that estimated for conifers and other highly fecund perennial plants. Genetic inviability ought to be considered as a potential major source of low and variable recruitment in highly fecund marine animals.

  19. Evidence for immunomodulation and apoptotic processes induced by cationic polystyrene nanoparticles in the hemocytes of the marine bivalve Mytilus.

    Science.gov (United States)

    Canesi, L; Ciacci, C; Bergami, E; Monopoli, M P; Dawson, K A; Papa, S; Canonico, B; Corsi, I

    2015-10-01

    Polymeric nanoparticles can reach the marine environment from different sources as weathering of plastic debris and nanowaste. Nevertheless, few data are available on their fate and impact on marine biota. Polystyrene nanoparticles (PS NPs) can be considered as a model for studying the effects of nanoplastics in marine organisms: recent data on amino-modified PS NPs (PS-NH2) toxicity in sea urchin embryos underlined that marine invertebrates can be biological targets of nanoplastics. Cationic PS NPs have been shown to be toxic to mammalian cells, where they can induce apoptotic processes; however, no information is available on their effects and mechanisms of action in the cells of marine organisms. In this work, the effects of 50 nm PS-NH2 were investigated in the hemocytes of the marine bivalve Mytilus galloprovincialis. Hemocytes were exposed to different concentrations (1, 5, 50 μg/ml) of PS-NH2 suspension in ASW. Clear signs of cytoxicity were evident only at the highest concentrations (50 μg/ml). On the other hand, a dose dependent decrease in phagocytic activity and increase in lysozyme activity were observed. PS-NH2 NPs also stimulated increase in extracellular ROS (reactive oxygen species) and NO (nitric oxide) production, with maximal effects at lower concentrations. Moreover, at the highest concentration tested, PS-NH2 NPs induced apoptotic process, as evaluated by Flow cytometry (Annexin V binding and mitochondrial parameters). The results demonstrate that in marine invertebrates the immune function can represent a significant target for PS-NPs. Moreover, in Mytilus hemocytes, PS-NH2 NPs can act through mechanisms similar to those observed in mammalian cells. Further research is necessary on specific mechanisms of toxicity and cellular uptake of nanoplastics in order to assess their impact on marine biota.

  20. The complete genome of Teredinibacter turnerae T7901: an intracellular endosymbiont of marine wood-boring bivalves (shipworms.

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    Joyce C Yang

    Full Text Available Here we report the complete genome sequence of Teredinibacter turnerae T7901. T. turnerae is a marine gamma proteobacterium that occurs as an intracellular endosymbiont in the gills of wood-boring marine bivalves of the family Teredinidae (shipworms. This species is the sole cultivated member of an endosymbiotic consortium thought to provide the host with enzymes, including cellulases and nitrogenase, critical for digestion of wood and supplementation of the host's nitrogen-deficient diet. T. turnerae is closely related to the free-living marine polysaccharide degrading bacterium Saccharophagus degradans str. 2-40 and to as yet uncultivated endosymbionts with which it coexists in shipworm cells. Like S. degradans, the T. turnerae genome encodes a large number of enzymes predicted to be involved in complex polysaccharide degradation (>100. However, unlike S. degradans, which degrades a broad spectrum (>10 classes of complex plant, fungal and algal polysaccharides, T. turnerae primarily encodes enzymes associated with deconstruction of terrestrial woody plant material. Also unlike S. degradans and many other eubacteria, T. turnerae dedicates a large proportion of its genome to genes predicted to function in secondary metabolism. Despite its intracellular niche, the T. turnerae genome lacks many features associated with obligate intracellular existence (e.g. reduced genome size, reduced %G+C, loss of genes of core metabolism and displays evidence of adaptations common to free-living bacteria (e.g. defense against bacteriophage infection. These results suggest that T. turnerae is likely a facultative intracellular ensosymbiont whose niche presently includes, or recently included, free-living existence. As such, the T. turnerae genome provides insights into the range of genomic adaptations associated with intracellular endosymbiosis as well as enzymatic mechanisms relevant to the recycling of plant materials in marine environments and the production

  1. Measurements of the genotoxic potential of (xeno-)oestrogens in the bivalve mollusc Scrobicularia plana, using the Comet assay.

    Science.gov (United States)

    Petridis, Panos; Jha, Awadhesh N; Langston, William J

    2009-08-13

    There is increasing concern about the fate and effects of (geno)toxic and endocrine disrupting chemicals in sediments, highlighting the need to develop suitable monitoring tools. The deposit-feeding bivalve mollusc Scrobicularia plana has been put forward as a promising bioindicator of sediment contamination in estuaries. The recent demonstration of intersex in S. plana populations has been attributed to the feminisation of male clams following exposure to (xeno-)oestrogens, yet the mode of action of these endocrine disrupting chemicals (EDCs) remains largely unclear. One hypothesis that warrants further investigation is the possible involvement of genotoxicity. The first objective of this study was to assess whether the blood cells of S. plana are suitable for genotoxicity screening, using the alkaline single cell gel electrophoresis (Comet) assay. This was demonstrated successfully by exposing blood cells under in vitro conditions to a range of concentrations of the reference genotoxin hydrogen peroxide (H(2)O(2)): strong correlations between H(2)O(2) concentration and various comet parameters were found. Subsequently, the Comet assay was used to test whether the natural oestrogen 17beta-oestradiol (E2) and the synthetic (xeno)oestrogens ethinyloestradiol (EE2) and nonylphenol (NP) can produce genotoxic effects in S. plana, which might indicate possible involvement of mutagenicity in the mode of action of intersex development. In these short-term tests, clear genotoxic effects (significantly more DNA in the comet tail) were demonstrated by all EDCs, albeit only at high doses: 100 ng/L E2, 1 microg/L EE2 and 100 microg/L NP in vitro; and 1 microg/L E2 and 1mg/L NP after a 6-day in vivo exposure. Nevertheless, this study provides valuable preliminary data on the application and sensitivity of S. plana blood cells and suggests that the Comet assay is a useful tool, to screen for genotoxicity in in faunal clams and to examine further the links with higher order

  2. The bivalve Glycymeris planicostalis as a high-resolution paleoclimate archive for the Rupelian (Early Oligocene) of central Europe

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    Walliser, E. O.; Schöne, B. R.; Tütken, T.; Zirkel, J.; Grimm, K. I.; Pross, J.

    2015-04-01

    Current global warming is likely to result in a unipolar glaciated world with unpredictable repercussions on atmospheric and oceanic circulation patterns. These changes are expected to affect seasonal extremes and the year-to-year variability of seasonality. To better constrain the mode and tempo of the anticipated changes, climatologists require ultra-high-resolution proxy data of time intervals in the past, e.g., the Oligocene, during which boundary conditions were similar to those predicted for the near future. In the present paper, we assess whether such information can be obtained from shells of the long-lived bivalve mollusk Glycymeris planicostalis from the late Rupelian of the Mainz Basin, Germany. Our results indicate that the studied shells are pristinely preserved and provide an excellent archive for reconstructing changes of sea surface temperature on seasonal to interannual timescales. Shells of G. planicostalis grew uninterruptedly during winter and summer and therefore recorded the full seasonal temperature amplitude that prevailed in the Mainz Basin ~ 30 Ma. Absolute sea surface temperature data were reconstructed from δ18Oshell values assuming a δ18Owater signature that was extrapolated from coeval sirenian tooth enamel. Reconstructed values range between 12.3 and 22.0 °C and agree well with previous estimates based on planktonic foraminifera and shark teeth. However, temperatures during seasonal extremes vary greatly on interannual timescales. Mathematically re-sampled (i.e., corrected for uneven number of samples per annual increment) winter and summer temperatures averaged over 40 annual increments of three specimens equal 13.6 ± 0.8 and 17.3 ± 1.2 °C, respectively. Such high-resolution paleoclimate information can be highly relevant for numerical climate studies aiming to predict possible future climates in a unipolar glaciated or, ultimately, polar-ice-free world.

  3. The bivalve Glycymeris planicostalis as a high-resolution paleoclimate archive for Rupelian (Early Oligocene) of Central Europe

    Science.gov (United States)

    Walliser, E. O.; Schöne, B. R.; Tütken, T.; Zirkel, J.; Grimm, K. I.; Pross, J.

    2014-10-01

    Current global warming is likely to result in a unipolar glaciated world with unpredictable repercussions on atmospheric and oceanic circulation patterns. These changes are expected to affect seasonality as well as the frequency and intensity of decadal climate oscillations. To better constrain the mode and tempo of the anticipated changes, climatologists require high-resolution proxy data of time intervals in the past, e.g. the Early Oligocene during which boundary conditions were similar to those predicted for the near future. As demonstrated by the present study, pristinely preserved shells of the long-lived bivalve mollusk Glycymeris planicostalis from the late Rupelian of the Mainz Basin, Germany, provide an excellent archive to reconstruct changes of sea surface temperature on seasonal to inter-annual time scales. Their shells grew uninterruptedly during winter and summer and therefore recorded the full seasonal temperature amplitude that prevailed in the Mainz Basin 30 Ma ago. Absolute sea surface temperature data were faithfully reconstructed from δ18 Oshell values assuming a δ18Owater signature that was extrapolated from coeval sirenian tooth enamel. Extreme values ranged between 12.3 and 22.0°C and agree well with previous estimates based on planktonic foraminifera and shark teeth. However, summer and winter temperatures varied greatly on inter-annual time-scales. Winter and summer temperatures averaged over 40 annual increments of three specimens equaled 13.6 ± 0.8°C and 17.3 ± 1.2°C, respectively. Unless many samples are analyzed, this variability is hardly seen in foraminiferan tests. Our data also revealed decadal-scale oscillations of seasonal extremes which have - in the absence of appropriate climate archives - never been identified before for the Oligocene. This information can be highly relevant for numerical climate studies aiming to predict possible future climates in a unipolar glaciated or, ultimately, polar ice-free world.

  4. SNP detection from de novo transcriptome sequencing in the bivalve Macoma balthica: marker development for evolutionary studies.

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    Eric Pante

    Full Text Available Hybrid zones are noteworthy systems for the study of environmental adaptation to fast-changing environments, as they constitute reservoirs of polymorphism and are key to the maintenance of biodiversity. They can move in relation to climate fluctuations, as temperature can affect both selection and migration, or remain trapped by environmental and physical barriers. There is therefore a very strong incentive to study the dynamics of hybrid zones subjected to climate variations. The infaunal bivalve Macoma balthica emerges as a noteworthy model species, as divergent lineages hybridize, and its native NE Atlantic range is currently contracting to the North. To investigate the dynamics and functioning of hybrid zones in M. balthica, we developed new molecular markers by sequencing the collective transcriptome of 30 individuals. Ten individuals were pooled for each of the three populations sampled at the margins of two hybrid zones. A single 454 run generated 277 Mb from which 17K SNPs were detected. SNP density averaged 1 polymorphic site every 14 to 19 bases, for mitochondrial and nuclear loci, respectively. An [Formula: see text] scan detected high genetic divergence among several hundred SNPs, some of them involved in energetic metabolism, cellular respiration and physiological stress. The high population differentiation, recorded for nuclear-encoded ATP synthase and NADH dehydrogenase as well as most mitochondrial loci, suggests cytonuclear genetic incompatibilities. Results from this study will help pave the way to a high-resolution study of hybrid zone dynamics in M. balthica, and the relative importance of endogenous and exogenous barriers to gene flow in this system.

  5. Contrasting patterns of α- and β-diversity in deep-sea bivalves of the eastern and western North Atlantic

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    Brault, Solange; Stuart, Carol T.; Wagstaff, Martine C.; McClain, Craig R.; Allen, John A.; Rex, Michael A.

    2013-08-01

    We analyzed patterns of α- and β-diversity in deep-sea bivalves collected by epibenthic sleds from the western North Atlantic south of New England, and from the eastern North Atlantic in the Rockall Trough, Porcupine Seabight and Porcupine Abyssal Plain. In the western North Atlantic, species diversity, measured as the normalized expected number of species, shows a unimodal bathymetric trend peaking at mid-bathyal depths. In the eastern North Atlantic, diversity increases monotonically with depth reaching a maximum at abyssal depths. We used Baselga's (2010) metrics to distinguish two separate components of β-diversity along depth gradients, species dissimilarity among sites due to spatial replacement (turnover) and species loss leading to nestedness. We also examined the rank order of nestedness with depth using Rodríguez-Gironés and Santamaría's (2006) BINMATNEST. The primary difference in β-diversity between west and east centers on the composition of abyssal communities. In the western North Atlantic, abyssal assemblages are nested subsets of bathyal assemblages. In the eastern North Atlantic, turnover dominates at all depths. These very fundamental differences in community structure between the basins may be attributable to differences in food supply, which is greater in the eastern North Atlantic region sampled. POC-flux to abyssal depths in the east may not reach levels low enough to depress species diversity as it does in the west. In the west, the abyssal fauna is largely an impoverished nested subset of the bathyal fauna that shows less endemism and may be maintained partly by source-sink dynamics.

  6. First molecular phylogeny of the circumtropical bivalve family Pinnidae (Mollusca, Bivalvia): evidence for high levels of cryptic species diversity.

    Science.gov (United States)

    Lemer, Sarah; Buge, Barbara; Bemis, Amanda; Giribet, Gonzalo

    2014-06-01

    The family Pinnidae Leach, 1819, includes approximately 50 species of large subtidal and coastal marine bivalves. These commercially important species occur in tropical and temperate waters around the world and are most frequently found in seagrass meadows. The taxonomy of the family has been revised a number of times since the early 20th Century, the most recent revision recognizing 55 species distributed in three genera: Pinna, Atrina and Streptopinna, the latter being monotypic. However, to date no phylogenetic analysis of the family has been conducted using morphological or molecular data. The present study analyzed 306 pinnid specimens from around the world, comprising the three described genera and ca. 25 morphospecies. We sequenced the mitochondrial genes 16S rRNA and cytochrome c oxidase subunit I, and the nuclear ribosomal genes 18S rRNA and 28S rRNA. Phylogenetic analysis of the data revealed monophyly of the genus Atrina but also that the genus Streptopinna is nested within Pinna. Based on the strong support for this relationship we propose a new status for Streptopinna Martens, 1880 and treat it as a subgenus (status nov.) of Pinna Linnaeus, 1758. The phylogeny and the species delimitation analyses suggest the presence of cryptic species in many morphospecies displaying a wide Indo-Pacific distribution, including Pinna muricata, Atrina assimilis, A. exusta and P. (Streptopinna) saccata but also in the Atlantic species A. rigida. Altogether our results highlight the challenges associated with morphological identifications in Pinnidae due to the presence of both phenotypic plasticity and morphological stasis and reveal that many pinnid species are not as widely distributed as previously thought.

  7. Investigating the impact of drilling mud and its major components on bivalve species of Georges bank. Progress report No. 2, February 28, 1979-November 1, 1979

    Energy Technology Data Exchange (ETDEWEB)

    1979-11-01

    Results described in progress report No. 1 indicate that 0.3-1.0 grams of drilling mud/liter of seawater can stress bivalve molluscs and that metallic components of drilling muds are assimilated by these organisms. The results posed questions about the short- and long-term effects of stress on energy stores, reproduction, and metal assimilation; accordingly, this year's research program has focused on these three areas and on a continued chemical characterization of the drilling muds used.

  8. Changes in distribution patterns of 0-group bivalves in the Wadden Sea: Byssus-drifting releases juveniles from the constraints of hydrography

    Science.gov (United States)

    Armonies, W.

    1996-06-01

    The large-scale (km) distributional patterns of juvenile bivalves are established by larval settlement and subsequently changed due to actively initiated postlarval migrations (byssus-drifting), resuspension during sediment disturbance, and local differences in mortality. Repeated mapping of 0-group bivalve distribution during two summers was combined with simultaneous registrations of the numbers of drifting specimens. Species differed in their susceptibility to passive resuspension and their activity in byssus-drifting, but the two ways of entry into the water column were independent of each other. As a result, the relative magnitude of byssus-drifting and passive resuspension varied with the species. While hydrographical conditions always determined the changes in the distributional patterns of passively eroded species, this was not the case in active migrations of byssus-drifting bivalves. A comparison of the distributional patterns of juveniles over two consecutive years showed similar patterns in the tellinid clam Macoma balthica and the razor clam Ensis americanus. In these two species spatfall mainly occurred around mean low-tide level. Subsequently, juvenile M. balthica rapidly accumulated in the upper intertidal, whereas juvenile E. americanus accumulated subtidally. In mussels Mytilus edulis the distribution of juveniles only changed in a longshore direction, not in the tidal level occupied. The spatial pattern of cockles Cerastoderma edule changed from aggregation of the early spat in the mid and lower intertidal towards a more uniform distribution of recruits over these tidal flats. There were only a few patches of high abundance left at the end of summer. Finally, in juvenile clams Mya arenaria the spatial patterns of both spatfall and redistribution were unpredictable. On a km-scale, abundance of some species correlated with sediment granulometry. Presumably, this does not reflect a causal relationship but is a consequence of the correlation between

  9. DICKINSARTELLA FAUNA FROM THE SAIWAN FORMATION (OMAN: A BIVALVE FAUNA TESTIFYING TO THE LATE SAKMARIAN (EARLY PERMIAN CLIMATIC AMELIORATION ALONG THE NORTH-EASTERN GONDWANAN FRINGE.

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    CRISTIANO LARGHI

    2005-11-01

    Full Text Available The transitional faunas of the Permian Huqf succession of Oman make it one of the key-sections for the intercalibration of Early to Middle Permian biostratigraphical scales. The abundance of fossils improved the knowledge of some marine faunas which populated the North-Eastern Gondwanan fringe during times of climatic changes in the Permian. A Sterlitamakian (upper Sakmarian, Lower Permian bivalve fauna from the Saiwan Formation in the Huqf area, informally named "Dickinsartella Fauna", is described in the present paper. The specimens examined were collected from the "Pachycyrtella Bed" (Auctorum, the basal bed of the Formation in its type locality. The Dickinsartella Fauna can be identified for the presence of the new genus Dickinsartella, which dominates the bivalve thanatocoenosis with D. pistacina sp. n. (type species. The bivalve fauna from the Pachycyrtella Bed includes the new species Stutchburia sangallii and Promytilus  mazzolenii, and also Astartella obliqua Dickins, 1963, Nuculopsis cf. bangarraensis Dickins, 1963, ?Oriocrassatella sp., and indeterminable aviculopectinids. This fauna shows a low taxonomic diversity. Nevertheless, some species are represented by a high number of generally well-preserved specimens, i.e. some specimens of S. sangallii sp. n. and A. obliqua show part of the ligament.  The good preservation of the shells permitted the microstructural analysis of D. pistacina sp. n. and S. sangallii sp. n. The microstructure of S. sangallii sp. n. supports the close phylogenetical link between modiomorphids and crassatelloids recognized by some previous authors.The new genus Dickinsartella includes the more recent species belonging to the important Paleozoic Order Cyrtodontida Scarlato & Starobogatov, 1971. The discovery of Dickinsartella gen. n. and other taxa of the Pachycyrtella Bed, present also in the Sakmarian levels of the Carnarvon and Perth Basins in Western Australia,  indicates a wider distribution of the

  10. Toll signal transduction pathway in bivalves: complete cds of intermediate elements and related gene transcription levels in hemocytes of immune stimulated Mytilus galloprovincialis.

    Science.gov (United States)

    Toubiana, Mylène; Rosani, Umberto; Giambelluca, Sonia; Cammarata, Matteo; Gerdol, Marco; Pallavicini, Alberto; Venier, Paola; Roch, Philippe

    2014-08-01

    Based on protein domain structure and organization deduced from mRNA contigs, 15 transcripts of the Toll signaling pathway have been identified in the bivalve, Mytilus galloprovincialis. Identical searches performed on publicly available Mytilus edulis ESTs revealed 11 transcripts, whereas searches performed in genomic and new transcriptome sequences of the Pacific oyster, Crassostrea gigas, identified 21 Toll-related transcripts. The remarkable molecular diversity of TRAF and IKK coding sequences of C. gigas, suggests that the sequence data inferred from Mytilus cDNAs may not be exhaustive. Most of the Toll pathway genes were constitutively and ubiquitously expressed in M. galloprovincialis, although at different levels, and clearly induced after in vivo injection with bacteria. Such over-transcription was more rapid and intense with Gram-negative than with Gram-positive bacteria. Injection of a fungus modulated the transcription of few Toll pathway genes, with the induction levels of TLR/MyD88 complex being always less intense. Purified LPS and β-glucans had marginal effect whereas peptidoglycans were ineffective. At the moment, we found no evidence of an IMD transcript in bivalves. In conclusion, mussels possess a complete Toll pathway which can be triggered either by Gram-positive or Gram-negative bacteria.

  11. Effects of anthropogenic sound on digging behavior, metabolism, Ca2+/Mg2+ ATPase activity, and metabolism-related gene expression of the bivalve Sinonovacula constricta

    Science.gov (United States)

    Peng, Chao; Zhao, Xinguo; Liu, Saixi; Shi, Wei; Han, Yu; Guo, Cheng; Jiang, Jingang; Wan, Haibo; Shen, Tiedong; Liu, Guangxu

    2016-04-01

    Anthropogenic sound has increased significantly in the past decade. However, only a few studies to date have investigated its effects on marine bivalves, with little known about the underlying physiological and molecular mechanisms. In the present study, the effects of different types, frequencies, and intensities of anthropogenic sounds on the digging behavior of razor clams (Sinonovacula constricta) were investigated. The results showed that variations in sound intensity induced deeper digging. Furthermore, anthropogenic sound exposure led to an alteration in the O:N ratios and the expression of ten metabolism-related genes from the glycolysis, fatty acid biosynthesis, tryptophan metabolism, and Tricarboxylic Acid Cycle (TCA cycle) pathways. Expression of all genes under investigation was induced upon exposure to anthropogenic sound at ~80 dB re 1 μPa and repressed at ~100 dB re 1 μPa sound. In addition, the activity of Ca2+/Mg2+-ATPase in the feet tissues, which is directly related to muscular contraction and subsequently to digging behavior, was also found to be affected by anthropogenic sound intensity. The findings suggest that sound may be perceived by bivalves as changes in the water particle motion and lead to the subsequent reactions detected in razor clams.

  12. Evaluation of microwave and ultrasound extraction procedures for arsenic speciation in bivalve mollusks by liquid chromatography–inductively coupled plasma-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Clarissa M.M.; Nunes, Matheus A.G. [Departamento de Química, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil); Barbosa, Isa S.; Santos, Gabriel L. [Instituto de Química, Universidade Federal da Bahia, Salvador, BA (Brazil); Peso-Aguiar, Marlene C. [Instituto de Biologia, Universidade Federal da Bahia, Salvador, BA (Brazil); Korn, Maria G.A. [Instituto de Química, Universidade Federal da Bahia, Salvador, BA (Brazil); Flores, Erico M.M. [Departamento de Química, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil); Dressler, Valderi L., E-mail: vdressler@gmail.com [Departamento de Química, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil)

    2013-08-01

    Liquid chromatography–inductively coupled plasma-mass spectrometry (LC–ICP-MS) was used for arsenic speciation analysis in tissues of bivalve mollusks (Anomalocardia brasiliana sp. and Macoma constricta sp.). Microwave and ultrasound radiation, combined with different extraction conditions (solvent, sample amount, time, and temperature), were evaluated for As-species extraction from the mollusks' tissues. Accuracy, extraction efficiency, and the stability of As species were evaluated by analyzing certified reference materials (DORM-2, dogfish muscle; BCR-627, tuna fish tissue; and SRM 1566b, oyster tissue) and analyte recovery tests. The best conditions were found to be microwave-assisted extraction using 200 mg of samples and water at 80 °C for 6 min. The agreement of As-species concentration in samples ranged from 97% to 102%. Arsenobetaine (AsB) was the main species present in bivalve mollusk tissues, while monomethylarsonic acid (MMA) and arsenate (As(V)) were below the limit of quantification (0.001 and 0.003 μg g{sup −1}, respectively). Two unidentified As species also were detected and quantified. The sum of the As-species concentration was in agreement (90 to 104%), with the total As content determined by ICP-MS after sample digestion. - Highlights: • Method development for As speciation analysis by LC–ICP-MS • Evaluation of microwave and ultrasonic radiation for sample preparation • Investigation on As species content in mollusks.

  13. Characterization of pathogenic vibrios isolated from bivalve hatcheries in Galicia, NW Atlantic coast of Spain. Description of Vibrio tubiashii subsp. europaeus [corrected] subsp. nov.

    Science.gov (United States)

    Prado, Susana; Dubert, Javier; Barja, Juan L

    2015-02-01

    The taxonomic position of the bivalve pathogen PP-638 was studied together with five similar isolates. The strains were isolated from flat oyster (Ostrea edulis) and Manila clam (Venerupis philippinarum) cultures during outbreaks of disease in two shellfish hatcheries (Galicia, NW Spain). The pathogenicity, previously established for PP-638, was demonstrated with all isolates and for several bivalve species, including the original hosts. On the basis of phenotypic characterization and 16S rRNA gene sequences, a tight group was defined within the genus Vibrio. Multilocus sequence analysis (MLSA) based on concatenated sequences of the 16S rRNA gene and the five housekeeping genes recA, rpoA, pyrH, gyrB and ftsZ revealed that these strains form a cluster within the Orientalis clade, close to the species Vibrio tubiashii. The results of MLSA, the DDH rate and the phenotypic differences with the type strain of V. tubiashii supported the differentiation of the Galician isolates as a new subspecies within V. tubiashii, for which the name V. tubiashii subsp. europaeus [corrected] subsp. nov. is proposed (type strain PP-638(T)=CECT 8136(T)=DSM 7349(T)) The emended description of V. tubiashii is included. The pathogenicity assays widen the host range of V. tubiashii to add two unreported species, Venerupis decussata and Donax trunculus, and the described as relatively resistant species V. philippinarum.

