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Sample records for bivalve codakia orbicularis

  1. Megalocytivirus infection in orbiculate batfish Platax orbicularis.

    Science.gov (United States)

    Sriwanayos, Preeyanan; Francis-Floyd, Ruth; Stidworthy, Mark F; Petty, Barbara D; Kelley, Karen; Waltzek, Thomas B

    2013-07-01

    Megalocytiviruses cause systemic disease in both marine and freshwater fishes, negatively impacting ornamental and food fish aquaculture. In this report, we characterize a megalocytivirus infection in a captive marine ornamental fish, the orbiculate batfish Platax orbicularis. Histologic examination revealed cytomegalic cells characterized by strongly basophilic granular intracytoplasmic inclusions within various organs. Transmission electron microscopy revealed icosahedral virus particles within the cytoplasm of cytomegalic cells consistent with an iridovirus infection. Analysis of the major capsid protein gene sequence confirmed that the orbiculate batfish virus is a member of the family Iridoviridae and is identical to the only other megalocytivirus reported from a marine ornamental fish, the Banggai cardinalfish Pterapogon kauderni iridovirus. PMID:23836765

  2. La synchronisation des pontes chez Platax orbicularis

    OpenAIRE

    Boichard, Sylvestre

    2008-01-01

    Le contrôle des pontes est primordial en aquaculture pour démarrer une filière pérenne. Il permet en premier lieu de ne plus dépendre des pontes naturelles dont les conditions de déclenchement sont mal connues pour la plupart des espèces. Le risque de se trouver, même pendant un temps relativement court, sans aucune production d’œufs peut mettre en danger la totalité de la filière. Pour Platax orbicularis (Paraha peue en polynésien) il a été intéressant de comparer deux méthodes d’inductio...

  3. The minimally invasive, orbicularis-sparing, lower eyelid recession for mild to moderate lower eyelid retraction with reduced orbicularis strength.

    Science.gov (United States)

    Yoo, Donald B; Griffin, Garrett R; Azizzadeh, Babak; Massry, Guy G

    2014-01-01

    IMPORTANCE Identifying a procedure to address lower eyelid retraction (LER) in the presence of an orbicularis deficit is a useful tool for aesthetic and reconstructive eyelid surgery. OBJECTIVE To describe and evaluate a surgical technique consisting of a closed canthal suspension and true lower eyelid retractor recession to address LER in the setting of orbicularis weakness. DESIGN, SETTING, AND PARTICIPANTS A retrospective medical record review of patients who underwent the minimally invasive, orbicularis-sparing, lower eyelid recession from January 1, 2010, to October 1, 2012, by one of us (G.G.M.) in an ophthalmic plastic surgical practice. We included 29 patients with reduced orbicularis strength and LER resulting from eyelid paresis related to facial nerve disease, surgical trauma (after blepharoplasty), involutional change, or idiopathic causes. INTERVENTIONS Surgical intervention consisting of closed canthal suspension and lower eyelid retractor recession. MAIN OUTCOMES AND MEASURES Surgical results, complications, and patient satisfaction. RESULTS The 29 patients included 18 women and 11 men. The mean patient age was 52 (range, 6-72) years; mean follow-up, 11 (range, 6-21) months; and mean preoperative orbicularis strength, 2.7 (on a scale of 0-4, where 0 indicates no function and 4, normal function). The causes of orbicularis weakness included eyelid paresis related to facial nerve disease (11 patients), surgical trauma (13 patients), involutional change (4 patients), and an isolated idiopathic finding (1 patient). In 12 patients, the eyelid retraction was unilateral; in 17, bilateral. A small tarsorrhaphy was added to the surgery in 6 patients with facial nerve disease. The mean eyelid elevation after surgery was 1.80 mm, with only minor complications. Patient and surgeon satisfaction were high. CONCLUSIONS AND RELEVANCE Recent publications have demonstrated the utility of closed canthal suspension and true lower eyelid retractor recession as separate

  4. Plasticity of symbiont acquisition throughout the life cycle of the shallow-water tropical lucinid Codakia orbiculata (Mollusca: Bivalvia).

    Science.gov (United States)

    Gros, Olivier; Elisabeth, Nathalie H; Gustave, Sylvie D D; Caro, Audrey; Dubilier, Nicole

    2012-06-01

    In marine invertebrates that acquire their symbionts from the environment, these are generally only taken up during early developmental stages. In the symbiosis between lucinid clams and their intracellular sulfur-oxidizing bacteria, it has been shown that the juveniles acquire their symbionts from an environmental stock of free-living symbiont forms, but it is not known if adult clams are still competent to take up symbiotic bacteria from the environment. In this study, we investigated symbiont acquisition in adult specimens of the lucinid clam Codakia orbiculata, using transmission electron microscopy, fluorescence in situ hybridization, immunohistochemistry and PCR. We show here that adults that had no detectable symbionts after starvation in aquaria for 6 months, rapidly reacquired symbionts within days after being returned to their natural environments in the field. Control specimens that were starved and then exposed to seawater aquaria with sulfide did not reacquire symbionts. This indicates that the reacquisition of symbionts in the starved clams returned to the field was not caused by high division rates of a small pool of remaining symbionts that we were not able to detect with the methods used here. Immunohistochemistry with an antibody against actin, a protein involved in the phagocytosis of intracellular bacteria, showed that actin was expressed at the apical ends of the gill cells that took up symbionts, providing further evidence that the symbionts were acquired from the environment. Interestingly, actin expression was also observed in symbiont-containing cells of untreated lucinids freshly collected from the environment, indicating that symbiont acquisition from the environment occurs continuously in these clams throughout their lifetime. PMID:22672589

  5. Orbicularis oris musculomucosal flap for anterior palatal fistula

    Directory of Open Access Journals (Sweden)

    Tiwari V

    2006-01-01

    Full Text Available Anterior palatal fistulae or residual anterior clefts are a frequent problem following palatoplasty. Various techniques have been used to repair such fistulae, each having its own advantages and disadvantages. We have successfully used orbicularis oris musculomucosal flap to close anterior fistula and residual clefts in 25 patients. This study shows the superiority of this flap over other techniques because of its reliable blood supply, easy elevation and transfer to fistula site and finally because it is a single-stage procedure.

  6. Overwintered Hatchlings of Emys orbicularis from Lake Sülüklü (Western Anatolia, Turkey

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    Dinçer Ayaz

    2011-07-01

    Full Text Available During our monitoring survey of amphibians and Emys orbicularis in Lake Sülüklü (Western Anatolia, Turkey, we observed four overwintered hatchlings of European pond turtle on May 4 and 10, 2010. The average straightline maximum carapace length of the neonates captured was 26.48 mm and their average weight was 4.18 g. This observation is the second record for the Turkish population of Emys orbicularis.

  7. 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

  8. 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

  9. Artificial facial nerve reflex restores eyelid closure following orbicularis oculi muscle denervation

    Institute of Scientific and Technical Information of China (English)

    Yujuan Wang; Keyong Li; Jingquan Liu; Dongyue Xu; Yuefeng Rui; Chunsheng Yang

    2010-01-01

    To date, treatment of peripheral facial paralysis has focused on preservation of facial nerve integrity. However, with seriously damaged facial nerve cases, it is difficult to recover anatomical and functional integrity using present therapies. Therefore, the present study utilized artificial facial nerve reflex to obtain orbicularis oculi muscle (OOM) electromyography signals on the uninjured side through the use of implanted recording electrodes. The implanted electrical chips analyzed facial muscle motion on the uninjured side and triggered an electrical stimulator to emit current pulses, which resulted in stimulation of injured OOM contraction and maintained bilateral symmetry and consistency. Following signal recognition, extraction, and computer analysis, electromyography signals in the uninjured OOM resulted in complete eyelid closure, which was consistent with the voltage threshold for eye closure. These findings suggested that artificial facial nerve reflex through the use of implanted microelectronics in unilateral peripheral facial paralysis could restore eyelid closure following orbicularis oculi muscle denervation.

  10. Associations between orbicularis oris thickness and skeletal and dental variables in mixed dentition

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    Taís de Souza Barbosa

    Full Text Available AIM: To evaluate the association between orbicularis oris thickness and skeletal and dental variables in children with mixed dentition. MATERIAL AND METHOD: A convenience sample of 22 children, aged 7 to 12 years, with skeletal Class I and Class II malocclusion and subdivisions were selected. The upper and lower fascicles of the orbicularis oris thicknesses were measured using ultrasound (US by one calibrated examiner, at rest and in the contracted state. Cephalometric radiograph measurements of the hard and soft tissues were calculated by one trained examiner. The results were analyzed by the Pearson and Spearman coefficients. RESULT: The upper and lower fascicles of the orbicularis oris in the contracted state showed a negative correlation with the distance between Ricketts' E-line and the labrale superius (E ┴ Ls. There were positive correlations between the lower face height and the distance between the AB plane and the labrale superius (AB-Ls and between the ANB angle and the distance between E ┴ Ls and Ricketts' E-line and the labrale inferius (E ┴ Li. The lower-incisor distance from the N-Pg plane correlated positively with the distance between AB-Ls and the distance between the E ┴ Ls and E ┴ Li. Overbite and interincisal angle were negatively correlated with the distance between the pogonion and the soft tissue pogonion and the distance between E ┴ Li, respectively. CONCLUSION: Skeletal and dental variables were associated with upper and lower lip position and pogonion thickness, while the upper and lower fascicles of the orbicularis oris thicknesses in the contracted state were associated only with upper lip retrusion.

  11. Identification of proteins involved in desiccation tolerance in the red seaweed Pyropia orbicularis (Rhodophyta, Bangiales).

    Science.gov (United States)

    López-Cristoffanini, Camilo; Zapata, Javier; Gaillard, Fanny; Potin, Philippe; Correa, Juan A; Contreras-Porcia, Loretto

    2015-12-01

    Extreme reduction in cellular water content leads to desiccation, which, if persistent, affects the physiology of organisms, mainly through oxidative stress. Some organisms are highly tolerant to desiccation, including resurrection plants and certain intertidal seaweeds. One such species is Pyropia orbicularis, a rhodophycean that colonizes upper intertidal zones along the Chilean coast. Despite long, daily periods of air exposure due to tides, this alga is highly tolerant to desiccation. The present study examined the proteome of P. orbicularis by 2DE and LC-MS/MS analyses to determine the proteins associated with desiccation tolerance (DT). The results showed that, under natural conditions, there were significant changes in the protein profile during low tide as compared to naturally hydrated plants at high tide. These changes were mainly in newly appeared proteins spots such as chaperones, monodehydroascorbate reductase, and manganese superoxide dismutase, among others. Previously undescribed proteins under desiccation conditions included phycobiliproteins, glyoxalase I, and phosphomannomutase. These changes evidenced that several physiological responses involved in DT are activated during low tide, including decreased photosynthetic activity, increased antioxidant capacity, and the preservation of cell physiology by regulating water content, cell wall structure, and cell volume. Similar responses have been observed in resurrection plants and bryophytes exposed to desiccation. Therefore, the coordinated activation of different desiccation tolerance pathways in P. orbicularis could explain the successful biological performance of this seaweed in the upper intertidal rocky zones. PMID:26154304

  12. Chemical characterization using gas chromatography/mass spectrometry of two extracts from Phyllanthus orbicularis HBK

    International Nuclear Information System (INIS)

    The objective of this paper was the chemical characterization of two extracts from Phyllanthus orbicularis HBK through gas chromatography/mass spectrometry. To this end, maceration with N-hexane and ethyl acetate was used to obtain the respective extracts. The study of the hexane extract identified 17 components in which hydrocarbonate structures prevailed, mainly cyclooctacosane. In the ethyl acetate extract, 19 compounds were detected, being the terpenoids the predominant, although the most abundant was sterol g-sitosterol. For the first time, the identified compounds are reported for this species

  13. 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....... The species are defined by full morphological descriptions, drawings of shells and soft parts, and photographs of shells, and for some of them, the live animals. The known geographical distribution and habitat of each species is also given. While one species is probably commensal with a thallasinidean...

  14. Neoplastic diseases of marine bivalves.

    Science.gov (United States)

    Carballal, María J; Barber, Bruce J; Iglesias, David; Villalba, Antonio

    2015-10-01

    Two types of prevalent neoplastic diseases have been described in marine bivalves of commercial interest: disseminated neoplasia (DN) and gonadal neoplasia. The first involves the excessive proliferation of abnormal cells with unknown origin (probably of hemic source in some cases/species), disseminating through the circulatory system and infiltrating the connective tissue of various organs; the second consists of an abnormal proliferation of undifferentiated germinal cells of the gonad. These two types of bivalve neoplasia fit the criteria of malignant tumors: pleomorphic and undifferentiated cells, rapid and invasive growth, abundance of mitotic figures, metastasis and progressive development often resulting in the death of the affected individual. Different causes have been suggested regarding etiology: genetic alterations, virus, retrotranspons, and contaminants, although it could depend on the mollusk species; evidence of horizontal transmission of clonal cancer cells as the cause of DN spreading in clam Mya arenaria populations has been recently reported. In some species and populations, the neoplastic disorders affect only a few individuals, but in others reach high prevalence. Among the diagnostic methods, DN has been detected by histology and cytologic examination of hemolymph, and with developed specific antibodies. Recently, flow cytometry has also been applied, allowing detecting DNA quantity alteration. Several studies reported many genes and pathways critically involved in neoplastic transformation in Mya arenaria, Mytilus spp. and Ostrea edulis. These genetic studies will allow the development of diagnosis by PCR which can be used in biomonitoring studies. PMID:26146225

  15. Trigeminal Proprioception Evoked by Strong Stretching of the Mechanoreceptors in Müller's Muscle Induces Reflex Contraction of the Orbital Orbicularis Oculi Slow-Twitch Muscle Fibers

    OpenAIRE

    Matsuo, Kiyoshi; Ban, Ryokuya; Ban, Midori; Yuzuriha, Shunsuke

    2014-01-01

    Objective: The mixed orbicularis oculi muscle lacks an intramuscular proprioceptive system such as muscle spindles, to induce reflex contraction of its slow-twitch fibers. We evaluated whether the mechanoreceptors in Müller's muscle function as extrinsic mechanoreceptors to induce reflex contraction of the slow-twitch fibers of the orbicularis oculi in addition to those of the levator and frontalis muscles. Methods: We evaluated in patients with aponeurosis-disinserted blepharoptosis whether ...

  16. Release of orbicularis retaining ligament: an improved method of orbicularis oculi muscle supension blepharo-plasty%眼轮匝肌悬吊法睑袋成形术的改进

    Institute of Scientific and Technical Information of China (English)

    顾云鹏; 郭鑫; 于浩; 王太玲; 王佳琦

    2010-01-01

    Objective To study a improved technique by releasing the orbicularis retaining ligament in orbicularis oculi muscle supension blepharoplasty. Release of the orbicularis retaining ligament could cut off the contact between orbitomalar skin and periosteum at inferior orbital rim, and carry the point of tightening orbitomalar skin in orbicularis oculi muscle supension blepharoplasty. Methods There were 409 patients with apparent orbitmalar fold. The methods of releasing orbicularis retaining ligament and orbital septum fixation were added to improve the orbicularis oculi muscle supension blepharoplasty. Results 409 cases were treated using this method over the past 3 years. All results were satisfactory. No complications were observed. Conclusion This improved method of orbicularis oculi muscle supension blepharoplasty is useful for orbitomalar skin rolling, especially for orbitmalar fold. The release allows effective redraping and upward mobilization of the orbicularis of the lower lid and the premalar soft tissues. This method is a simple, safe and effective procedure for the correction of tear trough deformity and well-demarcated lid/cheek junction in lower eyelid belpharoplasty. It is one of the best choices for lower eyelid blepharoplasty.%目的 探讨在眼轮匝肌悬吊法睑袋成形术中,通过眼轮匝肌支持韧带完全松解,使附着在眶缘骨膜上松弛的皮肤、皮下组织得以充分释放,以达到下睑组织和眶颧组织整体提紧效果的改良手术方法.方法 对409例具有较明显沟槽畸形的患者,在行眼轮匝肌悬吊法睑袋成形术过程中,增加了眼轮匝肌支持韧带离断、韧带断端上提与眶隔筋膜固定的操作,对眼轮匝肌悬吊法进行改进.结果 经术后随访1~3年,全部受术者沟槽畸形改观明显,无1例出现并发症,得到比较满意的疗效.结论 改良的眼轮匝肌悬吊法睑袋成形术,松解了眶颧部皮肤,有利于恢复睑颊复合体的平整自然,对改

  17. Comparative Micro-Anatomy of the Orbicularis Oris Muscle between Chimpanzees and Humans: Evolutionary Divergence of Lip Function

    OpenAIRE

    Rogers, Carolyn R.; Mooney, Mark P.; Smith, Timothy D; Weinberg, Seth M.; Bridget M Waller; Parr, Lisa A.; Docherty, Beth A.; Bonar, Christopher J.; Reinholt, Lauren E.; Deleyiannis, Frederic W.-B.; Siegel, Michael I.; Marazita, Mary L.; Burrows, Anne M.

    2009-01-01

    The orbicularis oris muscle (OOM) plays a role in the production of primate facial expressions and vocalizations, nutrient intake, and in some non-human primates it is used as a prehensile, manipulative tool. Since the chimpanzee (Pan troglodytes) is the closest living relative of humans, a comparison of the OOM between these species may increase our understanding of the morphological specializations related to differing functional demands of their lips and the factors responsible for their d...

  18. 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...

  19. 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.

  20. The chloroplast genome of Phacus orbicularis (Euglenophyceae): an initial datum point for the phacaceae.

    Science.gov (United States)

    Kasiborski, Beth A; Bennett, Matthew S; Linton, Eric W

    2016-06-01

    The Euglenophyceae chloroplast was acquired when a heterotrophic euglenoid engulfed a green alga and subsequently retained the algal chloroplast, in a process known as secondary endosymbiosis. Since this event, Euglenophyceae have diverged widely and their chloroplast genomes (cpGenomes) have as well. Changes to the cpGenome include extensive gene rearrangement and the proliferation of introns, the analyses of which have proven to be useful in examining cpGenome changes throughout the Euglenophyceae. The Euglenales fall into two families, Euglenaceae and Phacaceae. Euglenaceae contains eight genera and at least one cpGenome has been published for each genus. Phacaceae, on the other hand, contains three genera, none of which have had a representative chloroplast genome sequenced. Members of this family have many small disk-shaped chloroplasts that lack pyrenoids. We sequenced and annotated the cpGenome of Phacus orbicularis in order to fill in the large gap in our understanding of Euglenophyceae cpGenome evolution, especially in regard to intron number and gene order. We compared this cpGenome to those of species from both the Euglenaceae and Eutreptiales of the Euglenophyceae phylogenetic tree. The cpGenome showed characteristics that were more derived than that of the basal species Eutreptia viridis, with extensive gene rearrangements and nearly three times as many introns. In contrast, it contained fewer introns than all but one of the previously reported Euglenaceae cpGenomes, had a smaller estimated genome size, and shared greater synteny with two main branches of that family. PMID:27273533

  1. Checklist of the marine bivalves from Peru

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    Carlos Paredes

    2016-08-01

    Full Text Available A checklist of the marine bivalve species from Peru is presented, this list has 401 species which are distributed in 65 families and 195 genera. The taxonomical classification and nomenclature is based on classical and current bibliography including Bernard (1983 and Coan & Valentich-Scott (2012. We give distribution and hábitat information about every species.

  2. 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.

  3. 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.

  4. Middle and Upper Jurassic bivalves from the Iberian Range (Spain)

    OpenAIRE

    Delvene Ibarrola, Graciela

    2002-01-01

    Previous work on Jurassic bivalves from the Iberian Range is reviewed, whereby emphasis is placed on Callovian-Kimmeridgian species. The taxonomy, distribution pattern and ecology of the bivalve fauna occurring in Middle and Upper Jurassic rocks of the Aragonian Branch of the Iberian Range have been analysed. For this purpose 14 sections and 5 additional outcrops, selected according to the abundance of bivalves, were measured in detail and sampled. The rocks studied belong to the Chelva, Yáto...

  5. Approche qualité post-récolte du Platax orbicularis d’aquaculture en milieu tropical insulaire

    OpenAIRE

    Buchet, Vincent; Richard, Bastien; Knockaert, Camille; Maamaatuaiahutapu, Moana; Tamata, Thierry; Teissier, Alexandre

    2011-01-01

    Ce document constitue le rapport final rendant compte des travaux réalisés dans le cadre de la convention n°8.033/MPA/SPE du 2 décembre 2008 modifiée et à l’avenant n° 0680 du 2 février 2011 entre l’Ifremer et le ministère des ressources marines de Polynésie Française. Il est mené en collaboration avec le Service de la Pêche de Polynésie (SPE). L’objet de cette convention était : la définition d’un protocole d’abattage et de conditionnement du Paraha peue (Platax orbicularis) d’élevage. Le...

  6. Rapport de faisabilité de l’estimation de l’âge du Platax (Platax orbicularis) à Tahiti

    OpenAIRE

    Elleboode, Romain; Mahe, Kelig

    2013-01-01

    L’équipe de l’IFREMER du centre de Polynésie et celle de la Cellule Innovation et Valorisation de la Direction des Ressources Marines de Polynésie Française mènent des travaux afin de maîtriser la zootechnie de l’élevage du Platax (Platax orbicularis) en lagon. Des connaissances sur la physiologie de la reproduction s’est faite sur ces animaux, mais aucune information n’est disponible quant à l’évolution de la productivité de ces animaux en fonction de leur croissance (pas de données d’âge). ...

  7. A biomechanical modeling study of the effects of the orbicularis oris muscle and jaw posture on lip shape

    CERN Document Server

    Stavness, Ian; Perrier, Pascal; Demolin, Didier; Payan, Yohan

    2013-01-01

    Purpose: The authors' general aim is to use biomechanical models of speech articulators to explore how possible variations in anatomical structure contribute to differences in articulatory strategies and phone systems across human populations. Specifically, they investigated 2 issues: (a) the link between lip muscle anatomy and variability in lip gestures and (b) the constraints of coupled lip/jaw biomechanics on jaw posture in labial sounds. Method: The authors used a model coupling the jaw, tongue, and face. First, the influence of the orbicularis oris (OO) anatomical implementation was analyzed by assessing how changes in depth (from epidermis to the skull) and peripheralness (proximity to the lip horn center) affected lip shaping. Second, the capability of the lip/jaw system to generate protrusion and rounding, or labial closure, was evaluated for different jaw heights. Results: Results showed that a peripheral and moderately deep OO implementation is most appropriate for protrusion and rounding; a superf...

  8. 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).

  9. Artificially evolved functional shell morphology of burrowing bivalves

    DEFF Research Database (Denmark)

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

    2014-01-01

    The morphological evolution of bivalves is documented by a rich fossil record. It is believed that the shell shape and surface sculpture play an important role for the burrowing performance of endobenthic species. While detailed morphometric studies of bivalve shells have been done, there are alm...

  10. 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.

  11. Phylogeny and diversification patterns among vesicomyid bivalves.

    Directory of Open Access Journals (Sweden)

    Carole Decker

    Full Text Available Vesicomyid bivalves are among the most abundant and diverse symbiotic taxa in chemosynthetic-based ecosystems: more than 100 different vesicomyid species have been described so far. In the present study, we investigated the phylogenetic positioning of recently described vesicomyid species from the Gulf of Guinea and their western Atlantic and Pacific counterparts using mitochondrial DNA sequence data. The maximum-likelihood (ML tree provided limited support for the recent taxonomic revision of vesicomyids based on morphological criteria; nevertheless, most of the newly sequenced specimens did not cluster with their morphological conspecifics. Moreover, the observed lack of geographic clustering suggests the occurrence of independent radiations followed by worldwide dispersal. Ancestral character state reconstruction showed a significant correlation between the characters "depth" and "habitat" and the reconstructed ML phylogeny suggesting possible recurrent events of 'stepwise speciation' from shallow to deep waters in different ocean basins. This is consistent with genus or species bathymetric segregation observed from recent taxonomic studies. Altogether, our results highlight the need for ongoing re-evaluation of the morphological characters used to identify vesicomyid bivalves.

  12. 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.

  13. 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.

  14. Overwiew on selective breeding and genetic improvement in bivalve shellfish

    OpenAIRE

    Boudry, Pierre

    2004-01-01

    Dr. Boudry focussed his talk on oysters, which are the most important bivalve species produced world wide (more than 4 million tons). One of the main characteristic of bivalve aquaculture is that most of the juveniles ("seed or "spat") are collected from natural recruitment (e.g. 100% of the European mussel production). Hatchery propagation is used in the case of introduced species (e.g. Crassostrea gigas in USA) or limited natural recruitment. The most significant genetic improvement ...

  15. Lower Jurassic beds with bivalves in south Slovenia

    OpenAIRE

    Irena Debeljak; Stanko Buser

    1995-01-01

    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, Cochl...

  16. Characteristics of bivalve diversity in typical habitats of China seas

    OpenAIRE

    Fengshan Xu; Junlong Zhang

    2011-01-01

    With vast sea areas, long coastline and complex environmental conditions, the China seas contain various habitats for bivalves. The diversity characteristics of some typical habitats can reflect the molluscan fauna of China seas. Based on our years of work and records from malacologists home and abroad, the bi-valve diversity, habitats and ecological habits in different environments are described, and the distribution characters in different sea areas are analysed. Due to the effects of coast...

  17. Geography of end-Cretaceous marine bivalve extinctions

    Science.gov (United States)

    Raup, David M.; Jablonski, David

    1993-01-01

    Analysis of the end-Cretaceous mass extinction, based on 3514 occurrences of 340 genera of marine bivalves (Mollusca), suggests that extinction intensities were uniformly global; no latitudinal gradients or other geographic patterns are detected. Elevated extinction intensities in some tropical areas are entirely a result of the distribution of one extinct group of highly specialized bivalves, the rudists. When rudists are omitted, intensities at those localities are statistically indistinguishable from those of both the rudist-free tropics and extratropical localities.

  18. 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.

  19. Marine diatoms sustain growth of bivalves in a Mediterranean lagoon

    Science.gov (United States)

    Pernet, Fabrice; Malet, Nathalie; Pastoureaud, Annie; Vaquer, André; Quéré, Claudie; Dubroca, Laurent

    2012-02-01

    Carbon stable isotopes and fatty acids were measured in the suspended particulate organic matter (POM) of the Thau lagoon to study its qualitative temporal changes in relation to environmental factors and to identify the food sources of bivalves over a one-yr-cycle in relation to their growth. Reciprocally, the impact of shellfish farming on POM was also studied. Oysters and mussels were sampled and measured for biometry, stable isotopes and fatty acid composition. Water samples were collected at two sites, both inside and outside of the shellfish farming area, to determine concentrations in POM, chlorophyll a (Chl a) and stable isotopes. Carbon isotopes and fatty acids in bivalves reflected seasonal changes in food sources, which varied consistently with the environment. Seasonal changes in δ13C and fatty acids in the bivalves suggested that dietary phytoplankton contribution varied according to season. Terrestrial organic matter and bacteria can contribute to the diet of bivalves during non-bloom periods. Mussels seemed to rely more on diatoms and less on terrestrial organic matter and bacteria than oysters did, particularly when phytoplankton biomass was low during the summer. Although one- and two-yr-old oysters showed similar δ13C, their fatty acid dynamics differed slightly. Periods of high growth rate in bivalves were mainly fuelled by diatoms, thus highlighting the importance of seasonal blooms of microphytoplankton during the critical period of bivalve growth and gamete production. Although there was no significant effect of shellfish farms on Chl a and POM δ13C, consistent differences indicate that stable isotopes could be used successfully to investigate the effects of bivalve aquaculture.

  20. Epidermoid cyst in the cerebellopontine angle cistern presenting as trigeminal neuralgia. Diagnostic values of the orbicularis oculi reflex and metrizamide CT cisternography - case report -

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, Takashi; Goya, Tomokazu; Kinoshita, Kazuo (Miyazaki Medical College, Miyazaki (Japan)); Fukui, Masashi

    1983-05-01

    This 29-year-old male had been suffering from left trigeminal neuralgia one year prior to admission. Admission was prompted by the development of pain in the third division of the left trigeminal nerve. Physical and neurological examinations were not remarkable except for the facial pain. The orbicularis oculi reflex showed delayed latency of R/sub 1/ on the affected side. CT scans performed pre- and post-contrast enhancement revealed a low density area in the left cerebellopontine angle cistern. Metrizamide CT cisternography clearly revealed the margin of the lesion as the contrast media did not enter into the low density area. A left suboccipital craniectomy was performed. The trigeminal nerve was surrounded by a thin-capsulated mass and cholesteatoma materials. Histological diagnosis was epidermoid cyst. Since this surgical procedure, the trigeminal neuralgia has not recurred for one year. Without objective neurological deficits, it is difficult to distinguish symptomatic trigeminal from idiopathic neuralgia. Therefore, minor change of the orbicularis oculi reflex should help in objectively detecting dysfunction of the trigeminal nerve. Metrizamide CT cisternography is also useful in diagnosis of cystic lesions.

  1. Δ^<5,7>-Sterol Constituents of Some Bivalves

    OpenAIRE

    Teshima, Shin-ichi; Kanazawa, Akio; SHIMAMOTO, Ryuji; テシマ, シンイチ; カナザワ, アキオ; シマモト, リュウジ; 手島, 新一; 金沢, 昭夫; 嶋元, 隆司

    1985-01-01

    The composition of Δ^-sterols and other sterols of six bivalves collected in Okinawa, Japan, was investigated. Sterols were identified by gas-liquid chromatography (GLC) on 1.5% OV—17 and GLC-mass spectrometry. The bivalves examined contained seven Δ^-sterols and a few Δ^-sterols besides Δ^-sterols commonly occurring in marine molluscs. Saxostrea mordax and Tridacna crocea contained cholesta-5,7-dienol as the major sterols (about 50% of total Δ^-sterols), whereas Protostrea hyotis...

  2. Δ^<5,7>-Sterol Constituents of Some Bivalves

    OpenAIRE

    Teshima, Shin-ichi; Kanazawa, Akio; SHIMAMOTO, Ryuji; テシマ, シンイチ; カナザワ, アキオ; シマモト, リュウジ; 手島, 新一; 金沢, 昭夫; 嶋元, 隆司

    1985-01-01

    The composition of Δ^-sterols and other sterols of six bivalves collected in Okinawa, Japan,was investigated. Sterols were identified by gas-liquid chromatography (GLC) on 1.5% OV—17 and GLC-mass spectrometry. The bivalves examined contained seven Δ^-sterols and afew Δ^-sterols besides Δ^-sterols commonly occurring in marine molluscs. Saxostrea mordax andTridacna crocea contained cholesta-5,7-dienol as the major sterols (about 50% of totalΔ^-sterols), whereas Protostrea hyotis and Pinctada ma...

  3. 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

  4. Reconstruction during phase II of unilateral cleft lip improving function of musculus orbicularis oris%单侧唇裂Ⅱ期整复改善口轮匝肌功能

    Institute of Scientific and Technical Information of China (English)

    马新亮; 陈传俊; 韩立显

    2002-01-01

    @@ Background:Nasolabial deformity secondary to operation of cleft lip seriously affect patients' physiological and psychological function.Plasticity or reposition of musculus orbicularis oris received more attention in recent years.Since 1995,nasolabial deformity secondary to operation of unilateral complete cleft lip was reduced in 17 patients,and therapeutic effect is satisfying.

  5. 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

  6. 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.

  7. 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.

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

    NARCIS (Netherlands)

    De Zwaan, A.; Babarro, J.M.F.; Monari, M.; Cattani, O.

    2002-01-01

    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 m

  9. Clinical application of temporal flap pedicled with orbicularis oculi muscle%颞侧眼轮匝肌蒂岛状皮瓣的临床应用

    Institute of Scientific and Technical Information of China (English)

    梁伟强; 张金明; 潘淑娟; 陈宇宏; 储海函

    2008-01-01

    目的 探讨用颞侧眼轮匝肌蒂岛状皮瓣修复眼睑及鼻部皮肤软组织缺损的方法及效果.方法 设计以眼轮匝肌为蒂,以同侧颞区无毛发区为供区的皮瓣,移位并修复上下睑外翻及上下睑和鼻部肿瘤或瘢痕切除后、鼻外伤组织缺损共30例.皮瓣面积为1.0 cm×1.8 cm~2.5 cm×4.5 cm.结果 30例巾除5例早期皮瓣远端出现静脉淤血经保守治疗好转外,全部皮瓣均完全成活,随访3个月至1年,较少遗留瘢痕及继发畸形,功能及外观满意.结论 以眼轮匝肌为蒂的颞侧岛状皮瓣是修复眼睑及鼻部小面积缺损的良好手术材料,具有易于转移、血供可靠、愈合快及供区隐蔽等优点.%Objective To investigate the effect of repairing soft tissue defect of eyelid and nose by using temporal flap pedicled with orbicularis oculi muscle.Methods From 2000,the temporal flaps pedicled with orbicularis oculi muscle were used in 30 cases,including cicatricial ectropion of upper and lower eyelid,tumor or scar in eyelid and nose area,nose tissue defect after injury.The maximal area of skin flap was 1.0 cm×1.8 cm~2.5 cm×4.5 cm.Results All the skin flaps were survived after operations except 5 cases which had problems with venous refluence on the distal part of skin flaps and were improved after conservative treatments.Cases were followed up from 3 months to 1 year,and there were few scars or secondary deformity formation in the donor site.The function and appearance were satisfied.Conclusions The temporal flap pedicled with orbicularis oculi muscle is a reliable material to repair small soft tissue defect of eyelid and nose with easily transferring capacity,reliable blood supply,rapid healing ability and concealed donor site.

  10. Dossier récapitulatif du développement de l’élevage du Platax orbicularis en Polynésie Française

    OpenAIRE

    Coeurdacier, Jean-luc; Gasset, Eric

    2013-01-01

    Platax orbicularis est l’espèce sur laquelle est basé le développement de la pisciculture en Polynésie française. Ce choix a été guidé par le fort potentiel économique de l’espèce dû à sa notoriété sur le marché local du poisson lagonaire estimé à 100 tonnes/an et à la diminution de sa population sauvage. Depuis 2001, date du démarrage d’un programme de développement de la pisciculture lagonaire en Polynésie, les travaux de recherche et développement menés conjointement par le Service de l...

  11. 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.

  12. 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

  13. 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

  14. Bivalves build their shells from amorphous calcium carbonate

    Science.gov (United States)

    Jacob, D. E.; Wirth, R.; Soldati, A. L.; Wehrmeister, U.

    2012-04-01

    One of the most common shell structures in the bivalve class is the prism and nacre structure. It is widely distributed amongst both freshwater and marine species and gives cultured pearls their sought-after lustre. In freshwater bivalves, both shell structures (prism and nacre) consist of aragonite. Formation of the shell form an amorphous precursor phase is a wide-spread strategy in biomineralization and presents a number of advantages for the organisms in the handling of the CaCO3 material. While there is already evidence that larval shells of some mollusk species use amorphous calcium carbonate (ACC) as a transient precursor phase for aragonite, the use of this strategy by adult animals was only speculated upon. We present results from in-situ geochemistry, Raman spectroscopy and focused-ion beam assisted TEM on three species from two different bivalve families that show that remnants of ACC can be found in shells from adult species. We show that the amorphous phase is not randomly distributed, but is systematically found in a narrow zone at the interface between periostracum and prism layer. This zone is the area where spherulitic CaCO3- structures protrude from the inner periostracum to form the initial prisms. These observations are in accordance with our earlier results on equivalent structures in freshwater cultured pearls (Jacob et al., 2008) and show that the original building material for the prisms is amorphous calcium carbonate, secreted in vesicles at the inner periostracum layer. Quantitative temperature calibrations for paleoclimate applications using bivalve shells are based on the Mg-Ca exchange between inorganic aragonite (or calcite) and water. These calibrations, thus, do not take into account the biomineral crystallization path via an amorphous calcium carbonate precursor and are therefore likely to introduce a bias (a so-called vital effect) which currently is not accounted for. Jacob et al. (2008) Geochim. Cosmochim. Acta 72, 5401-5415

  15. Magnetosome-containing bacteria living as symbionts of bivalves

    OpenAIRE

    Dufour, Suzanne C.; Laurich, Jason R; Batstone, Rebecca T; McCuaig, Bonita; Elliott, Alexander, 1983-; Poduska, Kristin M

    2014-01-01

    Bacteria containing magnetosomes (protein-bound nanoparticles of magnetite or greigite) are common to many sedimentary habitats, but have never been found before to live within another organism. Here, we show that octahedral inclusions in the extracellular symbionts of the marine bivalve Thyasira cf. gouldi contain iron, can exhibit magnetic contrast and are most likely magnetosomes. Based on 16S rRNA sequence analysis, T. cf. gouldi symbionts group with symbiotic and free-living sulfur-oxidi...

  16. Relating Productivity Events to Holocene Bivalve Shell Growth Rates

    Science.gov (United States)

    Huntley, J. W.; Krause, R. A.; Kowalewski, M.; Romanek, C. S.; Kaufman, D. S.; Simoes, M. G.

