Histopathologic and biochemical responses in Arctic marine bivalve molluscs exposed to experimentally spilled oil

Energy Technology Data Exchange (ETDEWEB)

Neff, J.M.; Hillman, R.E.; Carr, R.S.; Buhl, R.L.; Lahey, J.I.

1987-01-01

Following two experimental spills of chemically dispersed and undispersed crude oil in shallow bays on the northwest coast of Baffin Island bivalve molluscs accumulated significant amounts of petroleum hydrocarbons in bay receiving dispersed oil and in those receiving crude oil alone. Specimens of Mya truncata and Macoma calcarea for histopathologic examination were collected immediately before, immediately after and one year after the experimental oil spills. Immediately after there was increased gill and digestive tract necrosis in Mya from the chemically dispersed oil. After one year a few clams had granulocytomas throughout the tissues. Three clams receiving oil alone collected one year after the spill had invasive neoplasias. There were few lesions in Macoma immediatelly after or one year after the spill; animals had a high incidence of vacuolization of the digestive tubule epithelium. The incidence of parasitism and hemocytic infiltration also was higher in Maccoma. Clams Mya truncata were collected for biochemical analysis before, after and two weeks after the simulated oil spills. Concentations in the clam tissues of glucose, glycogen, trehalose, total lipid, and free amino acids were measured; free amino acids in adductor muscles were the most useful indices of pollutant stress. The results of the biochemical analyses indicate that Mya were not severely stressed by either dispersed oil or oil alone. After two weeks, clams from the dispersed oil bays were nearly normal, while those from the bay receiving oil alone appeared stressed. These results seem to corroborate results that the acute effects of dispersed oil are greater than those of undispersed oil, but effects of undispersed oil on infaunal molluscs develop more slowly and persist longer than those from dispersed oil. 43 refs., 2 figs., 6 tabs.

Travel report Mauritania bivalve Molluscs october 2008

NARCIS (Netherlands)

Poelman, M.

2008-01-01

During the last four years Mauritania has been working on the completion of a Food Safety Program of Bivalve Mollusks, in order to obtain an export approval by the Europe Union. During the preparations for an inspection by the FVO (Food and Veterinary Office) no fisheries or production activities

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

Energy Technology Data Exchange (ETDEWEB)

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

2008-02-15

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

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Microflora in the Soft Tissue of the Pacific Oyster Crassostrea gigas Exposed to the Harmful Microalga Heterosigma akashiwo.

Science.gov (United States)

Takenaka, Shinkuro; Yoshikawa, Takeshi; Kadowaki, Shusaku; Okunishi, Suguru; Maeda, Hiroto

2017-01-01

　A marine raphidophyte Heterosigma akashiwo is a causative agent of harmful microalgal blooms, which often cause the massive mortality of aquacultured finfish. In the present study, the Pacific oyster Crassostrea gigas was reared with H. akashiwo, and effect of the microalga on filter-feeding behavior and microflora of the gastrointestinal tract was investigated. The intake of the raphidophyte cells inhibited the molluscan filter-feeding activities, suggesting the negative physiological effect of the microalgal cell contents. However, the bivalves ingested the H. akashiwo cells to the same extent as the diatom Chaetoceros calcitrans, a non-harmful indicator to estimate the filtration rate, showing a continuation of their non-selective ingestion of the phytoplankton. Microflora of the oyster soft tissue was dominated by bacteria affiliated with the family Rhodobacteraceae, some of which are associated with microalgae. In addition, the Bacteroidetes species, in which algicidal bacteria are included, were also found in the bivalve individuals exposed to H. akashiwo. These results suggested that the ingested phytoplankton affected the microbial flora in the gastrointestinal tracts, some constituents of which helped the mollusc assimilate the ingested red tide phytoplankton. This study will provide beneficial information to clarify mechanisms by which the oyster evades the ichthyotoxicity of harmful microalgae and the participation of the intestinal microorganisms in these processes.

SEASONAL VARIATION IN LYSOSOMAL DESTABILIZATION IN OYSTERS, CRASSOSTREA VIRGINICA. (R826201)

Science.gov (United States)

Lysosomal destabilization assays have been used as valuable biomarkers of pollutant exposures in a variety of bivalve and fish species. The responses of oysters, Crassostrea virginica, deployed at and native to various reference and degraded sites were evaluated for lys...

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.

Bivalves such as, Crassostrea spp., Meretrix casta, Placuna placenta and Polymesoda erosa are largely consumed as edible seafood. It forms natural source of nutrition in coastal and worldwide population. Free radical scavenging activities...

Patterns of DNA barcode variation in Canadian marine molluscs.

Science.gov (United States)

Layton, Kara K S; Martel, André L; Hebert, Paul D N

2014-01-01

Molluscs are the most diverse marine phylum and this high diversity has resulted in considerable taxonomic problems. Because the number of species in Canadian oceans remains uncertain, there is a need to incorporate molecular methods into species identifications. A 648 base pair segment of the cytochrome c oxidase subunit I gene has proven useful for the identification and discovery of species in many animal lineages. While the utility of DNA barcoding in molluscs has been demonstrated in other studies, this is the first effort to construct a DNA barcode registry for marine molluscs across such a large geographic area. This study examines patterns of DNA barcode variation in 227 species of Canadian marine molluscs. Intraspecific sequence divergences ranged from 0-26.4% and a barcode gap existed for most taxa. Eleven cases of relatively deep (>2%) intraspecific divergence were detected, suggesting the possible presence of overlooked species. Structural variation was detected in COI with indels found in 37 species, mostly bivalves. Some indels were present in divergent lineages, primarily in the region of the first external loop, suggesting certain areas are hotspots for change. Lastly, mean GC content varied substantially among orders (24.5%-46.5%), and showed a significant positive correlation with nearest neighbour distances. DNA barcoding is an effective tool for the identification of Canadian marine molluscs and for revealing possible cases of overlooked species. Some species with deep intraspecific divergence showed a biogeographic partition between lineages on the Atlantic, Arctic and Pacific coasts, suggesting the role of Pleistocene glaciations in the subdivision of their populations. Indels were prevalent in the barcode region of the COI gene in bivalves and gastropods. This study highlights the efficacy of DNA barcoding for providing insights into sequence variation across a broad taxonomic group on a large geographic scale.

In vivo effects of metaldehyde on Pacific oyster, Crassostrea gigas: comparing hemocyte parameters in two oyster families.

Science.gov (United States)

Moreau, Pierrick; Burgeot, Thierry; Renault, Tristan

2015-06-01

Pollutants via run-off into the ocean represent a potential threat to marine organisms, especially bivalves such as oysters living in coastal environments. These organisms filter large volumes of seawater and may accumulate contaminants within their tissues. Pesticide contamination in water could have a direct or indirect toxic action on tissues or cells and could induce alteration of immune system. Bivalve immunity is mainly supported by hemocytes and participates directly by phagocytosis to eliminate pathogens. Some studies have shown that pesticides can reduce immune defences and/or modify genomes in vertebrates and invertebrates. Metaldehyde is used to kill slugs, snails and other terrestrial gastropods. Although metaldehyde has been detected in surface waters, its effects on marine bivalves including the Pacific oyster, Crassostrea gigas, have never been studied. Given the mode of action of this molecule and its targets (molluscs), it could be potentially more toxic to oysters than other pesticides (herbicides, fungicides, insecticides, etc.). Effects of metaldehyde on oyster hemocyte parameters were thus monitored through in vivo experiments based on a short-term exposure. In this work, metaldehyde at 0.1 μg/L, which corresponds to an average concentration detected in the environment, modulated hemocyte activities of Pacific oysters after an in vivo short-term contact. Individuals belonging to two families showed different behaviours for some hemocyte activities after contamination by metaldehyde. These results suggested that effects of pollutants on oysters may differ from an individual to another in relation to genetic diversity. Finally, it appears essential to take an interest in the effects of metaldehyde on a wide variety of aquatic invertebrates including those that have a significant economic impact.

Modulation of pumping rate by two species of marine bivalve molluscs in response to neurotransmitters: Comparison of in vitro and in vivo results.

Science.gov (United States)

Frank, Dana M; Deaton, Lewis; Shumway, Sandra E; Holohan, Bridget A; Ward, J Evan

2015-07-01

Most studies regarding the neuroanatomy and neurophysiology of molluscan ctenidia have focused on isolated ctenidial tissue preparations. This study investigated how bivalve molluscs modulate their feeding rates by examining the effects of a variety of neurotransmitters, including serotonin, dopamine, and the dopamine agonist apomorphine on both isolated ctenidial tissue and in intact members of two commercially important bivalve species: the blue mussel, Mytilus edulis; and the bay scallop Argopecten irradians. In particular, we examined the effect of changes in: 1) beat of the lateral cilia (in vitro), 2) distance between ctenidial filaments and/or plicae (in vivo), and 3) diameter of the siphonal openings (in vivo) on alteration of bulk water flow through the mantle cavity. Important differences were found between isolated tissue and whole animals, and between species. Drugs that stimulated ciliary beat in vitro did not increase water processing rate in vivo. None of the treatments increased water flow through the mantle cavity of intact animals. Results suggest that A. irradians was primarily modulating lateral ciliary activity, while M. edulis appeared to have a number of ways to control water processing activity, signifying that the two species may have different compensatory and regulatory mechanisms controlling feeding activity. Copyright © 2015 Elsevier Inc. All rights reserved.

GREATER HEMOCYTE BACTERICIDAL ACTIVITY IN OYSTERS (CRASSOSTREA VIRGINICA) FROM A RELATIVELY CONTAMINATED SITE IN PENSACOLA BAY, FLORIDA.

Science.gov (United States)

Bivalve mollusks such as Crassostrea virginica inhabiting polluted estuaries and coastal areas may bioaccumulate high concentrations of contaminants without apparent ill effects. However, changes in putative internal defense activities have been associated with contaminant accumu...

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

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Tiziana Tedde

2013-06-01

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

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

International Nuclear Information System (INIS)

Ivanina, Anna V.; Sokolova, Inna M.

2013-01-01

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

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

Indian marine bivalves: Potential source of antiviral drugs

Digital Repository Service at National Institute of Oceanography (India)

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

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

Assessment of bioavailability of weathered oil residues using caged bivalves (Crassostrea gigas and Mytilus edulis) as indicator organisms

International Nuclear Information System (INIS)

Bleczinski, C.F.; Costa, H.J.; Rigatti, M.J.; Wong, M.C.; Boehm, P.D.

1993-01-01

In April 1988, an estimated 400,000 gallons of San Joaquin Valley crude oil spilled into Peyton Slough and subsequently into Suisun Bay from an oil refinery in Martinez, California. The crude oil initially impacted a number of ecologically sensitive environments including estuarine water, marsh grasses, marsh and shoreline sediment, and intertidal sediment. A four-year oil weathering study was performed to determine the concentrations of environmentally important compounds in the stranded oil, to monitor changes in these concentrations over time, and to assess the potential long-term impact of the spilled oil in these various environments. As a result of marked differences in the rate of weathering at the different sites, a bioaccumulation component was added to the original study design in order to assess the bioavailability of crude oil residues remaining four-years post spill. Caged bivalves (Crassostrea gigas and Mytilus edulis) were deployed at the three study sites as sentinel organisms and exposed for three months. Sediments and organism tissues were analyzed using gas chromatography/mass spectrometry for polynuclear aromatic hydrocarbon (PAH) assemblages characteristics of the spilled oil. Advanced hydrocarbon fingerprinting techniques (e.g., double ratio plots of characteristic alkyl PAHs) were used to match distributions in the organisms and in the study site sediments

Uptake and metabolism of 14C-chloropyrifos by marine bivalves

International Nuclear Information System (INIS)

Zhong, C.G.; Chen, S.; Zhao, X.; Shi, J.; Carvalho, F.P.

1999-01-01

The uptake and metabolism of 14 C-chlorpyrifos by two marine bivalves, Paphia undulata and Sinonovacula constricta, were studied in a simulated ecosystem. The experiments were carried out in two 30 L glass tanks containing each 20 L of filtered sea water, contaminated with 14 C-chlorpyrifos 1.85x10 4 Bq.L -1 (16.7 μg.L -1 ) at the beginning of the exposure period. At different time intervals, three specimens of each species were sampled for analysis of the pesticide in the molluscs tissues. The 14 C-chlorpyrifos residues were extracted from the digestive gland of the molluscs and analyzed by co-chromatography with pesticide standards by TLC methods described before

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

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Kristian G. Jakobsen

2016-12-01

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

Bioaccumulation of 210Po in common gastropod and bivalve species from the northern Gulf.

Science.gov (United States)

Uddin, S; Bebhehani, M

2014-06-01

This study sets the baseline for the concentration of the natural-series radionuclide polonium-210 in two species of gastropods and four species of bivalves that are common to the Northern Arabian/Persian Gulf. (210)Po is primarily absorbed from water and via ingestion of detrital material by gastropoda and bivalves. This concentrated (210)Po can then be passed along to the next trophic level of the marine food web. The lowest (210)Po concentration was measured in the gastropod Stomatella auricular (10.36-12.39Bq kg(-1)dry) and the highest in the bivalve Marica marmorata (193.51-215.60Bq kg(-1)dry). The measured concentration factor for these molluscs in the northern Gulf varied between 4.8 and 115×10(3), values very similar to the IAEA recommended value for bivalves and gastropods of 2×10(4). Copyright © 2014 Elsevier Inc. All rights reserved.

Tributyltin accumulation and effects in marine molluscs from West Greenland

Energy Technology Data Exchange (ETDEWEB)

Strand, J.; Asmund, G

2003-05-01

Tributyltin is accumulated in marine molluscs living in Greenland, with the highest levels found in harbour areas. - The levels of the antifouling agent tributyltin (TBT) and its breakdown products in bivalves were investigated in 1999-2000 at six areas along the west coast of Greenland with focus on locations inside and outside harbours. In addition female gastropods were examined for the development of TBT-induced masculine characteristics in form of imposex or intersex. The highest TBT concentration, 254 ng g{sup -1} ww, was found in the bivalve Mytilus edulis sampled inside Nuuk harbour, but significant TBT concentrations were also present in bivalves from the other harbour areas. Only low levels of TBT were detected in bivalves sampled outside the harbours and in several of the samples the TBT level was below the detection limit. The examination of neogastropods like Buccinum revealed that imposex development occurred in all the harbours. In contrast, imposex was not found in any neogastropods sampled outside the harbour areas. However, the value of marine neogastropods as indicators of TBT contamination in West Greenland seems limited, because of large species diversity and the difficulties in sampling enough specimens at least with the current sampling strategy. No effects, which could be related to TBT contamination, were found in the most abundant tidal gastropod in West Greenland, Littorina saxatilis.

Tributyltin accumulation and effects in marine molluscs from West Greenland

International Nuclear Information System (INIS)

Strand, J.; Asmund, G.

2003-01-01

Tributyltin is accumulated in marine molluscs living in Greenland, with the highest levels found in harbour areas. - The levels of the antifouling agent tributyltin (TBT) and its breakdown products in bivalves were investigated in 1999-2000 at six areas along the west coast of Greenland with focus on locations inside and outside harbours. In addition female gastropods were examined for the development of TBT-induced masculine characteristics in form of imposex or intersex. The highest TBT concentration, 254 ng g -1 ww, was found in the bivalve Mytilus edulis sampled inside Nuuk harbour, but significant TBT concentrations were also present in bivalves from the other harbour areas. Only low levels of TBT were detected in bivalves sampled outside the harbours and in several of the samples the TBT level was below the detection limit. The examination of neogastropods like Buccinum revealed that imposex development occurred in all the harbours. In contrast, imposex was not found in any neogastropods sampled outside the harbour areas. However, the value of marine neogastropods as indicators of TBT contamination in West Greenland seems limited, because of large species diversity and the difficulties in sampling enough specimens at least with the current sampling strategy. No effects, which could be related to TBT contamination, were found in the most abundant tidal gastropod in West Greenland, Littorina saxatilis

Concentration parameters for radionuclides by marine molluscs

International Nuclear Information System (INIS)

Nakahara, Motokazu; Makamura, Ryoichi; Suzuki, Yuzuru; Matsuba, Mitsue

1994-01-01

Accumulation of radionuclides from seawater and from food by marine molluscs was observed in the laboratory experiments to get bioconcentration parameters for the nuclides. The radionuclides investigated were 57 Co, 95m Tc, 103 Ru, 137 Cs, 65 Zn and 54 Mn. Several species of molluscs containing pelecypods, gastropods and cephalopod were used for the experimental organisms. For the uptake experiment from seawater, the organisms were kept for more than seven days in radioactive seawater containing those radionuclides together. Then the organisms were transferred into nonradioactive seawater to observe the loss of the nuclides from the organisms. Biphasic loss curves were observed for all of the nuclides. Bioconcentration parameters, such as uptake rate, excretion rate, biological half-life and concentration factor at steady state were estimated from the uptake and excretion curves of the nuclides by the organisms by applying an exponential model. In the uptake experiments from radioactive food, the phytoplankton (Tetraselmis tetrathele), the brown algae (Eisenia bicyclis) and the viscera of abalone (Haliotis discus) were fed to bivalves, herbivorous gastropods and carnivorous molluscs, respectively. After single feeding of the labelled food with the nuclides, retention of the nuclides in whole body of the organisms was followed for several weeks or more. The organisms showed relatively high retention of the nuclides in whole body, except 137 Cs and 54 Mn. Retention of 137 Cs and 54 Mn in the organisms one day after feeding of radioactive food was lower than 25% of the radioactivity dosed. (author)

Molluscs production associated to lunar-tide cycle: a case study in Paraíba State under ethnoecology viewpoint

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Alves Rômulo RN

2006-06-01

Full Text Available Abstract Molluscs have been for a long time a very important food resource for humans. Therefore, oysters, clams, and mussels are highly required at seafood markets. Like any commercial food, it is necessary that molluscs present good quality standards, concerning some criteria such as amount of meat and appearance. In bivalves, condition index or fattening index is considered a satisfactory method for estimating the amount of meat related to the shell cavity. Molluscs gatherers of Paraíba State coast, northeastern Brazil, state that molluscan meat production increases during spring tide (designated by them as maré de lançamento in opposition to the meat decrease which happens during neap tide (maré de quebramento (they are designated technically in Portuguese as maré de sizígia and maré de quadratura, respectively. Weperformed a survey on the production of unha-de-velho or 'oldman'snail' (Tagelus plebeius caught by molluscs gatherers in the estuary of River Paraíba do Norte, by observing locally their work, applying questionnaires, searching for a possible scientific relation of that molluscs condition to the gatherers empirical statement. Thus, we estimatedthe molluscs condition index through the method of solids percentage determination. We studied their work and the molluscs condition index during a full lunar-tide cycle. Determinations were carried out between 2nd September and 20th October, 1998, through 20 catches performed to obtain condition index from 400 bivalves. We observed that several biotic and abiotic ecological factors, namely reproduction cycle, biochemical components variations, animal size, and even parasitism, may affect the animal condition index. Despite this aspect, our present results confirmed a high overlapping (80% of the condition index curve with lunar-tide cycle, in agreement with the gatherers statement. Although we recognize the need for formulating and testing other hypotheses, we consider a priori that

A checklist of malacofauna of the Vellar Estuarine Mangroves, India

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K. Kesavan

2009-07-01

Full Text Available A survey conducted to know the diversity of malacofauna in Vellar estuarine mangroves (southeast coast of India. In this study, 13 species of molluscs (10 species of gastropods - Melampus ceylonicus, Cerithidea cingulata, Cassidula nucleus, Pythia plicata, Neritina (Dostia violacea, Littorina scabra, Littorina melanostoma, Ellobium aurisjudae, C. obtusa T. telescopium and Assiminea nitida and 3 species of bivalves - Perna viridis, Crassostrea madrasensis and Modiolus metcalfei were recorded. M. pulchella, C. obtusa, L. scabra and N. violacea were found arboreal. T. telescopium, C. cingulata and E. aurisjudae were found crawling on the intertidal mud.

Concentration parameters for radionuclides by marine molluscs

Energy Technology Data Exchange (ETDEWEB)

Nakahara, Motokazu; Makamura, Ryoichi; Suzuki, Yuzuru; Matsuba, Mitsue [National Inst. of Radiological Sciences, Nakaminato, Ibaraki (Japan). Nakaminato Lab. Branch Office

1994-03-01

Accumulation of radionuclides from seawater and from food by marine molluscs was observed in the laboratory experiments to get bioconcentration parameters for the nuclides. The radionuclides investigated were {sup 57}Co, {sup 95m}Tc, {sup 103}Ru, {sup 137}Cs, {sup 65}Zn and {sup 54}Mn. Several species of molluscs containing pelecypods, gastropods and cephalopod were used for the experimental organisms. For the uptake experiment from seawater, the organisms were kept for more than seven days in radioactive seawater containing those radionuclides together. Then the organisms were transferred into nonradioactive seawater to observe the loss of the nuclides from the organisms. Biphasic loss curves were observed for all of the nuclides. Bioconcentration parameters, such as uptake rate, excretion rate, biological half-life and concentration factor at steady state were estimated from the uptake and excretion curves of the nuclides by the organisms by applying an exponential model. In the uptake experiments from radioactive food, the phytoplankton (Tetraselmis tetrathele), the brown algae (Eisenia bicyclis) and the viscera of abalone (Haliotis discus) were fed to bivalves, herbivorous gastropods and carnivorous molluscs, respectively. After single feeding of the labelled food with the nuclides, retention of the nuclides in whole body of the organisms was followed for several weeks or more. The organisms showed relatively high retention of the nuclides in whole body, except {sup 137}Cs and {sup 54}Mn. Retention of {sup 137}Cs and {sup 54}Mn in the organisms one day after feeding of radioactive food was lower than 25% of the radioactivity dosed. (author).

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

The miRNA biogenesis in marine bivalves

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Umberto Rosani

2016-03-01

Full Text Available Small non-coding RNAs include powerful regulators of gene expression, transposon mobility and virus activity. Among the various categories, mature microRNAs (miRNAs guide the translational repression and decay of several targeted mRNAs. The biogenesis of miRNAs depends on few gene products, essentially conserved from basal to higher metazoans, whose protein domains allow specific interactions with dsRNA. Here, we report the identification of key genes responsible of the miRNA biogenesis in 32 bivalves, with particular attention to the aquaculture species Mytilus galloprovincialis and Crassostrea gigas. In detail, we have identified and phylogenetically compared eight evolutionary conserved proteins: DROSHA, DGCR8, EXP5, RAN, DICER TARBP2, AGO and PIWI. In mussels, we recognized several other proteins participating in the miRNA biogenesis or in the subsequent RNA silencing. According to digital expression analysis, these genes display low and not inducible expression levels in adult mussels and oysters whereas they are considerably expressed during development. As miRNAs play an important role also in the antiviral responses, knowledge on their production and regulative effects can shed light on essential molecular processes and provide new hints for disease prevention in bivalves.

Tinjauan Keanekaragaman Moluska Air Tawar Di Beberapa Situ Di DAS Ciliwung - Cisadane [Study on the Freshwater Mollusc Diversity of the Small Lakes Along Ciliwung and Cisadane Rivers

OpenAIRE

Marwoto, Ristiyanti M; Isnaningsih, Nur R

2014-01-01

The freshwater molluscs (snails and bivalves) can be found in many type of water course either flowing or stagnant water. Some of them have survived living in bad condition such as polluted water. There are 199 situ (small lakes) in Jabodetabek (Jakarta, Bogor, Depok, Tangerang, Bekasi) have been reported but only 20 % were in good condition, even 12% have dissapeared that caused by silting up of the situ. The aim of the study was to evaluate the diversity of the molluscs as well as to know t...

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

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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.

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

Science.gov (United States)

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

2016-12-01

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

Soundscapes and Larval Settlement: Larval Bivalve Responses to Habitat-Associated Underwater Sounds.

Science.gov (United States)

Eggleston, David B; Lillis, Ashlee; Bohnenstiehl, DelWayne R

2016-01-01

We quantified the effects of habitat-associated sounds on the settlement response of two species of bivalves with contrasting habitat preferences: (1) Crassostrea virginicia (oyster), which prefers to settle on other oysters, and (2) Mercenaria mercenaria (clam), which settles on unstructured habitats. Oyster larval settlement in the laboratory was significantly higher when exposed to oyster reef sound compared with either off-reef or no-sound treatments. Clam larval settlement did not vary according to sound treatments. Similar to laboratory results, field experiments showed that oyster larval settlement in "larval housings" suspended above oyster reefs was significantly higher compared with off-reef sites.

Unusual conservation of mitochondrial gene order in Crassostrea oysters: evidence for recent speciation in Asia

Science.gov (United States)

2010-01-01

Background Oysters are morphologically plastic and hence difficult subjects for taxonomic and evolutionary studies. It is long been suspected, based on the extraordinary species diversity observed, that Asia Pacific is the epicenter of oyster speciation. To understand the species diversity and its evolutionary history, we collected five Crassostrea species from Asia and sequenced their complete mitochondrial (mt) genomes in addition to two newly released Asian oysters (C. iredalei and Saccostrea mordax) for a comprehensive analysis. Results The six Asian Crassostrea mt genomes ranged from 18,226 to 22,446 bp in size, and all coded for 39 genes (12 proteins, 2 rRNAs and 25 tRNAs) on the same strand. Their genomes contained a split of the rrnL gene and duplication of trnM, trnK and trnQ genes. They shared the same gene order that differed from an Atlantic sister species by as many as nine tRNA changes (6 transpositions and 3 duplications) and even differed significantly from S. mordax in protein-coding genes. Phylogenetic analysis indicates that the six Asian Crassostrea species emerged between 3 and 43 Myr ago, while the Atlantic species evolved 83 Myr ago. Conclusions The complete conservation of gene order in the six Asian Crassostrea species over 43 Myr is highly unusual given the remarkable rate of rearrangements in their sister species and other bivalves. It provides strong evidence for the recent speciation of the six Crassostrea species in Asia. It further indicates that changes in mt gene order may not be strictly a function of time but subject to other constraints that are presently not well understood. PMID:21189147

Shell extracts of the edible mussel and oyster induce an enhancement of the catabolic pathway of human skin fibroblasts, in vitro.

Science.gov (United States)

Latire, Thomas; Legendre, Florence; Bouyoucef, Mouloud; Marin, Frédéric; Carreiras, Franck; Rigot-Jolivet, Muriel; Lebel, Jean-Marc; Galéra, Philippe; Serpentini, Antoine

2017-10-01

Mollusc shells are composed of more than 95% calcium carbonate and less than 5% organic matrix consisting mostly of proteins, glycoproteins and polysaccharides. In this study, we investigated the effects of matrix macromolecular components extracted from the shells of two edible molluscs of economic interest, i.e., the blue mussel Mytilus edulis and the Pacific oyster Crassostrea gigas. The potential biological activities of these organic molecules were analysed on human dermal fibroblasts in primary culture. Our results demonstrate that shell extracts of the two studied molluscs modulate the metabolic activities of the cells. In addition, the extracts caused a decrease of type I collagen and a concomitant increase of active MMP-1, both at the mRNA and the protein levels. Therefore, our results suggest that shell extracts from M. edulis and C. gigas contain molecules that promote the catabolic pathway of human dermal fibroblasts. This work emphasises the potential use of these shell matrices in the context of anti-fibrotic strategies, particularly against scleroderma. More generally, it stresses the usefulness to valorise bivalve shells that are coproducts of shellfish farming activity.