  14. The Berriasian-Valanginian (Early Cretaceous) boundary transition at Santa Catarina Ticuá, Oaxaca state, southern Mexico: Ammonites, bivalves, calpionellids and their paleobiogeographic significance

    Science.gov (United States)

    Zell, Patrick; Stinnesbeck, Wolfgang; Beckmann, Seija; Adatte, Thierry; Hering, Fabio

    2015-10-01

    Ammonites, bivalves and calpionellids of the late Berriasian-early Valanginian from southern Mexico are poorly known; those here described are from the Sabinal Formation at Santa Catarina Ticuá, Oaxaca state. Samples were collected and analyzed bed-by-bed. Ammonite assemblages correlate to the West Mediterranean late Berriasian Subthurmannia boissieri and early Valanginian Thurmanniceras pertransiens and Neocomites neocomiensiformis zones and contain taxa, which are majorly endemic, although a few European species are also identified. The bivalve Arctotis cretacea (Felix, 1891) is common in several horizons throughout the section. Calpionellids are present in the upper part of the Santa Catarina Ticuá section and are indicative of the middle Berriasian Remaniella cadischiana Subzone, the late Berriasian Calpionellopsis Zone (including the Calpionellopsis simplex and Cs. oblonga subzones) and the early Valanginian Calpionellites darderi Subzone. Our data indicate that biogeographic correlation of faunal and environmental changes is possible across the Berriasian-Valanginian boundary between southern Mexico and faunal realms of the southwestern Gulf of Mexico and the western Tethys, and thus throughout the western hemisphere.

  15. Interactions of cationic polystyrene nanoparticles with marine bivalve hemocytes in a physiological environment: Role of soluble hemolymph proteins.

    Science.gov (United States)

    Canesi, Laura; Ciacci, Caterina; Fabbri, Rita; Balbi, Teresa; Salis, Annalisa; Damonte, Gianluca; Cortese, Katia; Caratto, Valentina; Monopoli, Marco P; Dawson, Kenneth; Bergami, Elisa; Corsi, Ilaria

    2016-10-01

    The bivalve Mytilus galloprovincialis has proven as a suitable model invertebrate for evaluating the potential impact of nanoparticles (NPs) in the marine environment. In particular, in mussels, the immune system represents a sensitive target for different types of NPs. In environmental conditions, both NP intrinsic properties and those of the receiving medium will affect particle behavior and consequent bioavailability/uptake/toxicity. However, the evaluation of the biological effects of NPs requires additional understanding of how, once within the organism, NPs interact at the molecular level with cells in a physiological environment. In mammalian systems, different NPs associate with serum soluble components, organized into a "protein corona", which affects particle interactions with target cells. However, no information is available so far on the interactions of NPs with biological fluids of aquatic organisms. In this work, the influence of hemolymph serum (HS) on the in vitro effects of amino modified polystyrene NPs (PS-NH2) on Mytilus hemocytes was investigated. Hemocytes were incubated with PS-NH2 suspensions in HS (1, 5 and 50µg/mL) and the results were compared with those obtained in ASW medium. Cell functional parameters (lysosomal membrane stability, oxyradical production, phagocytosis) were evaluated, and morphological changes were investigated by TEM. The activation state of the signalling components involved in Mytilus immune response (p38 MAPK and PKC) was determined. The results show that in the presence of HS, PS-NH2 increased cellular damage and ROS production with respect to ASW medium. The effects were apparently mediated by disregulation of p38 MAPK signalling. The formation of a PS-NH2-protein corona in HS was investigated by centrifugation, and 1D- gel electrophoresis and nano-HPLC-ESI-MS/MS. The results identified the Putative C1q domain containing protein (MgC1q6) as the only component of the PS-NH2 hard protein corona in Mytilus

  16. Matrix effects on a cell-based assay used for the detection of paralytic shellfish toxins in bivalve shellfish samples.

    Science.gov (United States)

    Aballay-Gonzalez, Ambbar; Ulloa, Viviana; Rivera, Alejandra; Hernández, Víctor; Silva, Macarena; Caprile, Teresa; Delgado-Rivera, Lorena; Astuya, Allisson

    2016-05-01

    Detecting marine biotoxins such as paralytic shellfish toxins (PSTs) is essential to ensuring the safety of seafood. The mouse bioassay is the internationally accepted method for monitoring PSTs, but technical and ethical issues have led to a search for new detection methods. The mouse neuroblastoma cell-based assay (Neuro-2a CBA) using ouabain and veratridine (O/V) has proven useful for the detection of PSTs. However, CBAs are sensitive to shellfish-associated matrix interferences. As the extraction method highly influences matrix interferences, this study compared three extraction protocols: Association of Official Analytical Chemists (AOAC) 2005.06, AOAC 2011.02 and an alternative liquid-liquid method. These methods were used to assess the matrix effect of extracts from four commercially important bivalve species (Chilean mussel, Magellan mussel, clam and Pacific oyster) in Neuro-2a CBA. Extracts from all three protocols caused a toxic effect in Neuro-2a cells (without O/V) when tested at a concentration of 25 mg of tissue-equivalent (TE) ml(-1). The greatest toxicity was obtained through the AOAC 2011.02 protocol, especially for the Chilean mussel and Pacific oyster extracts. Similar toxicity levels (less than 15%) were observed in all extracts at 3.1 mg TE ml(-1). When assessed in Neuro-2a CBA, AOAC 2005.06 extracts presented the lowest matrix interferences, while the highest interferences were observed for AOAC 2011.02 in Magellan mussel and clam extracts. Finally, the AOAC 2005.06 and alternative protocols were compared using Chilean mussel samples fortified with 40 and 80 µg STX per 100 g meat. The AOAC 2005.06 method demonstrated better results. In conclusion, the AOAC 2005.06 extracts exhibited the fewest interferences in the Neuro-2a CBA. Therefore, this extraction method should be considered for the implementation of Neuro-2a CBA as a high-throughput screening methodology for PST detection.

  17. Insights into shell deposition in the Antarctic bivalve Laternula elliptica: gene discovery in the mantle transcriptome using 454 pyrosequencing

    Directory of Open Access Journals (Sweden)

    Power Deborah M

    2010-06-01

    Full Text Available Abstract Background The Antarctic clam, Laternula elliptica, is an infaunal stenothermal bivalve mollusc with a circumpolar distribution. It plays a significant role in bentho-pelagic coupling and hence has been proposed as a sentinel species for climate change monitoring. Previous studies have shown that this mollusc displays a high level of plasticity with regard to shell deposition and damage repair against a background of genetic homogeneity. The Southern Ocean has amongst the lowest present-day CaCO3 saturation rate of any ocean region, and is predicted to be among the first to become undersaturated under current ocean acidification scenarios. Hence, this species presents as an ideal candidate for studies into the processes of calcium regulation and shell deposition in our changing ocean environments. Results 454 sequencing of L. elliptica mantle tissue generated 18,290 contigs with an average size of 535 bp (ranging between 142 bp-5.591 kb. BLAST sequence similarity searching assigned putative function to 17% of the data set, with a significant proportion of these transcripts being involved in binding and potentially of a secretory nature, as defined by GO molecular function and biological process classifications. These results indicated that the mantle is a transcriptionally active tissue which is actively proliferating. All transcripts were screened against an in-house database of genes shown to be involved in extracellular matrix formation and calcium homeostasis in metazoans. Putative identifications were made for a number of classical shell deposition genes, such as tyrosinase, carbonic anhydrase and metalloprotease 1, along with novel members of the family 2 G-Protein Coupled Receptors (GPCRs. A membrane transport protein (SEC61 was also characterised and this demonstrated the utility of the clam sequence data as a resource for examining cold adapted amino acid substitutions. The sequence data contained 46,235 microsatellites and 13

  18. Source and impact of lead contamination on {delta}-aminolevulinic acid dehydratase activity in several marine bivalve species along the Gulf of Cadiz

    Energy Technology Data Exchange (ETDEWEB)

    Company, R.; Serafim, A.; Lopes, B.; Cravo, A. [CIMA, University of Algarve, Campus de Gambelas, 8005-139 Faro (Portugal); Kalman, J.; Riba, I.; DelValls, T.A. [Catedra UNESCO/UNITWIN/WiCop, Department of Physical-Chemistry, Faculty Marine and Environmental Sciences, University of Cadiz, 11510 Puerto Real, Cadiz (Spain); Blasco, J. [Instituto Ciencias Marinas Andalucia (CSIC), Campus Rio San Pedro, 11510 Puerto Real, Cadiz (Spain); Delgado, J. [Department of Geology, University of Huelva, Avda Fuerzas Armadas s/n, 21071 Huelva (Spain); Sarmiento, A.M. [Catedra UNESCO/UNITWIN/WiCop, Department of Physical-Chemistry, Faculty Marine and Environmental Sciences, University of Cadiz, 11510 Puerto Real, Cadiz (Spain); Department of Geology, University of Huelva, Avda Fuerzas Armadas s/n, 21071 Huelva (Spain); Nieto, J.M. [Department of Geology, University of Huelva, Avda Fuerzas Armadas s/n, 21071 Huelva (Spain); Shepherd, T.J.; Nowell, G. [Department of Earth Sciences, University of Durham, Science Laboratories, Durham DH1 3LE (United Kingdom); Bebianno, M.J., E-mail: mbebian@ualg.pt [CIMA, University of Algarve, Campus de Gambelas, 8005-139 Faro (Portugal)

    2011-01-17

    Coastal areas and estuaries are particularly sensitive to metal contamination from anthropogenic sources and in the last few decades the study of space-time distribution and variation of metals has been extensively researched. The Gulf of Cadiz is no exception, with several rivers draining one of the largest concentrations of sulphide deposits in the world, the Iberian Pyrite Belt (IPB). Of these rivers, the Guadiana, one of the most important in the Iberian Peninsula, together with smaller rivers like the Tinto and Odiel, delivers a very high metal load to the adjacent coastal areas. The purpose of this work was to study the source and impact of lead (Pb) drained from historical or active mining areas in the IPB on the activity of a Pb inhibited enzyme ({delta}-aminolevulinic acid dehydratase, ALAD) in several bivalve species along the Gulf of Cadiz. Seven marine species (Chamelea gallina, Mactra corallina, Donax trunculus, Cerastoderma edule, Mytilus galloprovincialis, Scrobicularia plana and Crassostrea angulata) were collected at 12 sites from Mazagon, near the mouth of the rivers Tinto and Odiel (Spain), to Cacela Velha (Ria Formosa lagoon system, Portugal). Lead concentrations, ALAD activity and lead isotope ratios ({sup 206}Pb/{sup 204}Pb, {sup 207}Pb/{sup 204}Pb and {sup 208}Pb/{sup 204}Pb) were determined in the whole soft tissues. The highest Pb concentrations were determined in S. plana (3.50 {+-} 1.09 {mu}g g{sup -1} Pb d.w.) and D. trunculus (1.95 {+-} 0.10 {mu}g g{sup -1} Pb d.w.), while M. galloprovincialis and C. angulata showed the lowest Pb levels (<0.38 {mu}g g{sup -1} Pb d.w.). In general, ALAD activity is negatively correlated with total Pb concentration. However this relationship is species dependent (e.g. linear for C. gallina ALAD = -0.36[Pb] + 0.79; r = 0.837; or exponential for M. galloprovincialis ALAD = 2.48e{sup -8.3[Pb]}; r = 0.911). This indicates that ALAD activity has considerable potential as a biomarker of Pb and moreover, in

  19. Description of the Bivalve Littigiella pacifica n. sp. (Heterodonta: Galeommatoidea: Lasaeidae), Commensal with the Sipunculan Sipunculus nudus from the Ryukyu Islands, Japan

    DEFF Research Database (Denmark)

    Lützen, Jørgen; Kosuge, Takeharu

    2006-01-01

    In the Ryukyu Islands, Japan, Litigiella pacifica n. sp. lives attached to the body of the burrowing sipunculan Sipunculus nudus. The morphology of the shell and the soft parts are described and compared with other bivalve commensal with the same sipunculan. The new species is hermaphroditic, and...

  20. A new Permian bivalve-dominated assemblage in the Rio do Rasto Formation, Paraná Basin, Brazil: Faunal turnover driven by regional-scale environmental changes in a vast epeiric sea

    Science.gov (United States)

    Simões, Marcello Guimarães; Matos, Suzana Aparecida; Anelli, Luiz Eduardo; Rohn, Rosemarie; Warren, Lucas Veríssimo; David, Juliana Machado

    2015-12-01

    The basal portion of the Permian Rio do Rasto Formation (Serrinha Member), Passa Dois Group, Paraná Basin, Brazil, records an entirely new bivalve fauna intercalated between the underlying Pinzonella neotropica assemblage (uppermost portion of the Teresina Formation) and the overlying Leinzia similis assemblage (Rio do Rasto Formation). Mollusks of these assemblages lived in marginal shallow-water habitats of an immense epeiric sea and were dominated by endemic bivalve species. Taxonomic analysis revealed the presence of Terraia curvata (60.61%), Astartellopsis prosoclina (19.70%), Cowperesia emerita (10.61%), Leinzia curta (4.55%), Terraia bipleura (3.03%) and Beurlenella elongatella (1.52%), which are associated with conchostracans and plant remains. Species composition, abundance, and dominance in this novel assemblage differ notably from the preceding ones, suggesting a substantial evolutionary turnover. Regional-scale environmental changes recognized based on taphonomy, facies analysis, and geochemical data consist of progressive freshening of the marginal habitats of the Paraná Basin and taxic changes that include the following: (a) loss of genera, (b) decrease in bivalve abundance and ecological guilds, (c) disappearance of the dominant bivalve group (Pinzonellinae) and (d) diversification of Terrainae bivalves. The ecological signature also changed notably because only infaunal suspension-feeding bivalves are present, indicating a significant loss of functional diversity at the regional scale. Likely stressor factors (among others) are tied to freshening events, suggesting profound changes in (a) salinity, (b) primary productivity and (c) a lack of coarse, stable substrates coupled with high bioturbation rates. Hence, our regional example could offer valuable clues to benthic (bivalve) community responses in a habitat subjected to (a) rapid climate changes and (b) freshening events in shallow-water settings. Finally, the stratigraphic range of the

  1. Spatial and temporal distribution of tributyltin (TBT) in seawater, sediments and bivalves from coastal areas of Korea during 2001-2005.

    Science.gov (United States)

    Choi, Minkyu; Choi, Hee-Gu; Moon, Hyo-Bang; Kim, Gui-Young

    2009-04-01

    Tributyltin (TBT) concentrations were determined in seawater, sediments and bivalve samples collected from Korean coastal areas during 2001-2005, to investigate the levels and temporal variation in TBT contamination in relation to the timing of the imposition of regulations on TBT use in Korea. TBT concentrations ranged from TBT were found at locations close to intensive shipping traffic and industrial complexes, and the contamination at some hot spot areas was high enough to cause harmful effects on marine organisms. TBT concentrations and their occurrence in Korean coastal waters have been decreasing annually. In particular, TBT concentrations in seawater have dramatically decreased. This result is consistent with regulations and bans on the use of TBT in Korea.

  2. SURVEY ON V. CHOLERAE, V. VULNIFICUS AND V. PARAHAEMOLYTICUS IN BIVALVE MOLLUSCS OF THE ADRIATIC SEA AND PROPOSAL OF AN ANALYTICAL PROTOCOL

    Directory of Open Access Journals (Sweden)

    M.L. Valeri

    2009-06-01

    Full Text Available Bivalve molluscs from Adriatic sea were analyzed for V. parahaemolyticus, V. cholerae e V. vulnificus presence. The isolates on TCBS Agar and m-CPC Agar were selected on the basis of a new biochemical screening, that showed a good performance, because among 2344 strains from primary culture only 237 (10% were presumptively assigned to the species of interest. The PCR analyses was performed for the target genes toxR hlyA, ctxA, tcpI (V. cholerae, toxR, tl, tdh, trh (V. parahaemolyticus, vvhA and viuB (V. vulnificus. Among the 9 strains confirmed to belong to V. parahaemolyticus specie, 6 were sucrose positive. On 215 samples of molluscs only 5 resulted positive for V. parahaemolyticus being toxR+, tl+, although non pathogenic (tdh-, trh-, and none for V. cholerae e V. vulnificus.

  3. Cloning and characterization of cDNA probes for the analysis of metallothionein gene expression in the Mediterranean bivalves: Ruditapes decussatus and Cerastoderma glaucum.

    Science.gov (United States)

    Ladhar-Chaabouni, Rim; Mokdad-Gargouri, Raja; Denis, Françoise; Hamza-Chaffai, Amel

    2009-05-01

    cDNA probes have been developed for subsequent use in monitoring the cadmium exposure of the clam Ruditapes decussatus and the cockle Cerastoderma glaucum using metallothionein (MT) gene expression in different tissues of these species. Two partial MT cDNAs were isolated from Ruditapes decussatus and Cerastoderma glaucum. The identification of the nucleotide sequences showed that the cDNAs consist of 480 bp coding 72 amino acid proteins containing 21 cysteine residues organized in Cys-X-Cys motifs as classically described for MTs. The induction of MT gene expression in CdCl(2) treated bivalves was confirmed by dot blot analysis and suggests a potential specific tissue expression rate.

  4. Comparison of visual observation and excavation to quantify density of the endangered bivalve Unio crassus in rivers of north-eastern France

    Directory of Open Access Journals (Sweden)

    Lamand F.

    2014-04-01

    Full Text Available In the context of a rapid decline in several protected unionid species, government agencies urgently require a reliable method to estimate population size for the most endangered species. We used a dataset collected from 16 river stations in north-eastern France to compare the efficiency of visual estimation (bathyscope and a manual excavation to estimate numbers of the endangered bivalve Unio crassus. Our investigations indicated that, whereas a visual approach was sufficient to detect unionid presence, only 10% of all individuals were registered compared with manual excavation at the same site. In order to obtain an accurate density estimate (especially as regards the juvenile population, sediment excavation is necessary, despite it being time consuming and damaging to the mussel’s habitat.

  5. Cephalic and Limb Anatomy of a New Isoxyid from the Burgess Shale and the Role of “Stem Bivalved Arthropods” in the Disparity of the Frontalmost Appendage

    Science.gov (United States)

    Aria, Cédric; Caron, Jean-Bernard

    2015-01-01

    We herein describe Surusicaris elegans gen. et sp. nov. (in Isoxyidae, amended), a middle (Series 3, Stage 5) Cambrian bivalved arthropod from the new Burgess Shale deposit of Marble Canyon (Kootenay National Park, British Columbia). Surusicaris exhibits 12 simple, partly undivided biramous trunk limbs with long tripartite caeca, which may illustrate a plesiomorphic “fused” condition of exopod and endopod. We construe also that the head is made of five somites (= four segments), including two eyes, one pair of anomalocaridid-like frontalmost appendages, and three pairs of poorly sclerotized uniramous limbs. This fossil may therefore be a candidate for illustrating the origin of the plesiomorphic head condition in euarthropods, and questions the significance of the “two-segmented head” in, e.g., fuxianhuiids. The frontalmost appendage in isoxyids is intriguingly disparate, bearing similarities with both dinocaridids and euarthropods. In order to evaluate the relative importance of bivalved arthropods, such as Surusicaris, in the hypothetical structuro-functional transition between the dinocaridid frontal appendage and the pre-oral—arguably deutocerebral—appendage of euarthropods, we chose a phenetic approach and computed morphospace occupancy for the frontalmost appendages of 36 stem and crown taxa. Results show different levels of evolutionary decoupling between frontalmost appendage disparity and body plans. Variance is greatest in dinocaridids and “stem bivalved” arthropods, but these groups do not occupy the morphospace homogeneously. Rather, the diversity of frontalmost appendages in “stem bivalved” arthropods, distinct in its absence of clear clustering, is found to link the morphologies of “short great appendages,” chelicerae and antennules. This find fits the hypothesis of an increase in disparity of the deutocerebral appendage prior to its diversification in euarthropods, and possibly corresponds to its original time of development

  6. Acute effects of non-weathered and weathered crude oil and dispersant associated with the Deepwater Horizon incident on the development of marine bivalve and echinoderm larvae.

    Science.gov (United States)

    Stefansson, Emily S; Langdon, Chris J; Pargee, Suzanne M; Blunt, Susanna M; Gage, Susan J; Stubblefield, William A

    2016-08-01

    Acute toxicity tests (48-96-h duration) were conducted with larvae of 2 echinoderm species (Strongylocentrotus purpuratus and Dendraster excentricus) and 4 bivalve mollusk species (Crassostrea virginica, Crassostrea gigas, Mytilus galloprovincialis, and Mercenaria mercenaria). Developing larvae were exposed to water-accommodated fractions (WAFs) and chemically enhanced water-accommodated fractions (CEWAFs) of fresh and weathered oils collected from the Gulf of Mexico during the Deepwater Horizon incident. The WAFs (oils alone), CEWAFs (oils plus Corexit 9500A dispersant), and WAFs of Corexit alone were prepared using low-energy mixing. The WAFs of weathered oils had no effect on survival and development of echinoderm and bivalve larvae, whereas WAFs of fresh oils showed adverse effects on larval development. Similar toxicities were observed for weathered oil CEWAFs and WAFs prepared with Corexit alone for oyster (C. gigas and C. virginica) larvae, which were the most sensitive of the tested invertebrate species to Corexit. Mean 10% effective concentration values for total polycyclic aromatic hydrocarbons and dipropylene glycol n-butyl ether (a marker for Corexit) in the present study were higher than all concentrations reported in nearshore field samples collected during and after the Deepwater Horizon incident. The results suggest that water-soluble fractions of weathered oils and Corexit dispersant associated with the Deepwater Horizon incident had limited, if any, acute impacts on nearshore larvae of eastern oysters and clams, as well as other organisms with similar sensitivities to those of test species in the present study; however, exposure to sediments and long-term effects were not evaluated. Environ Toxicol Chem 2016;35:2016-2028. © 2016 SETAC.

  7. Molecular cloning, characterization, and the response of Cu/Zn superoxide dismutase and catalase to PBDE-47 and -209 from the freshwater bivalve Anodonta woodiana.

    Science.gov (United States)

    Xia, Xichao; Huang, Chuanfeng; Zhang, Dongxian; Zhang, Yi; Xue, Shipeng; Wang, Xiying; Zhang, Qingyuan; Guo, Lianghong

    2016-04-01

    Polybrominated diphenyl ethers-47 (PBDE-47) and -209 are significant components of total PBDEs in water and can catalyze the production of reactive oxygen species (ROS) in the organisms. Anti-oxidant enzymes play an important role in scavenging the high level of ROS. In the current study, two full-length cDNAs of Cu/Zn superoxide dismutase (CuZnSODs) and catalase (CAT) were isolated from freshwater bivalve Anodonta woodiana by rapid amplification of cDNA ends approach and respectively named as AwSOD and AwCAT. The nucleotide sequence of AwSOD cDNA had an open reading frame (ORF) of 465 bp encoding a polypeptide of 155 amino acids in which signature 1 GKHGFHVHEFGDNT and signature 2 GNAGARSACGVI of SODs were observed. Deduced amino acid sequence of AwSOD showed a significant similarity with that of CuZnSODs. AwCAT had an ORF 1536 bp encoding a polypeptide of 512 amino acids which contains a conserved catalytic site motif, and a proximal heme-ligand signature motif of CATs. The time-course expressions of AwSOD and AwCAT in hepatopancreas were measured by quantitative real-time PCR. Expressions of AwSOD and AwCAT showed a significant up-regulation in groups at a low concentration treatment of PBDE-47, a biphasic pattern in groups with a high concentration treatment. Administration of PBDE-209 could result in an up-regulation of AwSOD and AwCAT expressions with time- and dose-dependent matter. These results indicate that up-regulations of AwSOD and AwCAT expression of hepatopancreas of freshwater bivalve A. woodiana contribute to eliminate oxidative stress derived from PBDE-47 and -209 treated.

  8. Interactive effects of n-TiO2 and 2,3,7,8-TCDD on the marine bivalve Mytilus galloprovincialis.

    Science.gov (United States)

    Canesi, Laura; Frenzilli, Giada; Balbi, Teresa; Bernardeschi, Margherita; Ciacci, Caterina; Corsolini, Simonetta; Della Torre, Camilla; Fabbri, Rita; Faleri, Claudia; Focardi, Silvano; Guidi, Patrizia; Kočan, Anton; Marcomini, Antonio; Mariottini, Michela; Nigro, Marco; Pozo-Gallardo, Karla; Rocco, Lucia; Scarcelli, Vittoria; Smerilli, Arianna; Corsi, Ilaria

    2014-08-01

    Despite the growing concern over the potential biological impact of nanoparticles (NPs) in the aquatic environment, little is known about their interactions with other pollutants. The bivalve Mytilus sp, largely utilized as a sentinel for marine contamination, has been shown to represent a significant target for different types of NP, including n-TiO2, one of the most widespread in use. In this work, the possible interactive effects of n-TiO2 and 2,3,7,8-TCDD, chosen as models of NP and organic contaminant, respectively, were investigated in Mytilus galloprovincialis. In vitro experiments with n-TiO2 and TCDD, alone and in combination, were carried out in different conditions (concentrations and times of exposure), depending on the target (hemocytes, gill cells and biopsies) and the endpoint measured. Mussels were also exposed in vivo to n-TiO2 (100 μg L(-1)) or to TCDD (0.25 μg L(-1)), alone and in combination, for 96 h. A wide range of biomarkers, from molecular to tissue level, were measured: lysosomal membrane stability and phagocytosis in hemocytes, ATP-binding cassette efflux transporters in gills (gene transcription and efflux activity), several biomarkers of genotoxicity in gill and digestive cells (DNA damage, random amplified polymorphic DNA-RAPD changes), lysosomal biomarkers and transcription of selected genes in the digestive gland. The results demonstrate that n-TiO2 and TCDD can exert synergistic or antagonistic effects, depending on experimental condition, cell/tissue and type of measured response. Some of these interactions may result from a significant increase in TCDD accumulation in whole mussel organisms in the presence of n-TiO2, indicating a Trojan horse effect. The results represent the most extensive data obtained so far on the sub-lethal effects of NPs and organic contaminants in aquatic organisms. Moreover, these data extend the knowledge on the molecular and cellular targets of NPs in bivalves.