    2007-12-01

    The growth rate of a bivalve can be influenced by many environmental factors that can change during the life of the organism. In this contribution we present initial data from a millennium scale chronology to assess the relationship between ontogenetic growth in the bivalve Semele casali and paleoenvironmental conditions preserved in the shell using growth increment analysis, radiocarbon-calibrated amino acid racemization dating techniques, stable isotopes (C and O) and high spatial resolution (125-150 samples per cm of shell profile) trace element (Ba, Mn) analysis (LA-ICPMS). Time-averaged specimens of S. casali were dredged from two sites at 10 meters and 30 meters depth along the inner continental shelf at Ubatuba Bay in the Southeast Brazilian Bight, an area influenced by productivity pulses triggered by coastal runoff events and coastal upwelling. Seventy-five individual valves were dated using amino acid racemization (aspartic acid). Dates were calculated using an expanded version of a previously published relationship (Barbour Wood et al., 2006 Quaternary Research 323- 331) between aspartic acid ratios and AMS radiocarbon dates of twelve S. casali individuals from the same sampling locations. The resulting time series has complete coverage for the past three thousand years at centennial resolution. From this time series, a sub-sample of dated valves was selected for more detailed growth increment, stable isotope and high-resolution trace element (Ba/Ca and Mn/Ca) analyses. Oceanic productivity is expressed differentially in the trace element profiles of S. casali with elevated Ba/Ca and Mn/Ca ratios capturing nutrient input through coastal runoff events while elevated Ba/Ca and depressed Mn/Ca ratios represent input through coastal upwelling. Fluctuations in Ba/Ca and Mn/Ca are not correlated to fluctuations in relative growth throughout the ontogeny of an individual bivalve, nor are they expected to be as periods of increased productivity are transient

  17. A型肉毒毒素治疗下眼睑轮匝肌肥厚%The efficacy of Botox-A in the treatment of the orbicularis oculi muscle hypertrophy

    Institute of Scientific and Technical Information of China (English)

    赵烨德; 陈祥云

    2012-01-01

    Objective To observe the efficacy of using Botox -A in the treatment of the orbicularis oculi muscle hypertrophy. Methods A total of 27 patients with the orbicularis oculi muscle hypertrophy were involved in the present study with a local injection of Botox -A. 2 injection points on each lower eyelid with the orbicularis oculi muscle hypertrophy.each injection points dose for 1 ~2 units.the patients were followed up within six months after injection. Results Result of treatment in 27 cases was satisfactory, effective time was 4 to 8 months.no complications occurred. Conclusion Botox-A local injection is a safe.effective and reliable treatment for patients with the orbicularis oculi muscle hypertrophy.%目的:观察局部注射A型肉毒毒素治疗下眼睑轮匝肌肥厚的临床效果.方法:采用A型肉毒毒素对27例单纯性眼轮匝肌肥厚患者进行局部注射治疗,每侧选择2个注射点,每注射点剂量为1~2单位,注射后半年内随访.结果:27例患者均取得满意效果,维持时间4~8个月.无并发症发生.结论:A型肉毒毒素是治疗单纯性下眼睑轮匝肌肥厚的安全有效方法.

  18. 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

  19. Filtration in some tropical intertidal bivalves exposed to mercury and cadmium mixtures

    OpenAIRE

    Mohan, C. V.; N. R. Menon; Gupta, T.R.C.

    1986-01-01

    Three species of intertidal filter feeding bivalves (Modiolus carvalhoi, Modiolus sp. and Donax spiculum) exposed to mercury and cadmium filtered significantly less volume of water under individual metal and metal mixture stress. Mercury and cadmium in mixtures interacted additively and more than additively (Synergism) in depressing the filtration rate of the bivalves.

  20. A novel filtering mutualism between a sponge host and its endosymbiotic bivalves.

    Directory of Open Access Journals (Sweden)

    Remi Tsubaki

    Full Text Available Sponges, porous filter-feeding organisms consisting of vast canal systems, provide unique substrates for diverse symbiotic organisms. The Spongia (Spongia sp. massive sponge is obligately inhabited by the host-specific endosymbiotic bivalve Vulsella vulsella, which benefits from this symbiosis by receiving protection from predators. However, whether the host sponge gains any benefit from this association is unclear. Considering that the bivalves exhale filtered water into the sponge body rather than the ambient environment, the sponge is hypothesized to utilize water exhaled by the bivalves to circulate water around its body more efficiently. We tested this hypothesis by observing the sponge aquiferous structure and comparing the pumping rates of sponges and bivalves. Observations of water currents and the sponge aquiferous structure revealed that the sponge had a unique canal system enabling it to inhale water exhaled from bivalves, indicating that the host sponge adapted morphologically to receive water from the bivalves. In addition, the volume of water circulating in the sponge body was dramatically increased by the water exhaled from bivalves. Therefore, this sponge-bivalve association can be regarded as a novel mutualism in which two filter-feeding symbionts promote mutual filtering rates. This symbiotic association should be called a "filtering mutualism".

  1. A novel filtering mutualism between a sponge host and its endosymbiotic bivalves.

    Science.gov (United States)

    Tsubaki, Remi; Kato, Makoto

    2014-01-01

    Sponges, porous filter-feeding organisms consisting of vast canal systems, provide unique substrates for diverse symbiotic organisms. The Spongia (Spongia) sp. massive sponge is obligately inhabited by the host-specific endosymbiotic bivalve Vulsella vulsella, which benefits from this symbiosis by receiving protection from predators. However, whether the host sponge gains any benefit from this association is unclear. Considering that the bivalves exhale filtered water into the sponge body rather than the ambient environment, the sponge is hypothesized to utilize water exhaled by the bivalves to circulate water around its body more efficiently. We tested this hypothesis by observing the sponge aquiferous structure and comparing the pumping rates of sponges and bivalves. Observations of water currents and the sponge aquiferous structure revealed that the sponge had a unique canal system enabling it to inhale water exhaled from bivalves, indicating that the host sponge adapted morphologically to receive water from the bivalves. In addition, the volume of water circulating in the sponge body was dramatically increased by the water exhaled from bivalves. Therefore, this sponge-bivalve association can be regarded as a novel mutualism in which two filter-feeding symbionts promote mutual filtering rates. This symbiotic association should be called a "filtering mutualism".

  2. Hypoglossal-Facial Nerve Reconstruction Using a Y-Tube-Conduit Reduces Aberrant Synkinetic Movements of the Orbicularis Oculi and Vibrissal Muscles in Rats

    Directory of Open Access Journals (Sweden)

    Yasemin Kaya

    2014-01-01

    Full Text Available The facial nerve is the most frequently damaged nerve in head and neck trauma. Patients undergoing facial nerve reconstruction often complain about disturbing abnormal synkinetic movements of the facial muscles (mass movements, synkinesis which are thought to result from misguided collateral branching of regenerating motor axons and reinnervation of inappropriate muscles. Here, we examined whether use of an aorta Y-tube conduit during reconstructive surgery after facial nerve injury reduces synkinesis of orbicularis oris (blink reflex and vibrissal (whisking musculature. The abdominal aorta plus its bifurcation was harvested (N = 12 for Y-tube conduits. Animal groups comprised intact animals (Group 1, those receiving hypoglossal-facial nerve end-to-end coaptation alone (HFA; Group 2, and those receiving hypoglossal-facial nerve reconstruction using a Y-tube (HFA-Y-tube, Group 3. Videotape motion analysis at 4 months showed that HFA-Y-tube group showed a reduced synkinesis of eyelid and whisker movements compared to HFA alone.

  3. Food for thought: Sub-fossil and fossil chelonian remains from Franchthi Cave and Megalopolis confirm a glacial refuge for Emys orbicularis in Peloponnesus (S. Greece)

    Science.gov (United States)

    Vlachos, Evangelos; Delfino, Massimo

    2016-10-01

    Peloponnesus peninsula (S. Greece) shows a remarkable extant chelonian fauna that has received considerable attention from a molecular and morphological point of view. Here we present new evidence from the fossil and sub-fossil record of two important sites in the area, Franchthi Cave and Megalopolis. The archaeological material from Franchthi Cave (Upper Paleolithic - Neolithic/latest Pleistocene - early Holocene) represents food remains from small game prey of the humans that inhabited the cave. The palaeontological material from Megalopolis (Late Pleistocene) comes from old and new excavations. The studied specimens, combined with information from molecular, climatic and zoological works, provide for the first time direct evidence for the presence of the European pond turtle, Emys orbicularis, in the glacial refuge of South Greece that was hypothesized on the basis of the results of molecular investigations. We also describe other chelonian taxa present in the localities, the Hermann's tortoise Testudo hermanni and the Balkan stripe-necked terrapin Mauremys rivulata, and review previously published chelonian material from Peloponnesus.

  4. 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 subsequent impacts on seagrasses by shifting net effects between alleviation of nutrient stress and intensification of sulfide stress. To test this hypothesis, manipulations of light availability and blue mussel (Mytilus edulis) abundance were made in eelgrass (Zostera marina) mesocosms and biogeochemical......, but eelgrass can resist harm from shortterm stress, even during light limitation. These findings suggest that while small-scale bivalve impacts on seagrasses may be variable in oligotrophic estuaries, they have the potential to be negative in eutrophic systems, which are increasing globally. ©...

  5. 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

  6. 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

  7. 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 < 0.05) adverse effects on 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. PMID:27554394

  8. 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.

  9. 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

    , is needed to provide a rigorous assessment of the role of bivalve mariculture in the CO2 cycle. On the other hand, the discussion about the inclusion of shells of cultured bivalves into the carbon trading system should be framed in the context of ecosystem goods and services. Humans culture bivalves...... and shell when constructing a specific CO2 budget for shells for evaluating the potential of including bivalve shells, and not the whole organism, in the carbon trading system. Concluding, an integrated ecosystem approach as well as an understanding of the ecosystems goods and services of bivalve......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...

  10. Marking methods to monitor bivalve habitat; Nimaigai no seisoku monitoring chosa ni mochiiru hoshiki gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Lim, B.K.; Koshikawa, Y.; Sakurai, N. [Kajima Corp., Tokyo (Japan)

    1999-09-30

    Bivalves inhabiting in coastal areas, e.g., asari and shijimi clams, are important fishery resources and helping clean water. The living environments and resources of these bivalves can be followed by releasing the marked bivalves and catching them again. These surveys with marked habitats give the visible results of their living conditions, easily understandable to anyone, even he is not an expert. Traditionally, the bivalves are marked by various methods before being released, e.g., marked with paint, manicure, adhesive or the like, or scratched on part of the shell surfaces. Such a method, however, needs a lot of time and cost for marking a number of bivalves, and may damage their product values, because of the mark they carry. This company has developed a technique for marking bivalves with iron rust and metallic pieces. This technique has no adverse effects on growth and living of the bivalves, and causes no damage of their product values. It has been applied to surveys on environments in which asari clams inhabiting in natural tidelands and artificial seashores. (NEDO)

  11. Selective extinction among Early Jurassic bivalves: A consequence of anoxia

    Science.gov (United States)

    Aberhan, Martin; Baumiller, Tomasz K.

    2003-12-01

    Analyses of taxonomically standardized data sets demonstrate several statistically robust extinction patterns in Early Jurassic bivalve species from northwest Europe and the Andean basins of South America. In both regions, extinction intensities were significantly enhanced in late Pliensbachian and early Toarcian time as compared to all other time intervals. The same intervals (except for the early Toarcian of South America) also represent times of unusual extinction selectivity, with infaunal taxa suffering distinctly more than epifaunal forms. As infaunal suspension feeders are extremely rare components of Early Jurassic oxygen-controlled macrofaunas, these results are entirely compatible with sedimentological and geochemical data suggesting that widespread anoxia was a principal cause of the diversity crisis. Although many biotic traits that enhance survivorship during background times seem to be irrelevant during major mass extinctions, patterns of survivorship selectivity may provide more distinct clues to the causes of less severe mass extinctions.

  12. 眼轮匝肌瓣在下睑袋伴沟槽畸形修复术中的应用%Clinical application of orbicularis flap for eyelid groove deformity

    Institute of Scientific and Technical Information of China (English)

    张本寿; 水祥兵; 储辉; 李增男; 解潮; 徐志久

    2016-01-01

    目的 探讨下睑袋伴明显泪槽和睑颊沟凹陷畸形的矫正方法和效果.方法 采取下睑缘切口,在眼轮匝肌深面分离,显露眶隔及眶下缘骨膜,将眶隔脂肪释放,重置于眶下缘下方与骨膜缝合固定.若填充效果仍不满意,可将多余眼轮匝肌设计成内侧蒂的眼轮匝肌瓣,转移填充于沟槽凹陷畸形处,并缝合固定.结果 本组60例,术后无下睑凹陷和不平整现象.所有患者均获3~12个月随访,见泪槽及睑颊沟均矫正良好,下睑袋消失.结论 眼轮匝肌瓣联合眶隔脂肪转移重置,对矫正伴有沟槽畸形的下睑袋,是一种简单有效的好方法.%Objective To discuss the correction of lower baggy eyelid with severe tear trough and eyelid sulcus (groove deformity) and its therapeutic effect.Methods Through incision at the lower eyelid margin,the dissection was performed at the deep surface of the orbicularis muscle to expose the orbital septum and inferior orbital rim periosteum.The orbital fat which was released from orbital septum was repositioned at the inferior orbital rim and fixed on periosteum.If the depression was not completely corrected,the extra orbicularis fixed with periosteum.If the depression was not completely corrected,the extra orbicularis muscle was designed as muscle flap with interior pedicle to further correct the groove deformity.Results 60 cases were treated with no depression or unsmooth deformity.All the cases were followed up for 3-12 months with satisfactory aesthetic effect.Conclusions Orbicularis flap combined with orbital fat reposition is a simple and effective method for correction of tear trough and eyelid sulcus deformity.

  13. Life history traits to predict biogeographic species distributions in bivalves

    Science.gov (United States)

    Montalto, V.; Rinaldi, A.; Sarà, G.

    2015-10-01

    Organismal fecundity ( F) and its relationship with body size (BS) are key factors in predicting species distribution under current and future scenarios of global change. A functional trait-based dynamic energy budget (FT-DEB) is proposed as a mechanistic approach to predict the variation of F and BS as function of environmental correlates using two marine bivalves as model species ( Mytilus galloprovincialis and Brachidontes pharaonis). Validation proof of model skill (i.e., degree of correspondence between model predictions and field observations) and stationarity (i.e., ability of a model generated from data collected at one place/time to predict processes at another place/time) was provided to test model performance in predicting the bivalve distribution throughout the 22 sites in the Central Mediterranean Sea under local conditions of food density and body temperature. Model skill and stationarity were tested through the estimate of commission (i.e., proportion of species' absences predicted present) and omission (i.e., proportion of presences predicted absent) errors of predictions by comparing mechanistic predicted vs. observed F and BS values throughout the study area extrapolated by lab experiments and literature search. The resulting relationship was reliable for both species, and body size and fecundity were highly correlated in M. galloprovincialis compared to B. pharaonis; FT-DEB showed correct predictions of presence in more than 75 % of sites, and the regression between BS predicted vs. observed was highly significant in both species. Whilst recognising the importance of biotic interactions in shaping the distribution of species, our FT-DEB approach provided reliable quantitative estimates of where our species had sufficient F to support local populations or suggesting reproductive failure. Mechanistically, estimating F and BS as key traits of species life history can also be addressed within a broader, scale-dependent context that surpasses the

  14. Evolutionary implications of endosymbiont diversity within lucinid bivalves

    Science.gov (United States)

    Garcia, A. M.; Thiessen, M.; Aronowsky, A.; Anderson, L.; Bao, H.; Engel, A.

    2007-12-01

    Bacterial endosymbiosis is widespread among Bivalvia. Symbiosis between lucinid bivalves and sulfur-oxidizing (thiotrophic) bacteria has received recent attention, as lucinids are one of the geologically oldest extant bivalve clades to possess endosymbionts. However, the ecological and evolutionary relationships between host and symbiont are poorly understood, and reconstructing the evolutionary history and geological significance of lucinid endosymbiosis requires additional knowledge and characterization of endosymbiont ecology and taxonomic diversity. Our goal was to characterize the bacterial diversity of a modern lucinid habitat in order to evaluate possible lucinid endosymbiont diversity. Host organisms ( Lucinisca nassula and Phacoides pectinatus) and sediment cores were collected from geochemically reducing and sulfide-rich sea grass beds. PCR amplification and sequencing of bacterial 16S rRNA genes from the sediment cores retrieved 13 major taxonomic groups, including equally dominant Chloroflexi, Delta-, and Gammaproteobacteria, and rare Bacteroides, Acidobacteria, Spirochaetes, and Firmicutes. Less than 2% of the sequences were affiliated with uncultured gammaproteobacterial symbiont groups, but were not closely related to the sequences retrieved from the lucinid gills. Moreover, our analyses uncovered multiple gene sequence populations within an individual, as well as across individuals within the same sampling site. Additional habitat-host-symbiont diversity from three other lucinid taxa and from six geographically distinct habitat sites is also expanding the previously understood diversity of thiotrophic endosymbionts, and specifically that the lucinid symbionts are probably not a monophyletic species. These data suggest that thiotrophic bacteria are recruitable for endosymbiosis and are widely distributed in reducing marine environments. But, because of the diversity of bacteria in any one habitat, symbionts may be metabolically and physiologically

  15. Magnetosome-containing bacteria living as symbionts of bivalves.

    Science.gov (United States)

    Dufour, Suzanne C; Laurich, Jason R; Batstone, Rebecca T; McCuaig, Bonita; Elliott, Alexander; Poduska, Kristin M

    2014-12-01

    Bacteria containing magnetosomes (protein-bound nanoparticles of magnetite or greigite) are common to many sedimentary habitats, but have never been found before to live within another organism. Here, we show that octahedral inclusions in the extracellular symbionts of the marine bivalve Thyasira cf. gouldi contain iron, can exhibit magnetic contrast and are most likely magnetosomes. Based on 16S rRNA sequence analysis, T. cf. gouldi symbionts group with symbiotic and free-living sulfur-oxidizing, chemolithoautotrophic gammaproteobacteria, including the symbionts of other thyasirids. T. cf. gouldi symbionts occur both among the microvilli of gill epithelial cells and in sediments surrounding the bivalves, and are therefore facultative. We propose that free-living T. cf. gouldi symbionts use magnetotaxis as a means of locating the oxic-anoxic interface, an optimal microhabitat for chemolithoautotrophy. T. cf. gouldi could acquire their symbionts from near-burrow sediments (where oxic-anoxic interfaces likely develop due to the host's bioirrigating behavior) using their superextensile feet, which could transfer symbionts to gill surfaces upon retraction into the mantle cavity. Once associated with their host, however, symbionts need not maintain structures for magnetotaxis as the host makes oxygen and reduced sulfur available via bioirrigation and sulfur-mining behaviors. Indeed, we show that within the host, symbionts lose the integrity of their magnetosome chain (and possibly their flagellum). Symbionts are eventually endocytosed and digested in host epithelial cells, and magnetosomes accumulate in host cytoplasm. Both host and symbiont behaviors appear important to symbiosis establishment in thyasirids. PMID:24914799

  16. 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...

  17. 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.

  18. Independent phylogenetic origins of methanotrophic and chemoautotrophic bacterial endosymbioses in marine bivalves

    OpenAIRE

    Distel, D L; Cavanaugh, Colleen Marie

    1994-01-01

    The discovery of bacterium-bivalve symbioses capable of utilizing methane as a carbon and energy source indicates that the endosymbionts of hydrothermal vent and cold seep bivalves are not restricted to sulfur-oxidizing chemoautotrophic bacteria but also include methanotrophic bacteria. The phylogenetic origin of methanotrophic endosymbionts and their relationship to known symbiotic and free-living bacteria, however, have remained unexplored. In situ localization and phylogenetic analysis of ...

  19. 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.

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

    OpenAIRE

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

    2012-01-01

    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 o...

  1. 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. PMID:27039134

  2. 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

  3. Trace Element Uptake in Marine Bivalve Shells Constraints from Field- and Laboratory Studies

    Science.gov (United States)

    Klünder, M.; Hippler, D.; Witbaard, R.; Frei, D.; Immenhauser, A.

    2006-12-01

    There is an increasing interest in the use of the trace element signatures recorded in calcium carbonate skeletons of marine organisms as archives of past and present environmental conditions, such as temperature, salinity or nutrition level. Because of their global occurrence in the modern and ancient oceans, the trace element chemistry of bivalve shells might be used as a potential proxy for present and past environmental conditions. If the composition of bivalve shells, for instance, can be shown to represent the environment in which they lived, then shells can be used to investigate conditions in the lifetime of the animal. And as the shell material is sequentially deposited, an understanding of the internal shell structure will enable time- resolution of the analyses. Therefore, the trace element signature of bivalve shells may provide an important record of climate changes and global geochemical cycles. One of the difficulties of using the trace element signatures of bivalve shells as proxies for environmental conditions is that little is known about the mechanisms by which the trace elements are incorporated into the shells. There has been quite an amount of research into the use of bivalve shell chemistry as proxy for one or more environmental parameters, but there are relatively few datasets in which both bivalve shells and the water in which the animals lived have been analysed. It is as yet not clear to what extent the trace element incorporation into bivalve shells is governed by biological processes, like growth rate and metabolism of the animals, or by physical and crystal chemical parameters. An added difficulty is that the existing data do suggest that trace element uptake in bivalve shells may be species specific. Therefore, studies that investigate the relationships between the content of these elements in the shells and the ambient water and the possible incorporation mechanisms are needed if the potential that bivalve shells offer as

  4. 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.

  5. 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.

  6. 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

  7. Bio-accumulation kinetics of radioruthenium in marine bivalves. Laboratory study

    International Nuclear Information System (INIS)

    Three kinds of marine bivalves (wild Saccostrea cucullata, aquacultured Perna viridis and aquacultured Pinctada martens), collected from Daya Bay, the South China Sea, were used to investigate the bio-accumulation of radioruthenium in the glass aquarium with natural seawater (pH 8.20, 35 per mille salinity, filtered by 0.45 μm) at ambient temperature under laboratory feeding conditions. The experimental results show that the stead-state of biology concentration factor (BCF, ml/g) of radioruthenium was approached around 6 days for most species of bivalves. The values of BCF in shells are the highest in organs all the three bivalves. The orders of BCF values (ml x g-1) are as: Perna viridis (33.2) < Saccostrea cucullata (47.0) < Pinctada martensi (208.4) for shells and Saccostrea cucullata (1.5) < Pinctada martensi (2.2) ∼ Perma viridis (2.4) for soft tissues, respectively, after exposed for 14 days. The rate constants of uptake and elimination of radioruthenium on marine bivalves were also discussed by first-order kinetics model. The Pinctada martensi may be applicable to be an indictor for monitoring radioruthenium among the three bivalves. (author)

  8. 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.

  9. Taxonomic Study of Edible Bivalve from Selected Division of Sarawak, Malaysia

    Directory of Open Access Journals (Sweden)

    M.K. Abu Hena

    2012-01-01

    Full Text Available The diversity of edible bivalve was conducted from August 2010 to July 2011 covering eight divisions i.e., Kuching, Sarikei, Sibu, Mukah, Bintulu, Miri, Limbang and Lawas of Sarawak, Malaysia. Samples were collected from native market and fishing village during the study period. All edible bivalves inhabit either in brackish or marine environment and comprised 19 species from 10 families namely Meretrix meretrix, M. lyrata, Paphia undulata, Circe scripta, Solen regularies, Solen lamarckii, Pharella acutidens, Amusium pleuronectes, Anadara granosa, Pholas orientalis, Gluconome virens, Placuna placenta, Crassotrea lugubris, Isognomon ephippium, Polymesoda erosa, P. bengalensis, P. expansa, Anadonta woodina and Pilsbryoconcha exilis. The diversity of edible bivalves was found highest in Kuching and Bintulu compared to other divisions studied in Sarawak. The bivalve species at Sarawak could have economic potentiality in terms of protein source, livelihoods of local tribes and economic value. Study suggests that if the high conservation and management of edible bivalve diversity could establish in the coastal and wetland area of Sarawak, a remarkable and vast economic return could achieve.

  10. Organochlorine pollutants level in teleost fish and bivalve from Egyptian Mediterranean coast and Nile Estuary

    International Nuclear Information System (INIS)

    Residue levels of 15 organochlorine pollutants and 3 aroclors were analyzed by capillary Gas Chromatography GC in fish Mugil cephalus and bivalve Donax sp., collected from three different locations, at EI-Mex bay, Balteem and Rosetta. The studied pollutants were DDT's isomers, HCHs isomers as well as cyclodiene compounds, Mirex, methoxychlor, toxaphene and hexachlorobenzene (HCB), Aroclors 1248, 1254 and 1260 in addition to 10 individual PCBs congeners. Lipid content percentage ranged from 2.2 to 3.6% in fish and 1.0 to 1.5 % in bivalve, as judged by extractable Organic Matter (EOM) values. Lindane dominated the alph-isomer, with highest concentration 4.6 ng/g in fish from EI-Mex. p,p'-DDE dominated other DDTs analogs with the highest concentrations in fish 15.6 ng/g) and bivalve (9.9 ng/g) from Rosetta. Toxaphene was detected in all locations with maximum levels 13.0 and 11.0 ng/g in bivalve and fish respectively, from Rosetta. Aroclor 1248 dominated other aroclors in both fish and bivalve. For individual PCBs 153 congener dominated other congeners with lower chlorinated biphenyls (mono-through penta-chloro-biphenyls) congeners occurred at lower levels except PCB 200 and PCB 206. (author)

  11. 眶区眼轮匝肌蒂岛状皮瓣在眶周皮肤缺损修复中的应用%The technique of periorbital defects reconstruction with island orbicularis oculi myocutaneous flap in orbital zone

    Institute of Scientific and Technical Information of China (English)

    崔雅宁; 王晓军; 刘志飞; 朱琳; 斯楼斌; 乔群

    2011-01-01

    目的 探讨应用眶区眼轮匝肌蒂岛状皮瓣修复眶周皮肤全层缺损的方法与手术技巧。方法 根据缺损的部位、形态及面积,分别应用以上、下眶区眼轮匝肌内侧为蒂的岛状皮瓣修复眶周的皮肤缺损,供区直接缝合。结果 2003年7月至2009年10月,应用上述方法共修复24例,除l例术后皮瓣远端部分坏死,经换药愈合,2例皮瓣表皮坏死未行处理,自行愈合外,其余皮瓣均成活良好。随访6 ~ 24个月,所有皮瓣色泽、质地均良好,与周围组织无明显差别,供区瘢痕不明显,外形满意。结论选择以眼轮匝肌眶部内侧为蒂的岛状皮瓣一期修复眶周皮肤缺损,血供良好,供区隐蔽,术后效果满意。%Objective To investigate the technique of periorbital defects reconstruction with island orbicularis oculi myocutaneous flap in orbital zone. Methods The upper or lower eyelid island orbicularis oculi myocutaneous flap, medially based, were used for the defects of the periorbital area, according to the position, shape and size of the defects. The donor site was closed directly. Results From July 2003 to October 2009,24 patients were treated in this method, the flaps survived totally. The flap proved to be flexible, safe, relatively simple, and provided good functional and aesthetic results with follow up 6 to 24months. Complications were minimal. Conclusions The upper eyelid or lower eyelid island orbicularis oculi myocutaneous flap , medially based, is a satisfied method in repairing periorbital defects in one stage with good blood supply , excellent color texture matching and inconspicuous donor scar and deformity.

  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. The influence of sediment, food and organic ligands on the uptake of copper by sediment-dwelling bivalves

    NARCIS (Netherlands)

    Absil, M.C.P.; Berntssen, M.; Gerringa, L.J.A.

    1996-01-01

    The sediment-dwelling bivalve Macoma balthica was exposed to dissolved copper ina flow-through system in long-term experiments. Unlike another sediment-dwelling bivalve, the suspension feeder Cerastoderma edule (cockle), M. balthica accumulated copper from the sediment, while the cockles did not. Wh

  14. Preliminary estimates of growth parameters for three commercial bivalve species of Peru (Gari solida, Anlacomya ater and Semele solida)

    OpenAIRE

    Urban, H. J.

    1991-01-01

    The parameters of the von Bertalanffy growth equation were estimated, mainly from size-frequency data, for three commercially exploited Peruvian bivalves, Gari solida, Aulacomya ater and Semele solida, collected by divers from "Bahia de Independencia", Pisco, Peru from November 1986 to September 1987 and from January to September 1990. Some related information on the three bivalves in question are also presented.

  15. Labelling and marketing of bivalve and gastropod molluscs retailed in Sardinia, Italy between 2009 and 2013

    Directory of Open Access Journals (Sweden)

    Domenico Meloni

    2015-06-01

    Full Text Available The aim of the present survey was to investigate the correct enforcement of the Community rules on the labelling and marketing of bivalve and gastropod molluscs retailed in Sardinia, Italy between 2009 and 2013. A total of 1500 packages and labels for live bivalve and gastropod molluscs were considered. A total of 375 labels (25% presented non-compliance concerning the wrong trade name and additional wrong or missing information. The highest percentage of anomalous labels has been detected in small-scale retail shops (35% and open-air markets (25% compared with the big retailing chains (20%. The 5% of packages were not in compliance with the European Community rules on packaging of bivalve and gastropod molluscs. The high percentage of non-compliance with the European regulations on labelling results is a strong limitation for the consumers and highlights the need to improve the control system about labelling of seafood products.

  16. 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.

  17. 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

    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...... for bivalve aquaculture be based on a tiered indicator monitoring system that is structured on the principle that increased environmental risk requires increased monitoring effort. More than 1 threshold for each indicator would permit implementation of predetermined impact prevention and mitigation measures......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...

  18. 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.

  19. 皮瓣松解加眼轮匝肌离断法矫治内眦赘皮%Medial epicanthoplasty using skin redraping and orbicularis oculi muscle disconnection

    Institute of Scientific and Technical Information of China (English)

    张建文; 曹思佳; 夏兆骥; 朱洙玉; 于江

    2011-01-01

    目的 探讨一种操作简单、瘢痕隐蔽、适用于各型内眦赘皮的矫正都可获得较好效果的手术方法.方法 依据近年来对于内眦赘皮病理解剖结构研究,认为内眦赘皮主要是由于上下睑眼轮匝肌于内眦韧带起始部位的错位,并影响皮肤的形态所形成,而并非是单纯的皮肤多余.以此研究成果为指导,设计了松解内眦皮肤与服轮匝肌的粘连以及矫正内眦部位眼轮匝肌错位的矫治术式,即皮瓣松解加眼轮匝肌离断法.结果 共矫治内眦赘皮57例,术后内眦部形态美观,眼裂增宽,瘢痕不明显,患者和医者都较满意.结论 所设计术式适应范围较广,对矫治各型内眦赘皮皆能适用,效果较好.%Objective To explore a new simple epicanthoplasty method fit for various types of epicanthus with inconspicuous scar after operation.Methods As the latest studies showed that the anatomical structure of epicanthus is mainly due to the eyelid orbicularis muscle's dislocation at the starting point of the medial canthal tendon,which affects the skin appearance,rather than the traditional view that was merely the excess skin,we released the adhesions between the skin and the inner canthus orbicularis muscle,and corrected the dislocation of orbicularis muscle that was key to the operation,incised along with the line A′→B→A″→ C in the field of interior canthus,separated the subcutaneous fascia tissue,relaxed the subcutaneous fibrous cord,disconnect the orbicularis muscle's attachment point in the inner canthal fold,and then sutured and folded the inner canthal ligament.After sewing up point A′ and point A″,the released skin retracted naturally and formed a new inner canthal contour.Results From June 2008 to June 2009,57 cases of epicanthus patients accepted this surgery.After operation,the appearance of canthus was nice.Eye fissure got widen,and the scar was not obvious.Also there was a high satisfactory rate.Conclusions This

  20. 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

    An open-top chamber was designed for measuring ambient community clearance rate on undisturbed bivalve populations in the field. The chamber was pressed 5-10 cm down in the sediment on the mussel bed. It holds approximately 30-40 cm water column equal to a volume of 43-77 L. It was provided...... 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...

  1. 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

  2. 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...

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. 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

  9. 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...

  10. 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...

  11. Subtle differences between male and female Oystercatchers Haematopus ostralegus in feeding on the bivalve Macoma balthica

    NARCIS (Netherlands)

    Hulscher, JB; Alting, D; Bunskoeke, EJ; Ens, BJ; Heg, D

    1996-01-01

    In this paper an analysis is made of subtle behavioural differences between adult male and female Ovstercatchers feeding on Macoma balthica under field conditions and in captivity. Macoma is a tellinid bivalve that in the Dutch Wadden Sea is mainly preyed upon during spring and summer when it is bur

  12. 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

  13. Uptake of contaminants of emerging concern by the bivalves Anodonta californiensis and Corbicula fluminea.

    Science.gov (United States)

    Ismail, Niveen S; Müller, Claudia E; Morgan, Rachel R; Luthy, Richard G

    2014-08-19

    Uptake of seven contaminants regularly detected in surface waters and spanning a range of hydrophobicities (log D(ow) -1 to 5) was studied for two species of freshwater bivalves, the native mussel Anodonta californiensis and the invasive clam Corbicula fluminea. Batch systems were utilized to determine compound partitioning, and flow-through systems, comparable to environmental conditions in effluent dominated surface waters, were used to determine uptake and depuration kinetics. Uptake of compounds was independent of bivalve type. Log bioconcentration factor (BCF) values were correlated with log D(ow) for nonionized compounds with the highest BCF value obtained for triclocarban (TCC). TCC concentrations were reduced in the water column due to bivalve activity. Anionic compounds with low D(ow) values, i.e., clofibric acid and ibuprofen, were not removed from water, while the organic cation propranolol showed biouptake similar to that of TCC. Batch experiments supported compound uptake patterns observed in flow-through experiments. Contaminant removal from water was observed through accumulation in tissue or settling as excreted pseudofeces or feces. The outcomes of this study indicate the potential utility of bivalve augmentation to improve water quality by removing hydrophobic trace organic compounds found in natural systems. PMID:25017714

  14. 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 =

  15. 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

  16. 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

  17. A double test of the parasite manipulation hypothesis in a burrowing bivalve

    NARCIS (Netherlands)

    Edelaar, P; Drent, J; de Goeij, P

    2003-01-01

    The parasite manipulation hypothesis predicts that parasites should be selected to manipulate host behaviour to facilitate transmission to the next host. The bivalve Macoma balthica burrows less deep when parasitized by the trematode Parvatrema affinis. Shallow burrowing increases the likelihood of

  18. 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.

  19. Depth-related gradients in community structure and relatedness of bivalves and isopods in the Southern Ocean

    Science.gov (United States)

    Brandt, Angelika; Linse, Katrin; Ellingsen, Kari E.; Somerfield, Paul J.

    2016-05-01

    Despite increased research over the last decade, diversity patterns in Antarctic deep-sea benthic taxa and their driving forces are only marginally known. Depth-related patterns of diversity and distribution of isopods and bivalves collected in the Atlantic sector of the Southern Ocean are analysed. The data, sampled by epibenthic sledge at 40 deep-sea stations from the upper continental slope to the hadal zone (774-6348 m) over a wide area of the Southern Ocean, comprises 619 species of isopods and 81 species of bivalves. There were more species of isopods than bivalves in all samples, and species per station varied from 2 to 85 for isopods and from 0 to 18 for bivalves. Most species were rare, with 72% of isopod species restricted to one or two stations, and 45% of bivalves. Among less-rare species bivalves tended to have wider distributions than isopods. The species richness of isopods varied with depth, showing a weak unimodal curve with a peak at 2000-4000 m, while the richness of bivalves did not. Multivariate analyses indicate that there are two main assemblages in the Southern Ocean, one shallow and one deep. These overlap over a large depth-range (2000-4000 m). Comparing analyses based on the Sørensen resemblance measure and Γ+ (incorporating relatedness among species) indicates that rare species tend to have other closely related species within the same depth band. Analysis of relatedness among species indicates that the taxonomic variety of bivalves tends to decline at depth, whereas that of isopods is maintained. This, it is speculated, may indicate that the available energy at depth is insufficient to maintain a range of bivalve life-history strategies.

  20. 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.

  1. 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.

  2. Study of some marine bivalves as the biomonitor candidates for environmental assessment of the Jianzhou Bay by NAA and AAS

    Institute of Scientific and Technical Information of China (English)

    ZhangPei-Qun; WangWen-Qi; 等

    1998-01-01

    Some kinds of marine bivalves were selected as the biomonitor candidates to study the possibility of the environmentalassessmentof the jiaozhou Bay with biomonitors.The contents of 29 elements in bivalve samples were determined by neutron activation analysis and atomic absorption spectrometry.It is found that clam is a suitable kind of marine bivalves as a biomonitor to evaluate the environmental quality of the Jiaozhou Bay.the environmental status of some sampling sites in this marine area wastentatively assessed by the biomonitors of calm and mussel.

  3. New records and a new species of bivalve (Mollusca: Bivalvia) from Miocene hydrocarbon seep deposits, North Island, New Zealand.