The Mg - SST relationship in mollusc shells: is there a rule? Examples from three tropical species

Science.gov (United States)

Lazareth, C. E.; Guzmán, N.; Lecornec, F.; Cabioch, G.; Ortlieb, L.

2009-04-01

The geochemistry of mollusc shells is currently viewed as a powerful tool for paleoenvironmental reconstructions. Indeed, molluscs are ubiquitous animals, with a worldly geographical and environmental distribution, providing various environmental records. Moreover, mollusc shells are abundantly found in fossil and archaeological settings. In the paleoclimatic reconstructions, the sea-surface temperatures (SST) are a key parameter. If shell stable oxygen isotope signatures can provide accurate SST records, this proxy is also influenced by the water isotopic composition. To find another tracer which would depend on the SST solely, the relationship between Mg content changes in mollusc shell and SST has been investigated for a few years. Nevertheless, if the reliability of shell Mg as SST tracer has been proven in some species, this is clearly not a "universal" and definitive rule. To reconstruct the past tropical SSTs, Mg calibration studies were undertaken on Concholepas concholepas (gastropod, South America), Protothaca thaca (bivalve, South America) and Tridacna squamosa (bivalve, New Caledonia). The very high-resolution (infra-daily) analyses of the C. concholepas gastropod revealed a significant metabolism control, at the nyctemeral scale, on the Mg incorporation into the calcite shell layer. Over a two months period, the Mg fluctuations in C. concholepas shell do not match with the SST instrumental measurements. Mg content changes along the aragonitic shell growth axis of several living P. thaca from a same Peruvian site are significantly different indicating no relationship between Mg and SST. The Mg variations measured in a Chilean P. thaca shell are, surprisingly, similar to variations of the instrumental SST. Unless this quite reliable relationship between P. thaca shell and SST is confirmed, and that the inter-site difference in Mg response to environmental forcing is understood, P. thaca shell Mg cannot be used as SST proxy. Lastly, a preliminary work

Spatial genetic features of eastern oysters (Crassostrea virginica Gmelin) in the Gulf of Mexico: northward movement of a secondary contact zone

OpenAIRE

Anderson, Joel D; Karel, William J; Mace, Christopher E; Bartram, Brian L; Hare, Matthew P

2014-01-01

The eastern oyster (Crassostrea virginica Gmelin) is an economically and ecologically valuable marine bivalve occurring in the Gulf of Mexico. This study builds upon previous research that identified two divergent populations of eastern oysters in the western Gulf of Mexico. Allelic and genotypic patterns from 11 microsatellite markers were used to assess genetic structure and migration between the previously described oyster populations in Texas. The main findings are as follows: (1) there a...

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

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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.

Enterococcus spp. Resistant to Multiple Antimicrobial Drugs and Determination of Fecal Contamination Levels in Mangrove Oysters (Crassostrea rhizophorae)

OpenAIRE

Rubião, Cynthia Annes; Franco, Robson Maia; Mesquita, Eliana de Fátima Marques de; Miguel, Marco Antonio Lemos; Cabral, Claudius Couto; Fonseca, Ana Beatriz Monteiro

2017-01-01

ABSTRACT The aim of this study was to determine and compare the Most Probable Number (MPN) of Total Coliforms (TC), Escherichia coli and Enterococcus spp. and to characterize the antimicrobial resistance profiles of Enterococcus spp. isolated from oysters collected in the Barra de Guaratiba Mangrove, Rio de Janeiro, Brazil. The enumeration of E. coli has been used to indicate fecal contamination and hygienic-sanitary conditions of bivalve molluscs. Enterococci are capable to transfer several ...

Contamination in sediments, bivalves and sponges of McMurdo Sound, Antarctica

Energy Technology Data Exchange (ETDEWEB)

Negri, Andrew [Australian Institute of Marine Science, PMB 3, Townsville, Qld (Australia)]. E-mail: a.negri@aims.gov.au; Burns, Kathryn [Australian Institute of Marine Science, PMB 3, Townsville, Qld (Australia); Boyle, Steve [Australian Institute of Marine Science, PMB 3, Townsville, Qld (Australia); Brinkman, Diane [Australian Institute of Marine Science, PMB 3, Townsville, Qld (Australia); Webster, Nicole [Australian Institute of Marine Science, PMB 3, Townsville, Qld (Australia); Biological Sciences, University of Canterbury, Christchurch (New Zealand)

2006-10-15

This study examined the concentrations of total hydrocarbons (THC), polychlorinated biphenyls (PCB), polyaromatic hydrocarbons (PAH), and trace metals (Cu, Zn, Cd, Pb, Hg and As) in marine sediments off Scott Base (NZ) and compared them with sediments near the highly polluted McMurdo Station (US) as well as less impacted sites including Turtle Rock and Cape Evans. The Antarctic mollusc, Laternula elliptica and three common sponge species were also analysed for trace metals. The mean THC concentration in sediments from Scott Base was 3 fold higher than the pristine site, Turtle Rock, but 10 fold lower than samples from McMurdo Station. McMurdo Station sediments also contained the highest concentrations of PAHs, PCBs and the trace metals, Cu, Zn, Pb, Cd and Hg. Copper was significantly higher in bivalves from McMurdo Station than other sites. Trace metal concentrations in sponges were generally consistent within sites but no spatial patterns were apparent. - Analyses of Antarctic marine sediments, bivalves and sponges revealed strong PAH, PCB and trace metal gradients in McMurdo Sound.

Contamination in sediments, bivalves and sponges of McMurdo Sound, Antarctica

International Nuclear Information System (INIS)

Negri, Andrew; Burns, Kathryn; Boyle, Steve; Brinkman, Diane; Webster, Nicole

2006-01-01

This study examined the concentrations of total hydrocarbons (THC), polychlorinated biphenyls (PCB), polyaromatic hydrocarbons (PAH), and trace metals (Cu, Zn, Cd, Pb, Hg and As) in marine sediments off Scott Base (NZ) and compared them with sediments near the highly polluted McMurdo Station (US) as well as less impacted sites including Turtle Rock and Cape Evans. The Antarctic mollusc, Laternula elliptica and three common sponge species were also analysed for trace metals. The mean THC concentration in sediments from Scott Base was 3 fold higher than the pristine site, Turtle Rock, but 10 fold lower than samples from McMurdo Station. McMurdo Station sediments also contained the highest concentrations of PAHs, PCBs and the trace metals, Cu, Zn, Pb, Cd and Hg. Copper was significantly higher in bivalves from McMurdo Station than other sites. Trace metal concentrations in sponges were generally consistent within sites but no spatial patterns were apparent. - Analyses of Antarctic marine sediments, bivalves and sponges revealed strong PAH, PCB and trace metal gradients in McMurdo Sound

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.

The Mediterranean stony coral Cladocora caespitosa (Linnaeus, 1767) as habitat provider for molluscs: colony size effect

Science.gov (United States)

Pitacco, Valentina; Crocetta, Fabio; Orlando-Bonaca, Martina; Mavrič, Borut; Lipej, Lovrenc

2017-11-01

The stony coral Cladocora caespitosa (Linnaeus, 1767) is an important Mediterranean habitat builder, whose survival is now being threatened by human activities and possibly natural events such as mass mortality and bleaching. We characterized the mollusc assemblage associated with colonies in the Gulf of Trieste (northern Adriatic Sea) and then tested whether the number of mollusc species increases in relation with colony size, following a Species-Area Relationship (SAR) model. At least 62 taxa were found in association with coral colonies, with bivalves constituting the dominant group. More than half of the 3034 specimens encountered were juveniles. Mollusc taxa richness increased with increasing C. caespitosa colony size according to the power-function model, whilst the analyses of trophic and functional groups supports the hypothesis of at least two factors underlying SAR (area per se and habitat diversity). Our results confirmed the importance of C. caespitosa for benthic communities, indicating that larger colonies support higher biodiversity, and suggesting that C. caespitosa is the most important habit builder among Mediterranean cnidarians, having also an influential function as a natural nursery ground. These results underline the necessity of new investigations aimed at filling gaps in our knowledge and planning new measures to protect the species.

DNA methylation patterns provide insight into epigenetic regulation in the Pacific oyster (Crassostrea gigas

Directory of Open Access Journals (Sweden)

Gavery Mackenzie R

2010-08-01

Full Text Available Abstract Background DNA methylation is an epigenetic mechanism with important regulatory functions in animals. While the mechanism itself is evolutionarily ancient, the distribution and function of DNA methylation is diverse both within and among phylogenetic groups. Although DNA methylation has been well studied in mammals, there are limited data on invertebrates, particularly molluscs. Here we characterize the distribution and investigate potential functions of DNA methylation in the Pacific oyster (Crassostrea gigas. Results Methylation sensitive PCR and bisulfite sequencing PCR approaches were used to identify CpG methylation in C. gigas genes and demonstrated that this species possesses intragenic methylation. In silico analysis of CpGo/e ratios in publicly available sequence data suggests that DNA methylation is a common feature of the C. gigas genome, and that specific functional categories of genes have significantly different levels of methylation. Conclusions The Pacific oyster genome displays intragenic DNA methylation and contains genes necessary for DNA methylation in animals. Results of this investigation suggest that DNA methylation has regulatory functions in Crassostrea gigas, particularly in gene families that have inducible expression, including those involved in stress and environmental responses.

Microplastics in bivalves cultured for human consumption.

Science.gov (United States)

Van Cauwenberghe, Lisbeth; Janssen, Colin R

2014-10-01

Microplastics are present throughout the marine environment and ingestion of these plastic particles (microplastics in two species of commercially grown bivalves: Mytilus edulis and Crassostrea gigas. Microplastics were recovered from the soft tissues of both species. At time of human consumption, M. edulis contains on average 0.36 ± 0.07 particles g(-1) (wet weight), while a plastic load of 0.47 ± 0.16 particles g(-1) ww was detected in C. gigas. As a result, the annual dietary exposure for European shellfish consumers can amount to 11,000 microplastics per year. The presence of marine microplastics in seafood could pose a threat to food safety, however, due to the complexity of estimating microplastic toxicity, estimations of the potential risks for human health posed by microplastics in food stuffs is not (yet) possible. Copyright © 2014 Elsevier Ltd. All rights reserved.

Butyltin compounds in sediment and molluscs from the shipping strait between Denmark and Sweden

International Nuclear Information System (INIS)

Strand, Jakob; Jacobsen, Jens A.; Pedersen, Britta; Granmo, Aake

2003-01-01

The deposit feeding bivalve Nuculana pernula is a suitable for monitoring bioavailability of TBT in sediment along a major shipping route. - The distribution of tributyltin (TBT) contamination in the subtidal zone of the waters between Denmark and Sweden was investigated in relation to major international shipping lanes. Sediment and different benthic molluscs were sampled in transects along and perpendicularly to the shipping lanes in the Sound (Oresund) and the Kattegat/Skagerrak region. The samples were analysed for TBT and its degradation products, dibutyltin (DBT) and monobutyltin (MBT), using GC-PFPD. In sediments, the TBT concentration ranged from -1 dry weight (dw) with a strong correlation between the TBT concentration and the organic fraction in sediment (r 2 =0.90) in the samples collected in the Sound, where the highest concentrations were found. This relationship was not observed in the samples from the Kattegat because the TBT concentration in most sediment samples was below the limit of detection. In the molluscs, TBT and its degradation products were detected in all samples from the entire area with concentrations ranging from 8.1 ng g -1 dw in Buccinum undatum to 1316 ng g -1 dw in Nuculana pernula. The deposit-feeding bivalve N. pernula was found to have a particularly high accumulation potential for TBT. In addition, a strong correlation between TBT concentrations in sediment and N. pernula was found. Therefore this species seems to be an ideal organism for monitoring sediment contamination. The TBT concentration in N. pernula was found to decrease gradually along the shipping lanes from the Sound, through the Kattegat and into the Skagerrak

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

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...... a tidal cycle was estimated at 45 838 m3, of which C. gigas and M. edulis contributed 9169 and 36 669 m3, respectively. Therefore, M. edulis contributed 4 times as much as C. gigas to the bivalve bed’s clearance, and the 2 bivalves were estimated to clear the water volume 1.9 times during each tidal cycle....... However, the estimated water column cleared during low tide is overestimated due to phytoplankton depletion. Hence, it is concluded that the bivalve bed clears the water close to 1 time each tidal cycle. This, together with a low dry weight of soft parts, indicates that the bivalve bed, in general...

Mollusc and brachiopod skeletal hardparts: Problematic archives of past seawater properties (Invited)

Science.gov (United States)

Immenhauser, A.; Schone, B. R.; Hoffmann, R.; Niedermayr, A.

2013-12-01

Biomineralized exo- or endoskeletons of fossil marine invertebrates are widespread and diverse components of the Phanerozoic rock record of Earth's past and present oceans. Exoskeletons serve as protection against environmental pressure or predators, whilst endoskeletons may act as support or serves as an attachment for muscles and ligaments and hence as a mechanism for transmitting muscular forces. Biogenic hardparts represent sophisticated products resulting from the hierarchical interaction of inorganic minerals (95%) and macromolecular organic matrix, forming commonly less than 5%. The significance of biogenic carbonate archives lies in the time-resolved growth-increments and their respective multi-proxy geochemical signatures that have been widely used to assess past oceanic seawater properties. We here compile and review published work dealing with crystallization pathways of skeletal hardparts secreted by molluscs (i.e., bivalves and cephalopods) as well as brachiopods as widely used archives of ancient neritic epeiric settings. Bivalves and cephalopods (e.g., extinct ammonoids and belemnites and extant Sepia, Nautilus and Spirula) all form accretionary calcitic, aragonitic or vateritic skeletal hardparts. Despite the fact that molluscs and brachiopods form part of very different branches of the animal phylogenetic tree, their biomineralization strategies are surprisingly similar. Our main focus lies in a critical assessment of the complex pathways of ions and aquo-complexes from their source (seawater) to the final product (biomineral). We do this as an attempt to critically test the commonly held hypothesis that many fossil shell hardparts precipitated, under favourable conditions and pending subsequent diagenetic alteration, in equilibrium with seawater. Two main observations stand out: (1) the present knowledge on pathways and mechanisms (e.g., ion channel trans-membrane or endocytosis and vesicle transport, precursor mineralogies etc.) is surprisingly

Streptomyces effect on the bacterial microbiota associated to Crassostrea sikamea oyster.

Science.gov (United States)

García Bernal, M; Trabal Fernández, N; Saucedo Lastra, P E; Medina Marrero, R; Mazón-Suástegui, J M

2017-03-01

To determine the composition and diversity of the microbiota associated to Crassostrea sikamea treated during 30 days with Streptomyces strains N7 and RL8. DNA was extracted from oysters followed by 16S rRNA gene amplification and pyrosequencing. The highest and lowest species diversity richness was observed in the initial and final control group, whereas Streptomyces-treated oysters exhibited intermediate values. Proteobacteria was the most abundant phylum (81·4-95·1%), followed by Bacteroidetes, Actinobacteria and Firmicutes. The genera Anderseniella, Oceanicola, Roseovarius, Ruegeria, Sulfitobacter, Granulosicoccus and Marinicella encompassed the core microbiota of all experimental groups. The genus Bacteriovorax was detected in all groups except in the final control and the depurated N7, whereas Vibrio remained undetected in all Streptomyces-treated groups. RL8 was the only group that harboured the genus Streptomyces in its microbiota. Principal component analysis showed that Streptomyces strains significantly changed oyster microbiota with respect to the initial and final control. Crassostrea sikamea treated with Streptomyces showed high species diversity and a microbiota composition shift, characterized by keeping the predator genus Bacteriovorax and decreasing the pathogenic Vibrio. This is the first culture-independent study showing the effect of Streptomyces over the oyster microbiota. It also sheds light about the potential use of Streptomyces to improve mollusc health and safety for consumers after the depuration process. © 2016 The Society for Applied Microbiology.

New insights from the oyster Crassostrea rhizophorae on bivalve circulating hemocytes.

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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.

Accumulation of butyl- and phenyltin compounds in starfish and bivalves from the coastal environment of Korea

Energy Technology Data Exchange (ETDEWEB)

Shim, Won Joon [Southern Coastal Environment Research Division, Korea Ocean Research and Development Institute, Jangmok-myon 391, Geoje 656-830 (Korea, Republic of)]. E-mail: wjshim@kordi.re.kr; Yim, Un Hyuk [Southern Coastal Environment Research Division, Korea Ocean Research and Development Institute, Jangmok-myon 391, Geoje 656-830 (Korea, Republic of); Kim, Nam Sook [Southern Coastal Environment Research Division, Korea Ocean Research and Development Institute, Jangmok-myon 391, Geoje 656-830 (Korea, Republic of); Hong, Sang Hee [Southern Coastal Environment Research Division, Korea Ocean Research and Development Institute, Jangmok-myon 391, Geoje 656-830 (Korea, Republic of); Oh, Jae Ryoung [Southern Coastal Environment Research Division, Korea Ocean Research and Development Institute, Jangmok-myon 391, Geoje 656-830 (Korea, Republic of); Jeon, Joong Kyun [Department of Marine Bioscience and Technology, Kangnung National University, Kangnung 210-702 (Korea, Republic of); Okamura, Hideo [Laboratory of Marine Environment Management, Kobe University Mercantile Marine, Fukaeminami 5-1-1, Highshinada, Kobe 658-0022 (Japan)

2005-02-01

Triphenyltin (TPT) and tributyltin (TBT) concentrations were determined in two starfish species (Asteria pectinifera and Asterias amurensis), bivalves (Crassostrea gigas or Mytilus edulis), and seawater samples from sites around the coasts of Korea. Both TPT and TBT concentrations in starfish ranged from 8 to 1560 ng/g and from <2 to 797 ng/g as Sn on a dry weight basis, respectively. TPT concentration accounted for 75.4% and 86.4% of total phenyltin concentration in A. pectinifera and A. amurensis, respectively, while monobutyltin, a degradation product of TBT, accounted for 86.3% and 57.2% of total butyltin, respectively. Triphenyltin concentrations in A. pectinifera were significantly correlated to water and bivalve TPT concentrations, which implies that dietary uptake of TPT from contaminated prey as well as direct uptake from surrounding water contribute to TPT body residues in the starfish. Starfish could be target organisms for monitoring TPT compound in the marine environment, due to their high accumulation and low degradation capacity towards TPT. - Starfish are effective organisms for monitoring phenyltin contamination in the marine environment.

Accumulation of butyl- and phenyltin compounds in starfish and bivalves from the coastal environment of Korea

International Nuclear Information System (INIS)

Shim, Won Joon; Yim, Un Hyuk; Kim, Nam Sook; Hong, Sang Hee; Oh, Jae Ryoung; Jeon, Joong Kyun; Okamura, Hideo

2005-01-01

Triphenyltin (TPT) and tributyltin (TBT) concentrations were determined in two starfish species (Asteria pectinifera and Asterias amurensis), bivalves (Crassostrea gigas or Mytilus edulis), and seawater samples from sites around the coasts of Korea. Both TPT and TBT concentrations in starfish ranged from 8 to 1560 ng/g and from <2 to 797 ng/g as Sn on a dry weight basis, respectively. TPT concentration accounted for 75.4% and 86.4% of total phenyltin concentration in A. pectinifera and A. amurensis, respectively, while monobutyltin, a degradation product of TBT, accounted for 86.3% and 57.2% of total butyltin, respectively. Triphenyltin concentrations in A. pectinifera were significantly correlated to water and bivalve TPT concentrations, which implies that dietary uptake of TPT from contaminated prey as well as direct uptake from surrounding water contribute to TPT body residues in the starfish. Starfish could be target organisms for monitoring TPT compound in the marine environment, due to their high accumulation and low degradation capacity towards TPT. - Starfish are effective organisms for monitoring phenyltin contamination in the marine environment

The ecology, evolution, impacts and management of host-parasite interactions of marine molluscs.

Science.gov (United States)

Coen, Loren D; Bishop, Melanie J

2015-10-01

Molluscs are economically and ecologically important components of aquatic ecosystems. In addition to supporting valuable aquaculture and wild-harvest industries, their populations determine the structure of benthic communities, cycling of nutrients, serve as prey resources for higher trophic levels and, in some instances, stabilize shorelines and maintain water quality. This paper reviews existing knowledge of the ecology of host-parasite interactions involving marine molluscs, with a focus on gastropods and bivalves. It considers the ecological and evolutionary impacts of molluscan parasites on their hosts and vice versa, and on the communities and ecosystems in which they are a part, as well as disease management and its ecological impacts. An increasing number of case studies show that disease can have important effects on marine molluscs, their ecological interactions and ecosystem services, at spatial scales from centimeters to thousands of kilometers and timescales ranging from hours to years. In some instances the cascading indirect effects arising from parasitic infection of molluscs extend well beyond the temporal and spatial scales at which molluscs are affected by disease. In addition to the direct effects of molluscan disease, there can be large indirect impacts on marine environments resulting from strategies, such as introduction of non-native species and selective breeding for disease resistance, put in place to manage disease. Much of our understanding of impacts of molluscan diseases on the marine environment has been derived from just a handful of intensively studied marine parasite-host systems, namely gastropod-trematode, cockle-trematode, and oyster-protistan interactions. Understanding molluscan host-parasite dynamics is of growing importance because: (1) expanding aquaculture; (2) current and future climate change; (3) movement of non-native species; and (4) coastal development are modifying molluscan disease dynamics, ultimately leading to

Novel Microsatellite Markers for Brazilian Mangrove Oysters ( Crassostrea gasar and their Cross-Amplification in Crassostrea rhizophorae

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Renata do Socorro Corrêa Baldez

2016-08-01

Full Text Available ABSTRACT A microsatellite CT/GT enriched genomic library was developed for Crassostrea gasar and twelve new polymorphic loci were isolated and characterized. The markers were successfully amplified from 25 individuals of Crassostrea gasar and 11 cross-amplified individuals of Crassostrea rhizophorae. There was no evidence of linkage between loci in either species.

Lipids from the nacreous and prismatic layers of two Pteriomorpha Mollusc shells

Science.gov (United States)

Farre, B.; Dauphin, Y.

2009-04-01

Mollusc shells are the best-known Ca-carbonate biominerals. They are commonly described as a mineralized two layered structure: an outer layer composed of calcite prismatic units, and an internal layer composed of tablets of aragonite: the nacreous layer. An external organic layer (periostracum) is present in most taxa. However, the most common structure in the Mollusc shell is the aragonite crossed lamellar layer, but aragonite prisms, calcite foliated layers and homogeneous layers have been also described by Boggild (1930) in all the Mollusc orders. Since, more detailed descriptions of Bivalve shells have been done (Taylor et al., 1969, 1973). Despite the nacroprismatic arrangement is rare, calcite prismatic and aragonite nacreous layers are the best studied because of their simple 3D structure and large units. Among these Molluscs, some Bivalve species composed of these two layers are of commercial interest, such as the pearl oyster, Pinctada margaritifera, cultivated in French Polynesia to produce black pearls. It is well established that Mollusc shells are composite structures of organic and inorganic components (Hatchett, 1799; Grégoire et al., 1955; Beedham, 1958; Simkiss, 1965; Mutvei, 1969; Cuif et al., 1980; Berman et al., 1993; Kobayashi and Samata, 2006). Numerous studies are concerned with the organic matrix of the shell. Organic components are commonly obtained after a strong or mild decalcification process. They are said to consist of both a soluble and insoluble fraction. The main part of studies is dedicated to the soluble components, and among them, proteins (Grégoire et al., 1955; Grégoire, 1961; Krampitz et al., 1976; Samata et al., 1980, 2004; Weiner, 1983; Miyamoto et al., 2006). Despite the pioneering work of Wada (1980) sugars are usually neglected despite their role in biomineralization. The third component of the organic matrix of calcareous biominerals is lipids. To date, there is a paucity of information concerning the presence

A biomonitoring study: trace metals in algae and molluscs from Tyrrhenian coastal areas

International Nuclear Information System (INIS)

Conti, M.E.; Cecchetti, Gaetano

2003-01-01

Marine organisms were evaluated as possible biomonitors of heavy metal contamination in marine coastal areas. Concentrations of Cd, Cr, Cu, Pb, and Zn were measured in the green algae Ulva lactuca L., the brown algae Padina pavonica (L.) Thivy, the bivalve mollusc Mytilus galloprovincialis Lamarck, and the two gastropod molluscs Monodonta turbinata Born and Patella cerulea L. collected at six coastal stations in the area of the Gulf of Gaeta (Tyrrhenian Sea, central Italy). The coastal area of the Regional Park of Gianola and Monte di Scauri (a 'Protected Sea Park' area) was chosen as a control site. Seawater samples were also collected in each site to assess soluble and total metal concentrations and to gain additional information on both the environmental conditions of the area and possible bioaccumulation patterns. Metal concentrations detected in algae and molluscs did not show significant differences among all stations studied. Moreover, statistical analyses (ANOVA, multiple comparison tests, cluster analysis) showed that the Sea Park station was not significantly different from the others. The hypothesis that the Protected Sea Park would be cleaner than the others must therefore be reconsidered. Data from this study were also compared with those previously obtained from uncontaminated sites in the Sicilian Sea, Italy. The results show clearly differences between these two marine ecosystems. The species examined showed great accumulations of metals, with concentration factors (CFs) higher than 10,000 with respect to the concentrations (soluble fractions) in marine waters. Metal concentrations recorded in this area may be used for background levels for intraspecific comparison within the Tyrrhenian area, a body of water about which information is still very scarce

Preliminary Evaluation of Microbial Communities Isolated from the Calcifying Fluid of Oysters

Science.gov (United States)

Banker, R.

2016-02-01

The process of biomineralization is defined as the selective uptake of elements that are incorporated into a defined mineral structure under strict biological control. For bivalve molluscs, such as clams, oysters, and mussels, the mantle is the primary organ in control of shell deposition. Alternatively, remote calcification takes place when carbonate-precipitating microbes (e.g. sulfate reducers) colonize a shell-secreting organism and enhance the ability of the host to build shell material. The oyster syndrome is a term that describes bivalves that possess an unusual shell morphology characterized by exceptionally thick valves containing numerous chambers filled with chalky calcite. Although remote calcification via microbial metabolism has been proposed as a mechanism of chalky deposit formation in oysters, this hypothesis has not yet been rigorously investigated. Here I present data on the microbial communities found in the calcifying fluid of two oyster species; Crassostrea gigas and Ostrea lurida are examples of oysters that do and do not exhibit the oyster syndrome, respectively. Comparison of the microbiomes of these two morphological end members may provide insight into the role of microbes in the formation of chalky deposits. Results indicate that the microbial community in the surrounding water is the dominant source for bacterial taxa found in the calcifying fluid of both oyster species. Also, it appears as though C. gigas maintains a microbial community that is more similar to its ambient environment than O. lurida. These results demonstrate that the ambient aquatic environment has a guiding influence on the microbiome found in the calcifying fluid of bivalve molluscs. However, the magnitude of this effect varies among organisms, even those that are closely related.