  9. Digestive selection underlies differential utilization of phytoplankton and sedimentary organics by infaunal bivalves: Experiments with cockles (Cerastoderma edule) using cross-labelled mixed diets.

    Science.gov (United States)

    Navarro, Enrique; Méndez, Soco; Urrutia, Miren Begoñe; Arambalza, Udane; Ibarrola, Irrintzi

    2016-09-01

    Differential utilization of phytoplankton and detrital particles present in natural sediments of mud-flats was studied in a series of experiments performed on the infaunal bivalve Cerastoderma edule. In order to assess digestive selection, parameters of food processing (organic ingestion rate: OIR, gross absorption efficiency: GAE and gut passage time: GPT) were recorded for each organic component in different combinations of food particles radio-labelled with (14)C. Experimental design included the use of both labelled diets of a sole organic component and cross-labelled diets; i.e., mixed suspensions presenting alternatively labelled one of the various components tested: phytoplankton cells, sedimentary organic particles and particulate detritus from vascular salt-marsh plants. Preferential absorption of phytoplankton was accounted for by absorption efficiency values that were two-fold those for sedimentary detritus when recorded with mixed diets of both organic components. Two factors contributed to this difference: a) higher digestibility of microalgae, measured as the ratio of GAE to GPT, and b) faster gut passage of detrital particles that results from digestive selection likely involving the preferential incorporation of phytoplankton into the digestive gland. However, when diets based on a sole organic component (either phytoplankton or detritus) were compared, larger GPT were recorded for detrital particles that enabled improving GAE of this rather refractory food. Overall results of these experiments are consistent with most studies in trophic ecology based on stable isotopes enrichment, concerning both the diversity of trophic sources used by marine bivalves and its preferential utilization of phytoplankton over phyto-detritus.

  10. Close evolutionary affinities between freshwater corbulid bivalves from the Neogene of western Amazonia and Paleogene of the northern Great Plains, USA

    Science.gov (United States)

    Anderson, Laurie C.; Hartman, Joseph H.; Wesselingh, Frank

    2006-03-01

    Freshwater corbulid bivalves found in Miocene deposits of western Amazonia have been considered products of an endemic radiation of a marine clade within the large lacustrine system occupying the region at that time. Our reexamination of Paleocene freshwater corbulids of the Tongue River Formation of western North Dakota and eastern Montana, however, extends the stratigraphic and geographic range of three Amazonian taxa— Pachydon, Ostomya, and Anticorbula—to the Paleocene of the northern Great Plains of the United States. Both Paleocene and Miocene freshwater corbulid taxa occur in large freshwater systems with an intermittent marine connection. To test the phylogenetic relationships of one particularly widespread Paleocene species ( Pachydon mactriformis), we conducted cladistic analyses using maximum parsimony and heuristic searches of matrices of conchologic characters. Seven species of Pachydon and Pebasia dispar from the western Amazonian Neogene, Pachydon mactriformis from the Paleocene of North Dakota, representative species of eight neotropical marine corbulid genera, and three additional corbulid taxa were included. Corbula was the outgroup. All analyses produced similar regions of stability within trees. One such area is a Pachydon crown group that includes P. mactriformis, indicating that Paleocene and Miocene Pachydon are not convergent. Our results also indicate that Pachydon does not represent a separate basal radiation within the family. However, we have not resolved a robust sister clade relationship for the Pachydon crown group. Two Amazonian Neogene taxa do not fall within the Pachydon crown group, and their phylogenetic position is not resolved. At this time, we do not have sufficient evidence to refine the definitions of Pachydon and Pachydontinae as monophyletic clades. Although we have evidence that three genera of corbulid bivalves ( Pachydon, Ostomya, and Anticorbula) in the Pebas Formation are not endemic and have long geologic

  11. Spatial and taxonomic variation in trace element bioaccumulation in two herbivores from a coal combustion waste contaminated stream.

    Science.gov (United States)

    Fletcher, Dean E; Lindell, Angela H; Stillings, Garrett K; Mills, Gary L; Blas, Susan A; Vaun McArthur, J

    2014-03-01

    Dissimilarities in habitat use, feeding habits, life histories, and physiology can result in syntopic aquatic taxa of similar trophic position bioaccumulating trace elements in vastly different patterns. We compared bioaccumulation in a clam, Corbicula fluminea and mayfly nymph Maccaffertium modestum from a coal combustion waste contaminated stream. Collection sites differed in distance to contaminant sources, incision, floodplain activity, and sources of flood event water and organic matter. Contaminants variably accumulated in both sediment and biofilm. Bioaccumulation differed between species and sites with C. fluminea accumulating higher concentrations of Hg, Cs, Sr, Se, As, Be, and Cu, but M. modestum higher Pb and V. Stable isotope analyses suggested both spatial and taxonomic differences in resource use with greater variability and overlap between species in the more physically disturbed site. The complex but essential interactions between organismal biology, divergence in resource use, and bioaccumulation as related to stream habitat requires further studies essential to understand impacts of metal pollution on stream systems.

  12. 微藻饵料对双壳贝类幼体生长影响的研究进展%Advance in the Effect of Microalgal Diets and Nutritional Value on the Growth of Early Life Stages of Bivalves

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    Microalgal diet is the key factor in shellfish growth and breeding. To gain a thorough knowledge of the effect of microalgal diets on the growth of early life stages of bivalves, this review summarizes the reports about this area since 1980 and analyzes the nutrition value of microalgae, including ingestibility, digestibility and biochemistry composition. It is concluded that different kinds of microalgal diets have different feeding effects, which is significant correlation with the fatty acid composition and sterols of microalgae, on bivalves and that the feeding effect of same microalgae vary among different life stages of bivalves. However the relevant mechanisms are still uncovered precisely. In terms of the nutritional value of microalgal diets, many studies on the n-3 polyunsaturated fatty acids have been done, however few researches on n-6 polyunsaturated fatty acids have been carried out till now. Besides, previous work conducted on bivalves has focused largely on larval and juvenile stages, with little attention given to postlarval stage. Therefore, it is necessary to continue these studies in future. Due to the complexity of relevant factors linked to bivalve growth, for future improvement, correlation analyses of the relationship between particular nutritional components and bivalve growth across a wide range of microalgal diets could provide a better understanding of nutritional value on the growth of early life stages of bivalves and further help to promote the development of the feeding biology of bivalves.%  饵料藻类影响着贝类的营养、生理与繁殖。为了深入了解微藻饵料对双壳贝类幼体生长的影响,归纳总结了1980年以来的相关研究报道,从微藻营养价值、贝类对微藻的摄食率、消化率及微藻饵料的生化组成等方面进行了分析。可以得出,不同的饵料藻类对贝类幼虫的饵料效果不同,同一种微藻的饵料效果在贝类发育的不同阶段也有差

  13. Biologie, abondance et cartographie de deux espèces de bivalves : l’huitre perlière et la coque glauque dans le golfe de Gabes

    OpenAIRE

    Derbali, Abdelkarim

    2011-01-01

    The pearl oyster Pinctada radiata and the cockle Cerastoderma glaucum are among the most abundant bivalve molluscs in southern Tunisian waters. These species are not currently subject to any investigation despite their important economic value in the world. For this reason, their biological parameters, their spatial distribution and their stock assessment were undertaken in the Gulf of Gabes. The reproductive cycle was studied in relation to variations of the environment parameters. The sp...

  14. The influence of small-scale circum-neutral pH change on Cu-bioavailability and toxicity to an estuarine bivalve (Austriella cf plicifera) in whole-sediment toxicity tests

    Energy Technology Data Exchange (ETDEWEB)

    Hutchins, Colin M. [Australian Rivers Institute, Griffith University, PMB 50, Gold Coast Mail Centre, Queensland 9726 (Australia)], E-mail: colin.hutchins@umontreal.ca; Teasdale, Peter R.; Yip Lee, Shing [Australian Rivers Institute, Griffith University, PMB 50, Gold Coast Mail Centre, Queensland 9726 (Australia); Simpson, Stuart L. [Centre for Environmental Contaminants Research, CSIRO Land and Water, Private Mailbag 7, Bangor, NSW 2234 (Australia)

    2008-11-01

    In whole-sediment toxicity tests employing metal-spiked sediment, pH is a crucial determinant of sediment geochemistry, sediment-porewater metal partitioning and metal bioavailability to benthic organisms. Small pH changes in metal-spiked sediment may therefore have important implications for toxicity to organisms. The present study evaluated the effect of small-scale pH changes (pH 6.6, 7.2, 7.6) in Cu-spiked sediment on metal bioavailability and subsequent organism response. Variation of pH produced distinct changes in sediment geochemistry. Increasing pH from 6.6 to 7.6 resulted in lower redox potential, greater acid volatile sulfide (AVS) formation, and lower partitioning of Cu, Fe and Mn to the porewater. The minor pH changes and associated variation in sediment geochemistry modified reburial rates and copper accumulation by the bivalve, Austriella cf plicifera. Bivalve reburial was slowest for the 1400 {mu}g g{sup -1} Cu-spiked pH 6.6 sediment, in which porewater copper concentrations exceeded 50 {mu}g L{sup -1}. Bivalve reburial was higher for pH 7.2 Cu-spiked sediments at all concentrations of copper investigated than in pH 6.6 and 7.6 sediments, where reburial rates were similar. Higher levels of bivalve activity suggest that A. cf plicifera may have an optimal pH range in the vicinity of pH 7.2. Tissue Cu concentrations varied with pH and appear dependent on spiked Cu concentration and organism activity. Strong linear correlations of tissue Cu concentration with all three Cu phases (overlying water, porewater and particulate phases), however, limited the ability to accurately determine the source of Cu uptake.

  15. Experimental growth pattern calibration of Antarctic bivalves shells to provide a biogenic archive of long-term high-resolution records of environmental and climatic change.

    Science.gov (United States)

    Lartaud, F.; Toulot, A.; Paulet, Y. M.

    2009-04-01

    Mollusc shells are used as an archive of climate variability in polar areas. The geochemistry (isotope and trace element) of the mineralized tissues is sensitive to the seawater physico-chemical changes (temperature, salinity, primary production …) and the accretionary growth of the shells provide intra-annual to centennial information. However, a serious age and growth profile calibration is necessary to establish a chronological time scale in the micro-sampling strategy. This kind of investigation on biogenic carbonates from Polar Regions suffers to the difficulties of a precise field-based standardization and validation. That's why ecology and shell growth history of many molluscs from those areas still remain unknown. In Boreal seas, bivalve metabolic activity is usually more reduced than in tropical or temperate domains, and the life span increase. For example, growth bands counting in the shells of the ocean Quahog (Arctica islandica) reveals that some of these shells are up to 250 years old (Wanamaker et al., 2008). Nevertheless in those environments, few species have highly defined growth increments calibration. The shell growth of the Antarctic scallop Adamussium colbecki is presently not well defined. Some authors attribute a growth rate close to the temperate equivalent species (Heilmayer et al., 2003) whereas others show a lower performance (Berkman et al., 2004). During the MACARBI program, to investigate the shell growth rate and determine a sclerochronologic profile, Adamussium colbecki and Laternula elliptica shells from Terre Adélie (Antarctic) were marked in situ with calcein during 6 hours and recapture a month later, in the austral summer 2007-2008. At the same time, a control of environmental conditions (temperature, salinity and chlorophyll) was carried out. All shells marked provide a distinct green fluorescent line, corresponding to the date of the marking. Calcein marking did not affect survivorship or growth of A. colbecki and L

  16. Interactive effects of CO₂ and trace metals on the proteasome activity and cellular stress response of marine bivalves Crassostrea virginica and Mercenaria mercenaria

    Energy Technology Data Exchange (ETDEWEB)

    Götze, Sandra [Alfred Wegener Institute, Helmholtz Centre for Polar, Marine Research, Functional Ecology, 27570 Bremerhaven (Germany); Department of Biology, University of North Carolina at Charlotte, Charlotte, NC 28223 (United States); Matoo, Omera B. [Department of Biology, University of North Carolina at Charlotte, Charlotte, NC 28223 (United States); Beniash, Elia [Department of Oral Biology, University of Pittsburgh, Pittsburgh, PA (United States); Saborowski, Reinhard [Alfred Wegener Institute, Helmholtz Centre for Polar, Marine Research, Functional Ecology, 27570 Bremerhaven (Germany); Sokolova, Inna M., E-mail: isokolov@uncc.edu [Department of Biology, University of North Carolina at Charlotte, Charlotte, NC 28223 (United States)

    2014-04-01

    Highlights: • Elevated PCO₂ enhanced accumulation of Cu and Cd in the gills of mollusks. • The proteasome activities were affected by metals but robust to elevated PCO₂. • Exposure to Cd and Cu had opposite effects on the proteasome activity. • Combined exposure to Cu and elevated PCO₂ negatively affected energy status. - Abstract: Increased anthropogenic emission of CO₂ changes the carbonate chemistry and decreases the pH of the ocean. This can affect the speciation and the bioavailability of metals in polluted habitats such as estuaries. However, the effects of acidification on metal accumulation and stress response in estuarine organisms including bivalves are poorly understood. We studied the interactive effects of CO₂ and two common metal pollutants, copper (Cu) and cadmium (Cd), on metal accumulation, intracellular ATP/ubiquitin-dependent protein degradation, stress response and energy metabolism in two common estuarine bivalves—Crassostrea virginica (eastern oyster) and Mercenaria mercenaria (hard shell clam). Bivalves were exposed for 4–5 weeks to clean seawater (control) and to either 50 μg L⁻¹ Cu or 50 μg L⁻¹ Cd at one of three partial pressures of CO₂ PCO₂ ~395, ~800 and ~1500 μatm) representative of the present-day conditions and projections of the Intergovernmental Panel for Climate Change (IPCC) for the years 2100 and 2250, respectively. Clams accumulated lower metal burdens than oysters, and elevated PCO₂ enhanced the Cd and Cu accumulation in mantle tissues in both species. Higher Cd and Cu burdens were associated with elevated mRNA expression of metal binding proteins metallothionein and ferritin. In the absence of added metals, proteasome activities of clams and oysters were robust to elevated PCO₂, but PCO₂ modulated the proteasome response to metals. Cd exposure stimulated the chymotrypsin-like activity of the oyster proteasome

  17. Determination of the variability of both hydrophilic and lipophilic toxins in endemic wild bivalves and carnivorous gastropods from the southern part of Chile.

    Science.gov (United States)

    Zamorano, Ruben; Marín, Michelle; Cabrera, Fabiola; Figueroa, Diego; Contreras, Cristóbal; Barriga, Andrés; Lagos, Néstor; García, Carlos

    2013-01-01

    The aim of this study was to analyse and determine the composition of paralytic shellfish poisoning (PSP) toxins and lipophilic toxins in the Region of Aysén, Chile, in wild endemic mussels (Mytilus chilensis, Venus antiqua, Aulacomya ater, Choromytilus chorus, Tagelus dombeii and Gari solida) and in two endemic carnivorous molluscs species (Concholepas concholepas and Argobuccinum ranelliforme). PSP-toxin contents were determined by using HPLC with fluorescence detection, while lipophilic toxins were determined by using LC-MS/MS. Mean concentrations for the total of PSP toxins were in the range 55-2505 μg saxitoxin-equivalent/100 g. The two most contaminated samples for PSP toxicity were bivalve Gari solida and carnivorous Argobuccinum ranelliforme with 2505 ± 101 and 1850 ± 137 μg saxitoxin-equivalent/100 g, respectively (p < 0.05). The lipophilic toxins identified were okadaic acid, dinophysistoxin-1 (DTX-1), azaspiracid-1 (AZA-1), pectenotoxin-2 (PTX-2) and yessotoxins (YTX). All analysed molluscs contained lipophilic toxins at levels ranging from 56 ± 4.8 to 156.1 ± 8.2 μg of okadaic acid-equivalent/kg shellfish together with YTX at levels ranging from 1.0 ± 0.1 to 18 ± 0.9 μg of YTX-equivalent/kg shellfish and AZA at levels ranging from 3.6 ± 0.2 to 31 ± 2.1 μg of AZA-equivalent/kg shellfish. Furthermore, different bivalves and gastropods differ in their capacity of retention of lipophilic toxins, as shown by the determination of their respective lipophilic toxins levels. In all the evaluated species, the presence of lipophilic toxins associated with biotransformation in molluscs and carnivorous gastropods was not identified, in contrast to the identification of PSP toxins, where the profiles identified in the different species are directly related to biotransformation processes. Thus, this study provides evidence that the concentration of toxins in the food intake of the evaluated species (Bivalvia and Gastropoda class) determines the degree of

  18. Spatial distribution of bivalve mollusc assemblages in the upwelling ecosystem of the continental shelf of Cabo Frio, Rio de Janeiro, Brazil Distribuição espacial das associações de moluscos bivalves na plataforma continental do ecossistema da ressurgência de Cabo Frio, Rio de Janeiro, Brasil

    Directory of Open Access Journals (Sweden)

    Abilio Soares-Gomes

    2005-03-01

    Full Text Available Bivalve mollusks of the continental shelf of Cabo Frio upwelling ecosystem were sampled monthly from February 1986 to February 1987 along a 30 to 60 m depth gradient. Mactra petiti Orbigny, 1846, and Tellina gibber Ihering, 1907 were constant species in 30 m; Nucula puelcha Orbigny, 1846, Adrana patagonica Orbigny, 1846, T. petitiana, T. gibber, and Corbula patagonica Orbigny, 1846 in 45 m; and N. puelcha, T. gibber, C. patagonica, and C. caribaea in 60 m. The number of rare species was similar along the depth gradient, ranging from six to ten species. The number of common species was higher in 60 m than in 30 m. Some species showed a continuous distribution but changed the frequency and abundance along the bathymetric gradient. The mean density was higher in 45-60 m than in 30 m, ranging from 15.6 ind.m-2, in 30 m, to 68.1 ind.m-2, in 60 m. There was no seasonal change in density nor in the taxocene structure during the studied period. On the other hand, the bivalve assemblage was spatially structured along the depth gradient, showing consistent changes from 30 to 60 m depths. Diversity and richness also follow this distribution pattern.Os moluscos bivalves da plataforma continental do ecossistema da ressurgência do Cabo Frio foram amostrados mensalmente de fevereiro de 1986 a fevereiro de 1987, entre 30 a 60 m de profundidade. Mactra petiti e Tellina gibber Ihering, 1907 foram espécies constantes a 30 m; Nucula puelcha Orbigny, 1846, Adrana patagonica Orbigny, 1846, T. petitiana, T. gibber e Corbula patagonica Orbigny, 1846 a 45 m; e N. puelcha, T. gibber, C. patagonica e C. caribaea a 60 m. O número de espécies raras foi similar nas diferentes profundidades, variando entre seis a dez espécies. O número de espécies comuns foi maior a 60 m que a 30 m. Algumas espécies apresentaram distribuição contínua porém, com variação na freqüência e abundância ao longo do gradiente batimétrico. A densidde média foi maior a 45-60 m do que

  19. Toxic effects of benzo[a]pyrene (Bap) and Aroclor1254 on embryogenesis, larval growth, survival and metamorphosis of the bivalve Meretrix meretrix.

    Science.gov (United States)

    Wang, Qing; Yang, Hongsheng; Liu, Baozhong; Wang, Xiaoyu

    2012-08-01

    To assess the potential toxicity of polycyclic aromatic hydrocarbons and polychlorinated biphenyls on the early development of Meretrix meretrix, the effects of benzo[a]pyrene (Bap) and Aroclor1254 on embryogenesis and larval development were investigated using static laboratory toxicity tests at nominal concentrations of 6.25-1,600 μg/L. Even at 1,600 μg/L, Bap and Aroclor1254 only caused minor reductions in embryo development rates. The 96 h LC(50) values for D-shaped larvae were 156 μg/L for Bap and 132 μg/L for Aroclor1254, respectively. The most sensitive toxicity endpoint in this study was metamorphosis, with an EC(50) value of 20 μg/L for Bap and 35 μg/L for Aroclor1254. Aroclor1254 was more toxic than Bap to embryos and larvae. Our results indicate that Bap and Aroclor1254 do not show extreme toxicity to M. meretrix embryos and larvae. These data provide information for evaluating the toxicity of Bap and Aroclor1254 on bivalve embryos, especially over the entire larval stages.

  20. 双壳类线粒体基因组结构分析%Analysis of Mitochondrial Genomic Structures in Bivalves

    Institute of Scientific and Technical Information of China (English)

    孟学平; 申欣; 赵娜娜; 田美; 郑立波; 程汉良; 阎斌伦; 董志国

    2013-01-01

    自GenBank检索到双壳类线粒体基因组,对其进行基因结构比较分析,以揭示线粒体基因组的演化规律,为线粒体基因组在物种演化和鉴定上的应用研究提供资料。结果共获得45个物种线粒体基因组序列,分布于双壳类5个目中。多数种类线粒体基因组大小为15~32 kb。平均 A+ T =62.9%。多数种类基因分布在重链上,而蚌目的基因分布在2条链上;少数种类(蚌目13个、帘蛤目的2个、贻贝目的1个、海螂目的1个,巨蛎属的贝类)的线粒体基因组含有13种蛋白质基因,其余种类为12种,缺少atp8;文蛤属4个种类、巨蛎属中4个种类、蚌目的11个种类、贻贝属中的紫贻贝和地中海贻贝的PCGs、rRNA基因排序在同属内或科内相同;珍珠贝目牡蛎科的10个种类线粒体基因组可分为7种类型;扇贝科海湾扇贝2个线粒体基因组基因结构相似外,其余种类无共享基因块;贻贝科的紫贻贝和海湾贻贝基因结构极相似。绿贻贝的结构独特,co x 2为双拷贝;海螂目的北方钻岩蛤基因结构与其它目的相似性极低。多数双壳类线粒体基因组非编码区占7.64%~40.26%,主非编码区大小为374~4341 nt。基于12种PCGs核苷酸/氨基酸的属内种间最小分歧度分别为0.2~1.0/0~1.0(文蛤属)、0.4~2.0/0~3.2(贻贝属)和1.9~13.9/0~6.4(巨蛎属)。%Bivalves mitochondrial genomes (mtDNA ) were retrieved from GenBank , and then the comparative analysis of the genomic structures were conducted to reveal the evolution of mitochondrial genomes in bivalves ,and the application of mitochondrial genome in the evolution and identification of related species. A total of 45 mtDNA sequences obtained ,ranging from 15 to 32 kb ,with average A+T content of 62. 9% ,were distributed in 5 orders in bivalves. Genes of most species were found to be distributed in the heavy

  1. Analysis of two-dimensional shapes by principal component score descriptors: geological interpretations from sand grains, pebbles, benthic foraminifera, and bivalve mollusks

    Energy Technology Data Exchange (ETDEWEB)

    Parks, J.M.

    1987-05-01

    Computerized quantitative shape analysis provides useful geological information not readily obtained in other ways. Principal Components Analysis (PCA) of properly rotated images reduces digitized outlines to a few shape descriptors. R-mode PC loadings, displayed graphically, exhibit the distinctive components of shape (elongation, triangularity, rectangularity, etc) in different orientations. Q-mode estimated PC scores are the shape descriptors for individual objects. Six shape descriptors are adequate to characterize typical geological outline shapes, such as silhouettes of sand grains, pebbles, and fossils. The original outlines are reconstructed using these shape descriptors as proportions for recombining the PC loadings. Proportions and rates of sand mixing from two sources are revealed by shape analysis of populations of sand grains from the Kansas and Missouri rivers sampled above and below their confluence. Unmixing (differential sorting during transport) is revealed by gradual shape changes in sands sampled along 330 mi of the Rio Grande (Del Rio, Texas, to the Gulf of Mexico). Pebbles from the Jackson Hole, Wyoming, area are readily identified as to fluvial or glacial origin by quantified shape. Outline shapes of benthic foraminifera from Maryland Miocene assemblages are classified by cluster and discriminant analyses of PC scores into 20 or more morphological types. Relative proportions of each morpho-type in stratigraphic samples are statistically correlated with independent paleoenvironmental indicators. Intra- and inter-specific changes in shapes of several genera of middle Miocene bivalves from Maryland show three distinct patterns through time: minor irregular changes (= stasis.); abrupt jumps (= punctuated equilibria.); and gradual trends (= gradualism.).

  2. Exon-primed, intron-crossing (EPIC) loci for five nuclear genes in deep-sea protobranch bivalves: primer design, PCR protocols and locus utility.

    Science.gov (United States)

    Jennings, Robert M; Etter, R J

    2011-11-01

    We describe PCR primers and amplification protocols developed to obtain introns from conserved nuclear genes in deep-sea protobranch bivalves. Because almost no sequence data for protobranchs are publically available, mollusk and other protostome sequences from GenBank were used to design degenerate primers, making these loci potentially useful in other invertebrate taxa. Amplification and sequencing success varied across the test group of 30 species, and we present five loci spanning this range of outcomes. Intron presence in the targeted regions also varied across genes and species, often within single genera; for instance, the calmodulin and β-tubulin loci contained introns with high frequency, whereas the triose phosphate isomerase locus never contained an intron. In introns for which we were able to obtain preliminary estimates of polymorphism levels in single species, polymorphism was greater than traditional mitochondrial loci. These markers will greatly increase the ability to assess population structure in the ecologically important protobranchs, and may prove useful in other taxa as well.