    Science.gov (United States)

    Saether, Kristian P; Jingeng, Sha; Little, Crispin T S; Campbell, Kathleen A

    2016-01-01

    Fourteen bivalve taxa belonging to 11 families are present in at least 13 early to middle Miocene hydrocarbon seep deposits in the East Coast Basin, North Island, New Zealand. Among these are at least three new species, one of which, Semeloidea (s. l.) bexhavenensis sp. nov. (Lasaeidae), is described here. New distribution data are recorded for bivalve species in the families Limidae, Propeamussiidae, Malleidae and Solemyidae. Additional morphological details of Gigantidas coseli (Mytilidae) and Pratulum quinarium (Cardiidae) are provided based upon previously unrecorded internal shell features. Palaeoecological analysis indicates that bivalves utilized a broad range of modes of life and niches within the New Zealand Miocene seep environment, and no more than ca. 30% of these bivalve species were likely to have been obligate to seeps. PMID:27615822

  4. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  6. 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

    2016-01-01

    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.

  7. 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

  8. 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

    The Galathea 3 expedition circumnavigated the globe in 2006-2007 and collected marine samples from six continents. Bivalves were collected from harbours, other impacted locations and reference sites, and samples from 57 sites were analyzed for metals and 47 for organotins, to assess current...... contamination levels on a global scale. Metal concentrations in nine bivalve species were normalised to the Mytilidae family using conversion factors based on cosampled species and literature bioconcentration factors. The lowest metal and tributyltin concentrations were below background assessment...... 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...

  9. 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.

  10. Cytotoxicity assessment of antibiofouling compounds and by-products in marine bivalve cell cultures.

    Science.gov (United States)

    Domart-Coulon, I; Auzoux-Bordenave, S; Doumenc, D; Khalanski, M

    2000-06-01

    Short-term primary cell cultures were derived from adult marine bivalve tissues: the heart of oyster Crassostrea gigas and the gill of clam Ruditapes decussatus. These cultures were used as experimental in vitro models to assess the acute cytotoxicity of an organic molluscicide, Mexel-432, used in antibiofouling treatments in industrial cooling water systems. A microplate cell viability assay, based on the enzymatic reduction of tetrazolium dye (MTT) in living bivalve cells, was adapted to test the cytotoxicity of this compound: in both in vitro models, toxicity thresholds of Mexel-432 were compared to those determined in vivo with classic acute toxicity tests. The clam gill cell model was also used to assess the cytotoxicity of by-products of chlorination, a major strategy of biofouling control in the marine environment. The applications and limits of these new in vitro models for monitoring aquatic pollutants were discussed, in reference with the standardized Microtox test. PMID:10806375

  11. Paralytic shellfish toxins in bivalves which are not associated with dinoflagellates.

    Science.gov (United States)

    Ogata, T; Sato, S; Kodama, M

    1989-01-01

    Paralytic shellfish toxins (PSP toxins) were detected in the freshwater bivalve Corbicula sandai collected from Lake Biwa, Shiga Prefecture, Japan, and marine mussel Septifer virgatus from Mutsu Bay where known causative dinoflagellates and their cysts have never been observed. The toxin profile of C. sandai and S. virgatus was considerably different from suspected causative organisms Aphanizomenon flos-aquae and Protogonyaulax spp., respectively. The causative organism(s) responsible for PSP toxins in these waters is at present unknown. PMID:2617541

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

    OpenAIRE

    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 ecosystem as an effect of a coastal engineering project (Nienhuis & Smaal, 1994). The Oosterschelde estuary is a system where mussels are dominant consumers, which is at least partly due to the strong re...

  13. Paleogene marine bivalves of the deep-water Keasey Formation in Oregon, Part III: The heteroconchs

    OpenAIRE

    Hickman, Carole S.

    2015-01-01

    The heteroconch bivalve fauna of the deep-water (>200 m) Keasey Formation in northwestern Oregon records the Eocene–Oligocene climatic transition and replacement of tropical widely-distributed taxa by the cryophilic taxa that dominate modern high-latitude faunas of the North Pacific. Low-diversity assemblages occur in tuffaceous mudstone and siltstone facies of a deep nearshore basin at the onset of subduction on the Cascadia Margin. Six species of anomalodesmatan heteroconchs have been treat...

  14. Investigation of the molecular ageing process of the long-lived bivalve Arctica islandica

    OpenAIRE

    Gruber, Heike

    2013-01-01

    The question on why we age and how ageing proceeds has occupied researchers’ minds for a long time. Demands on research of healthy ageing and geriatric diseases rise with an older growing human population. Thus, studying the mechanisms of ageing in animals with extraordinarily long lifespans could possibly reveal secrets to longevity and healthy ageing. In this study, a short-lived population of the bivalve mollusk Arctica islandica from the Baltic Sea (with a maximum lifesp...

  15. Biogeographic patterns of the marine bivalve Cerastoderma edule along the European coasts

    OpenAIRE

    Krakau, Manuela

    2008-01-01

    The cockle Cerastoderma edule is a common bivalve that inhabits the marine soft-bottom intertidal along European shores. This invertebrate plays a key role in coastal food webs of the Northeast Atlantic coasts due of its high abundances. I studied cockles from 19 sites along the distribution range with the aim to describe the variation of geographic population structures on different analytical levels. Cockles from the Barents Sea to the African Atlantic coast were analysed with respect to th...

  16. The smaller vesicomyid bivalves in the genus Isorropodon (Bivalvia, Vesicomyidae, Pliocardiinae) also harbour chemoautotrophic symbionts

    OpenAIRE

    Rodrigues, Clara F.; Cunha, Marina R.; Olu, Karine; Duperron, Sébastien

    2012-01-01

    Species of Isorropodon are vesicomyid bivalves for which little information is available regarding host phylogeny and bacterial symbioses. In this study we investigated the symbioses in three Isorropodon species from three cold seep areas: Isorropodon bigoti (Gulf of Guinea), Isorropodon megadesmus (Gulf of Cadiz) and Isorropodon perplexum (Eastern Mediterranean). Analysis of bacterial 16S ribosomal RNA gene sequences demonstrated that each vesicomyid species harbours a single symbiont phylot...

  17. 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.

    Pertanika J. Trop. Agric. Sci. 32(1): 85 - 90 (2009) ISSN: 1511-3701 ©Universiti Putra Malaysia Press Received: 20 May 2008 Accepted: 8 October 2008 * Corresponding Author Identification of Lysozyme Activity from Two Edible Bivalves - Perna viridis... (Linnaeus) and Meretrix casta (Chemnitz) Sumita Sharma 1* , Tanu 2 and Anil Chatterji 3 1 National Institute of Oceanography, Dona Paula, Goa, India 2 Banasthali Universiti, Rajasthan 3 Institute of Tropical Aquaculture, Universiti Malaysia Terengganu...

  18. Differentiation potential of human Orbicularis oculi muscle-derived stem cells towards Schwann cells phenotype%诱导人眼轮匝肌来源肌源干细胞向许旺细胞样细胞的分化

    Institute of Scientific and Technical Information of China (English)

    丁维进; 张文俊; 孙美庆; 苏志达; 李翠; 刘安堂; 江华

    2011-01-01

    BACKGROUND: Muscle derived stem cells (MDSCs) can be isolated from human orbicularis oculi muscle and be differentiated to a Schwann cell phenotype which could eventually provide functional benefits for peripheral nerve repair. OBJECTIVE: To induce the differentiation of MDSCs into Schwann cell phenotype. METHODS: ①Under the support of microscope, we collected the discarded human Orbicularis oculi muscle resected in the upper eyelid blepharoplasty and isolate human-MDSCs within it with aid of tri-enzyme digestion and pre-plating technique, and then identify the cells by immunohistochemistry method. ②We isolated Schwann cells and identify the cells by immunohistochemistry method. Through half-harvest method, we would like to prepare conditioned medium from Schwann cell culture. ③We co-culture human-MDSCs with Schwann cell conditioned medium and the transdifferentiated cell morphology was investigated daily under microscope. The common used marker, S-100, GFAP and p75 were stained to identify Schwann cell phenotype with use of immunohistochemistry method. RESULTS AND CONCLUSION: ①We collected human Orbicularis oculi muscle sample from three young female volunteer with their consensus. Human-MDSCs were isolated from Orbicularis oculi muscle and have their desmin positively stained and Sca-1 was positively expressed. ②Schwann cells were isolated and identified with S-100 positively stained at the rate of (97.4±0.7)%. ③The isolated human-MDSCs were successfully transdifferentiated into Schwann cell-like cells with positive expression of S100, GFAP and p75, which would serve as a unanimous evidence of Schwann cell phenotype. Human-MDSCs could be transdifferentiated into Schwann cell-like cells when co-cultured within Schwann cell conditioned medium, which would serve as an alternative candidate for commonly studied Schwann cells in tissue engineering nerve graft.%背景:肌源干细胞的优越性引导学者们尝试从人眼轮匝肌中分离该细胞,同

  19. Dinophysis caudata generated lipophilic shellfish toxins in bivalves from the Nanji Islands, East China Sea

    Science.gov (United States)

    Jiang, Tao; Xu, Yixiao; Li, Yang; Qi, Yuzao; Jiang, Tianjiu; Wu, Feng; Zhang, Fan

    2014-01-01

    A 12-month program of monitoring potentially toxic microalgae (that produce lipophilic shellfish toxins; LSTs) and their toxins in bivalves was conducted from April 2006 to March 2007 in the Nanji Islands, East China Sea. Two Dinophysis species, D. caudata and D. acuminata, were identified, and D. caudata was found to be the dominant species. D. caudata was detected in water samples between April and June 2006, and between February and March 2007. It reached its highest abundances in May, with a mean abundance of 1.38×102 cells/L in surface water and 1.25×102 cells/L in bottom water (blooms, between April and July 2006. All of the cultured bivalves sampled between April and June were contaminated with LSTs, with an average toxicity of 85 μg okadaic acid (OA) eq./100 g meat, which was four times higher than the Chinese regulatory limit (20 μg OA eq./100 g meat). Ten out of fifteen wild samples (66.7%) collected during the same period were positive for LSTs, and contained an average LST toxicity of 45 μg OA eq./100 g meat (more than twice the regulatory value). Cultured Patinopecten yessoensis collected on 15 May 2006 had the highest toxicity, 320 μg OA eq./100 g meat, and relatively high toxicities (80 to 160 μg OA eq./100 g meat) were found in bivalves until the end of July.

  20. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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. 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. 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. PMID:27576351

  4. 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. PMID:27576351

  5. 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.

  6. 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.

  7. Triassic bivalves and the initial marine Mesozoic revolution: A role for predators?

    Science.gov (United States)

    McRoberts, Christopher A.

    2001-04-01

    Marine bivalves document the long-term increase in generic richness through the early Mesozoic. Following the end-Permian crisis, the Early Triassic was marked by a gradual recovery in generic richness (57 Induan and 66 Olenekian genera). Diversity slowly increased in the Middle Triassic (98 Anisian and 121 Ladinian genera) and peaked in the Late Triassic (171 Carnian, 165 Norian, and 143 Rhaetian genera). These data support earlier hypotheses that the recovery following the end-Permian extinction was very gradual and was not completed (in terms of both richness and ecologic complexity) until the Ladinian. Although a Carnian-Norian extinction is not evident in the data and may be a regional event limited to the Tethyan realm, the end-Triassic extinction is profound—fewer than 30 genera (reptiles), which had typically low abundances and limited distribution during the Triassic. Drilling predators, although present during the Triassic, are not considered to be prominent causes of mortality among bivalves. Instead, the infaunalization of bivalves during the Triassic may have been due to several interconnected abiotic and biotic causes associated with the recovery after the end-Permian mass extinction.

  8. 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.

  9. Environmental changes and shallow marine fossil bivalve assemblages of the Lower Cretaceous Miyako Group, NE Japan

    Science.gov (United States)

    Fujino, Shigehiro; Maeda, Haruyoshi

    2013-03-01

    We reconstructed the environmental changes recorded in the Lower Cretaceous Miyako Group via facies analysis and delineated the relationship between depositional facies and the occurrence of diverse marine invertebrate macrofossils. The Miyako Group consists of deposits from alluvial bay-head delta, bay-head delta front, central bay, and lower shoreface to inner shelf depositional settings. Fossil bivalve assemblages responded to shifts in these sedimentary environments. We defined three fossil bivalve assemblages from the central bay and lower shoreface to inner shelf deposits. The assemblages in the inner shelf and central bay deposits are clearly different, even though they occur within similar depositional facies. This contrast in assemblages results from environmental differences between closed and open settings; this interpretation is supported by the occurrence of stenohaline crinoids. We defined a fourth bivalve assemblage in a tsunami deposit intercalated within the bay-head delta front deposits. It consists of polygenic allochthonous shells, some that were derived from an estuarine environment or the shallow seafloor and others that were torn from small reefs.

  10. Analysis of synonymous codon usage patterns in sixty-four different bivalve species

    Science.gov (United States)

    De Moro, Gianluca; Venier, Paola; Pallavicini, Alberto

    2015-01-01

    Synonymous codon usage bias (CUB) is a defined as the non-random usage of codons encoding the same amino acid across different genomes. This phenomenon is common to all organisms and the real weight of the many factors involved in its shaping still remains to be fully determined. So far, relatively little attention has been put in the analysis of CUB in bivalve mollusks due to the limited genomic data available. Taking advantage of the massive sequence data generated from next generation sequencing projects, we explored codon preferences in 64 different species pertaining to the six major evolutionary lineages in Bivalvia. We detected remarkable differences across species, which are only partially dependent on phylogeny. While the intensity of CUB is mild in most organisms, a heterogeneous group of species (including Arcida and Mytilida, among the others) display higher bias and a strong preference for AT-ending codons. We show that the relative strength and direction of mutational bias, selection for translational efficiency and for translational accuracy contribute to the establishment of synonymous codon usage in bivalves. Although many aspects underlying bivalve CUB still remain obscure, we provide for the first time an overview of this phenomenon in this large, commercially and environmentally important, class of marine invertebrates. PMID:26713259

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. Differential reproductive strategies of two bivalves in the Dutch Wadden Sea

    Science.gov (United States)

    Cardoso, Joana F. M. F.; Witte, Johannes IJ.; van der Veer, Henk W.

    2009-08-01

    Cerastoderma edule and Mya arenaria are two common bivalve species in European waters. Longevity and maximum size are much greater in the latter species. Because comparison of species life-history strategies states that a long life span (i.e. high annual survival) generally goes with lower fecundity, we hypothesise that reproductive output would be lower in M. arenaria than in C. edule. In the present paper, we studied the reproductive strategies of these two species in an intertidal and a subtidal area of the western Dutch Wadden Sea, by following seasonal changes in absolute and relative weights of somatic and gonadal tissues in these bivalves. Starting of spawning was similar in the two species, around May, except for intertidal M. arenaria, which initiated spawning in August. Individual energy investment in reproduction was similar for the two species but, unlike M. arenaria, C. edule spawned completely, releasing all energy of gonadal mass in the form of gametes. Mya arenaria used the gonad not only for reproduction but also for storage. In the intertidal area, we found a trade-off between longevity and reproduction, i.e. maximum reproductive output (expressed as a proportion of body mass) was higher in C. edule than in M. arenaria. However, since body size is larger and life span longer in M. arenaria than in C. edule, mean lifetime reproductive output per individual must be higher in the first than in the latter. Based on the differences in reproductive strategies of these two species, we hypothesise that the negative effects of warming climate on bivalve population dynamics in the Wadden Sea will be stronger in C. edule than in M. arenaria.

  18. First record of a pontoniine shrimp (Caridea, Palaemonidae) in association with a boring bivalve of the genus Spengleria (Bivalvia, Euheterodonta, Gastrochaenidae)

    NARCIS (Netherlands)

    Fransen, C.H.J.M.; Meij, van der S.E.T.

    2010-01-01

    During fieldwork in Raja Ampat, West Papua, Indonesia, in 2007, a pontoniine shrimp, most likely belonging to the genus Anchistus, was collected from a coral boring bivalve of the genus Spengleria. This is the first record of a pontoniine shrimp living in association with a boring bivalve. As it pro

  19. 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

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

    International Nuclear Information System (INIS)

    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

  1. 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.

  2. Comparative sensitivity of European native (Anodonta anatina) and exotic (Corbicula fluminea) bivalves to mercury

    Science.gov (United States)

    Oliveira, Patrícia; Lopes-Lima, Manuel; Machado, Jorge; Guilhermino, Lúcia

    2015-12-01

    Pollution is believed to be an important factor modulating the competition between exotic invasive bivalves and their native competitors. Thus, the objective of the present study was to compare the sensitivity of the European native Anodonta anatina and the exotic invasive species Corbicula fluminea to mercury, a ubiquitous environmental contaminant of high concern. In laboratory acute bioassays, adult organisms of both species were exposed independently to mercury for 96 h (31-500 μg/L). The criteria indicative of toxicity were mortality and biomarkers of oxidative stress and damage, neurotoxicity, and energy production changes. Mercury induced mortality in A. anatina (72 h-LC10 and 72 h-LC50 of 14.0 μg/L and 49.6 μg/L, respectively) but not in C. fluminea. The ability of C. fluminea to maintaining the shell closed for considerable periods of time when exposed to high concentrations of mercury and the effective activation (up to 63 μg/L) of mechanisms against the oxidative stress caused by mercury may have contributed to its relatively low sensitivity. In the range of concentrations tested, mercury had no significant effects on the other parameters analysed in C. fluminea. Overall, the findings of the present study, suggest that in real scenarios of competition between C. fluminea and A. anatina populations, the presence of mercury may modulate the process, acting in favour of the exotic species because it is less sensitive to this environmental contaminant than the native bivalve. The results of the present study highlight the need of further investigation on the effects of mercury on the competition between exotic invasive species and their native competitors, especially the effects potentially induced by long-term exposure to low concentrations of this metal, the mechanisms involved in the tolerance to mercury-induced stress, and the potential post-exposure recovery of both exotic invasive and native bivalves. This knowledge is most important for

  3. 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

    the impacts of transfer activities of cultured bivalve shellfish along the European Atlantic coast; identifies hitch hiker species, fouling organisms or infectious agents which can be translocated with a target species. Further, the study highlights the need for thorough, standard risk reduction measures...... designed to minimise the impact on ecosystems worldwide. In a companion paper details of actual transfer activities in Atlantic Europe are presented and all levels of legislation dealing with transfer activities on a global, regional and national scale are carefully reviewed....

  4. Matriz orgânica solúvel do nacre da concha do bivalve Anodonta cygnea

    OpenAIRE

    Lopes, Anabela Rodrigues

    2011-01-01

    A biomineralização da concha dos moluscos é um processo controlado por uma matriz orgânica extracelular secretada para o espaço extrapaleal pelo epitélio calcificante. Já foram realizados alguns estudos dos quais se obtiveram algumas respostas sobre os constituintes da matriz. No entanto, quase todos tiveram como objeto de estudo moluscos das famílias Pteriidae e Pinnidae. Neste trabalho o animal estudado, o bivalve Anodonta cygnea, pertence à família Unionidae da qual se sa...

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

    OpenAIRE

    Plazzi, Federico

    2011-01-01

    The main scope of my PhD is the reconstruction of the large-scale bivalve phylogeny on the basis of four mitochondrial genes, with samples taken from all major groups of the class. To my knowledge, it is the first attempt of such a breadth in Bivalvia. I decided to focus on both ribosomal and protein coding DNA sequences (two ribosomal encoding genes -12s and 16s -, and two protein coding ones - cytochrome c oxidase I and cytochrome b), since either bibliography and my preliminary results con...

  6. 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...

  7. Bivalve growth rate and isotopic variability across the Barents Sea Polar Front

    Science.gov (United States)

    Carroll, Michael L.; Ambrose, William G.; Locke V, William L.; Ryan, Stuart K.; Johnson, Beverly J.

    2014-02-01

    Analysis of bivalve shell increments provides a means to reconstruct long-term patterns in growth histories and assess factors that regulate marine ecosystems, while tissue stable isotopes are indicators of food sources and trophic dynamics. We examined shell growth patterns and tissue stable isotopic composition (δ13C and δ15N) of the hairy cockle (Ciliatocardium ciliatum) in the northwest Barents Sea to evaluate the influence of different water masses and the Polar Front on growth rates and food sources and to assess the influence of climatic variability on ecological processes over seasonal to decadal scales. Shell growth rates were highest in Atlantic water, intermediate in Arctic water, and lowest at the Polar Front. Temporal patterns of ontogenetically-adjusted growth (SGI) were negatively correlated with the Atlantic Multidecadal Oscillation (AMO), local precipitation and ice-free days. The highest growth occurred during colder periods with more sea ice, while lower growth was associated with warmer periods and less sea ice. Stable isotope values of lipid-extracted tissues from Atlantic water cockles were enriched in δ13C by up to 2.1‰ and δ15N by 1.5‰ compared to animals from Arctic waters. Distinct seasonal and water mass variations in stable isotopic values reflect spatial and temporal variability in food supplies to the bivalves in this region on small spatial scales. Overall, Atlantic waters supported the highest growth rates, the most complex trophic webs, and the greatest sensitivity to interannual variability in environmental conditions. Bivalves from Arctic waters were the most distinct of the three groups in their response to regional climate forcing and local environmental manifestations of those conditions. The Polar Front exhibits growth and isotopic characteristics predominantly of the Atlantic domain. These results demonstrate that integrating results of sclerochronological and stable isotopic analyses of benthic bivalves provide

  8. Filter-feeding bivalves can remove avian influenza viruses from water and reduce infectivity

    OpenAIRE

    Faust, Christina; Stallknecht, David; Swayne, David; Brown, Justin

    2009-01-01

    Avian influenza (AI) viruses are believed to be transmitted within wild aquatic bird populations through an indirect faecal–oral route involving contaminated water. This study examined the influence of filter-feeding bivalves, Corbicula fluminea, on the infectivity of AI virus in water. Clams were placed into individual flasks with distilled water inoculated 1:100 with a low pathogenic (LP) AI virus (A/Mallard/MN/190/99 (H3N8)). Viral titres in water with clams were significantly lower at 24 ...

  9. 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...... of the fauna; only in part can it be explained by the cumulative effect of generations of bivalves inhabiting this coastal environment. The high density and diversity and the wide range of shell morphologies allow interpretation of different modes of life in this variable environment with many...... from 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...

  10. 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.

  11. Organochlorine pesticides in Piracicaba river basin (São Paulo/Brazil: a survey of sediment, bivalve and fish

    Directory of Open Access Journals (Sweden)

    Daniela Mariano Lopes da Silva

    2008-01-01

    Full Text Available The main objective of this paper was to evaluate the level of occurrence of the organochlorine compounds in samples of sediments, bivalves and two fish species collected in the Piracicaba River basin (São Paulo, Brazil. The isomers alpha and gamma of HCH and Heptachlor were most frequently detected in samples of sediments and specimens of bivalve and fish. Therefore, although the levels of these compounds found were not critically high, they are still found in the environment. This fact suggests that they are still being used, despite the fact that the use of these compounds was outlawed more than twenty years ago.

  12. A kinetic approach to assess oxidative metabolism related features in the bivalve Mya arenaria.

    Science.gov (United States)

    González, Paula Mariela; Abele, Doris; Puntarulo, Susana

    2012-12-01

    Electron paramagnetic resonance uses the resonant microwave radiation absorption of paramagnetic substances to detect highly reactive and, therefore, short-lived oxygen and nitrogen centered radicals. Previously, steady state concentrations of nitric oxide, ascorbyl radical (A·) and the labile iron pool (LIP) were determined in digestive gland of freshly collected animals from the North Sea bivalve Mya arenaria. The application of a simple kinetic analysis of these data based on elemental reactions allowed us to estimate the steady state concentrations of superoxide anion, the rate of A· disappearance and the content of unsaturated lipids. This analysis applied to a marine invertebrate opens the possibility of a mechanistic understanding of the complexity of free radical and LIP interactions in a metabolically slow, cold water organism under unstressed conditions. This data can be further used as a basis to assess the cellular response to stress in a simple system as the bivalve M. arenaria that can then be compared to cells of higher organisms. PMID:22829190

  13. Evaluation of the effects of candidate molluscicides on two nontarget bivalves

    Science.gov (United States)

    Waller, D.L.; Marking, L.L.; Rach, J.J.

    1992-01-01

    A variety of molluscicides have been proposed for use in control of zebra mussels (Dreissena polymorpha), but their effect on nontarget aquatic organisms has not been evaluated. Standard methods were adapted for assessing the toxicity of candidate molluscicides to two nontarget bivalves. Fingernail clams, Musculium transversum, and the fawnfoot mussel, Truncilla donaciformis, were selected to represent the two families of native bivalves. Test organisms were collected from pools 6 to 9 of the Upper Mississippi River near La Crosse, WI. Static acute toxicity tests were conducted for 48 hours followed by a 96-hour monitoring period in untreated water to more fully assess survival and mortality. Toxicity data were analyzed by probit analysis to give LC sub(50) values and 95% confidence limits. The same chemicals as those tested at Ohio State University were evaluated against zebra mussels. Results from these studies and those conducted at Ohio State University will be used to evaluate the effectiveness of chemicals in zebra mussel control and their potential hazard to nontarget organisms.

  14. 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.

  15. Ultrastructure of the Interlamellar Membranes of the Nacre of the Bivalve Pteria hirundo, Determined by Immunolabelling.

    Science.gov (United States)

    Osuna-Mascaró, Antonio J; Cruz-Bustos, Teresa; Marin, Frédéric; Checa, Antonio G

    2015-01-01

    The current model for the ultrastructure of the interlamellar membranes of molluscan nacre imply that they consist of a core of aligned chitin fibers surrounded on both sides by acidic proteins. This model was based on observations taken on previously demineralized shells, where the original structure had disappeared. Despite other earlier claims, no direct observations exist in which the different components can be unequivocally discriminated. We have applied different labeling protocols on non-demineralized nacreous shells of the bivalve Pteria. With this method, we have revealed the disposition and nature of the different fibers of the interlamellar membranes that can be observed on the surface of the nacreous shell of the bivalve Pteria hirundo by high resolution scanning electron microscopy (SEM). The minor chitin component consists of very thin fibers with a high aspect ratio and which are seemingly disoriented. Each fiber has a protein coat, which probably forms a complex with the chitin. The chitin-protein-complex fibers are embedded in an additional proteinaceous matrix. This is the first time in which the sizes, positions and distribution of the chitin fibers have been observed in situ.

  16. Ultrastructure of the Interlamellar Membranes of the Nacre of the Bivalve Pteria hirundo, Determined by Immunolabelling.

    Directory of Open Access Journals (Sweden)

    Antonio J Osuna-Mascaró

    Full Text Available The current model for the ultrastructure of the interlamellar membranes of molluscan nacre imply that they consist of a core of aligned chitin fibers surrounded on both sides by acidic proteins. This model was based on observations taken on previously demineralized shells, where the original structure had disappeared. Despite other earlier claims, no direct observations exist in which the different components can be unequivocally discriminated. We have applied different labeling protocols on non-demineralized nacreous shells of the bivalve Pteria. With this method, we have revealed the disposition and nature of the different fibers of the interlamellar membranes that can be observed on the surface of the nacreous shell of the bivalve Pteria hirundo by high resolution scanning electron microscopy (SEM. The minor chitin component consists of very thin fibers with a high aspect ratio and which are seemingly disoriented. Each fiber has a protein coat, which probably forms a complex with the chitin. The chitin-protein-complex fibers are embedded in an additional proteinaceous matrix. This is the first time in which the sizes, positions and distribution of the chitin fibers have been observed in situ.

  17. Assessment and Molecular Characterization of Human Intestinal Parasites in Bivalves from Orchard Beach, NY, USA

    Directory of Open Access Journals (Sweden)

    Freda F. Tei

    2016-03-01

    Full Text Available Bivalves have been shown to be carriers of the human intestinal parasites Cryptosporidium parvum and Toxoplasma gondii. The goal of this study is to determine the prevalence of protozoan parasites in mollusks of New York City using a polymerase chain reaction (PCR-based assay. Four species of mollusks, Mya arenaria, Geukensia demissa, Crassostrea virginica, and Mytilis edulis, were collected from Orchard Beach, NY in the fall of 2014, totaling 159 specimens. Each individual mollusk was dissected to harvest the digestive gland, the mantle, the gills, the foot and the siphon. The tissues were assayed for the presence of Cryptosporidium parvum, Giardia lamblia, and Toxoplasma gondii DNA by using primers that target parasite-specific genes. C. parvum was found at a prevalence of 50%, 11.3%, and 1%, respectively, in Mya arenaria, G. demissa, and Mytilis edulis. C. parvum DNA was detected in all the tissues of these bivalve species, except the gills. Furthermore, G. lamblia was detected in Mya arenaria, G. demissa, Crassostrea virginica and Mytilis edulis at a prevalence of 37.5%, 4.5%, 60%, and 20.6%, respectively, while T. gondii DNA was not detected.

  18. 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.

  19. Assessment and Molecular Characterization of Human Intestinal Parasites in Bivalves from Orchard Beach, NY, USA.

    Science.gov (United States)

    Tei, Freda F; Kowalyk, Steven; Reid, Jhenelle A; Presta, Matthew A; Yesudas, Rekha; Mayer, D C Ghislaine

    2016-04-01

    Bivalves have been shown to be carriers of the human intestinal parasites Cryptosporidium parvum and Toxoplasma gondii. The goal of this study is to determine the prevalence of protozoan parasites in mollusks of New York City using a polymerase chain reaction (PCR)-based assay. Four species of mollusks, Mya arenaria, Geukensia demissa, Crassostrea virginica, and Mytilis edulis, were collected from Orchard Beach, NY in the fall of 2014, totaling 159 specimens. Each individual mollusk was dissected to harvest the digestive gland, the mantle, the gills, the foot and the siphon. The tissues were assayed for the presence of Cryptosporidium parvum, Giardia lamblia, and Toxoplasma gondii DNA by using primers that target parasite-specific genes. C. parvum was found at a prevalence of 50%, 11.3%, and 1%, respectively, in Mya arenaria, G. demissa, and Mytilis edulis. C. parvum DNA was detected in all the tissues of these bivalve species, except the gills. Furthermore, G. lamblia was detected in Mya arenaria, G. demissa, Crassostrea virginica and Mytilis edulis at a prevalence of 37.5%, 4.5%, 60%, and 20.6%, respectively, while T. gondii DNA was not detected. PMID:27043590

  20. 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.

  1. 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.

  2. 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.

  3. 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

    2016-01-01

    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 health risk of Cd (based on the estimated target hazard quotients, THQ) via consumption of M. meretrix at pH 7.8 and 7.4 significantly increased 1.21 and 1.32 times respectively, suggesting a potential threat to seafood safety. The ocean acidification-induced increase in Cd accumulation may have occurred due to (i) the ocean acidification increased the concentration of Cd and the Cd2+/Ca2+ 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.

  4. 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.

  5. 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

  6. Carbon isotope signatures reveal that diet is related to the relative sizes of the gills and palps in bivalves

    NARCIS (Netherlands)

    Compton, Tanya J.; Kentie, Rosemarie; Storey, Andrew W.; Veltheim, Inka; Pearson, Grant B.; Piersma, Theunis

    2008-01-01

    In marine bivalves, the relative sizes of the gills and palps appear to be a useful functional trait that reflect feeding mode, i.e. suspension feeders have relatively larger gills than palps for pumping, whereas deposit feeders have relatively larger palps than gills for sorting. Also, within a spe

  7. Relationship of Parasites and Pathologies to Contaminant Body Burden in Sentinel Bivalves: NOAA Status and Trends `Mussel Watch? Program

    OpenAIRE

    Kim, Yungkul; Powell, Eric N.; Wade, Terry L.; Presley, Bobby J.

    2008-01-01

    Relationship of Parasites and Pathologies to Contaminant Body Burden in Sentinel Bivalves: NOAA Status and Trends `Mussel Watch? Program correspondence: Corresponding author. (Kim, Yungkul) (Kim, Yungkul) Haskin Shellfish Research Laboratory Rutgers University 6959 Miller Ave Port Norris NJ 08349-3167 - (Kim, Yungkul) UNITED STATES (Kim, Yungkul) Haskin Shellfish Research Laboratory Rutgers University 6959 Miller ...

  8. 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.

  9. Studies on the causes of mortality of the estuarine bivalve Macoma balthica under conditions of (near) anoxia

    NARCIS (Netherlands)

    De Zwaan, A.; Babarro, J.M.F.

    2001-01-01

    Survival of the bivalve Macoma balthica in (near) anoxic seawater was studied in a static system and a flow-through system and compared with emersed exposure to air and NZ In the static system, a decrease in pH and exponential accumulation of sulphide in the incubation medium were observed, indicati

  10. 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

  11. 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

  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. Influence of incubation conditions on the anoxic survival of marine bivalves. Static and semi-static incubations

    NARCIS (Netherlands)

    De Zwaan, A.; Cattani, O.; Vitali, G.; Cortesi, P.

    2001-01-01

    In a comparative study of 4 bivalve species we show that the apparent widely different tolerances in survival time observed in a closed system filled with N-2-gassed seawater is mainly due to the experimental conditions. Both a high dose of cadmium and the antibiotic chloramphenicol increase surviva

  14. 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.

  15. 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

  16. 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

  17. Contrasting behavioral and feeding strategies recorded by tidal-flat bivalve trace fossils from the Upper Carboniferous of eastern Kansas

    Science.gov (United States)

    Mangano, M.G.; Buatois, L.A.; West, R.R.; Maples, C.G.

    1998-01-01

    Upper Carboniferous tidal-flat deposits near Waverly, eastern Kansas (Stull Shale Member, Kanwaka Shale Formation), host abundant and very well-preserved trace fossils attributed to the activity of burrowing bivalves. Thin shell lenses with an abundant bivalve fauna area associated with the ichnofossil-bearing beds and afford an unusual opportunity to relate trace fossils to their makers. Two distinctive life and feeding strategies can be reconstructed on the basis of trace fossil analysis and functional morphology. Lockeria siliquaria hyporeliefs commonly are connected with vertical to inclined, truncated endichnial shafts in the absence of horizontal locomotion traces. These structures record vertical and oblique displacement through the sediment, and suggest relatively stable domiciles rather than temporary resting traces as typically considered. Crowded bedding surfaces displaying cross-cutting relationships between specimens of L. siliquaria and differential preservation at the top (concave versus convex epireliefs) record a complex history of successive events of colonization, erosion, deposition, and recolonization (time-averaged assemblages). Irregujlar contours of some large hypichnia indicate the cast of the foot, while other outlines closely match the anterior area of Wilkingia, its suggested tracemaker. Relatively stable, vertical to inclined life positions and dominanit vertical mobility suggest a filter-feeding strategy. Moreover, the elongate shell and pallial sinus of Wilkingia providfe a strong independent line of evidence for an opisthosiphonate, moderately deep-tier inhabitant. Wilingia may represent a pioneer attempt at siphon-feeding in the late Paleozoic, preceding the outcome of the Mesozoic infaunal radiation. A second strategy is represented by Lockeia ornata and association locomotionm and locomotion/feding structures. Lockeia ornata is commonly connected with chevron locomotion traces that record the bifurcated foot of a protobranch

  18. A Large Metabolic Carbon Ccontribution to the δ13C Record in Marine Aragonitic Bivalve Shells

    Science.gov (United States)

    Gillikin, D. P.; Lorrain, A.; Dehairs, F.

    2006-12-01

    The stable carbon isotopic signature archived in bivalve shells was originally thought to record the δ13C of seawater dissolved inorganic carbon (δ13C-DIC). However, more recent studies have shown that the incorporation of isotopically light metabolic carbon (M) significantly affects the δ13C signal recorded in biogenic carbonates. To assess the M contribution to Mercenaria mercenaria shells collected in North Carolina, USA, we sampled seawater δ13C-DIC, tissue, hemolymph and shell δ13C. We found up to a 4‰ decrease through ontogeny in shell δ13C in a 23 year old individual. There was no correlation between shell height or age and tissue δ13C. Thus, the ontogenic decrease observed in the shell δ13C could not be attributed to changes in food sources as the animal ages leading to more negative metabolic CO2, since this would require a negative relationship between tissue δ13C and shell height. Hemolymph δ13C, on the other hand, did exhibit a negative relationship with height, but the δ13C values were more positive than expected, indicating that hemolymph may not be a good proxy of extrapallial fluid δ13C. Nevertheless, the hemolymph data indicate that respired CO2 does influence the δ13C of internal fluids and that the amount of respired CO2 is related to the age of the bivalve. The percent metabolic C incorporated into the shell (%M) was significantly higher (up to 37%) than has been found in other bivalve shells, which usually contain less than 10 %M. Attempts to use shell biometrics to predict %M could not explain more than ~60% of the observed variability. Moreover, there were large differences in the %M between different sites. Thus, the metabolic effect on shell δ13C cannot easily be accounted for to allow reliable δ13C-DIC reconstructions. However, there does seem to be a common effect of size, as all sites had indistinguishable slopes between the %M and shell height (+0.19% per mm of shell height).

  19. 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

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

    Science.gov (United States)

    Takesue, Renee K.; Bacon, Charles R.; Thompson, Janet K.

    2008-11-01

    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 Carré et al. [Carré M., Bentaleb I

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

    Directory of Open Access Journals (Sweden)

    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.

  2. 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

    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. 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...

  4. Physiological status and intersex in the endobenthic bivalve Scrobicularia plana from thirteen estuaries in northwest France.