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.

A critical examination of the possible application of zinc stable isotope ratios in bivalve mollusks and suspended particulate matter to trace zinc pollution in a tropical estuary.

Science.gov (United States)

Araújo, Daniel; Machado, Wilson; Weiss, Dominik; Mulholland, Daniel S; Boaventura, Geraldo R; Viers, Jerome; Garnier, Jeremie; Dantas, Elton L; Babinski, Marly

2017-07-01

The application of zinc (Zn) isotopes in bivalve tissues to identify zinc sources in estuaries was critically assessed. We determined the zinc isotope composition of mollusks (Crassostrea brasiliana and Perna perna) and suspended particulate matter (SPM) in a tropical estuary (Sepetiba Bay, Brazil) historically impacted by metallurgical activities. The zinc isotope systematics of the SPM was in line with mixing of zinc derived from fluvial material and from metallurgical activities. In contrast, source mixing alone cannot account for the isotope ratios observed in the bivalves, which are significantly lighter in the contaminated metallurgical zone (δ 66 Zn JMC  = +0.49 ± 0.06‰, 2σ, n = 3) compared to sampling locations outside (δ 66 Zn JMC  = +0.83 ± 0.10‰, 2σ, n = 22). This observation suggests that additional factors such as speciation, bioavailability and bioaccumulation pathways (via solution or particulate matter) influence the zinc isotope composition of bivalves. Copyright © 2017 Elsevier Ltd. All rights reserved.

THE MEDICALLY IMPORTANT MOLLUSCS OF INDONESIA

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Machfudz Djajasasmita

2012-09-01

Full Text Available At present in Indonesia 32 species of non-marine molluscs which belong to IS families have been known to be potentially of medicalor veterinary importance, since they are suspected to be capable in transmitting human and animal diseases. The brackish water family Potamididae comprises of 1 species; whereas the freshwater snails are : Viviparidae (3 sp., Ampullariidae (3 sp., Bythiniidae (1 sp.. Pomatiopsidae (1 sp., Thiaridae (7 sp., Lymnaeidae(l sp. and Planorbidae (5 sp.; freshwater bivalve are: Corbiculidae (4 sp.; land snails are: Subulinidae (2 sp., Achatinidae (1 sp. and Bradybaenidae (1 sp.; land slug: Veronicelidae (2 sp. Philomycidae (1 sp. and Limacidae (1 sp.. All are common species which can be found in the vicinity of human habitation (ponds, rice-field, ditches, gardens etc. The parasitological studies on these molluscs are rather limited, only 9 species have been studied and confirmed to be the intermediate host of parasitic nematodes and nematodes; i.e. Oncomelania hupensis lindoensis, the intermediate host of the blood fluke Schistosoma japonica in Central Sulawesi: Pila suctata, Achatina fulica and Laevicaulis alte from several places in Sumatra, Java, Sulawesi and Flores have been found to be harbouring the larvae of the nematode Angiostrongylus cantonensis, the causative agent of eosinophilic meningoencephalitis; Bellamy a rudipelis, Gyraulus sarasinorum and Corbicula lindoensis were recorded as the intermediate host of the intestinal fluke Echinostoma lindoensis in Central Sulawesi; Lymnaea rubiginosa plays an important role in the life-cycle of the cattle liver fluke Fasciola gigantica and F.hepatica, which may reduce the national meat production; and Digoniostoma truncatum from Bali has been recorded naturally infected with radiae and cercariae of Paramphistoma sp., the causative agent of the fatal paramphistomiasis of cattle. Gyraulus convexiusculus is considered to be the most likely first intermediate host of

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 P_CO₂ enhanced accumulation of Cu and Cd in the gills of mollusks. • The proteasome activities were affected by metals but robust to elevated P_CO₂. • Exposure to Cd and Cu had opposite effects on the proteasome activity. • Combined exposure to Cu and elevated P_CO₂ 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 P_CO₂ ~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 P_CO₂ 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 P_CO₂, but P_CO₂ modulated the proteasome response to metals. Cd exposure stimulated the chymotrypsin-like activity of the oyster proteasome

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...

Voyaging around nacre with the X-ray shuttle: From bio-mineralisation to prosthetics via mollusc phylogeny

International Nuclear Information System (INIS)

Chateigner, D.; Ouhenia, S.; Krauss, C.; Hedegaard, C.; Gil, O.; Morales, M.; Lutterotti, L.; Rousseau, M.; Lopez, E.

2010-01-01

Research highlights: → Nacre could be a non ancestral form of calcium carbonate in molluscs. → Texture terms as useful links to ancestors in classification. → X-ray diffraction useful for biomineralisation, phylogeny, cladistic and implantology. → Farming conditions do not influence much shell growth. → Electrodeposition of aragonite as future technique for implant coating. - Abstract: Strong textures of mollusc shell layers are utilised to provide phylogenetic information. Aragonitic and calcitic layers are the targets here, inside which nacre layers, but not only, play a specific role. At the light of the texture patterns and a parcimonious approach, nacre appears not as an ancestral form of calcium carbonate in mollusc layers. Also, from texture terms we can propose some links to ancestral fossilised species. The aragonite unit-cell distortions due to macromolecule complex insertions in the microstructures are measured on raw specimens for several aragonite layers of gastropods and bivalves. The textural information is used to provide precise structural determination of the biogenic aragonite. Such information might provide useful lights on the biomineralisation processes in the future, in cladistic approaches. Farming conditions are shown not to influence much shell textures of Helix aspersa aspersa. Closely related species exhibit globally close textures, among which three are good candidates for bone neogeneration and which textures are identical. Electrodeposition of aragonite, with inclusion of molecular extract from shell species, results in nacre-like layers exhibiting structural distortions similar to known inductive layers. X-ray diffraction experiments are shown to provide invaluable insights in testing biomineralisation and phylogenetic hypotheses.

Determination and Quantification of metals in the shells of Crassostrea virginica after the Deepwater Horizon oil spill utilizing Atomic Absorption Spectrometry.

Science.gov (United States)

Roopnarine, D.; Patel, S.; Roopnarine, P.; Giarikos, D.; Anderson, L. C.

2017-12-01

The Deepwater Horizon (DWH) oil rig explosion on April 20, 2010 resulted in the release of 685,000 tons of crude oil into the Gulf of Mexico (GOM) over a period of three months. There were obvious immediate effects, but the long-term ramifications are still being studied. The primary constituent of crude oil is hydrocarbons with other organic compounds containing nitrogen, oxygen and sulfur. There are also a number of trace metals with the most abundant frequently being iron, nickel, copper and vanadium. These do not degrade like organic materials. However, the exact composition varies among the production sites. The oil from the DWH rig was classified as light crude which is moderately volatile. Natural oil seeps occur in the environment, but the DWH spill represented an acute impact. Trace amounts of heavy metals are a normal part of the composition of marine organisms, but can be toxic in high concentrations. Bivalved molluscs bioaccumulate heavy metals in their tissues and shells, and are therefore often useful as monitors of environmental pollution. We thus used the Eastern oyster Crassostrea virginica to determine the impact of the spill by measuring the concentrations of metals in the shells utilizing flame emission atomic absorption spectrometry. We focused on the hypothesis that DWH spill exposure resulted in an increase in metal uptake into the shells. Specimens spanned the years 2010 to 2014 and ranged from Grand Isle, LA to Apalachicola Bay, Fl. Vanadium had the greatest concentration in the shells, and along with copper, cadmium, zinc and iron displayed an upward trend of increase from 2010 to 2013, with a decline in 2014. However there was unexpected variability, as the specimens from Apalachicola Bay, Fl had higher levels of vanadium when compared to those from Grand Isle, LA. Ongoing work includes an increase of sample sizes from the same geographic localities and time period.

Hepatitis A and E Viruses in Wastewaters, in River Waters, and in Bivalve Molluscs in Italy.

Science.gov (United States)

Iaconelli, M; Purpari, G; Della Libera, S; Petricca, S; Guercio, A; Ciccaglione, A R; Bruni, R; Taffon, S; Equestre, M; Fratini, M; Muscillo, M; La Rosa, Giuseppina

2015-12-01

Several studies have reported the detection of hepatitis A (HAV) and E (HEV) virus in sewage waters, indicating a possibility of contamination of aquatic environments. The objective of the present study was to assess the occurrence of HAV and HEV in different water environments, following the route of contamination from raw sewage through treated effluent to the surface waters receiving wastewater discharges . Bivalve molluscan shellfish samples were also analyzed, as sentinel of marine pollution. Samples were tested by RT-PCR nested type in the VP1/2A junction for HAV, and in the ORF1 and ORF2 regions for HEV. Hepatitis A RNA was detected in 12 water samples: 7/21 (33.3%) raw sewage samples, 3/21 (14.3%) treated sewage samples, and 2/27 (7.4%) river water samples. Five sequences were classified as genotype IA, while the remaining 7 sequences belonged to genotype IB. In bivalves, HAV was detected in 13/56 samples (23.2%), 12 genotype IB and one genotype IA. Whether the presence of HAV in the matrices tested indicates the potential for waterborne and foodborne transmission is unknown, since infectivity of the virus was not demonstrated. HEV was detected in one raw sewage sample and in one river sample, both belonging to genotype 3. Sequences were similar to sequences detected previously in Italy in patients with autochthonous HEV (no travel history) and in animals (swine). To our knowledge, this is the first detection of HEV in river waters in Italy, suggesting that surface water can be a potential source for exposure .

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

International Nuclear Information System (INIS)

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

2014-01-01

Highlights: • Elevated P CO 2 enhanced accumulation of Cu and Cd in the gills of mollusks. • The proteasome activities were affected by metals but robust to elevated P CO 2 . • Exposure to Cd and Cu had opposite effects on the proteasome activity. • Combined exposure to Cu and elevated P CO 2 negatively affected energy status. - Abstract: Increased anthropogenic emission of CO 2 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 CO 2 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 CO 2 (P CO 2 ∼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 P CO 2 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 P CO 2 , but P CO 2 modulated the proteasome response to metals. Cd exposure stimulated the chymotrypsin-like activity of the oyster proteasome at all CO 2 levels. In contrast, trypsin- and caspase-like activities of

Near infra-red spectroscopy quantitative modelling of bivalve protein, lipid and glycogen composition using single-species versus multi-species calibration and validation sets

Science.gov (United States)

Bartlett, Jill K.; Maher, William A.; Purss, Matthew B. J.

2018-03-01

Near infrared spectroscopy (NIRS) quantitative modelling was used to measure the protein, lipid and glycogen composition of five marine bivalve species (Saccostrea glomerata, Ostrea angasi, Crassostrea gigas, Mytilus galloprovincialis and Anadara trapezia) from multiple locations and seasons. Predictive models were produced for each component using individual species and aggregated sample populations for the three oyster species (S. glomerata, O. angasi and C. gigas) and for all five bivalve species. Whole animal tissues were freeze dried, ground to > 20 μm and scanned by NIRS. Protein, lipid and glycogen composition were determined by traditional chemical analyses and calibration models developed to allow rapid NIRS-measurement of these components in the five bivalve species. Calibration modelling was performed using wavelet selection, genetic algorithms and partial least squares analysis. Model quality was assessed using RPIQ and RMESP. For protein composition, single species model results had RPIQ values between 2.4 and 3.5 and RMSEP between 8.6 and 18%, the three oyster model had an RPIQ of 2.6 and an RMSEP of 10.8% and the five bivalve species had an RPIQ of 3.6 and RMSEP of 8.7% respectively. For lipid composition, single species models achieved RPIQ values between 2.9 and 5.3 with RMSEP between 9.1 and 11.2%, the oyster model had an RPIQ of 3.6 and RMSEP of 6.8 and the five bivalve model had an RPIQ of 5.2 and RMSEP of 6.8% respectively. For glycogen composition, the single species models had RPIQs between 3.8 and 18.9 with RMSEP between 3.5 and 9.2%, the oyster model had an RPIQ of 5.5 and RMSEP of 7.1% and the five bivalve model had an RPIQ of 4 and RMSEP of 7.6% respectively. Comparison between individual species models and aggregated models for three oyster species and five bivalve species for each component indicate that aggregating data from like species produces high quality models with robust and reliable quantitative application. The benefit of

Comparative transcriptome analysis of two oysters, Crassostrea gigas and Crassostrea hongkongensis provides insights into adaptation to hypo-osmotic conditions.

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Xuelin Zhao

Full Text Available Environmental salinity creates a key barrier to limit the distribution of most aquatic organisms. Adaptation to osmotic fluctuation is believed to be a factor facilitating species diversification. Adaptive evolution often involves beneficial mutations at more than one locus. Bivalves hold great interest, with numerous species living in waters, as osmoconformers, who maintain the osmotic pressure balance mostly by free amino acids. In this study, 107,076,589 reads from two groups of Crassostrea hongkongensis were produced and the assembled into 130,629 contigs. Transcripts putatively involved in stress-response, innate immunity and cell processes were identified according to Gene ontology and KEGG pathway analyses. Comparing with the transcriptome of C. gigas to characterize the diversity of transcripts between species with osmotic divergence, we identified 182,806 high-quality single nucleotide polymorphisms (SNPs for C. hongkongensis, and 196,779 SNPs for C. gigas. Comparison of 11,602 pairs of putative orthologs allowed for identification of 14 protein-coding genes that experienced strong positive selection (Ka/Ks>1. In addition, 45 genes that may show signs of moderate positive selection (1 ≥ Ka/Ks>0.5 were also identified. Based on Ks ratios and divergence time between the two species published previously, we estimated a neutral transcriptome-wide substitution mutation rate of 1.39 × 10(-9 per site per year. Several genes were differentially expressed across the control and treated groups of each species. This is the first time to sequence the transcriptome of C. hongkongensis and provide the most comprehensive transcriptomic resource available for it. The increasing amount of transcriptome data on Crassostrea provides an excellent resource for phylogenetic analysis. A large number of SNPs identified in this work are expected to provide valuable resources for future marker and genotyping assay development. The analysis of natural

Growth, mortality and susceptibility of oyster Crassostrea spp. to Perkinsus spp. infection during on growing in northeast Brazil

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Marcos Paiva Scardua

2017-11-01

Full Text Available Abstract Crassostrea rhizophorae and C. gasar oysters are cultivated in the northeast region. Perkinsus parasites infect bivalves, and their effects on oysters from tropical regions are poorly understood. This study evaluated the impact of Perkinsus infection on the productive traits of native oysters. Oysters were sampled bimonthly during 7 months, from July 2010 to February 2011, to evaluate growth rate, mortality and shell color patterns (white and dark-gray (n = 500, and to determine the prevalence and intensity of Perkinsus (n = 152. Perkinsus and Crassostrea species were determined using molecular tools. Results showed that most dark-gray (90%, n = 20 and white (67%, n = 18 oysters were C. gasar and C. rhizophorae, respectively. Oysters showed a high growth rate and moderate cumulative mortality (44%. C. gasar oysters grew better and showed lower mortality and lower incidence of Perkinsus compared to C. rhizophorae. The mean prevalence of Perkinsus was moderate (48%, but the infection intensity was light (2.2. Perkinsosis affected very small oysters (19.4 mm. In conclusion, native oysters, especially C. gasar, have a great potential for culture, mortality is not associated with perkinsosis, and the shell color of oysters can be used to improve selection for spats with better performance.

ICP-MS: suitable method to study the metals distribution in estuarine regions

International Nuclear Information System (INIS)

Vasconcelos, Danilo C.; Oliveira, Arno H.; Santos, Silvio J. dos; Brito, Veronica F.O.; Severo, Maria Isabel G.

2005-01-01

Anthropogenic inputs of pollutants such as heavy metals into the marine environment have increased their levels to large extents within past a few decades. These pollutants tend to accumulate in the bottom sediments. As a result, ecosystems such as seaports or other industrialized coastal areas that have chronic inputs of metals have highly contaminated sediments. This characteristic has led to concerns over the ecological effects that may be associated with sediment quality. Of particular concern are toxic effects and the potential for bioaccumulation of metals in biota exposed to the sediments. The bivalves Crassostrea rhizophorae, Lucina pectinata and Mytella falcata have been used as biomonitors of trace metal contamination in two estuaries from Ilheus city, Bahia state, in Brazil. Bivalves, sediment and water samples were collected in March 2004 in Acuipe and Rio do Engenho mangroves. The proposed technique to analyze the studied matrices was the inductively coupled plasma mass spectrometry (ICP-MS). The results suggested that the studied molluscs are bioaccumulators of metals and showed the Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) as an adequate technique to determine a large range of inorganic elements, because its high sensibility and low detection limits. (author)

ICP-MS: suitable method to study the metals distribution in estuarine regions; ICP-MS metodo adequado para o estudo da distribuicao de metais em regioes estuarinas

Energy Technology Data Exchange (ETDEWEB)

Vasconcelos, Danilo C.; Oliveira, Arno H. [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear]. E-mail: danilochagas@yahoo.com.br; heeren@nuclear.ufmg.br; Santos, Silvio J. dos; Brito, Veronica F.O.; Severo, Maria Isabel G. [Universidade Estadual de Santa Cruz, Ilheus, BA (Brazil). Dept. de Ciencias Biologicas

2005-07-01

Anthropogenic inputs of pollutants such as heavy metals into the marine environment have increased their levels to large extents within past a few decades. These pollutants tend to accumulate in the bottom sediments. As a result, ecosystems such as seaports or other industrialized coastal areas that have chronic inputs of metals have highly contaminated sediments. This characteristic has led to concerns over the ecological effects that may be associated with sediment quality. Of particular concern are toxic effects and the potential for bioaccumulation of metals in biota exposed to the sediments. The bivalves Crassostrea rhizophorae, Lucina pectinata and Mytella falcata have been used as biomonitors of trace metal contamination in two estuaries from Ilheus city, Bahia state, in Brazil. Bivalves, sediment and water samples were collected in March 2004 in Acuipe and Rio do Engenho mangroves. The proposed technique to analyze the studied matrices was the inductively coupled plasma mass spectrometry (ICP-MS). The results suggested that the studied molluscs are bioaccumulators of metals and showed the Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) as an adequate technique to determine a large range of inorganic elements, because its high sensibility and low detection limits. (author)

Determination of the variability of both hydrophilic and lipophilic toxins in endemic wild bivalves and carnivorous gastropods from the southern part of Chile.

Science.gov (United States)

Zamorano, Ruben; Marín, Michelle; Cabrera, Fabiola; Figueroa, Diego; Contreras, Cristóbal; Barriga, Andrés; Lagos, Néstor; García, Carlos

2013-01-01

The aim of this study was to analyse and determine the composition of paralytic shellfish poisoning (PSP) toxins and lipophilic toxins in the Region of Aysén, Chile, in wild endemic mussels (Mytilus chilensis, Venus antiqua, Aulacomya ater, Choromytilus chorus, Tagelus dombeii and Gari solida) and in two endemic carnivorous molluscs species (Concholepas concholepas and Argobuccinum ranelliforme). PSP-toxin contents were determined by using HPLC with fluorescence detection, while lipophilic toxins were determined by using LC-MS/MS. Mean concentrations for the total of PSP toxins were in the range 55-2505 μg saxitoxin-equivalent/100 g. The two most contaminated samples for PSP toxicity were bivalve Gari solida and carnivorous Argobuccinum ranelliforme with 2505 ± 101 and 1850 ± 137 μg saxitoxin-equivalent/100 g, respectively (p < 0.05). The lipophilic toxins identified were okadaic acid, dinophysistoxin-1 (DTX-1), azaspiracid-1 (AZA-1), pectenotoxin-2 (PTX-2) and yessotoxins (YTX). All analysed molluscs contained lipophilic toxins at levels ranging from 56 ± 4.8 to 156.1 ± 8.2 μg of okadaic acid-equivalent/kg shellfish together with YTX at levels ranging from 1.0 ± 0.1 to 18 ± 0.9 μg of YTX-equivalent/kg shellfish and AZA at levels ranging from 3.6 ± 0.2 to 31 ± 2.1 μg of AZA-equivalent/kg shellfish. Furthermore, different bivalves and gastropods differ in their capacity of retention of lipophilic toxins, as shown by the determination of their respective lipophilic toxins levels. In all the evaluated species, the presence of lipophilic toxins associated with biotransformation in molluscs and carnivorous gastropods was not identified, in contrast to the identification of PSP toxins, where the profiles identified in the different species are directly related to biotransformation processes. Thus, this study provides evidence that the concentration of toxins in the food intake of the evaluated species (Bivalvia and Gastropoda class) determines the degree of

Marine Bacteria with antimicrobials capacity isolated from cultures of bivalve mollusks

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Fabiola Pellon

2014-06-01

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

Preliminary Results on the Evaluation of the Occurrence of Tetrodotoxin Associated to Marine Vibrio spp. in Bivalves from the Galician Rias (Northwest of Spain

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Jose Manuel Leão

2018-03-01

Full Text Available Tetrodotoxins (TTX are a potent group of natural neurotoxins putatively produced by symbiotic microorganisms and affecting the aquatic environment. These neurotoxins have been recently found in some species of bivalves and gastropods along the European Coasts (Greece, UK, and The Netherlands linked to the presence of high concentrations of Vibrio, in particular Vibrio parahaemolyticus. This study is focused on the evaluation of the presence of Vibrio species and TTX in bivalves (mussels, oysters, cockles, clams, scallops, and razor clams from Galician Rias (northwest of Spain. The detection and isolation of the major Vibrio spp. and other enterobacterial populations have been carried out with the aim of screening for the presence of the pathways genes, poliketide synthase (PKS and non-ribosomal peptide synthetase (NRPS possibly involved in the biosynthesis of these toxins. Samples containing Vibrio spp. were analyzed by biochemical (API20E-galery and genetic tests (PCR-RT. These samples were then screened for TTX toxicity by a neuroblastoma cell-based assay (N2a and the presence of TTX was further confirmed by LC-MS/MS. TTX was detected in two infaunal samples. This is the first confirmation of the presence of TTX in bivalve molluscs from the Galician Rias.

Heavy metals in the rock oyster Crassostrea iridescens (Filibranchia: Ostreidae from Mazatlan, Sinaloa, Mexico

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Martín G Frías-Espericueta

1999-12-01

Full Text Available Two populations of Crassostrea iridescens were sampled off Mazatlan and in a zone free of anthropogenic activity. The bivalves were collected from February 1992 to February 1993. Concentrations of Cd, Co, Cr, Cu, Fe, Mn, Ni and Zn were determined by flame atomic absorption spectrophotometry. Annual mean values in the sampling zone off Mazatlan were higher in Co, Cu, Fe, Mn, Ni and Zn than in the sampling zone free of anthropogenic activity; however, differences were not statistically significant at 95% confidence level. Urban discharges in the coastal zone in front of Mazatlan city, have little or no heavy metal concentrations dissolved or particulated.Dos poblaciones de Crassostrea iridescens fueron muestreadas en la zona costera de la ciudad de Mazatlan y en una zona libre de actividad antropogénica. Los bivalvos fueron colectados de febrero de 1992 a febrero de 1993. Concentraciones de Cd, Co, Cr, Cu, Fe, Mn, Ni y Zn fueron determinados por espectrofotometría de absorción atómica. Los valores medios anuales en la estación de muestreo de la ciudad de Mazatlán fueron mayores en Co, Cu, Fe, Mn, Ni y Zn que los determinados en la zona libre de actividad antropogénica; sin embargo, las diferencias no fueron significativas al nivel de confianza del 95%. Una conclusión es que las descargas urbanas en la zona costera en frente de Mazatlán no tiene, o tiene, bajas concentraciones de metales pesados disueltos o particulados.

Hemocyte parameters of the Pacific oyster Crassostrea gigas a year after the Hebei Spirit oil spill off the west coast of Korea

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Donaghy, Ludovic; Hong, Hyun-Ki; Lee, Hee-Jung; Jun, Je-Cheon; Park, Young-Je; Choi, Kwang-Sik

2010-12-01

In marine bivalves, hemocytes support various physiological functions, including immune defense, nutrient transport, shell repair, and homeostatic maintenance. Although the effects of marine contaminants on the immunological functions of bivalves have been extensively investigated, the impacts of oil spills are not well understood. Therefore, we investigated hemocyte parameters in the Pacific oyster Crassostrea gigas 13 months after the Hebei Spirit oil spill (December 2007) off the west coast of Korea. The parameters studied included hemocyte concentration and mortality, relative proportion of hemocyte populations, and immunological functions such as phagocytosis and oxidative activity using flow cytometry. These immune-related parameters in oysters damaged by the oil spill were also compared to control oysters that were collected from an area unaffected by the spill. The flow cytometry study indicated that granulocyte population, phagocytic capacity, and reactive oxygen species production in oysters exposed to crude oil 13 months prior were depressed compared to the unexposed control oysters. Our data suggest that immunocompetence in oysters affected by the oil spill had not fully recovered 1 year after the accident, although more detailed studies on the physiology and disease resistance should be performed.

Evaluation of pollution in Camichin estuary (Mexico): pro-oxidant and antioxidant response in oyster (Crassostrea corteziensis).

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Girón-Pérez, M I; Romero-Bañuelos, C A; Toledo-Ibarra, G A; Rojas-García, A E; Medina-Diaz, I M; Robledo-Marenco, M L; Vega-López, A

2013-08-01

The physiological system of molluscs, particularly pro-oxidant and antioxidant mechanisms, could be altered by pollutants and induce disturbance on health status and productive parameters of aquatic organisms, such as oyster. Therefore, the aim of this study was to evaluate the chemical contamination in water (total metals and polycyclic aromatic hydrocarbons) and oxidative stress parameters in oysters (Crassostrea corteziensis) in Camichin estuary, located in Mexican Tropical Pacific. The results obtained showed the presence of arsenic, lead and zinc, as well as naphthalene, pyrene and benzo[a]pyrene in concentrations relatively higher than criteria established by local and international guidelines. Regarding the biomarkers of oxidative stress response (H2O2 and O2 concentration, catalase activity, lipid peroxidation, and hydroperoxide concentration), differences between oyster from estuary and control group were significant. These results indicate that these pollutants could be related with oxidative stress detected in oyster. Copyright © 2013 Elsevier Inc. All rights reserved.

Occurrence of potentially pathogenic Vibrio in oysters (Crassostrea gigas) and waters from bivalve mollusk cultivations in the South Bay of Santa Catarina.