  3. BIVALVES AND BRACHIOPODS NEAR THE PERMIAN-TRIASSIC BOUNDARY FROM THE BÜKK MOUNTAINS (BÁLVÁNY-NORTH SECTION, NORTHERN HUNGARY

    Directory of Open Access Journals (Sweden)

    RENATO POSENATO

    2005-07-01

    Full Text Available In the Bükk Mountains the Upper Permian is represented by the Nagyvisnyó Limestone, which contains very rich marine assemblages. It is overlain by the Gerennavár Limestone (uppermost Permian-Lower Triassic which records the effects of the Permo-Triassic mass extinction with a dramatic decrease in diversity and abundance of fossils. The basal Gerennavár Limestone is represented by a clayey marl unit (basal beds deposited in a quiet, low-energy marine environment below the storm wave-base, whose maximum thickness, about one meter, is recorded in the Bálvány-North section. From this locality a relatively diversified and abundant marine benthonic assemblage has been collected, and is here described. Bivalves are represented by: Bakevellia cf. ceratophaga (Schlotheim, ? Pterinopectinidae gen. et sp. indet., Eumorphotis lorigae sp. n., the most abundant species, Entolium piriformis (Liu and Pernopecten latangulatus Yin. Brachiopods are less frequent, and the following four species have been identified: Spinomarginifera sp., Orthothetina ladina (Stache, Ombonia tirolensis (Stache and Orbicoelia tschernyschewi (Likharew. An exact age of this fauna, based on conodonts, is not yet available, but the strong affinities with those of the lower Tesero Member (Dolomites and the Lower Kathwai Member (Pakistan suggest a latest Permian age (? Hindeodus praeparvus Zone. If so, the Bálvány-North section becomes one of the few in the world which records the last bioevents of the Palaeozoic.

  4. Forming nacreous layer of the shells of the bivalves Atrina rigida and Pinctada margaritifera: an environmental- and cryo-scanning electron microscopy study.

    Science.gov (United States)

    Nudelman, Fabio; Shimoni, Eyal; Klein, Eugenia; Rousseau, Marthe; Bourrat, Xavier; Lopez, Evelyne; Addadi, Lia; Weiner, Steve

    2008-05-01

    A key to understanding control over mineral formation in mollusk shells is the microenvironment inside the pre-formed 3-dimensional organic matrix framework where mineral forms. Much of what is known about nacre formation is from observations of the mature tissue. Although these studies have elucidated several important aspects of this process, the structure of the organic matrix and the microenvironment where the crystal nucleates and grows are very difficult to infer from observations of the mature nacre. Here, we use environmental- and cryo-scanning electron microscopy to investigate the organic matrix structure at the onset of mineralization in the nacre of two mollusk species: the bivalves Atrina rigida and Pinctada margaritifera. These two techniques allow the visualization of hydrated biological materials coupled with the preservation of the organic matrix close to physiological conditions. We identified a hydrated gel-like protein phase filling the space between two interlamellar sheets prior to mineral formation. The results are consistent with this phase being the silk-like proteins, and show that mineral formation does not occur in an aqueous solution, but in a hydrated gel-like medium. As the tablets grow, the silk-fibroin is pushed aside and becomes sandwiched between the mineral and the chitin layer.

  5. Striated muscle twitchin of bivalves has "catchability", the ability to bind thick filaments tightly to thin filaments, representing the catch state.

    Science.gov (United States)

    Tsutsui, Yasutaka; Yoshio, Maki; Oiwa, Kazuhiro; Yamada, Akira

    2007-01-12

    Catch muscles are found in some invertebrates which can maintain high passive tension with little energy expenditure for long periods after their active contraction. Twitchin in the catch muscles has the ability to facilitate the tight binding of thick filaments to thin filaments, which is the structural basis of the catch tension. We defined this ability as catchability and assessed the catchability of twitchins purified from striated muscles of an oyster (Crassostrea gigas) and a scallop (Mimachlamys nobilis), by using an in vitro catch assay where the binding of filaments could be directly visualized under a light microscope. We found that both twitchins had catchability, even though these muscles are not considered to be catch muscles in physiological experiments. In addition, these muscles contained water-soluble factors regulating the binding of the catch, probably protein kinase A and protein phosphatase 2B. These findings suggest that not only bivalve smooth muscles but also striated muscles have a system that regulates their relaxation rate through the catchability of twitchin, at least at the molecular level.

  6. The bivalve Placuna (Indoplacuna) miocenica from the Middle Miocene of Siwa Oasis, Western Desert of Egypt: Systematic paleontology, paleoecology, and taphonomic implications

    Science.gov (United States)

    El-Sabbagh, Ahmed M.; El Hedeny, Magdy M.; Rashwan, Mohammed A.; Abdel Aal, Abdel Aal A.

    2016-04-01

    The present study investigated the epifaunal, free lying bivalve Placuna (Indoplacuna) miocenica (Fuchs, 1883) encountered in the Middle Miocene Marmarica Formation of Siwa Oasis, Western Desert, Egypt, in terms of systematic paleontology, paleoecology and taphonomy. Well to moderately preserved shells of this species were collected from three sections. They have been found embedded in sandy, marly and chalky limestones. Although they are extremely thin and fragile, they occurred as complete disarticulated and articulated valves. Specimens of P. (I.) miocenica are highly accumulated in the north Siwa section forming a coquinoid band (30 cm thick). In addition, they are generally distributed sporadically in different stratigraphic levels within the three studied sequences. Taphonomic observations indicated that these shells were affected by encrustation, bioerosion, disarticulation, fragmentation and abrasion. Moreover, valves of this species suffered minor chipping along their fragile margins. The occurrence of the studied species associated with oysters and other benthic faunal assemblages within carbonate sediments revealed shallow, low energy, warm and intertidal environments with periods of relatively agitated conditions.

  7. Differential adaptations between cold-stenothermal environments in the bivalve Lissarca cf. miliaris (Philobryidae) from the Scotia Sea islands and Antarctic Peninsula

    Science.gov (United States)

    Reed, Adam J.; Linse, Katrin; Thatje, Sven

    2014-04-01

    The cold stenothermal nature of the Southern Ocean, and highly adapted fauna living within, raises the question of how much intra-specific variation there is among invertebrate populations, and how variation may have a role in speciation processes through ecological divergence, natural selection, and reproductive isolation. Despite decades of collecting biological material, this question remains largely unanswered, and many studies compare ‘populations' of pooled material from wide geographic ranges to compensate for sampling constraints. In this study, variations in ecophysiological traits are explored by measuring growth, reproduction, and shell morphology among six populations of the small bivalve Lissarca cf. miliaris (Philippi, 1845) from the Southern Ocean, which experience subtle differences in temperature, disturbance, and food availability. There are significant differences in shell morphology and growth among different populations and slower growth rates at higher latitude populations. Prodissoconch sizes show an inverse ‘U' shaped relationship with latitude, and are correlated with egg size at South Georgia and King George Island's Potter Cove. Higher brood sizes at the South Georgia population represent a trade-off with lower egg size, and correlate with shell morphology by offering lower internal capacity to brood young. Lower investment into offspring and morphological variations in L. cf. miliaris highlight the importance of local scale environmental variations on species' ecology. These variations in physical traits appear to be underestimated in the Southern Ocean, but may be important drivers of ecological divergence and speciation, which should be considered in future genetic investigations on different invertebrate populations.

  8. Biodeposition of suspended particles in fresh seawater for industrial aquaculture by filter-feeding bivalves%贝类对海水养殖新源水悬浮物的生物沉积作用

    Institute of Scientific and Technical Information of China (English)

    张延青; 张少军; 周毅; 刘鹰; 徐洋

    2011-01-01

    It is so slow to remove these materials though gravity sedimentation; and other methods will consume large energy as general mechanical filter or foam separation. In this study, In order to remove the suspended particles in fresh seawater for industrial seawater aquaculture. We chose two kinds of filter-feeding bivalves, the Pacific oyster Crassostrea gigas and the blue mussel Mytilus galloprovincialis for biodeposition of suspended particles. The biological deposition rate(BDR) by spot experiments in different times was calculated, and the efficiency of removing the suspended particles in reservoir with fresh seawater by these two kinds of bivalves was assessed. The results showed that when the temperature of reservoir was at 17-25℃, bio-deposition rates of the two kinds of filter-feeding bivalves were 1.08-1.32 g/(ind-d) (Crassostrea gigas) and 0.65~0.85 g/(ind-d) (Mytilus galloprovincialis), respectively. Compared with no bivalves in reservoir, the bio-deposition rates with cultivation of a large number of bivalves in the reservoir was higher than no bivalves. The study shows that filter-feeding bivalve could remove suspended particles in fresh seawater and reduce the treatment load of fresh seawater.%为了去除工厂化海水养殖新源水中含有的大量悬浮颗粒物,针对蓄水池中悬浮物重力沉降速率较慢,利用一般的机械过滤或泡沫分离又消耗大量能源的缺点,该试验选择适应能力强的滤食性双壳贝类太平洋牡蛎(Crassostrea gigas)和紫贻贝(Mytilus galloprovincialis),在不同时期进行现场试验,测定其对蓄水池新源水中悬浮物的生物沉积速率并评估通过一定规模放养贝类对整个蓄水池中悬浮物的沉积效果.结果表明,在适宜的温度条件下( 17~25℃),太平洋牡蛎对蓄水池水中悬浮物生物沉积速率为1.08~1.32 g/(ind-d),紫贻贝为0.65~0.85 g/(ind-d).通过在蓄水池中大量吊笼养贝类,蓄水池中贝类养殖区的悬浮物沉降

  9. Spatial and temporal distribution of the zoobenthos community during the filling up period of Porto Primavera Reservoir (Paraná River, Brazil).

    Science.gov (United States)

    Jorcin, A; Nogueira, M G; Belmont, R

    2009-02-01

    This study is part of the limnological monitoring undertaken by the Energy Company of the State of São Paulo (CESP) during the filling up process of the Porto Primavera Reservoir (Hydroelectric Power Plant Engenheiro Sérgio Motta). This reservoir, located in the high Paraná River between the States of São Paulo and Mato Grosso do Sul, is the fourth largest in the country. The first filling up phase started in December 1998 and the second phase in March 2001. Samples for benthic community and sediment characteristics analysis were quarterly collected between August of 1999 and November 2001 and also in August of 2002 (11 sampling campaigns). Samplings were carried out at 13 stations distributed in the reservoir, and at one point located downstream of the dam. 128 invertebrate taxa were identified, being Mollusca, Annelida, Insecta and Nematoda the dominant groups during almost the whole study period. Insecta was the best represented class (9 different orders), and Diptera contributed with higher number of taxa, 63. The exotic species of bivalve Corbicula fluminea was recorded in all sampling stations showing its great capacity to colonize new habitats in the neotropical region. Noticeable variations in the fauna density were observed, considering both different periods and locations. The maximum density of organisms (mean value of 7812 ind.m-2) was recorded in the center of the reservoir, and the minimum (mean value 9 ind.m-2) in the more lacustrine area near the dam. The greatest species richness per sample (24 taxa) was observed in the reservoir upstream (fluvial zone). The maximum diversity (Shannon-Wiener Index) per station/period, 3.82 and 3.86 bits.ind-1, were calculated in the transitional river/reservoir zone during the beginning (August 1999) and in the reservoir central zones in the end (August 2002) of the filling up period, respectively. There was no clear relation between the distribution of the different faunistic groups and the sediment

  10. Spatial and temporal distribution of the zoobenthos community during the filling up period of Porto Primavera Reservoir (Paraná River, Brazil

    Directory of Open Access Journals (Sweden)

    A. Jorcin

    Full Text Available This study is part of the limnological monitoring undertaken by the Energy Company of the State of São Paulo (CESP during the filling up process of the Porto Primavera Reservoir (Hydroelectric Power Plant Engenheiro Sérgio Motta. This reservoir, located in the high Paraná River between the States of São Paulo and Mato Grosso do Sul, is the fourth largest in the country. The first filling up phase started in December 1998 and the second phase in March 2001. Samples for benthic community and sediment characteristics analysis were quarterly collected between August of 1999 and November 2001 and also in August of 2002 (11 sampling campaigns. Samplings were carried out at 13 stations distributed in the reservoir, and at one point located downstream of the dam. 128 invertebrate taxa were identified, being Mollusca, Annelida, Insecta and Nematoda the dominant groups during almost the whole study period. Insecta was the best represented class (9 different orders, and Diptera contributed with higher number of taxa, 63. The exotic species of bivalve Corbicula fluminea was recorded in all sampling stations showing its great capacity to colonize new habitats in the neotropical region. Noticeable variations in the fauna density were observed, considering both different periods and locations. The maximum density of organisms (mean value of 7812 ind.m-2 was recorded in the center of the reservoir, and the minimum (mean value 9 ind.m-2 in the more lacustrine area near the dam. The greatest species richness per sample (24 taxa was observed in the reservoir upstream (fluvial zone. The maximum diversity (Shannon-Wiener Index per station/period, 3.82 and 3.86 bits.ind-1, were calculated in the transitional river/reservoir zone during the beginning (August 1999 and in the reservoir central zones in the end (August 2002 of the filling up period, respectively. There was no clear relation between the distribution of the different faunistic groups and the sediment

  11. Lead and other heavy metals (cadmium and mercury accumulation in bivalve mollusks (Mytilus galloprovincialis, Ruditapes spp. and Crassostrea gigas sampled in Sardinia in 2008-2012

    Directory of Open Access Journals (Sweden)

    Pierluigi Piras

    2013-12-01

    Full Text Available The Sardinian shellfish farming, like the national, is mainly focused on mussels and carpet-shell clams, still less on cupped oyster farming. After Olbia’s Gulf, various lagoon areas along the coastal perimeter have been interested to shellfish farming. They are transitional waters, whose state of pollution must be evaluated both as ecosystem’s health and as directly/indirectly human risk. This also applies to heavy metals such as lead, cadmium and mercury, arising both from anthropogenic that geological-natural activity. The aim of the present study is to investigate the variability of the concentrations of these metals in different mollusks to make a comparative assessment, detect trends (over the five-years or cyclicrecurring and identify hot spots. In 2008- 2012, 984 samples have been analysed by inductively coupled plasma mass spectrometry technique. Of them, 599 in pre-marketing (for classification of production areas or their monitoring and the remaining during marketing. The difference between the average levels of the three metals in the different mollusks species was statistically significant, with Pb>Cd>Hg, and there was evidence of a gradual downward trend, albeit moderate, in the contamination levels, with a significant seasonality in concentrations levels, of lead in particular. Also comparisons between the bio-monitored coastal areas were statistically different. Since the samples were representative of the entire production of bivalve mollusks in Sardinia and the contamination allowable limits have never been exceeded in the products marketed, it can be concluded that these products are safe, pointing out that maintenance of monitoring/surveillance plans provides useful information species-dependent, site-specific and temporal trends.

  12. Matrix proteins in the shell of cultured pearl bivalves%养殖珍珠贝贝壳基质蛋白研究进展

    Institute of Scientific and Technical Information of China (English)

    刘晓军; 李家乐

    2013-01-01

    Matrix proteins exist in the biomineralization microstructure of shells and pearls. Calcium carbonate forms the high regular and complex biomineralization microstructure under the influence of matrix proteins. It is important to study the matrix proteins in the shells and pearls of the cultured pearl bivalves for the understanding of the mechanism of the pearl formation. This paper reviews the matrix proteins which had been found and studied, their structure and function in biomineralization, and current research progress of the understanding of the mechanism of the pearl formation with the knowledge of matrix proteins.%基质蛋白是一类存在于贝壳和珍珠矿化结构中的蛋白,在贝壳和珍珠的形成过程中,碳酸钙在基质蛋白的作用下形成高度复杂有序的生物矿化结构.因此在养殖珍珠贝中进行基质蛋白的研究对阐明珍珠的形成机理具有重要意义.概述了养殖珍珠贝中已发现的基质蛋白和它们的结构特点、矿化功能以及在珍珠形成过程中作用机理的最新研究进展,旨在为进一步提高珍珠质量提供参考资料.

  13. Molecular phylogenetics and systematics of the bivalve family Ostreidae based on rRNA sequence-structure models and multilocus species tree.

    Science.gov (United States)

    Salvi, Daniele; Macali, Armando; Mariottini, Paolo

    2014-01-01

    The bivalve family Ostreidae has a worldwide distribution and includes species of high economic importance. Phylogenetics and systematic of oysters based on morphology have proved difficult because of their high phenotypic plasticity. In this study we explore the phylogenetic information of the DNA sequence and secondary structure of the nuclear, fast-evolving, ITS2 rRNA and the mitochondrial 16S rRNA genes from the Ostreidae and we implemented a multi-locus framework based on four loci for oyster phylogenetics and systematics. Sequence-structure rRNA models aid sequence alignment and improved accuracy and nodal support of phylogenetic trees. In agreement with previous molecular studies, our phylogenetic results indicate that none of the currently recognized subfamilies, Crassostreinae, Ostreinae, and Lophinae, is monophyletic. Single gene trees based on Maximum likelihood (ML) and Bayesian (BA) methods and on sequence-structure ML were congruent with multilocus trees based on a concatenated (ML and BA) and coalescent based (BA) approaches and consistently supported three main clades: (i) Crassostrea, (ii) Saccostrea, and (iii) an Ostreinae-Lophinae lineage. Therefore, the subfamily Crassostreinae (including Crassostrea), Saccostreinae subfam. nov. (including Saccostrea and tentatively Striostrea) and Ostreinae (including Ostreinae and Lophinae taxa) are recognized [corrected]. Based on phylogenetic and biogeographical evidence the Asian species of Crassostrea from the Pacific Ocean are assigned to Magallana gen. nov., whereas an integrative taxonomic revision is required for the genera Ostrea and Dendostrea. This study pointed out the suitability of the ITS2 marker for DNA barcoding of oyster and the relevance of using sequence-structure rRNA models and features of the ITS2 folding in molecular phylogenetics and taxonomy. The multilocus approach allowed inferring a robust phylogeny of Ostreidae providing a broad molecular perspective on their systematics.

  14. Cholinesterase activity in the tissues of bivalves Noah's ark shell (Arca noae) and warty venus (Venus verrucosa): characterisation and in vitro sensitivity to organophosphorous pesticide trichlorfon.

    Science.gov (United States)

    Perić, Lorena; Ribarić, Luka; Nerlović, Vedrana

    2013-08-01

    Cholinesterase (ChE, EC 3.1.1.7) activity was investigated in gills and adductor muscle of two bivalve species: Arca noae and Venus verrucosa. The properties of ChEs were investigated using acetylcholine iodide (ASCh), butyrylcholine iodide (BSCh) and propionylcholine iodide (PrSCh) as substrates and eserine, BW254c51 and iso-OMPA as specific inhibitors. The highest level of ChE activity in crude tissue extracts was detected with PrSCh followed by ASCh, while values obtained with BSCh were apparently low, except in A. noae adductor muscle. The enzyme activity in A. noae gills and V. verrucosa gills and adductor muscle was significantly inhibited by BW254c51, but not with iso-OMPA. ChE activity in adductor muscle of A. noae was significantly reduced by both diagnostic inhibitors. The effect of organophosphorous pesticide trichlorfon on ChE activity was investigated in vitro in both species as well as in the gills of mussels Mytilus galloprovincialis. The highest sensitivity of ChE to trichlorfon was observed in A. noae gills and adductor muscle (IC50 1.6×10(-7)M and 1.1×10(-7)M, respectively), followed by M. galloprovincialis gills (IC50 1.0×10(-6)M) and V. verrucosa gills and adductor muscle (IC50 1.7×10(-5)M and 0.9×10(-5)M, respectively). The results of this study suggest the potential of ChE activity measurement in the tissues of A. noae as effective biomarker of OP exposure in marine environment.

  15. Molecular phylogenetics and systematics of the bivalve family Ostreidae based on rRNA sequence-structure models and multilocus species tree.

    Directory of Open Access Journals (Sweden)

    Daniele Salvi

    Full Text Available The bivalve family Ostreidae has a worldwide distribution and includes species of high economic importance. Phylogenetics and systematic of oysters based on morphology have proved difficult because of their high phenotypic plasticity. In this study we explore the phylogenetic information of the DNA sequence and secondary structure of the nuclear, fast-evolving, ITS2 rRNA and the mitochondrial 16S rRNA genes from the Ostreidae and we implemented a multi-locus framework based on four loci for oyster phylogenetics and systematics. Sequence-structure rRNA models aid sequence alignment and improved accuracy and nodal support of phylogenetic trees. In agreement with previous molecular studies, our phylogenetic results indicate that none of the currently recognized subfamilies, Crassostreinae, Ostreinae, and Lophinae, is monophyletic. Single gene trees based on Maximum likelihood (ML and Bayesian (BA methods and on sequence-structure ML were congruent with multilocus trees based on a concatenated (ML and BA and coalescent based (BA approaches and consistently supported three main clades: (i Crassostrea, (ii Saccostrea, and (iii an Ostreinae-Lophinae lineage. Therefore, the subfamily Crassostreinae (including Crassostrea, Saccostreinae subfam. nov. (including Saccostrea and tentatively Striostrea and Ostreinae (including Ostreinae and Lophinae taxa are recognized [corrected]. Based on phylogenetic and biogeographical evidence the Asian species of Crassostrea from the Pacific Ocean are assigned to Magallana gen. nov., whereas an integrative taxonomic revision is required for the genera Ostrea and Dendostrea. This study pointed out the suitability of the ITS2 marker for DNA barcoding of oyster and the relevance of using sequence-structure rRNA models and features of the ITS2 folding in molecular phylogenetics and taxonomy. The multilocus approach allowed inferring a robust phylogeny of Ostreidae providing a broad molecular perspective on their systematics.

  16. eDNA and specific primers for early detection of invasive species--A case study on the bivalve Rangia cuneata, currently spreading in Europe.

    Science.gov (United States)

    Ardura, Alba; Zaiko, Anastasija; Martinez, Jose L; Samulioviene, Aurelija; Semenova, Anna; Garcia-Vazquez, Eva

    2015-12-01

    Intense human activities facilitate the successful spread and establishment of non-indigenous aquatic organisms in marine and freshwater ecosystems. In some cases such intrusions result in noticeable and adverse changes in the recipient environments. In the Baltic Sea, the discovery and rapid initial spread of the North American wedge clam Rangia cuneata represents a new wave of invasion which may trigger unpredictable changes of the local benthic communities. In this study we present a species-specific DNA-based marker developed in silico and experimentally tested on environmental samples. Marker specificity and sensitivity were assessed in vitro from water samples containing different mixtures of the target species and other five bivalves currently present in the region: the native Cerastoderma glaucum, Macoma balthica and Mytilus trossulus, the invasive Dreissena polymorpha and the cryptogenic Mya arenaria. Cross-species amplification was not found in any case. The method allows to detecting at least 0.4 ng of R. cuneata DNA per μl, and 0.1 g of tissue per liter of water. Finally, the marker performance was assessed in water samples from the Baltic Sea and Vistula Lagoon. The coincidence between independent visual observations of R. cuneata and positive PCR amplification of the marker from the water samples confirmed the efficiency of this highly reproducible, fast, and technically easy method. R. cuneata traces can be detected from environmental DNA even when the population is sparse and small, enabling rapid management responses and allowing to track the invasion dynamics.

  17. The genome of the intracellular bacterium of the coastal bivalve, Solemya velum: A blueprint for thriving in and out of symbiosis

    Energy Technology Data Exchange (ETDEWEB)

    Dmytrenko, Oleg; Russell, Shelbi L.; Loo, Wesley T.; Fontanez, Kristina M.; Liao, Li; Roeselers, Guus; Sharma, Raghav; Stewart, Frank J.; Newton, Irene L. G.; Woyke, Tanja; Wu, Dongying; Lang, Jenna Morgan; Eisen, Jonathan A.; Cavanaugh, Colleen M.

    2014-09-25

    Background: Symbioses between chemoautotrophic bacteria and marine invertebrates are rare examples of living systems that are virtually independent of photosynthetic primary production. These associations have evolved multiple times in marine habitats, such as deep-sea hydrothermal vents and reducing sediments, characterized by steep gradients of oxygen and reduced chemicals. Due to difficulties associated with maintaining these symbioses in the laboratory and culturing the symbiotic bacteria, studies of chemosynthetic symbioses rely heavily on culture independent methods. The symbiosis between the coastal bivalve, Solemya velum, and its intracellular symbiont is a model for chemosynthetic symbioses given its accessibility in intertidal environments and the ability to maintain it under laboratory conditions. To better understand this symbiosis, the genome of the S. velum endosymbiont was sequenced. Results: Relative to the genomes of obligate symbiotic bacteria, which commonly undergo erosion and reduction, the S. velum symbiont genome was large (2.86 Mb), GC-rich (50.4percent), and contained a large number (78) of mobile genetic elements. Comparative genomics identified sets of genes specific to the chemosynthetic lifestyle and necessary to sustain the symbiosis. In addition, a number of inferred metabolic pathways and cellular processes, including heterotrophy, branched electron transport, and motility, suggested that besides the ability to function as an endosymbiont, the bacterium may have the capacity to live outside the host. Conclusions: The physiological dexterity indicated by the genome substantially improves our understanding of the genetic and metabolic capabilities of the S. velum symbiont and the breadth of niches the partners may inhabit during their lifecycle

  18. The genome of the intracellular bacterium of the coastal bivalve, Solemya velum: a blueprint for thriving in and out of symbiosis

    Energy Technology Data Exchange (ETDEWEB)

    Dmytrenko, Oleg; Russell, Shelbi L.; Loo, Wesley T.; Fontanez, Kristina M.; Liao, Li; Roeselers, Guus; Sharma, Raghav; Stewart, Frank J.; Newton, Irene LG; Woyke, Tanja; Wu, Dongying; Lang, Jenna; Eisen, Jonathan A.; Cavanaugh, Colleen M.