    Science.gov (United States)

    Tankoua, O Fossi; Amiard-Triquet, C; Denis, F; Minier, C; Mouneyrac, C; Berthet, B

    2012-08-01

    The bivalve Scrobicularia plana, an important species for the structure and functioning of estuarine and coastal mudflats, was studied in thirteen sites from NW France differing by their degree of contamination to document the presence of reproduction impairments (intersex, sex ratio, gonadosomatic indices) in relation to the condition revealed by using hepatosomatic and condition indices. In agreement with recent studies in other European estuaries, intersex was revealed in all the studied estuaries, including sites the chemical and ecological status of which is considered "good" according to the criteria of the European Water Framework Directive. The presence of endocrine disrupting chemicals (EDCs) could result in such disturbances. Our results re-inforce the concern linked to the subtle effects of EDCs, which are active at very low doses, often in the absence of any major sign of toxicity. However at this stage, no clear link may be established between intersex and population effects. PMID:22537660

  5. Influence of an altered salinity regime on the population structure of two infaunal bivalve species

    Science.gov (United States)

    McLeod, Rebecca J.; Wing, Stephen R.

    2008-07-01

    Hydrological alterations in watersheds have changed the flows of freshwater to many nearshore marine environments. The ensuing alterations to the salinity environment of coastal waters may have implications for species distribution. This study describes the response of two common bivalves to a modified salinity environment imposed by freshwater inputs from a hydroelectric power station in Doubtful Sound, New Zealand. Populations of Austrovenus stutchburyi and Paphies australis inhabiting river deltas near the outflow of the power station in inner Doubtful Sound were more than an order of magnitude smaller in abundance than populations in neighbouring Bradshaw Sound where the salinity regime is unaltered. In addition, there was a lack of small size classes of both species in inner Doubtful Sound, suggesting that these populations are unsustainable over the long term (10-20 years). Laboratory experiments demonstrated that sustained exposure (>30 days) to low salinity (food webs of Fiordland's shallow soft sediment communities.

  6. Bivalves as indicators of environmental variation and potential anthropogenic impacts in the southern Barents Sea.

    Science.gov (United States)

    Carroll, Michael L; Johnson, Beverly J; Henkes, Gregory A; McMahon, Kelton W; Voronkov, Andrey; Ambrose, William G; Denisenko, Stanislav G

    2009-01-01

    Identifying patterns and drivers of natural variability in populations is necessary to gauge potential effects of climatic change and the expected increases in commercial activities in the Arctic on communities and ecosystems. We analyzed growth rates and shell geochemistry of the circumpolar Greenland smooth cockle, Serripes groenlandicus, from the southern Barents Sea over almost 70 years between 1882 and 1968. The datasets were calibrated via annually-deposited growth lines, and growth, stable isotope (delta(18)O, delta(13)C), and trace elemental (Mg, Sr, Ba, Mn) patterns were linked to environmental variations on weekly to decadal scales. Standardized growth indices revealed an oscillatory growth pattern with a multi-year periodicity, which was inversely related to the North Atlantic Oscillation Index (NAO), and positively related to local river discharge. Up to 60% of the annual variability in Ba/Ca could be explained by variations in river discharge at the site closest to the rivers, but the relationship disappeared at a more distant location. Patterns of delta(18)O, delta(13)C, and Sr/Ca together provide evidence that bivalve growth ceases at elevated temperatures during the fall and recommences at the coldest temperatures in the early spring, with the implication that food, rather than temperature, is the primary driver of bivalve growth. The multi-proxy approach of combining the annually integrated information from the growth results and higher resolution geochemical results yielded a robust interpretation of biophysical coupling in the region over temporal and spatial scales. We thus demonstrate that sclerochronological proxies can be useful retrospective analytical tools for establishing a baseline of ecosystem variability in assessing potential combined impacts of climatic change and increasing commercial activities on Arctic communities. PMID:19394657

  7. 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.

  8. Emerging and endemic types of Ostreid herpesvirus 1 were detected in bivalves in China.

    Science.gov (United States)

    Bai, Changming; Wang, Chongming; Xia, Junyang; Sun, Hailin; Zhang, Shuai; Huang, Jie

    2015-01-01

    Viral infection caused by Ostreid herpesvirus 1 (OsHV-1) is one of the proximate causes of mass mortalities of cultivated bivalves around the world. The emergence and spread of different variants of OsHV-1 accompanied by different epidemiological characteristics have been reported frequently in different countries around the world. In this paper, we present a study of the detection of OsHV-1 DNA and their variations from 1599 samples over 18 species collected in 27 aquaculture sites and two food markets during 2001-2013 in China. All of the samples were examined by a nested PCR assay targeting the C2/C6 fragment of OsHV-1 followed by sequencing. Our results showed 338 individuals (21.1%) of seven species sampled from 14 (14/27=51.9%) sites and the two food markets were positive for viral DNA. Sequencing of 289 PCR products revealed 24 virus types. No shared virus type was found among different countries with 47 types (23 in Japan, 16 in France, 2 in South Korea and 1 in each country of Australia, USA, Ireland, New Zealand, Mexico and China) identified in previous studies. As previously reported, two main phylogenetic groups were identified by phylogenetic analysis based on the 71 virus types; within which 6 separate clades were identified. Our results also demonstrated that two clades were associated with abnormal mortalities of the scallop, Chlamys farrier and the calm, Scapharca broughtonii in China. These findings indicated that cultivated bivalves may face potential threats from OsHV-1 types found in our study. PMID:25483846

  9. Strong biological controls on Sr/Ca ratios in aragonitic marine bivalve shells

    Science.gov (United States)

    Gillikin, David Paul; Lorrain, Anne; Navez, Jacques; Taylor, James W.; André, Luc; Keppens, Eddy; Baeyens, Willy; Dehairs, Frank

    2005-05-01

    It is well known that skeletal remains of carbonate secreting organisms can provide a wealth of information about past environments. Sr/Ca ratios have been successfully used as a temperature proxy in corals and sclerosponges. Previous work on aragonitic bivalve shells has not been conclusive but suggests a major control of growth rate on Sr/Ca ratios. As many studies have used bivalve growth rates to determine temperature, we tested if Sr/Ca ratios could predict temperature through its relationship with growth rate. Shells from the two species of clams from the same family (veneroidea) studied here, Saxidomus giganteus and Mercenaria mercenaria, show vastly different seasonal Sr/Ca profiles. A strong relationship between average annual Sr/Ca ratios and annual growth rate was found in S. giganteus shells from both Washington (R2 = 0.87) and Alaska (R2 = 0.64), USA, but not in M. mercenaria shells from North Carolina, USA. Furthermore, the Sr/Ca-growth rate relationship was also evident upon a more detailed inspection of subannual growth rates in S. giganteus (R2 = 0.73). Although there were significant positive correlations between Sr/Ca ratios and temperature in S. giganteus shells, the correlations were weak (0.09 control in either clam species, since thermodynamics predict a negative correlation between Sr/Ca ratios and temperature in aragonite. This points toward dominance of biological processes in the regulation of Sr2+. This is also reflected by the largely differing Sr/Ca partition coefficients (DSr) in these shells (DSr ≈ 0.25), when compared to inorganic, coral, and sclerosponge studies (DSr ≈ 1), all of which show a negative dependence of Sr/Ca on temperature. We suggest that caution be taken when using Sr/Ca in any biogenic aragonite as a temperature proxy when the DSr greatly deviates from one, as this indicates the dominance of biological controls on Sr/Ca ratios.

  10. The application of undermining orbicularis oculi muscle from orbital rim for the correction of tear trough deformity and palabromalar groove in lower blepharoplasty%剥离弓状缘眼轮匝肌在伴有泪槽和睑颊沟的眼袋整复中的应用

    Institute of Scientific and Technical Information of China (English)

    郑亚荣; 刘凯; 李青峰; 李锋; 洪素庄

    2012-01-01

    Objective To evaluate the role of undermining orbicularis oculi muscle from Orbital rim for the correction of tear trough deformity and palabromalar groove in lower blepharoplasty.Methods 56 cases of lower eye baggy deformity with tear trough deformity and palabromalar groove were treated with the procedure of stripping eye orbicularis oculi muscle from orbital rim by a transcutaneous approach in lower blepharoplasty.The orbital septum was opened along the arcus marginalis for releasing the orbital fat.Some orbital fat was removed if necessary.Then the inferior edge of the orbital septum fat was reset over the orbital rim so as to smooth the infraorbital groove.Results 56 patients were available for 6 to 18 month' s follow-up.54 patients were quite satisfied with the cosmetic result.One developed lower eyelid retraction and another one showed asymmetrical subcutaneous local uneven after 1 month' s.They were all corrected by the second operation after 3 months.Conclusions Stripping orbicularis oculi muscle from orbital rim plays an important role for the correction of tear trough deformity and palabromalar groove in lower blepharoplasty.%目的 探讨伴有明显泪槽和睑颊沟的眼袋整形手术方法.方法 2007年1月至2011年6月,对56例眼袋伴泪槽和睑颊沟畸形者,在术中充分剥离松解弓状缘眼轮匝肌,尤其是附着在内侧泪槽处眶下缘骨膜面的眼轮匝肌,将眶隔脂肪释放重置并缝合固定于眶下缘下方4 ~6 mm处骨膜面上,进行泪槽和睑颊沟充填.结果 术后随访3 ~18个月,54例眼袋消失,无下睑凹陷、不平整等;1例术后1个月出现下睑皮下局部凹凸不平,3个月后经结膜入路修复后改善;1例出现下睑缘轻度退缩,经局部理疗后睑缘退缩消失.结论 剥离松解弓状缘眼轮匝肌,行眶隔重置,对矫正伴有泪槽及睑颊沟畸形的眼袋效果良好.

  11. 面部除皱术中颞浅筋膜瓣转移覆盖眼轮匝肌治疗鱼尾纹%A new procedure to correct the crow's feet by covering the orbicularis oculi muscles with the superficial temporal fascia flap in rhytidectomy

    Institute of Scientific and Technical Information of China (English)

    于丽; 赵作钧; 王佳琦

    2012-01-01

    目的 探讨面部除皱术中应用颞浅筋膜瓣转移覆盖眼轮匝肌治疗鱼尾纹的效果,并对手术操作经验进行总结.方法 在面部除皱术中,颞部处理按常规操作,首先在皮下组织层分离至颞线、眶外缘,然后在帽状腱膜、颞浅筋膜下分离,向前达眶上缘、眶外缘,在帽状腱膜、颞浅筋膜交界处剪开形成颞浅筋膜瓣,将其反转后铺垫于眼外侧的眼轮匝肌表面,用6-0可吸收线适当固定.结果 2004年5月至2010年5月临床治疗18例,术后随访6~12个月,与单纯除皱者相比,本组患者术后鱼尾纹矫正较持久,面部年轻化效果更好,手术效果满意,无局部不平整畸形等并发症出现.结论 除皱术中应用颞浅筋膜瓣转移覆盖眼轮匝肌来治疗鱼尾纹,效果较显著,疗效较传统除皱术更持久.%Objective To explore an ideal procedure with more lasting aesthetic results by covering the orbicularis oculi muscles with the superficial temporal fascia flap in rhytidectomy,which can help to correct the crow' s feet successfully. Methods During rhytidectomy,dissection was performed subcutaneously and also under pericranium and superficial temporal fascia at temporal area. Then the superficial temporal fascia flap was formed by cutting between pericranium and superficial temporal fascia.The fascia flap was reversed to cover the lateral orbicularis oculi muscle with fixation.Results From May 2004 to May 2010,18 cases were treated with a follow-up period of 6-12 months. The crow' s feet was corrected better with long lasting results, compared with conventional rhytidectomy. No complication happened.Conclusions The crow's feet can be corrected markedly with long lasting results by covering the orbicularis oculi muscles with the superficial temporal fascia flap in rhytidectomy.

  12. A Survey of Mercury Concentrations in Soft Tissue of Bivalves Callista umbonella, Saccostrea cucullata and Sediment in the Coastline of Bandar Abbas

    OpenAIRE

    Zahra Bagheri; Alireza Riyahi Bakhtiari

    2014-01-01

    Background and Objectives: The present study was designed to determine total mercury concentrations in sediment and the soft tissues of two bivalve species, Saccostrea cucullata and Callista umbonella, in coastline of Bandar Abbas in 2011. Materials and Methods: Generally, 67 bivalves and 10 sediment samples were collected from two stations (terminal of Bandar Abbas and tourism park of Soro). We measured total mercury concentrations in each sample using Mercury Analyzer (Leco AMA 254). ...

  13. Influence of incubation conditions on the anoxic survival of marine bivalves. Static and semi-static incubations

    OpenAIRE

    Zwaan, A.; Cattani, O; Vitali, G.; Cortesi, P

    2001-01-01

    In a comparative study of 4 bivalve species we show that the apparent widely different tolerances in survival time observed in a closed system filled with N-2-gassed seawater is mainly due to the experimental conditions. Both a high dose of cadmium and the antibiotic chloramphenicol increase survival time 2- to 4-fold. Without precautions for bacterial growth, the survival time of the most tolerant species, Scapharca inaequivalvis, is about 4 times longer than that of the most sensitive speci...

  14. Prevalence and serotyping of Listeria monocytogenes in Portuguese live bivalve molluscs sampled in various steps along the sanitary control process

    OpenAIRE

    Pinto, Ana Luísa; Teixeira, Paula; Castilho, Fernanda; Felício, Maria Teresa; Pombal, Filomena

    2006-01-01

    The prevalence and contamination levels of Listeria monocytogenes were investigated in live bivalve molluscs for human consumption, collected in various steps of the commercial and sanitary circuits in the North of Portugal. Samples of di¡erent species were collected per lot before and after depuration treatment in two depuration units and further, when placed in retail markets. Listeria monocytogenes was isolated from 4% of the samples although with very low contam...

  15. Rapid evolution of sessility in an endemic species flock of the freshwater bivalve Corbicula from ancient lakes on Sulawesi, Indonesia

    OpenAIRE

    von Rintelen, Thomas; Glaubrecht, Matthias

    2005-01-01

    The fauna of ancient lakes frequently contains taxa with highly derived morphologies that resulted from in situ radiation of lacustrine lineages with high antiquity. We employed a molecular mtDNA phylogeny to investigate this claim for corbiculid freshwater bivalves in two ancient lake systems on the Indonesian island Sulawesi. Among the otherwise mobile corbiculid species flock, only one taxon, Posostrea anomioides, in the ancient Lake Poso exhibits a unique habit, i.e. cementing one valve t...

  16. 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.

  17. Abundance not linked to survival across the end-Cretaceous mass extinction: Patterns in North American bivalves

    OpenAIRE

    Lockwood, Rowan

    2003-01-01

    Ecological studies suggest that rare taxa are more likely to go extinct than abundant ones, but the influence of abundance on survivorship in the fossil record has received little attention. An analysis of Late Maastrichtian bivalve subgenera from the North American Coastal Plain found no evidence that survivorship is tied to abundance across the end-Cretaceous mass extinction (65 million years ago), regardless of abundance metric or spatial scale examined. The fact that abundance does not pr...

  18. 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. PMID:27547578

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

    Science.gov (United States)

    Grossman, Ethan L.; O’Dea, Aaron

    2016-01-01

    To examine N-isotope ratios (15N/14N) 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 δ18O values, with open ocean Escudo de Veraguas shells yielding the highest average δ18O (−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 δ15N and δ13C values. Bivalve δ15N and δ13C 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 δ15N and δ13C 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 15N enrichments suggestive of anthropogenic nutrient input, but low δ15N values overall make this interpretation equivocal. Lastly, δ15N 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. PMID:27547578

  20. The influence of temperature and seawater carbonate saturation state on 13C–18O bond ordering in bivalve mollusks

    Directory of Open Access Journals (Sweden)

    R. A. Eagle

    2013-07-01

    Full Text Available The shells of marine mollusks are widely used archives of past climate and ocean chemistry. Whilst the measurement of mollusk δ18O to develop records of past climate change is a commonly used approach, it has proven challenging to develop reliable independent paleothermometers that can be used to deconvolve the contributions of temperature and fluid composition on molluscan oxygen isotope compositions. Here we investigate the temperature dependence of 13C–18O bond abundance, denoted by the measured parameter Δ47, in shell carbonates of bivalve mollusks and assess its potential to be a useful paleothermometer. We report measurements on cultured specimens spanning a range in water temperatures of 5 to 25 °C, and field collected specimens spanning a range of −1 to 29 °C. In addition we investigate the potential influence of carbonate saturation state on bivalve stable isotope compositions by making measurements on both calcitic and aragonitic specimens that have been cultured in seawater that is either supersaturated or undersaturated with respect to aragonite. We find a robust relationship between Δ47 and growth temperature. We also find that the slope of a linear regression through all the Δ47 data for bivalves plotted against seawater temperature is significantly shallower than previously published inorganic and biogenic carbonate calibration studies produced in our laboratory and go on to discuss the possible sources of this difference. We find that changing seawater saturation state does not have significant effect on the Δ47 of bivalve shell carbonate in two taxa that we examined, and we do not observe significant differences between Δ47-temperature relationships between calcitic and aragonitic taxa.

  1. 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.

  2. Combined resection of preseptal fat and partial retro-orbicularis oculus fat : a method for refractory upper eyelid heaviness correction%眶隔前脂肪联合眶上缘上外侧轮匝肌深面脂肪部分切除矫正上睑臃肿

    Institute of Scientific and Technical Information of China (English)

    金云波; 林晓曦; 陈辉; 胡晓洁; 马刚; 常雷; 仇雅璟; 杨希; 王天佑

    2014-01-01

    Objective To investigate anoperative method of combined resection of preseptal fat and partial retro-orbicularis oculus fat (ROOF) for correction of upper eyelid heaviness,and evaluate the efficacy and safety of the method.Methods Preseptal fat lies widely under the orbicularis oculi in the upper eyelid,and retro-orbicularis oculus fat (ROOF) lies in the lateral supraorbital area.Combined resection of preseptal fat and partial ROOF was performed in patients selected by examination.The efficacy and safety were evaluated by follow-up study.Results From May 2011 to July 2013,38 selected patients received the treatment with 3 months to 28 months follow up.The heaviness of upper eyelid improved in all cases.One patient developed postoperative hematoma,and another patient had a transient numbness over the lateral upper brow region.37 patients were satisfied with the result.Conclusions Combined resection of preseptal fat and partial ROOF was effective in reducing the heaviness of upper eyelid,without major complications.The operative method should be an important adjunct for selected patients undergoing blepharoplasty.%目的 探讨眶隔前脂肪联合眶上缘上外侧轮匝肌深面脂肪(retro-orbicularis oculusfat,ROOF)部分切除,矫正上睑臃肿的疗效和安全性.方法 眶隔前脂肪位于上睑眼轮匝肌深面,ROOF位于眶上缘上外侧轮匝肌深面,与眶隔前脂肪相延续.对术前评估为眶隔前脂肪和ROOF肥厚的病例,实施眶隔前脂肪联合ROOF部分切除术,并随访评价其疗效和安全性.结果 2011年5月至2013年7月,对38例患者实施该术式,术后随访3~ 28个月,平均8.6个月,所有患者上睑臃肿改善;1例术后出现血肿,10d自行完全吸收;1例患者眉外侧上方区域局部麻木,2个月后完全恢复.37例患者对手术效果满意.结论 眶隔前脂肪联合ROOF部分切除可有效改善上睑臃肿,并发症轻微,满意度高,可作为上睑整形手术的重要补充.

  3. 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

  4. A comparative study on effects of heterotrophic microbial activity on the stability of bivalve and coral carbonate during early diagenesis.

    Science.gov (United States)

    Lange, Skadi M.; Krause, Stefan; Immenhauser, Adrian; Ritter, Ann-Christin; Gorb, Stanislav N.; Kleinteich, Thomas; Treude, Tina

    2016-04-01

    Following deposition and shallow burial, marine biogenic carbonates are exposed to an environment that is geochemically affected by a manifold of bacterial metabolic redox processes. To allow for comparison of potential microbe-mediated alteration effects on carbonates, we used aragonitic bivalve shell samples and porous aragonitic coral fragments for incubation experiments in oxic- and anoxic seawater media. The media contained marine sediment slurries or bacterial cultures to mimic the natural processes in vitro. The results for anoxic experimental media containing bivalve shell samples or coral fragments displayed considerable changes in carbonate-system parameters (pH, AT, CA, DIC) and divalent-cation ratios (Mg/Ca, Mg/Sr, Sr/Ca) over time. Furthermore, incubated bivalve shell samples were altered in morphology, elemental composition and isotopic signature. Coral-fragment bearing oxic incubations were run at two temperature regimes and divalent-cation ratios of the high-temperature bacterial medium displayed withdrawal of Ca2+ and Sr2+ from the medium, thus indicating microbe-induced secondary aragonite precipitation. Analyses of coral fragments include electron-microprobe mapping and X-ray microtomography to resolve elemental sample composition and pore-space alteration features, respectively. Up to this point our results indicate that heterotrophic bacterial activity has the potential to affect surficial or open pore space in carbonate archives by increasing rates of alteration relative to sterile environments.

  5. [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. PMID:25102639

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. Bivalve molluscs as vectors of marine biotoxins involved in seafood poisoning.

    Science.gov (United States)

    Ciminiello, P; Fattorusso, E

    2006-01-01

    Molluscs of many sorts, which are high in protein and trace minerals, have always been a substantial portion of the human diet. A great variety of mollusc species are therefore of commercial importance throughout the world. Episodes of poisoning occasionally happen to the consumers of molluscs, the main hazard being represented by bivalve molluscs. These organisms are filter-feeders, feeding mainly on a wide range of phytoplankton species. Among the thousands of species of microscopic algae at the base of the marine food chain, there are a few dozen which produce potent toxins. One major category of impact occurs when toxic phytoplankton are filtered from the water as food by shellfish, which then accumulate the algal toxins to levels which can be lethal to humans. Incidences of poisoning related to marine algal toxins come under the main categories of paralytic shellfish poisoning (PSP), neurotoxic shellfish poisoning (NSP), diarrhetic shellfish poisoning (DSP), and amnesic shellfish poisoning (ASP), depending upon the toxins and the symptoms that they cause. Since the beginning of the 1990s, a research program has been initiated to examine the toxin profiles in mussels from the Adriatic Sea. Since then, a number of polyether toxins have been isolated and characterized, some of which represent new additions to the DSP class of biotoxins. During this investigation, new types of toxins have also been isolated. The recent application of LC-MS methods for the detection of Adriatic marine biotoxins made it possible to speed up the analysis of toxic samples.

  14. Protandric hermaphroditism in the whale-fall bivalve mollusc Idas washingtonia

    Science.gov (United States)

    Tyler, Paul A.; Marsh, Leigh; Baco-Taylor, Amy; Smith, Craig R.

    2009-09-01

    Whale falls provide abundant but relatively ephemeral, sulphide-rich habitat islands on the deep-sea floor. To explore life-history adaptations to whale-fall habitats, we examined the reproductive biology of Idas washingtonia, a bathymodiolin mussel occurring in abundance on sunken whale skeletons in the deep northeast Pacific Ocean. Analysis of the reproductive biology of I. washingtonia demonstrates strong evidence of protandric hermaphroditism. Developing males were recognised in individuals as small as 1.7 mm shell length and spermatogenesis continued until ˜7 mm length. At >6.5 mm, males were generally spent and the first previtellogenic oocytes were observed. Although developing females were found as small as 4.5 mm shell length, most well-developed females were >6 mm shell length. Overall, females only formed ˜12% of the population. As with other modiolid bivalves, fecundity was high and the egg size whale falls even though these may have been severely reduced in abundance since the peak of commercial whaling activity in the 20th century.

  15. 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.

  16. 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.

  17. Bioremediation of metal-rich effluents: could the invasive bivalve work as a biofilter?

    Science.gov (United States)

    Rosa, Inês Correia; Costa, Raquel; Gonçalves, Fernando; Pereira, Joana Luísa

    2014-09-01

    Industrial effluents are important sources of contamination of water and sediments, frequently causing serious damage at different levels of biological organization. Management and treatment of harmful industrial wastes is thus a major concern. Metal-bearing effluents, such as acid mine drainage (AMD), are particularly problematic because metals can easily bioaccumulate in organisms and biomagnify across the trophic chain. Several solutions have been proposed to treat AMD, including active methods involving the addition of neutralizing agents and passive techniques that use natural energy sources for remediation. However, increasing environmental and economic requirements lead the constant search for more sustainable solutions. The present study explores the possibility of using , an invasive freshwater bivalve, as a bioremediation tool using AMD as a model, metal-bearing effluent. The study compares untreated and biotreated effluents at two dilution levels (4 and 10% v/v) following two distinct approaches: (i) chemical characterization of the metal concentrations in water complemented by determination of the accumulation in the clams' soft tissues and shells; and (ii) ecotoxicity assessment using standard organisms (the bacterium , the microalgae , and the cladoceran ). Significant removal of metals from water was recorded for both effluent dilutions, with higher purification levels found for the 4% effluent. The environmental toxicity of the effluents generally decreased after the treatment with the clams. Thus, this study provides evidence for the suitability of as a bioremediator for metal-bearing effluents, especially if the treatment can be materialized in a multistage configuration system. PMID:25603239

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

    Science.gov (United States)

    Jackson, Jennifer A; Linse, Katrin; Whittle, Rowan; Griffiths, Huw J

    2015-01-01

    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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. The packaging problem: bivalve prey selection and prey entry techniques of the octopus Enteroctopus dofleini.

    Science.gov (United States)

    Anderson, Roland C; Mather, Jennifer A

    2007-08-01

    Many predators face a complex step of prey preparation before consumption. Octopuses faced with bivalve prey use several techniques to penetrate the shells to gain access to the meat inside. When given prey of mussels Mytilus trossulus, Manila clams Venerupis philippinarum, and littleneck clams Protothaca staminea, Enteroctopus dofleini solved the problem differently. They pulled apart V. philippinarum and M. trossulus, which had the thinnest shells and the least pulling resistance. P. staminea were eaten after the shells had been chipped or had been penetrated by drilling, presumably to inject a toxin. Likely because of these differences, octopuses consumed more V. philippinarum and M. trossulus than P. staminea when the mollusks were given to them either 1 species at a time or all together. However, when the shells were separated and the penetration problem removed, the octopuses predominantly chose P. staminea and nearly ignored M. trossulus. When V. philippinarum were wired shut, octopuses switched techniques. These results emphasize that octopuses can learn on the basis of nonvisual information and monitor their body position to carry out feeding actions. PMID:17696656

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

    Directory of Open Access Journals (Sweden)

    J R Shipway

    Full Text Available 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.

  8. Commensal associations and benthic habitats shape macroevolution of the bivalve clade Galeommatoidea.

    Science.gov (United States)

    Li, Jingchun; Ó Foighil, Diarmaid; Strong, Ellen E

    2016-07-13

    The great diversity of marine life has been shaped by the interplay between abiotic and biotic factors. Among different biotic interactions, symbiosis is an important yet less studied phenomenon. Here, we tested how symbiotic associations affected marine diversification, using the bivalve superfamily Galeommatoidea as a study system. This superfamily contains large numbers of obligate commensal as well as free-living species and is therefore amenable to comparative approaches. We constructed a global molecular phylogeny of Galeommatoidea and compared macroevolutionary patterns between free-living and commensal lineages. Our analyses inferred that commensalism/sediment-dwelling is likely to be the ancestral condition of Galeommatoidea and that secondary invasions of hard-bottom habitats linked to the loss of commensalism. One major clade containing most of the free-living species exhibits a 2-4 times higher diversification rate than that of the commensals, likely driven by frequent niche partitioning in highly heterogeneous hard-bottom habitats. However, commensal clades show much higher within-clade morphological disparity, likely promoted by their intimate associations with diverse hosts. Our study highlights the importance of interactions between different ecological factors in shaping marine macroevolution and that biotic factors cannot be ignored if we wish to fully understand processes that generate marine biodiversity. PMID:27383818

  9. 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.

  10. 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. PMID:27285613

  11. 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.

  12. 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

  13. 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.

  14. 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

  15. 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

  16. 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

  17. Metal, mutagenicity, and biochemical studies on bivalve molluscs from Spanish coasts

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Ariza, A.; Abril, N.; Navas, J.I.; Dorado, G.; Lopez-Barea, J.; Pueyo, C. (Departmento de Genetica, Facultad de Ciencias, Universidad de Cordoba, (Spain))

    1992-01-01

    Three species of marine bivalve molluscs (Chamelea gallina, Ruditapes decussatus, and Crassostrea gigas) have been studied in order to evaluate the levels of pollution on the South Atlantic Spanish littoral. Several transition metals (Cu, As, Cd, Sn, Hg, Pb) were determined as a general index of total contamination. Animals from putative contaminated areas exhibited higher metal contents than those from cleaner waters. C. gigas showed 5-20-fold higher total metal content than the other two species. The mutagenicity of ethanolic extracts was assayed by using both the His reversion and the Ara forward mutation tests. Mollusc tissues from the three species did not contain genotoxins active on TA98 (frameshift mutations) or TA100 (mainly G:C base-pair substitutions), but did contain direct-acting genotoxins of a polar nature and oxidative type. This was based on the following observations: (1) mammalian metabolic activation was not required for mutagenicity, (2) mutagens were eluted with the polar fraction from XAD-2 columns, and (3) mutagenic responses were observed with Salmonella typhimurium TA102 (base-pair substitutions; sensitive to oxidative damages) and Escherichia coli catalase-deficient (AraR forward mutations) strains. No relevant differences were found in the mutagenicity of mollusc extracts from areas with different pollution levels. Otherwise, our data suggest that, in general, animals living in contaminated environments had fewer genotoxins of oxidative type than those from less polluted areas. Such a result might be explained by the observation of increased levels of a number of detoxifying and antioxidant enzymes, such as glutathione-S-transferase, glutathione-peroxidase, catalase, and superoxide dismutase.

  18. 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

  19. Location is everything: evaluating the effects of terrestrial and marine resource subsidies on an estuarine bivalve.

    Science.gov (United States)

    Harding, Joel M S; Segal, Michelle R; Reynolds, John D

    2015-01-01

    Estuaries are amongst the world's most productive ecosystems, lying at the intersection between terrestrial and marine environments. They receive substantial inputs from adjacent landscapes but the importance of resource subsidies is not well understood. Here, we test hypotheses for the effects of both terrestrial- and salmon-derived resource subsidies on the diet (inferred from stable isotopes of muscle tissue), size and percent nitrogen of the soft-shell clam (Mya arenaria), a sedentary estuarine consumer. We examine how these relationships shift across natural gradients among 14 estuaries that vary in upstream watershed size and salmon density on the central coast of British Columbia, Canada. We also test how assimilation and response to subsidies vary at smaller spatial scales within estuaries. The depletion and enrichment of stable isotope ratios in soft-shell clam muscle tissue correlated with increasing upstream watershed size and salmon density, respectively. The effects of terrestrial- and salmon-derived subsidies were also strongest at locations near stream outlets. When we controlled for age of individual clams, there were larger individuals with higher percent nitrogen content in estuaries below larger watersheds, though this effect was limited to the depositional zones below river mouths. Pink salmon exhibited a stronger effect on isotope ratios of clams than chum salmon, which could reflect increased habitat overlap as spawning pink salmon concentrate in lower stream reaches, closer to intertidal clam beds. However, there were smaller clams in estuaries that had higher upstream pink salmon densities, possibly due to differences in habitat requirements. Our study highlights the importance of upstream resource subsidies to this bivalve species, but that individual responses to subsidies can vary at smaller scales within estuaries. PMID:25993002

  20. Location is everything: evaluating the effects of terrestrial and marine resource subsidies on an estuarine bivalve.

    Directory of Open Access Journals (Sweden)

    Joel M S Harding

    Full Text Available Estuaries are amongst the world's most productive ecosystems, lying at the intersection between terrestrial and marine environments. They receive substantial inputs from adjacent landscapes but the importance of resource subsidies is not well understood. Here, we test hypotheses for the effects of both terrestrial- and salmon-derived resource subsidies on the diet (inferred from stable isotopes of muscle tissue, size and percent nitrogen of the soft-shell clam (Mya arenaria, a sedentary estuarine consumer. We examine how these relationships shift across natural gradients among 14 estuaries that vary in upstream watershed size and salmon density on the central coast of British Columbia, Canada. We also test how assimilation and response to subsidies vary at smaller spatial scales within estuaries. The depletion and enrichment of stable isotope ratios in soft-shell clam muscle tissue correlated with increasing upstream watershed size and salmon density, respectively. The effects of terrestrial- and salmon-derived subsidies were also strongest at locations near stream outlets. When we controlled for age of individual clams, there were larger individuals with higher percent nitrogen content in estuaries below larger watersheds, though this effect was limited to the depositional zones below river mouths. Pink salmon exhibited a stronger effect on isotope ratios of clams than chum salmon, which could reflect increased habitat overlap as spawning pink salmon concentrate in lower stream reaches, closer to intertidal clam beds. However, there were smaller clams in estuaries that had higher upstream pink salmon densities, possibly due to differences in habitat requirements. Our study highlights the importance of upstream resource subsidies to this bivalve species, but that individual responses to subsidies can vary at smaller scales within estuaries.

  1. The effect of immersion time on burying depth of the bivalve Macoma balthica (Tellinidae)

    Science.gov (United States)

    de Goeij, Petra; Honkoop, Pieter J. C.

    2002-03-01

    As a characteristic buried tellinid bivalve, Macoma balthica has a long inhalent siphon that enables it to feed in two different ways: deposit and suspension feeding. To deposit feed efficiently on benthic microalgae, Macoma has to live close to the sediment surface, where it can graze an extensive surface area, but is within reach of many predators. Individuals that are more safely buried at a greater depth can only suspension feed, or deposit feed from a small surface area. We expected local differences in burying depth on intertidal mudflats to be caused by differences in immersion time (i.e. time available for feeding, particularly suspension feeding), since immersion time has been shown experimentally to affect body condition positively, and since body condition and burying depth in Macoma are postively related in the field. To test this we experimentally manipulated immersion time, and followed changes in burying depth and body condition. In the experiments, longer immersion time went consistently with greater burying depth of Macoma and higher body condition. On a transect in the western Wadden Sea, the deepest Macoma were indeed found at the intertidal level with the longest immersion time, but these were at that time not the animals with the highest body condition. Within each locality, however, body condition was positively correlated with burying depth. The experimental data and the within-locality data support the hypothesis that longer immersion time may influence burying depth through body condition. However, the fact that between-locality differences in burying depth seemed to be consistently related to immersion time, but not to body condition, indicates that body condition alone does not explain place-to-place variation in burying depth.

  2. 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.

  3. Genetic connectivity between north and south Mid-Atlantic Ridge chemosynthetic bivalves and their symbionts.

    Directory of Open Access Journals (Sweden)

    Karina van der Heijden

    Full Text Available Transform faults are geological structures that interrupt the continuity of mid-ocean ridges and can act as dispersal barriers for hydrothermal vent organisms. In the equatorial Atlantic Ocean, it has been hypothesized that long transform faults impede gene flow between the northern and the southern Mid-Atlantic Ridge (MAR and disconnect a northern from a southern biogeographic province. To test if there is a barrier effect in the equatorial Atlantic, we examined phylogenetic relationships of chemosynthetic bivalves and their bacterial symbionts from the recently discovered southern MAR hydrothermal vents at 5°S and 9°S. We examined Bathymodiolus spp. mussels and Abyssogena southwardae clams using the mitochondrial cytochrome c oxidase subunit I (COI gene as a phylogenetic marker for the hosts and the bacterial 16S rRNA gene as a marker for the symbionts. Bathymodiolus spp. from the two southern sites were genetically divergent from the northern MAR species B. azoricus and B. puteoserpentis but all four host lineages form a monophyletic group indicating that they radiated after divergence from their northern Atlantic sister group, the B. boomerang species complex. This suggests dispersal of Bathymodiolus species from north to south across the equatorial belt. 16S rRNA genealogies of chemoautotrophic and methanotrophic symbionts of Bathymodiolus spp. were inconsistent and did not match the host COI genealogy indicating disconnected biogeography patterns. The vesicomyid clam Abyssogena southwardae from 5°S shared an identical COI haplotype with A. southwardae from the Logatchev vent field on the northern MAR and their symbionts shared identical 16S phylotypes, suggesting gene flow across the Equator. Our results indicate genetic connectivity between the northern and southern MAR and suggest that a strict dispersal barrier does not exist.