Science.gov (United States)

Ramos, Roberta Juliano; Miotto, Letícia Adélia; Miotto, Marília; Silveira Junior, Nelson; Cirolini, Andréia; Silva, Helen Silvestre da; Rodrigues, Dália dos Prazeres; Vieira, Cleide Rosana Werneck

2014-01-01

This research aimed to identify and quantify potentially pathogenic Vibrio from different cultivations of bivalve shellfish in the State of Santa Catarina, Brazil, and water regions in the South Bay, as well as correlate the incidence of these microorganisms with the physicochemical parameters of marine waters. Between October 2008 and March 2009, 60 oyster and seawater samples were collected from six regions of bivalve mollusk cultivation, and these samples were submitted for Vibrio counts. Twenty-nine (48.3%) oyster samples were revealed to be contaminated with one or more Vibrio species. The Vibrio parahaemolyticus and Vibrio vulnificus counts in the samples ranged from oyster and from oyster, respectively. Of the 60 seawater samples analyzed, 44 (73.3%) showed signs of contamination with one or more vibrio species. The counts of V. parahaemolyticus and V. vulnificus in the samples ranged from < 0.3 log10 MPN·100mL(-1) to 1.7 log10MPN·100mL(-1) seawater and from < 0.3 log10 MPN·100mL(-1) to 2.0 log10 MPN·100mL(-1) seawater, respectively. A positive correlation between V. vulnificus counts and the seawater temperature as well as a negative correlation between the V. parahaemolyticus counts and salinity were observed. The results suggest the need to implement strategies to prevent vibrio diseases from being transmitted by the consumption of contaminated bivalve shellfish.

First evidence of a potential antibacterial activity involving a laccase-type enzyme of the phenoloxidase system in Pacific oyster Crassostrea gigas haemocytes.

Science.gov (United States)

Luna-Acosta, Andrea; Saulnier, Denis; Pommier, Mylène; Haffner, Philippe; De Decker, Sophie; Renault, Tristan; Thomas-Guyon, Hélène

2011-12-01

Phenoloxidases (POs) are a group of copper proteins including tyrosinase, catecholase and laccase. In several insects and crustaceans, antibacterial substances are produced through the PO cascade, participating in the direct killing of invading microorganisms. However, although POs are widely recognised as an integral part of the invertebrate immune defence system, experimental evidence is lacking that these properties are conserved in molluscs, and more particularly in the Pacific oyster Crassostrea gigas. In the present study, Vibrio splendidus LGP32 and Vibrio aestuarianus 02/041 growths were affected, after being treated with C. gigas haemocyte lysate supernatant (HLS), and either a common substrate of POs, l-3,4-dihydroxyphenylalanine (L-DOPA), to detect catecholase-type PO activity, or a specific substrate of laccase, p-phenylenediamine (PPD), to detect laccase-type PO activity. Interestingly, a higher bacterial growth inhibition was observed in the presence of PPD than in the presence of L-DOPA. These effects were suppressed when the specific PO inhibitor, phenylthiourea (PTU), was added to the medium. Results of the present study suggest, for the first time in a mollusc species, that antibacterial activities of HLS from C. gigas potentially involve POs, and more particularly laccase catalysed reactions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Structure and density population of the invasive mollusc Limnoperna fortunei associated with Eichhornia crassipes in lakes of the Middle Paraná floodplain

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Gabriela E. Musin

2015-04-01

Full Text Available The roots of Eichhornia crassipes provide different microhabitats for invertebrates, including substrate for the Asian invasive bivalve Limnoperna fortunei. This work evaluated the density and size structure of L. fortunei on the roots of E. crassipes in lentic waterbodies associated with the Middle Paraná floodplain. The field work was carried out between November 2009–2010, covering different phases of the hydrological regime. Floating meadows of E. crassipes were sampled monthly in two lakes with different degrees of connection to the main channel of the Paraná River. Bivalve densities were not associated with variations of the biomass of E. crassipes roots and the highest mussel densities were recorded during months of high temperature. The maximum size recorded in both lakes corresponded to individuals approximately 2.5 years old; however, up to 75% of the molluscs were represented by pre-reproductive individuals (up to 6 months old. In these lakes with soft bottom and limited hard substrates, E. crassipes is an important site for the mussel attachment during its early stages of development and could not be the final site of settlement during its lifecycle.

Heavy metal concentrations in marine molluscs from the Moroccan coastal region

Energy Technology Data Exchange (ETDEWEB)

Maanan, Mohamed [Geolittomer, UMR 6554 LETG - CNRS, Universite de Nantes, BP 81227, 44312 Nantes Cedex 3 (France)], E-mail: mohamed.maanan@univ-nantes.fr

2008-05-15

Mussels (Mytilus galloprovincialis), clams (Venerupis decussatus) and oysters (Crassostrea gigas) were sampled seasonally during 2004-2005, from different coastal environments of Morocco in order to measure their accumulated heavy metal concentrations. The concentrations of Hg and Pb were determined by AFS and ICP-MS methods, respectively, whilst the remaining metals (Cd, Cr, Cu, Mn, Zn and Ni) were quantified by AAS. The soft tissue concentrations of the mussels were on average 7.2 mg kg{sup -1} (Cd), 9.6 mg kg{sup -1} (Pb), 0.6 mg kg{sup -1} (Hg), 26.8 mg kg{sup -1} (Cu), 8.8 mg kg{sup -1} (Cr), 292 mg kg{sup -1} (Zn), 20.8 mg kg{sup -1} (Mn) and 32.8 mg kg{sup -1} (Ni). The highest tissue heavy metal concentrations were recorded in the south from the industrial area of Jorf Lasfar. The relationships between metal concentration and season in each species showed very similar annual profiles with a peak observed around spring-summer. Statistical analysis indicated that different species showed different bioaccumulation of metals depending on study site and season. - The accumulated metal concentrations in bivalves from the clean stations may be considered as useful Atlantic coast reference background levels for future comparison.

Carbon and nitrogen elemental and isotopic ratios of filter-feeding bivalves along the French coasts: An assessment of specific, geographic, seasonal and multi-decadal variations.

Science.gov (United States)

Briant, Nicolas; Savoye, Nicolas; Chouvelon, Tiphaine; David, Valérie; Rodriguez, Samuel; Charlier, Karine; Sonke, Jeroen E; Chiffoleau, Jean François; Brach-Papa, Christophe; Knoery, Joël

2018-02-01

Primary consumers play a key role in coastal ecosystems by transferring organic matter from primary producers to predators. Among them, suspension-feeders, like bivalve molluscs are widely used in trophic web studies. The main goal of this study was to investigate variations of C and N elemental and isotopic ratios in common bivalves (M. edulis, M. galloprovincialis, and C. gigas) at large spatial (i.e. among three coastal regions) and different temporal (i.e. from seasonal to multi-decadal) scales in France, in order to identify potential general or specific patterns and speculate on their drivers. The observed spatial variability was related to the trophic status of the coastal regions (oligotrophic Mediterranean Sea versus meso- to eutrophic English Channel and Atlantic ocean), but not to ecosystem typology (estuaries, versus lagoons versus bays versus littoral systems). Furthermore, it highlighted local specificities in terms of the origin of the POM assimilated by bivalves (e.g., mainly continental POM vs. marine phytoplankton vs. microphytobenthic algae). Likewise, seasonal variability was related both to the reproduction cycle for C/N ratios of Mytilus spp. and to changes in trophic resources for δ 13 C of species located close to river mouth. Multi-decadal evolution exhibited shifts and trends for part of the 30-year series with decreases in δ 13 C and δ 15 N. Specifically, shifts appeared in the early 2000's, likely linking bivalve isotopic ratios to a cascade of processes affected by local drivers. Copyright © 2017 Elsevier B.V. All rights reserved.

The nuclear receptor gene family in the Pacific oyster, Crassostrea gigas, contains a novel subfamily group.

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Vogeler, Susanne; Galloway, Tamara S; Lyons, Brett P; Bean, Tim P

2014-05-15

Nuclear receptors are a superfamily of transcription factors important in key biological, developmental and reproductive processes. Several of these receptors are ligand- activated and through their ability to bind endogenous and exogenous ligands, are potentially vulnerable to xenobiotics. Molluscs are key ecological species in defining aquatic and terrestrial habitats and are sensitive to xenobiotic compounds in the environment. However, the understanding of nuclear receptor presence, function and xenobiotic disruption in the phylum Mollusca is limited. Here, forty-three nuclear receptor sequences were mined from the genome of the Pacific oyster, Crassostrea gigas. They include members of NR0-NR5 subfamilies, notably lacking any NR6 members. Phylogenetic analyses of the oyster nuclear receptors have been conducted showing the presence of a large novel subfamily group not previously reported, which is named NR1P. Homologues to all previous identified nuclear receptors in other mollusc species have also been determined including the putative heterodimer partner retinoid X receptor, estrogen receptor and estrogen related receptor. C. gigas contains a highly diverse set of nuclear receptors including a novel NR1 group, which provides important information on presence and evolution of this transcription factor superfamily in invertebrates. The Pacific oyster possesses two members of NR3, the sex steroid hormone receptor analogues, of which there are 9 in humans. This provides increasing evidence that steroid ligand specific expansion of this family is deuterostome specific. This new knowledge on divergence and emergence of nuclear receptors in C. gigas provides essential information for studying regulation of molluscan gene expression and the potential effects of xenobiotics.

Analysis of the scallop microbiota by means of 16S rRNA gene pyrosequencing

OpenAIRE

Alex Mira; Jesus L Romalde

2014-01-01

Bivalve molluscs, due to its filter-feeding mechanism, have an abundant associated bacterial microbiota composed of a large number of species of different genera. The knowledge about the composition of the microbiota associated with bivalve molluscs is based, mostly, on techniques of cultivation of microorganisms, but also on DGGE methods. However, it is estimated that less than 1% of the bacteria are culturable with current methods, which lead to an underestimation of the microbial diversity...

Příspěvek k poznání vodních měkkýšů evropsky významné lokality Bystřice se zaměřením na populaci velevruba tupého (Unio crassus A contribution to the knowledge of aquatic molluscs of the Bystřice SCI focused on the population of Unio crassus

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Luboš Beran

2011-03-01

Full Text Available This paper brings results of a malacological survey of the Bystřice River on the territory of the Site of Community Importance (SCI Bystřice (Eastern Bohemia, Czech Republic. The research was focused on the population of endangered bivalve Unio crassus which is the main object of conservation of this SCI. Twenty one species of aquatic molluscs (11 gastropods, 10 bivalves were found in 2010. Most of the molluscs belong to common and widespread species. Altogether 26 species have been found during research in the Bystřice River since 2000. Expansion of non-native species Potamopyrgus antipodarum and Physella acuta is the most visible change in comparison with the previous research. The research in 2010 confirmed existence of the occurrence of Unio crassus all over the SCI and also upstream of this site. The population density documented in 2010 was higher than that found during the previous research. In the upper part of the SCI, the density of U. crassus population was at least 1 ind./1 m of the river stream while in the lower part it did not exceed 1 ind. per 10 m of the river. The reason was the canalisation of the river and the absence of suitable sediments. The occurrence of the bivalve was not recorded downstream of the SCI.

Identification and Functional Characterization of the Glycogen Synthesis Related Gene Glycogenin in Pacific Oysters (Crassostrea gigas).

Science.gov (United States)

Li, Busu; Meng, Jie; Li, Li; Liu, Sheng; Wang, Ting; Zhang, Guofan

2017-09-06

High glycogen levels in the Pacific oyster (Crassostrea gigas) contribute to its flavor, quality, and hardiness. Glycogenin (CgGN) is the priming glucosyltransferase that initiates glycogen biosynthesis. We characterized the full sequence and function of C. gigas CgGN. Three CgGN isoforms (CgGN-α, β, and γ) containing alternative exon regions were isolated. CgGN expression varied seasonally in the adductor muscle and gonadal area and was the highest in the adductor muscle. Autoglycosylation of CgGN can interact with glycogen synthase (CgGS) to complete glycogen synthesis. Subcellular localization analysis showed that CgGN isoforms and CgGS were located in the cytoplasm. Additionally, a site-directed mutagenesis experiment revealed that the Tyr200Phe and Tyr202Phe mutations could affect CgGN autoglycosylation. This is the first study of glycogenin function in marine bivalves. These findings will improve our understanding of glycogen synthesis and accumulation mechanisms in mollusks. The data are potentially useful for breeding high-glycogen oysters.

Molluscs of an intertidal soft-sediment area in China: Does overfishing explain a high density but low diversity community that benefits staging shorebirds?

Science.gov (United States)

Yang, Hong-Yan; Chen, Bing; Piersma, Theunis; Zhang, Zhengwang; Ding, Changqing

2016-03-01

The Yellow Sea is a key staging ground for shorebirds that migrate from Australasia to the Arctic each spring. A lot of attention has been paid to the impact of habitat loss due to land reclamation on shorebird survival, but any effects of overfishing of coastal resources are unclear. In this study, the abundance of molluscs in the intertidal mudflats of northern Bohai Bay on the Chinese Yellow Sea was investigated in 2008-2014 from the perspective of their importance as food for northward migrating shorebirds, especially Red Knots Calidris canutus. Numerically contributing 96% to the numbers of 17 species found in spring 2008, the bivalve Potamocorbula laevis (the staple food of Red Knots and other shorebirds) dominated the intertidal mollusc community. In the spring of 2008-2014, the densities of P. laevis were surprisingly high, varying between 3900 and 41,000 individuals/m2 at distinctly small sizes (average shell lengths of 1.1 to 4.8 mm), and thus reaching some of the highest densities of marine bivalves recorded worldwide and providing good food for shorebirds. The distribution of P. laevis was associated with relatively soft sediments in close proximity to the recently built seawalls. A monthly sampling programme showed steep seasonal changes in abundance and size. P. laevis were nearly absent in winter, each year settling on the intertidal mudflats anew. Peak densities were reached in spring, when 0-age P. laevis were 1-3 mm long. The findings point to a highly unusual demographic structure of the species, suggesting that some interfering factors are at play. We hypothesise that the current dominance of young P. laevis in Bohai Bay reflects the combined pressures of a nearly complete active removal of adult populations from mid-summer to autumn for shrimp farming (this clearing of adults may offer space for recruitment during the next spring) and low numbers of epibenthic predators of bivalves, such as shrimps and crabs, due to persistent overfishing in

Evaluation of yolk protein as biomarkers for endocrine disruption in molluscs

DEFF Research Database (Denmark)

Morthorst, Jane Ebsen; Holbech, Henrik; Kinnberg, Karin Lund

is also regulated by estrogens in molluscs even though it still remains unknown if and where vertebrate steroids are synthesized in molluscs and regulation of the endocrine system in molluscs is also unknown. By using our newly developed ELISA the present work investigates if yolk protein is a suitable......During recent years invertebrates and especially molluscs have received increasing attention in the field of endocrine disruption and development of OECD test guidelines to assess the effects of endocrine disrupting compounds (EDCs) in molluscs is under development. The development of standardized...... tests to detect effects of EDCs in molluscs has proved cumbersome due to lack of specific biomarkers and endpoints for endocrine effects. Intersex (presence of oocytes in the testis) and induction of vitellogenin (the yolk protein precursor in oviparous vertebrates) have been used as biomarkers for EDCs...

Microplastics in commercial bivalves from China

International Nuclear Information System (INIS)

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

2015-01-01

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. - Highlights: • Fiber, fragment and pellet microplastics were found in 9 bivalves. • The abundance of microplastics was 2.1–10.5 items/g. • Fibers were the most common microplastics. • The most common size class of microplastics was less than 250 μm. • Microplastic pollution was widespread and serious in commercial bivalves. - Fiber, fragment and pellet microplastics in the range of 2.1–10.5 items/g were observed in 9 species of commercially popular bivalves from China.

Temperature-dependent stress response in oysters, Crassostrea virginica: Pollution reduces temperature tolerance in oysters

International Nuclear Information System (INIS)

Lannig, Gisela; Flores, Jason F.; Sokolova, Inna M.

2006-01-01

Combined effects of temperature and a toxic metal, cadmium (Cd), on energy metabolism were studied in a model marine bivalve, the eastern oyster Crassostrea virginica, acclimated at 20, 24 and 28 deg. C and exposed to 50 μg l -1 of Cd. Both increasing temperature and Cd exposure led to a rise in standard metabolic rates, and combined stressors appeared to override the capability for aerobic energy production resulting in impaired stress tolerance. Oysters exposed to elevated temperature but not Cd showed no significant change in condition, survival rate and lipid peroxidation, whereas those exposed to both Cd and temperature stress suffered high mortality accompanied by low condition index and elevated lipid peroxidation. Furthermore, RNA/DNA ratios indicative of protein synthesis rate, and levels of glutathione, which is involved in metal detoxification, increased in Cd-exposed oysters at 20 deg. C but not at 28 deg. C. Implications of the synergism between elevated temperatures and cadmium stress on energy metabolism of oysters are discussed in the light of the potential effects of climate change on oyster populations in polluted areas

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

Occurrence of potentially pathogenic Vibrio in oysters (Crassostrea gigas and waters from bivalve mollusk cultivations in the South Bay of Santa Catarina

Directory of Open Access Journals (Sweden)

Roberta Juliano Ramos

2014-06-01

Full Text Available Introduction This research aimed to identify and quantify potentially pathogenic Vibrio from different cultivations of bivalve shellfish in the State of Santa Catarina, Brazil, and water regions in the South Bay, as well as correlate the incidence of these microorganisms with the physicochemical parameters of marine waters. Methods Between October 2008 and March 2009, 60 oyster and seawater samples were collected from six regions of bivalve mollusk cultivation, and these samples were submitted for Vibrio counts. Results Twenty-nine (48.3% oyster samples were revealed to be contaminated with one or more Vibrio species. The Vibrio parahaemolyticus and Vibrio vulnificus counts in the samples ranged from < 0.5 log10 Most Probable Number (MPN g–1 to 2.3 log10 MPN g–1 oyster and from < 0.5 log10 MPN g–1 to 2.1 log10 MPN g–1 oyster, respectively. Of the 60 seawater samples analyzed, 44 (73.3% showed signs of contamination with one or more vibrio species. The counts of V. parahaemolyticus and V. vulnificus in the samples ranged from < 0.3 log10 MPN·100mL–1 to 1.7 log10MPN·100mL–1 seawater and from < 0.3 log10 MPN·100mL–1 to 2.0 log10 MPN·100mL–1 seawater, respectively. A positive correlation between V. vulnificus counts and the seawater temperature as well as a negative correlation between the V. parahaemolyticus counts and salinity were observed. Conclusions The results suggest the need to implement strategies to prevent vibrio diseases from being transmitted by the consumption of contaminated bivalve shellfish.

Sensitization pattern of crustacean-allergic individuals can indicate allergy to molluscs

DEFF Research Database (Denmark)

Vidal, C; Bartolomé, B; Rodríguez, V

2015-01-01

This study investigated the sensitization pattern of crustacean-allergic patients according to tolerance to molluscs. Thirty-one patients with anaphylaxis to crustaceans (14 with mollusc allergy and 17 with mollusc tolerance) were studied using skin prick tests (SPTs), specific IgEs (sIgEs) and SDS-PAGE...

Assessment of arsenic in coastal sediments, seawaters and molluscs in the Tarut Island, Arabian Gulf, Saudi Arabia

Science.gov (United States)

El-Sorogy, Abdelbaset S.; Youssef, Mohamed; Al-Kahtany, Khaled; Al-Otaiby, Naif

2016-01-01

In order to assess arsenic on the Tarut coast, Saudi Arabian Gulf, 38 sediment samples, 26 seawater samples and 40 gastropod and bivalve specimens were collected for analyses by Inductively Coupled Plasma-Mass Spectrometer. The Enrichment Factor (EF), the Geoaccumulation Index (Igeo) and the Contamination Factor (CF) indicated that coastal sediments of Tarut Island are severely enriched, strongly polluted and very highly contaminated with arsenic as a result of anthropogenic inputs. Comparison with arsenic in coastal sediments, seawaters and molluscs in the Red Sea, the Arabian Gulf and abroad coasts suggested that the studied samples have higher concentrations of As. The suggested natural sources of arsenic in the study area are the weathering and decomposition of neighboring deserts. The anthropogenic sources include the land reclamation, petrochemical industries, boat exhaust emissions, oil leakage, desalination plants and sewage effluents. These anthropogenic sources are the dominant sources of As in the study area and mostly came from Al Jubail industrial city to the north.

Plio-Pleistocene extinctions and immigration credit reflected in the size-frequency distribution of Mediterranean marine bivalves

Science.gov (United States)

Nawrot, Rafal; Zuschin, Martin; Chattopadhyay, Devapriya

2015-04-01

Following the opening of the Suez Canal hundreds of Red Sea species have entered the Mediterranean Sea making it a global hot spot of marine bioinvasion. With the ongoing influx of the subtropical and tropical alien species and increasing sea surface temperatures, the Mediterranean biota is currently gaining a more tropical character and increasingly becoming a mixture of faunal stocks with different evolutionary histories. This susceptibility to invasion was suggested to reflect the presence of an empty ecological space left after decimation of incumbent warm-water fauna during Plio-Pleistocene climate fluctuations. As molluscs are among the most prolific immigrants, we test this hypothesis using data on taxonomic composition and body size of Pliocene Mediterranean bivalves derived from the literature sources and museum collections. The Pliocene inter-specific size-frequency distribution (SFD) is strikingly similar to the SFDs of the Recent Red Sea bivalve fauna, in spite of different biogeographic provenance and the absence of true reef ecosystems in the Pliocene of the Mediterranean region. In contrast, body-size patterns in both assemblages are significantly different from the present-day Mediterranean fauna characterized by smaller median and modal size. Our preliminary results suggest that the distinct shape of the modern Mediterranean SFD may reflect the selective nature of the late Piacenzian - Galesian (Late Pliocene - Early Pleistocene) extinctions pulses related to the onset of the Northern Hemisphere glaciations. These extinctions affected almost 40% of Pliocene species and were biased towards large-bodied taxa. They were not followed by re-immigration of warm-water species owing to the isolation from the tropical Atlantic biota by the cold upwelling along the NW coasts of Africa. The resulting invasion credit (sensu Jackson & Sax, 2010) is currently being paid by the Red Sea bivalves colonizing the Mediterranean Sea through the Suez Canal. Successful

Molecular identification, phylogeny and geographic distribution of Brazilian mangrove oysters (Crassostrea

Directory of Open Access Journals (Sweden)

Aline Grasielle Costa de Melo

2010-01-01

Full Text Available Oysters (Ostreidae manifest a high degree of phenotypic plasticity, whereby morphology is of limited value for species identification and taxonomy. By using molecular data, the aim was to genetically characterize the species of Crassostrea occurring along the Brazilian coast, and phylogenetically relate these to other Crassostrea from different parts of the world. Sequencing of the partial cytochrome oxidase c subunit I gene (COI, revealed a total of three species of Crassostrea at 16 locations along the Brazilian coast. C. gasar was found from Curuçá (Pará state to Santos (São Paulo state, and C. rhizophorae from Fortim (Ceará state to Florianópolis (Santa Catarina state, although small individuals of the latter species were also found at Ajuruteua beach (municipality of Bragança, Pará state. An unidentified Crassostrea species was found only on Canela Island, Bragança. Crassostrea gasar and C. rhizophorae grouped with C. virginica, thereby forming a monophyletic Atlantic group, whereas Crassostrea sp. from Canela Island was shown to be more similar to Indo-Pacific oysters, and either arrived in the Atlantic Ocean before the convergence of the Isthmus of Panama or was accidentally brought to Brazil by ship.

Molecular identification, phylogeny and geographic distribution of Brazilian mangrove oysters (Crassostrea)

Science.gov (United States)

2010-01-01

Oysters (Ostreidae) manifest a high degree of phenotypic plasticity, whereby morphology is of limited value for species identification and taxonomy. By using molecular data, the aim was to genetically characterize the species of Crassostrea occurring along the Brazilian coast, and phylogenetically relate these to other Crassostrea from different parts of the world. Sequencing of the partial cytochrome oxidase c subunit I gene (COI), revealed a total of three species of Crassostrea at 16 locations along the Brazilian coast. C. gasar was found from Curuçá (Pará state) to Santos (São Paulo state), and C. rhizophorae from Fortim (Ceará state) to Florianópolis (Santa Catarina state), although small individuals of the latter species were also found at Ajuruteua beach (municipality of Bragança, Pará state). An unidentified Crassostrea species was found only on Canela Island, Bragança. Crassostrea gasar and C. rhizophorae grouped with C. virginica, thereby forming a monophyletic Atlantic group, whereas Crassostrea sp. from Canela Island was shown to be more similar to Indo-Pacific oysters, and either arrived in the Atlantic Ocean before the convergence of the Isthmus of Panama or was accidentally brought to Brazil by ship. PMID:21637433

Trojan Horse Strategy for Non-invasive Interference of Clock Gene in the Oyster Crassostrea gigas.

Science.gov (United States)

Payton, Laura; Perrigault, Mickael; Bourdineaud, Jean-Paul; Marcel, Anjara; Massabuau, Jean-Charles; Tran, Damien

2017-08-01

RNA interference is a powerful method to inhibit specific gene expression. Recently, silencing target genes by feeding has been successfully carried out in nematodes, insects, and small aquatic organisms. A non-invasive feeding-based RNA interference is reported here for the first time in a mollusk bivalve, the pacific oyster Crassostrea gigas. In this Trojan horse strategy, the unicellular alga Heterocapsa triquetra is the food supply used as a vector to feed oysters with Escherichia coli strain HT115 engineered to express the double-stranded RNA targeting gene. To test the efficacy of the method, the Clock gene, a central gene of the circadian clock, was targeted for knockout. Results demonstrated specific and systemic efficiency of the Trojan horse strategy in reducing Clock mRNA abundance. Consequences of Clock disruption were observed in Clock-related genes (Bmal, Tim1, Per, Cry1, Cry2, Rev.-erb, and Ror) and triploid oysters were more sensitive than diploid to the interference. This non-invasive approach shows an involvement of the circadian clock in oyster bioaccumulation of toxins produced by the harmful alga Alexandrium minutum.

First isolation of Nocardia crassostreae from Pacific oysters (Crassostrea gigas) in Europe

NARCIS (Netherlands)

Engelsma, M.Y.; Roozenburg, I.; Joly, J.P.

2008-01-01

In summer 2006 an extensive mortality of Pacific oysters Crassostrea gigas occurred in Lake Grevelingen, the Netherlands. A sample of Pacific oysters was investigated for the presence of shellfish pathogens as potential causes of the mortality. Yellow-green lesions were observed in several oysters

Factors influencing the microplastic contamination of bivalves from the French Atlantic coast: Location, season and/or mode of life?

Science.gov (United States)

Phuong, Nam Ngoc; Poirier, Laurence; Pham, Quoc Tuan; Lagarde, Fabienne; Zalouk-Vergnoux, Aurore

2018-04-01

Monitoring the presence of microplastics (MP) in marine organisms is currently of high importance. This paper presents the qualitative and quantitative MP contamination of two bivalves from the French Atlantic coasts: the blue mussel (Mytilus edulis) and the Pacific oyster (Crassostrea gigas). Three factors potentially influencing the contamination were investigated by collecting at different sampling sites and different seasons, organisms both wild and cultivated. Inter- and intra-species comparisons were also achieved. MP quantity in organisms was evaluated at 0.61±0.56 and 2.1±1.7MP per individual respectively for mussels and oysters. Eight different polymers were identified. Most of the MPs were fragments; about a half of MPs were grey colored and a half with a size ranging from 50 to 100μm for both studied species. Some inter-specific differences were found but no evidence for sampling site, season or mode of life effect was highlighted. Copyright © 2017 Elsevier Ltd. All rights reserved.

Changes in the composition and diversity of the bacterial microbiota associated with oysters (Crassostrea corteziensis, Crassostrea gigas and Crassostrea sikamea) during commercial production.