    2014-01-01

    Background: Symbioses between chemoautotrophic bacteria and marine invertebrates are rare examples of living systems that are virtually independent of photosynthetic primary production. These associations have evolved multiple times in marine habitats, such as deep-sea hydrothermal vents and reducing sediments, characterized by steep gradients of oxygen and reduced chemicals. Due to difficulties associated with maintaining these symbioses in the laboratory and culturing the symbiotic bacteria, studies of chemosynthetic symbioses rely heavily on culture independent methods. The symbiosis between the coastal bivalve, Solemya velum, and its intracellular symbiont is a model for chemosynthetic symbioses given its accessibility in intertidal environments and the ability to maintain it under laboratory conditions. To better understand this symbiosis, the genome of the S. velum endosymbiont was sequenced. Results: Relative to the genomes of obligate symbiotic bacteria, which commonly undergo erosion and reduction, the S. velum symbiont genome was large (2.86 Mb), GC-rich (50.4percent), and contained a large number (78) of mobile genetic elements. Comparative genomics identified sets of genes specific to the chemosynthetic lifestyle and necessary to sustain the symbiosis. In addition, a number of inferred metabolic pathways and cellular processes, including heterotrophy, branched electron transport, and motility, suggested that besides the ability to function as an endosymbiont, the bacterium may have the capacity to live outside the host. Conclusions: The physiological dexterity indicated by the genome substantially improves our understanding of the genetic and metabolic capabilities of the S. velum symbiont and the breadth of niches the partners may inhabit during their lifecycle

  19. Tissue partitioning of micro-essential metals in the vent bivalve Bathymodiolus azoricus and associated organisms (endosymbiont bacteria and a parasite polychaete) from geochemically distinct vents of the Mid-Atlantic Ridge

    Science.gov (United States)

    Kádár, Enikõ; Costa, Valentina; Santos, Ricardo S.; Powell, Jonathan J.

    2006-07-01

    Hydrothermal communities are built on highly specialised organisms possessing effective adaptation mechanisms to tolerate elevated levels of toxic heavy metals typical of these extreme habitats. Bioavailability and tissue compartmentalisation of micro-essential metals (Cu, Zn, and Fe) were investigated in the bivalve Bathymodiolus azoricus from three geochemically distinct hydrothermal vents (Rainbow, Lucky Strike, Menez Gwen). Additionally , in order to make inferences on the effect of biological interactions on the metal uptake, the bivalves' endosymbiont bacteria and commensal parasite Branchipolynoe seepensis were analysed for metal bioaccumulation. Micro-essential metal concentrations in byssus threads exceeded many-fold concentrations in the gill and digestive gland, which in turn were consistently one order of magnitude above levels measured in the mantle. In spite of its high metal concentrations, the byssus is unlikely to be an active bioaccumulator. Its high surface to mass ratio and its binding sites for metals suggest a reversible adsorption of micro-essential metals in the vent mussel. Inter-site comparison showed highest Fe concentrations in tissues of mussels from the Rainbow site, whereas Zn and Cu in all tissues were highest in mussels from the Lucky Strike site, reflecting metal concentrations in the water surrounding macro-invertebrates at these vent sites. The omnipresence of the commensal parasite polychaete in gills of B. azoricus from the Lucky Strike vent field, unlike the other sites, is suggested to be an adaptation to the typically elevated Fe concentrations in the water column near mussel beds. Unprecedented Fe concentrations measured in the digestive gland of mussels from the Rainbow site (4000 μg g - 1 , three times higher than levels in bivalves from polluted sites) call for further post-capture ecotoxicological investigations of potentially novel Fe-handling strategies. We provide the first information on the bioaccumulation

  20. Prospective study of 158 adult scoliosis treated by a bivalve polyethylene overlapping brace and reviewed at least 5 years after brace fitting

    Directory of Open Access Journals (Sweden)

    Jean Claude de Mauroy

    2016-10-01

    Full Text Available Abstract Background The conservative orthopaedic treatment of adult scoliosis is very disappointing. In a series of 144 patients; only 25 % (33 cases were monitored at 2 years of treatment. (Papadopoulos 2013. Thereby the literature typically focuses on a small number of patients, which limits the usefulness and relevance of its results. The brace effect on pain has been systematically described, but there is no publication on the effect of treatment on the Cobb angle and main clinical parameters. Methods From a prospective database started in 1998, we selected all 158 consecutive patients effectively treated conservatively with the Lyon management treatment and controlled five years after brace fitting. Lyon management includes a lordosing bivalve polyethylene overlapping brace in association with specific physiotherapy. The brace can either be short with anterior support under the chest or long with sterno-clavicular support when there is a high thoracic kyphosis. Results 1. For the rate of scoliosis controlled after 5 years, the follow-up was 24 % of the 661 patients accepting the treatment. Pain is almost the main reason for the medical consultation, generally correlating with an increase of the scoliotic angulation. 2. The descriptive data can be superimposed on general group with age (m=56 years, SD=13 but initial Cobb angulation is significantly higher (m=40°, SD=17. Ratio Female/Male=0.91. Generally, the scoliosis is stabilized at (m=39.74 °, SD=19.40, 8 years after the beginning of the treatment. 38 improvements of more than 5°= 24 %; 88 stable = 56 %; 32 worsening of more than 5° = 20 % The rib hump is improved of by 3 mm, (modelling effect of the brace. The occipital axis is improved by more than 6 mm. But the T1 plumb line distance is worsening by 7 mm (most braces are short without sterno-clavicular support. Conclusions For the first time, the number of records and follow up after 8 years allows to study the

  1. Taxonomy, distribution and population structure of invasive Corbiculidae (Mollusca, Bivalvia in the Suquía River basin, Córdoba, Argentina

    Directory of Open Access Journals (Sweden)

    Paola B. Reyna

    2013-06-01

    Full Text Available Invasive species are one of the most significant causes of biodiversity loss and changes in ecosystem services, which underlines the importance of their detection and their study. The Asian clams (Corbiculidae are invasive organisms that accidentally entered the La Plata River, Argentina, presumably in the 1960s. The objectives of the present study were to identify the corbiculid species and to determine their distribution at several locations along the Suquía River basin, an extended area in central Argentina. In addition, population structure was evaluated monthly during one year, at a site in the city of Córdoba that is characterized by high human influence. The presence of Corbicula fluminea (Müller, 1774 and Corbicula largillierti (Philippi, 1844 in the Suquía River basin is reported for the first time. The former species was found only in a lentic environment (San Roque reservoir, while the latter was also found along the tributary rivers and brooks of the basin. Corbicula largillierti showed variations in average density between the different sites and also in biomass and size classes throughout the study period at the site at Córdoba city. The relative composition of the sediments, flow fluctuation and human pollution may be responsible for the observed differences.

  2. Determinaçao de metais classificados como de importância toxicológica no molusco bivalve Anadara notabilis (Röding, 1798: Encontrado em Galinhos, Rio grande do norte, Brasil Determination of metals of toxicological importance in the bivalve Anadara notabilis (Röding, 1798 of Galinhos, coast of Rio grande do norte, Brazil

    Directory of Open Access Journals (Sweden)

    Marcos A Urbano de Araújo

    2010-12-01

    Full Text Available Os moluscos bivalves são consumidos por todo o mundo, constituindo-se em um recurso natural de boa aceitação pela população. Foi escolhido o molusco Anadara notabilis (conhecido como Xibiu ou Búzio para este trabalho pelo seu tamanho característico, bem maior que os mariscos mais comuns, e também por não ter sido encontrado na literatura nenhuma informação toxicológica sobre esta classe de moluscos. Todos os íons metálicos foram determinados por espectroscopia de emissão ótica com plasma indutivamente acoplado (ICP-OES descrito pela metodologia U.S. EPA 6010C. Os resultados mostraram que estiveram presentes no molusco vários metais de caráter tóxico, porém apenas o cromo obteve valor acima do permitido pela legislação brasileira. Dentre os metais classificados como tóxicos o cobre que apresentou valor de 5,7 mg/Kg, o níquel que apresentou teor de 4,23 mg/Kg e o cromo, o único acima dos valores permitidos pela legislação brasileira, com teor de 1,7 mg/Kg, sempre considerando a amostra in natura. Como os moluscos têm a propriedade de acumular metais em seu organismo, para o consumo desse tipo de alimento, deve-se tomar cuidado com as áreas próximas de sua coleta ou se cultivado, é necessário prevenir fatores que influenciem em sua contaminação.Bivalve molluscs are consumed throughout the world, constituting a natural resource with good acceptance by the population. The mollusc Anadara notabilis (know as eared ark was chosen for this study due to its characteristic size, much larger than most common shellfish, and the lack of toxicological information found in literature for this class of mollusks when considering metal ions toxicity. Metal ions were measured by inductively coupled plasma optical emission spectroscopy (ICP-OES, method described by U.S. EPA 6010C. Results showed that several toxic metals were present in shellfish, however only chrome was measured in levels higher than those allowed by Brazilian

  3. Molecular cloning and expression study of pi-class glutathione S-transferase (pi-GST) and selenium-dependent glutathione peroxidase (Se-GPx) transcripts in the freshwater bivalve Dreissena polymorpha.

    Science.gov (United States)

    Doyen, Périne; Bigot, Aurélie; Vasseur, Paule; Rodius, François

    2008-01-01

    Glutathione S-transferases (GST) and glutathione peroxidases (GPx) are essential components of cellular detoxification systems. We identified GST and GPx transcripts in the freshwater bivalve Dreissena polymorpha, their full-length coding sequences were obtained by reverse-transcription PCR using degenerated primers followed by 5' and 3' RACE-PCR (rapid amplification of cDNA ends-PCR). The cDNA identified encoded proteins of 205 and 243 amino acids corresponding respectively to a pi-class GST and a selenium-dependent GPx. The comparison of the deduced amino acid sequences with GST and GPx from other species showed that the residues essential to the enzymatic function of these two proteins are highly conserved. We studied their expression pattern in the digestive gland, the gills and the excretory system of D. polymorpha. The results showed that pi-GST mRNA expression is higher in the digestive gland than in the gills or the excretory system. Se-GPx transcripts are expressed at high, medium and very low levels in the digestive gland, the excretory system and the gills, respectively.

  4. Evaluation of Using Caged Clams to Monitor Contaminated Groundwater Exposure in the Near-Shore Environment of the Hanford Site 300 Area

    Energy Technology Data Exchange (ETDEWEB)

    Larson, Kyle B.; Poston, Ted M.; Tiller, Brett L.

    2008-01-31

    The Asiatic clam (Corbicula fluminea) has been identified as an indicator species for locating and monitoring contaminated groundwater in the Columbia River. Pacific Northwest National Laboratory conducted a field study to explore the use of caged Asiatic clams to monitor contaminated groundwater upwelling in the 300 Area near-shore environment and assess seasonal differences in uranium uptake in relation to seasonal flow regimes of the Columbia River. Additional objectives included examining the potential effects of uranium accumulation on growth, survival, and tissue condition of the clams. This report documents the field conditions and procedures, laboratory procedures, and statistical analyses used in collecting samples and processing the data. Detailed results are presented and illustrated, followed by a discussion comparing uranium concentrations in Asiatic clams collected at the 300 Area and describing the relationship between river discharge, groundwater indicators, and uranium in clams. Growth and survival, histology, and other sources of environmental variation also are discussed.

  5. In Vitro Acylation of Okadaic Acid in the Presence of Various Bivalves’ Extracts

    Directory of Open Access Journals (Sweden)

    Mari Yotsu-Yamashita

    2013-01-01

    Full Text Available The dinoflagellate Dinophysis spp. is responsible for diarrhetic shellfish poisoning (DSP. In the bivalves exposed to the toxic bloom of the dinoflagellate, dinophysistoxin 3 (DTX3, the 7-OH acylated form of either okadaic acid (OA or DTX1, is produced. We demonstrated in vitro acylation of OA with palmitoyl CoA in the presence of protein extract from the digestive gland, but not other tissues of the bivalve Mizuhopecten yessoensis. The yield of 7-O-palmitoyl OA reached its maximum within 2 h, was the highest at 37 °C followed by 28 °C, 16 °C and 4 °C and was the highest at pH 8 in comparison with the yields at pH 6 and pH 4. The transformation also proceeded when the protein extract was prepared from the bivalves Corbicula japonica and Crassostrea gigas. The OA binding protein OABP2 identified in the sponge Halichondria okadai was not detected in the bivalve M. yessoensis, the bivalve Mytilus galloprovincialis and the ascidian Halocynthia roretzi, though they are known to accumulate diarrhetic shellfish poisoning toxins. Since DTX3 does not bind to protein phosphatases 1 and 2A, the physiological target for OA and DTXs in mammalian cells, the acylation of DSP toxins would be related to a detoxification mechanism for the bivalve species.

  6. Structure and spatial patterns of macrobenthic community in Tai Lake, a large shallow lake, China

    Science.gov (United States)

    Di Li,; Erickson, Richard A.; Song Tang,; Xuwen Li,; Zhichun Niu,; Xia Wang,; Hongling Liu,; Hongxia Yu,

    2016-01-01

    Tai Lake (Chinese: Taihu), the third-largest freshwater lake in China, suffers from harmful cyanobacteria blooms that are caused by economic development and population growth near the lake. Several studies have focused on phytoplankton in Tai Lake after a drinking water crisis in 2007; however, these studies primarily focused on microcystin bioaccumulation and toxicity to individual species without examining the effects of microcystin on macrobenthic community diversity. In this study, we conducted a survey of the lake to examine the effects of microcystine and other pollutants on marcobenthic community diversity. A totally of forty-nine species of macroinvertebrates were found in Tai Lake. Limnodrilus hoffmeisteri and Corbicula fluminea were the most abundant species. Cluster-analysis and one-way analysis of similarity (ANOSIM) identified three significantly different macrobenthic communities among the sample sites. More specifically, sites in the eastern bays, where aquatic macrophytes were abundant, had the highest diversity of macrobenthic communities, which were dominated by Bellamya aeruginosa, Bellamya purificata, L. hoffmeisteri, and Alocinma longicornis. Sites in Zhushan Bay contained relatively diverse communities, mainly composed of L. hoffmeisteri, C. fluminea, L. claparederanus, R. sinicus, and Cythura sp. Sites in the western region, Meiliang Bay and Wuli Bay had the lowest diversity, mainly composed ofL. hoffmeisteri, C. fluminea, Branchiura sowerbyi, and Rhyacodrilus sinicus. In addition, the relationships between macrobenthic metrics (Shannon–Wiener, Margalef, and Pielou) and environmental variables showed that community structure and spatial patterns of macrobenthos in Tai Lake were significantly influenced by chemical oxygen demand (CODCr), biochemical oxygen demand (BOD5), lead (Pb), and microcystin-LR (L for leucine and R for arginine). Our findings provide critical information that could help managers and policymakers

  7. Field and laboratory assessment of a coal processing effluent in the Leading Creek Watershed, Meigs County, Ohio

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, A.J.; Cherry, D.S.; Currie, R.J. [Virginia Polytechnique Institute & State University, Blacksburg, VA (USA). Dept. of Biology

    2003-04-01

    The U.S. Environmental Protection Agency has not recommended water quality criteria (WQC) to protect aquatic life from elevated sodium and sulfate concentrations, such as those associated with the coal-processing effluent of Meigs County Mine No. 31. This discharge, received by a tributary of the Leading Creek Watershed (SE Ohio), had a mean specific conductivity (SC) of 8,109 (7,750-8,750) {mu}S/cm and total metal concentrations below acute WQC. The mean 48h LC50 for Ceriodaphnia dubia in the effluent was 6,713 +/- 99 {mu}S/cm; mean 48h survival was 44% for study sites downstream of the effluent. The best indicators of impairment used in this study were Ceriodaphnia fecundity, in situ Corbicula fluminea growth, EPT minus Hydropsychidae (richness and relative abundance), and relative Ephemeroptera abundance. Mayflies, reduced by more than 99% below the effluent, were absent from all but the furthest downstream study site. SC was strongly correlated with Corbicula growth and EPT minus Hydropsychidae richness, suggesting the effluent was primarily responsible for biotic impairment. The results indicated that SC levels, a measure of dissolved solids, in the Leading Creek Watershed that exceeded about to 3,700 {mu}S/cm impaired sensitive aquatic fauna.

  8. A malacological survey in the Manso Power Plant, State of Mato Grosso, Brazil: new records of freshwater snails, including transmitters of schistosomiasis and exotic species

    Directory of Open Access Journals (Sweden)

    Monica Ammon Fernandez

    2014-07-01

    Full Text Available Introduction Schistosomiasis is a parasitic disease of public health concern in Brazil, and the construction of hydroelectric dams, in addition to increasing permanent human settlement and tourism, has created conditions suitable for the establishment of mollusks that can transmit schistosomiasis. Such areas require a number of actions to prevent the establishment of schistosomiasis. This paper reports on a freshwater malacological survey carried out in the geographical area of the Manso Power Plant. Methods Mollusks were collected in 18 municipalities in the State of Mato Grosso between February 2002 and February 2004 (qualitative study and from April 2009 to February 2011 (quantitative study. Results Thirty-one species of mollusks were collected, including newly recorded species (Antillorbis nordestensis and Burnupia ingae. In addition, the geographic distributions of known species, including Biomphalaria straminea, a snail vector of Schistosoma mansoni, were expanded. A total of 4,507 specimens were collected in the APM Manso reservoir (Usina Hidrelétrica de Aproveitamento Múltiplo de Manso during the quantitative study, and Biomphalaria amazonica was found in six of the 10 localities analyzed. The Afroasiatic species Melanoides tuberculata, introduced after February 2009, was the dominant species (relative abundance 94.96%. Conclusions The study area is epidemiologically important due to the occurrence of B. straminea and B. amazonica, which are vectors of schistosomiasis, and M. tuberculata, a snail host of Centrocestus formosanus, which is responsible for centrocestiasis transmission. Observations of M. tuberculata and the exotic freshwater clams Corbicula fluminea and Corbicula largillierti raise concerns about biodiversity.

  9. An isotope mass balance model for the correlation of freshwater bivalve shell (Unio pictorum carbonate δ18O to climatic conditions and water δ18O in Lake Balaton (Hungary

    Directory of Open Access Journals (Sweden)

    Gabriella SCHÖLL-BARNA

    2011-08-01

    Full Text Available The oxygen isotope composition of bivalve shells (δ18Oshell can potentially record environmental variability of shallow lakes and therefore it has been extensively used as a proxy in the reconstruction of past climate and environmental conditions. As δ18Oshell reflects - besides the water temperature - the oxygen isotope composition of lake water (δ18OL, it is required to interpret the quality and impact of parameters influencing the δ18OL. Using the isotope mass balance model, I tested the hypothesis that Balaton lake water δ18O variability can be described as a result of the combined effects of three main climatic parameters such as river runoff, precipitation and evaporation. I calculated δ18OL time series for the period 1999-2008 for the whole water body at Siófok (eastern part of Lake Balaton, Hungary based on measured precipitation, inflow and evaporation amount and measured inflow, precipitation δ18O and calculated vapour δ18O data. The comparison of the modelled δ18OL time series to measured surface δ18OL data revealed that δ18O of Balaton water is sensitive for variation of climatic parameters. This variability is most striking at the surface, while according to the results of the model, the whole water body itself is less sensitive. Monthly differences suggest that generally during summer the whole water body is mixed up, while moderate isotope stratification (0.3-0.7‰ difference between surface and whole water body can be assumed in early spring and autumn. Predictions of shell δ18O values were made using the measured surface water δ18O data and the modelled δ18O values for the whole water body. High-resolution sampling was conducted on two Unio pictorum shells covering the period of 2001-2008, and both predictions were compared to measured shell δ18O records. The results showed that the prediction for the whole water body gives a better fit to the measured shell δ18O, suggesting that the whole water body better

  10. 淡水三角帆蚌贝壳珍珠质的同步辐射XRD研究%Synchrotron XRD Study on the Nacre of Freshwater Bivalve H.cumingii Lea

    Institute of Scientific and Technical Information of China (English)

    鄢晓晖; 王胜男; 杜博; 王小祥

    2012-01-01

    Synchrotron XRD was used to study internal stress of nacre and microstructure of individual nacre tablet in the shell of freshwater bivalve H. cumingii Lea. The diffraction patterns show some biopolymers (intra-crystalline organic matrix) are occluded inside nacre tablets during biomineralization, causing that nacre powder exhibits tensile-like internal stress which is strongly anisotropic along different vectors of the reciprocal lattice. The characteristic of internal stress suggests that the intra-crystalline organic matrix is most probably arranged in the specific form. And line profile analysis which is conducted with the synchrotron XRD patterns of heated and unheated nacre powder samples, further confirms that the intra-crystalline organic matrix is adsorbed on (002) atomic planes of nacre tablets. The findings will facilitate the study on the formation mechanism and the strengthening and toughening mechanism of the nacre and provide theoretical basis for designing new organic-inorganic composite with high performances and cultivating pearl.%利用同步辐射XRD研究淡水三角帆蚌贝壳珍珠质的内应力和珍珠质中单个文石板片的微结构,发现淡水三角帆蚌贝壳珍珠质中单个文石板片内存在晶内有机物,且该晶内有机物导致珍珠质层中产生拉应力.这一拉应力沿不同晶向呈现强烈的各向异性,表明晶内有机物在文石板片内很可能以某一特定的方式排列.同步辐射XRD图谱的线形分析进一步证实淡水三角帆蚌贝壳珍珠质中的晶内有机物吸附于文石板片的(002)晶面.这些研究结果将促进珍珠质矿化及强韧化机制的研究,为设计高性能无机-有机复合材料及培育珍珠提供科学的根据.

  11. Site-specific distribution of the bivalve

    NARCIS (Netherlands)

    Santos, S.; Aarts, G.M; Luttikhuizen, P.C.; Campos, J.; Piersma, T.; van der Veer, H.W.

    2012-01-01

    The development and maintenance of spatial patterns and the way they affect the dynamics of populations and ecosystems is a key issue in ecology. Since each individual and each species experiences the environment on a unique range of scales, it is vital to determine the spatial scales across which o

  12. Stable isotopes (δ 18O and δ 13C), trace and minor element compositions of Recent scleractinians and Last Glacial bivalves at the Santa Maria di Leuca deep-water coral province, Ionian Sea

    Science.gov (United States)

    Correa, Matthias López; Montagna, Paolo; Vendrell-Simón, Begoña; McCulloch, Malcolm; Taviani, Marco

    2010-03-01

    ' vital effect. The intercept of the δ 13C/δ 18O correlation line with the δ 13C DIC-composition permits recognition of δ 18O equilibrium values of aragonite and thus reconstruction of water temperatures despite strong disequilibrium precipitation. Since the environmental parameters ( T, S and δ 18O sw) are stable, the entire isotopic signal of the coral must be driven by biological fractionation and might reflect growth speed variations, potentially related to pH variations and changes in the saturation state of the calcifying fluid or seasonally varying nutrient availability. Laser ablation tracks show a trace element composition dependent to microstructural zones (fibrous aragonite vs. centres of calcification). The parabolic relation of the classical temperature proxies Mg/Ca and U/Ca point to trace element vital effects, rendering them unreliable in L. pertusa. The P/Ca ratio shows similar values as Desmophyllum dianthus, for which a linear dependence with seawater phosphate (DIP) has been previously demonstrated. Consequently L. pertusa might be an additional nutrient recorder at bathyal depths. From the same site we also analysed the stable isotopic composition of the Last Glacial pectinid bivalve Pseudamussium peslutrae, which has been radiocarbon-dated (AMS- 14C) at 26.3 ka 14C yr BP. The isotope values of the shell calcite document a strongly differing glacial temperature-salinity regime preceding the Holocene coral growth above a prominent hiatus.

  13. HISTOPATHOLOGICAL EXAMINATION OF BIVALVE MUSSEL HYRIOPSIS CUMINGII LEA ARTIFICIALLY INFECTED BY VIRUS%人工感染三角帆蚌病毒性疾病的组织病理学观察

    Institute of Scientific and Technical Information of China (English)

    钟蕾; 肖调义; 黄倢; 戴良英; 刘晓燕

    2011-01-01

    The pathogen Hyriopsis cumingii Plague Virus isolated from the diseased H. cumingii Lea has been artificially transferred to the healthy H. cumingii Lea. The infected H. cumingii Lea has displayed some typical pathological changes. Observations by histopathology have showed that most of organs including the digestive gland, stomach and intestine are the primary targets of the plague virus. Lesions have been observed, accompanied with a number of empty areas, cell vacuolization and some cells falling-off. Arenavirus-like particles have been detected by using transmission electron microscopic (TEM) examination on investigated organs of the artificially infected bivalve mussel Hyriopsis cumingii. Virions are spherical with a size of 120 nm in diameter, and the outer layer of the intact arenavirus-like particles have small protuberance and moderate electron-dense nucleicapsid. Under electronic microscope, the most obvious cellular pathologic feature is the large vacuole areas of cytoplasm, and there is the reduction or devoid of organelles in the cytoplasm. Varying degrees of denaturalization and necrosis have been found in the intestinal mucosa epithelial cells.We have also observed that in cytopathic cells of digestive gland, the nuclei has been discovered to be amorphous and hypertrophied. There are denaturalization and necrosis in the epithelial cell of gill and the nucleus membrane of granulocytes have been dissolved.%从自然发病的病蚌中提取出病毒,经人工感染健康三角帆蚌后呈现出典型的病理变化.组织学观察显示消化腺、胃、肠、外套膜、斧足和鳃等均出现大量细胞空泡化、部分细胞肿大、上皮细胞排列不紧密,结缔组织不完整,部分细胞溶解甚至脱落等,表明它们均为病毒损害的主要靶器官.透射电镜观察显示大量砂样病毒存在于患病三角帆蚌不同器官中.病毒粒子为直径约120 nm的圆球形,表面具有明显的纤突,无囊膜结构.被感染细

  14. Assessing arsenic bioavailability through the use of bioassays

    Science.gov (United States)

    Diesel, E.; Nadimpalli, M.; Hull, M.; Schreiber, M. E.; Vikesland, P.