  4. In situ exposure history modulates the molecular responses to carbamate fungicide Tattoo in bivalve mollusk.

    Science.gov (United States)

    Falfushynska, Halina I; Gnatyshyna, Lesya L; Stoliar, Oksana B

    2013-04-01

    The aim of the present study was the investigation of the effect of in situ exposure history on the responses of freshwater mussels to thiocarbamate fungicide. Male bivalve mollusks Anodonta anatina (Unionidae) from polluted (A) and unpolluted (F) sites were subjected to 14 days of exposure to fungicide Tattoo (mixture of propamocarb and mancozeb, 91 μg L(-1)). When unexposed mussels were compared, chronic effect of toxic environment in site A was confirmed by oxidative stress indices (high levels of superoxide dismutase and catalase activities, lipid peroxidation, protein carbonyls and oxyradical production, low level of total glutathione (GSH)), genotoxicity (high levels of DNA-strand breaks and caspase-3 activity in digestive gland), and cytotoxicity (low lysosomal membrane stability in hemocytes), elevated vitellogenin-like proteins (Vtg-LP) concentration in gonads, high levels of Cu, Zn, Cd, metallothionein (MT)-bound metals (MT-Me) and MT-related thiol (MT-SH), and low ethoxyresorufin-O-deethylase (EROD) activity in digestive gland. The major differences in the responses of the two exposed groups were related to antioxidant defense and MT: in the group A, prominent oxidative stress response with the participation of MT-SH and GSH in the gills, EROD activation, but decrease of MT-Me level was shown, whereas in group F exposure provoked the elevation of MT-Me, caspase-3 and Vtg-LP values. Carbamate did not cause cholinesterase depletion and cytotoxicity. However, genotoxic and pro-oxidant effects (increased levels of hemocytes with micronuclei and nuclear abnormalities, DNA-strand breaks and oxyradical in digestive gland), were common responses for both the exposed groups. PMID:23306937

  5. 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

  6. Assessment of Bivalves as potential bioindicator of heavy metal pollution along Ghana's coast using Instrumental Neutron Activation Analysis

    International Nuclear Information System (INIS)

    The assessment of environmental metal pollution along the coast of Ghana was investigated by analysing the heavy and trace metals in the soft body tissue and shells of two abundant bivalve molluses Donax pulchelus, the brown mussel Perna perna and the sediment in which they live at three different sampling locations (Accra, Cape Coast and Axim). Potentially toxic or toxic metals analysed in this study were Al, As, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, Sc, V, Zn using the analytical technique instrumental Neutron Activation Analysis (INAA) in the quantitative determination of the heavy metals. Marine sediment reference material (Estuarine Sediment SRM 1646a) and Peach leaves SRM 1547 provided the certified reference in the quality assurance control. The concentration found in the potentially toxic heavy metals (As, Cd, Co, Cu, Hg, Ni,and Zn) all recorded lower than the maximum acceptable limits in the bivalve molluscs designated for human consumption, fluctuating between blow detection limit <0.03 to 180.38μ/g. The other elements (Al, Ca, Fe, K, Mg, Mn and Na) recorded a high concentration in both Donax pulchelus and Perna perna (4.54μ/g to 565.13μ/g) in all the sampling location.The minor elements (V and Sc) recorded between 0.05 μ/g to 5.68μ/g. The data on the concentration of the bivalve mollusc also showed lower values compared with other regions of the world. The physicochemical parameters determined were generally supportive of aquatic life providing the necessary conditions. (au)

  7. 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

  8. The influence of sedimentation on metal accumulation and cellular oxidative stress markers in the Antarctic bivalve Laternula elliptica

    Science.gov (United States)

    Husmann, G.; Abele, D.; Monien, D.; Monien, P.; Kriews, M.; Philipp, E. E. R.

    2012-10-01

    Recent rapid climate warming at the western Antarctic Peninsula (WAP) results in elevated glacial melting, enhanced sedimentary run-off, increased turbidity and impact of ice-scouring in shallow coastal areas. Discharge of mineral suspension from volcanic bedrock ablation and chronic physical disturbance is expected to influence sessile filter feeders such as the Antarctic soft shell clam Laternula elliptica (King and Broderip, 1832). We investigated effects of sedimentary run-off on the accumulation of trace metals, and together with physical disturbance, the cumulative effect on oxidative stress parameters in younger and older L. elliptica from two stations in Potter Cove (King George Island, Antarctica) which are distinctly impacted by turbidity and ice-scouring. Fe, Mn, Sr, V and Zn concentrations were slightly higher in sediments of the station receiving more sediment run-off, but not enriched in bivalves of this station. The only element that increased in bivalves experimentally exposed to sediment suspension for 28 days was Mn. Concentration of the waste accumulation biomarker lipofuscin in nervous tissue was higher in L. elliptica from the “exposed” compared to the “less exposed” site, whereas protein carbonyl levels in bivalve mantle tissue were higher at the less sediment impacted site. Tissue metal content and lipofuscin in nervous tissue were generally higher in older compared to younger individuals from both field stations. We conclude that elevated sediment ablation does not per se result in higher metal accumulation in L. elliptica. Instead of direct absorbance from sediment particles, metal accumulation in gills seems to indicate uptake of compounds dissolved in the water column, whereas metals in digestive gland appear to originate from enriched planktonic or detritic food. Accumulation of cellular waste products and potentially reactive metals over lifetime presumably alters L. elliptica physiological performance with age and may

  9. Detection of viruses and virus-like particles in four species of wild and farmed bivalve molluscs in Alaska, U.S.A., from 1987 to 2009.

    Science.gov (United States)

    Meyers, Theodore R; Burton, Tamara; Evans, Wally; Starkey, Norman

    2009-12-22

    The U.S. Alaska Department of Fish and Game has regulatory oversight of the mariculture industry that is partially administered through a statewide shellfish health policy. Possession and transport of bivalve molluscs require development of indigenous pathogen histories from diagnostic examinations of wild and farmed populations. These examinations have resulted in the detection of various infectious agents and parasites including viruses: an aquareovirus and aquabirna-like virus isolated by fish cell culture, and papilloma- or polyoma- and herpes-like virus particles within bivalve cell intranuclear inclusion bodies observed by electron microscopy. This study summarizes these results in samples examined from 1987 to 2009 and is the first description of poikilothermic viruses from Alaskan waters isolated from or observed within the tissues of 4 species of bivalve molluscs: geoduck clam Panope abrupta, native littleneck clam Protothaca staminea, purple-hinged rock scallop Crassadoma gigantea and Pacific oyster Crassostrea gigas. PMID:20183960

  10. 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.

  11. Assimilation efficiencies and turnover rates of trace elements in marine bivalves: A comparison of oysters, clams and mussels

    Science.gov (United States)

    Reinfelder, J.R.; Wang, W.-X.; Luoma, S. N.; Fisher, N.S.

    1997-01-01

    Assimilation efficiencies (AEs) and physiological turnover-rate constants (k) of six trace elements (Ag, Am, Cd, Co, Se, Zn) in four marine bivalves (Crassostrea virginica Gmelin,Macoma balthica Linnaeus, Mercenaria mercenaria Linnaeus, and Mytilus edulis Linnaeus) were measured in radiotracer-depuration experiments. Egestion rates of unassimilated elements were highest during the first 24 h of depuration and declined thereafter. Significant egestion of unassimilated Co, however, continued for up to 5 d in Macoma balthica,Mercenaria mercenaria and Mytilus edulis. With the exception of the extremely low values for110 mAg, 109Cd, and 65Zn in C. virginica, physiological turnover-rate constants (k) showed no general pattern of variation among elements, bivalve species or food types, and were relatively invariant. Values from  ≤0.001 to 0.1 d−1 were observed, but excluding those for Co, most values were  ≤0.04 d−1. In all four species, the AEs of Ag, Am, and Co were generally lower than those of Cd, Se, and Zn. The AEs of Ag, Cd, Se, and Zn in these bivalves are directly related to the proportion of each element in the cytoplasmic fraction of ingested phytoplankton, indicating that >80% of elements in a prey alga's cytoplasm was assimilated. C. virginica, Macoma balthica, and Mercenaria mercenaria assimilated ∼36% of the Ag and Cd associated with the non-cytoplasmic (membrane/organelle) fraction of ingested cells in addition to the cytoplasmic fraction. The ratio of AE:k, which is proportional to the consumer–prey trace-element bioaccumulation factor (concentration in consumer:concentration in prey) was generally greater for Cd, Se, and Zn than for Ag, Am, and Co. This ratio was lowest in Mytilus edulis, suggesting that this bivalve, the most widely employed organism in global biomonitoring, is relatively inefficient at accumulating important elements such as Ag, Cd, and Zn from ingested phytoplankton.

  12. 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

  13. Implementação da norma NP EN ISO 22000:2005 em centros de depuração de bivalves: estudo de caso

    OpenAIRE

    Jesus, Luci Catarina Agostinho

    2016-01-01

    Dissertação de Mestrado, Tecnologia dos Alimentos, Instituto Superior de Engenharia, Universidade do Algarve, 2016 Os bivalves, são importantes em termos socio-económicos e na gastronomia portuguesa, e são abundantes na Ria Formosa e costa Algarvia adjacente. De entre os bivalves, a amêijoa-boa (Ruditapes decussatus) é uma espécie com elevado interesse económico que é muito consumida pelo mundo fora, mas particularmente nos países do sul da Europa. Considerando as condições amb...

  14. Late Devonian (Frasnian) bivalves from the Nocedo Formation: the results of Wilhelm Kegel’s 1927 field trip to northern Spain

    OpenAIRE

    Amler, M.R.W.

    2010-01-01

    During a field trip to the Peña-Corada Unit of the southernmost Esla region of the Cantabrian Mountains in 1927, the German stratigrapher Wilhelm Kegel sampled brachiopods and bivalves from a section in the Laoz valley near La Ercina. The stratigraphic position is believed to be part of the Nocedo Formation of Frasnian age. This fauna includes poorly preserved steinkerns of a near-shore bivalve fauna that was prepared for publication including labels and proposed names, but never published. T...

  15. 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...... was estimated by combining field measurements of clearance rates and modelling of the bivalve bed (topography, biomass distribution, temporal and spatial water coverage and depth). The average density of C. gigas and M. edulis was 35 ± 36 and 1001 ± 685 ind. m−2, respectively. The water volume cleared during...

  16. Study on blepharoplasty stripping arcuate margin of orbicularis oculi muscle used in patients with tear trough and palpbromalar groove%应用剥离弓状缘眼轮匝肌整复伴有泪槽和睑颊沟的眼袋疗效观察

    Institute of Scientific and Technical Information of China (English)

    蒋学金

    2014-01-01

    Objective To explore divest arcuate edge orbicularis muscle surgery reconstructive treatment of the symptoms of clinical efficacy and recovery.Methods 80 patients with tear trough and palphromalar groove pouch,according to the operation method,were divided into group A and group B.The patients received stripped arcuate margin of orbicularis oculi muscle operation and true orbital fat too much fat operation,operation treatment,respectively.The satisfaction and revisit the rebound rate of the two groups after surgery were compared.Results Of 40 patients in A group,37 cases (92.5%)were satisfied with the treatment,general satisfaction in 3 cases (7.5%),0 case (0.0%) was not satisfactory.In B group,28 cases (62.5%)were satisfied with the treatment,general satisfaction in 9 cases (22.5%),3 cases (15.0%)were not satisfactory.The clinical efficacy between the two groups was significantly different(Z =18.481,P < 0.01).During follow-up,in A group,one case (2.5%)relapsed.In B group,7 cases (17.5%) relapsed after 2 years.The postoperative recurrence rate between the two groups had significant difference (Z =7.314,P < 0.05).Conclusion For patients with tear trough and palpbromalar groove pouch,treatment by stripping arcuate margin of orbicularis oculi muscle operation method can effectively correct the tear trough and palabromalar groove deformity postoperative reduction performance,has high degree of satisfaction,the recurrence rate is low,the clinical effect is significant,it is worthy of further clinical application and research.%目的 探讨剥离弓状缘眼轮匝肌手术整复伴有泪槽和睑颊沟的眼袋临床效果.方法 对80例伴有泪槽和睑颊沟的眼袋患者,按照手术方法不同分为A组与B组各40例,分别进行剥离弓状缘眼轮匝肌手术与真性眶内脂肪过多去脂手术,进行整复治疗,对比分析两组患者的手术后整复满意度以及回访复发率.结果 治疗后,A组满意37例(92.5

  17. 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.

  18. Joint use of multiple Synthetic Aperture Radar imagery for the detection of bivalve beds and morphological changes on intertidal flats

    Science.gov (United States)

    Gade, Martin; Melchionna, Sabrina

    2016-03-01

    We analyzed 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.

  19. 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.

  20. Uptake and loss of 134Cs and 60Co by the Baltic bivalve Macoma Baltica under laboratory conditions

    International Nuclear Information System (INIS)

    In order to predict the radiological impact on man via harvestable sea food products, it is essential to make a critical evaluation of the transfer routes and the rates on which radionuclides are transferred through the aquatic food chains. In the Baltic, the bivalve Macoma Baltica comprises a main food item for fish species of commercial interest, such as flounder. The accumulation and release of Cs-134 and Co-60 by Macoma was experimentally investigated. The nuclides were added to the water and the activity content of the bivalves was determined at regular intervals. The uptake was quite rapid, 40 per cent (Cs) and 55 per cent (Co) respectively of the final steady state was obtained after 24 hours. The subsequent release was rapid as well, 50 per cent (Cs) and 40 per cent (Co) respectively of the accumulated activity was lost within 6 days. The experiments demonstrated that the major intake route following short-term releases of activity will be from the water column. The close connection between activity in water and organism can thus be used for predictive purposes without the complication of radionuclide uptake from contaminated sediments. (Author)

  1. 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.

  2. Effect of cage design on growth of transplanted Asian clams: implications for assessing bivalve responses in streams.

    Science.gov (United States)

    Hull, Matthew S; Cherry, Donald S; Merricks, Timothy C

    2004-01-01

    This study was designed to determine whether survivorship and growth of Asian clams (Corbicula fluminea [Müller]) differed significantly between two types of field enclosures. Enclosures were either flexible mesh bags or rigid cages (hereto after referred as bioboxes) designed to homogenize substrate among study sites and accommodate Asian clam feeding mechanisms. For 96d, cages remained at 12 Clinch River (CR), Hurricane Fork (HF), and Dump's Creek (DC) sites upstream and downstream of a coal-fired power plant discharge, coal mining effluent, and coal combustion-related disposal facilities in Carbo, Virginia. Although survivorship was not significantly different between cage types, mean growth of clams in bioboxes was significantly greater overall (p = 0.0157). Despite the difference in growth between the two cage types, both confirmed significant reductions of survivorship and growth directly below the power plant discharge. Additionally, coefficient of variance values for biobox growth data were reduced at most study sites (averages of 16% for bioboxes versus 19% for mesh bags). Our results have implications toward strengthening weight-of-evidence approaches used to link impairment of transplanted bivalves to environmental contaminants. More importantly, these results suggest that ecotoxicological impairment of bivalves transplanted downstream of the coal-fired power plant discharge functioned independently of site-specific substrate provisions. PMID:15327146

  3. Composition and distribution of bivalves of the abyssal plain adjacent to the Kuril-Kamchatka Trench (Pacific Ocean)

    Science.gov (United States)

    Kamenev, Gennady M.

    2015-01-01

    The KuramBio German-Russian deep-sea expedition ("Sonne", 2012) revealed a rich fauna of bivalves (55 species belonging to 21 families) on the abyssal plain (4861-5787 m) adjacent to the Kuril-Kamchatka Trench. Per station species richness varied from 18 to 33 species. The richest families were Cuspidariidae (7 species), Tindariidae (6 species), Thyasiridae (6 species), and Xylophagidae (5 species). The families Nuculidae, Malletidae, Yoldiidae, Mytilidae, Protocuspidariidae, and Verticordiidae were represented by a single species. Representatives of the family Siliculidae were recorded in the northwestern Pacific for the first time. Thirteen species (23.6%) were most common in the investigated northwestern Pacific region. Nine species (16.4%) were only found at one of the stations. Eight species (14.5%) are first records for the northwestern Pacific, of which Yoldiella cf. jeffreysi (Hidalgo, 1877), Pristigloma cf. albaSanders and Allen, 1973, and Syssitomya cf. pourtalesianaOliver, 2012 were previously known only for the Atlantic Ocean. The high diversity and richness of the bivalve fauna on the abyssal plain in the Kuril-Kamchatka Trench area may be connected to the favorable feeding conditions in this, one of the most highly productive areas of the Pacific Ocean.

  4. 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

  5. Influence of the level of oxygenation in sediment and water on copper bioavailability to marine bivalves: Laboratory experiments and translocation experiments in the field

    NARCIS (Netherlands)

    Hummel, H.; Magni, P.; Amiard-Triquet, C.; Rainglet, F.; Modderman, R.; Van Duijn, Y.; Herssevoort, M.; De Jong, J.H.; Snitsevorg, L.; Ytsma, M.; Bogaards, R.H.; De Wolf, L.

    1998-01-01

    The effects of differences in the level of oxygenation of sediment or water on the condition and copper content of two bivalves, the Baltic clam Macoma balthica and the cockle Cerastoderma edule, were assessed. Specimens from four intertidal flats in the Netherlands and France were compared, translo

  6. Genetic aspects of restoring Olympia oysters and other native bivalves: Balancing the need for action, good intentions, and the risks of making things worse

    Science.gov (United States)

    As interest and efforts in ecological restoration of native bivalve populations grow, the genetic implications of various restoration strategies are often unclear to resource managers and restoration practitioners, even though genetic considerations are vital to the ultimate success or failure of re...

  7. Late Devonian (Frasnian) bivalves from the Nocedo Formation: the results of Wilhelm Kegel’s 1927 field trip to northern Spain

    NARCIS (Netherlands)

    Amler, M.R.W.

    2010-01-01

    During a field trip to the Peña-Corada Unit of the southernmost Esla region of the Cantabrian Mountains in 1927, the German stratigrapher Wilhelm Kegel sampled brachiopods and bivalves from a section in the Laoz valley near La Ercina. The stratigraphic position is believed to be part of the Nocedo F

  8. 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.

  9. 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.

  10. Evaluation of the threat of marine CO2 leakage-associated acidification on the toxicity of sediment metals to juvenile bivalves

    International Nuclear Information System (INIS)

    Highlights: • Short-term tests using juveniles of bivalves to study the effects of CO2 dissolved. • CO2 causes effects if the threshold concentration of the organism is overlapped. • Flows of escaped CO2 would affect the geochemical composition of sediment–seawater. • CO2-induced acidification would affect differently to marine sediment toxicity. - Abstract: The effects of the acidification associated with CO2 leakage from sub-seabed geological storage was studied by the evaluation of the short-term effects of CO2-induced acidification on juveniles of the bivalve Ruditapes philippinarum. Laboratory scale experiments were performed using a CO2-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 pCO2 and the dissolved metal concentrations (Zn and Fe) were linked with the mortality of the exposed bivalves

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Identification of reproduction-specific genes associated with maturation and estrogen exposure in a marine bivalve Mytilus edulis.

    Directory of Open Access Journals (Sweden)

    Corina M Ciocan

    Full Text Available BACKGROUND: While it is established that vertebrate-like steroids, particularly estrogens (estradiol, estrone and androgens (testosterone, are present in various tissues of molluscs, it is still unclear what role these play in reproductive endocrinology in such organisms. This is despite the significant commercial shellfishery interest in several bivalve species and their decline. METHODOLOGY/PRINCIPAL FINDINGS: Using suppression subtraction hybridisation of mussel gonad samples at two stages (early and mature of gametogenesis and (in parallel following controlled laboratory estrogen exposure, we isolate several differentially regulated genes including testis-specific kinases, vitelline lysin and envelope sequences. CONCLUSIONS: The differentially expressed mRNAs isolated provide evidence that mussels may be impacted by exogenous estrogen exposure.

  16. Metals and pesticides in commercial bivalve mollusc production areas in the North and South Bays, Santa Catarina (Brazil).

    Science.gov (United States)

    de Souza, R V; Garbossa, L H P; Campos, C J A; Vianna, L F de N; Vanz, A; Rupp, G S

    2016-04-15

    Concentrations of heavy metals were quantified in mussels Perna perna and Pacific oysters Crassostrea gigas in 28 cultivation sites in the North and South Bays, SC (Brazil). Concentrations of pesticides were also quantified in these bivalve, water and sediment samples collected in 14 cultivation sites on four occasions in the period October 2012-October 2013. Pesticides were not detected in any of the mussel, oyster, water or sediment samples. The South Bay was found to be generally more contaminated with As while the North Bay showed higher concentrations of Ni. Concentrations of Pb and Cd were below the limit of detection of the method (0.5mg/kg) in all samples. Mussels accumulated more As and Ni than oysters, while the opposite was observed for Cu. Metal concentrations were below the maximum levels for foodstuffs specified in the Brazilian legislation. PMID:26897362

  17. 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.

  18. Interactive effects of pH and metals on mitochondrial functions of intertidal bivalves Crassostrea virginica and Mercenaria mercenaria

    Energy Technology Data Exchange (ETDEWEB)

    Ivanina, Anna V.; Sokolova, Inna M., E-mail: isokolov@uncc.edu

    2013-11-15

    Highlights: •Interactive effects of trace metals Cd and Cu and pH were studied in mitochondria of clams and oysters. •Mitochondrial respiration and membrane potential of bivalves were robust to pH variation (6.6–7.8). •Elevated levels of Cd and Cu inhibited mitochondrial respiration in the pH-dependent manner but did not affect the membrane potential. •Negative effects of Cd and Cd on mitochondrial respiration were alleviated at low pH (7.0 and below). •Moderate acidosis may protect molluscan mitochondria from metal toxicity. -- Abstract: Intertidal bivalves experience broad fluctuations of environmental temperature, pH and oxygen content which could change their intracellular pH. They are also exposed to trace metals such as cadmium (Cd) and copper (Cu) that accumulate in their tissues and may negatively affect mitochondrial functions and bioenergetics. We determined the interactive effects of pH and trace metals (25 μM Cd or Cu) on mitochondrial functions (including respiration and membrane potentials in both ADP-stimulated (state 3) and resting (state 4) states) of two common marine bivalves, the hard clams (Mercenaria mercenaria) and eastern oysters (Crassostrea virginica). In the absence of the trace metals, mitochondrial functions of C. virginica and M. mercenaria were insensitive to pH in a broad physiologically relevant range (6.6–7.8). Mitochondrial respiration was generally suppressed by 25 μM Cd or Cu (with the stronger effects observed for ADP-stimulated compared to the resting respiration) while the mitochondrial membrane potential was unaffected. pH modulated the effects of Cu and Cd on mitochondrial respiration of the bivalves. In oysters, Cu suppressed ADP-stimulated mitochondrial respiration at high and low pH values (6.6 and 7.8, respectively), but had no effect in the intermediate pH range (7.0–7.4). In clams, the negative effect of Cu on ADP-stimulated respiration was only observed at extremely high pH (7.8). A decrease in p

  19. Molecular phylogeny of the bivalve superfamily Galeommatoidea (Heterodonta, Veneroida reveals dynamic evolution of symbiotic lifestyle and interphylum host switching

    Directory of Open Access Journals (Sweden)

    Goto Ryutaro

    2012-09-01

    Full Text Available Abstract Background Galeommatoidea is a superfamily of bivalves that exhibits remarkably diverse lifestyles. Many members of this group live attached to the body surface or inside the burrows of other marine invertebrates, including crustaceans, holothurians, echinoids, cnidarians, sipunculans and echiurans. These symbiotic species exhibit high host specificity, commensal interactions with hosts, and extreme morphological and behavioral adaptations to symbiotic life. Host specialization to various animal groups has likely played an important role in the evolution and diversification of this bivalve group. However, the evolutionary pathway that led to their ecological diversity is not well understood, in part because of their reduced and/or highly modified morphologies that have confounded traditional taxonomy. This study elucidates the taxonomy of the Galeommatoidea and their evolutionary history of symbiotic lifestyle based on a molecular phylogenic analysis of 33 galeommatoidean and five putative galeommatoidean species belonging to 27 genera and three families using two nuclear ribosomal genes (18S and 28S ribosomal DNA and a nuclear (histone H3 and mitochondrial (cytochrome oxidase subunit I protein-coding genes. Results Molecular phylogeny recovered six well-supported major clades within Galeommatoidea. Symbiotic species were found in all major clades, whereas free-living species were grouped into two major clades. Species symbiotic with crustaceans, holothurians, sipunculans, and echiurans were each found in multiple major clades, suggesting that host specialization to these animal groups occurred repeatedly in Galeommatoidea. Conclusions Our results suggest that the evolutionary history of host association in Galeommatoidea has been remarkably dynamic, involving frequent host switches between different animal phyla. Such an unusual pattern of dynamic host switching is considered to have resulted from their commensalistic lifestyle, in

  20. 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.

  1. 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).

  2. The mismatch between bioaccumulation in field and laboratory environments: Interpreting the differences for metals in benthic bivalves

    International Nuclear Information System (INIS)

    Laboratory-based bioaccumulation and toxicity bioassays are frequently used to predict the ecological risk of contaminated sediments in the field. This study investigates the bioassay conditions most relevant to achieving environmentally relevant field exposures. An identical series of metal-contaminated marine sediments were deployed in the field and laboratory over 31 days. Changes in metal concentrations and partitioning in both sediments and waters were used to interpret differences in metal exposure and bioaccumulation to the benthic bivalve Tellina deltoidalis. Loss of resuspended sediments and deposition of suspended particulate matter from the overlying water resulted in the concentrations of Cu, Pb and Zn (major contaminants) becoming lower in the 1-cm surface layer of field-deployed sediments. Lower exchange rates of overlying waters in the laboratory resulted in higher dissolved metal exposures. The prediction of metal bioaccumulation by the bivalves in field and laboratory was improved by considering the metal partitioning within the surface sediments. - Highlights: • Particulate metals are the dominant metal exposure route in laboratory and field tests (87). • There is an over-representation of the dissolved metal exposure in the laboratory (81). • Laboratory bioassays result in higher bioaccumulation of major metals, Cu, Pb, Zn (82). • Differences in exposure must be considered for a proper sediment quality evaluation (83). • Traditional measurements are not sufficient to explain bioaccumulation results (79). - To improve the value of field- and laboratory-based sediment bioassays in ecological risk assessments, it is necessary to create exposure conditions that resemble those in the field

  3. Gene expression and physiological changes of different populations of the long-lived bivalve Arctica islandica under low oxygen conditions.

    Directory of Open Access Journals (Sweden)

    Eva E R Philipp

    Full Text Available The bivalve Arctica islandica is extremely long lived (>400 years and can tolerate long periods of hypoxia and anoxia. European populations differ in maximum life spans (MLSP from 40 years in the Baltic to >400 years around Iceland. Characteristic behavior of A. islandica involves phases of metabolic rate depression (MRD during which the animals burry into the sediment for several days. During these phases the shell water oxygen concentrations reaches hypoxic to anoxic levels, which possibly support the long life span of some populations. We investigated gene regulation in A. islandica from a long-lived (MLSP 150 years German Bight population and the short-lived Baltic Sea population, experimentally exposed to different oxygen levels. A new A. islandica transcriptome enabled the identification of genes important during hypoxia/anoxia events and, more generally, gene mining for putative stress response and (anti- aging genes. Expression changes of a antioxidant defense: Catalase, Glutathione peroxidase, manganese and copper-zinc Superoxide dismutase; b oxygen sensing and general stress response: Hypoxia inducible factor alpha, Prolyl hydroxylase and Heat-shock protein 70; and c anaerobic capacity: Malate dehydrogenase and Octopine dehydrogenase, related transcripts were investigated. Exposed to low oxygen, German Bight individuals suppressed transcription of all investigated genes, whereas Baltic Sea bivalves enhanced gene transcription under anoxic incubation (0 kPa and, further, decreased these transcription levels again during 6 h of re-oxygenation. Hypoxic and anoxic exposure and subsequent re-oxygenation in Baltic Sea animals did not lead to increased protein oxidation or induction of apoptosis, emphasizing considerable hypoxia/re-oxygenation tolerance in this species. The data suggest that the energy saving effect of MRD may not be an attribute of Baltic Sea A. islandica chronically exposed to high environmental variability (oxygenation

  4. 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.

  5. Element ratios between digestive gland and gill tissues of the Antarctic bivalve Laternula elliptica as a proxy for element uptake from different environmental sources

    Science.gov (United States)

    Poigner, H.; Monien, D.; Monien, P.; Kriews, M.; Brumsack, H.-J.; Wilhelms-Dick, D.; Abele, D.

    2012-04-01

    Trace metals in bivalve carbonate shells are frequently used as environmental or paleoclimate proxies. Carbonate mineralogy and animals' physiology affect the incorporation of elements from different environmental sources into bivalve shells. Generally, metals from particulate matter are assimilated via the digestive tract; whereas dissolved metals are absorbed via gills. Therefore, measurements of element concentrations deposited in the shell matrix do not necessarily allow inference with respect to the assimilation pathways. In this study, we used element ratios between digestive gland (DG) and gills (cDG/cGill) of the Circum-Antarctic clam Laternula elliptica to identify predominating assimilation pathways and potential sources of bio-available metals. This normalization between tissues of each individual eliminates the effects of individual age and physiological condition (e.g. accumulation over lifetime, metabolic activity) on metal assimilation. These effects also minimize the reproducibility, when absolute element concentrations are compared between individuals from different locations. Therefore, an additional normalization is required. We favored "ellipsoid shell volume" over shell length or soft tissue weight as more conservative approximation for intra- and intersite comparisons. Metal concentrations in DG, gills, and hemolymph of the bivalve L. elliptica, collected at Potter Cove (King George Island, Antarctic Peninsula), were analyzed by means of inductively coupled plasma - optical emission spectroscopy and mass spectrometry after total acid digestion. The element ratios (cDG/cGill) indicate a predominant assimilation of Al, Ca, Fe, K, Mn, and Mg from the dissolved phase. These high Al and Fe concentrations in gill tissues and hemolymph are in contrast to the low solubility of Al and Fe in seawater. But high dissolved Fe concentrations in pore waters (up to 1400 μg L-1 due to suboxic sediment conditions) and glacial melt waters enriched in dissolved

  6. 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...

  7. 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.

  8. Évaluation de la toxicité de pesticides sur quatre niveaux trophiques marins : microalgues, échinoderme, bivalves et poisson

    OpenAIRE

    Amara, Anis

    2012-01-01

    This work aims to study the effects of a few pesticides and one adjuvant on marine organisms, representatives of four trophic levels : micro-algae, echinoderm, bivalves and fish. Analysis of the pollu-sensitivity was based on the utilisation of existing bio-assays or adapted to this study.Phytotoxic assessments were conducted on three phytoplanktonic species (Chaetoceros calcitrans, Isochrysis aff. Galbana et Tetraselmis suecica) using the fungicide epoxiconazole and the adjuvant nonylphenol....

  9. Interactive effects of elevated temperature and CO(2) levels on metabolism and oxidative stress in two common marine bivalves (Crassostrea virginica and Mercenaria mercenaria).

    Science.gov (United States)

    Matoo, Omera B; Ivanina, Anna V; Ullstad, Claus; Beniash, Elia; Sokolova, Inna M

    2013-04-01

    Marine bivalves such as the hard shell clams Mercenaria mercenaria and eastern oysters Crassostrea virginica are affected by multiple stressors, including fluctuations in temperature and CO2 levels in estuaries, and these stresses are expected to be exacerbated by ongoing global climate change. Hypercapnia (elevated CO2 levels) and temperature stress can affect survival, growth and development of marine bivalves, but the cellular mechanisms of these effects are not yet fully understood. In this study, we investigated whether oxidative stress is implicated in cellular responses to elevated temperature and CO2 levels in marine bivalves. We measured the whole-organism standard metabolic rate (SMR), total antioxidant capacity (TAOC), and levels of oxidative stress biomarkers in the muscle tissues of clams and oysters exposed to different temperatures (22 and 27°C) and CO2 levels (the present day conditions of ~400ppm CO2 and 800ppm CO2 predicted by a consensus business-as-usual IPCC emission scenario for the year 2100). SMR was significantly higher and the antioxidant capacity was lower in oysters than in clams. Aerobic metabolism was largely temperature-independent in these two species in the studied temperature range (22-27°C). However, the combined exposure to elevated temperature and hypercapnia led to elevated SMR in clams indicating elevated costs of basal maintenance. No persistent oxidative stress signal (measured by the levels of protein carbonyls, and protein conjugates with malondialdehyde and 4-hydroxynonenal) was observed during the long-term exposure to moderate warming (+5°C) and hypercapnia (~800ppm CO2). This indicates that long-term exposure to moderately elevated CO2 and temperature minimally affects the cellular redox status in these bivalve species and that the earlier observed negative physiological effects of elevated CO2 and temperature must be explained by other cellular mechanisms. PMID:23319162

  10. 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.

  11. 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.

  12. 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

  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. PMID:27010163

  14. 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

  15. 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.

  16. 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.

  17. A complete Holocene record of trematode-bivalve infection and implications for the response of parasitism to climate change

    Science.gov (United States)

    Huntley, John Warren; Fürsich, Franz T.; Alberti, Matthias; Hethke, Manja; Liu, Chunlian

    2014-12-01

    Increasing global temperature and sea-level rise have led to concern about expansions in the distribution and prevalence of complex-lifecycle parasites (CLPs). Indeed, numerous environmental variables can influence the infectivity and reproductive output of many pathogens. Digenean trematodes are CLPs with intermediate invertebrate and definitive vertebrate hosts. Global warming and sea level rise may affect these hosts to varying degrees, and the effect of increasing temperature on parasite prevalence has proven to be nonlinear and difficult to predict. Projecting the response of parasites to anthropogenic climate change is vital for human health, and a longer term perspective (104 y) offered by the subfossil record is necessary to complement the experimental and historical approaches of shorter temporal duration (10-1 to 103 y). We demonstrate, using a high-resolution 9,600-y record of trematode parasite traces in bivalve hosts from the Holocene Pearl River Delta, that prevalence was significantly higher during the earliest stages of sea level rise, significantly lower during the maximum transgression, and statistically indistinguishable in the other stages of sea-level rise and delta progradation. This stratigraphic paleobiological pattern represents the only long-term high-resolution record of pathogen response to global change, is consistent with fossil and recent data from other marine basins, and is instructive regarding the future of disease. We predict an increase in trematode prevalence concurrent with anthropogenic warming and marine transgression, with negative implications for estuarine macrobenthos, marine fisheries, and human health.

  18. 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.

  19. 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.

  20. 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. PMID:25081847

  1. Shell Extracts from the Marine Bivalve Pecten maximus Regulate the Synthesis of Extracellular Matrix in Primary Cultured Human Skin Fibroblasts

    Science.gov (United States)

    Latire, Thomas; Legendre, Florence; Bigot, Nicolas; Carduner, Ludovic; Kellouche, Sabrina; Bouyoucef, Mouloud; Carreiras, Franck; Marin, Frédéric; Lebel, Jean-Marc; Galéra, Philippe; Serpentini, Antoine

    2014-01-01

    Mollusc shells are composed of more than 95% calcium carbonate and less than 5% of an organic matrix consisting mostly of proteins, glycoproteins and polysaccharides. Previous studies have elucidated the biological activities of the shell matrices from bivalve molluscs on skin, especially on the expression of the extracellular matrix components of fibroblasts. In this work, we have investigated the potential biological activities of shell matrix components extracted from the shell of the scallop Pecten maximus on human fibroblasts in primary culture. Firstly, we demonstrated that shell matrix components had different effects on general cellular activities. Secondly, we have shown that the shell matrix components stimulate the synthesis of type I and III collagens, as well as that of sulphated GAGs. The increased expression of type I collagen is likely mediated by the recruitment of transactivating factors (Sp1, Sp3 and human c-Krox) in the −112/−61 bp COL1A1 promoter region. Finally, contrarily to what was obtained in previous works, we demonstrated that the scallop shell extracts have only a small effect on cell migration during in vitro wound tests and have no effect on cell proliferation. Thus, our research emphasizes the potential use of shell matrix of Pecten maximus for dermo-cosmetic applications. PMID:24949635

  2. Investigation of Growth Patterns due to Environmental Factors on the Surface of Bivalve shells with LIBS and Raman Spectroscopy

    Science.gov (United States)

    Palmer, Andria; Mays, Joseph; Amos, James; Dynka, Tom; Ujj, Laszlo

    Environmental disturbances (such as temperature or chemical disturbances) can cause bivalve mollusk shells to grow faster or slower and cause changes in color and surface ring pattern. We have selected a few shells from our local habitat in Pensacola Beach, FL to analyze without sample treatment to determine what factors may have come into play during growth and use this as a way to analyze our marine environment. Laser Induced Breakdown Spectroscopy (LIBS) uses high energy laser pulses (355 and 532nm) to ablate the sample and create a micro-plasma from which emission spectra can be recorded. Based upon the analysis of intensities, wavelengths, and band patterns of spectral emission bands, the spatial qualitative elemental composition of the shell samples can be determined. Raman spectra were also recorded and correlated to molecules in the sample. By analyzing these measurements using LIBS-Raman spectroscopic techniques, we will be able to see how the local environment is effecting growth, with the largest chemical disturbance in the area being the BP Oil Spill in the Gulf in 2010. Therefore if samples are selected from this period of time it may be possible to identify the effects on shell growth. UWF NIH MARC U-STAR 1T34GM110517-01, UWF Office of Undergraduate Research.

  3. 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.

  4. 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.

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

    International Nuclear Information System (INIS)

    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

  6. 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.

  7. Dynamics of the abundance of some bivalve species in Russian waters of the Sea of Japan and its prognosis

    Science.gov (United States)

    Gabaev, D. D.