Science.gov (United States)

Trabal Fernández, Natalia; Mazón-Suástegui, José M; Vázquez-Juárez, Ricardo; Ascencio-Valle, Felipe; Romero, Jaime

2014-04-01

The resident microbiota of three oyster species (Crassostrea corteziensis, Crassostrea gigas and Crassostrea sikamea) was characterised using a high-throughput sequencing approach (pyrosequencing) that was based on the V3-V5 regions of the 16S rRNA gene. We analysed the changes in the bacterial community beginning with the postlarvae produced in a hatchery, which were later planted at two grow-out cultivation sites until they reached the adult stage. DNA samples from the oysters were amplified, and 31 008 sequences belonging to 13 phyla (including Proteobacteria, Bacteroidetes, Actinobacteria and Firmicutes) and 243 genera were generated. Considering all life stages, Proteobacteria was the most abundant phylum, but it showed variations at the genus level between the postlarvae and the adult oysters. Bacteroidetes was the second most common phylum, but it was found in higher abundance in the postlarvae than in adults. The relative abundance showed that the microbiota that was associated with the postlarvae and adults differed substantially, and higher diversity and richness were evident in the postlarvae in comparison with adults of the same species. The site of rearing influenced the bacterial community composition of C. corteziensis and C. sikamea adults. The bacterial groups that were found in these oysters were complex and metabolically versatile, making it difficult to understand the host-bacteria symbiotic relationships; therefore, the physiological and ecological significances of the resident microbiota remain uncertain. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Ecological drivers and habitat associations of estuarine bivalves

Directory of Open Access Journals (Sweden)

C. Seabird McKeon

2015-11-01

Full Text Available Community composition of the infaunal bivalve fauna of the St. Lucie Estuary and southern Indian River Lagoon, eastern Florida was sampled quarterly for 10 years as part of a long-term benthic monitoring program. A total of 38,514 bivalves of 137 taxa were collected and identified. We utilized this data, along with sediment samples and environmental measurements gathered concurrently, to assess the community composition, distribution, and ecological drivers of the infaunal bivalves of this estuary system. Salinity had the strongest influence on bivalve assemblage across the 15 sites, superseding the influences of sediment type, water turbidity, temperature and other environmental parameters. The greatest diversity was found in higher salinity euhaline sites, while the greatest abundance of individual bivalves was found in medium salinity mixohaline sites, the lowest diversity and abundances were found in the low salinity oligohaline sites, demonstrating a strong positive association between salinity and diversity/abundance. Water management decisions for the estuary should incorporate understanding of the role of salinity on bivalve diversity, abundance, and ecosystem function.

Ecological drivers and habitat associations of estuarine bivalves.

Science.gov (United States)

McKeon, C Seabird; Tunberg, Björn G; Johnston, Cora A; Barshis, Daniel J

2015-01-01

Community composition of the infaunal bivalve fauna of the St. Lucie Estuary and southern Indian River Lagoon, eastern Florida was sampled quarterly for 10 years as part of a long-term benthic monitoring program. A total of 38,514 bivalves of 137 taxa were collected and identified. We utilized this data, along with sediment samples and environmental measurements gathered concurrently, to assess the community composition, distribution, and ecological drivers of the infaunal bivalves of this estuary system. Salinity had the strongest influence on bivalve assemblage across the 15 sites, superseding the influences of sediment type, water turbidity, temperature and other environmental parameters. The greatest diversity was found in higher salinity euhaline sites, while the greatest abundance of individual bivalves was found in medium salinity mixohaline sites, the lowest diversity and abundances were found in the low salinity oligohaline sites, demonstrating a strong positive association between salinity and diversity/abundance. Water management decisions for the estuary should incorporate understanding of the role of salinity on bivalve diversity, abundance, and ecosystem function.

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sub-chronic exposure to fluoxetine in juvenile oysters (Crassostrea gigas): uptake and biological effects.

Science.gov (United States)

Di Poi, Carole; Evariste, Lauris; Séguin, Alexis; Mottier, Antoine; Pedelucq, Julie; Lebel, Jean-Marc; Serpentini, Antoine; Budzinski, Hélène; Costil, Katherine

2016-03-01

The bioconcentration potential of fluoxetine (FLX) and its biological effects were investigated in juvenile Pacific oyster exposed for 28 days to environmentally relevant concentrations of FLX (1 ng L(-1), 100 ng L(-1) and up to 10 μg L(-1)). FLX bioaccumulated in oyster flesh resulting in 28-day bioconcentration factors greater than 2,000 and 10,000 by referring to wet and dry weights, respectively. Nevertheless, FLX did not induce oyster mortality, delayed gametogenesis, or lead to adverse histopathological alterations. At the two highest concentrations, despite non-optimal trophic conditions, FLX stimulated shell growth but only in a transient manner, suggesting a role of serotonin in the regulation of feeding and metabolism in bivalves. Those high concentrations seemed to drive bell-shaped responses of catalase and glutathione S-transferase activities throughout the exposure period, which may indicate the activation of antioxidant enzyme synthesis and then an enhanced catabolic rate or direct inhibition of those enzymes. However, no clear oxidative stress was detected because no strong differences in thiobarbituric acid-reactive substance (TBARS) content (i.e. lipid peroxidation) were observed between oyster groups, suggesting that cellular defence mechanisms were effective. These results demonstrate the importance of considering additional biomarkers of oxidative stress to obtain a comprehensive overview of the FLX-induced changes in marine bivalves exposed under realistic conditions. Considering the battery of biomarkers used, FLX appears to induce little or no effects on oyster physiology even at a concentration of 10 μg L(-1). These results do not confirm the lowest observed effect concentration (LOEC) values reported by some authors in other mollusc species.

Development and validation of OECD test guidelines on mollusc reproductive toxicity tests

DEFF Research Database (Denmark)

Lagadic, Laurent; Holbech, Henrik; hutchinson, tom

the comparison of endpoints relevant for reproduction in invertebrates often shows a much higher sensitivity in molluscs vs. e.g. daphnids. The OECD test guideline programme has thus been extended to cover reproduction effects of chemicals in molluscs. Existing mollusc toxicity test protocols have been reviewed...... in an OECD Detailed Review Paper that identifies two relevant candidate species for developing freshwater tests: Potamopyrgus antipodarum and Lymnaea stagnalis. However, this review did not clarify which toxicity test design/conditions are the most appropriate for chemicals assessment. Therefore, a mollusc...... reproduction test guideline will be developed describing partial- and full- life-cycle test protocols in these species, so as to propose a balanced suite of apical mollusc toxicity tests applicable for the assessment of any type of chemical, including endocrine disruptors, as level 4 and 5 assays of the EDTA...

D1 dopamine receptor is involved in shell formation in larvae of Pacific oyster Crassostrea gigas.

Science.gov (United States)

Liu, Zhaoqun; Wang, Lingling; Yan, Yunchen; Zheng, Yan; Ge, Wenjing; Li, Meijia; Wang, Weilin; Song, Xiaorui; Song, Linsheng

2018-07-01

Dopamine (DA), a significant member of catecholamines, is reported to induce biomineralization of calcium carbonate vaterite microspheres via dopamine receptor (DR) in bivalves, implying the modulation of dopaminergic system on shell formation during larval development. In this research, a homologue of D1 type DR (CgD1DR-1) was identified from oyster Crassostrea gigas, whose full length cDNA was 1197 bp. It was widely expressed in various tissues of C. gigas, with the significantly higher levels in hepatopancreas, mantle, muscle and gill. During developmental stages, the mRNA transcripts of CgD1DR-1 in D-shape larvae were obviously higher (p < 0.05) than those in trochophore and umbo larvae, and CO 2 exposure could inhibit the synthesis of DA and mRNA expression of CgD1DR-1. After cell transfection and DA treatment, intracellular cAMP in cells with the expression of CgD1DR-1 increased significantly (p < 0.05). Furthermore, the incubation with SCH 23390 for the blockage of CgD1DR-1 significantly restrained the expressions of six shell formation-related genes including CgTyrosinase-1, CgTyrosinase-3, CgChitinaseLP, CgAMC, CgBMP and CgBMPR in trochophore and D-shape larvae. These results jointly suggested that DA together with its receptor CgD1DR-1 might be involved in shell formation during oyster larval development from trochophore to D-shape larvae, and CO 2 -induced ocean acidification (OA) might influence marine bivalves by inhibiting the DA-D1DR pathway to prohibit their shell formation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Transcriptome of the Antarctic brooding gastropod mollusc Margarella antarctica.

Science.gov (United States)

Clark, Melody S; Thorne, Michael A S

2015-12-01

454 RNA-Seq transcriptome data were generated from foot tissue of the Antarctic brooding gastropod mollusc Margarella antarctica. A total of 6195 contigs were assembled de novo, providing a useful resource for researchers with an interest in Antarctic marine species, phylogenetics and mollusc biology, especially shell production. Copyright © 2015 Elsevier B.V. All rights reserved.

Neuro-endocrine disruption in molluscs

DEFF Research Database (Denmark)

Holbech, Henrik; Bech Sanderhoff, Lene; Waller, Stine P.

The Mollusca phylum is the second largest animal phylum with around 85,000 registered mollusc species and increasing attention to effects of chemicals on the molluscan endocrine system have been given during the last years. This includes initiation of the development of OECD test guidelines (TG...... efficient and fast in vivo system using embryos of the freshwater pulmonate gastropod Lymnaea stagnalis (the great pond snail). It is known that serotonin and dopamine are involved in many reproductive processes in molluscs Incl. egg maturation and spawning and that pedal ciliary activity causing L....... stagnalis embryos to rotate in the eggs is serotonin/dopamine regulated. We have developed a system to quantify embryo rotation and present results of exposure to serotonin, dopamine and different anti-depressive pharmaceuticals (e.g. selective serotonin reuptake inhibitors, SSRI´s) using the L. stagnalis...

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

Ecological drivers and habitat associations of estuarine bivalves

OpenAIRE

McKeon, C. Seabird; Tunberg, Bj?rn G.; Johnston, Cora A.; Barshis, Daniel J.

2015-01-01

Community composition of the infaunal bivalve fauna of the St. Lucie Estuary and southern Indian River Lagoon, eastern Florida was sampled quarterly for 10 years as part of a long-term benthic monitoring program. A total of 38,514 bivalves of 137 taxa were collected and identified. We utilized this data, along with sediment samples and environmental measurements gathered concurrently, to assess the community composition, distribution, and ecological drivers of the infaunal bivalves of this es...

Investigation and measurement of radio thermoluminescence properties of some calci tic mollusc shells of the Persian Gulf and the Oman Sea (for γ radiation dosimetry)

International Nuclear Information System (INIS)

Ghafourian, H.; Rabbani, M.; Rouhi, U.

2000-01-01

Biogenic Calcium Carbonate, particularly as naturally thermoluminescent calci tic mollusc shells may serve as excellent radio thermoluminescent dosimeters. In this study the radio thermoluminescence properties of 8 different bivalves of the Persian Gulf, the Oman Sea and the internal calcite shell of Sepia sp. are investigated. The results of this investigation have shown that the shells of Sepia sp., Pinctata radiata and Card ita bicolor as appropriate dosimeters for both personal and industrial dosimetry purposes, among which Sepia sp. is the most sensitive one. Callista umbonella and Mactra sp. are relatively less thermoluminescent while Saccostrea Cucullata and Chlamys ruschenbergerii are completely inert with respect to γ - thermoluminescence. Thermoluminescence properties of Anadara refescens and Anadara secticostata decrease surprisingly by an increase in the absorbed dose of γ radiation, which can mainly be interpreted as the result of crystal lattice destruction caused by ionizing radiation

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.

Immunotoxicological effects of environmental contaminants on marine bivalves.

Science.gov (United States)

Renault, T

2015-09-01

Coastal areas are complex environments frequently contaminated by numerous pollutants that represent a potential threat to marine organisms, especially bivalves. These pollutants may have major ecological consequences. Although effects of different environmental contaminants on the immune system in marine bivalves have been already reported, a few of reviews summarizes these effects. The main purpose of this chapter relies on summarizing recent body of data on immunotoxicity in bivalves subjected to contaminants. Immune effects of heavy metals, pesticides, HAP, PCB and pharmaceuticals are presented and discussed and a particular section is devoted to nanoparticle effects. A large body of literature is now available on this topic. Finally, the urgent need of a better understanding of complex interactions between contaminants, marine bivalves and infectious diseases is noticed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Příspěvek k poznání vodních měkkýšů severní části CHKO Orlické hory

Directory of Open Access Journals (Sweden)

Luboš Beran

2009-03-01

Full Text Available This paper brings a review of a malacological survey of the northern part of the Orlické Hory Protected Landscape Area, situated in northwestern part of Bohemia (Czech Republic near boundary between the Czech Republic and Poland. Altogether, only 12 common species of aquatic molluscs (8 gastropods, 4 bivalves were found. Galba truncatula, Radix peregra, Ancylus fluviatilis, Pisidium personatum, and P. casertanum belong to the most frequent molluscs found during this research. Occurrence of vulnerable or endangered molluscs as well as non-native molluscs was not documented in this area.

Laboratory investigations of the effects of predator sex and size on prey selection by the Asian crab, Hemigrapsus sanguineus.

Science.gov (United States)

Brousseau, D J.; Filipowicz, A; Baglivo, J A.

2001-07-30

Laboratory studies have shown that the nonindigenous Asian shore crab, Hemigrapsus sanguineus, readily consumes three species of commercial bivalves: blue mussels, Mytilus edulis, soft-shell clams, Mya arenaria, and oysters, Crassostrea virginica. Although crabs can eat bivalves of a wide size range, they preferred the smaller prey (Hemigrapsus that occur in the wild, their effectiveness as predators of juvenile bivalves and their large appetites suggest an important role for these predators in restructuring the prey communities in habitats into which they have been introduced.

Mollusc reproductive toxicity tests - Development and validation of test guidelines

DEFF Research Database (Denmark)

Ducrot, Virginie; Holbech, Henrik; Kinnberg, Karin Lund

. Draft standard operating procedures (SOPs) have been designed based upon literature and expert knowledge from project partners. Pre-validation studies have been implemented to validate the proposed test conditions and identify issues in performing the SOPs and analyzing test results. Pre-validation work......The Organisation for Economic Cooperation and Development is promoting the development and validation of mollusc toxicity tests within its test guidelines programme, eventually aiming for the standardization of mollusc apical toxicity tests. Through collaborative work between academia, industry...... and stakeholders, this study aims to develop innovative partial life-cycle tests on the reproduction of the freshwater gastropods Potamopyrgus antipodarum and Lymnaea stagnalis, which are relevant candidate species for the standardization of mollusc apical toxicity tests assessing reprotoxic effects of chemicals...

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

Fossils mollusc asemblage found at Zagarzazu, marine Pleistocene, Uruguay

International Nuclear Information System (INIS)

Rojas, A. . E mail: alejandra@fcien.edu.uy

2004-01-01

There are presented the results of the paleoecological analysis of the mollusc assemblage found at Zagarzazu, Colonia department. The fossils are well preserved, arranged in thin shell-beds with some specimens in life position. The assemblage is indicative of higher temperatures than present, and a strong marine influence. It is important to stress that new thermophilic molluscs for the marine Quaternary were found and that this locality represents a new Pleistocene marine record in Uruguay [es

Concentration of PSP (Paralytic Shellfish Poisoning) Toxin On Shellfish From Inner Ambon Bay and Kao Bay North Halmahera

Science.gov (United States)

Pello, F. S.; Haumahu, S.; Huliselan, N. V.; Tuapattinaja, M. A.

2017-10-01

The Inner Ambon Bay and Kao Bay have potential on fisheries resources which one of them is molluscs. Molluscs especially for class bivalve have economical values and are consumed by coastal community. The research had been done to analyze saxitoxin (STX) concentration on bivalves from Kao Bay and Inner Ambon Bay. The Saxitoxin Elisa Test Kit Protocol was used to determine saxitoxin concentration. The measurement showed that the highest concentration of saxitoxin (392.42 µg STXeq/100g shellfish meat) was Gafrarium tumidum from Ambon Bay, whereas concentration of saxitoxin (321.83 µg STXeq/100g shellfish meat) was Mactra mera from Kao Bay

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

Source and impact of lead contamination on δ-aminolevulinic acid dehydratase activity in several marine bivalve species along the Gulf of Cadiz

International Nuclear Information System (INIS)

Company, R.; Serafim, A.; Lopes, B.; Cravo, A.; Kalman, J.; Riba, I.; DelValls, T.A.; Blasco, J.; Delgado, J.; Sarmiento, A.M.; Nieto, J.M.; Shepherd, T.J.; Nowell, G.; Bebianno, M.J.

2011-01-01

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 (δ-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 ( 206 Pb/ 204 Pb, 207 Pb/ 204 Pb and 208 Pb/ 204 Pb) were determined in the whole soft tissues. The highest Pb concentrations were determined in S. plana (3.50 ± 1.09 μg g -1 Pb d.w.) and D. trunculus (1.95 ± 0.10 μg g -1 Pb d.w.), while M. galloprovincialis and C. angulata showed the lowest Pb levels ( -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 -8.3[Pb] ; r = 0.911). This indicates that ALAD activity has considerable potential as a biomarker of Pb and moreover, in marine bivalve species with different feeding habits. Lead isotope data

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

International Nuclear Information System (INIS)

Deely, A.E.; Blackwell, B.A.B.; Mylroie, J.E.; Carew, J.L.; Blickstein, J.I.B.; Skinner, A.R.

2011-01-01

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.

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.

Persistent organic pollutants in four bivalve species from Svalbard waters

International Nuclear Information System (INIS)

Vieweg, Ireen; Hop, Haakon; Brey, Thomas; Huber, Sandra; Ambrose, William G.; Locke V, William L.; Gabrielsen, Geir W.

2012-01-01

Organochlorine compounds (OC) were determined in Arctic bivalves (Mya truncata, Serripes groenlandicus, Hiatella arctica and Chlamys islandica) from Svalbard with regard to differences in geographic location, species and variations related to their size and age. Higher chlorinated polychlorinated biphenyls (PCB 101–PCB 194), chlordanes and α-hexachlorocyclohexane (α-HCH) were consistently detected in the bivalves and PCBs dominated the OC load in the organisms. OC concentrations were highest in Mya truncata and the lowest in Serripes groenlandicus. Species-specific OC levels were likely related to differences in the species’ food source, as indicated by the δ 13 C results, rather than size and age. Higher OC concentrations were observed in bivalves from Kongsfjorden compared to the northern sampling locations Liefdefjorden and Sjuøyane. The spatial differences might be related to different water masses influencing Kongsfjorden (Atlantic) and the northern locations (Arctic), with differing phytoplankton bloom situations. - Highlights: ► Organochlorine compounds (OC) were analyzed in 4 bivalve species from Svalbard. ► Polychlorinated biphenyls dominated the OC load observed in the bivalves. ► Atlantic water influenced bivalves had higher OC levels than those from Arctic water. ► Location and species, rather than size and age, determined the OC pattern found. - New findings of organochlorines in Arctic bivalves that are central for evaluating the importance of geographical location and species for the organochlorine pattern in benthic organisms.

Molluscs and echinoderms aquaculture: biological aspects, current status, technical progress and future perspectives for the most promising species in Italy

Directory of Open Access Journals (Sweden)

Antonio Pais

2012-10-01

Full Text Available Shellfish aquaculture is a widespread activity in the Italian peninsula. However, only two bivalve species are mainly cultured along the coastline of that country: the Mediterranean mussel Mytilus galloprovincialis and the Manila clam Venerupis philippinarum (Ruditapes philippinarum. By contrast, just a few other mollusc species of commercial interest are scarcely reared at a small-scale level. After analysing the current status of Italian shellfish production, this paper reports and discusses the potential for culturing several different invertebrate species [i.e., the European flat oyster Ostrea edulis, the grooved carpet shell Venerupis decussata (Ruditapes decussatus, the razor clams Ensis minor and Solen marginatus, the cephalopod Octopus vulgaris, and the purple sea urchin Paracentrotus lividus] in this country. In addition, a detailed overview of the progress made in aquacultural techniques for these species in the Mediterranean basin is presented, highlighting the most relevant bottlenecks and the way forward to shift from the experimental to the aquaculture phase. Finally, an outlook of the main economic and environmental benefits arising from these shellfish culture practices is also given.

Epizootiology of Perkinsus sp. inCrassostrea gasar oysters in polyculture with shrimps in northeastern Brazil

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Patricia Mirella da Silva

2016-03-01

Full Text Available Abstract Bivalve culture is of considerable economic and social interest in northeastern (NE Brazil. The polyculture is an alternative approach to traditional monoculture for reducing the environmental impact of shrimp farming and improving oyster culture. Perkinsus marinus andPerkinsus olseni were found infecting oysters in NE Brazil and can threaten oyster production. This study evaluatedPerkinsus spp. occurrence in Crassostrea gasar during all production stages. Oyster spats were produced in a hatchery and grown in shrimp ponds in Rio Grande do Norte state.Perkinsus spp. were surveyed by Ray’s fluid thioglycollate medium and confirmed by polymerase chain reaction. Prevalence and intensity of infection were determined in oysters until they reached 7 cm. Results showed that the broodstock was already infected by Perkinsus (60%, but the derived spats were Perkinsus-free. Oyster spats acquired Perkinsus infection when transferred to ponds. The prevalence gradually increased in the seven months following placement in ponds (73%, and then decreased to 17% by the tenth month. The infections were initially mild, but intensity increased at the final growth stage. In conclusion, it is possible to produce Perkinsus-free C. gasar oyster spats from infected broodstock, and their culture in shrimp ponds is feasible.

Facultative parasitism by the bivalve Kurtiella pedroana in the sand crab Emerita analoga

Science.gov (United States)

Bhaduri, Ritin; Valentich-Scott, Paul; Hilgers, Mark; Singh, Rajvir; Hickman, Mikaila; Lafferty, Kevin D.

2017-01-01

It is rare that an organism capable of independent or commensalistic existence can also become endoparasitic on a host. In this study, we documented a potential step toward parasitism in the commensal clam Kurtiella pedroana (Bivalvia: Galeommatoidea). Galeommatoideans are known commensals of various invertebrates, including crustaceans. Emerita analoga (Decapoda: Hippidae) is an abundant intertidal decapod inhabiting sandy beaches of the Pacific coast of North and South America. Crabs collected from Monterey Bay, California, were measured and examined externally and internally for associated molluscs. Out of the 520 crabs, 37 large female individuals harbored 49 bivalves (prevalence of 7.11% and mean intensity of 1.3). Forty-one ectocommensal clams were either inside the crab's branchial chambers or on their lateroventral surfaces, and were attached by byssal threads. Our key finding was eight clams that lacked byssal threads and were living in the hemocoel. These internal clams were significantly smaller than the ectocommensals. Because these internal clams lacked access to their normal food, we hypothesize they might have fed on their host's hemolymph as would a parasite. This clam species likely can't reproduce inside its host, implying that endoparasitism is a dead-end state for K. pedroana. Facultative parasitism in a free-living or an ectocommensal is uncommon and suggests a pathway to parasitism.

Biomimetic and bio-inspired uses of mollusc shells.

Science.gov (United States)

Morris, J P; Wang, Y; Backeljau, T; Chapelle, G

2016-06-01

Climate change and ocean acidification are likely to have a profound effect on marine molluscs, which are of great ecological and economic importance. One process particularly sensitive to climate change is the formation of biominerals in mollusc shells. Fundamental research is broadening our understanding of the biomineralization process, as well as providing more informed predictions on the effects of climate change on marine molluscs. Such studies are important in their own right, but their value also extends to applied sciences. Biominerals, organic/inorganic hybrid materials with many remarkable physical and chemical properties, have been studied for decades, and the possibilities for future improved use of such materials for society are widely recognised. This article highlights the potential use of our understanding of the shell biomineralization process in novel bio-inspired and biomimetic applications. It also highlights the potential for the valorisation of shells produced as a by-product of the aquaculture industry. Studying shells and the formation of biominerals will inspire novel functional hybrid materials. It may also provide sustainable, ecologically- and economically-viable solutions to some of the problems created by current human resource exploitation. Copyright © 2016 Elsevier B.V. All rights reserved.

The use of yolk protein as biomarkers for endocrine disruption in molluscs

DEFF Research Database (Denmark)

Holbech, Henrik; Kinnberg, Karin Lund; Bjerregaard, Poul

Invertebrates and especially molluscs have received increasing attention in relation to endocrine disrupting chemicals (EDs) during the last few years and the development of OECD test guidelines to assess the effect of EDs with molluscs are in progress. One of the main problems with the development...

Use of side-scan sonar for estimations of Crassostrea brasiliana (Lamarck, 1819 stocks in subtidal banks on the south coast of Brazil

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Gisela Geraldine Castilho Westphal

2016-03-01

Full Text Available Abstract Uncontrolled extractivism has led to a worldwide reduction in oyster stocks. The use of new and more efficient management tools for impacted environments must increase. The application of such tools requires previous biological and environmental knowledge of the resident populations of these bivalve mollusks. Technical difficulties are usually associated with studies of submerged oyster banks, and these difficulties result in a considerable lack of biological data on the oysters that inhabit subtidal zones. This study aimed to survey Crassostrea brasiliana (also known as C. gasar stocks in submerged banks and to evaluate a method with which to measure the extent of the banks and identify and quantify the oysters in the banks with the use of side-scan sonar. This study was conducted on 10 oysters banks located in the subtidal zone of Guaratuba Bay, on the south coast of Brazil. The prospection of all these banks was later validated by diving, and oyster samples (n = 20/bank were collected for species identification with a molecular method. Only one bank contained oysters that were generically classified as Crassostrea sp.; those in the remaining banks being identified as C. brasiliana. The prospected banks contained oysters of various sizes (average 1.5 m, n = 1,107 that were heterogeneously scattered in the riverbeds. The total number of oysters in the 10 sampled banks was estimated to be 21,159.13 oysters or 1 oyster/4.5 m², which represents a low oyster density in the study site. The results validate the use of side-scan sonar as an efficient means with which to prospect for oysters in banks located within subtidal zones.

Metabolites of saxitoxin analogues in bivalves contaminated by Gymnodinium catenatum.

Science.gov (United States)

Vale, Paulo

2010-01-01

Bivalve metabolites of saxitoxin analogues, not present in microalgae, were recently described as an important toxin fraction in mussels contaminated by Alexandrium tamarense. These possess very low fluorescence, and require mass spectrometry detection. HILIC-MS was implemented to look for these metabolites in bivalves contaminated during Gymnodinium catenatum blooms at the Portuguese coast. The presence of M1 was tentatively identified in several bivalves, ranging from estuarine (Mytilus galloprovinciallis, Cerastoderma edule and Ruditapes decussatus) to oceanic habitat (Donax trunculus and Ensis spp.). It was hypothesized that M1 could contribute to an important fraction of the profile of STX analogues. M1 was more abundant in estuarine bivalves that retain longer PSP toxins, in the following order: mussels>cockles>clams. These data highlight that the study by fluorimetry alone of the carbamoyl, N-sulfocarbamoyl, and decarbamoyl families is manifestly insufficient to fully understand toxin dynamics in bivalves feeding on G. catenatum without a proper study of hydroxybenzoate and hydroxylated M-toxins.