    2009-12-01

    Various methods have been used to characterize the bioavailability of a contaminant, including chemical extractions from soils, toxicity tests, bioaccumulation measurements, estimation from soil properties, in vitro/in vivo tests, and microbial biossays. Unfortunately, these tests are all unique (i.e. they measure bioavailability through different mechanisms) and it is difficult to compare measurements collected using one method to those collected from another. Additionally, there are fundamental aspects of bioavailability research that require further study. In particular, changes in bioavailability over time are not well understood, as well as what the geochemical controls are on changes in bioavailability. In addition, there are no studies aimed at the integration of bioavailability measurements and potential geochemical controls. This research project seeks to find a standard set of assays and sensors that can be used to assess arsenic bioavailability at any field site, as well as to use these tools and techniques to better understand changes in, and controls on, arsenic bioavailability. The bioassays to be utilized in this research are a bioluminescent E. coli assay and a Corbicula fluminea (Asian clam) assay. Preliminary experiments to determine the suitability of the E. coli and C. fluminea assays have been completed. The E. coli assay can be utilized to analyze As(III) and As(V) with a linear standard curve between 5 and 200 ppb for As(III) and 100 ppb and 5 ppm for As(V); no bioluminescent response above background was elicited in the presence of Roxarsone, an organoarsenical. The C. fluminea assay is capable of bioaccumulating As(III), As(V), Roxarsone, and MSMA, with As(III) being the most readily accumulated, followed by As(V), Roxarsone and MSMA, respectively. Additional research will include assessing bioavailability of various arsenic species adsorbed to natural colloidal materials (i.e. clays, iron oxides, NOM) to the E. coli and C. fluminea assays

  15. New method for control of biological fouling in pipelines based on elevated partial pressures of carbon dioxide or combustion exhaust gases.

    Energy Technology Data Exchange (ETDEWEB)

    B.J. Watten; R.E. Sears; R.F. Bumgardner [U.S. Geological Survey - Leetown Science Center, Kearneysville, WV (United States)

    2005-07-01

    Zebra mussels (Dreissena polymorpha) and Asian clams (Corbicula fluminea) are major macro fouling species of water conduits used in industrial and power station raw water/condensor systems. Control typically involves manual scraping and use of thermal treatment, deoxygenation or biocides. The costs of control and system damage resulting from fouling in the United States alone have been estimated at $1 billion/year. There is a pressing need for new economical and safe control strategies. Aquatic species in general are intolerant to increases in PCO{sub 2} given its effect on water, blood and hemolymph pH. These species are also sensitive to increases in elevated total dissolved gas pressure. The gas bubble disease that develops following exposure can, as with CO{sub 2} exposure, lead to mortality. We are exploiting this sensitivity by developing a control method based on manipulation of PCO{sub 2} or power plant exhaust gas (CO{sub 2}, 14%; SO{sub 2}, 0.3%), i.e., the supersaturation of hemolymph and tissues with gas followed by an induced (short term) pressure release designed to induce formation of gas emboli. SO{sub 2} present in stack gas acts with CO{sub 2} to reduce water and hemolymph pH so as to reduce required exposure periods. System effluents are degassed, CO{sub 2} recovered and pH adjusted if needed with alkaline reagents. Test results indicate the new process is effective at controlling C. fluminea as well as other target species, including crustaceans and fish. Required exposure periods (LT50) are short and decrease with increasing gas supersaturation levels. Gas recovery and reuse methods developed have reduced gas requirements by 85% making the method attractive economically and environmentally. 40 refs., 8 figs., 1 tab.

  16. Selective Feeding on Five Species of Bivalves and Feeding Rhythm of Asterias amurensis%多棘海盘车(Asterias amurensis)对5种双壳贝类的摄食选择性及摄食节律

    Institute of Scientific and Technical Information of China (English)

    代克涛; 李娇; 关长涛; 张媛; 赵学伟

    2015-01-01

    研究了多棘海盘车(Asterias amurensis)对虾夷扇贝(Patinopecten yessoensis)、栉孔扇贝(Chlamys farreri)、褶牡蛎(Ostrea plicatula)、贻贝(Mytilus galloprovincialis)、菲律宾蛤仔(Ruditapes philippinarum)5种双壳贝类的摄食选择性和对栉孔扇贝的摄食节律。结果显示,在有或无日本蟳、刺参等干扰饵料的条件下,多棘海盘车对于5种双壳贝类均可摄食,且表现出明显的摄食选择性。其中,多棘海盘车对菲律宾蛤仔的摄食选择性均显著高于其他4种贝类(P<0.05),分别为5.7、5.0、5.7、5.3、6.0只/d,干扰饵料的加入并没有对多棘海盘车的摄食选择性造成显著影响。同时,采用定时投喂饵料的方式,每隔4 h投喂一次栉孔扇贝,多棘海盘车表现出显著地昼夜摄食节律。其18:00–翌日06:00的摄食量显著高于06:00–18:00的摄食量(P<0.05),分别为60%和40%,多棘海盘车的摄食高峰出现在18:00–22:00,摄食频率达到58%,显著高于其他时段(P<0.05)。%Asterias amurensis is one of the primary predators of bivalves that often cause massive death of cultured bivalves. Better understanding of the feeding ecophysiology of A. amurensis is the key for developing effective control strategies. In this study, we recorded the selective feeding and feeding rhythm of A. amurensis on five species of bivalves including Patinopecten yessoensis, Chlamys farreri, Ostrea plicatula, Mytilus galloprovincialis and Ruditapes philippinarum, and thus identified the characteristics of feeding of A. amurensis. The experimental animals were collected from the sea area of Zhangzi Island and then transported to our seaside laboratory at low temperature. The A. amurensis was acclimated to laboratory conditions for 10 d before the experiment. The experiment was conducted between October 22 and November 12, 2013, at the water temperature of 13−15℃, and at the salinity of 30−31, and at the dissolved

  17. Diet and population metrics of the introduced blue catfish population in the Altamaha, River, GA

    Science.gov (United States)

    Bonvechio, Timothy F.; Jennings, Cecil A.

    2011-01-01

    Blue catfish (Ictalurus furcatus) were first detected in the Altamaha River, Georgia, during an access creel survey in 2005 and subsequently in 2006 during annual ictalurid sampling. Introduction of this species in the Altamaha River is believed to have occurred via escape from normal upstream reservoir releases from Lake Sinclair and Lake Oconee. Relative abundance, as indexed by electrofishing catch rate (fish per hour), has increased from 2.9±1.0 SE in 2006 to 38.8±8.2 SE in 2011. The size of blue catfish captured ranged from 56 to 820 mm total length and 0.001 to 7.7 kg. Using otoliths obtained in 2010 (n=214), age of fish ranged from 0 to 6 yrs, which indicated a relatively young population. The catch-curve analysis resulted in an instantaneous mortality rate (Z) of 0.75. Despite concerns of blue catfish predation on native fishes and mussels, a diet analysis of blue catfish (n=257) obtained in 2010 revealed that diets of fish in all size groups were dominated by the introduced Asiatic clam (Corbicula fluminea). This study describes a recently introduced blue catfish population in an Atlantic coastal plain river and provides insight on possible ecological effects during the early phases of establishment. These results offer an early status assessment of the invasion dynamics before the system has had time to reach a new equilibrium state.

  18. Toxicity of a traditional molluscicide to asian clam veligers

    Science.gov (United States)

    Layhee, Megan J.; ,; Miho Yoshioka,; Bahram Farokhkish,; ,; Gross, Jackson A.; Sepulveda, Adam J.

    2014-01-01

    Aquaculture and hatchery industries are in need of effective control methods to reduce the risk of spreading aquatic invasive species, such as the Asian clam Corbicula fluminea, through aquaculture and hatchery activities. The planktonic nature of Asian clam veligers enables this life stage to enter water-based infrastructure undetected, including hatchery trucks used to stock fish. Once in hatchery trucks, veligers can disperse overland and establish in previously uninvaded habitats. As a result, there is a need to develop techniques that result in veliger mortality but do not harm fish. In September 2012, we conducted laboratory trials to determine if a molluscicide (750 mg/L potassium chloride and 25 mg/L formalin) commonly used to kill zebra mussel (Dreissena polymorpha) veligers in hatchery trucks can also effectively kill Asian clam veligers. We exposed Asian clam veligers to this molluscicide for 1, 3, and 5 h in each of two water types: deionized water and filtered lake water. We found ,20% mortality at the 1-h exposure period and 100% mortality at both the 3-h and 5-h exposure periods, regardless of water type. This laboratory study represents an important step toward reducing the spread of Asian clams by aquaculture facilities.

  19. Hábito alimentar e osteologia da boca do peixe-rei, Odontesthes humensis de Buen (Atheriniformes, Atherinopsidae na Lagoa Mirim, Rio Grande do Sul, Brasil Feeding habits and mouth osteology of silverside, Odontesthes humensis de Buen (Atheriniformes, Atherinopsidae in the Mirim Lagoon, Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Fábio Lameiro Rodrigues

    2001-09-01

    Full Text Available Gut contents of 304 individuals of the silverside Odontesthes humensis de Buen, 1953 were analyzed using frequency of occurrence (FO% and gravimetric (P% methods. A total of 207 individuals (68.1% had some food itens in the gut, while 97 individuals (31.9% had empty guts. The silverside Odontesthes humensis has presented a benthic carnivorous diet, preying mainly on molluscs and arthropods. The molluscs Heleobia sp. (FO = 61.35% and Corbicula fluminea (Müller, 1774 (FO = 57.97% were the most frequent itens, followed by Neocorbicula limosa (Maton, 1811 (FO = 17.39%. Among the arthropods, the coleoptera insects (FO= 18.84% were dominant followed by, insect larvae (FO = 6.76%, the crustacean Palaemonetes argentinus Nobili, 1901 (FO = 1.93% and isopods (FO = 1.45%. Vegetal remains, organic matter and digested fish were grouped due to low frequency (FO = 9.13% being considered occasional. Juvenile fed mainly on insect larvae and moluscs, while the adults preferred molluscs and coleoptera. On the description of its feeding apparatus the importance of a protrusible upper jaw was observed, being important on the capture of prey in inaccessible places. A protrusible mouth and the format of the pharingean plates, are important morphological characters that assist on the capture and handling of prey. The molariform shaped pharingean teeth help break hard food items, as shells and carapaces.

  20. Interspecific Relationships in Benthic Assemblages of a Large Lowland River : Co-existence or Competition as a Result of Habitat Characteristics

    Science.gov (United States)

    Akopian, M.; Usseglio-Polatera, P.

    2005-05-01

    Macrobenthic assemblages of the lower, regulated and canalized Marne River (France) are dominated by several "exotic", recently introduced species. Arrival, installation and spread of such alien species were certainly promoted by (1) the close connection between French and other European river systems (Rhine, Danube), (2) the modification of natural river flow and benthic habitats. Both habitat characteristics (e.g. granulometric composition, organic content) and corresponding benthic assemblage structure were analysed to identify the substrate affinity of major taxa in the lower Marne River. The main aim of the study was to evaluate the possible biotic interactions (i.e. competition for food and/or space) among dominant taxa as function of habitat features and to predict the future development of newly established species, already known as potential invaders: Corbicula fluminea (Bivalvia), Hypania invalida (Polychaeta), Chelicorophium curvispinum (Amphipoda), etc. Most of the newly established species, coming from the same biogeographical area ("invasional meltdown" hypothesis?), are eurytopic, with high fecundity and large food spectrum. First results demonstrated the co-existence of such species in the Marne River. But the future ecological importance of these organisms in benthic assemblages of the river depends on their present population size, population dynamics, and ability to colonize bottom substrates.

  1. Zebra mussels (Dreissena polymorpha) as a biomonitor of trace elements along the southern shoreline of Lake Michigan.

    Science.gov (United States)

    Shoults-Wilson, W Aaron; Elsayed, Norhan; Leckrone, Kristen; Unrine, Jason

    2015-02-01

    The invasive zebra mussel (Dreissena polymorpha) has become an accepted biomonitor organism for trace elements, but it has yet to be studied along the Lake Michigan shoreline. Likewise, the relationships between tissue concentrations of elements, organism size, and sediment concentrations of elements have not been fully explained. The present study found that a variety of allometric variables such as length, dry tissue mass, shell mass, organism condition indices, and shell thickness index were useful in explaining intrasite variability in elemental concentrations. The flesh condition index (grams of tissue dry mass per gram of shell mass) explained variability at the most sites for most elements. Once allometric intrasite variability was taken into account, additional significant differences were found between sites, although the net effect was small. Significant positive relationships between sediment and tissue concentrations were found for Pb and Zn, with a significant negative relationship for Cd. It was also found that Cu and Zn concentrations in tissues increased significantly along the shoreline in the southeasterly direction, whereas Hg increased in a northwesterly direction. Opportunistic sampling found that zebra mussels accumulate significantly higher concentrations of nearly all elements analyzed compared to Asian clams (Corbicula fluminea) at the same site. The present study demonstrates the need to fully explain natural sources of variability before using biomonitors to explain spatial distributions of trace elements.

  2. Ecological values of shallow-water habitats: Implications for the restoration of disturbed ecosystems

    Science.gov (United States)

    Lopez, C.B.; Cloern, J.E.; Schraga, T.S.; Little, A.J.; Lucas, L.V.; Thompson, J.K.; Burau, J.R.

    2006-01-01

    A presumed value of shallow-habitat enhanced pelagic productivity derives from the principle that in nutrient-rich aquatic systems phytoplankton growth rate is controlled by light availability, which varies inversely with habitat depth. We measured a set of biological indicators across the gradient of habitat depth within the Sacramento-San Joaquin River Delta (California) to test the hypothesis that plankton biomass, production, and pelagic energy flow also vary systematically with habitat depth. Results showed that phytoplankton biomass and production were only weakly related to phytoplankton growth rates whereas other processes (transport, consumption) were important controls. Distribution of the invasive clam Corbicula fluminea was patchy, and heavily colonized habitats all supported low phytoplankton biomass and production and functioned as food sinks. Surplus primary production in shallow, uncolonized habitats provided potential subsidies to neighboring recipient habitats. Zooplankton in deeper habitats, where grazing exceeded phytoplankton production, were likely supported by significant fluxes of phytoplankton biomass from connected donor habitats. Our results provide three important lessons for ecosystem science: (a) in the absence of process measurements, derived indices provide valuable information to improve our mechanistic understanding of ecosystem function and to benefit adaptive management strategies; (b) the benefits of some ecosystem functions are displaced by water movements, so the value of individual habitat types can only be revealed through a regional perspective that includes connectedness among habitats; and (c) invasive species can act as overriding controls of habitat function, adding to the uncertainty of management outcomes. ?? 2006 Springer Science+Business Media, Inc.

  3. 液相色谱结合串联质谱方法研究中国沿海贝类中脂溶性藻毒素的种类结构和分布规律%The Lipophilic Phycotoxins Profile and Distribution in Bivalve Shellfish of Chinese Coasts by High Performance Liquid Chromatography Coupled with Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    刘仁沿; 梁玉波; 刘磊; 樊东红; 许道艳; 孙茜

    2014-01-01

    A number of marine microalgae are known to produce toxins that can accumulate in shellfish, leading to food poisons and potentially fatal reactions of humans and other mammals consuming the contaminated shellfish. Lipophilic phycotoxins are dissolvable in organic solvents, and easily accumulated in animal adipose tissue. There are six common types lipophilic phycotoxins with variety of structures for each. This paper reported the profiles and distributions of lipophilic phycotoxins in 34 bivalve species from 55 stations along the coasts of China. Multiple types of lipophilic phycotoxins were detected in the bivalves along the coasts of China through the HPLC-MS/MS method, including Okadaic acid (OA), Pectenotoxin (PTXs), Azaspiracid (AZAs), Yessotoxin (YTXs)、Gymnodimine(GYM) and Spiroloides(SPX)etc. GYM was mostly observed in the coastal water of Guangdong, Guangxi and Hainan in South China Sea;YTXs, mainly present in Patinopecten yessoensis and Chlamys farreri, were detected only in Yellow Sea; while PTXs were mostly from the coast of Bohai. We observed three structures of PTXs, among which, the one had highest positive rate of 44% and maximum tissue concentration of 53.2 µg·kg-1 were PTX-2Sa; In terms of positive rate and tissue concentration, GYM (35.3%,39.1 µg·kg-1) followed PTX-2Sa. Similarly, three structures of YTXs were detected. And YTXs were present in the tissues of Patinopecten yessoensis in northern Yellow Sea throughout the year with a peak concentration in September. The geographic distributions of phycotoxins could be depended on the presence of toxic algae, while it was still unclear about the biological source of these three common lipophilic phycotoxins detected in the shellfish in China. Although the level of lipophilic phycotoxins in this study were lower than the regulated limitation for food safety, the work here reported the wide presence of variety of phycotoxins in the shellfish along the coasts of China, posing potential health

  4. Photonic crystal type structure in bivalve ligament of Pinctada maxima

    Institute of Scientific and Technical Information of China (English)

    ZHANG GangSheng

    2007-01-01

    The dry ligament of Pinctada maxima normally appears black; however, it can exhibit striking blue structural colors after being wetted by water. The field-mission SEM investigation shows that the ligament is made of lamellae, which, about 35 μm thick, are made of proteins and aragonite fibers of about 78 nm in diameter. In each single lamella, the fibers are highly aligned characterized by a 2D photonic crystal type structure. According to measured reflective spectra and theoretical simulations, the dry and wet ligaments possess photonic stop band at ultraviolet and blue wavelengths, respectively, which are responsible for structural colorations of ligament.

  5. Growth and other physiological responses of bivalves in laboratory experiments

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Milford lab maintains data sets relating to a variety of growth and physiology trials. These include husbandry techniques (i.e. stocking density, container size,...

  6. Worldwide lead-isotope ratio in bivalves and sediments

    DEFF Research Database (Denmark)

    Larsen, Martin Mørk; Jacobsen, Gitte; Strand, Jakob;

    The lead-isotope ratio have been used to assess and identify impact of leaded gasoline, coal combustion and  mineral activities[ref 1] due to the difference in 206Pb (~52%), 207Pb (~24%) and 208Pb (~23%) isotope ratios. The source of these differences is the decaying of the parent isotopes of 238U...... to 206Pb, 235U to 207Pb and 232Th to 208Pb. 204Pb is the only stable Pb isotope usually contributing 1% of the total Pb. Differences in 206Pb/207Pb ratio ranges from 1.06 to 1.10 in old Pb ores (e.g. the time of the roman empire), whereas recent mining from radiogenic (high U and Th contents) ores can...

  7. Light indirectly mediates bivalve habitat modification and impacts on seagrass

    DEFF Research Database (Denmark)

    Castorani, Max Christopher Nicholas; Glud, Ronnie N.; Hasler-Sheetal, Harald

    2015-01-01

    and plant responseswere measured. Light modified the effect of mussels on porewater ammonium, but eelgrass was not nutrient limited and, therefore, mussels did not enhance growth. Mussels increased sediment sulfides irrespective of light availability and, by reducing net oxygen flux (production...... and respiration),mussels and lowlight availability exacerbated sulfide intrusion of eelgrass tissues. Surprisingly, sulfide stress did not affect plant growth, survival, or energy stores. Thus, habitat modification by musselsmay represent a risk to eelgrass, especially during low productivity conditions...

  8. Fission products in shell of the freshwater bivalve Dreissena polymorpha

    Energy Technology Data Exchange (ETDEWEB)

    Zuykov, M.A.; Orlova, M.I.; Burakov, B.E.; Zamoryanskaya, M.V.; Anderson, E.B. [V.G.Khlopin Radium Institute, Lab. of Applied Mineralogy and Radiogeochemistry, Saint Petersburg (Russian Federation)

    2004-07-01

    Within activity of Bio-mineralogical group of KRI (RFBR no. 03-05-65195), dealing with distribution, accumulation and relations of radionuclides within shells of freshwater molluscs, a capacity to incorporating of {sup 137}Cs, {sup 85}Sr and {sup 241}Am into shells of Dreissena polymorpha, obtained after laboratory experiments was studied; and a distribution of Americium-241 in shell is preliminary discussed on the basis a cathodoluminescence (CL). Short-term uptake experiments were performed to understand difference in accumulation of radionuclides (Cs, Sr, Am) in high concentration which were added in the experimental solutions separately as well as in mixtures by molluscs. The data obtained suggest greater content of {sup 85}Sr than {sup 137}Cs and {sup 241}Am in all studied samples, thus the mixture of radionuclides had no effect on greater accumulation of Sr by the molluscs shell. The concentration of radionuclides in shells are following (in Bq/g): {sup 85}Sr - 5x10{sup 4}; {sup 137}Cs 1x10{sup 4}; {sup 241}Am 2x10{sup 4} (with maximum 1x10{sup 5}). Present data suggest also on high capacity for incorporating of these radionuclides in molluscs shells in laboratory conditions. The cathodoluminescent images on full section of Am-doped shells (containing about 0.00005 wt.% of Am) of D.polymorpha along a length of valve was characterized by light bands of blue-green color which are parallel to the shell surface and corresponded to different shell layers. Maximum intensity is corresponds to the layer boundaries characterised by concentration of organic component. However, this result should be treated with care due to the large uncertainty in the determination of the americium in organic and mineral components of mollusc shells separately, which is a subject of further investigations. (author)

  9. Marine pollution detection through biomarkers in marine bivalves

    Digital Repository Service at National Institute of Oceanography (India)

    Verlecar, X.N.; Pereira, N.; Desai, S.R.; Jena, K.B.; Snigdha

    , pollution, xenobiotics. W ASTE management strategies adopted in India have failed to keep pace with the industrial growth and urban i zation. This has resulted in the accumulation of contam i nants with a consequent loss in coastal marine... of domestic and industrial waste, the Hg content fluctuated b e tween 0.12 to 1.4 ?g/l, in sediments from 0.08 to 0.36 ?g/g dry wt an d in fish mu s cle at Thana Creek from 0.217 to 0.512 ?g/g wet wt 4 . Also, off Karwar (Karn a taka) Hg...

  10. Protandric hermaphroditism in the bivalve Arca noae (Mollusca: Arcidae

    Directory of Open Access Journals (Sweden)

    G. BELLO

    2013-04-01

    Full Text Available Following the histological analysis of Arca noae samples from the south-western Adriatic Sea, five hermaphroditic specimens were found out of 168 sexed individuals (3.0%. The hermaphrodite gonads showed the co-occurrence of male and female germ cells within the same acini, i.e. both spermatozoa in the lumen and oogonia lining its wall. Oogonia increased in size through winter, thus suggesting that the direction of sex change is from male to female. Both the biometrical analyses and theoretical considerations strongly suggest that A. noae is an obligate protandric species.

  11. Predicting Effects of Coastal Acidification on Marine Bivalve Populations

    Science.gov (United States)

    The partial pressure of carbon dioxide (pCO2) is increasing in the oceans and causing changes in seawater pH commonly described as ocean or coastal acidification. It is now well-established that, when reproduced in laboratory experiments, these increases in pCO2 can reduce survi...

  12. SURVIVAL ESTIMATES OF BYCATCH INDIVIDUALS DISCARDED FROM BIVALVE DREDGES

    Directory of Open Access Journals (Sweden)

    Francisco Leitão

    2014-12-01

    Full Text Available The fate of released bycatch is an issue of great interest for fisheries research and management. Survival experiments were carried out to assess the survival capacity of animals damaged and discarded during clam dredging operations. Three common bycatch species, two fish (Trachinus vipera; Dicologlossa cuneata and one crab (Polybius henslowii, were collected during the sorting of catches from a commercial dredging boat. An arbitrary score scale was used to quantify the type and extent of damage to the organisms. Onboard, damaged individuals were placed in tanks containing seawater which were subsequently transferred to the laboratory. Survival experiments were conducted during the subsequent 48h. D. cuneata exhibited the lowest mortality after 48h (54%, followed by P. henslowii (65% and T. vipera (81%. Despite the magnitude of the percentage mortalities determined, the average number of individuals estimated to die during a 15 minutes tow (standard commercial fishing time was relatively small: 1.2, 3.24 and 11 for D. cuneata, T. vipera and P. henslowii, respectively. Nevertheless, when these figures are extrapolated to cover all the dredging fleet the impact of this practice on the populations of the species studied can be significant, particulary for D. cuneata.

  13. Relationships between innate immunity in bivalve molluscs and environmental pollution

    Directory of Open Access Journals (Sweden)

    MI Girón-Pérez

    2010-06-01

    Full Text Available The immune system of invertebrates, such as molluscs consists of innate mechanisms very effective against antigens commonly present in the environment. However, these defense strategies could be altered by pollutants. This review is focused mainly on the effect of metals, PCB, pesticides, PAHs, and others environmental pollutant on immune response of molluscs.