    2009-04-01

    The abundance dynamics of several species of bivalve mollusks spats were studied on scallop collectors situated in Minonosok bay of Pos’eta Gulf for 27 years and for 4 years in Kit bay of the Sea of Japan (Russia). A significant positive relation was found between the species having similar thermopathy: the Japanese scallop Mizuhopecten yessoensis and Swift’s scallop Swiftopecten swifti, as well as between the wrinkled rock borer Hiatella arctica and Swift’s scallop Swiftopecten swifti. A significant reverse relation was found between the bay mussel Mytilus trossulus and the Northern Pacific seastar Asterias amurensis. Some of the studied mollusks of Minonosok bay and the remote Kit bay display a significant reversed interrelation in their abundance dynamics caused by the precipitation regime. The one-way dispersion analysis a revealed significant influence of the water temperature in June and the precipitation abundance in the summer on Swift’s scallop’s dynamic abundance. The two-way dispersion analysis showed a significant influence of the ice period duration and the solar activity expressed in Wolf’s numbers on the Japanese scallop abundance dynamics. The uneven years in the period from 1977 to 1984 were usually productive for M. yessoensis and S. swifti spat. After 1985, the even years became more productive (there was asynchronicity in the abundance dynamics compared with 1977-1984). Such asynchronicity appeared with the advent of the new 22-year solar cycle, which caused a change in the magnet polarity in 1986.

  8. 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

  9. 皮肤红唇复合三角瓣并口轮匝肌功能性修复在先天性唇裂红唇整复中的应用%The application of composite skin-vermilion triangle fap and functional reposition of orbicularis muscle in congenital cleft lip

    Institute of Scientific and Technical Information of China (English)

    韦强; 徐思达; 陈石海; 刘庆丰; 廖明德

    2013-01-01

    目的 探讨更为理想的先天性唇裂红唇修复方法.方法 2010年3月至2013年1月,应用皮肤红唇复合三角瓣并口轮匝肌功能性修复的方法,对68例先天性唇裂患者行红唇整复及唇珠再造.结果 68例患者红唇部切口一期愈合,术后随访46例,时间为3个月至1年,其中8例有裂隙两侧红唇厚薄不均、唇珠偏歪的表现,其余病例唇弓线、唇吻线连续性良好,形态对称,唇珠外翘、饱满,位置适中.结论 口轮匝肌的精确复位是红唇整复及唇珠再造的关键,本方法设计简单、合理,可以很好地修复红唇.%Objective To investigate the ideal method for correction of vermilion deformity in congenital cleft lip.Methods From Mar.2010 to Jan.2013,68 cases with congenital cleft lip underwent vermilion deformities correction with composite skin-vermilion triangle fap and functional reposition of orbicularis oris muscle.Results Primary healing was achieved in all the patients.46 cases were followed up for 3 months to one year.Asymmetric thickness of vermilion and tubercle malposition happened in 8 cases.All the other patients had a satisfactory result with symmetric and fluent cupid' s bow and everting tubercle.Conclusion Well reposition of orbicularic oris muscle is key for correction of vermilion deformity and tubercle reconstruction.This technique is very simple and practical.

  10. Chromatin specialization in bivalve molluscs: a leap forward for the evaluation of Okadaic Acid genotoxicity in the marine environment.

    Science.gov (United States)

    González-Romero, Rodrigo; Rivera-Casas, Ciro; Fernández-Tajes, Juan; Ausió, Juan; Méndez, Josefina; Eirín-López, José M

    2012-03-01

    Marine biotoxins synthesized by Harmful Algal Blooms (HABs) represent one of the most important sources of contamination in marine environments as well as a serious threat to fisheries and aquaculture-based industries in coastal areas. Among these biotoxins Okadaic Acid (OA) is of critical interest as it represents the most predominant Diarrhetic Shellfish Poisoning biotoxin in the European coasts. Furthermore, OA is a potent tumor promoter with aneugenic and clastogenic effects on the hereditary material, most notably DNA breaks and alterations in DNA repair mechanisms. Therefore, a great effort has been devoted to the biomonitoring of OA in the marine environment during the last two decades, mainly based on physicochemical and physiological parameters using mussels as sentinel organisms. However, the molecular genotoxic effects of this biotoxin make chromatin structure a good candidate for an alternative strategy for toxicity assessment with faster and more sensitive evaluation. To date, the development of chromatin-based studies to this purpose has been hampered by the complete lack of information on chromatin of invertebrate marine organisms, especially in bivalve molluscs. Our preliminary results have revealed the presence of histone variants involved in DNA repair and chromatin specialization in mussels and clams. In this work we use this information to put forward a proposal focused on the development of chromatin-based tests for OA genotoxicity in the marine environment. The implementation of such tests in natural populations has the potential to provide an important leap in the biomonitoring of this biotoxin. The outcome of such monitoring may have critical implications for the evaluation of DNA damage in these marine organisms. They will provide as well important tools for the optimization of their harvesting and for the elaboration of additional tests designed to evaluate the safety of their consumption and potential implications for consumer's health.

  11. Liquid chromatography quadrupole linear ion trap mass spectrometry for multiclass screening and identification of lipophilic marine biotoxins in bivalve mollusks.

    Science.gov (United States)

    Wu, Haiyan; Guo, Mengmeng; Tan, Zhijun; Cheng, Haiyan; Li, Zhaoxin; Zhai, Yuxiu

    2014-09-01

    A liquid chromatography quadrupole linear ion trap mass spectrometry method with fast polarity switching and a scheduled multiple reaction monitoring algorithm mode was developed for multiclass screening and identification of lipophilic marine biotoxins in bivalve molluscs. A major advantage of the method is that it can detect members of all six groups of lipophilic marine biotoxins [okadaic acid (OA), yessotoxins (YTX), azaspiracids (AZA), pectenotoxins (PTX), cyclic imines (CI), and brevetoxins (PbTx)], thereby allowing quantification and high confidence identification from a single liquid chromatography tandem mass spectrometry (LC-MS/MS) injection. An enhanced product ion (EPI) library was constructed after triggered collection of data via information-dependent acquisition (IDA) of EPI spectra from standard samples. A separation method for identifying 17 target toxins in a single analysis within 12min was developed and tested. Different solid phase extraction sorbents, the matrix effect (for oyster, scallop, and mussel samples), and stability of the standards also were evaluated. Matrix-matched calibration was used for quantification of the toxins. The limits of detection were 0.12-13.6μg/kg, and the limits of quantification were 0.39-45.4μg/kg. The method was used to analyze 120 shellfish samples collected from farming areas along the coast of China, and 7% of the samples were found to be contaminated with toxins. The library search identified PbTx-3, YTX, OA, PTX2, AZA1, AZA2, and desmethylspirolide C (SPX1). Overall, the method exhibited excellent sensitivity and reproducibility, and it will have broad applications in the monitoring of lipophilic marine biotoxins.

  12. SNP detection from de novo transcriptome sequencing in the bivalve Macoma balthica: marker development for evolutionary studies.

    Directory of Open Access Journals (Sweden)

    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.

  13. 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.

  14. Short-Term and Long-Term Biological Effects of Chronic Chemical Contamination on Natural Populations of a Marine Bivalve.

    Science.gov (United States)

    Breitwieser, Marine; Viricel, Amélia; Graber, Marianne; Murillo, Laurence; Becquet, Vanessa; Churlaud, Carine; Fruitier-Arnaudin, Ingrid; Huet, Valérie; Lacroix, Camille; Pante, Eric; Le Floch, Stéphane; Thomas-Guyon, Hélène

    2016-01-01

    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. PMID:26938082

  15. Short-Term and Long-Term Biological Effects of Chronic Chemical Contamination on Natural Populations of a Marine Bivalve.

    Directory of Open Access Journals (Sweden)

    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.

  16. Genetic inviability is a major driver of type III survivorship in experimental families of a highly fecund marine bivalve.

    Science.gov (United States)

    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.

  17. 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. PMID:26115607

  18. 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.

  19. Liquid chromatography quadrupole linear ion trap mass spectrometry for multiclass screening and identification of lipophilic marine biotoxins in bivalve mollusks.

    Science.gov (United States)

    Wu, Haiyan; Guo, Mengmeng; Tan, Zhijun; Cheng, Haiyan; Li, Zhaoxin; Zhai, Yuxiu

    2014-09-01

    A liquid chromatography quadrupole linear ion trap mass spectrometry method with fast polarity switching and a scheduled multiple reaction monitoring algorithm mode was developed for multiclass screening and identification of lipophilic marine biotoxins in bivalve molluscs. A major advantage of the method is that it can detect members of all six groups of lipophilic marine biotoxins [okadaic acid (OA), yessotoxins (YTX), azaspiracids (AZA), pectenotoxins (PTX), cyclic imines (CI), and brevetoxins (PbTx)], thereby allowing quantification and high confidence identification from a single liquid chromatography tandem mass spectrometry (LC-MS/MS) injection. An enhanced product ion (EPI) library was constructed after triggered collection of data via information-dependent acquisition (IDA) of EPI spectra from standard samples. A separation method for identifying 17 target toxins in a single analysis within 12min was developed and tested. Different solid phase extraction sorbents, the matrix effect (for oyster, scallop, and mussel samples), and stability of the standards also were evaluated. Matrix-matched calibration was used for quantification of the toxins. The limits of detection were 0.12-13.6μg/kg, and the limits of quantification were 0.39-45.4μg/kg. The method was used to analyze 120 shellfish samples collected from farming areas along the coast of China, and 7% of the samples were found to be contaminated with toxins. The library search identified PbTx-3, YTX, OA, PTX2, AZA1, AZA2, and desmethylspirolide C (SPX1). Overall, the method exhibited excellent sensitivity and reproducibility, and it will have broad applications in the monitoring of lipophilic marine biotoxins. PMID:25086754

  20. Role of non-enzymatic antioxidants on the bivalves' adaptation to environmental mercury: Organ-specificities and age effect in Scrobicularia plana inhabiting a contaminated lagoon

    International Nuclear Information System (INIS)

    This study aimed to investigate the role of non-enzymatic antioxidants on adaptive skills over time in the bivalve Scrobicularia plana environmentally exposed to mercury. Inter-age (2+, 3+, 4+, 5+ year old) and organ-specific (gills, digestive gland) approaches were applied in bivalves collected from moderately and highly contaminated sites at Ria de Aveiro (Portugal). S. plana's adaptive skills were dependent on the contamination extent; under moderate contamination scenario, the intervention of the different antioxidants took place harmoniously, evidencing an adjustment capacity increasing with the age. Under higher contamination degree, S. plana failed to cope with mercury threat, showing an age-dependent deterioration of the defense abilities. In organ-specific approach, the differences were particularly evident for thiol-compounds, since only gills displayed the potential to respond to moderate levels by increasing non-protein thiols and total glutathione. Under high contamination degree, both organs were unable to increase thiol-compounds, which were compensated by the ascorbic acid elevation. - Highlights: ► Results demonstrated non-enzymatic antioxidants' importance on protecting bivalves. ► S. plana's adaptive skills over time depend on the contamination extent. ► Antioxidants intervention evidenced an adjustment capacity increasing with the age. ► Gills responded to mercury moderate levels by increasing thiols and glutathione. ► Ascorbic acid displayed a compensatory role where organs failed to increase thiols. - Results demonstrated the importance of non-enzymatic antioxidants on protecting S. plana from mercury pro-oxidant action, under environmentally realistic conditions.

  1. Long-term trends in accumulated metals (Cd, Cu and Zn) and metallothionein in bivalves from lakes within a smelter-impacted region.

    Science.gov (United States)

    Perceval, Olivier; Couillard, Yves; Pinel-Alloul, Bernadette; Bonneris, Emmanuelle; Campbell, Peter G C

    2006-10-01

    Temporal monitoring studies are needed to detect long-term trends in ecosystem health. In the present study, we tested metallothionein (MT) as a potential biomarker for long-term variations in trace metal levels in lakes subject to atmospheric metal inputs from a nearby copper smelter. Over a 13-year period, we estimated on several occasions ambient free Cd2+, Cu2+ and Zn2+ concentrations at the sediment-water interface in six lakes with contrasting metal levels, and measured metal and metallothionein concentrations in gills of bivalves (Pyganodon grandis) living in these lakes. All but one of the study lakes had comparable drainage ratios, so inter-lake differences in hydrological export of metals from contaminated watersheds to receiving waters were likely minimal. Declines in the metal emissions from the smelter (especially for Cd and Zn) during the 1980s led to appreciable decreases in both calculated free Cd2+ ion concentrations in the study lakes (-59+/-21% between 1989 and 1998) and accumulated Cd levels in their clam populations (-46+/-12% between 1989 and 2002). Taking all lakes into account, MT concentrations in bivalves have comparatively dropped by 44% (+/-10%) since 1989. In contrast to what we found for Cd, there were no significant reductions in the calculated free Cu2+ and Zn2+ concentrations in the various lakes during our study period (-2 and -10%, respectively, with 95% confidence intervals spanning zero). Overall, observed decreases in MT in bivalves over time were best correlated with similar decreases in both ambient and accumulated Cd levels (r = 0.77, P = 0.0003 and r = 0.79, P < 0.0001, respectively, both P-values corrected for temporal autocorrelation), suggesting that long-term trends in gill MT concentrations in P. grandis may be useful as predictors of temporal changes in environmental Cd contamination in lakes. PMID:16814847

  2. Solid-phase extraction-based ultra-sensitive detection of four lipophilic marine biotoxins in bivalves by high-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Fang, Lanyun; Yao, Xunping; Wang, Li; Li, Jige

    2015-02-01

    A solid-phase extraction (SPE) method for ultra-sensitive determination of four lipophilic marine biotoxins in bivalve samples by coupling high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) was developed. Azaspiracid-2 (AZA2), pectenotoxins-2, spirolide (SPX) and gymnodimine were simultaneously determined by HPLC-MS-MS in a positive multiple reaction monitoring mode. Separation was achieved on a reversed-phase C18 column with an acetonitrile-water gradient containing formic acid. During the analysis, solvent effects on the analytes were eliminated by using 1 : 1 water-methanol as dissolving solvent instead of pure methanol. Matrix effects in post-SPE extract and crude extract were seriously evaluated. Increased matrix effects in post-SPE extract countervailed the concentration purpose to some extent. The limits of detection of the SPE-HPLC-MS-MS method were determined to be in the range of 0.013-0.085 µg kg(-1), and the linear range of the method was in the range of 0.128-55.2 ng mL(-1) for the detected toxins. The proposed method was validated in terms of linearity (matrix-matched standard curves), precision, recovery, repeatability and limits of quantification. The recoveries of fortified samples at three different concentration levels were satisfactory, and the intra- and interday precisions were <7 and 10%, respectively.Several bivalve samples were analyzed to demonstrate the applicability of the proposed method. Different target toxins were detected in different kind of bivalves. Among them, AZA2 and SPX1 were first detected in Chinese shellfish. The levels of detected toxins were below the current European Union regulatory limits.

  3. Solid-phase extraction-based ultra-sensitive detection of four lipophilic marine biotoxins in bivalves by high-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Fang, Lanyun; Yao, Xunping; Wang, Li; Li, Jige

    2015-02-01

    A solid-phase extraction (SPE) method for ultra-sensitive determination of four lipophilic marine biotoxins in bivalve samples by coupling high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) was developed. Azaspiracid-2 (AZA2), pectenotoxins-2, spirolide (SPX) and gymnodimine were simultaneously determined by HPLC-MS-MS in a positive multiple reaction monitoring mode. Separation was achieved on a reversed-phase C18 column with an acetonitrile-water gradient containing formic acid. During the analysis, solvent effects on the analytes were eliminated by using 1 : 1 water-methanol as dissolving solvent instead of pure methanol. Matrix effects in post-SPE extract and crude extract were seriously evaluated. Increased matrix effects in post-SPE extract countervailed the concentration purpose to some extent. The limits of detection of the SPE-HPLC-MS-MS method were determined to be in the range of 0.013-0.085 µg kg(-1), and the linear range of the method was in the range of 0.128-55.2 ng mL(-1) for the detected toxins. The proposed method was validated in terms of linearity (matrix-matched standard curves), precision, recovery, repeatability and limits of quantification. The recoveries of fortified samples at three different concentration levels were satisfactory, and the intra- and interday precisions were <7 and 10%, respectively.Several bivalve samples were analyzed to demonstrate the applicability of the proposed method. Different target toxins were detected in different kind of bivalves. Among them, AZA2 and SPX1 were first detected in Chinese shellfish. The levels of detected toxins were below the current European Union regulatory limits. PMID:24935918

  4. 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.

  5. The use of algal substitutes and the requirement for live algae in the hatchery and nursery rearing of bivalve molluscs: an international survey

    OpenAIRE

    Coutteau, P.; Sorgeloos, P.

    1992-01-01

    The mass-production of micro-algae has been recognized by several authors as the main bottle-neck for the culture of bivalve seed. This has prompted a search for alternatives to on-site algal production, such as dried heterotrophically-grown algae, preserved algal pastes, micro-encapsulated diets, and yeasts. However the extent to which these products have been tried, and rejected or retained by hatchery operators is poorly documented. Also, the actual algal requirement and production cost of...

  6. 应用于贝类生理生态学研究的生物沉积法%Biodeposition Method used in Bivalval Physio-Ecological Studies

    Institute of Scientific and Technical Information of China (English)

    周毅; 杨红生

    2002-01-01

    Biodeposition method, a recently developed method used in studies on physio-ecological characteristics of bivalval mollusks,including clearance rate (CR), ingestion rate (IR), absorption efficiency (AE) and energy budget, is reviewed in this paper. The method estimates feeding and absorption rates through measurements of suspended particles and biodeposit production. The main assumption of this method is that ingested particulate inorganic matter can be used as an inert tracer of feeding and digestive processes. The method is based on feeding responses that are integrated over long time scales, reducing the variability on the measurements affecting growth parameters associated to instantaneous responses.

  7. 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.

    Directory of Open Access Journals (Sweden)

    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

  8. Evaluation of microwave and ultrasound extraction procedures for arsenic speciation in bivalve mollusks by liquid chromatography–inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    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−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

  9. Evaluation of microwave and ultrasound extraction procedures for arsenic speciation in bivalve mollusks by liquid chromatography-inductively coupled plasma-mass spectrometry

    Science.gov (United States)

    Santos, Clarissa M. M.; Nunes, Matheus A. G.; Barbosa, Isa S.; Santos, Gabriel L.; Peso-Aguiar, Marlene C.; Korn, Maria G. A.; Flores, Erico M. M.; Dressler, Valderi L.

    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- 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.

  10. Bivalve shell horizons in seafloor pockmarks of the last glacial-interglacial transition: a thousand years of methane emissions in the Arctic Ocean

    Science.gov (United States)

    Ambrose, William G.; Panieri, Giuliana; Schneider, Andrea; Plaza-Faverola, Andreia; Carroll, Michael L.; Åström, Emmelie K. L.; Locke, William L.; Carroll, JoLynn

    2015-12-01

    We studied discrete bivalve shell horizons in two gravity cores from seafloor pockmarks on the Vestnesa Ridge (˜1200 m water depth) and western Svalbard (79°00' N, 06°55' W) to provide insight into the temporal and spatial dynamics of seabed methane seeps. The shell beds, dominated by two genera of the family Vesicomyidae: Phreagena s.l. and Isorropodon sp., were 20-30 cm thick and centered at 250-400 cm deep in the cores. The carbon isotope composition of inorganic (δ13C from -13.02‰ to +2.36‰) and organic (δ13C from -29.28‰ to -21.33‰) shell material and a two-end member mixing model indicate that these taxa derived between 8% and 43% of their nutrition from chemosynthetic bacteria. In addition, negative δ13C values for planktonic foraminifera (-6.7‰ to -3.1‰), concretions identified as methane-derived authigenic carbonates, and pyrite-encrusted fossil worm tubes at the shell horizons indicate a sustained paleo-methane seep environment. Combining sedimentation rates with 14C ages for bivalve material from the shell horizons, we estimate the horizons persisted for about 1000 years between approximately 17,707 and 16,680 years B.P. (corrected). The seepage event over a 1000 year time interval was most likely associated with regional stress-related faulting and the subsequent release of overpressurized fluids.

  11. Bivalve Shell Horizons in Seafloor Pockmarks of the Last Glacial-interglacial Transition Suggest a Thousand Years of Methane Emissions in the Arctic Ocean

    Science.gov (United States)

    Ambrose, W. G., Jr.; Panieri, G.; Schneider, A.; Plaza-Faverola, A. A.; Carroll, M.; Åström, E. K. L.; Locke, W. L.; Carroll, J.

    2015-12-01

    We studied discrete bivalve shell horizons, in two gravity cores from seafloor pockmarks on the Vestnesa Ridge (ca. 1200 m water depth), western Svalbard (79° 00' N, 06° 55' W) to provide insight into the temporal and spatial dynamics of seabed methane seeps. The shell beds, are dominated by two genera of the family Vesicomyidae: Phreagena s.l. and Isorropodon sp. were 20-30cm thick centered at 250-400cm depth in the cores. The carbon isotope composition of inorganic (δ13C from -13.02‰ to +2.364‰) and organic (δ13C from -29.283‰ to -21.33‰) shell material indicates that these taxa derived their energy primarily from endosymbiotic chemosynthetic bacteria feeding on methane. In addition, negative δ13C values for planktonic foraminifera (-6.7‰ to -3.1‰), micritic concretions identified as methane-derived authigenic carbonates and pyrite encrusted fossil worm tubes at the shell horizons indicate a sustained paleo-methane seep environment. Combining sedimentation rates with 14C ages for bivalve material from the shell horizons, we estimate the horizons persisted for about 1000 years between approximately 17,707 to 16,680 yrs. BP (corrected). The major seepage event over a 1000 -year time interval was most likely triggered by tectonic stress and the subsequent release of over-pressurized fluids.

  12. Cadmium contamination of three bivalve species (oysters, cockles and clams) in Nord Médoc salt marshes (Gironde estuary, France): Geochemical survey and metal bioaccumulation kinetics

    Science.gov (United States)

    Baudrimont, M.; Schäfer, J.; Marie, V.; Maury-Brachet, R.; Bossy, C.; Durrieu, G.; Palvadeau, A.; Maneux, E.; Boudou, A.; Blanc, G.

    2003-05-01

    A historical Cd pollution of the Lot-Garonne River system (France) bas led to the contamination of sediment and water of the Gironde Estuary. In spite of the decrease of fluvial Cd inputs since the early 90ies, Cd concentrations in the Gironde oysters remain higher than European norms (5 μg.g^{-1} dry mass) and the “zone D” classification of the estuary prohibits bivalve production and harvesting for human consumption. A geochemical survey in salt marshes used for aquaculture (crustaceans) has been conducted in order to assess the heavy métal contamination level in these systems periodically alimented by the Gironde water, accompanied by caging experiments on three bivalve species of economical interest: oysters (Crassostrea gigas), cockles (Cerastoderma edule) and clams (Ruditapes philippinarum) to study heavy metal accumulation in these organisms. Distribution of heavy metals in this system is controlled by biogeochemical processes and is independent of routine water management. Contamination levels in the studied species indicate the high accumulation of Cd by oysters. On the other hand, Cd concentrations in benthic species, such as cockles and clams, are clearly lower than European safety limits for human consumption.

  13. 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.

  14. Deep-water bivalve mollusks collected during the TALUD XV cruise off the west coast of the southern Baja California Peninsula, Mexico

    Science.gov (United States)

    Valentich-Scott, Paul; Suárez-Mozo, Nancy Yolimar

    2016-01-01

    Abstract Background During the TALUD XV research cruise off the southern part of the Baja California Peninsula, Mexico, samples of macro-invertebrates obtained in the deep-sea (296–2136 m) revealed a rich fauna of bivalves (17 species belonging to 10 families). The number of species per station varied from one to five. The richest families were Nuculidae, Nuculanidae, Neilonellidae, Limidae, and Cuspidariidae. Solemyidae, Lucinidae, Poromyidae, Verticordiidae, and Pectinidae were each represented by a single species. Some species groups need a thorough revision and were tentatively identified (Nuculana cf. hamata, Limatula cf. saturna). New information Significant new distribution information is provided for two species, both recorded for the first time from off western Mexico: Ennucula panamina with an extension of its known distribution over 20° of latitude north and Jupiteria callimene with an extension of 16° 42' of latitude to the north. One species (Ennucula taeniolata) is reported in shallower depth and one in deeper water (Acesta sphoni). New records are provided for an additional nine species. Environmental and habitat conditions are given for the first time for many of the bivalve species. PMID:27346956

  15. 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.

  16. 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.

  17. 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.

  18. Effects of arctic temperatures on distribution and retention of the nuclear waste radionuclides 241Am, 57Co, and 137Cs in the bioindicator bivalve Macoma balthica

    Science.gov (United States)

    Hutchins, D.A.; Stupakoff, I.; Hook, S.; Luoma, S.N.; Fisher, N.S.

    1998-01-01

    The disposal of radioactive wastes in Arctic seas has made it important to understand the processes affecting the accumulation of radionuclides in food webs in coldwater ecosystems. We examined the effects of temperature on radionuclide assimilation and retention by the bioindicator bivalve Macoma balthica using three representative nuclear waste components, 241Am, 57Co, and 137Cs. Experiments were designed to determine the kinetics of processes that control uptake from food and water, as well as kinetic constants of loss. 137Cs was not accumulated in soft tissue from water during short exposures, and was rapidly lost from shell with no thermal dependence. No effects of temperature on 57Co assimilation or retention from food were observed. The only substantial effect of polar temperatures was that on the assimilation efficiency of 241Am from food, where 10% was assimilated at 2??C and 26% at 12??C. For all three radionuclides, body distributions were correlated with source, with most radioactivity obtained from water found in the shell and food in the soft tissues. These results suggest that in general Arctic conditions had relatively small effects on the biological processes which influence the bioaccumulation of radioactive wastes, and bivalve concentration factors may not be appreciably different between polar and temperate waters.

  19. 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

  20. Immunomodulation by the interactive effects of cadmium and hypercapnia in marine bivalves Crassostrea virginica and Mercenaria mercenaria.

    Science.gov (United States)

    Ivanina, Anna V; Hawkins, Chelsea; Sokolova, Inna M

    2014-04-01

    Estuarine organisms are exposed to multiple stressors including large fluctuations in partial pressure of carbon dioxide (P2CO) and concentrations of trace metals such as cadmium (Cd) that can affect their survival and fitness. Ocean acidification due to the increasing atmospheric (P2CO) leads to a decrease in pH and shifts in the carbonate chemistry of seawater which can change bioavailability and toxicity of metals. We studied the interactive effects of (P2CO) and Cd exposure on metal levels, metabolism and immune-related functions in hemocytes of two ecologically and economically important bivalve species, Mercenaria mercenaria (hard shell clam) and Crassostrea virginica (Eastern oyster). Clams and oysters were exposed to combinations of three (P2CO) levels (∼400, 800 and 2000 μatm (P2CO), corresponding to the present day conditions and the projections for the years 2100 and 2250, respectively) and two Cd concentrations (0 and 50 μg l(-1)) in seawater. Following four weeks of exposure to Cd, hemolymph of both species contained similar Cd levels (50-70 μg l(-1)), whereas hemocytes accumulated intracellular Cd burdens up to 15-42 mg l(-1), regardless of the exposure P2CO. Clam hemocytes had considerably lower Cd burdens than those of oysters (0.7-1 ng 10(-6) cells vs. 4-6 ng 10(-6) cells, respectively). Cd exposure suppressed hemocyte metabolism and increased the rates of mitochondrial proton leak in normocapnia indicating partial mitochondrial uncoupling. This Cd-induced mitochondrial uncoupling was alleviated in hypercapnia. Cd exposure suppressed immune-related functions in hemocytes of clams and oysters, and these effects were exacerbated at elevated (P2CO). Thus, elevated (P2CO) combined with Cd exposure resulted in decrease in phagocytic activity and adhesion capacity as well as lower expression of mRNA for lectin and heat shock protein (HSP70) in clam and oyster hemocytes. In oysters, combined exposure to elevated (P2CO) and Cd also led to reduced

  1. 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.

  2. 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

  3. 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. PMID:27002718

  4. 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

  5. Mg-isotopic fractionation in the manila clam (Ruditapes philippinarum): New insights into Mg incorporation pathway and calcification process of bivalves

    Science.gov (United States)

    Planchon, Frédéric; Poulain, Céline; Langlet, Denis; Paulet, Yves-Marie; André, Luc

    2013-11-01

    We estimate the magnesium stable isotopic composition (δ26Mg) of the major compartments involved in the biomineralisation process of euryhaline bivalve, the manila clam Ruditapes philippinarum. Our aim is to identify the fractionation processes associated with Mg uptake and its cycling/transport in the bivalve organism, in order to better assess the controlling factors of the Mg isotopic records in bivalve shells. δ26Mg were determined in seawater, in hemolymph, extrapallial fluid (EPF), soft tissues and aragonitic shell of adult clams collected along the Auray River estuary (Gulf of Morbihan, France) at two sites showing contrasted salinity regimes. The large overall δ26Mg variations (4.16‰) demonstrate that significant mass-dependent Mg isotopic fractionations occur during Mg transfer from seawater to the aragonitic shell. Soft tissues span a range of fractionation factors relative to seawater (Δ26Mgsoft tissue-seawater) of 0.42 ± 0.12‰ to 0.76 ± 0.12‰, and show evidence for biological isotopic fractionation of Mg. Hemolymph and EPF are on average isotopically close to seawater (Δ26Mghemolymph-seawater = -0.20 ± 0.27‰; 2 sd; n = 5 and Δ26MgEPF-seawater = -0.23 ± 0.25‰; 2 sd; n = 5) indicating (1) a predominant seawater origin for Mg in the intercellular medium and (2) a relatively passive transfer route through the bivalve organism into the calcifying fluid. The lightest isotopic composition is found in shell, with δ26Mg ranging from -1.89 ± 0.07‰ to -4.22 ± 0.06‰. This range is the largest in the dataset and is proposed to result from a combination of abiotic and biologically-driven fractionation processes. Abiotic control includes fractionation during precipitation of aragonite and accounts for Δ26Mgaragonite-seawater ≈ 1000 ln αaragonite-seawater = -1.13 ± 0.28‰ at 20 °C based on literature data. Deviations from inorganic precipitate (expressed as Δ26MgPhysiol) appear particularly variable in the clam shell, ranging from 0

  6. 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...

  7. 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

  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

    International Nuclear Information System (INIS)

    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. 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.

  10. Polycyclic aromatic hydrocarbon levels and measures of oxidative stress in the Mediterranean endemic bivalve Pinna nobilis exposed to the Don Pedro oil spill.

    Science.gov (United States)

    Sureda, Antoni; Tejada, Silvia; Box, Antonio; Deudero, Salud

    2013-06-15

    The fan mussel (Pinna nobilis Linné, 1758) is the largest endemic Mediterranean bivalve subject to strict protection as an endangered species. Antioxidant biomarkers in P. nobilis gills for biomonitoring marine pollution were researched after the Don Pedro oil spill. Two sampling locations on the east and southeast of the island of Ibiza (Western Mediterranean, Spain) were selected, one extensively affected by the oil spill and the other unaffected (control area). Mussels were sampled 1 month, 6 months and 1 year after the accident. Polycyclic aromatic hydrocarbon levels and antioxidant enzymes significantly increased as result of the oil spill in all sampling periods (p<0.05). Oxidative damage in lipids significantly increased in the mussels collected in the affected area (p<0.05), though such damage was back to normal after 1 year. In conclusion, the Don Pedro oil spill induced a situation of oxidative stress on P. nobilis that continued a year later. PMID:23623655

  11. 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.

  12. Interactive effects of CO₂ and trace metals on the proteasome activity and cellular stress response of marine bivalves Crassostrea virginica and Mercenaria mercenaria.

    Science.gov (United States)

    Götze, Sandra; Matoo, Omera B; Beniash, Elia; Saborowski, Reinhard; Sokolova, Inna M

    2014-04-01

    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 ( [Formula: see text] ∼ 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 [Formula: see text] 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 [Formula: see text] , but [Formula: see text] modulated the proteasome response to metals. Cd exposure stimulated the chymotrypsin-like activity of the oyster proteasome at all CO2 levels. In contrast, trypsin- and caspase-like activities of the oyster proteasome were slightly inhibited by Cd exposure in normocapnia but this inhibition was reversed at elevated [Formula: see text] . Cu exposure inhibited the chymotrypsin-like activity of the oyster proteasome regardless of the exposure [Formula: see text] . The effects of metal exposure on

  13. 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.

  14. 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. PMID:27494189

  15. 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 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 bioaccumulation and biotransformation they will thereafter exhibit. PMID:23822152

  16. 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.

  17. Late Pleistocene monsoon variability in northwest Thailand: an oxygen isotope sequence from the bivalve Margaritanopsis laosensis excavated in Mae Hong Son province

    Science.gov (United States)

    Marwick, Ben; Gagan, Michael K.

    2011-10-01

    Long, continuous records of Late Quaternary environmental change are rare in Southeast Asia, yet they are crucial for understanding the nature of early human dispersal and occupation in the Australasian region. We present a new record of palaeomonsoon activity extending back to 35,000 BP (years before the present), based on the analysis of oxygen isotope ratios (δ 18O) in the freshwater bivalve Margaritanopsis laosensis excavated from the Tham Lod and Ban Rai rockshelters in Mae Hong Son Province, northwest Thailand. Long-term changes in the M. laosensis δ 18O record reflect changes in the δ 18O of the river water in which these organisms grew, and correlate well with changes in speleothem δ 18O records of east Asian monsoon rainfall from Hulu Cave and Dongge Cave in China. The new northwest Thailand δ 18O sequence indicates wetter and relatively unstable climatic conditions from 35,000 to 20,000 BP, followed by drier conditions from 20,000 to 11,500 BP. A period of peak aridity occurred around 15,600 BP during Heinrich Event 1, suggesting that the intertropical convergence zone shifted southward when the North Atlantic region cooled. However, there is little evidence for the Younger Dryas event at ˜12,800-11,500 BP. After 9,800 BP, precipitation increased substantially and climatic variability declined. Our findings provide an improved baseline against which to gauge interactions between early humans and climate change in Southeast Asia. For example, there was no significant change in the prehistoric flake stone technology used at Tham Lod and Ban Rai despite the bivalve δ 18O evidence for substantial climate change in the region. Also, the climatic impact of the Younger Dryas event appears to have been less intense in northwest Thailand compared to the cooling and drying observed in China, and may explain why agriculture made a relatively late appearance in Thailand, possibly involving migrants from China.

  18. 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

    Energy Technology Data Exchange (ETDEWEB)

    Company, R. [CIMA, Faculty of Marine and Environmental Sciences, University of Algarve, Campus de Gambelas, 8005-139 Faro (Portugal)], E-mail: rcompany@ualg.pt; Serafim, A.; Lopes, B.; Cravo, A. [CIMA, Faculty of Marine and Environmental Sciences, University of Algarve, Campus de Gambelas, 8005-139 Faro (Portugal); Shepherd, T.J.; Pearson, G. [Department of Earth Sciences, Durham University, Science Labs., Durham DH1 3LE (United Kingdom); Bebianno, M.J. [CIMA, Faculty of Marine and Environmental Sciences, University of Algarve, Campus de Gambelas, 8005-139 Faro (Portugal)], E-mail: mbebian@ualg.pt

    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 {sup 206}Pb/{sup 204}Pb, {sup 207}Pb/{sup 204}Pb, {sup 208}Pb/{sup 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.

  19. Testing cosmic dose rate models for ESR: Dating corals and molluscs on San Salvador, Bahamas

    Energy Technology Data Exchange (ETDEWEB)

    Deely, A.E. [RFK Science Research Institute, Glenwood Landing, NY, 11547-0866 (United States); Blackwell, B.A.B., E-mail: bonnie.a.b.blackwell@williams.edu [RFK Science Research Institute, Glenwood Landing, NY, 11547-0866 (United States); Dept. of Chemistry, Williams College, Williamstown MA, 01267-2692 (United States); Mylroie, J.E. [Dept. of Geosciences, Mississippi State University, MS, 39762-5448 (United States); Carew, J.L. [Dept. of Geology and Environmental Geosciences, College of Charleston, Charleston, SC 29424 (United States); Blickstein, J.I.B. [RFK Science Research Institute, Glenwood Landing, NY, 11547-0866 (United States); Skinner, A.R. [RFK Science Research Institute, Glenwood Landing, NY, 11547-0866 (United States); Dept. of Chemistry, Williams College, Williamstown MA, 01267-2692 (United States)

    2011-09-15

    Sealevel curves are best developed on tectonically stable coastlines, like San Salvador, where eolianites preserve transgressive and regressive phases associated with Quaternary high seastands, while reef facies mark the highstands. At 11 locations around San Salvador, terrestrial molluscs (Cerion) from the eolianites, lagoonal bivalves (Codakia), and corals from the highstand deposits were dated by ESR. Volumetrically averaged sedimentary dose rates were calculated from sedimentary geochemistry and time-averaged cosmic dose rates from each sample's current and past geologic contexts. Rice Bay Formation corals dated at 3.9 {+-} 0.3 to 7.1 {+-} 0.4 ka (OIS 1). Minimum ages for the Cockburn Town Member's regressive phase ranged from 49 {+-} 6 to 75 {+-} 8 ka, correlating with OIS 3-4. Codakia dates showed that an OIS 5a sealevel approached modern levels at 91-78 ka. In situ corals from the Cockburn Town Reef averaged from 127 {+-} 6 to 138 {+-} 10 ka, correlating well with OIS 5e. Ages from the Reef's rubble zones hint that some coral reefs grew as early as OIS 7, but were likely reworked during OIS 5. San Salvador preserves deposits from three mid to late Quaternary highstands above, and as many as three that closely approach, modern sealevel.