Microbial Diseases of Bivalve Mollusks: Infections, Immunology and Antimicrobial Defense.

Science.gov (United States)

Zannella, Carla; Mosca, Francesco; Mariani, Francesca; Franci, Gianluigi; Folliero, Veronica; Galdiero, Marilena; Tiscar, Pietro Giorgio; Galdiero, Massimiliano

2017-06-17

A variety of bivalve mollusks (phylum Mollusca, class Bivalvia) constitute a prominent commodity in fisheries and aquacultures, but are also crucial in order to preserve our ecosystem's complexity and function. Bivalve mollusks, such as clams, mussels, oysters and scallops, are relevant bred species, and their global farming maintains a high incremental annual growth rate, representing a considerable proportion of the overall fishery activities. Bivalve mollusks are filter feeders; therefore by filtering a great quantity of water, they may bioaccumulate in their tissues a high number of microorganisms that can be considered infectious for humans and higher vertebrates. Moreover, since some pathogens are also able to infect bivalve mollusks, they are a threat for the entire mollusk farming industry. In consideration of the leading role in aquaculture and the growing financial importance of bivalve farming, much interest has been recently devoted to investigate the pathogenesis of infectious diseases of these mollusks in order to be prepared for public health emergencies and to avoid dreadful income losses. Several bacterial and viral pathogens will be described herein. Despite the minor complexity of the organization of the immune system of bivalves, compared to mammalian immune systems, a precise description of the different mechanisms that induce its activation and functioning is still missing. In the present review, a substantial consideration will be devoted in outlining the immune responses of bivalves and their repertoire of immune cells. Finally, we will focus on the description of antimicrobial peptides that have been identified and characterized in bivalve mollusks. Their structural and antimicrobial features are also of great interest for the biotechnology sector as antimicrobial templates to combat the increasing antibiotic-resistance of different pathogenic bacteria that plague the human population all over the world.

Ancient DNA analysis identifies marine mollusc shells as new metagenomic archives of the past.

Science.gov (United States)

Der Sarkissian, Clio; Pichereau, Vianney; Dupont, Catherine; Ilsøe, Peter C; Perrigault, Mickael; Butler, Paul; Chauvaud, Laurent; Eiríksson, Jón; Scourse, James; Paillard, Christine; Orlando, Ludovic

2017-09-01

Marine mollusc shells enclose a wealth of information on coastal organisms and their environment. Their life history traits as well as (palaeo-) environmental conditions, including temperature, food availability, salinity and pollution, can be traced through the analysis of their shell (micro-) structure and biogeochemical composition. Adding to this list, the DNA entrapped in shell carbonate biominerals potentially offers a novel and complementary proxy both for reconstructing palaeoenvironments and tracking mollusc evolutionary trajectories. Here, we assess this potential by applying DNA extraction, high-throughput shotgun DNA sequencing and metagenomic analyses to marine mollusc shells spanning the last ~7,000 years. We report successful DNA extraction from shells, including a variety of ancient specimens, and find that DNA recovery is highly dependent on their biomineral structure, carbonate layer preservation and disease state. We demonstrate positive taxonomic identification of mollusc species using a combination of mitochondrial DNA genomes, barcodes, genome-scale data and metagenomic approaches. We also find shell biominerals to contain a diversity of microbial DNA from the marine environment. Finally, we reconstruct genomic sequences of organisms closely related to the Vibrio tapetis bacteria from Manila clam shells previously diagnosed with Brown Ring Disease. Our results reveal marine mollusc shells as novel genetic archives of the past, which opens new perspectives in ancient DNA research, with the potential to reconstruct the evolutionary history of molluscs, microbial communities and pathogens in the face of environmental changes. Other future applications include conservation of endangered mollusc species and aquaculture management. © 2017 John Wiley & Sons Ltd.

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".

Plant indicator values as a tool for land mollusc autecology assessment

Science.gov (United States)

Horsák, Michal; Hájek, Michal; Tichý, Lubomír; Juřičková, Lucie

2007-09-01

The aim of this paper was to utilize Ellenberg's plant indicator system for assessing mollusc autecology and to highlight possibilities and advantages of that approach in the case of fen mollusc communities. Molluscs and plants from 137 fen sites in the Western Carpathian Mountains were recorded quantitatively from homogeneous areas of 16 m 2. Water conductivity and pH were measured in the field. Values of Ellenberg's "light, temperature, continentality, moisture, soil reaction, and nutrients" were estimated for each site. The whole data set was processed using ordinations (PCA, DCA, and CCA) and generalized additive models (GAMs). We observed a strong correlation between water pH and Ellenberg soil reaction estimated by plant indicator values ( r = 0.72, P < 0.001). Ellenberg soil reaction was found to be the best predictor of mollusc species composition, which expressed the main mineral-richness gradient. We found the existence of a second important gradient, the gradient of "light", expressing site and canopy openness. A tight correspondence between the results of species response curve modelling based on water conductivity and Ellenberg soil reaction confirmed that "soil reaction" does not express merely pH, but rather the total amount of calcium. We conclude that the Ellenberg's indicator system can be used to study the ecology of land molluscs, an important group of invertebrates in bioindication and nature conservation. Our data and approach could help design appropriate conservation management regimes for threatened snail species. We propose that our approach will be useful also in ecological studies of other animal groups.

Ecology and culturing of edible bivalves in Goa

Digital Repository Service at National Institute of Oceanography (India)

Parulekar, A.H.; Nair, S.A.; Ansari, Z.A.; Harkantra, S.N.; Chatterji, A.; Ingole, B.S.; Roy, J.M.

Environmental characteristics, growth rate, total production and technically feasible methods for the mass cultivation of Meretrix casta, Paphia malabarica, Villorita cyprinoides, Donax incarnatus, Perna viridis, Modiolus metcalfei and Crassostrea...

Mercury accumulation in marine bivalves: Influences of biodynamics and feeding niche

Energy Technology Data Exchange (ETDEWEB)

Pan Ke [Division of Life Science, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon (Hong Kong); Wang Wenxiong, E-mail: wwang@ust.hk [Division of Life Science, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon (Hong Kong)

2011-10-15

Differences in the accumulation of mercury (Hg) in five species of marine bivalves, including scallops Chlamys nobilis, clams Ruditapes philippinarum, oysters Saccostrea cucullata, green mussels Perna viridis, and black mussels Septifer virgatus, were investigated. The bivalves displayed different patterns of Hg accumulation in terms of the body concentrations of methylmercury (MeHg) and total Hg (THg), as well as the ratio of MeHg to THg. Parameters of the biodynamics of the accumulation of Hg(II) and MeHg could reflect the species-dependent Hg concentrations in the bivalves. With the exception of black mussels, we found a significant relationship between the efflux rates of Hg(II) and the THg concentrations in the bivalves. The interspecific variations in the MeHg to THg ratio were largely controlled by the relative difference between the elimination rates of Hg(II) and MeHg. Stable isotope ({delta}{sup 13}C) analysis indicated that the five bivalve species had contrasting feeding niches, which may also affect the Hg accumulation. - Highlights: > Significant difference in Hg accumulation and MeHg:THg ratio in different bivalves. > THg concentrations in the bivalves were generally related to the efflux rates of Hg(II). > Elimination of Hg(II) and MeHg controlled the interspecific variation in MeHg:THg ratio. > MeHg and THg concentrations reflect the interaction of Hg biodynamics and food. - The species-specific body concentrations of MeHg and THg in bivalves reflect the complicated interaction between the biodynamics of Hg(II) and MeHg and the different food sources.

Draft Genome of the Pearl Oyster Pinctada fucata: A Platform for Understanding Bivalve Biology

Science.gov (United States)

Takeuchi, Takeshi; Kawashima, Takeshi; Koyanagi, Ryo; Gyoja, Fuki; Tanaka, Makiko; Ikuta, Tetsuro; Shoguchi, Eiichi; Fujiwara, Mayuki; Shinzato, Chuya; Hisata, Kanako; Fujie, Manabu; Usami, Takeshi; Nagai, Kiyohito; Maeyama, Kaoru; Okamoto, Kikuhiko; Aoki, Hideo; Ishikawa, Takashi; Masaoka, Tetsuji; Fujiwara, Atushi; Endo, Kazuyoshi; Endo, Hirotoshi; Nagasawa, Hiromichi; Kinoshita, Shigeharu; Asakawa, Shuichi; Watabe, Shugo; Satoh, Nori

2012-01-01

The study of the pearl oyster Pinctada fucata is key to increasing our understanding of the molecular mechanisms involved in pearl biosynthesis and biology of bivalve molluscs. We sequenced ∼1150-Mb genome at ∼40-fold coverage using the Roche 454 GS-FLX and Illumina GAIIx sequencers. The sequences were assembled into contigs with N50 = 1.6 kb (total contig assembly reached to 1024 Mb) and scaffolds with N50 = 14.5 kb. The pearl oyster genome is AT-rich, with a GC content of 34%. DNA transposons, retrotransposons, and tandem repeat elements occupied 0.4, 1.5, and 7.9% of the genome, respectively (a total of 9.8%). Version 1.0 of the P. fucata draft genome contains 23 257 complete gene models, 70% of which are supported by the corresponding expressed sequence tags. The genes include those reported to have an association with bio-mineralization. Genes encoding transcription factors and signal transduction molecules are present in numbers comparable with genomes of other metazoans. Genome-wide molecular phylogeny suggests that the lophotrochozoan represents a distinct clade from ecdysozoans. Our draft genome of the pearl oyster thus provides a platform for the identification of selection markers and genes for calcification, knowledge of which will be important in the pearl industry. PMID:22315334

Effects of cyanobacteria Synechocystis spp. in the host-parasite model Crassostrea gasar–Perkinsus marinus

International Nuclear Information System (INIS)

Queiroga, Fernando Ramos; Marques-Santos, Luis Fernando; Hégaret, Hélène; Sassi, Roberto; Farias, Natanael Dantas; Santana, Lucas Nunes

2017-01-01

Highlights: • Synechocystis cyanobacteria cause functional weakness of oysters haemocytes. • Synechocystis cyanobacteria cause a strengthening of Perkinsus marinus. • Synechocystis cyanobacteria may contribute to an imbalance of P. marinus–Crassostrea gasar relationship. - Abstract: Perkinsosis is a disease caused by protozoan parasites from the Perkinsus genus. In Brazil, two species, P. beihaiensis and P. marinus, are frequently found infecting native oysters (Crassostrea gasar and C. rhizophorae) from cultured and wild populations in several states of the Northeast region. The impacts of this disease in bivalves from Brazil, as well as the interactions with environmental factors, are poorly studied. In the present work, we evaluated the in vitro effects of the cyanobacteria Synechocystis spp. on trophozoites of P. marinus and haemocytes of C. gasar. Four cyanobacteria strains isolated from the Northeast Brazilian coast were used as whole cultures (WCs) and extracellular products (ECPs). Trophozoites of P. marinus were exposed for short (4 h) and long (48 h and 7 days, the latter only for ECPs) periods, while haemocytes were exposed for a short period (4 h). Cellular and immune parameters, i.e. cell viability, cell count, reactive oxygen species production (ROS) and phagocytosis of inert (latex beads) and biological particles (zymosan and trophozoites of P. marinus) were measured by flow cytometry. The viability of P. marinus trophozoites was improved in response to WCs of Synechocystis spp., which could be a beneficial effect of the cyanobacteria providing nutrients and reducing reactive oxygen species. Long-term exposure of trophozoites to ECPs of cyanobacteria did not modify in vitro cell proliferation nor viability. In contrast, C. gasar haemocytes showed a reduction in cell viability when exposed to WCs, but not to ECPs. However, ROS production was not altered. Haemocyte ability to engulf latex particles was reduced when exposed mainly to ECPs of

Effects of cyanobacteria Synechocystis spp. in the host-parasite model Crassostrea gasar–Perkinsus marinus

Energy Technology Data Exchange (ETDEWEB)

Queiroga, Fernando Ramos [Laboratório de Imunologia e Patologia de Invertebrados (LABIPI), Departamento de Biologia Molecular, Universidade Federal da Paraíba, 58051-900, João Pessoa, Paraíba (Brazil); Marques-Santos, Luis Fernando [Laboratório de Biologia Celular e do Desenvolvimento (LABID), Departamento de Biologia Molecular, Universidade Federal da Paraíba, 58051-900, João Pessoa, Paraíba (Brazil); Hégaret, Hélène [Laboratoire des Sciences de l' Environnement Marin (LEMAR), UMR 6539 CNRS UBO IRD IFREMER, Institut Universitaire Européen de la Mer, Technopôle Brest-Iroise, 29280, Plouzané (France); Sassi, Roberto [Laboratório de Ambientes Recifais e Biotecnologia de Microalgas (LARBIM), Departamento de Sistemática e Ecologia, Universidade Federal da Paraíba, 58051-900, João Pessoa, Paraíba (Brazil); Farias, Natanael Dantas; Santana, Lucas Nunes [Laboratório de Imunologia e Patologia de Invertebrados (LABIPI), Departamento de Biologia Molecular, Universidade Federal da Paraíba, 58051-900, João Pessoa, Paraíba (Brazil); and others

2017-06-15

Highlights: • Synechocystis cyanobacteria cause functional weakness of oysters haemocytes. • Synechocystis cyanobacteria cause a strengthening of Perkinsus marinus. • Synechocystis cyanobacteria may contribute to an imbalance of P. marinus–Crassostrea gasar relationship. - Abstract: Perkinsosis is a disease caused by protozoan parasites from the Perkinsus genus. In Brazil, two species, P. beihaiensis and P. marinus, are frequently found infecting native oysters (Crassostrea gasar and C. rhizophorae) from cultured and wild populations in several states of the Northeast region. The impacts of this disease in bivalves from Brazil, as well as the interactions with environmental factors, are poorly studied. In the present work, we evaluated the in vitro effects of the cyanobacteria Synechocystis spp. on trophozoites of P. marinus and haemocytes of C. gasar. Four cyanobacteria strains isolated from the Northeast Brazilian coast were used as whole cultures (WCs) and extracellular products (ECPs). Trophozoites of P. marinus were exposed for short (4 h) and long (48 h and 7 days, the latter only for ECPs) periods, while haemocytes were exposed for a short period (4 h). Cellular and immune parameters, i.e. cell viability, cell count, reactive oxygen species production (ROS) and phagocytosis of inert (latex beads) and biological particles (zymosan and trophozoites of P. marinus) were measured by flow cytometry. The viability of P. marinus trophozoites was improved in response to WCs of Synechocystis spp., which could be a beneficial effect of the cyanobacteria providing nutrients and reducing reactive oxygen species. Long-term exposure of trophozoites to ECPs of cyanobacteria did not modify in vitro cell proliferation nor viability. In contrast, C. gasar haemocytes showed a reduction in cell viability when exposed to WCs, but not to ECPs. However, ROS production was not altered. Haemocyte ability to engulf latex particles was reduced when exposed mainly to ECPs of

Infectious diseases of marine molluscs and host responses as revealed by genomic tools

Science.gov (United States)

Ford, Susan E.

2016-01-01

More and more infectious diseases affect marine molluscs. Some diseases have impacted commercial species including MSX and Dermo of the eastern oyster, QPX of hard clams, withering syndrome of abalone and ostreid herpesvirus 1 (OsHV-1) infections of many molluscs. Although the exact transmission mechanisms are not well understood, human activities and associated environmental changes often correlate with increased disease prevalence. For instance, hatcheries and large-scale aquaculture create high host densities, which, along with increasing ocean temperature, might have contributed to OsHV-1 epizootics in scallops and oysters. A key to understanding linkages between the environment and disease is to understand how the environment affects the host immune system. Although we might be tempted to downplay the role of immunity in invertebrates, recent advances in genomics have provided insights into host and parasite genomes and revealed surprisingly sophisticated innate immune systems in molluscs. All major innate immune pathways are found in molluscs with many immune receptors, regulators and effectors expanded. The expanded gene families provide great diversity and complexity in innate immune response, which may be key to mollusc's defence against diverse pathogens in the absence of adaptive immunity. Further advances in host and parasite genomics should improve our understanding of genetic variation in parasite virulence and host disease resistance. PMID:26880838

Characterization of receptor of activated C kinase 1 (RACK1) and functional analysis during larval metamorphosis of the oyster Crassostrea angulata.

Science.gov (United States)

Yang, Bingye; Pu, Fei; Qin, Ji; You, Weiwei; Ke, Caihuan

2014-03-10

During a large-scale screen of the larval transcriptome library of the Portuguese oyster, Crassostrea angulata, the oyster gene RACK, which encodes a receptor of activated protein kinase C protein was isolated and characterized. The cDNA is 1,148 bp long and has a predicted open reading frame encoding 317 aa. The predicted protein shows high sequence identity to many RACK proteins of different organisms including molluscs, fish, amphibians and mammals, suggesting that it is conserved during evolution. The structural analysis of the Ca-RACK1 genomic sequence implies that the Ca-RACK1 gene has seven exons and six introns, extending approximately 6.5 kb in length. It is expressed ubiquitously in many oyster tissues as detected by RT-PCR analysis. The Ca-RACK1 mRNA expression pattern was markedly increased at larval metamorphosis; and was further increased along with Ca-RACK1 protein synthesis during epinephrine-induced metamorphosis. These results indicate that the Ca-RACK1 plays an important role in tissue differentiation and/or in cell growth during larval metamorphosis in the oyster, C. angulata. Copyright © 2013 Elsevier B.V. All rights reserved.

A study on the distribution of alpha emitting radionuclides Polonium-210 in the Pitchavaram mangrove forest, southeast coast of India (Bay of Bengal)

International Nuclear Information System (INIS)

Raja, P.; Sadiq Bukhari, A.; Krishnamoorthy, R.; Shahul Hameed, M.M.; Shahul Hameed, P.

2004-01-01

The environmental samples such as water, sediment and biota (prawns, crabs, bivalves and fishes) were collected from Pitchavaram mangrove ecosystem and subjected to analyses of 210 Po. The concentration of 210 Po in water and sediment was 1.8 mBq/l and 2.6 Bq/kg respectively. It was observed that the muscle and soft tissues of animals concentrated a higher level of 210 Po than the hard parts like shells and bones. The ranges of 210 Po activity in biological samples were analysed in crustaceans (muscle: 72.3-227.7 Bq/kg and exoskeleton 31.2-92.3 Bq/kg), molluscs (soft tissue: 295-584.7 Bq/kg and shell: 2.9-11.9 Bq/kg) and fishes (muscle: 14.3- 43.7 Bq/kg and bone: 10.3-21.9 Bq/kg). The oyster Crassostrea madrasensis was identified to concentrate higher level of 210 Po in their soft tissues, suggesting that this could serve as a bioindicator organism. The study demonstrates that the 210 Po Pitchavaram mangrove has been rather very low as compared to adjacent Kalpakkam coast on the North and Gulf of Mannar on the South. (author)

Functional analysis of a tyrosinase gene involved in early larval shell biogenesis in Crassostrea angulata and its response to ocean acidification.

Science.gov (United States)

Yang, Bingye; Pu, Fei; Li, Lingling; You, Weiwei; Ke, Caihuan; Feng, Danqing

2017-04-01

The formation of the primary shell is a vital process in marine bivalves. Ocean acidification largely influences shell formation. It has been reported that enzymes involved in phenol oxidation, such as tyrosinase and phenoloxidases, participate in the formation of the periostracum. In the present study, we cloned a tyrosinase gene from Crassostrea angulata named Ca-tyrA1, and its potential function in early larval shell biogenesis was investigated. The Ca-tyrA1 gene has a full-length cDNA of 2430bp in size, with an open reading frame of 1896bp in size, which encodes a 631-amino acid protein that includes a 24-amino acid putative signal peptide. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis revealed that Ca-tyrA1 transcription mainly occurs at the trochophore stage, and the Ca-tyrA1 mRNA levels in the 3000ppm treatment group were significantly upregulated in the early D-veliger larvae. WMISH and electron scanning microscopy analyses showed that the expression of Ca-tyrA1 occurs at the gastrula stage, thereby sustaining the early D-veliger larvae, and the shape of its signal is saddle-like, similar to that observed under an electron scanning microscope. Furthermore, the RNA interference has shown that the treatment group has a higher deformity rate than that of the control, thereby indicating that Ca-tyrA1 participates in the biogenesis of the primary shell. In conclusion, and our results indicate that Ca-tyrA1 plays a vital role in the formation of the larval shell and participates in the response to larval shell damages in Crassostrea angulata that were induced by ocean acidification. Copyright © 2017 Elsevier Inc. All rights reserved.

Predicting the Response of Molluscs to the Impact of Ocean Acidification

Directory of Open Access Journals (Sweden)

John M. Wright

2013-04-01

Full Text Available Elevations in atmospheric carbon dioxide (CO2 are anticipated to acidify oceans because of fundamental changes in ocean chemistry created by CO2 absorption from the atmosphere. Over the next century, these elevated concentrations of atmospheric CO2 are expected to result in a reduction of the surface ocean waters from 8.1 to 7.7 units as well as a reduction in carbonate ion (CO32− concentration. The potential impact that this change in ocean chemistry will have on marine and estuarine organisms and ecosystems is a growing concern for scientists worldwide. While species-specific responses to ocean acidification are widespread across a number of marine taxa, molluscs are one animal phylum with many species which are particularly vulnerable across a number of life-history stages. Molluscs make up the second largest animal phylum on earth with 30,000 species and are a major producer of CaCO3. Molluscs also provide essential ecosystem services including habitat structure and food for benthic organisms (i.e., mussel and oyster beds, purification of water through filtration and are economically valuable. Even sub lethal impacts on molluscs due to climate changed oceans will have serious consequences for global protein sources and marine ecosystems.

Predicting the Response of Molluscs to the Impact of Ocean Acidification

Science.gov (United States)

Parker, Laura M.; Ross, Pauline M.; O’Connor, Wayne A.; Pörtner, Hans O.; Scanes, Elliot; Wright, John M.

2013-01-01

Elevations in atmospheric carbon dioxide (CO2) are anticipated to acidify oceans because of fundamental changes in ocean chemistry created by CO2 absorption from the atmosphere. Over the next century, these elevated concentrations of atmospheric CO2 are expected to result in a reduction of the surface ocean waters from 8.1 to 7.7 units as well as a reduction in carbonate ion (CO32−) concentration. The potential impact that this change in ocean chemistry will have on marine and estuarine organisms and ecosystems is a growing concern for scientists worldwide. While species-specific responses to ocean acidification are widespread across a number of marine taxa, molluscs are one animal phylum with many species which are particularly vulnerable across a number of life-history stages. Molluscs make up the second largest animal phylum on earth with 30,000 species and are a major producer of CaCO3. Molluscs also provide essential ecosystem services including habitat structure and food for benthic organisms (i.e., mussel and oyster beds), purification of water through filtration and are economically valuable. Even sub lethal impacts on molluscs due to climate changed oceans will have serious consequences for global protein sources and marine ecosystems. PMID:24832802

An evaluation of intertidal feeding habitats from a shorebird perspective: Towards relevant comparisons between temperate and tropical mudflats

Science.gov (United States)

Piersma, Theunis; de Goeij, Petra; Tulp, Ingrid

Macrozoobenthic communities of intertidal soft sediments are reviewed worldwide from the perspective of a mollusc-eating shorebird species. Based on 19 sites, total biomass figures varied between 5 and 80 g AFDM per m 2 (average 24 g AFDM per m 2); no latitudinal trends are apparent. The contribution made by bivalves and gastropods varies between 1% and 99%, north-temperate intertidal flats having relatively more molluscs than tropical flats. Intertidal flats in the tropics contain a greater variety of taxa, with brachiopods in Indonesia and echinoderms in northwest Australia contributing significantly to biomass only there. Limits to the occurrence of avian predators of intertidal benthos are set by the harvestable fraction of the biomass on offer and the costs of living at a particular site. No systematic differences in the harvestable fraction of the total mollusc-biomass for a worldwide occurring shorebird species specializing on molluscs (knots Calidris canutus) were apparent between temperate and tropical intertidal areas, in spite of large differences in maintenance metabolism incurred by these birds. The harvestable fractions of bivalves in the two West African areas (Banc d'Arguin, Mauritania and Guinea-Bissau) tended to be high (23-84% of total biomass in six species), they were relatively low (2-52% in five species) in the temperate Wadden Sea and the tropical northwest Australian site. Harvestable biomass determines the intake rate of shorebirds, as illustrated by functional-response curves of knots feeding on two bivalves species. We argue that the collection of information on size-depth relationships along with faunal and biomass surveys at a range of sites is bound to greatly increase our understanding of both the biology of tidal-flat invertebrates and the resource base underpinning the spectacular seasonal migrations of shorebirds.

Antimicrobial peptides in marine invertebrate health and disease

OpenAIRE

Destoumieux-Garzón, Delphine; Rosa, Rafael Diego; Schmitt, Paulina; Barreto, Cairé; Vidal-Dupiol, Jeremie; Mitta, Guillaume; Gueguen, Yannick; Bachère, Evelyne

2016-01-01

Aquaculture contributes more than one-third of the animal protein from marine sources worldwide. A significant proportion of aquaculture products are derived from marine protostomes that are commonly referred to as ‘marine invertebrates’. Among them, penaeid shrimp (Ecdysozosoa, Arthropoda) and bivalve molluscs (Lophotrochozoa, Mollusca) are economically important. Mass rearing of arthropods and molluscs causes problems with pathogens in aquatic ecosystems that are exploited by humans. Remark...

JST Thesaurus Headwords and Synonyms: Crassostrea gigas [MeCab user dictionary for science technology term[Archive

Lifescience Database Archive (English)

Full Text Available MeCab user dictionary for science technology term Crassostrea gigas 名詞 一般 * * * * マ...ガキ マガキ マガキ Thesaurus2015 200906057106354047 C LS05 UNKNOWN_2 Crassostrea gigas

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

International Nuclear Information System (INIS)

Mu, D.H.; Yan, S.P.; Gu, Y.J.; Li, D.J.; Du, J.Z.