  14. 体积排阻高效液相色谱-电感耦合等离子体质谱法测定海产贝类中镉的形态%Speciation Analysis of Cadmium in Marine Bivalves by Size Exclusion Chromatography-High Performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    赵艳芳; 尚德荣; 宁劲松; 翟毓秀

    2012-01-01

    The speciation analysis of cadmium in the scallop (Chlamys farreri, C. farreri) with high Cd accumulation capability and the clam (Ruditapes philippinarum, R. philippivarum) with low Cd accumulation capability was first conducted by size exclusion chromatography-high performance liquid chromatography-inductivcly coupled plasma mass spectrometry (SEC-HPLC-ICP-MS), and in vitro whole-bionic digestion model was used to determine the cadmium speciation in two bivalves under the action of saliva, the acidity of stomach and intestine with inorganic and organic components and diges-tion enzymes. The results showed that the total cadmium content in C. farreri was almost 10 times in R. philippinarum. Three Cd species, metallothionein (MT)-Cd, glutathione (GSH)-Cd and cystein (Cys)-Cd were detected in C. farreri, and two Cd species, MT-Cd and GSH-Cd were detected in R. philippinarum. According to the different peak areas, MT-Cd and GSH-Cd content in C. farreri was about 5. 6 and 2. 0 times of those in R. philippinarum respectively. Using in vitro whole-bionic diges-tion model, one unknown Cd species with small molecule (named Cd-X) was detected in whole-bionic digestion of gastric extracts, and four Cd species (mainly MT-Cd) were detected in the whole-bionic digestion of intestine extracts for C. farreri; however, for R. philippinarum, the unknown Cd-X was the main Cd species in both gastric and intestinal extracts. The experiment also proves that Cd can be separated from MT-Cd, GSH-Cd and Cys-Cd under the effect of the whole-bionic digestion of stomach and intestine.%运用体积排阻高效液相色谱-电感耦合等离子体质谱联用技术(SEC-HPLC-ICP-MS)分析了高镉积累扇贝和低镉积累菲律宾蛤仔中镉的存在形态,并结合体外全仿生消化技术,研究了在唾液、胃、肠无机物和有机物(含消化酶)作用下,扇贝和菲律宾蛤仔中镉的主要存在形态.结果发现:扇贝中Cd总量约为菲律宾蛤仔的10

  15. [Latin American malacology. Freshwater mollusks from Argentina].

    Science.gov (United States)

    Rumi, Alejandra; Gregoric, Diego E Gutiérrez; Núñez, Verónica; Darrigran, Gustavo A

    2008-03-01

    . Species of sanitary interest are the propagators of: schistosomiasis -Biomphalaria peregrina, B. straminea y B. tenagophila, Planorbidae-, fasciolasis -Lymnaea viatrix and L. columnella, Lymnaeidae- and dermatitis -Chilina gibbosa and C. fluminea, Chilinidae. Invasive species are: Corbicula fluminea (Corbiculidae) and Limnoperna fortunei (Mytilidae). The construction of new areas for the protection and conservation of the high risk endemic species of freshwater molluscs is a priority. It is necessary to give special attention to the species of the patagonic mountain range and of the mesopotamic area of the Del Plata Basin.

  16. Analysis and Evaluation on Nutritional Components of Three Freshwater Mussels from Zhejiang Province%浙江地区3种淡水经济贝类的营养成分分析与评价

    Institute of Scientific and Technical Information of China (English)

    郑汉丰; 李家乐

    2012-01-01

    采用国标方法对浙江地区的河蚬、环棱螺和圆田螺的营养成分进行分析并进行评价,以期为贝类的营养研究、饲料生产和开发利用提供理论依据.结果表明,环棱螺和圆田螺的水分、灰分、粗蛋白和粗脂肪的含量较为接近,而糖类的含量有较大差异;河蚬与环棱螺和圆田螺在主要营养成分组成方面差异较大.氨基酸分析结果表明,3种淡水经济贝类均含有18种氨基酸,其中包括人体必需的8种氨基酸,第一、二限制性氨基酸分别为缬氨酸和异亮氨酸.此外,谷氨酸含量远高于其他氨基酸,环棱螺中高达1 15.88 mg/g,圆田螺中也高达98.68 mg/g,2种螺肉的呈味氨基酸接近,含量均达40%以上.环棱螺和圆田螺的总氨基酸含量分别为653.28 mg/g和561.67 mg/g,必需氨基酸占总氨基酸的比例均在35%左右,与WHO/FAO模式推荐的模式(35.38%)接近.因此,3种淡水经济贝类软体部分的营养组成丰富,氨基酸种类齐全、比例均衡,具有较好的开发和利用价值.%The national standard methods was used to analyze and evaluate the nutrition components in the muscles of Corbicula fluminea, Bellamya aeruginosa, Cipangopaludina cathayensis in Zhejiang Province, which in order to supply theoretic basis for the nutrient research of mussels, production of feed and development of novel food. The results showed that water content, ash, crude protein, crude fat and in Bellamya aeruginosai and Cipangopaludina cathayensis were similar, but the content of carbohydrates were different. However, significant differences in ash, crude fat and carbohydrates between Corbicula fluminea and Bellamya aeruginosa, Cipangopaludina cathayensis were observed. There were 18 common amino acids in 3 freshwater mussels, of which 8 were essential amino acids, and the first limiting amino acid was Val and the second limiting amino acid was Ile. Moreover, the content of Glu was the highest among 18 amino acids in

  17. Microplastics in Taihu Lake, China.

    Science.gov (United States)

    Su, Lei; Xue, Yingang; Li, Lingyun; Yang, Dongqi; Kolandhasamy, Prabhu; Li, Daoji; Shi, Huahong

    2016-09-01

    In comparison with marine environments, the occurrence of microplastics in freshwater environments is less understood. In the present study, we investigated microplastic pollution levels during 2015 in Taihu Lake, the third largest Chinese lake located in one of the most developed areas of China. The abundance of microplastics reached 0.01 × 10(6)-6.8 × 10(6) items/km(2) in plankton net samples, 3.4-25.8 items/L in surface water, 11.0-234.6 items/kg dw in sediments and 0.2-12.5 items/g ww in Asian clams (Corbicula fluminea). The average abundance of microplastics was the highest in plankton net samples from the southeast area of the lake and in the sediments from the northwest area of the lake. The northwest area of the lake was the most heavily contaminated area of the lake, as indicated by chlorophyll-α and total phosphorus. The microplastics were dominated by fiber, 100-1000 μm in size and cellophane in composition. To our best knowledge, the microplastic levels measured in plankton net samples collected from Taihu Lake were the highest found in freshwater lakes worldwide. The ratio of the microplastics in clams to each sediment sample ranged from 38 to 3810 and was negatively correlated to the microplastic level in sediments. In brief, our results strongly suggest that high levels of microplastics occurred not only in water but also in organisms in Taihu Lake.

  18. Toxicokinetics/toxicodynamics links bioavailability for assessing arsenic uptake and toxicity in three aquaculture species.

    Science.gov (United States)

    Chen, Wei-Yu; Liao, Chung-Min

    2012-11-01

    The purpose of this study was to link toxicokinetics/toxicodynamics (TK/TD) and bioavailability-based metal uptake kinetics to assess arsenic (As) uptake and bioaccumulation in three common farmed species of tilapia (Oreochromis mossambicus), milkfish (Chanos chanos), and freshwater clam (Corbicula fluminea). We developed a mechanistic framework by linking damage assessment model (DAM) and bioavailability-based Michaelis-Menten model for describing TK/TD and As uptake mechanisms. The proposed model was verified with published acute toxicity data. The estimated TK/TD parameters were used to simulate the relationship between bioavailable As uptake and susceptibility probability. The As toxicity was also evaluated based on a constructed elimination-recovery scheme. Absorption rate constants were estimated to be 0.025, 0.016, and 0.175 mL g(-1) h(-1) and As uptake rate constant estimates were 22.875, 63.125, and 788.318 ng g(-1) h(-1) for tilapia, milkfish, and freshwater clam, respectively. Here we showed that a potential trade-off between capacities of As elimination and damage recovery was found among three farmed species. Moreover, the susceptibility probability can also be estimated by the elimination-recovery relations. This study suggested that bioavailability-based uptake kinetics and TK/TD-based DAM could be integrated for assessing metal uptake and toxicity in aquatic organisms. This study is useful to quantitatively assess the complex environmental behavior of metal uptake and implicate to risk assessment of metals in aquaculture systems.

  19. Chemosensitizers of the multixenobiotic resistance in amorphous aggregates (marine snow): etiology of mass killing on the benthos in the Northern Adriatic?

    Science.gov (United States)

    Müller, W E; Riemer, S; Kurelec, B; Smodlaka, N; Puskaric, S; Jagic, B; Müller-Niklas, G; Queric, N V

    1998-12-01

    Periodically appearing amorphous aggregates, `marine snow', are formed in the sea and if settled as mats on the sea bottom cause death of benthic metazoans. Especially those animals are killed which are sessile filter feeders, e.g. sponges, mussels, or Anthozoa. The etiology of the toxic principle(s) is not yet well understood. Gel-like marine snow aggregates occurred in the Northern Adriatic during summer 1997. Samples of these aggregates were collected during the period July to September and the outer as well as the inner zones were analyzed for (i) cell toxicity, and (ii) chemosensitizing activity of the multixenobiotic resistance (MXR) mechanism. Organic extracts were prepared and cell toxicity was determined using mouse lymphoma cells. The experiments revealed that the major activity is seen in the center of the mats of the gel-like aggregates; a growth inhibitory activity of up to 54% (correlated to 5 ml of snow sample) was determined. The same extracts were used to determine the inhibition of the P-glycoprotein (Pgp) extrusion pump which confers the multixenobiotic resistance. The analyses were performed with cells from the sponge Suberites domuncula and with gills from the clam Corbicula fluminea in situ. Both systems have been shown to express the Pgp extrusion pump. The data show that extracts from the outer zone of the gel-like aggregate samples display pronounced inhibitory activity on the MXR extrusion pump and hence act as chemosensitizers by reversing the MXP property. These findings indicate that gel-like aggregates contain compounds in the outer zone, chemosensitizer of the Pgp extrusion pump, which lower the level of protection of metazoan animals towards dissolved compounds in their surrounding milieu, and in the center toxic compounds which are-very likely-even in the absence of chemosensitizers hazardous for the invertebrates.

  20. Mercury bioaccumulation along food webs in temperate aquatic ecosystems colonized by aquatic macrophytes in south western France.

    Science.gov (United States)

    Gentès, Sophie; Maury-Brachet, Régine; Guyoneaud, Rémy; Monperrus, Mathilde; André, Jean-Marc; Davail, Stéphane; Legeay, Alexia

    2013-05-01

    Mercury (Hg) is considered as an important pollutant for aquatic systems as its organic form, methylmercury (MeHg), is easily bioaccumulated and bioamplified along food webs. In various ecosystems, aquatic periphyton associated with macrophyte was identified as an important place for Hg storage and methylation by microorganisms. Our study concerns temperate aquatic ecosystems (South Western France) colonized by invasive macrophytes and characterized by high mercury methylation potentials. This work establishes original data concerning Hg bioaccumulation in organisms (plants, crustaceans, molluscs and fish) from five contrasting ecosystems. For low trophic level species, total Hg (THg) concentrations were low (from 27±2ngTHgg(-1)dw in asiatic clam Corbicula fluminea to 418±114ngTHgg(-1)dw in crayfish Procambarus clarkii). THg concentrations in some carnivorous fish (high trophic level) were close to or exceeded the International Marketing Level (IML) with values ranging from 1049±220ngTHgg(-1)dw in pike perch muscle (Sander lucioperca) to 3910±1307ngTHgg(-1)dw in eel muscle (Anguilla Anguilla). Trophic levels for the individuals were also evaluated through stable isotope analysis, and linked to Hg concentrations of organisms. A significant Hg biomagnification (r(2)= 0.9) was observed in the Aureilhan lake, despite the absence of top predator fish. For this site, Ludwigia sp. periphyton, as an entry point of Hg into food webs, is a serious hypothesis which remains to be confirmed. This study provides a first investigation of Hg transfer in the ecosystems of south western France and allows the assessment of the risk associated with the presence of Hg in aquatic food webs.

  1. Ocorrência do bivalve exótico Mytilopsis leucophaeta (Conrad (Mollusca, Bivalvia, no Brasil Occurrence of exotic bivalve Mytilopsis leucophaeta (Conrad (Mollusca, Bivalvia, in Brazil

    Directory of Open Access Journals (Sweden)

    José R. B. de Souza

    2005-12-01

    Full Text Available O molusco Mytilopsis leucophaeta (Conrad, 1831, natural da América do Norte, foi localizado no litoral de Pernambuco, Brasil, em 2004, trazido provavelmente por água de lastro de navios. Na região, sua distribuição atualmente abrange zonas estuarinas adjacentes ao Porto do Recife. Os organismos foram encontrados restritos à região entre-marés, formando agregados densos com até 176.800 ind./m².The mussel Mytilopsis leucophaeta (Conrad, 1831 is native to North America. It was found at Pernambuco Coast, northeastern Brazil, in 2004, probably brought by ships' ballast water. The distribution of this species has been now spread to estuarial area near Recife Harbour. They showed a clumped distribution with a maximum of 176,800 ind./m² only in the intertidal zone.

  2. Freshwater Clam Extract Ameliorates Triglyceride and Cholesterol Metabolism through the Expression of Genes Involved in Hepatic Lipogenesis and Cholesterol Degradation in Rats

    Directory of Open Access Journals (Sweden)

    Thomas Laurent

    2013-01-01

    Full Text Available The freshwater clam (Corbicula spp. is a popular edible bivalve and has been used as a folk remedy for liver disease in Asia. As a Chinese traditional medicine, it is said that freshwater clam ameliorates alcoholic intoxication and cholestasis. In this study, to estimate the practical benefit of freshwater clam extract (FCE, we compared the effects of FCE and soy protein isolate (SPI on triglyceride and cholesterol metabolism in rats. FCE and SPI lowered serum cholesterol, and FCE tended to reduce serum triglycerides. FCE enhanced fecal sterol excretion and hepatic mRNA levels of CYP7A1 and ABCG5 more substantially than SPI; however, both diets reduced hepatic cholesterol. Both of the diets similarly suppressed liver lipids improved Δ9-desaturated fatty acid profile, and FCE was associated with a reduction in FAS and SCD1 mRNA levels. Hepatic transcriptome analysis revealed that inhibition of lipogenesis-related gene expression may contribute to downregulation of hepatic triglycerides by FCE. FCE would have better potential benefits for preventing metabolic disorders, through greater improvement of metabolism of triglycerides and cholesterol, likely through a mechanism similar to SPI.

  3. Thermal tolerance ranges and climate variability : A comparison between bivalves from differing climates

    NARCIS (Netherlands)

    Compton, Tanya J.; Rijkenberg, Micha J. A.; Drent, Jan; Piersma, Theunis

    2007-01-01

    The climate variability hypothesis proposes that in variable temperate climates poikilothermic animals have wide thermal tolerance windows, whereas in constant tropical climates they have small thermal tolerance windows. In this study we quantified and compared the upper and lower lethal thermal tol

  4. Interactions of a pesticide/heavy metal mixture in marine bivalves: a transcriptomic assessment

    Directory of Open Access Journals (Sweden)

    Boatti Lara

    2011-04-01

    Full Text Available Abstract Background Mixtures of chemicals present in aquatic environments may elicit toxicity due to additive or synergistic effects among the constituents or, vice versa, the adverse outcome may be reduced by antagonistic interactions. Deviations from additivity should be explained either by the perturbations of toxicokinetic parameters and/or chemical toxicodynamics. We addressed this important question in marine mussels exposed subchronically to a binary mixture made of two wide-spread pollutants: the heavy metal nickel and the organic phosphorus pesticide Chlorpyrifos. To this aim, we carried out in tissues of Mytius galloprovincialis (Lam a systems approach based on the evaluation and integration of different disciplines, i.e. high throughput gene expression profiling, functional genomics, stress biomakers and toxicokinetics. Results Cellular and tissue biomarkers, viz. digestive gland lysosomal membrane stability, lysosomal/cytosol volume ratio, neutral lipid content and gill acetylcholinesterase activity were, in general, altered by either the exposure to nickel and Chlorpyrifos. However, their joint action rendered (i an overall decrease of the stress syndrome level, as evaluated through an expert system integrating biomarkers and (ii statistically significant antagonistic deviations from the reference model systems to predict mixture toxicity. While toxicokinetic modeling did not explain mixture interactions, gene expression profiling and further Gene Ontology-based functional genomics analysis provided clues that the decrement of toxicity may arise from the development of specific toxicodynamics. Multivariate statistics of microarray data (238 genes in total, representing about 14% of the whole microarray catalogue showed two separate patterns for the single chemicals: the one belonging to the heavy metal -135 differentially expressed genes (DEGs was characterized by the modulation of transcript levels involved in nucleic acid metabolism, cell proliferation and lipid metabolic processes. Chlorpyrifos exposure (43 DEGs yielded a molecular signature which was biased towards carbohydrate catabolism (indeed, chitin metabolism and developmental processes. The exposure to the mixture (103 DEGs elicited a composite complex profile which encompassed the core properties of the pesticide but also a relevant set of unique features. Finally, the relative mRNA abundance of twelve genes was followed by Q-PCR to either confirm or complement microarray data. These results, in general, were compatible with those from arrays and indeed confirmed the association of the relative abundance of two GM-2 ganglioside activator genes in the development of the hyperlipidosis syndrome observed in digestive gland lysosomes of single chemical exposed mussels. Conclusion The transcriptomic assessment fitted with biological data to indicate the occurrence of different toxicodynamic events and, in general, a decrease of toxicity, driven by the mitigation or even abolition of lysosomal responses. Furthermore, our results emphasized the importance of the application of mechanistic approaches and the power of systems assessment to study toxicological responses in ecologically relevant organisms.

  5. Exposure dose response relationships of the freshwater bivalve Hyridella australis to cadmium spiked sediments

    Energy Technology Data Exchange (ETDEWEB)

    Marasinghe Wadige, Chamani P.M., E-mail: chamani.marasinghe.wadige@canberra.edu.au; Maher, William A.; Taylor, Anne M.; Krikowa, Frank

    2014-07-01

    Highlights: • The exposure–dose–response approach was used to assess cadmium exposure and toxicity. • Accumulated cadmium in H. australis reflected the sediment cadmium exposure. • Spill over of cadmium into the biologically active pool was observed. • Increased cadmium resulted in measurable biological effects. • H. australis has the potential to be a cadmium biomonitor in freshwater environments. - Abstract: To understand how benthic biota may respond to the additive or antagonistic effects of metal mixtures in the environment it is first necessary to examine their responses to the individual metals. In this context, laboratory controlled single metal-spiked sediment toxicity tests are useful to assess this. The exposure–dose–response relationships of Hyridella australis to cadmium-spiked sediments were, therefore, investigated in laboratory microcosms. H. australis was exposed to individual cadmium spiked sediments (<0.05 (control), 4 ± 0.3 (low) and 15 ± 1 (high) μg/g dry mass) for 28 days. Dose was measured as cadmium accumulation in whole soft body and individual tissues at weekly intervals over the exposure period. Dose was further examined as sub-cellular localisation of cadmium in hepatopancreas tissues. The biological responses in terms of enzymatic and cellular biomarkers were measured in hepatopancreas tissues at day 28. H. australis accumulated cadmium from spiked sediments with an 8-fold (low exposure organisms) and 16-fold (high exposure organisms) increase at day 28 compared to control organisms. The accumulated tissue cadmium concentrations reflected the sediment cadmium exposure at day 28. Cadmium accumulation in high exposure organisms was inversely related to the tissue calcium concentrations. Gills of H. australis showed significantly higher cadmium accumulation than the other tissues. Accumulated cadmium in biologically active and biologically detoxified metal pools was not significantly different in cadmium exposed organisms, which suggests that H. australis has some tolerance to cadmium. The metallothionein like protein fraction played an important role in the sequestration and detoxification of cadmium and the amount sequestered in this fraction increased with increased cadmium exposure. The highest percentage of biologically active cadmium was associated with the lysosome + microsome and mitochondrial fractions. Cadmium concentrations in these two fractions of cadmium exposed organisms were significantly higher with respect to controls. Total antioxidant capacity decreased with increased cadmium exposure and tissue dose. Lipid peroxidation increased and lysosomal membrane stability decreased significantly with increased cadmium exposure and tissue dose. Based on exposure–dose–response analysis in this study, H. australis would be a suitable organism for assessing cadmium sediment exposure and toxicity.

  6. Direct and indirect effects of biological factors on extinction risk in fossil bivalves

    OpenAIRE

    Harnik, Paul G.

    2011-01-01

    Biological factors, such as abundance and body size, may contribute directly to extinction risk and indirectly through their influence on other biological characteristics, such as geographic range size. Paleontological data can be used to explicitly test many of these hypothesized relationships, and general patterns revealed through analysis of the fossil record can help refine predictive models of extinction risk developed for extant species. Here, I use structural equation modeling to tease...

  7. Bivalve aquaculture transfers in Atlantic Europe. Part B: Environmental impacts of transfer activities

    NARCIS (Netherlands)

    Brenner, M.; Fraser, D.; Nieuwenhove, van K.; Kamermans, P.

    2014-01-01

    For centuries human populations have moved live shellfish around the world for consumption or aquaculture purposes; being relayed from their area of origin for growout or sale. This is in contrast to the inadvertent anthropogenic spreading of species via e.g. ballast waters. There are inherent risks

  8. Ecology of the Wood-boring Bivalve Martesia striata (Pholadidae) in Indian Waters

    Science.gov (United States)

    Yennawar, P. L.; Thakur, N. L.; Anil, A. C.; Venkat, K.; Wagh, A. B.

    1999-08-01

    Martesia striata (Linnaeus) is one of the dominant wood-boring organisms found in Indian waters. Incidence of this organism in the Zuari estuary (Goa) was evaluated by exposing wooden panels (Mangifera indica) to the marine environment between January 1996 and January 1997. Effects of salinity variation on embryonic and larval development were evaluated (salinity 0, 10, 20, 30, 35, 40 and 50, temperature 25 °C) and maximum metamorphic success was observed at 30 salinity. Results of the rearing experiments, destruction pattern of wood in the environment and reproductive biology indicate that although recruitment is halted during the monsoon, adults survive and become reproductively mature in the following post-monsoon, leading to increased recruitment during pre-monsoon months.

  9. Spatial arrangement of genetic variation in the marine bivalve Macoma balthica (L.)

    NARCIS (Netherlands)

    Luttikhuizen, Pieternella Christina

    2003-01-01

    Phenotypic similarities come in two kinds: those that are partially based on genetic differences and those that are not. Genetic variation is inherently heritable and without it, evolution by means of natural selection could not occur. It is therefore important to understand the origin and maintenan

  10. VIVALDI, A H2020 European Project aiming at preventing and mitigating farmed bivalve diseases

    OpenAIRE

    ARZUL, Isabelle; Feist, Steve; Figueras, Antonio; Lapegue, Sylvie; Paillard, Christine; Furones, Dolors

    2016-01-01

    The European shellfish industry enjoys a privileged position on the global scene. Its social dimension is essential, as it employs a high number of people in more than 8000 companies, mostly micro-companies. Shellfish production in Europe is little diversified and mainly relies on the industrially produced mussels, oysters and clams. Over the recent years, this sector has grown more slowly than other fish farming sectors, notably because it depends a great deal on the environmental quality...

  11. A redox proteomic investigation of oxidative stress caused by benzoylecgonine in the freshwater bivalve Dreissena polymorpha.

    Science.gov (United States)

    Pedriali, Alessandra; Riva, Consuelo; Parolini, Marco; Cristoni, Simone; Sheehan, David; Binelli, Andrea

    2013-08-01

    Drugs of abuse and their human metabolites have been recently recognized as emerging environmental contaminants. Notwithstanding the fact that these kinds of compounds share some features with pharmaceuticals, their ecotoxicology has not yet been extensively investigated, although some of their characteristics may potentially threaten aquatic ecosystems. One of the most abundant drugs found in rivers and wastewaters is benzoylecgonine (BE), the main metabolite of cocaine. We applied a redox proteomics approach to evaluate changes in the proteome of Dreissena polymorpha exposed to two different concentrations of BE (0.5 and 1 µg/l). Exposures were performed in vivo for a period of 14 days and the effect of oxidative stress on protein thiol and carbonyl groups in mussel gills were evaluated. One-dimensional electrophoresis did not reveal a reduction in protein thiol content but showed a significant increase of protein carbonylation at both doses tested. Then, protein profiling using two-dimensional gel electrophoresis was performed with subsequent matrix assisted laser desorption/ionization time-of-flight (MALDI-TOF) and TOF/TOF with LIFT technique and linear ion trap combined with orbitrap mass spectrometer (LTQ-Orbitrap). This yielded de novo protein sequences suitable for database searching. These preliminary results and protein identifications obtained suggest that BE causes oxidative stress. Oxidative modifications were detected in differing classes of proteins such as those of the cytoskeleton, energetic metabolism and stress response.

  12. Indirect effects of non-lethal predation on bivalve activity and sediment reworking

    NARCIS (Netherlands)

    Maire, O.; Merchant, J.N.; Bulling, M.; Teal, L.R.; Gremare, A.; Duchene, J.C.; Solan, M.

    2010-01-01

    Deposit-feeders are the dominant bioturbators of aquatic sediments, where they profoundly impact biogeochemical processes, but they are also vulnerable to both lethal and non-lethal predation by a large variety of predators. In this study, we performed a series of experiments to test the effects of

  13. Bivalve aquaculture transfers in Atlantic Europe. Part B: Environmental impacts of transfer activities

    DEFF Research Database (Denmark)

    Brenner, M.; Fraser, D.; Van Nieuwenhove, K.

    2014-01-01

    For centuries human populations have moved live shellfish around the world for consumption or aquaculture purposes; being relayed from their area of origin for growout or sale. This is in contrast to the inadvertent anthropogenic spreading of species via e.g. ballast waters. There are inherent ri...