  20. Associations «autochtones» de bivalves et interprétation paléoécologique dans le Jurassique supérieur Crétacé basal de la formation La Caja dans le Cañón de San Matías (Zacatecas, Mexique).

    Science.gov (United States)

    De la Mora, Alejandra; Olóriz, Federico; González-Arreola, Celestina

    2000-12-01

    The present research approaches the precise palaeoecologic interpretation based on the recognition of 12 'autochthonous' bivalve assemblages among 52 registered from the Upper Jurassic-Lowermost Cretaceous La Caja Formation in the Cañón de San Matías section (Mexican Altiplano). Fine-grained deposits together with the near-exclusive record of suspension-feeders are considered the evidence for low-energy and nutrient-rich environments. The presence of oxygen-dependent bivalves, mainly Buchia and Lucina, supports the interpretation of oxygenation as a major factor controlling ecology and therefore the composition of the 'autochthonous' bivalve assemblages studied. Significant changes in the composition of bivalve assemblages show no relation between fluctuations in ecological factors and background depositional conditions.

  1. 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

  2. Perkinsus Atlanticus – desenvolvimento de um método de diagnóstico para detecção de infecção em moluscos bivalves

    OpenAIRE

    Leite, Ricardo B.; Rodrigues, Pedro; Elandalloussi, Laurence M; Afonso, Ricardo; Nunes, Patrícia A.; Cancela, Leonor

    2003-01-01

    Diferentes espécies do género Perkinsus, um protozoário parasita pertencente ao novo phylum Perkinsea, podem ser encontradas mundialmente e constituem uma séria ameaça aos moluscos bivalves como as ostras, amêijoas, abalones e vieiras, os quais têm um papel importante não só do ponto de vista comercial, mas também ecológico.

  3. 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

  4. 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

    Energy Technology Data Exchange (ETDEWEB)

    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

  5. Probing the Climate of the Western Pacific Warm Pool During a Perturbed Thermohaline Circulation (10-60 Ka) Using Oxygen Isotopes From Long Lived Fossil Bivalves

    Science.gov (United States)

    Welsh, K. J.; Elliot, M.; Chappell, J.

    2005-12-01

    The last glacial climate was punctuated by a number of abrupt climatic events: the Heinrich Events. These are associated with reduced North Atlantic Deep Water (NADW) formation, rises in sea level of between 10 and 30m and are known to have had global climatic impacts. These rises in sea level created accommodation space for coral reefs to grow vertically. In Papua New Guinea, rapid uplift along the coast of the Huon Peninsula (up to 4m/ 1000 years) has caused these reefs to be uplifted and sub-aerially exposed. The reefs have been extensively dated and some of the reefs have been shown to be coeval with Heinrich Events. Therefore, these terraces present unprecedented opportunities to investigate the climate of the Western Warm Pool during a reduced NADW formation. The reefs at Huon contain abundant, well preserved Tridacna sp. which can be found in their growth position over grown with coral. Tridacna sp. are long lived (10-60 years) reef dwelling bivalves. They secrete aragonite in annual growth bands which, unlike corals, have been shown to precipitate in isotopic equilibrium with sea water, and in consequence are excellent recorders of average climate in palaeo-reefs. Here we present records of oxygen isotopes obtained from a set of 30 fossil Tridacna sp. found in their growth position in the uplifted fossil terraces at Huon Peninsula. Oxygen isotopes of these fossil bivalves reflect temperature, the evaporation/ precipitation balance of the water in which it is precipitated and is also affected by sea level at the time of deposition. Studies of modern climate show that temperature and precipitation increase and decrease together over the seasonal and inter-annual cycle. The samples were dated using radiocarbon dating. XRD measurements and SEM imagery were used to test for diagenesis. Oxygen isotope ratios were measured from powdered samples milled across the growth banding of the clams, which represent average conditions of temperature and salinity during the

  6. 核/双壳医用磁性微球的研制%The Preparation of Medical Nucleonic/bivalve Magnetic Microsphere

    Institute of Scientific and Technical Information of China (English)

    苑星海; 林穗云

    2012-01-01

    用共沉淀法制备Fe304磁性粒子,选用聚乙二醇和琼脂制备核/双壳医用磁性微球.最佳工艺条件为:Fe2+/Fe2+之比在1.70~1.75;沉淀剂25%NH3·H2O过量20~30%,在温度35℃,pH值11,反应时间为1h;琼脂的包覆最佳温度为50℃,pH值为9,时间lh;聚乙二醇包裹最佳温度为55℃,pH值为4,时间1h,可以通过调节搅拌速度和超声波分散时间控制Fe3O4粒子的尺度,实验确定包覆剂用量.并用透射电镜、分光光度计、古埃磁天平等进行了初步表征.%Fe3O4 magnetic microsphere was prepared by coprecipitation method and medical nucleonic/bivalve mag- netic microsphere was prepared by polyethylene glycol or agar. The optimal condition of prepared Fe3O4 magnetic microsphere was that the ratio of Fe3+/Fe2+ was between 1.70 20 -30%, and the reaction time was lh at 35℃, and pH ic/bivalve magnetic microsphere was that the coating time time with polyethylene glycol was lh at 55℃, pH with 4. and 1.75; 25% NH3 H2O precipitant was above value was 11. The optimal condition of medical nucleon- with agar was lh at 50℃, pH with 9, and the coating The size of Fe3O4 was controlled by stirring speed and ul- trasonic. The characterizations of materials were investigated by projection electron microscopy, spectrophotometer and magnetic balance.

  7. Dose preparatória de atracúrio: aferição da fadiga no músculo orbicular do olho e condições de intubação orotraqueal Dosis preparatoria de atracurio: comparación de la fatiga en el músculo orbicular del ojo y condiciones de intubación orotraqueal Priming dose of atracurium: measuring orbicularis oculi muscle fade and tracheal intubation conditions

    Directory of Open Access Journals (Sweden)

    Giovani de Figueiredo Locks

    2003-12-01

    és de un minuto. Fue considerada fatiga clínicamente importante la relación T4/T1 inferior a 0,9. RESULTADOS: Ningún paciente presentó fatiga durante el intervalo de monitorización. En 80% y 69% de los pacientes de G1 ó G2, respectivamente, las condiciones de intubación traqueal fueron consideradas clínicamente aceptables (p > 0,05. CONCLUSIONES: La dosis preparatoria de atracúrio (0,02 mg.kg-1 no causa fatiga en el músculo orbicular del ojo y no hay diferencia entre esperar 5 ó 7 minutos como intervalo entre las dosis del bloqueador neuromuscular.BACKGROUND AND OBJECTIVES: The priming principle consists of administering a low neuromuscular blocker dose, minutes before the total dose for tracheal intubation, to shorten non-depolarizing blockers onset. There is, however, the risk for muscle fade and bronchoaspiration. Laryngeal muscles are of especial interest for tracheal intubation maneuvers and airway protection. Since their direct monitoring imposes technical difficulties, it has been reported that orbicularis oculi correlates with laryngeal muscles in terms of sensitivity to neuromuscular blocks. This study aimed at evaluating the presence of orbicularis oculi muscle fade after priming atracurium dose and at comparing clinical tracheal intubation conditions after two priming dose intervals. METHODS: Participated in this study 35 adult patients, physical status ASA I or II, without risk factors for bronchoaspiration and submitted to elective surgeries. General anesthesia was induced with alfentanil and propofol and patients were manually ventilated under mask. Surface electrodes were then positioned on the temporal branch of the facial nerve, and the acceleration transducer was placed on the orbicularis oculi. Priming atracurium dose (0.02 mg.kg-1 was administered and T4/T1 ratio was evaluated every minute during 5 minutes in 20 cases (G1 and during 7 minutes in 13 cases (G2. After this interval, complementary atracurium dose (0.5 mg.kg-1 was administered

  8. 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

  9. Cloning of a big defensin gene and its response to Vibrio parahaemolyticus challenge in the noble scallop Chlamys nobilis (Bivalve: Pectinidae).

    Science.gov (United States)

    Yang, Jianqing; Luo, Jiafu; Zheng, Huaiping; Lu, Yeqing; Zhang, Hongkuan

    2016-09-01

    The noble scallop Chlamys nobilis has been an important marine cultured bivalve in the Southern Sea of China for decades. However, large-scale mortality events often occurred during the scallop' cultivation. As one of AMPs (antimicrobial peptides), big defensin is an important component of the innate immunity against pathogenic microorganisms in invertebrates. In order to investigate whether the big defensin can play a role in the immune defense against pathogenic microorganisms in noble scallop, a big defensin gene from the hemocytes of Chlamys nobilis (CnBD) was cloned, and the mRNA level was measured after an acute Vibrio parahaemolyticus challenge of 36 h. The CnBD cDNA contains an open reading frame (ORF) of 381 bp encoding a peptide of 126 amino acids residues. The deduce amino acid sequence of CnBD shows a high similarity with that from Argopecten irradians and displays common features of big defensin, indicating that CnBD is a new member of the big defensin family. Compared with the control group, the relative mRNA level of CnBD was significantly up-regulated at 3, 24 and 36 h. The present result indicated that CnBD played an immune role against bacterial infection in noble scallop. PMID:27474446

  10. 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.

  11. 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

  12. 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.

  13. 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

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. Temporal variability of the bivalve Erodona mactroides BOSC, 1802 during and after the El Niño phenomenon (2002/2003 in a subtropical lagoon, southern Brazil Variabilidade temporal do bivalve Erodona mactroides BOSC, 1802 durante e após o fenômeno El Niño (2002/2003 em uma laguna subtropical, sul do Brasil

    Directory of Open Access Journals (Sweden)

    Leonir André Colling

    2010-12-01

    Full Text Available AIM: The aim of this work was to study the relationships between temporal variability of Erodona mactroides and abiotic parameters of the water column and the substrate in a shallow embayment of the Patos Lagoon estuarine region in southern Brazil; METHODS: Samples were taken with a PVC corer (10 cm diameter buried 10 cm into the sediment between October 2002 and December 2004. Each month 18 biologic samples were taken, six substrate samples were analyzed for sediment grain size and organic matter content and sediment deposition rates were determined by 12 sediment traps every two weeks. Salinity, water temperature, water level and estuarine freshwater discharge were measured daily. Abiotic parameters and bivalve densities were tested among months with registered mortality events by ANOVA (One-way, p = 0.05, being the E. mactroides seasonal variability tested by Kruskal-Wallis (p = 0.05. Regression analyses among abiotic parameters and Spearman's "R" correlation analyses between biological and environmental data were both performed; RESULTS: Two periods were identified with distinct features: one at the beginning of the study when observed limnetic conditions in the estuarine region were caused by the ENSO - El Niño 2002/2003 phenomenon when an absence of E. mactroides was registered as well as a higher percentages of fine sediments and lower percentages of organic matter. The second period was characterized by a decreasing influence of the El Niño and predominance of mixohaline conditions, recruitments and increasing densities of E. mactroides with a successive decrease of mean densities due to three mortality events, lower percentages of fine sediments and higher percentages of organic matter; CONCLUSIONS: The present study provides evidences that the occurrence of E. mactroides in the southern estuarine region depends on the water flow regime from the drainage basin, which characterizes species recruitment as temporally unpredictable and

  1. Characteristics of bivalve diversity in typical habitats of China seas%中国海典型生境双壳类软体动物多样性特点

    Institute of Scientific and Technical Information of China (English)

    徐凤山; 张均龙

    2011-01-01

    中国海域广阔、海岸线绵长、环境复杂、包含的生境多样,对中国海典型生境中双壳类软体动物多样性的分析,可以反映中国海双壳类软体动物的区系特点.作者根据多年的研究成果和国内外贝类学家的报道,对不同典型生境的双壳类软体动物的多样性特点、生活环境、生态习性进行了阐述,对不同海区的双壳类软体动物的分布特点进行了分析.由于沿岸水、冷水团及黄海暖流的影响,黄海的区系组成最为复杂:受台湾暖流和黑潮暖流的影响,东海的多样性呈现出随纬度降低、离岸越远,暖水种增加且暖水性增强的特点;南海由于南部濒临赤道,北部属亚热带,存在珊瑚礁、红树林、海草场等多种生境,其多样性最高.到目前为止,中国海的双壳类软体动物共记录有1,104种,分属于77科393属,其中渤海有68属87种,黄海121属175种,东海195属337种,南海的种类最多,297属822种.%With vast sea areas, long coastline and complex environmental conditions, the China seas contain various habitats for bivalves. The diversity characteristics of some typical habitats can reflect the molluscan fauna of China seas. Based on our years of work and records from malacologists home and abroad, the bivalve diversity, habitats and ecological habits in different environments are described, and the distribution characters in different sea areas are analysed. Due to the effects of coastal water, Yellow Sea Cold Water Mass and Yellow Sea Warm Current, faunal elements in Yellow Sea are the most complex. Most of the species in East China Sea are subtropical elements, and the warm water species increases with the decrease of latitude and distance from coast, because of the hydrological characters of Kuroshio Warm Current and Taiwan Warm Current. The south part of the South China Sea is close to the equator and the north part is subtropical, with many special habitats, such as, coral reefs

  2. Analgesic-antiinflammatory drugs inhibit orbicularis oculi reflexes in humans via a central mode of action.

    Science.gov (United States)

    Ferracuti, S; Leardi, M G; Cruccu, G; Fabbri, A; Itil, T M

    1994-01-01

    1. A cross-over single blind study examined the possible central effects of non-opioid analgesic drugs on the trigeminal reflexes. 2. The corneal reflex and blink reflex (R1, R2) were recorded electromyographically and response areas measured in healthy volunteers before and after intramuscular injection of piroxicam (40 mg); and after intravenous injection of lysine acetylsalicylate (500 mg). After the last drug recording the subjects received intravenous naloxone (2 mg) followed 5 minutes later by further reflex testing. Saline was used as a placebo in control experiments. 3. Both analgesics reduced the corneal reflex: piroxicam induced a 27% and lysine acetylsalicylate a 21% a reduction that naloxone did not reverse. Neither drug reduced the early or the late component of the blink reflex. 4. The marked inhibitory changes that the two non-narcotic analgesics produced on the corneal reflex--a nociceptive response--indicate a centrally-mediated action. 5. Naloxone's failure to reverse the induced analgesia argues against opiate receptor mediation. PMID:8115666

  3. Analgesic-antiinflammatory drugs inhibit orbicularis oculi reflexes in humans via a central mode of action.

    Science.gov (United States)

    Ferracuti, S; Leardi, M G; Cruccu, G; Fabbri, A; Itil, T M

    1994-01-01

    1. A cross-over single blind study examined the possible central effects of non-opioid analgesic drugs on the trigeminal reflexes. 2. The corneal reflex and blink reflex (R1, R2) were recorded electromyographically and response areas measured in healthy volunteers before and after intramuscular injection of piroxicam (40 mg); and after intravenous injection of lysine acetylsalicylate (500 mg). After the last drug recording the subjects received intravenous naloxone (2 mg) followed 5 minutes later by further reflex testing. Saline was used as a placebo in control experiments. 3. Both analgesics reduced the corneal reflex: piroxicam induced a 27% and lysine acetylsalicylate a 21% a reduction that naloxone did not reverse. Neither drug reduced the early or the late component of the blink reflex. 4. The marked inhibitory changes that the two non-narcotic analgesics produced on the corneal reflex--a nociceptive response--indicate a centrally-mediated action. 5. Naloxone's failure to reverse the induced analgesia argues against opiate receptor mediation.

  4. New method for the analysis of lipophilic marine biotoxins in fresh and canned bivalves by liquid chromatography coupled to high resolution mass spectrometry: a quick, easy, cheap, efficient, rugged, safe approach.

    Science.gov (United States)

    Rúbies, A; Muñoz, E; Gibert, D; Cortés-Francisco, N; Granados, M; Caixach, J; Centrich, F

    2015-03-20

    A new method for the analysis of lipophilic marine biotoxins (okadaic acid, dinophysistoxins, azaspiracids, pectenotoxins, yessotoxins, spirolids) in fresh and canned bivalves has been developed. A QuEChERS methodology is applied; i.e. the analytes are extracted with acetonitrile and clean-up of the extracts is performed by dispersive solid phase extraction with C18. The extracts are analyzed by ultra-high performance liquid chromatography coupled to a hybrid quadrupole-Orbitrap mass spectrometer, operating in tandem mass spectrometry mode, with resolution set at 70,000 (m/z 200, FWHM). Separation of the analytes, which takes about 10min, is carried out in gradient elution mode with a BEH C18 column and mobile phases based on 6.7mM ammonia aqueous solution and acetonitrile mixtures. For each analyte the molecular ion and 1 or 2 product ions are acquired, with a mass accuracy better than 5ppm. The quantification is performed using surrogate matrix matched standards, with eprinomectin as internal standard. The high-throughput method, which has been successfully validated, fulfills the requirements of European Union legislation, and has been implemented as a routine method in a public health laboratory.

  5. Study on Sterility Test after Using Non-PVC Bivalve Soft-bag Injection in PIVAS%PIVAS使用非PVC双阀软袋包装输液后的无菌检查研究

    Institute of Scientific and Technical Information of China (English)

    朱慧娟; 黄蔚茹; 张胜安; 李荣; 张爱玲; 高巍; 李艳玲

    2016-01-01

    目的:研究静脉药物集中调配中心(PIVAS)使用非PVC双阀软袋包装输液后的无菌检查情况.方法:按照输液的包装类型和配制环境将试验分为3组,每组320份.第1组采用非PVC双阀软袋葡萄糖液,于PIVAS配制;第2组采用非PVC双阀软袋葡萄糖液,于病区配制;第3组采用塑瓶葡萄糖液,于病区配制.穿刺1、3、6、9次后将输液成品(n=80)分别放置在病区环境中0、2、4、6 h(n=20),按照2010版《中国药典》(二部)无菌检查法项下薄膜过滤法进行无菌检查,并分析3组输液穿刺9次时的污染情况.结果:第1组无菌生长,第2、3组阳性检出率分别为2.5%和3.8%(n=320);穿刺1、3、6、9次后各组总的阳性检出率分别为0、0.4%、0.4%、7.5%(n=240),第1组阳性检出率均为0(n=80),第2组分别为0、1.25%、0、8.75%(n=80),第3组分别为0、0、1.25%、13.75%(n=80);穿刺9次时分别放置0、2、4、6 h后第1组的阳性检出率均为0(n=20),第2组分别为25%、5%、0、5%(n=20),第3组分别为5%、15%、5%、30%(n=20).结论:在PIVAS使用非PVC双阀软袋输液可有效预防微生物污染.%OBJECTIVE:To study sterility test after using Non-PVC bivalve soft-bag injection in PIVAS. METHODS:The test was divided into 3 groups according to the type of transfusion solution packaging and dispensing environment. Group 1 received Glucose solution using bivalve soft-bag,dispensed in PIVAS;group 2 received Glucose solution using bivalve soft-bag,dispensed in wards area;group 3 received Glucose solution using plastic bottle,dispensed in wards area. After puncturing 1,3,6,9 times (n=80),finished products placed in ward for 0,2,4,6 h(n=20),and then sterility test was conducted with membrane filtra-tion method stated in second part of Chinese Pharmacopoeia (2010 edition). Infusion contamination of 3 groups was analyzed at 9th puncture. RESULTS:The growth of bacteria was not found in group 1;the positive detection rate of group 2 and 3 were 2.5%and 3

  6. New method for the analysis of lipophilic marine biotoxins in fresh and canned bivalves by liquid chromatography coupled to high resolution mass spectrometry: a quick, easy, cheap, efficient, rugged, safe approach.

    Science.gov (United States)

    Rúbies, A; Muñoz, E; Gibert, D; Cortés-Francisco, N; Granados, M; Caixach, J; Centrich, F

    2015-03-20

    A new method for the analysis of lipophilic marine biotoxins (okadaic acid, dinophysistoxins, azaspiracids, pectenotoxins, yessotoxins, spirolids) in fresh and canned bivalves has been developed. A QuEChERS methodology is applied; i.e. the analytes are extracted with acetonitrile and clean-up of the extracts is performed by dispersive solid phase extraction with C18. The extracts are analyzed by ultra-high performance liquid chromatography coupled to a hybrid quadrupole-Orbitrap mass spectrometer, operating in tandem mass spectrometry mode, with resolution set at 70,000 (m/z 200, FWHM). Separation of the analytes, which takes about 10min, is carried out in gradient elution mode with a BEH C18 column and mobile phases based on 6.7mM ammonia aqueous solution and acetonitrile mixtures. For each analyte the molecular ion and 1 or 2 product ions are acquired, with a mass accuracy better than 5ppm. The quantification is performed using surrogate matrix matched standards, with eprinomectin as internal standard. The high-throughput method, which has been successfully validated, fulfills the requirements of European Union legislation, and has been implemented as a routine method in a public health laboratory. PMID:25687456

  7. 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

  8. 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.

  9. Saxitoxin analysis in bivalve molluscs. Seafoodplus Traceability

    OpenAIRE

    Etienne, Monique

    2006-01-01

    Paralytic shellfish poisoning (PSP) is caused by consumption of a wide variety of shellfish which accumulated saxitoxins (STXs) from marine dinoflagellates (Alexandrium minutum, A. tamarense, Gymnodinium catenatum, Pyrodinium bahamense) and affect a wide variety of shellfish. There are about 20 saxitoxin analogs with closely related structures. A regulatory level of 0.8 mg/kg shellfish meat as STX equivalents has existed in North America and Europe for many years. The methods of determination...

  10. Histological techniques for marine bivalve molluscs: update

    OpenAIRE

    Kim, Y.; Ashton-Alcox, K.A.; Powell, E.N.

    2006-01-01

    This chapter describes the procedures for determining the reproductive stage of oysters, mytilid mussels, and dreissenid mussels collected for NOAA’s National Status and Trends Mussel Watch Project. Analyses are conducted on paraffin-embedded tissues sectioned at a 5-μm thickness and stained using a pentachrome staining procedure. Each slide is examined microscopically to determine the animal’s sex and stage of gonadal development. A semi-quantitative ranking is assigned.

  11. Ecotoxicology of marine biotoxins in bivalve shellfish

    OpenAIRE

    McCarthy, Moira

    2013-01-01

    A small proportion of harmful algae produce toxins which are harmful to human health. Strict monitoring programmes are in place within Ireland and the EU to effectively manage risk to human consumers of shellfish species that have accumulated marine biotoxins in their tissues. However, little is known about the impacts of HABs on shellfish health. This study used Solid Phase Adsorption and Toxin Tracking (SPATT) for the passive sampling of algal biotoxins at Lough Hyne Marine Nature Reserve i...

  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. A Biomechanical Modeling Study of the Effects of the Orbicularis Oris Muscle and Jaw Posture on Lip Shape

    Science.gov (United States)

    Stavness, Ian; Nazari, Mohammad Ali; Perrier, Pascal; Demolin, Didier; Payan, Yohan

    2013-01-01

    Purpose: The authors' general aim is to use biomechanical models of speech articulators to explore how possible variations in anatomical structure contribute to differences in articulatory strategies and phone systems across human populations. Specifically, they investigated 2 issues: (a) the link between lip muscle anatomy and variability in…

  14. Fear-potentiated startle processing in humans: Parallel fMRI and orbicularis EMG assessment during cue conditioning and extinction.

    Science.gov (United States)

    Lindner, Katja; Neubert, Jörg; Pfannmöller, Jörg; Lotze, Martin; Hamm, Alfons O; Wendt, Julia

    2015-12-01

    Studying neural networks and behavioral indices such as potentiated startle responses during fear conditioning has a long tradition in both animal and human research. However, most of the studies in humans do not link startle potentiation and neural activity during fear acquisition and extinction. Therefore, we examined startle blink responses measured with electromyography (EMG) and brain activity measured with functional MRI simultaneously during differential conditioning. Furthermore, we combined these behavioral fear indices with brain network activity by analyzing the brain activity evoked by the startle probe stimulus presented during conditioned visual threat and safety cues as well as in the absence of visual stimulation. In line with previous research, we found a fear-induced potentiation of the startle blink responses when elicited during a conditioned threat stimulus and a rapid decline of amygdala activity after an initial differentiation of threat and safety cues in early acquisition trials. Increased activation during processing of threat cues was also found in the anterior insula, the anterior cingulate cortex (ACC), and the periaqueductal gray (PAG). More importantly, our results depict an increase of brain activity to probes presented during threatening in comparison to safety cues indicating an involvement of the anterior insula, the ACC, the thalamus, and the PAG in fear-potentiated startle processing during early extinction trials. Our study underlines that parallel assessment of fear-potentiated startle in fMRI paradigms can provide a helpful method to investigate common and distinct processing pathways in humans and animals and, thus, contributes to translational research.

  15. Taste Evaluation of Non-volatile Taste Compounds in Bivalve Mollusks from Beibu Gluf, Guangxi%广西北部湾3种贝类中主要呈味物质的测定及呈味作用评价

    Institute of Scientific and Technical Information of China (English)

    陈德慰; 苏键; 刘小玲; 颜栋美; 林莹

    2012-01-01

    Major non-volatile taste active compounds in oyster (Crassostrea rivularis), clam (Meretrix meretrix) and paphia (Paphia undulata) were determined, which included free amino acids, nucleotides and so on. Taste impact of the main non-volatile taste compounds were evaluated by taste active value (TAVs) methods; umami intensity of bivalve mollusks were evaluated by equivalent umami concentration (EUC) methods. The EUC were oyster (3.2 g MSG/100 g meat), clam (1.9 g MSG/100 g meat) and paphia (2.7 g MSG/100 g meat), respectively. TAVs of all EUC were great than one, which meant they contributed to the strong umami taste of oyster, clam and paphia.%测定广西北部湾牡蛎(Crassostrea rivularis)、文蛤(Meretrix meretrix)和波纹巴非蛤(Paphia undulata)3种贝类中的呈味核苷酸(AMP、GMP、IMP)、糖原等非挥发性呈味物质的含量,并采用味道强度值和等价鲜味值(或味精当量)评价这些非挥发性呈味物质的呈味作用鲜味强度。结果表明:牡蛎、文蛤和波纹巴非蛤的味精当量分别为3.2、1.9、2.7g MSG/100g,对应的味精当量的味道强度值分别是106.7、63.3、90,均远大于1,是其呈强烈鲜味的主要原因。

  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. 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

  18. Genetic improvement of hatchery propagated bivalve stocks : prospects and constraints

    OpenAIRE

    Boudry, Pierre

    2005-01-01

    To date, the most significant genetic improvement for the production of Pacific oyster (Crassostrea gigas) has been obtained through the production of triploids, especially since the development of tetraploids. Quantitative genetics studies suggest that significant gains, for disease resistance or other traits, could be obtained in diploids. However, the limited extent of hatchery-propagation (versus natural recruitment) and/or various technical difficulties and biological characteristics of ...

  19. 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.

    into four cationic and six anionic isoenzymes using the polybuffer e x changers 118 and 94, respectively. Their p I values ranged from 5.4 to 9.2. On electrophoresis, the testis GSTs showed identical subunit pattern to that of brain, i.e. Yc, Yb, Y b... and in various organs like liver, kidney, intestine, brain and testis. They occur in the cytoplasm, membranes of mitochondria, micr o somes and nuclei 3 . Each organ possesses a unique profile of GSTs, the liver and testis having the high GST activity in r...

  20. 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

    and the antioxidant system, as also damage to genetic material. This could be used as potential biomarker to measure pollution stress in animals. While extensive work on biomarker research is being undertaken in several parts of the world, such studies are yet...

  1. Relationships between innate immunity in bivalve molluscs and environmental pollution

    OpenAIRE

    MI Girón-Pérez

    2010-01-01

    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.

  2. 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...

  3. 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,...

  4. 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.

  5. SURVIVAL ESTIMATES OF BYCATCH INDIVIDUALS DISCARDED FROM BIVALVE DREDGES

    OpenAIRE

    Francisco Leitão; Pedro Range; Miguel Baptista Gaspar

    2014-01-01

    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 d...

  6. 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.

  7. Radionuclide concentrations in bivalves collected along the coastal United States

    International Nuclear Information System (INIS)

    In 1990, the National Oceanic and Atmospheric Administration's National Status and Trends Program initiated a study of artificial radionuclides (241Am, 239+240Pu, 238Pu, 137Cs, 110Ag, 90Sr, 65Zn, 60Co, and 58Co) in oysters and mussels collected along the coastal US. The results of this study show that activation products 110Ag, 65Zn, 60Co and 58Co are sometimes present close to nuclear facilities. In addition, based on a nonparametric Kruskal-Wallis statistical test, it appears that 241Am and 137Cs concentrations as well as 241Am/239+240Pu and 137Cs/40K activity ratios are highest along the West Coast of the US. For 238Pu, 239+240Pu, and 90Sr activities and the other ratios, the differences observed in the distribution of the radionuclides between the various coasts are not statistically significant. There is also a statistical difference between the values of the 239+240Pu/90Sr ratio in oysters vs mussels collected along the East Coast and of the 241Am/239+240Pu ratio between two species of mussels collected along the West Coast. Finally, when the NOAA results for 241Am, 239+240Pu, and 137Cs are compared with those of an earlier (1976-1978) Mussel Watch Program sponsored by the Environmental Protection Agency, the statistical Sign Test generally shows a significant decrease in the concentrations between the mid-1970s and the early 1990s. (author)

  8. Domoic acid analysis in bivalve molluscs. Seafoodplus traceability

    OpenAIRE

    Etienne, Monique

    2006-01-01

    Domoic acid (DA) was identified as the toxin responsible for an outbreak of illness in Canada in 1987, caused by eating blue mussels that had accumulated DA as a result of the presence of Pseudo-nitzschia pungens. It is named amnesic shellfish poisoning (ASP). Since a regulatory level of 20 mg DA/kg of shellfish meat was established. The methods of determination of domoic acid are reviewed: biological assays in vivo and in vitro, biochemical and chemical assays. The AOAC mouse bioassay, which...

  9. Is the European pond turtle Emys orbicularis strictly aquatic? – Habitats where the turtle lives in central Europe

    OpenAIRE

    Sławomir Mitrus

    2010-01-01

    Based on ecological characteristics and phylogenetic analysis, it is possible to try to reconstruct the evolution of ecological traits in turtles. However, the European pond turtle is treated by different scientists as aquatic or as semi-aquatic species. The importance of terrestrial behaviour for this species is discussed.

  10. 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.

  11. Histologie comparée des fosses nasales de quelques Tortues marines (Dermochelys coriacea et Chelonia mydas) et d’eaux douces (Emys orbicularis et Pseudemys scripta) (Reptilia, Dermochelyidae, Cheloniidae, Emydidae)

    NARCIS (Netherlands)

    Saint-Girons, H.

    1991-01-01

    Comparative histological studies carried out on the nasal cavity of four species of turtles showed that the sea turtles have a more or less regressed olfactive epithelium compared to that of the Emydidae but that their vomeronasal epithelium is more developed. The location of the vomeronasal epithel

  12. 眼轮匝肌瓣在睑袋手术中矫治泪沟畸形的应用%Application of orbicularis oculi musculus flap in correction of tear trough deformity in blepharoplasty

    Institute of Scientific and Technical Information of China (English)

    张翰理; 阮庆玲; 吴文兵; 余曼利; 钟书霞; 应胜华

    2014-01-01

    目的:介绍睑袋成形术中利用眼轮匝肌矫正泪沟畸形的方法.方法:在常规睑袋成形术中,利用切下的眼轮匝肌组织瓣,平铺于泪沟凹陷处的骨膜上,适当固定,填充泪沟局部凹陷,达到平坦,过渡自然的外观.结果:本组共施行手术71例,术后随访3~21个月,泪沟畸形及睑袋畸形、睑颊沟显现等体征均得以矫正,中面部较术前明显年轻,无下睑凹陷、外翻或巩膜过分显露、睑球分离等并发症发生,效果满意.结论:利用眼轮匝肌瓣法矫治泪沟畸形的睑袋成形术操作简单、设计合理,适用于修复伴有泪沟、睑颊沟显现且眶隔脂肪不多的睑袋求美者.

  13. 防止中、老年眼袋整形术下睑外翻的技巧%A technique in preventing lower eyelid ectropin in fascia ligament of museuli orbicularis in middle aged and old - aged

    Institute of Scientific and Technical Information of China (English)

    杨平; 帅淑华

    2003-01-01

    目的防止眼袋整形术下睑外翻并发症.方法行中、老年眼袋整形手术2 0例,总结出在眼袋整形手术中,在手术方法上应重点注意切皮的适量等技巧.结果手术20例,其中5例手术后发现轻微睑球分离,拆线后恢复尚可,余15例效果明显改善.结论通过对2 0例中、老年眼袋整形术的手术体会,总结出在手术方法上,应重点注意去皮、去眼轮匝肌、去眶脂,提紧眶肌筋膜韧带方面的操作技巧,注意手术技巧,可降低下睑外翻的发生率.

  14. Gynogenetic induction in marine bivalve molluscs for improvement of stocks: Standardization of some important factors

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, U.

    with 20 x 10 super(6) per ml concentration so as to effectively inseminate 2000-2500 eggs in 50 ml of seawater. The results of the preliminary gynogenetic induction experiments performed ascertained the reliability of these parameter limits. In controls...

  15. Comparative feeding on chlorophyll - rich versus remaining organic matter in bivalve shellfish

    NARCIS (Netherlands)

    Hawkins, A.; Pascoe, P.L.; Parry, H.; Brinsley, M.; Cacciatore, F.; Black, K.; Fang, J.; Smaal, A.C.

    2013-01-01

    Filter feeding was compared in the blue mussel Mytilus edulis, Mediterranean mussel Mytilus galloprovincialis, Pacific oyster Crassostrea gigas, Chinese pleated oyster Crassostrea plicatula, Chinese scallop Chlamys farreri,Manila clam Tapes phillipinarum, razor clam Sinonvacula constricta, and blood

  16. 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.

  17. 76 FR 65200 - Risk Assessment on Norovirus in Bivalve Molluscan Shellfish: Request for Comments and for...

    Science.gov (United States)

    2011-10-20

    ..., Norovirus Technical Fact ] Sheet, http://www.cdc.gov/ncidod/dvrd/revb/gastro/norovirus-factsheet.htm . 2... Activities, http://www.cdc.gov/ncidod/dvrd/revb/gastro/norovirus-surv-disease-burden.htm . 3....

  18. The effects of cadmium of the growth and metallothionein expression of the bivalve larvae, crassostrea virginica

    Energy Technology Data Exchange (ETDEWEB)

    Craig, K.D. [Univ. of Charleston, WV (United States); Burnett, K.; Ringwood, A.; MacDougal, K.; Kendall, L.

    1994-12-31

    Oyster larvae, Crassostrea virginica, were exposed to 20 ppb of cadmium (Cd) and fed (mixture of Isochrysis galbana & Chaetoceros gracilis, 40mL) in the laboratory for 10 days. On the 0, 4, 7 and 10 day the larvae samples were taken and frozen. Then they were homogenized, centrifuged, ultrafiltered through a membrane separation technique used to segregate substances according to the molecular weight and size. The cytosolic protein was first partially purified by gel permeation, then by PAGE (Polyacrylamide Gel Electrophoresis). The controls and metal exposed larvae were evaluated on total wet weight and the metallothioneins (MT) were identified from the preparations using silver staining techniques. No significant changes could be detected in the controls. However, there was a great number dead at the beginning of the experiment. Cd accumulation began at the time of exposure. This suggests that surface area may play a role in determining short-term accumulation rates. Cd effects on growth (wet weight) was slightly different, the exposed weighed less than or equal to the controls. In addition, the Cd uptake via food played an insignificant role compared to direct uptake from sea water. Between day 0 and 7 there was a number of mortalities for the controls and exposed. In addition, there was a major weight change with the exposed, they appeared to weigh less than the controls on day 7, whereas on day 4 they weighed more. So weight is a very sensitive indicator of toxic stress.

  19. 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...

  20. 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

  1. 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.

    of byssus in samples could lead to considerable variation in iron content. All animals were purged for 48 h prior to prepara- tion for analysis as described in Brown & Holley (1982); analytical techniques followed the practices adopted in this paper... in mussel farming. Aquaculture 20, 291-303. Sokal, R. R. & Rohlf, E J. (1981). Biometry. W. H. Freeman and Company, San Francisco. Strong, C. R. & Luoma, S. N. (1981). Variations in the correlation of body size with concentrations of copper and silver...

  2. Population dynamics and growth of the bivalve Choromytilus meridionalis (Kr.) at different tidal levels

    Science.gov (United States)

    Griffiths, Roberta J.

    1981-01-01

    Settlement, growth and reproductive output of a population of Choromytilus meridionalis have been monitored at different shore levels at Bailey's Cottage, False Bay, South Africa. Settlement was irregular, occurring at 4- to 6-year intervals, and confined to the sublittoral and lower littoral of rocky areas. Spat settled on the existing mussel bed and adjacent clean rock surfaces. Continual migration of young mussels up the shore took place during the first 1 to 1·5 years of growth until an even distribution up to 0·5 m above L.W.S. was achieved. Juveniles displaced older individuals by moving between them and forcing them off the rocks so that the majority of the adult population were eliminated from the bed within the first year after spat settlement. Mortality in individual cohorts was largely caused by strong wave action and competition for space. The density of individuals within the mussel bed was closely related to mean shell length. Growth rates varied with habitat and declined markedly with increasing height above L.W.S. Sexual maturity was attained at approximately 20 mm and reproductive output rose from 5 kJ year -1 at this length to 80 kJ year -1 at 100 mm shell length. Since packing densities were much higher in smaller individuals the annual gamete output assessed on an area basis, remained fairly constant as the mussels grew, and averaged 1392 g m -2 year -1 dry weight (31 320 kJ m -2 year -1). Energy expended as gonad output exceeded that due to mortality by a factor of 10.