2007-01-01

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)

Effect of marine contamination on the genetic population structure of the bivalve Crassostrea angulata; Efecto de la contaminacion marina sobre la estructura genetica poblacional del bivalvo Crassostrea angulata

Energy Technology Data Exchange (ETDEWEB)

Cross, Ismael; Rebordinos, Laureana [Laboratorio de Genetica, Facultad de Ciencias del Mar, Universidad de Cadiz, Cadiz (Spain)

2003-06-15

Seven enzyme loci were analyzed in three natural populations of Crassostrea angulata located on the southern Atlantic coast of the Iberian Peninsula. Two of the populations showed distinct levels of contamination by heavy metals, whereas the third was not contaminated and served as control. These seven loci were shown to be very variable in terms of the number of alleles, polymorphism and average heterozygosity. The Lap and Mdh1 loci presented null alleles. A significant positive correlation was found between the number of alleles and the concentration of iron that was fitted to a model of linear regression. However, this correlation was negative for the heterozygosity, and significant for cadmium and zinc. The Em, Lap, Mdh1 y Xdh loci showed a deficit of heterozygotes in all the populations. The values of heterozygotic deficit (D) were statistically significant between the contaminated populations and the control for Mdh1 and very close to a significant level for Em. In Pgm, a heterozygotic excess appeared in the control population and deficit, which was correlated to the increased levels of metal concentration, occurred in the other two populations. The differences between the D values of the three populations were also significant in this locus. Positive, negative and significant relationships were obtained between the concentration of metals and some alleles of the Em, Lap and Pgm loci. Also, the homozygotic genotypes of the alleles with positive correlation values were selected in the contaminated areas, while the heterozygotes were more favoured in the control population, showing an adaptive behavior and corroborating the utility of some of these loci as biomarkers in studies of population dynamics in areas subjected to environmental contamination. [Spanish] Se analizaron siete loci alozimicos en tres poblaciones naturales de Crassostrea angulata localizadas en la costa suratlantica de la Peninsula Iberica. Dos de las poblaciones mostraban distintos niveles

Human norovirus RNA persists in seawater under simulated winter conditions but does not bioaccumulate efficiently in Pacific Oysters (Crassostrea gigas).

Science.gov (United States)

Dancer, D; Rangdale, R E; Lowther, J A; Lees, D N

2010-11-01

Norovirus (NoV) is the principal agent of bivalve molluscan shellfish-associated gastroenteric illness worldwide. Currently, noncultivable human NoVs can be detected in bivalve molluscan shellfish by using molecular methods such as real-time reverse transcription PCR assays (qRT-PCR). In addition to infectious viruses, this methodology may also detect noninfectious NoV, including fragments of the NoV genome. This study addresses, in part, the implications of qRT-PCR results for the detection of NoV in shellfish in the absence of an infectivity assay. To evaluate environmental persistence, the stability of a short fragment of the NoV genome, spanning the qRT-PCR target in the open reading frame 1/2 junction, was assessed in seawater under artificial environmental conditions simulating winter in the United Kingdom (1 mW/cm² UV irradiation, 8°C) during a 4-week period. Detectable RNA levels decreased exponentially (T₉₀ of approximately 141 h); however, sequences were still detectable for up to 2 weeks. The ability of Pacific oysters (Crassostrea gigas) to bioaccumulate NoV particles (from human feces) and RNA fragments was also compared using qRT-PCR. Oysters exposed to NoV particles subsequently were positive for NoV by qRT-PCR at levels several orders of magnitude in excess of the theoretical limit of detection, whereas oysters exposed to similar quantities of NoV RNA were either negative or positive at significantly lower levels. Therefore, although noninfectious fragments of NoV RNA may persist in the environment under winter conditions, this type of material will not be efficiently bioaccumulated by Pacific oysters and should not significantly contribute to positive qRT-PCR results.

Galeommatid bivalves from Phuket, Thailand

DEFF Research Database (Denmark)

Lützen, Jørgen; Nielsen, Claus

2005-01-01

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

FMRFamide-like immunoreactivity in the central nervous system of the cephalopod mollusc, Idiosepius notoides

DEFF Research Database (Denmark)

Wollesen, Tim; Loesel, R.; Wanninger, Andreas Wilhelm Georg

2008-01-01

For more than a century, cephalopod molluscs have been the subject of extensive studies with respect to their complex neuroanatomy and behavior. In comparison to gastropod molluscs surprisingly little work has been carried out on the characterization of neurons in the central nervous system (CNS...

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., 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 fractionation

Transcriptome of American oysters, Crassostrea virginica, in response to bacterial challenge: insights into potential mechanisms of disease resistance.

Science.gov (United States)

McDowell, Ian C; Nikapitiya, Chamilani; Aguiar, Derek; Lane, Christopher E; Istrail, Sorin; Gomez-Chiarri, Marta

2014-01-01

The American oyster Crassostrea virginica, an ecologically and economically important estuarine organism, can suffer high mortalities in areas in the Northeast United States due to Roseovarius Oyster Disease (ROD), caused by the gram-negative bacterial pathogen Roseovarius crassostreae. The goals of this research were to provide insights into: 1) the responses of American oysters to R. crassostreae, and 2) potential mechanisms of resistance or susceptibility to ROD. The responses of oysters to bacterial challenge were characterized by exposing oysters from ROD-resistant and susceptible families to R. crassostreae, followed by high-throughput sequencing of cDNA samples from various timepoints after disease challenge. Sequence data was assembled into a reference transcriptome and analyzed through differential gene expression and functional enrichment to uncover genes and processes potentially involved in responses to ROD in the American oyster. While susceptible oysters experienced constant levels of mortality when challenged with R. crassostreae, resistant oysters showed levels of mortality similar to non-challenged oysters. Oysters exposed to R. crassostreae showed differential expression of transcripts involved in immune recognition, signaling, protease inhibition, detoxification, and apoptosis. Transcripts involved in metabolism were enriched in susceptible oysters, suggesting that bacterial infection places a large metabolic demand on these oysters. Transcripts differentially expressed in resistant oysters in response to infection included the immune modulators IL-17 and arginase, as well as several genes involved in extracellular matrix remodeling. The identification of potential genes and processes responsible for defense against R. crassostreae in the American oyster provides insights into potential mechanisms of disease resistance.

INVENTORY AND DISTRIBUTION OF MOLLUSC IN CORAL REEF OF BACAN ISLAND WATERS, NORTH MALUKU PROVINCE

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Hendrik A.W. Cappenberg

2017-11-01

Full Text Available Bacan Island waters of North Maluku Province consisted of three main tropical ecosystems, namely mangrove, seagrass, and coral reef with the highest marine biodiversity. Mollusc is a group of marine fauna that most of them associated with coral reef.  However, little is known about their information in the Bacan Island due to lack of study conducted there. The purpose of this study is to observe the diversity and distribution of mollusc fauna in the coral reef flat of Bacan Island. Mollusc inventory was done using Rapid Reef Resource Assessment (RRA method by snorkling in the reefs of east coast (25 sites and west coast (10 sites of Bacan Island. The molluscs found were directly identified into species level and recorded.  Results of inventory show that there are 47 species belong to 19 families with the family of Muricidae is the highest diversity (6 species, while the lowest are Buccinidae, Bursidae, Haliotidae, Olividae, Cardiidae, Isognomonidae and Spondylidae, respectively with only 1 species in each of those families. The highest species number of mollusc was distributed along the east coast of the island (40 species, and the lowest one was in the west coast (37 species. Some species such as Tridacna spp., Pinctada margaritifera and Pteria penguin are important species, because they have economical values. Keywords:       biodiversity, molluscs, coral reef, Bacan Island, North Maluku

Polonium-210 in marine bivalves inhabiting a wedge bank region, South India

International Nuclear Information System (INIS)

Feroz Khan, M.; Godwin Wesley, S.; Rajan, M.P.

2013-01-01

Determination of background radiation dose-rate is important in the process of assessing risks to the environment from exposure to living organisms both in terms of deriving the incremental dose-rate and as a point of reference for evaluating the significance of the exposure level. In the present study, 210 Po was quantified in two species of bivalve mollusks commonly available from so called a 'wedge bank region' of southern tip of India. Based on the activity concentration in media and in the whole body, an external and internal dose rate assessment to green mussel Perna viridis and brown mussel Perna indica due to 210 Po was derived using ERICA assessment tool. The samples were collected at the intertidal region along the wedge bank region of southern tip of India during 2009 to 2010. The measurement contributes to a better knowledge of these elements, since no data exists in this region. 5-10 g of each tissue sample was wet-digested using 70% concentrated HNO 3 followed by the addition of 40% H 2 O 2 along with 20 8Po tracer (0.2 Bq). The normality of the data set was checked using Lilliefors test (ne''50) and potential outliers, if any, were tested using Walsh's test (n>60). Using the measured 210 Po activity in molluscs, sediments and seawater, dose assessment was performed using the Tier 2 ERICA environment dose assessment tool 1.0

Study on the bioaccumulation of Polonium-210 on bivalve indicator organisms of Tamilnadu and Pondicherry coast (East Coast of India)

International Nuclear Information System (INIS)

Syed Mohamed, H.E.; Sadiq Bukhari, A.; Meeramaideen, M.; Masilamani, V.; Shamsudin, Mohamed; Shahul Hameed, P.

2012-01-01

210 Po is a major contributor (90%) of the natural radiation dose from alpha-emitting radionuclides, received by most marine organisms. Among marine organisms, benthic fauna are superior to many other biological groups, since they could be monitored due to their sedentary habits and then must either adapt to environmental stress or perish. They also reflect the water conditions not only at the time of sampling but also for some past time as well. The affinity of 210 Po for protein enables it to pass through the food chain, and increased body burdens of 210 Po have been found where diets include protein-rich meat and seafood. The present study was launched to evaluate the rate of accumulation of 210 Po in the benthic bivalve molluscs such as Perna indica, P.viridis, Meretrix casta, Cardium coronatum, Gafrarium tumidum, Paphia textrix, Vellorita cyprinodea and Pinctada sp., of Tamilnadu and Pondicherry coast. Water samples, sediments and bivalves were collected from Gulf of Mannar (6 sampling stations), Palk Strait (8 sampling stations) of Tamilnadu and Pondicherry (6 sampling stations). 210 Po determination as made was as per standard protocols. The results showed that 210 Po concentration in coastal waters of Gulf of Mannar, Palk Strait and Pondicherry ranged 0.5 - 2.83 mBq/l (mean 1.33 mBq/I), 2.14 - 32.14 mBq/l (mean 15.3 mBq/l) and 1.36 - 2.0 mBq/1 (mean 1.59 mBq/1) respectively. The sediments maintained higher level of 210 Po (mean value of 3.62 Bq/kg in Gulf of Mannar, 107.9 Bq/kg in Palk Strait and 3.0 Bq/kg in Pondicherry) than water. The 210 Po rich sediment therefore serves as a vital link in the transfer of Polonium from water to the marine organisms. The concentration of 210 Po in eight species of bivalves collected from the study area, recorded a maximum level ranging from 65.2 to 2668.9 Bq/kg in soft tissues and from 1.19 to 15.3 Bq/kg in shells. The bioaccumulation ability in bivalve species with reference to 210 Po was observed to be highly variable

JST Thesaurus Headwords and Synonyms: Crassostrea virginica [MeCab user dictionary for science technology term[Archive

Lifescience Database Archive (English)

Full Text Available MeCab user dictionary for science technology term Crassostrea virginica 名詞 一般 * * *... * アメリカガキ アメリカガキ アメリカガキ Thesaurus2015 200906044164726189 C LS05 UNKNOWN_2 Crassostrea virginica

Perkinsus sp. infecting the oyster Crassostrea rhizophorae from estuaries of the septentrional Northeast, Brazil

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M. P. Dantas-Neto

Full Text Available Abstract The mangrove oyster Crassostrea rhizophorae is an estuarine resource exploited by riverside communities in Northeast Brazil. Despite its socioeconomic importance, studies on the health status of this bivalve are scanty in this region. The purpose of the present study was to investigate the presence of the protozoan Perkinsus sp. in C. rhizophorae collected in August and September 2011 in three estuaries of the septentrional Northeast, Brazil: Jaguaribe (Ceará, Camurupim (Piauí and Carnaubeiras (Maranhão (n= 150 specimens/site. The samples were submitted to Ray’s fluid thioglycollate medium (RFTM, PCR and histology assays. The RFTM assay revealed spherical, blue or bluish-black hypnospores of the genus Perkinsus in 50 specimens (Jaguaribe= 17.3%, Camurupim= 5.3%, Carnaubeiras= 10.6%. The intensity of the infection ranged from very light (1-10 cells per slide to severe (more than 40 cells in each of 10 fields of the slide for Jaguaribe; very light for Camurupim and very light to moderate (at least 40 cells observed in each of 10 fields of the slide for Carnaubeiras. When submitted to confirmatory PCR analysis, 6 cases were confirmed (Jaguaribe=3, Camurupim=1, Carnaubeiras=2. The histology confirmed 21 cases of infection in specimens from the three estuaries. Although local collectors have reported no mortality in oyster populations that might be attributed to infection by Perkinsus, health surveillance of oyster populations in the septentrional region of Northeast Brazil is advisable.

Reconstructing diet composition on the basis of faeces in a mollusc-eating wader, the Knot Calidris canutus

NARCIS (Netherlands)

Dekinga, A.; Piersma, T.

1993-01-01

Methods are described to assess the molluscan diet of Knots feeding on intertidal flats in western Europe from their faecal output. The size distributions of two common bivalve prey, Macoma balthica and Cerastoderma edule, can be estimated from the heights of shell hinges retrieved from droppings.

Prospecção de moluscos bivalves no estudo da poluição dos rios Cachoeira e Santana em Ilhéus, Bahia, Brasil

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Denise Sande

2010-06-01

Full Text Available A survey about the pollution level of the Cachoeira and Santana Rivers (Ilheus, Bahia, Brazil was performed for a quarter, through the assessment of the microbiological quality of water and seafood (Crassostrea rhizophorae - oyster and Tagelus plebeius - razor clam extracted from these rivers. Traditional indicators of pollution such as total coliforms (Ct and thermtolerant coliforms (CT, and total count of micro-organisms, with isolation and identification of Enterobacteriaceae were determined in rivers samples, which exhibited different levels of faecal pollution. An amount of 68 micro-organisms was isolated, distributed in ten species, among them, Salmonella typhi, Escherichia coli and Shigella sp., warning about the risk of consuming these shellfish in nature, even when there is accordance with the laws established for CT. The bivalve prospection to monitor pollution levels was not effective considering CT detection in oysters and moapens. There was also the highest contamination degree in the Cachoeira River, which is used for water distribution in the region and as livelihood source through extractive activities for the riverside population.

Parasitas em ostras de cultivo (Crassostrea rhizophorae e Crassostrea gigas da Ponta do Sambaqui, Florianópolis, SC Parasites in cultured oysters (Crassostrea rhizophorae and Crassostrea gigas from Ponta do Sambaqui, Florianópolis, SC

Directory of Open Access Journals (Sweden)

R.C. Sabry

2005-09-01

Full Text Available Estudou-se a presença de parasitas e realizaram-se exames macroscópicos e histológicos em ostras (Crassostrea rhizophorae e Crassostrea gigas cultivadas. Entre agosto de 2002 a maio de 2003, 30 indivíduos adultos de cada espécie foram coletados sazonalmente, totalizando 240 ostras. Os animais, provenientes de desova em laboratório, foram mantidos em lanternas de cultivo, em sistema suspenso tipo espinhel, com densidade de 40 ostras/andar. A cada coleta era registrada a mortalidade das ostras, a temperatura e a salinidade da água. A temperatura variou de 19 a 28,5°C e a salinidade, 31 a 35‰. A mortalidade foi de 48,3% para C. gigas e 70,8% para C. rhizophorae. A infestação pelo poliqueta Polydora websteri em C. gigas foi 100% durante todo o período e em C. rhizophorae, 100% em fevereiro e maio. O mal do pé foi observado em novembro (3,3% e maio (23,3% em C. gigas e maio (6,6% em C. rhizophorae. As maiores prevalências do protozoário Nematopsis sp. foram de 70 e 60% em C. gigas e C. rhizophorae, respectivamente. O protozoário Trichodina sp. ocorreu em 1,6% de C. rhizophorae, e larvas do cestóide Tylocephalum sp. foram observadas em 2,5% de C. gigas. Nenhum dos parasitas encontrados foi associado à mortalidade das ostras.Over a 10-month period, cultured oysters (Crassostrea rhizophorae and Crassostrea gigas from Ponta do Sambaqui, Florianopolis, Santa Catarina State were evaluated microscopically and histologically for parasite infection. Thirty mature individuals of each species were examined each season, for a total of 240 oysters. The animals, which originated from laboratory spawning, were kept in culture lanterns suspended in long-line systems at a density of 40 oysters per floor. Mortality, water temperature (19 to 28.5 ºC range and salinity (31 to 35‰ were recorded at each sampling. The total amount of dead oysters was 58 (48.3% to C. gigas and 85 (70.8% to C. rhizophorae. All C. gigas individuals were infected with

Accumulation of diarrhetic shellfish poisoning toxins in the oyster ...

African Journals Online (AJOL)

Diarrhetic shellfish poisoning (DSP) poses a significant threat to the safe consumption of shellfish in the southern Benguela ecosystem. The accumulation of DSP toxins was investigated in two cultivated bivalve species, the Pacific oyster Crassostrea gigas and the mussel Choromytilus meridionalis, suspended from a ...

Large-Scale Trade in Legally Protected Marine Mollusc Shells from Java and Bali, Indonesia.

Science.gov (United States)

Nijman, Vincent; Spaan, Denise; Nekaris, K Anne-Isola

2015-01-01

Tropical marine molluscs are traded globally. Larger species with slow life histories are under threat from over-exploitation. We report on the trade in protected marine mollusc shells in and from Java and Bali, Indonesia. Since 1987 twelve species of marine molluscs are protected under Indonesian law to shield them from overexploitation. Despite this protection they are traded openly in large volumes. We collected data on species composition, origins, volumes and prices at two large open markets (2013), collected data from wholesale traders (2013), and compiled seizure data by the Indonesian authorities (2008-2013). All twelve protected species were observed in trade. Smaller species were traded for Java and Bali, but the trade involves networks stretching hundreds of kilometres throughout Indonesia. Wholesale traders offer protected marine mollusc shells for the export market by the container or by the metric ton. Data from 20 confiscated shipments show an on-going trade in these molluscs. Over 42,000 shells were seized over a 5-year period, with a retail value of USD700,000 within Indonesia; horned helmet (Cassis cornuta) (>32,000 shells valued at USD500,000), chambered nautilus (Nautilus pompilius) (>3,000 shells, USD60,000) and giant clams (Tridacna spp.) (>2,000 shells, USD45,000) were traded in largest volumes. Two-thirds of this trade was destined for international markets, including in the USA and Asia-Pacific region. We demonstrated that the trade in protected marine mollusc shells in Indonesia is not controlled nor monitored, that it involves large volumes, and that networks of shell collectors, traders, middlemen and exporters span the globe. This impedes protection of these species on the ground and calls into question the effectiveness of protected species management in Indonesia; solutions are unlikely to be found only in Indonesia and must involve the cooperation of importing countries.

Large-Scale Trade in Legally Protected Marine Mollusc Shells from Java and Bali, Indonesia

Science.gov (United States)

Nijman, Vincent; Spaan, Denise; Nekaris, K. Anne-Isola

2015-01-01

Background Tropical marine molluscs are traded globally. Larger species with slow life histories are under threat from over-exploitation. We report on the trade in protected marine mollusc shells in and from Java and Bali, Indonesia. Since 1987 twelve species of marine molluscs are protected under Indonesian law to shield them from overexploitation. Despite this protection they are traded openly in large volumes. Methodology/Principal Findings We collected data on species composition, origins, volumes and prices at two large open markets (2013), collected data from wholesale traders (2013), and compiled seizure data by the Indonesian authorities (2008–2013). All twelve protected species were observed in trade. Smaller species were traded for trade involves networks stretching hundreds of kilometres throughout Indonesia. Wholesale traders offer protected marine mollusc shells for the export market by the container or by the metric ton. Data from 20 confiscated shipments show an on-going trade in these molluscs. Over 42,000 shells were seized over a 5-year period, with a retail value of USD700,000 within Indonesia; horned helmet (Cassis cornuta) (>32,000 shells valued at USD500,000), chambered nautilus (Nautilus pompilius) (>3,000 shells, USD60,000) and giant clams (Tridacna spp.) (>2,000 shells, USD45,000) were traded in largest volumes. Two-thirds of this trade was destined for international markets, including in the USA and Asia-Pacific region. Conclusions/Significance We demonstrated that the trade in protected marine mollusc shells in Indonesia is not controlled nor monitored, that it involves large volumes, and that networks of shell collectors, traders, middlemen and exporters span the globe. This impedes protection of these species on the ground and calls into question the effectiveness of protected species management in Indonesia; solutions are unlikely to be found only in Indonesia and must involve the cooperation of importing countries. PMID:26717021

Petroleum hydrocarbon concentrations in eight mollusc species along Tamilnadu coast, Bay of Bengal, India.

Science.gov (United States)

Veerasingam, S; Venkatachalapathy, R; Sudhakar, S; Raja, P; Rajeswari, V

2011-01-01

Eight mollusc species and sediment samples collected from three different stations along Tamilnadu coast, Bay of Bengal, India were analysed for the levels of petroleum hydrocarbons to elucidate the status of the petroleum residues in mollusc meant for human consumption. The concentrations of petroleum hydrocarbons in sediments along Tamilnadu coast varied from 5.04-25.5 microg/g dw (dry weight). High concentration of petroleum hydrocarbons in the sediment of Uppanar estuary (25.5 +/- 1.45 microg/g dw) was perhaps land and marine based anthropogenic sources of this region. The petroleum hydrocarbon residues in eight mollusc species collected from Uppanar, Vellar and Coleroon estuaries varied between 2.44-6.04 microg/g ww (wet weight). Although the concentration of petroleum hydrocarbons in sediment of the Uppanar region was markedly higher than the background, the petroleum hydrocarbon residues in mollusc collected from Uppanar estuary did not suggest bioaccumulation. The results signified that industrial growth has affected the aquatic environments and regular monitoring will help to adopt stringent pollution control measures for better management of the aquatic region.

Book review of Littler DM. Littler MM (2000) Caribbean Reef Plants An Identification Guide to the Reef Plants of the Caribbean, Bahamas, Florida and Gulf of Mexico

Science.gov (United States)

Zuschin, M.; Hohenegger, J.; Steininger, F.

2001-09-01

Information on spatial variability and distribution patterns of organisms in coral reef environments is necessary to evaluate the increasing anthropogenic disturbance of marine environments (Richmond 1993; Wilkinson 1993; Dayton 1994). Therefore different types of subtidal, reef-associated hard substrata (reef flats, reef slopes, coral carpets, coral patches, rock grounds), each with different coral associations, were investigated to determine the distribution pattern of molluscs and their life habits (feeding strategies and substrate relations). The molluscs were strongly dominated by taxa with distinct relations to corals, and five assemblages were differentiated. The Dendropoma maxima assemblage on reef flats is a discrete entity, strongly dominated by this encrusting and suspension-feeding gastropod. All other assemblages are arranged along a substrate gradient of changing coral associations and potential molluscan habitats. The Coralliophila neritoidea- Barbatia foliata assemblage depends on the presence of Porites and shows a dominance of gastropods feeding on corals and of bivalves associated with living corals. The Chamoidea- Cerithium spp. assemblage on rock grounds is strongly dominated by encrusting bivalves. The Drupella cornus-Pteriidae assemblage occurs on Millepora- Acropora reef slopes and is strongly dominated by bivalves associated with living corals. The Barbatia setigera- Ctenoides annulata assemblage includes a broad variety of taxa, molluscan life habits and bottom types, but occurs mainly on faviid carpets and is transitional among the other three assemblages. A predicted degradation of coral coverage to rock bottoms due to increasing eutrophication and physical damage in the study area (Riegl and Piller 2000) will result in a loss of coral-associated molluscs in favor of bivalve crevice dwellers in dead coral heads and of encrusters on dead hard substrata.

Molluscan assemblages on coral reefs and associated hard substrata in the northern Red Sea

Science.gov (United States)

Zuschin, M.; Hohenegger, J.; Steininger, F.

2001-09-01

Information on spatial variability and distribution patterns of organisms in coral reef environments is necessary to evaluate the increasing anthropogenic disturbance of marine environments (Richmond 1993; Wilkinson 1993; Dayton 1994). Therefore different types of subtidal, reef-associated hard substrata (reef flats, reef slopes, coral carpets, coral patches, rock grounds), each with different coral associations, were investigated to determine the distribution pattern of molluscs and their life habits (feeding strategies and substrate relations). The molluscs were strongly dominated by taxa with distinct relations to corals, and five assemblages were differentiated. The Dendropoma maxima assemblage on reef flats is a discrete entity, strongly dominated by this encrusting and suspension-feeding gastropod. All other assemblages are arranged along a substrate gradient of changing coral associations and potential molluscan habitats. The Coralliophila neritoidea- Barbatia foliata assemblage depends on the presence of Porites and shows a dominance of gastropods feeding on corals and of bivalves associated with living corals. The Chamoidea- Cerithium spp. assemblage on rock grounds is strongly dominated by encrusting bivalves. The Drupella cornus-Pteriidae assemblage occurs on Millepora- Acropora reef slopes and is strongly dominated by bivalves associated with living corals. The Barbatia setigera- Ctenoides annulata assemblage includes a broad variety of taxa, molluscan life habits and bottom types, but occurs mainly on faviid carpets and is transitional among the other three assemblages. A predicted degradation of coral coverage to rock bottoms due to increasing eutrophication and physical damage in the study area (Riegl and Piller 2000) will result in a loss of coral-associated molluscs in favor of bivalve crevice dwellers in dead coral heads and of encrusters on dead hard substrata.

Length-weight relationship of Giant Oyster, Crassostrea gyphoides (Schlotheim)

Digital Repository Service at National Institute of Oceanography (India)

Chatterji, A.; Ansari, Z.A.; Ingole, B.S.; Parulekar, A.H.

Relationship between shell length and total weight, shell weight and meat weight of giant oyster, Crassostrea gryphoides revealed that the growth of these parameters is very fast and significant. It indicates the suitability of the species concerned...

Length-Weight relationships of mangrove oyster, Crassostrea gasar ...

African Journals Online (AJOL)

The length-weight relationships (LWRs) of mangrove oyster, Crassostrea gasar, cultured under continuous and periodic submergence in tidal ponds, for a period of seven months, February to August 2010 were determined. A total of 375 individuals each of pond A (continuous submergence) and B (periodic submergence) ...

Artificially evolved functional shell morphology of burrowing bivalves

DEFF Research Database (Denmark)

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

2014-01-01

dimensional (3D) objects, the first ever artificial evolution of a physical bivalve shell was performed. The result was a vertically flattened shell occupying only the top sediment layers. Insufficient control of the sediment was the major limitation of the setup and restricted the significance of the results......, there are almost no studies experimentally testing their dynamic properties. To investigate the functional morphology of the bivalve shell, we employed a synthetic methodology and built an experimental setup to simulate the burrowing process. Using an evolutionary algorithm and a printer that prints three...

Detecting the presence of infectious hepatitis A virus in molluscs positive to RT-nested-PCR

NARCIS (Netherlands)

Medici, de D.; Croci, L.; Pasquale, di S.; Fiore, A.; Toti, L.

2001-01-01

Aims: The objective of this study was to det. the presence of infectious hepatitis A virus (HAV) in molluscs naturally contaminated with viral HAV-RNA. Methods and Results: One hundred and forty-two mollusc samples were analyzed for the presence of viral HAV-RNA using RT-nested-PCR; pos. samples

Veda-scope: More comfortable than the bivalve speculum and cytologically equivalent.