  14. Macrophyte canopy structure and the success of an invasive marine bivalve

    NARCIS (Netherlands)

    Reusch, TBH; Williams, SL

    1999-01-01

    In both terrestrial and aquatic environments introductions of non-indigenous species are continuing and represent one important component of global change. Negative biotic interactions by resident species may prevent successful invaders from becoming pests. Few experimental data are available on the

  15. Significant genetic differentiation among populations of Anomalocardia brasiliana (Gmelin, 1791): A bivalve with planktonic larval dispersion

    Science.gov (United States)

    2009-01-01

    Four Brazilian populations of Anomalocardia brasiliana were tested for mutual genetic homogeneity, using data from 123 sequences of the mtDNA cytochrome oxidase c subunit I gene. A total of 36 haplotypes were identified, those shared being H3 (Canela Island, Prainha and Acupe) and both H5 and H9 (Prainha and Acupe). Haplotype diversity values were high, except for the Camurupim population, whereas nucleotide values were low in all the populations, except for that of Acupe. Only the Prainha population showed a deviation from neutrality and the SSD test did not reject the demographic expansion hypothesis. Fst values showed that the Prainha and Acupe populations represent a single stock, whereas in both the Canela Island and Camurupim stocks, population structures are different and independent. The observed structure at Canela Island may be due to the geographic distance between this population and the remainder. The Camurupim population does not share any haplotype with the remaining populations in northeastern Brazil. The apparent isolation could be due to the rocky barrier located facing the mouth of the Mamanguape River. The results highlight the importance of wide-scale studies to identify and conserve local genetic diversity, especially where migration is restricted. PMID:21637701

  16. Morphology and taxonomy of Isognomon spathulatus (Reeve, 1858), a cryptic bivalve from the mangroves of Thailand.

    Science.gov (United States)

    Tëmkin, Ilya; Printrakoon, Cheewarat

    2016-01-01

    Isognomon spathulatus (Reeve, 1858) is redescribed based on type material and original collections from Kungkrabaen Bay, Thailand. The species agrees with previously described isognomonids in most conchological and anatomical features, but possesses a suite of diagnostic characters, including a comma-shaped outline of the nacreous border, an uncoiled ventral diverticulum of the stomach, and the thickened mantle lobes with granulated cells. This study is the most comprehensive morphological analysis to date for any species of Isognomonidae Woodring, 1925 (1828). It describes and illustrates a number of previously unrecognized or underutilized anatomical characters of potential phylogenetic significance: the morphology of the byssal threads (cross-sectional shape, plumate rootlets, and the shape of adhesive disks), the presence and extent of the interdemibranchial buttresses, the presence of secretory cells in the central zone of the mantle, the shape of the ventral diverticulum of the gastric chamber, the presence of the typhlosolar guard ridge, and the position of the renal pore. A comparison is made between I. spathulatus and morphologically similar Isognomon ephippium (Linnaeus, 1758) with which it has been previously synonymized. Pearls of both species are described and illustrated. Individuals of I. spathulatus inhabit mangroves, where they attach by byssus to prop roots, typically in parapatry with individuals of I. ephippium that occupy adjacent mudflats. The spacial distribution and diverging adaptive strategies (pertaining to physical stabilization and response to predation) displayed by the two isognomonid species are considered in the light of the ecological speciation theory.

  17. Radiostrontium monitoring of bivalves from the Pacific coast of eastern Japan.

    Science.gov (United States)

    Karube, Zin'ichi; Inuzuka, Yoko; Tanaka, Atsushi; Kurishima, Katsuaki; Kihou, Nobuharu; Shibata, Yasuyuki

    2016-09-01

    In early April 2011, radiostrontium was accidentally released from the Fukushima Daiichi Nuclear Power Plant to the Pacific coast of eastern Japan. We developed a simple procedure to analyze radiostrontium levels in marine mussels (Septifer virgatus) and seawater using crown ether (Sr Resin; Eichrom). Then, we used our method to describe the spatial and temporal distribution of radiostrontium in mussels and seawater on the Pacific coast of eastern Japan from 2011 to 2013 and for 2015. Activity of (90)Sr in mussels and seawater decreased with distance from the Fukushima Daiichi Nuclear Power Plant and between 2011 and 2013 tended to be higher in areas south of the Fukushima Daiichi Nuclear Power Plant than to the north of it. Activity in mussels and seawater also tended to decrease from 2011 to 2013 and by 2015 had reached levels experienced prior to the Fukushima accident. Our results suggest that radiostrontium discharged from the Fukushima Daiichi Nuclear Power Plant was dispersed by coastal currents in a southerly direction along the Pacific coast of eastern Japan from 2011 to 2013, following which its activity decreased to background levels by 2015.

  18. Reproduction involving spermatophores in four bivalve genera of the superfamily Galeommatoidea commensal with holothurians

    DEFF Research Database (Denmark)

    Lützen, Jørgen; Kato, Makoto; Kosuge, Takeharu

    2005-01-01

    Spermatophores consisting of a mass of mature sperm encapsulated within a solid, inflexible wall are described from five species of the genera Anisodevonia, Entovalva and Devonia, and obviously also occur in Cycladoconcha. The spermatophores are attached to the gill lamellae in the suprabranchial...

  19. Effets du chlorure de cadmium et du chromate de plomb sur deux mollusques bivalves

    OpenAIRE

    Ballan-dufrancais, C.; Jeantet, A.y.; Martoja, R; Truchet, M

    1985-01-01

    La contamination expérimentale d'huîtres par le chlorure de cadmium (500 µg/1 pendant 7 et 26 jours) ne cause aucune lésion histologique ou cytologique, mais elle accélère la déplétion testiculaire et, dans quelques cas, s'oppose au stockage du glycogène. L'excellente résistance des huîtres est due à l'efficacité de deux types de mécanismes de détoxication. Le premier consiste en une immobilisation du cadmium, dans les organes absorbants, dans un état chimique stable et inerte sur le plan mét...

  20. Sulfur contents and sulfur-isotope compositions of thiotrophic symbioses in bivalve molluscs and vestimentiferan worms

    Science.gov (United States)

    Vetter, R.D.; Fry, B.

    1998-01-01

    Total sulfur (S(TOT)), elemental sulfur (S??) and sulfur-isotope compositions (??34S) of marine animals were analyzed to determine whether these chemical characteristics could help distinguish animals with a sulfur-based, thiotrophic nutrition from animals whose nutrition is based on methanotrophy or on more normal consumption of phytoplankton-derived organic matter. The presence of S??was almost entirely confined to the symbiont-containing tissues of thiotrophs, but was sometimes undetectable in thiotrophic species where sulfide availability was probably low. When S??contents were subtracted, the remaining tissue-sulfur concentrations were similar for all nutritional groups. ??34S values were typically lower for thiotrophs than for other groups, although there was overlap in methanotroph and thiotroph values at some sites. Field evidence supported the existence of small to moderate (1 to 10???)34S fractionations in the uptake of sulfides and metabolism of thiosulfate. In general, a total sulfur content of >3% dry weight, the presence of elemental sulfur, and ??34S values less than + 5??? can be used to infer a thiotrophic mode of nutrition.

  1. Site-specific distribution of the bivalve Scrobicularia plana along the European coast

    NARCIS (Netherlands)

    Santos, Silvia; Aarts, Geert; Luttikhuizen, Pieternella C.; Campos, Joana; Piersma, Theunis; van der Veer, Henk W.; Hughes, Roger

    2012-01-01

    The development and maintenance of spatial patterns and the way they affect the dynamics of populations and ecosystems is a key issue in ecology. Since each individual and each species experiences the environment on a unique range of scales, it is vital to determine the spatial scales across which o

  2. Conditional Responses of Benthic Communities to Interference from an Intertidal Bivalve.

    Directory of Open Access Journals (Sweden)

    Carl Van Colen

    Full Text Available Habitat-modifying organisms that impact other organisms and local functioning are important in determining ecosystem resilience. However, it is often unclear how the outcome of interactions performed by key species varies depending on the spatial and temporal disturbance context which makes the prediction of disturbance-driven regime shifts difficult. We investigated the strength and generality of effects of the filter feeding cockle Cerastoderma edule on its ambient intertidal benthic physical and biological environment. By comparing the magnitude of the effect of experimental cockle removal between a non-cohesive and a sheltered cohesive sediment in two different periods of the year, we show that the outcome of cockle interference effects relates to differences in physical disturbance, and to temporal changes in suspended sediment load and ontogenetic changes in organism traits. Interference effects were only present in the cohesive sediments, though the effects varied seasonally. Cockle presence decreased only the density of surface-dwelling species suggesting that interference effects were particularly mediated by bioturbation of the surface sediments. Furthermore, density reductions in the presence of cockles were most pronounced during the season when larvae and juveniles were present, suggesting that these life history stages are most vulnerable to interference competition. We further illustrate that cockles may enhance benthic microalgal biomass, most likely through the reduction of surface-dwelling grazing species, especially in periods with high sediment load and supposedly also high bioturbation rates. Our results emphasize that the physical disturbance of the sediment may obliterate biotic interactions, and that temporal changes in environmental stressors, such as suspended sediments, may affect the outcome of key species interference effects at the local scale. Consequently, natural processes and anthropogenic activities that change bed shear stress and sediment dynamics in coastal soft-sediment systems will affect cockle-mediated influences on ecosystem properties and therefore the resilience of these systems to environmental change.

  3. Genetic traits in the bivalve Mytilus from Europe, with an emphasis on Arctic populations

    NARCIS (Netherlands)

    Hummel, H.; Colucci, P.; Bogaards, R.H.; Strelkov, P.P.

    2001-01-01

    Genetic and some ecophysiological traits of mussels collected in the European Arctic, up to their northeastern distribution limit in the Barents Sea, were studied and compared with traits of mussels from the Mediterranean, Atlantic and Baltic. The genetic traits of these populations we-re analysed b

  4. Biomonitoring of mercury pollution in a wetland near Ravenna, Italy by translocated bivalves (Mytilus galloprovincialis)

    Energy Technology Data Exchange (ETDEWEB)

    Cattani, O.; Fabbri, D.; Salvati, M.; Trombini, C.; Vassura, I.

    1999-08-01

    An active biomonitoring experiment using mussels (Mytilus galloprovincialis) was performed in Pialassa Baiona, a mercury-polluted coastal wetland near Ravenna, Italy. Three stations (A, B, and C) were selected along the south to north axis. Following a 52-d field exposure, organisms transplanted in the southernmost polluted area (station A) showed mean mercury concentration values of 660 ng/g (dry weight), 4.4 times the initial background level, and were still accumulating mercury. Mussels in both the central area (station B) and the northern area (station C) seemed to reach a steady state with mean mercury concentration values of 323 and 412 ng/g, respectively. This field experiment is the first study carried out in the Ravenna wetlands to evaluate mercury bioavailability in this environment. Finally, the efficiency of the population of Mytilus galloprovincialis selected for the field experiment as mercury bioaccumulators was tested in a laboratory experiment that revealed that up to 135 {micro}g/g (dry weight) could be reached after 77 d of exposure to mercury-polluted water.

  5. Ecology of the wood-boring bivalve Martesia striata (Pholadidae) in Indian waters

    Digital Repository Service at National Institute of Oceanography (India)

    Yennawar, P.L.; Thakur, N.L.; Anil, A.C.; Venkat, K.; Wagh, A.B.

    Martesia striata is one of the dominant wood-boring organisms found in Indian waters. Incidence of this organism in the Zuari estuary (Goa) was evaluated by exposing wooden panels (Mangifera indica) to the marine environment between January 1996...

  6. Temporal and spatial variations in iron concentrations of tropical bivalves during dredging event

    Digital Repository Service at National Institute of Oceanography (India)

    Brown, B.E.; Jayakumar, A.

    JEAN-CLAUDE DAUVIN and FRANCK GENTIL C.N.R.S. UPR 4601 and UniversitO P.&M. Curie, Station Biologique, 29682 Roscoff, France Peracarid populations were greatly reduced in 1978 by oil from the Amoco Cadiz. Ten years after the spill, a benthic survey...

  7. Detection and quantification of Sapovirus in bivalve molluscs from Galicia (NW Spain.

    Directory of Open Access Journals (Sweden)

    Jesus L Romalde

    2014-06-01

    SaV was detected in 30 of the 168 samples (17,85%. There was no significant difference between the two Rías in terms of detections, although it was observed a seasonality increment of positive samples from November 2011 until April 2012 in both Rías due to the rainy season and the decrease of seawater temperature. Total quantification ranged between 103 and 105 copies of viral RNA/g of digestive tissue (c/g, being mussels the specie with lower main quantification (3,1 x 104 c/g and clams the species with higher medium rates (2,0 x 105 c/g. This represents the first study out of Japan in which human Sapovirus was detected and quantified into human food intended for consumption.

  8. Spatial distribution modelling of the endangered bivalve Pinna nobilis in a Marine Protected Area

    Directory of Open Access Journals (Sweden)

    M. VÁZQUEZ-LUIS

    2014-09-01

    Full Text Available The spatial distribution of Pinna nobilis densities have been analysed through a geostatistical approach in the MPA of Cabrera National Park, Balearic Islands (Spain, Western Mediterranean Sea. Regression kriging was used to model the effect of environmental variables on the density of living individuals of P. nobilis and generate a predictive map of its distribution within the MPA. The environmental variables considered for the model were: depth; slope; habitat type and heterogeneity; wave exposure; and MPA zoning. A total of 378 transects were randomly distributed with a total of 149,000 m2 surveyed at a depth range from 4.2 to 46 m. The recorded P. nobilis densities are among the highest in the Mediterranean Sea. With respect to the prediction model, results indicate that benthic habitats play a key role in the spatial distribution of P. nobilis, with higher densities in seagrass meadows of Posidonia oceanica. The fan mussel population density peaked at 9 m depth, decreasing with depth. Also, decreasing densities are expected with increasing exposure to waves. The predicted map shows some hotspots of density different in size and distributed along the MPA, and provides valuable information for the spatial conservation management of this species.

  9. Relative infaunal bivalve density assessed from split beam echosounder angular information

    Directory of Open Access Journals (Sweden)

    Noela Sánchez-Carnero

    2014-06-01

    Full Text Available Management of shellfish resources requires a spatial approach where mapping is a key tool. Acoustic techniques have been rarely used to map infaunal organisms with a patchy distribution. We propose and test the use of split-beam echosounder angular information to assess razor shell presence and relative density. Our statistical approach combines textural analysis of angular echograms, standard unsupervised multivariate methods and hierarchical classification through dendrograms to identify groups of locations with similar clam densities. The statistical analyses show that the classification is consistent with groundtruthing data and that results are insensitive to boat motion or seabed granulometry. The method developed here constitutes a promising tool for assessing the relative density of razor clam grounds.

  10. Biophysical constraints on optimal patch lengths for settlement of a reef-building bivalve.

    Directory of Open Access Journals (Sweden)

    Heidi L Fuchs

    Full Text Available Reef-building species form discrete patches atop soft sediments, and reef restoration often involves depositing solid material as a substrate for larval settlement and growth. There have been few theoretical efforts to optimize the physical characteristics of a restored reef patch to achieve high recruitment rates. The delivery of competent larvae to a reef patch is influenced by larval behavior and by physical habitat characteristics such as substrate roughness, patch length, current speed, and water depth. We used a spatial model, the "hitting-distance" model, to identify habitat characteristics that will jointly maximize both the settlement probability and the density of recruits on an oyster reef (Crassostrea virginica. Modeled larval behaviors were based on laboratory observations and included turbulence-induced diving, turbulence-induced passive sinking, and neutral buoyancy. Profiles of currents and turbulence were based on velocity profiles measured in coastal Virginia over four different substrates: natural oyster reefs, mud, and deposited oyster and whelk shell. Settlement probabilities were higher on larger patches, whereas average settler densities were higher on smaller patches. Larvae settled most successfully and had the smallest optimal patch length when diving over rough substrates in shallow water. Water depth was the greatest source of variability, followed by larval behavior, substrate roughness, and tidal current speed. This result suggests that the best way to maximize settlement on restored reefs is to construct patches of optimal length for the water depth, whereas substrate type is less important than expected. Although physical patch characteristics are easy to measure, uncertainty about larval behavior remains an obstacle for predicting settlement patterns. The mechanistic approach presented here could be combined with a spatially explicit metapopulation model to optimize the arrangement of reef patches in an estuary or region for greater sustainability of restored habitats.

  11. New insights from the oyster Crassostrea rhizophorae on bivalve circulating hemocytes.

    Directory of Open Access Journals (Sweden)

    Mauro de Freitas Rebelo

    Full Text Available Hemocytes are the first line of defense of the immune system in invertebrates, but despite their important role and enormous potential for the study of gene-environment relationships, research has been impeded by a lack of consensus on their classification. Here we used flow cytometry combined with histological procedures, histochemical reactions and transmission electron microscopy to characterize the hemocytes from the oyster Crassostrea rhizophorae. Transmission electron microscopy revealed remarkable morphological characteristics, such as the presence of membranous cisternae in all mature cells, regardless of size and granulation. Some granular cells contained many cytoplasmic granules that communicated with each other through a network of channels, a feature never previously described for hemocytes. The positive reactions for esterase and acid phosphatase also indicated the presence of mature cells of all sizes and granule contents. Flow cytometry revealed a clear separation in complexity between agranular and granular populations, which could not be differentiated by size, with cells ranging from 2.5 to 25 µm. Based on this evidence we suggest that, at least in C. rhizophorae, the different subpopulations of hemocytes may in reality be different stages of one type of cell, which accumulates granules and loses complexity (with no reduction in size as it degranulates in the event of an environmental challenge.

  12. Intraspecific egg size variation and sperm limitation in the broadcast spawning bivalve

    NARCIS (Netherlands)

    Luttikhuizen, P.C.; Honkoop, P.J.C.; Drent, J.

    2011-01-01

    Broadcast spawners are exceptionally suited and simple models for studying parental investment in offspring, because direct post-spawning investment is nonexistent. However, a comprehensive understanding of the large variation that exists in their egg sizes is still lacking. One of the main hypothes

  13. Fossil Cenozoic crassatelline bivalves from Peru: New species and generic insights

    Directory of Open Access Journals (Sweden)

    Thomas J. DeVries

    2016-08-01

    Full Text Available Discoveries of new fossil Cenozoic crassatellines in Peru provide a new phylogenetic perspective on “large” Neogene genera, in which four lineages are considered to have arisen independently from different Paleogene Crassatella ancestors. Latest Oligocene and early Miocene species of the new genus Tilicrassatella gen. nov.―T. ponderosa, T. torrens sp. nov., and T. sanmartini sp. nov. from the East Pisco Basin―probably evolved from the late Eocene species, Crassatella rafaeli sp. nov., which itself differed in significant respects from slightly older species of the East Pisco Basin, C. neorhynchus and C. pedroi sp. nov. The paciphilic genus, Hybolophus, is raised to full generic status. Added to its ranks are the East Pisco Miocene species H. maleficae sp. nov., H. terrestris sp. nov., and the oldest species of the genus, the late Eocene or Oligocene H. disenum sp. nov. from the Talara Basin of northern Peru. Kalolophus gen. nov., encompassing circum-Caribbean fossil species, the extant species, K. speciosus, and the trans-isthmus species, K. antillarum, appears to have evolved from the early Oligocene Floridian species, Crassatella portelli sp. nov. The genus Marvacrassatella is a western Atlantic Miocene lineage most likely descended from Kalolophus. The genus Eucrassatella is restricted to Australian and New Zealand taxa. The Eocene New Zealand species, Spissatella media, is transferred to Eucrassatella and deemed a candidate for the most recent common ancestor of younger Eucrassatella and all Spissatella species. In the southern Pacific Ocean, the circum-Caribbean region, and tropical western America, crassatelline lineages developed one or more of the following characters: large resilifers, smooth ventral margins, and an extended left anterior cardinal tooth. Some of these late Paleogene convergent character changes might have countered increased shear forces exerted on the crassatelline valves while burrowing into finer-grained and more cohesive sediments in deeper or quieter water.

  14. Structure of sperm, spermatozeugmata and 'lateral organs' in the bivalve Arthritica (Galeommatoidea: Leptonidae)

    DEFF Research Database (Denmark)

    Jespersen, Åse; Lützen, Jørgen

    2009-01-01

    The position and structure of paired 'lateral organs' in the foot of Arthritica semen and Arthritica bifurca might indicate a chemosensory function. In both species part of the organ is also glandular. In A. semen the glandular epithelium is detached piecemeal and, probably by means of the foot......, is moved to and grafted upon the gills of the same individual. The transferred epithelia appear as disk-shaped actively secretory 'gill bodies' which, attached to the abfrontal side of the inner demibranch, replace the ordinary unciliated gill epithelium. The secretion is liberated into the suprabranchial...

  15. Bioaccumulation of microcystins in invasive bivalves: A case study from the boreal lagoon ecosystem

    Directory of Open Access Journals (Sweden)

    Aistė Paldavičienė

    2015-01-01

    Full Text Available In the current study we present the first report on the bioaccumulation of microcystins (MC in zebra mussel Dreissena polymorpha from the eutrophic brackish water Curonian Lagoon. The bioaccumulation capacity was related to age structure of mussels and ambient environmental conditions. We also discuss the relevant implications of these findings for biomonitoring of toxic cyanobacteria blooms in the Curonian Lagoon and potential consequences for D. polymorpha cultivation activities considered for the futures as remediation measure. Samples for the analysis were collected twice per year, in June and September, in 2006, 2007 and 2008, from two sites within the littoral zone of the lagoon. The highest microcystin concentrations were measured in mussels larger than 30 mm length and sampled in 2006 (when a severe toxic cyanobacteria bloom occurred. In the following years, a consistent reduction in bioaccumulated MC concentration was noticed. However, certain amount of microcystin was recorded in mussel tissues in 2007 and 2008, when no cyanotoxins were reported in the phytoplankton. Considering high depuration rates and presence of cyanotoxins in the bottom sediments well after the recorded toxic blooms, we assume mechanism of secondary contamination when microcystin residuals could be uptaken by mussels with resuspended sediment particles.

  16. Identification of lysozyme activity from two edible bivalves - Perna viridis (Linnaeus) and Meretrix casta (Chemnitz)

    Digital Repository Service at National Institute of Oceanography (India)

    Sharma, S.; Tanu; Chatterji, A.

    with the pathogen Vibrio tapetis. J. Invertebr. Pathol., 76, 63–69. Bachali, S., Jager, M., Hassanin, A., Schoentgen, F., Jolles, P., Fiala-Medioni, A. and Deutsch, J.S. (2002). Phylogenetic analysis of invertebrate lysozymes and the evolution of lysozyme... function. J. Mol. Evol., 54, 652–664. Bachali, S., Bailly, X., Jolles, J., Jolles, P. and Deutsch, J.S. (2004). The lysozyme of the starfish Asterias rubens. A paradygmatic type i lysozyme. Eur. J. Biochem., 271, 237-242. Chipman, D.M. and Sharon, N...

  17. Comparative in vitro study on free radical scavenging potential of selected bivalve species

    Digital Repository Service at National Institute of Oceanography (India)

    Shenai-Tirodkar, P.S.; Pawar, R.T.; Jagtap, T.G.

    , DNA and carbohydrates leading to number of diseases especially cancer, aging, arthritis, inflammation, diabetes, parkinson’s disease and atherosclerosis (4, 5). In addition, radical-mediated lipid peroxidation negatively impacts flavour, texture...

  18. Metals and organotins in multiple bivalve species in a one-off global survey

    DEFF Research Database (Denmark)

    Larsen, Martin Mørk; Strand, Jakob; Christensen, Jan H.;

    2011-01-01

    concentrations (BACs) agreed in the Oslo-Paris convention (OSPAR) for the North Sea, and at most harbours the concentrations were orders of magnitude above BACs. The lowest concentrations of Cd and Pb measured here suggest that the BACs should be lower in a worldwide context. The sources of metals were...

  19. Phenoloxidase activity in larval and juvenile homogenates and adult plasma and haemocytes of bivalve molluscs.

    Science.gov (United States)

    Luna-González, Antonio; Maeda-Martínez, Alfonso N; Vargas-Albores, Francisco; Ascencio-Valle, Felipe; Robles-Mungaray, Miguel

    2003-10-01

    Phenoloxidase (PO) activity was studied in larval and juvenile homogenates and in the plasma and haemocytes of adult Crassostrea gigas, Argopecten ventricosus, Nodipecten subnodosus, and Atrina maura. Samples were tested for the presence of PO activity by incubation with the substrate L-3, 4-dihydroxyphenylalanine using trypsin, alpha-chymotrypsin, laminarin, lipopolysaccharides (LPS), and sodium dodecyl sulphate (SDS) to elicit activation of prophenoloxidase (proPO) system. PO activity was not detected in larval homogenate. In juvenile homogenate, PO activity was found only in C. gigas and N. subnodosus. PO activity was present in adult samples and was enhanced by elicitors in the plasma of all species tested, but in haemocyte lysate supernatant (HLS) of only N. subnodosus. Activation of proPO by laminarin was suppressed by a protease inhibitor cocktail (P-2714) in plasma and HLS of all species tested.

  20. Accumulation, elimination and chemical speciation of mercury in the bivalves Mytilus edulis and Macoma balthica

    DEFF Research Database (Denmark)

    Riisgård, H. U.; Kiørboe, Thomas; Møhlenberg, F.;

    1985-01-01

    Mussels (Mytilus edulis) transferred in net bags from clean to chronically mercury polluted water readily accumulated mercury during an exposure period of three months. Growth of the transplanted mussels had a “diluting” effect on the mercury concentration, but the absolute weight of mercury uptake...... increased throughout the entire period, though there was a tendency for decreased efficiency of the removal of mercury per liter of water filtered by the mussels. Mussels were also translocated from polluted to clean (laboratory) water to depurate mercury. The biological half-lives of mercury was 293 d...... for M. edulis from the chronically polluted area in contrast to only 53 d for mussels from a temporary massive mercury polluted area near a chemical deposit. In both cases about 75% of the total mercury in the mussels was inorganic, and it is suggested that both inorganic and organic mercury species...