  3. Uncharted Waters: Bivalves of Midway Atoll and Integrating Mathematics into Biology Education

    Science.gov (United States)

    McCully, Kristin M.

    2013-01-01

    To protect and conserve the Earth's biodiversity and ecosystem services, it is important not only to understand and conserve species and ecosystems, but also to instill an understanding and appreciation for biodiversity and ecosystem services in the next generations of both scientists and citizens. Thus, this dissertation combines research into…

  4. Reversed optimality and predictive ecology : burrowing depth forecasts population change in a bivalve

    NARCIS (Netherlands)

    van Gils, Jan A.; Kraan, Casper; Dekinga, Anne; Koolhaas, Anita; Drent, Jan; de Goeij, Petra; Piersma, Theunis

    2009-01-01

    Optimality reasoning from behavioural ecology can be used as a tool to infer how animals perceive their environment. Using optimality principles in a 'reversed manner' may enable ecologists to predict changes in population size before such changes actually happen. Here we show that a behavioural ant

  5. 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.

  6. 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.

    -347. 12. Ekanayake P, Lee YD, Lee J. Antioxidant Activity of Flesh and Skin of Eptatretus Burgeri (Hag Fish) and Enedrias Nebulosus (White Spotted Eel). Food Sci Technol Int 2004; 10: 171-177. 13. Watanabe N, Yamamoto K, Ishikawa H, et al...

  7. Growth and production of the venerid bivalve Eurhomalea exalbida in the Beagle Channel, Tierra del Fuego

    Science.gov (United States)

    Lomovasky, Betina J.; Brey, Thomas; Morriconi, Elba; Calvo, Jorge

    2002-11-01

    Growth, mortality and productivity of the hard clam Eurhomalea exalbida from Ushuaia Bay, Beagle Channel, were investigated. The parameters of the von Bertalanffy growth function were estimated to be H ∞ = 74 mm, K = 0.18 y -1, t 0 = 0.15 y. Maximum individual production amounted to 2.74 g shell-free wet mass (SFWM) at 49.5 mm shell height. Animals between 40 mm and 70 mm shell height contributed most to overall population somatic production P of 134 g SFWM m -2 y -1. Mean annual biomass B amounted to 1123 g SFWM m -2 y -1. Annual P/B ratio and mortality rate Z were estimated to be 0.12 y -1 and 0.14 y -1, respectively. Slow growth and low turnover make this population less suitable for sustainable commercial exploitation.

  8. Growth and production of the venerid bivalve Eurhomalea exalbida in the Beagle Channel, Tierra del Fuego

    OpenAIRE

    Lomovasky, B.; Brey, Thomas; Morriconi, E.; Calvo, J.

    2002-01-01

    Growth, mortality and productivity of the hard clam E. exalbida from Ushuaia Bay, Beagle Channel were investigated. The parameters of the von Bertalanffy growth function were estimated to be H = 73.98 mm, K = 0.180 y 1, t0 = 0.147 y. Maximum individual production amounted to 2.742 g shell free wet mass (SFWM) at 49.5 mm shell height. Animals between 40 mm and 70 mm shell height contribute most to overall population somatic production P of 133.89 g SFWM m-2 y-1. Mean annual biomass B amounted ...

  9. On the evolutionary ecology of symbioses between chemosynthetic bacteria and bivalves

    NARCIS (Netherlands)

    Roeselers, G.; Newton, I.L.G.

    2012-01-01

    Mutualistic associations between bacteria and eukaryotes occur ubiquitously in nature, forming the basis for key ecological and evolutionary innovations. Some of the most prominent examples of these symbioses are chemosynthetic bacteria and marine invertebrates living in the absence of sunlight at d

  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. Bivalve Forensics: Sclerochronological Constraints on the Timing of a Biological Invasion in San Francisco Bay

    Science.gov (United States)

    Goodwin, D. H.; Cohen, A. N.; Roopnarine, P. D.

    2007-12-01

    Clams are biological chart recorders: their shells contain a record of environmental conditions in the form of periodic growth increments and geochemical variation. In most species, this archive begins with the deposition of the dissoconch following metamorphosis and ultimately ends with the death of the individual. In fossil specimens, the exact date of the beginning or end of the archive cannot be determined. Therefore, sclerochronologic and geochemical records from fossils represent short intervals of time that cannot be directly tied to absolute time--so called "floating chronologies." In contrast, the date of the end of the archive from live- collected specimens can be precisely resolved--in many cases to the day collection. Using this date as a pinning point, one can establish the timing of events throughout the remainder of the chronology relatively precisely. Here, we use this approach to constrain the timing of a biological invasion event in San Francisco Bay. The basic idea is simple. The timing of an invasion event (i.e., successful recruitment), can be resolved if the date of the initiation of shell deposition is established from the first specimens to appear in a new area. To absolutely establish the timing of an invasion, one must assume that specimens represent the initial cohort of invaders. If this assumption cannot be met, then this method provides minimum estimates for the timing of invasion events. This technique is best suited for regions where species composition is closely monitored and the likelihood of collecting the initial cohort is high. To demonstrate this technique, we examined specimens thought to represent the initial cohort of the oyster Crassostrea gigas to establish a population in South San Francisco Bay. All individuals were collected live in July or August of 2006. Sclerochronological examination suggested that the specimens were at least four years old. These age estimates were confirmed using stable oxygen isotope (δ18O) and stable carbon isotope (δ13C) variation. For each specimen, δ18O and δ13C profiles representing the complete ontogenetic history were obtained by sampling the resilifer in the left valve. In all specimens, δ18O and δ13C values were positively correlated and show strong seasonal variation. Comparison of predicted and observed δ18O variation suggests that both temperature and the δ18O of the water in which they grew--a function of Delta outflow--strongly influence the pattern of δ18O observed in the shell. Together, sclerochronological and geochemical analysis indicate that this invasion of C. gigas in South San Francisco Bay occurred in the Spring of 2002. The ability to establish the timing of a biological invasion is likely to help scientists better understand the dynamics of invasion events. Furthermore, these results may help environmental managers and policy makers manage invasive species, as well as develop strategies to prevent future invasions of C. gigas and other non- native species.

  12. 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

  13. 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.

  14. 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.

  15. Variations in retention efficiency of bivalves to different concentrations and organic content of suspended particles

    Institute of Scientific and Technical Information of China (English)

    张继红; 方建光; 梁兴明

    2010-01-01

    Retention efficiencies (RE) of scallop (Chlamys farreri),oyster (Crassostrea gigas) and mussel (Mytilus edulis) in a flow-through system were measured to understand the short-term response to various particle and organic matter concentrations.By comparing the RE of C.farreri with that of C.gigas and M.edulis,we gained further knowledge on the feeding physiological characteristics of C.farreri and ascertained the possible cause of high summer mortalities of this species.The experimental feeding conditions in...

  16. 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.

  17. 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.

  18. Antioxidant defences role during post anoxic recovery in bivalve mollusc Scapharca inaequivalvis

    Directory of Open Access Journals (Sweden)

    J. Foschi

    2011-01-01

    Full Text Available Euryoxic organisms are able to withstand hypoxic conditions until the restoration of normal O2 levels, when the re-introduction of oxygen causes a decisive burst in reactive oxygen species (ROS. The consequent oxidative damage is countered by defence systems constituted by antioxidant enzymes, such as SOD, CAT, Se-GPx and G6PDH. Specimens of Scapharca inaequivalvis were exposed to anoxia for 3, 6 and 24 hours and subsequent reoxygenation for 1, 3, 5 and 24 hours. It has been investigated SOD, CAT, Se-GPx and G6PDH activity and MnSOD and CuZnSOD expression in the digestive gland. The results showed SODs activity to be high during both anoxia and reoxygenation. CAT and Se-GPx increase significantly overall during recovery. Only CuZnSOD expression was greater after 6 and 24 hours of anoxia. The presence of high levels of antioxidant enzymes during anozia suggests that the response of S. inaequivalvis is typical of euryoxic animals and represents an interesting model for studying the processes of ischaemia/reperfusion in mammals.

  19. The effect of polluted sediment on the gonadal development and embryogenesis of bivalves

    NARCIS (Netherlands)

    Timmermans, B.M.H.; Hummel, H.; Bogaards, R.H.

    1996-01-01

    Cockles (Cerastoderma edule) and Baltic clams (Macoma balthica) were kept on polluted sediment from the harbour of Rotterdam, and on clean sediment from the Wadden Sea (control). Their gametogenesis was then followed. In vitro fertilisation (IVF) experiments were carried out and larvae were cultured

  20. 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. PMID:27394812

  1. 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.

  2. Interactions of a pesticide/heavy metal mixture in marine bivalves: a transcriptomic assessment

    OpenAIRE

    Boatti Lara; Negri Alessandro; Banni Mohamed; Dondero Francesco; Dagnino Alessandro; Viarengo Aldo

    2011-01-01

    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 pol...

  3. 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...

  4. 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...

  5. Toxicité des sédiments. Test sur les embryons de bivalves

    OpenAIRE

    Goraguer, Herle; Toularastel, France

    1999-01-01

    Mytilus early development biossays have been used for sediment toxicity testing in the coastal zone heavily contaminated by the river Seine. This bioassays have been realized from fecundation to "D" larval stage in presence of sediment aqueous extracts. Results exhibit a high variability wich could not be related to any geographical gradient, probably due to a large effect on variance of seasonal variations.

  6. 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

  7. 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.

  8. 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 upta...

  9. Pearl mussels (Margaritifera marocana) in Morocco: Conservation status of the rarest bivalve in African fresh waters.

    Science.gov (United States)

    Sousa, Ronaldo; Varandas, Simone; Teixeira, Amílcar; Ghamizi, Mohamed; Froufe, Elsa; Lopes-Lima, Manuel

    2016-03-15

    Margaritifera marocana is one of the rarest freshwater mussel species (listed as critically endangered), and is endemic to Morocco. Despite its constrained distribution and low abundance, to date there are no quantitative studies addressing the conservation status of this species. Surveys were conducted in 36 sites along the Oum Er Rbia river basin (Rivers Derna, Laabid and Oum Er Rbia) to assess the distribution, abundance, population structure and genetic diversity of M. marocana. Just one specimen was found on River Oum Er Rbia and none on River Derna; however, a high abundance was found in the lower section of River Laabid (e.g., site Laabid 6 reached a mean density of 11.0 ± 6.8 ind.m(-2)). Contrary to earlier information, which reported an overall population size fewer than 250 individuals in a restricted area and no juvenile presence, this study showed that a much higher abundance exists in River Laabid alone. In addition, the species is present in more than 50 km of this river and is still recruiting since small specimens were found. Regarding genetic diversity, six of nine loci previously used in Margaritifera margaritifera were polymorphic and suitable in M. marocana. The spatial range contraction of this species is likely to be very recent, since no strong signature was detected by the molecular diversity indices. Information gathered in this study can be used as a reference to the present conservation status of M. marocana, and guide future research and management initiatives to better conserve it. We conclude discussing the potential major threats for the future survival of M. marocana and suggest some management measures (and research needs) that should be urgently applied. PMID:26789376

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. The clam (Chamelea gallina: evaluation of the effects of solids suspended in seawater on bivalve molluscs

    Directory of Open Access Journals (Sweden)

    Salvatora Angela Angioni

    2010-03-01

    Full Text Available The study was designed to evaluate the effects of solids in suspension in seawater on clams (Chamelea gallina. The aim was to investigate the possible correlation between the widespread deaths of clams in the coastal waters of the central and northern Adriatic in the last five years and increased concentrations of solids in suspension. The research involved conducting 96-hour tests on clams farmed in aquariums containing filtered seawater. The tests were preceded by a 7-day adaptation stage to allow the molluscs to acclimatise. During this period, the clams were fed on unicellular seaweed (Dunaliella tertiolecta. The molluscs were exposed to particles of solids in suspension consisting of pools of silica gel (SiO2 granules of various sizes, similar to those constituting silt, whose presence and suspension in the sea considerably increase after heavy rain and heavy seas. The study established that the number of deaths caused by solids suspended in seawater at the concentrations used in the tests was not statistically significant.

  15. Bivalves as indicators of environmental variation and potential anthropogenic impacts in the southern Barents Sea

    OpenAIRE

    Carroll, Michael L.; Johnson, Beverly J.; Henkes, Gregory A.; McMahon, Kelton W.; Voronkov, Andrey; Ambrose, William G.; Denisenko, Stanislav G.

    2009-01-01

    Identifying patterns and drivers of natural variability in populations is necessary to gauge potential effects of climatic change and the expected increases in commercial activities in the Arctic on communities and ecosystems. We analyzed growth rates and shell geochemistry of the circumpolar Greenland smooth cockle, Serripes groenlandicus, from the southern Barents Sea over almost 70 years between 1882 and 1968. The datasets were calibrated via annually-deposited growth lines, and growth, st...

  16. Bivalve tissue as a carbon and nitrogen isotope baseline indicator in coastal ecosystems

    Science.gov (United States)

    Fukumori, Kayoko; Oi, Misa; Doi, Hideyuki; Takahashi, Daisuke; Okuda, Noboru; Miller, Todd W.; Kuwae, Michinobu; Miyasaka, Hitoshi; Genkai-Kato, Motomi; Koizumi, Yoshitsugu; Omori, Koji; Takeoka, Hidetaka

    2008-08-01

    Pinctada fucata martensii mantle tissue and gut contents were examined as baseline indicators of carbon and nitrogen isotope composition at six stations in the Uwa Sea, Japan. Substantial variations in δ13C and δ15N values of oysters among stations were observed, with δ13C being consistently lower at Hiburi Island (-18.1‰) than at other stations (-17.2‰). Oysters from fish farm sites were enriched in δ15N (8.1‰) relative to those from unaffected sites (6.8‰), suggesting that fish farming tends to increase baseline δ15N values. The mean Δ δ13C (0.8‰) was consistent over space and time, whereas the average Δ δ15N slightly increased in summer. The relatively low δ15N enrichment compared to the theoretical isotope fractionation factor (3.4‰) may be due to oyster-specific physiological attributes. Carbon and nitrogen isotope turnover rates were roughly similar within a tissue, and mantle tissue turnover rate was estimated to be 120-180 days. These results indicated that oysters are long-term integrators of δ13C and δ15N from their diet and that δ13C of oysters is a more accurate bioindicator of isotopic baselines than δ15N for marine ecological studies.

  17. Study on impact of dinoflagellate Alexandrium tamarense on life activities of marine bivalves

    Institute of Scientific and Technical Information of China (English)

    Yan Tian(颜天); Zhou Mingjiang(周名江); Fu Meng(傅萌); Wang Liping

    2003-01-01

    The effects of a PSP producing dinoflagellate Ale xandrium tamarense on marine bivalvesat their several important life stages: egg, D- shape larva, eyespot larva, juvenile and adult, were stud-ied. The results show that the hatching, survival, activity, filtration and growth were adversely affectedby the alga and the impact was significantly increased with the increase of algal density. The inhibitoryeffect on egg hatching was most significant, which the hatching rate was only 30% of the control whenexposed to the alga at 100 cell/cm3 after 36 h. Further experiments show that the algal culture, re-sus-pended cells and cell fragments had the inhibitory effect, while no such effect was from the cell-freemedium, cell contents and standard STX. The results indicate that the alga could produce unknown tox-ins, rather than PSP, associated with the cell surface.

  18. Nucleosomal organization of chromatin in sperm nuclei of the bivalve mollusc Aulacomya ater.

    Science.gov (United States)

    Olivares, C; Ruiz, S

    1991-03-13

    The sperm nuclei of Aulacomya ater, family Mitylidae, contain three proteins (X, Aa5 and Aa6) which are specific to this cell type coexisting with a set of five somatic-type histones. Information about the chromatin structure resulting from this kind of association is scarce. Therefore, we have probed the structure of this sperm chromatin through digestion with micrococcal nuclease in combination with salt fractionation. The data obtained have allowed us to propose a nucleosomal arrangement for this chromatin. However, two types of nucleosomes would be present in agreement with their protein components. PMID:1861676

  19. Etude succincte d'échantillons de bivalves et de phytoplancton

    OpenAIRE

    Lassus, Patrick; Le Baut, Claire; Mondeguer, Florence; Bohec, Madeleine

    1993-01-01

    A la suite du stage réalisé par Geneviève Arzul dans différents laboratoires chiliens travaillant sur les microalgues toxiques, des échantillons provenant de Cochamo (estuaire de Relonarvi) ont été étudiés par le Laboratoire DEUPN de Nantes. Il s'agissait de prélèvements phytoplanctoniques riches en Dinophysis et fixés au formol, ainsi que de glandes digestives d'Aulacomya ater conservées dans 100 ml d'acétone.

  20. Cryptosporidium in Bivalves as Indicators of Fecal Pollution in the California Coastal Ecosystem

    OpenAIRE

    Miller, Woutrina

    2004-01-01

    information expected to be derived frorn the research.) The California coastal ecosystem is highly impacted by fecal pollution from sewage outfalls, agricultural runoff, and urban stormwater runoff. In the past, water quality monitoring has focused on toxins and bacterial coliform counts. However, this methodology does not address the public health threat of zoonotic protozoal parasites or allow for the identification of pollution sources. Cryptosporidium species are pathoge...

  1. 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...

  2. Clamming up: environmental forces diminish the perceptive ability of bivalve prey.

    Science.gov (United States)

    Smee, Delbert L; Weissburg, Marc J

    2006-06-01

    The lethal and nonlethal impacts of predators in marine systems are often mediated via reciprocal detection of waterborne chemical signals between consumers and prey. Local flow environments can enhance or impair the chemoreception ability of consumers, but the effect of hydrodynamics on detection of predation risk by prey has not been investigated. Using clams as our model organism, we investigated two specific questions: (1) Can clams decrease their mortality by responding to predators? (2) Do fluid forces affect the ability of clams to detect approaching predators? Previous research has documented a decrease in clam feeding (pumping) in response to a neighboring predator. We determined the benefits of this behavior to survivorship by placing clams in the field with knobbed whelk or blue crab predators caged nearby and compared mortality between these clams and clams near a cage-only control. Significantly more clams survived in areas containing a caged predator, suggesting that predator-induced alterations in feeding reduce clam mortality in the field. We ascertained the effect of fluid forces on clam perception of predators in a laboratory flume by comparing the feeding (pumping) behavior of clams in response to crabs and whelks in flows of 3 and 11 cm/s. Clams pumped significantly less in the presence of predators, but their reaction to blue crabs diminished in the higher velocity flow, while their response to whelks remained constant in both flows. Thus, clam reactive distance to blue crabs was affected by fluid forces, but hydrodynamic effects on clam perceptive distance was predator specific. After predators were removed, clams exposed to whelks took significantly longer to resume feeding than those exposed to blue crabs. Our results suggest that prey perception of predators can be altered by physical forces. Prey detection of predators is the underlying mechanism for trait-mediated indirect interactions (TMIIs), and recent research has documented the importance of TMIIs to community structure. Since physical forces can influence prey perception, the prevalence of TMIIs in communities may, in part, be related to the sensory ability of prey, physical forces in the environment that impact sensory performance, and the type of predator detected. PMID:16869434

  3. Significant genetic differentiation among populations of Anomalocardia brasiliana (Gmelin, 1791: a bivalve with planktonic larval dispersion

    Directory of Open Access Journals (Sweden)

    Cinthya Cristina Bulhões Arruda

    2009-01-01

    Full Text Available 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.

  4. 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.

  5. The bivalve Laternula elliptica: physiological and molecular response to changing coastal Antarctic environments

    OpenAIRE

    Husmann, Gunnar

    2013-01-01

    Increasing temperatures and glacier-disintegration at the Western Antarctic Peninsula (WAP) are presently altering environmental conditions in shallow coastal areas. Rising water temperatures, enhanced ice scouring impacts as well as increasing input of inorganic sediments from melt water runoff are anticipated to particularly affect slow growing sessile benthic filter feeders like the Antarctic soft shell clam Laternula elliptica, a long-lived species which is a major component of the nearsh...

  6. Integrated assessment of ceria nanoparticle impacts on the freshwater bivalve Dreissena polymorpha.

    Science.gov (United States)

    Garaud, Maël; Auffan, Mélanie; Devin, Simon; Felten, Vincent; Pagnout, Christophe; Pain-Devin, Sandrine; Proux, Olivier; Rodius, François; Sohm, Bénédicte; Giamberini, Laure

    2016-09-01

    Exposures in realistic environmental conditions are essential to properly assess the effects of emerging pollutants on ecosystems. While ceria nanoparticles (nCeO2) production and use are expanding quickly, ecotoxicity studies remain very scarce. In this study, we set up experimental systems reproducing a simplified ecosystem to assess the effects of a chronic exposure to citrate-coated nCeO2 (ci-CeO2) and bare nCeO2 (ba-CeO2) on the freshwater mussel Dreissena polymorpha using an integrated multibiomarker approach. The fate of nanoparticles was tightly monitored to properly characterize the exposure. Organisms were exposed for 3 weeks and sampled weekly for biomarker analysis. Mussel filter-feeding activity resulted in significant removal of nCeO2 from the water column. At the same time, bioaccumulation was low, reaching its maximum in the first week. Mussels bioaccumulated ci-CeO2 three times more than ba-CeO2, probably due to coating-related differences in their behavior in the water column and in organisms. Meanwhile, biomarker results were integrated and synthesized using linear discriminant analysis, highlighting that pi-glutathione-S-transferase (piGST) mRNA, catalase (CAT) activity and lysosomal system were the most impacted of the seven biomarkers singled out by the discriminant analysis. These biomarker responses indicated that mussels exposed to both forms of nCeO2 were stressed and differentiate from the controls. Moreover, they responded differently to ba-CeO2 and ci-CeO2 exposure. However, biomarkers used in the experimental conditions of this study did not indicate severe nCeO2 toxicity on mussels, as cellular damage biomarkers and mussel filtering activity were left unimpaired. However, further studies are needed to investigate if the slight perturbations observed could lead to populational impacts in the long term. PMID:26830045

  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. Experimental contamination of margaritana margaritifera (L) (a Fresh water bivalve) by caesium 137; Contamination experimentale de margaritana margaritifera (L) (bivalve d'eau douce) par le cesium 137

    Energy Technology Data Exchange (ETDEWEB)

    Foulquier, L.; Bovard, P.; Grauby, A. [Commissariat a l' Energie Atomique, Cadarache (France). Centre d' Etudes Nucleaires

    1966-07-01

    The hydro biological research carried out in the Radio-Ecology Section has led the authors to study some Margaritana sampling stations situated down-stream from the Monts d'Arree nuclear power station. They describe the preservation and contamination methods used for fixing the {sup 137}Cs concentration factors in the case of Margaritana Margaritifera (L). The results of experiments carried out over a period of one hundred days show that the specific activity of the various organs is stabilized after thirty to thirty-five days. The authors have noticed a relatively low adsorption on the shell through the intermediary of micro-organisms, and a strong and rapid absorption in the soft parts. The concentration factors have values, at equilibrium, of around: 9 for the shell, 300 for all the organs, and 38 for the whole animal. A comparison of these results with work published by other authors makes it possible to draw general conclusions concerning the mechanism of {sup 137}Cs fixation by lamellibranch, as well as their capacity of fixation. (author) [French] Les etudes hydrobiologiques effectuees au sein de la Section de Radio-Ecologie ont amene les auteurs a etudier des stations de prelevement de Margaritana en aval de la Centrale Nucleaire des Monts d'Arree. Ils decrivent les methodes de conservation et de contamination utilisees pour l'etablissement des facteurs de concentration du {sup 137}Cs par Margaritana margaritifera (L). Les resultats des experimentations menees pendant cent jours montrent que les activites specifiques de la coquille et des differents organes se stabilisent au bout de trente a trente-cinq jours. Les auteurs constatent une adsorption relativement faible sur la coquille par l'intermediaire des micro-organismes et une absorption forte et rapide dans les parties molles. Les facteurs de concentration se situent, a l'equilibre, autour de: 9 pour la coquille, 300 pour l'ensemble des organes et 38 si l'on considere l'animal total. Cette etude comparee a celles deja effectuees par d'autres auteurs permet de degager des idees generales sur le mode et la capacite de fixation du {sup 137}Cs par les lamellibranches. (auteur)

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

    DEFF Research Database (Denmark)

    Larsen, Poul Scheel; Riisgård, Hans Ulrik

    2012-01-01

    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...... measurements depends on the percent reduction in particle concentration (1006P) 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...

  10. Live algae as a vector candidate for hydrophobic polychlorinated biphenyls translocation to bivalve filter feeders for laboratory toxicity test.

    Science.gov (United States)

    Jo, Qtae; Kim, Su-Kyoung; Lee, Chae Sung; Lee, Pil Yong

    2011-11-01

    Live algae carrying hydrophobic xenobiotics can be an effective vector candidate for the chemical translocation to filter feeders in the laboratory toxicity test, but information on their application is lacking. Time-course uptake and elimination of polychlorinated biphenyls (PCBs) (0, 50, 100, and 500 ng g(-1) by two key algal foods, Isochrysis galbana and Tetraselmis suecica, were measured. Both of the algae achieved maximum concentration in an hourafter PCBs exposure regardless the chemical concentrations in our time-course measurements (0, 1, 5, 10, 24, 48 and 72 hrs). Once achieved the maximum concentration, the algae shortly exhibited elimination or eliminating tendency depending on the chemical concentrations. Algae exposed to the chemical for 1 and 24 hrs (hereafter 1 and 24 hr vectors, respectively) were then evaluated as a chemical translocation vector by feeding test to larval and spat Crassostrea gigas. In the feeding test the 24 hr vector, which contained lower chemicals than the 1-hr vector, appeared to be more damaging the early lives of the oyster. This was particularly significant for vectors of higher PCBs (p<0.05), probably due to algal reduction in food value by the prolonged chemical stress. These findings imply that 1 hr exposure is long enough for a generation of algal vector for laboratory toxicity test, minimizing data error resulted from reduction in food value by longer chemical stress.

  11. Reproductive periods of Lucina pectinata (BIVALVE; LUCINIDAE) in the Paranaguá Estuarine Complex, Paraná - Brazil.

    Science.gov (United States)

    Christo, S W; Ivachuk, C S; Ferreira-Júnior, A L; Absher, T M

    2016-06-01

    The objectives of the present study is to describe the size for exploitation and gonadal maturation of L. pectinata in Peças Island in Paraná coast. Twenty two individuals were sampled every month, from an intertidal flat of the Peças River, Municipality of Guaraqueçaba, during two periods - summer/autumn and winter of the 2009. Environmental parameter data was obtained at the same time of the biological sampling: temperature, salinity and seawater transparency at the Peças River mouth. The animals' height, length, width, gross weight, wet weight of meat and dry weight of meat were measured at the lab. The gonad development stages (GDS), condition index (CI) and yield index (Y) were calculated. Sex identification was conducted by direct observation of the gonads and gametes under an optic microscope. Individuals were classified as males (M), females (F) or undetermined (U). The medium height observed was of 49.62 ± 6.84 mm. Period of more expressive gonad repletion were observed in summer when water temperature was higher. Results of GDS in both periods showed a predominance of partially filled gonad stages. This may be related with the fact that L. pectinata has intense gametogenesis activity, that is, the organisms do not have a resting interval, but go back to gonad restructuring rapidly after releasing the gametes. The continuity of the reproductive cycle of the specimens found in both studied periods could demonstrate a possible continuous reproduction of the species and a size for exploitation above 40.00 mm of height. PMID:26934151

  12. Bottom-up and top-down forces in a tropical intertidal ecosystem : The interplay between seagrasses, bivalves and birds

    NARCIS (Netherlands)

    de Fouw, Jimmy

    2016-01-01

    Zeegrassen zijn zogenaamde ‘biobouwers’ en zijn de basis voor veel kustecosystemen. Het Waddengebied Banc d’Arguin is zo’n kustgebied. Het zeegras Zostera noltii hier barst van het leven waar o.a. de kanoet (Calidris canutus canutus) van leeft. Zeegrassen hebben een belangrijke sturende rol als fund

  13. Anoxic or aerial survival of bivalves and other euryoxic invertebrates as a useful response to environmental stress - A comprehensive review

    NARCIS (Netherlands)

    De Zwaan, A.; Eertman, R.H.M.

    1996-01-01

    Laboratory and field studies have demonstrated the applicability of anoxic/aerial survival as an early warning indicator of contaminant induced stress. The effects of xenobiotics, including heavy metals, organometals and organics as well as contaminated field sediments have been investigated. The us

  14. Mortality of unionid bivalves (Mollusca) associated with Dreissenid mussels (Dreissena polymorpha and D. bugensis) in Presque Isle Bay, Lake Erie

    Science.gov (United States)

    Schloesser, Don W.; Masteller, Edwin C.

    1999-01-01

    Two exotic species of dreissenid mussels (Dreissena polymorpha and D. bugensis) began to colonize bottom substrates in Presque Isle Bay, Lake Erie in 1990. By 1991, all native unionid (Unionidae) shells were infested by dreissenids. In 1990 and 1991, about 500 individual unionids of 15 species were collected: in 1992, 246 individuals of 12 species were collected; in 1993, 64 individuals of 6 species; in 1994, three individuals of three species; and in 1995, no unionids were found. In general, infestation indices of unionids were relatively low in 1990 and 1991, increased in 1992, and decreased in 1993. Mortality of unionids associated with infestation in the bay occurred in a shorter period of time (ca. two to three years) than has been documented in other water bodies. Observations in an area of Presque Isle not included in the present study, indicate that a small remnant population of unionids exists in the presence of heavily-colonized substrates by dreissenid mussels. Since other shallow-water areas of Lake Erie support infestation-free unionids in the presence of dreissenid mussels, it is hoped that some unionids will survive in Presque Isle Bay of Lake Erie.

  15. Review of the RNA Interference Pathway in Molluscs Including Some Possibilities for Use in Bivalves in Aquaculture

    Directory of Open Access Journals (Sweden)

    Leigh Owens

    2015-03-01

    Full Text Available Generalised reviews of RNA interference (RNAi in invertebrates, and for use in aquaculture, have taken for granted that RNAi pathways operate in molluscs, but inspection of such reviews show little specific evidence of such activity in molluscs. This review was to understand what specific research had been conducted on RNAi in molluscs, particularly with regard to aquaculture. There were questions of whether RNAi in molluscs functions similarly to the paradigm established for most eukaryotes or, alternatively, was it more similar to the ecdozoa and how RNAi may relate to disease control in aquaculture? RNAi in molluscs appears to have been only investigated in about 14 species, mostly as a gene silencing phenomenon. We can infer that microRNAs including let-7 are functional in molluscs. The genes/proteins involved in the actual RNAi pathways have only been rudimentarily investigated, so how homologous the genes and proteins are to other metazoa is unknown. Furthermore, how many different genes for each activity in the RNAi pathway are also unknown? The cephalopods have been greatly overlooked with only a single RNAi gene-silencing study found. The long dsRNA-linked interferon pathways seem to be present in molluscs, unlike some other invertebrates and could be used to reduce disease states in aquaculture. In particular, interferon regulatory factor genes have been found in molluscs of aquacultural importance such as Crassostrea, Mytilus, Pinctada and Haliotis. Two possible aquaculture scenarios are discussed, zoonotic norovirus and ostreid herpesvirus 1 to illustrate the possibilities. The entire field of RNAi in molluscs looks ripe for scientific exploitation and practical application.

  16. Simulated leakage of high pCO2 water negatively impacts bivalve dominated infaunal communities from the Western Baltic Sea.

    Science.gov (United States)

    Schade, Hanna; Mevenkamp, Lisa; Guilini, Katja; Meyer, Stefanie; Gorb, Stanislav N; Abele, Doris; Vanreusel, Ann; Melzner, Frank

    2016-01-01

    Carbon capture and storage is promoted as a mitigation method counteracting the increase of atmospheric CO2 levels. However, at this stage, environmental consequences of potential CO2 leakage from sub-seabed storage sites are still largely unknown. In a 3-month-long mesocosm experiment, this study assessed the impact of elevated pCO2 levels (1,500 to 24,400 μatm) on Cerastoderma edule dominated benthic communities from the Baltic Sea. Mortality of C. edule was significantly increased in the highest treatment (24,400 μatm) and exceeded 50%. Furthermore, mortality of small size classes (0-1 cm) was significantly increased in treatment levels ≥6,600 μatm. First signs of external shell dissolution became visible at ≥1,500 μatm, holes were observed at >6,600 μatm. C. edule body condition decreased significantly at all treatment levels (1,500-24,400 μatm). Dominant meiofauna taxa remained unaffected in abundance. Densities of calcifying meiofauna taxa (i.e. Gastropoda and Ostracoda) decreased in high CO2 treatments (>6,600 μatm), while the non - calcifying Gastrotricha significantly increased in abundance at 24,400 μatm. In addition, microbial community composition was altered at the highest pCO2 level. We conclude that strong CO2 leakage can alter benthic infauna community composition at multiple trophic levels, likely due to high mortality of the dominant macrofauna species C. edule. PMID:27538361

  17. Effects of the dinoflagellate Karenia brevis on larval development in three species of bivalve mollusc from Florida.

    Science.gov (United States)

    Leverone, Jay R; Blake, Norman J; Pierce, Richard H; Shumway, Sandra E

    2006-07-01

    The effects of Karenia brevis (Wilson clone) on larval survival and development of the northern quahog, Mercenaria mercenaria, eastern oyster, Crassostrea virginica and bay scallop, Argopecten irradians, were studied in the laboratory. Larvae were exposed to cultures of whole and lysed cells, with mean total brevetoxin concentrations of 53.8 and 68.9 microgL(-1), respectively. Survival of early (3-day-old) larvae was generally over 85% for all shellfish species at K. brevis densities of 100 cells ml(-1) or less, and not significantly different between whole and lysed culture. At 1000 cells ml(-1), survival was significantly less in lysed culture than whole culture for both M. mercenaria and C. virginica. Survival of late (7-day-old) larvae in all three species was not significantly affected by K. brevis densities of 1000 cells ml(-1) or less. At 5000 cells ml(-1), however, survival was reduced to 37%, 26% and 19% for A. irradians, M. mercenaria and C. virginica, respectively. Development of C. virginica and M. mercenaria larvae was protracted at K. brevis densities of 1000 cells ml(-1). These results suggest that blooms of K. brevis, and particularly their associated brevetoxins, may have detrimental consequences for Florida's shellfisheries by disrupting critical larval processes. Special attention should be paid to blooms of K. brevis where these shellfish occur naturally or where aquaculture and restoration activities are either ongoing or planned.

  18. Polychlorinated biphenyls, organochlorine pesticides and polycyclic aromatic hydrocarbons in a one-off global survey of bivalves

    DEFF Research Database (Denmark)

    Vorkamp, Katrin; Strand, Jakob; Christensen, Jan H.;

    2010-01-01

    differences of up to three orders of magnitude were observed, with the highest concentrations at Boston harbour (Sigma PCB 338 ng g(-1) dw, Sigma PAH 5966 ng g(-1) dw) and the Sydney estuary (Sigma PCB 282 ng g(-1) dw, Sigma PAH 1453 ng g(-1) dw). Local impacts were also found for the Greenland capital Nuuk...

  19. Population dynamics of the venerid bivalve, Tawera gayi (Hupé, 1854) in the Ushuaia Bay, Beagle Channel

    OpenAIRE

    Lomovasky, B.; Brey, Thomas; Morriconi, E.

    2005-01-01

    Growth, productivity and potential for exploitation of the clam Tawera gayi from shallow waters (3 to 5 m) of Ushuaia Bay, Beagle Channel were investigated. Mean abundance and biomass in the study area were 1091 ± 737 ind m^-2 and 901.83 g SFWM m^-2 (shell free wet mass) respectively. Individual growth was described best by the von Bertalanffy growth model with the parameter values H? = 28.03 mm, K = 0.288 y^1, t0 = -0.34 (r^2 = 0.83). Annual production of the population was estimated to be 1...

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

    International Nuclear Information System (INIS)

    Since rehabilitation of the Rum Jungle copper-uranium mine 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 of these metals in the surface waters of the East Branch. Using matching shell valves, the SIMS metal signals (i.e. counts) in the shells were converted into concentrations using inductively coupled plasma mass spectrometry. The average concentrations for Cu, Mn, Zn, Ni and Co in the shells of V. angasi decreased (3-13 fold) with increasing distance downstream of the mine site, until concentrations characteristic of the non-exposed sites were reached (i.e. 30 km downstream). 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. This trend was not evident for Pb and Fe, with concentrations in the shell remaining similar to those of the reference sites. Highly significant (P 0.05) linear relationships were found between the total concentrations of metals in the shells and those in the sediments. However, when sediment metal concentrations were normalised to Fe, significant (P = 0.05) linear relationships were found for Cu, Zn and Ni. Overall, the 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 system over their lifetime