Science.gov (United States)

Longmore, Peter G

2004-04-01

The aim of the present study was to confirm that the Veda-scope is equivalent to the bivalve speculum in the collection of endocervical cells, as confirmation of adequate cervical sampling for Pap smear testing. The study also aimed to assess the comfort level of the Veda-scope compared to the traditional bivalve speculum and the patient preference of the Veda-scope compared to the bivalve speculum. Multicentre, randomised, controlled crossover, cytologist blinded study. The total number of subjects enrolled in the study were 250. The number of evaluable subjects were 210. In primary efficacy analysis, no significant difference was seen between the presence or absence of endocervical cells in the smears using either the Veda-scope or the bivalve speculum. There was a high concordance level between the diagnosis assigned to each specimen of a paired sample, the diagnosis agreeing in 97.6% cases. The primary reason given by many women for avoidance of regular Pap smear examinations is the discomfort or pain experienced with sample collection with the bivalve speculum. In the present study, 92% of subjects indicated a preference for the Veda-scope for Pap smear collection, while only 8.4% preferred the bivalve speculum. Subject preference was also assessed with respect to how the subject rated the comfort level of her previous Pap smear. In subjects who rated their previous Pap smear as very comfortable or comfortable, 86% expressed a preference for the Veda-scope. This rose to 93% in subjects who rated their previous Pap smear as only tolerable. The results of the present study show that Pap smear collections with the Veda-scope are of equal quality to those collected with the bivalve speculum, with an equivalent diagnostic outcome. A very strong preference for the Veda-scope was shown by the women enrolled in the present study based on the comfort levels experienced with the two devices.

Review of intersex in gastropods and other molluscs

DEFF Research Database (Denmark)

Strand, Jakob

Various studies have demonstrated that the presence of imposex, i.e. an imposition of a penis and/or a vas deferens in addition to the normal reproductive tracts in females of gonochoristics prosobranch gastropod species, is a common phenomenon in the marine environment today. However, also other....... This includes examples like transformation of the reproductive and genital tracts in gastropods and cephalopods, spermatogenesis in the female ovary and oocyte development in male testis (ovo-testis).  ......Various studies have demonstrated that the presence of imposex, i.e. an imposition of a penis and/or a vas deferens in addition to the normal reproductive tracts in females of gonochoristics prosobranch gastropod species, is a common phenomenon in the marine environment today. However, also other...... signs of endocrine disruption causing sex reversal, characterized as intersex, have been reported for marine molluscs. Intersex can more generally be defined as disturbance of the phenotypic sex characters and different types of intersex have been recorded for both female and male molluscs...

First report of Perkinsus beihaiensis in Crassostrea madrasensis from the Indian subcontinent.

Science.gov (United States)

Sanil, N K; Suja, G; Lijo, J; Vijayan, K K

2012-04-26

Protozoan parasites of the genus Perkinsus are considered important pathogens responsible for mass mortalities in many wild and farmed bivalve populations. The present study was initiated to screen populations of the Indian edible oyster Crassostrea madrasensis, a promising candidate for aquaculture along the Indian coasts, for the presence of Perkinsus spp. The study reports the presence of P. beihaiensis for the first time in C. madrasensis populations from the Indian subcontinent and south Asia. Samples collected from the east and west coasts of India were subjected to Ray's fluid thioglycollate medium (RFTM) culture and histology which indicated the presence of Perkinsus spp. PCR screening of the tissues using specific primers amplified the product specific to the genus Perkinsus. The taxonomic affinities of the parasites were determined by sequencing both internal transcribed spacer (ITS) and actin genes followed by basic local alignment search tool (BLAST) analysis. Analysis based on the ITS sequences showed 98 to 100% identity to Perkinsus spp. (P. beihaiensis and Brazilian Perkinsus sp.). The pairwise genetic distance values and phylogenetic analysis confirmed that 2 of the present samples belonged to the P. beihaiensis clade while the other 4 showed close affinities with the Brazilian Perkinsus sp. clade. The genetic divergence data, close affinity with the Brazilian Perkinsus sp., and co-existence with P. beihaiensis in the same host species in the same habitat show that the remaining 4 samples exhibit some degree of variation from P. beihaiensis. As expected, the sequencing of actin genes did not show any divergence among the samples studied. They probably could be intraspecific variants of P. beihaiensis having a separate lineage in the process of evolution.

Evolution and functional analysis of the Pif97 gene of the Pacific oyster Crassostrea gigas

Directory of Open Access Journals (Sweden)

Xiaotong WANG, Xiaorui SONG, Tong WANG, Qihui ZHU, Guoying MIAO, Yuanxin CHEN, Xiaodong FANG, Huayong QUE, Li LI, Guofan ZHANG

2013-02-01

Full Text Available Mollusc shell matrix proteins (SMPs are important functional components embedded in the shell and play a role in shell formation. A SMP (Pif177 was identified previously from the nacreous layer of the Japanese pearl oyster Pinctada fucata, and its cleavage products (named pfPif97 and pfPif80 proteins were found to bind to the chitin framework and induce aragonite crystal formation and orient the c axis. In this study, a homologue of pfPif177 was cloned from the mantle of the Pacific oyster Crassostrea gigas, containing the homologue of pfPif97 only and not pfPif80. This finding hints at the large divergence in gene structure between the two species. This homologue (cgPif97 shares characteristics with pfPif97, and suggests that the biological functions of these two proteins may be similar. The expression pattern of cgPif97 in different tissues and development stages indicates that it may play an important role in shell formation of the adult oyster. The morphology of the inner shell surface was affected by injected siRNA of cgPif97 and the calcite laths of the shell became thinner and narrower when the siRNA dose increased, suggesting that the cgPif97 gene plays an important role in calcite shell formation in C. gigas. In conclusion, we found evidence that the Pif177 gene evolved very fast but still retains a similar function among species [Current Zoology 59 (1: 109–115, 2013].

Ancient DNA analysis identifies marine mollusc shells as new metagenomic archives of the past

DEFF Research Database (Denmark)

Der Sarkissian, Clio; Pichereau, Vianney; Dupont, Catherine

2017-01-01

Marine mollusc shells enclose a wealth of information on coastal organisms and their environment. Their life history traits as well as (palaeo-) environmental conditions, including temperature, food availability, salinity and pollution, can be traced through the analysis of their shell (micro...... extraction, high-throughput shotgun DNA sequencing and metagenomic analyses to marine mollusc shells spanning the last ~7,000 years. We report successful DNA extraction from shells, including a variety of ancient specimens, and find that DNA recovery is highly dependent on their biomineral structure......, carbonate layer preservation and disease state. We demonstrate positive taxonomic identification of mollusc species using a combination of mitochondrial DNA genomes, barcodes, genome-scale data and metagenomic approaches. We also find shell biominerals to contain a diversity of microbial DNA from the marine...

Crassostrea gigas OYSTERS SMOKING: THE HOT AND WITH LIQUID SMOKE DEFUMAÇÃO DE OSTRAS Crassostrea gigas: A QUENTE E COM FUMAÇA LÍQUIDA

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Maria Luiza de Rodrigues de Souza

2007-07-01

Full Text Available The present study had as objective evaluates two techniques of traditional smoking the hot and with use of the liquid smoke, tends as control the Pacific oysters Crassostrea gigas cooked. They were appraised the sensorial characteristics and revenue of the processing. The animals were distributed in three treatments and the experimental design was completely randomized, with nine repetitions. For the sensorial analysis 30 fitting room were used, where each one was considered a block. There was not significant difference among the independent of the applied technique smoky oysters (T1 = 8.42% and T2 = 7.61%, but they differed of the control (T3 = 16.25%.In agreement with the applied methodology and with the results obtained in the sensorial analysis, the smoke oysters (independent of the applied technique are products with great acceptability and increased your sensorial characteristics. KEY-WORDS: Crassostrea gigas, oysters, hot smoking, liquid smoke. valiaram-se duas técnicas de defumação – tradicional a quente e com utilização da fumaça líquida –, tendo testemunha o cozimento de ostras do Pacífico Crassostrea gigas. Para tanto, examinaram-se as características sensoriais e rendimento do processamento. Distribuíram-se animais aleatoriamente, em três tratamentos, com delineamento experimental inteiramente casualizado e nove repetições. Para a análise sensorial, empregaram-se trinta provadores, considerando-se cada um deles um bloco. Não houve diferença significativa de rendimento entre as ostras defumadas, independentemente da técnica aplicada (T1 = 8,42% e T2 = 7,61%, mas elas diferiram da testemunha (T3 = 16,25%. De acordo com a metodologia aplicada e com os resultados obtidos nas análises sensoriais, as ostras defumadas (independentemente da técnica aplicada constituíram os produtos com maior aceitabilidade e houve incremento de suas características sensoriais. PALAVRAS-CHAVES: Crassostrea gigas, defumação a

The isotopic biosignatures of photo- vs. thiotrophic bivalves: are they preserved in fossil shells?

Science.gov (United States)

Dreier, A; Loh, W; Blumenberg, M; Thiel, V; Hause-Reitner, D; Hoppert, M

2014-09-01

Symbiont-bearing and non-symbiotic marine bivalves were used as model organisms to establish biosignatures for the detection of distinctive symbioses in ancient bivalves. For this purpose, the isotopic composition of lipids (δ13C) and bulk organic shell matrix (δ13C, δ34S, δ15N) from shells of several thiotrophic, phototrophic, or non-symbiotic bivalves were compared (phototrophic: Fragum fragum, Fragum unedo, Tridacna maxima; thiotrophic: Codakia tigerina, Fimbria fimbriata, Anodontia sp.; non-symbiotic: Tapes dorsatus, Vasticardium vertebratum, Scutarcopagia sp.). ∆13C values of bulk organic shell matrices, most likely representing mainly original shell protein/chitin biomass, were depleted in thio- and phototrophic bivalves compared to non-symbiotic bivalves. As the bulk organic shell matrix also showed a major depletion of δ15N (down to -2.2 ‰) for thiotrophic bivalves, combined δ13C and δ15N values are useful to differentiate between thio-, phototrophic, and non-symbiotic lifestyles. However, the use of these isotopic signatures for the study of ancient bivalves is limited by the preservation of the bulk organic shell matrix in fossils. Substantial alteration was clearly shown by detailed microscopic analyses of fossil (late Pleistocene) T. maxima and Trachycardium lacunosum shell, demonstrating a severe loss of quantity and quality of bulk organic shell matrix with time. Likewise, the composition and δ13C-values of lipids from empty shells indicated that a large part of these compounds derived from prokaryotic decomposers. The use of lipids from ancient shells for the reconstruction of the bivalve's life style therefore appears to be restricted. © 2014 John Wiley & Sons Ltd.

Enterococcus spp. Resistant to Multiple Antimicrobial Drugs and Determination of Fecal Contamination Levels in Mangrove Oysters (Crassostrea rhizophorae

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Cynthia Annes Rubião

2017-08-01

Full Text Available ABSTRACT The aim of this study was to determine and compare the Most Probable Number (MPN of Total Coliforms (TC, Escherichia coli and Enterococcus spp. and to characterize the antimicrobial resistance profiles of Enterococcus spp. isolated from oysters collected in the Barra de Guaratiba Mangrove, Rio de Janeiro, Brazil. The enumeration of E. coli has been used to indicate fecal contamination and hygienic-sanitary conditions of bivalve molluscs. Enterococci are capable to transfer several antimicrobial resistance genes to pathogenic bacteria, including those from Gram-negative group. The oysters were bought from local fishermen and a total of 123 individuals were analyzed. The TC, E. coli and Enterococcus spp. MPN mean were 26,300/100 g, 3,260/100 g and 2,820/100 g, respectively. The only correlation found was between TC and E. coli. Two strains of Enterococcus spp. were resistant to three different antimicrobial categories, including a high level resistance to streptomycin. One strain presented intermediate resistance to vancomycin. The E. coli levels exceeded the limits established by international legislation. This microbiological contamination in oysters reflects the water pollution and indicates a probable contamination of other seafood species from this mangrove, which can represent a risk for consumers and a threat to the environment and public health.

Bioconcentration of trace metals by Saccostrea cucullata (von Born 1778) from Andaman waters

Digital Repository Service at National Institute of Oceanography (India)

Abhilash, K.R.; Gireeshkumar, T.R.; Venu, S.; Raveendran, T.V.

glomerata 97 - 900 4.4 - 380 x x x 5. Bhat et al., 1968 27 Crassostrea gryphoides 171 - 403 x x x x 6. Coombs, 1972 28 Ostrea edulis 1050 - 395 42 - 67 x x x 7. Pringle et al., 1968 29 Crassostrea virginica 180 - 1420 7 - 517 x x x 8. Mc Farren et... Oyster, Mar Poll Bull, 6 (1975) 72–73. 27 Bhat Y M, Sastry H, Shah S M & Krishnamurthy T M, Manganese and cobalt content of some marine bivalves from Bombay. Indian National Science Academy Proceeding, Biology, 34 (1968) 283–287. 28 Coombs T L...

Trace Fossil Evidence of Trematode-Bivalve Parasite-Host Interactions in Deep Time.

Science.gov (United States)

Huntley, John Warren; De Baets, Kenneth

2015-01-01

Parasitism is one of the most pervasive phenomena amongst modern eukaryotic life and yet, relative to other biotic interactions, almost nothing is known about its history in deep time. Digenean trematodes (Platyhelminthes) are complex life cycle parasites, which have practically no body fossil record, but induce the growth of characteristic malformations in the shells of their bivalve hosts. These malformations are readily preserved in the fossil record, but, until recently, have largely been overlooked by students of the fossil record. In this review, we present the various malformations induced by trematodes in bivalves, evaluate their distribution through deep time in the phylogenetic and ecological contexts of their bivalve hosts and explore how various taphonomic processes have likely biased our understanding of trematodes in deep time. Trematodes are known to negatively affect their bivalve hosts in a number of ways including castration, modifying growth rates, causing immobilization and, in some cases, altering host behaviour making the host more susceptible to their own predators. Digeneans are expected to be significant agents of natural selection. To that end, we discuss how bivalves may have adapted to their parasites via heterochrony and suggest a practical methodology for testing such hypotheses in deep time. Copyright © 2015 Elsevier Ltd. All rights reserved.

Shell biofilm-associated nitrous oxide production in marine molluscs

DEFF Research Database (Denmark)

Heisterkamp, I.M.; Schramm, Andreas; Larsen, Lone Heimann

2013-01-01

Emission of the greenhouse gas nitrous oxide (N2O) from freshwater and terrestrial invertebrates has exclusively been ascribed to N2O production by ingested denitrifying bacteria in the anoxic gut of the animals. Our study of marine molluscs now shows that also microbial biofilms on shell surfaces...... are important sites of N2O production. The shell biofilms of Mytilus edulis, Littorina littorea and Hinia reticulata contributed 18-94% to the total animal-associated N2O emission. Nitrification and denitrification were equally important sources of N2O in shell biofilms as revealed by 15N-stable isotope...... mollusc species. Ammonium excretion by the animals was found to be sufficient to sustain N2O production in the shell biofilm. Apparently, the animals provide a nutrient-enriched microenvironment that stimulates growth and N2O production of the shell biofilm. This animal-induced stimulation...

Benthic life on the tropical sandy shore: Miramar beach a case study

Digital Repository Service at National Institute of Oceanography (India)

Ingole, B.S.

of shore-dwelling bivalve molluscs. The foot of intertidal and subtidal clams such as Mactra violacea and Meretrix spp. is relatively large and powerful. It can pull the shell below the sand surface very quickly symbolising the burrowing life style. Other...

Microplastics contamination in molluscs from the northern part of the Persian Gulf.

Science.gov (United States)

Naji, Abolfazl; Nuri, Marzieh; Vethaak, A Dick

2018-04-01

Microplastics (MPs) are well-known emerging contaminants in the marine environment. A key route by which MPs can directly affect marine life is through ingestion. The objective of the present study was to evaluate the occurrence of MPs in marine life and seafood for human consumption in the Persian Gulf. We conducted a whole body analysis of MP (between 10 and 5000 μm in diameter) abundance in five species of molluscs with different feeding strategies, including both gastropods and bivalves from the littoral zone of the Iranian coast of the Persian Gulf. The mean number of total encountered MPs in all species ranged from 0.2 to 21.0 particles per g of soft tissue (wet weight) and from 3.7 to 17.7 particles per individual. Overall, microfibres followed by fragments were the most common type of MP isolated in each species (respectively > 50% and ≈26%). Film (≈14%) and pellets (≈2%) were less commonly observed. The observed MPs were classified into three size groups (ca. 10-25 μm, 25-250 μm and 250-5000 μm), and 37-58% of MPs fell into the smallest size group. Fourier transform infrared (FT-IR) analysis confirmed the presence of polyethylene (PE), polyethylene terephthalate (PET), and nylon (PA). Our results indicated that molluscan shellfish from the Persian Gulf contain MPs, with higher concentrations in a predatory species, suggesting trophic transfer of MPs in the food web. The consumption of edible species may be a source of human microplastic intake. We compared our results with those previously reported for other regions of the world and identified the need for further studies in the Persian Gulf. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Bivalve Production Chain in Santa Catarina, Brazil, and its Management and Operational Limitations

OpenAIRE

Gallon, Alessandra Vasconcelos; Universidade Federal do Ceará (UFC); Nascimento, Cristiano; Universidade Federal do Paraná - UFPR; Pfitscher, Elisete Dahmer; Universidade Federal de Santa Catarina

2011-01-01

Bivalve farming (mussels and oysters), a major component in the socio-economic development of the state of Santa Catarina, Brazil, combines the activities of public and private agencies in fish farming. Current analysis deals with the management and the operational limitations of the local bivalve production chain. Current exploratory research, undertaken by direct observations and the literature on the subject, employs data quality. Results show that the bivalve production chain, comprising ...

Predicting the effects of ocean acidification on predator-prey interactions: a conceptual framework based on coastal molluscs.

Science.gov (United States)

Kroeker, Kristy J; Sanford, Eric; Jellison, Brittany M; Gaylord, Brian

2014-06-01

The influence of environmental change on species interactions will affect population dynamics and community structure in the future, but our current understanding of the outcomes of species interactions in a high-CO2 world is limited. Here, we draw upon emerging experimental research examining the effects of ocean acidification on coastal molluscs to provide hypotheses of the potential impacts of high-CO2 on predator-prey interactions. Coastal molluscs, such as oysters, mussels, and snails, allocate energy among defenses, growth, and reproduction. Ocean acidification increases the energetic costs of physiological processes such as acid-base regulation and calcification. Impacted molluscs can display complex and divergent patterns of energy allocation to defenses and growth that may influence predator-prey interactions; these include changes in shell properties, body size, tissue mass, immune function, or reproductive output. Ocean acidification has also been shown to induce complex changes in chemoreception, behavior, and inducible defenses, including altered cue detection and predator avoidance behaviors. Each of these responses may ultimately alter the susceptibility of coastal molluscs to predation through effects on predator handling time, satiation, and search time. While many of these effects may manifest as increases in per capita predation rates on coastal molluscs, the ultimate outcome of predator-prey interactions will also depend on how ocean acidification affects the specified predators, which also exhibit complex responses to ocean acidification. Changes in predator-prey interactions could have profound and unexplored consequences for the population dynamics of coastal molluscs in a high-CO2 ocean. © 2014 Marine Biological Laboratory.

Predation and habitat modification synergistically interact to control bivalve recruitment on intertidal mudflats

NARCIS (Netherlands)

van der Heide, T.; Tielens, E.; van der Zee, E.M.; Weerman, E.J.; Holthuijsen, S.; Eriksson, B.K.; Piersma, T.; van de Koppel, J.; Olff, H.

2014-01-01

Bivalves are key components of coastal ecosystems because they link pelagic and benthic food webs, and shape the landscape through habitat modification. Nevertheless, many bivalve stocks have dramatically declined, and recruitment failure due to (anthropogenically-) increased predation by

Predation and habitat modification synergistically interact to control bivalve recruitment on intertidal mudflats

NARCIS (Netherlands)

van der Heide, Tjisse; Tielens, Elske; van der Zee, Els; Weerman, Ellen J.; Holthuijsen, Sander; Eriksson, Britas Klemens; Piersma, Theun; van de Koppel, Johan; Olff, Han

Bivalves are key components of coastal ecosystems because they link pelagic and benthic food webs, and shape the landscape through habitat modification. Nevertheless, many bivalve stocks have dramatically declined, and recruitment failure due to (anthropogenically-) increased predation by

Gonad Transcriptome Analysis of the Pacific Oyster Crassostrea gigas Identifies Potential Genes Regulating the Sex Determination and Differentiation Process.

Science.gov (United States)

Yue, Chenyang; Li, Qi; Yu, Hong

2018-04-01

The Pacific oyster Crassostrea gigas is a commercially important bivalve in aquaculture worldwide. C. gigas has a fascinating sexual reproduction system consisting of dioecism, sex change, and occasional hermaphroditism, while knowledge of the molecular mechanisms of sex determination and differentiation is still limited. In this study, the transcriptomes of male and female gonads at different gametogenesis stages were characterized by RNA-seq. Hierarchical clustering based on genes differentially expressed revealed that 1269 genes were expressed specifically in female gonads and 817 genes were expressed increasingly over the course of spermatogenesis. Besides, we identified two and one gene modules related to female and male gonad development, respectively, using weighted gene correlation network analysis (WGCNA). Interestingly, GO and KEGG enrichment analysis showed that neurotransmitter-related terms were significantly enriched in genes related to ovary development, suggesting that the neurotransmitters were likely to regulate female sex differentiation. In addition, two hub genes related to testis development, lncRNA LOC105321313 and Cg-Sh3kbp1, and one hub gene related to ovary development, Cg-Malrd1-like, were firstly investigated. This study points out the role of neurotransmitter and non-coding RNA regulation during gonad development and produces lists of novel relevant candidate genes for further studies. All of these provided valuable information to understand the molecular mechanisms of C. gigas sex determination and differentiation.

Short-term fluctuations in bivalve larvae compared with some environmental factors in a coastal lagoon (South Portugal

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Luis M.Z. Chícaro

2000-12-01

Full Text Available In this study, short-term fluctuations in bivalve larvae were compared with some triggering factors for a period of sixteen months. Data on the abundance of planktonic larvae, collected two to three times a week were related to water temperature, salinity, wind velocity, tidal amplitude and chlorophyll a. Higher densities of planktonic bivalve larvae were caught between May and August, but intense fluctuations in abundance were observed. Planktonic bivalve larvae of eighteen taxa were identified. Larvae of Mytilus galloprovincialis, Cerastoderma edule, Ruditapes decussates and Venerupis spp. were the most abundant. The seasonal fluctuations of bivalve abundance seem to be controlled by temperature, the major factor in the timing of the reproduction of bivalves. Nevertheless, advection may be also a key factor during the planktonic life of bivalve species in coastal systems, such as the Ria Formosa.

Genomics study of the exposure effect of Gymnodinium catenatum, a paralyzing toxin producer, on Crassostrea gigas' defense system and detoxification genes.

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Norma García-Lagunas

Full Text Available BACKGROUND: Crassostrea gigas accumulates paralytic shellfish toxins (PST associated with red tide species as Gymnodinium catenatum. Previous studies demonstrated bivalves show variable feeding responses to toxic algae at physiological level; recently, only one study has reported biochemical changes in the transcript level of the genes involved in C. gigas stress response. PRINCIPAL FINDINGS: We found that 24 h feeding on toxic dinoflagellate cells (acute exposure induced a significant decrease in clearance rate and expression level changes of the genes involved in antioxidant defense (copper/zinc superoxide dismutase, Cu/Zn-SOD, cell detoxification (glutathione S-transferase, GST and cytochrome P450, CPY450, intermediate immune response activation (lipopolysaccharide and beta glucan binding protein, LGBP, and stress responses (glutamine synthetase, GS in Pacific oysters compared to the effects with the non-toxic microalga Isochrysis galbana. A sub-chronic exposure feeding on toxic dinoflagellate cells for seven and fourteen days (30×10³ cells mL⁻¹ showed higher gene expression levels. A significant increase was observed in Cu/Zn-SOD, GST, and LGBP at day 7 and a major increase in GS and CPY450 at day 14. We also observed that oysters fed only with G. catenatum (3×10³ cells mL⁻¹ produced a significant increase on the transcription level than in a mixed diet (3×10³ cells mL⁻¹ of G. catenatum+0.75×10⁶ cells mL⁻¹ I. galbana in all the analyzed genes. CONCLUSIONS: Our results provide gene expression data of PST producer dinoflagellate G. catenatum toxic effects on C. gigas, a commercially important bivalve. Over expressed genes indicate the activation of a potent protective mechanism, whose response depends on both cell concentration and exposure time against these toxic microalgae. Given the importance of dinoflagellate blooms in coastal environments, these results provide a more comprehensive overview of how oysters respond to

Genomics study of the exposure effect of Gymnodinium catenatum, a paralyzing toxin producer, on Crassostrea gigas' defense system and detoxification genes.

Science.gov (United States)

García-Lagunas, Norma; Romero-Geraldo, Reyna; Hernández-Saavedra, Norma Y

2013-01-01

Crassostrea gigas accumulates paralytic shellfish toxins (PST) associated with red tide species as Gymnodinium catenatum. Previous studies demonstrated bivalves show variable feeding responses to toxic algae at physiological level; recently, only one study has reported biochemical changes in the transcript level of the genes involved in C. gigas stress response. We found that 24 h feeding on toxic dinoflagellate cells (acute exposure) induced a significant decrease in clearance rate and expression level changes of the genes involved in antioxidant defense (copper/zinc superoxide dismutase, Cu/Zn-SOD), cell detoxification (glutathione S-transferase, GST and cytochrome P450, CPY450), intermediate immune response activation (lipopolysaccharide and beta glucan binding protein, LGBP), and stress responses (glutamine synthetase, GS) in Pacific oysters compared to the effects with the non-toxic microalga Isochrysis galbana. A sub-chronic exposure feeding on toxic dinoflagellate cells for seven and fourteen days (30×10³ cells mL⁻¹) showed higher gene expression levels. A significant increase was observed in Cu/Zn-SOD, GST, and LGBP at day 7 and a major increase in GS and CPY450 at day 14. We also observed that oysters fed only with G. catenatum (3×10³ cells mL⁻¹ produced a significant increase on the transcription level than in a mixed diet (3×10³ cells mL⁻¹ of G. catenatum+0.75×10⁶ cells mL⁻¹ I. galbana) in all the analyzed genes. Our results provide gene expression data of PST producer dinoflagellate G. catenatum toxic effects on C. gigas, a commercially important bivalve. Over expressed genes indicate the activation of a potent protective mechanism, whose response depends on both cell concentration and exposure time against these toxic microalgae. Given the importance of dinoflagellate blooms in coastal environments, these results provide a more comprehensive overview of how oysters respond to stress generated by toxic dinoflagellate exposure.

Padrões de abundância, riqueza e diversidade de moluscos bivalves na plataforma continental ao largo de Ubatuba, São Paulo, Brasil: uma comparação metodológica

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Soares-Gomes Abílio

2003-01-01

Full Text Available The diversity and richness patterns of bivalve molluscs were studied on the continental shelf of Ubatuba (23º38'S, 45º14'W and 23º25'S, 44º51'W between 15-120 metres depth. The samples were taken with a rectangular dredge and a beam trawl. The results showed higher values of richness, diversity and evenness for inner shelf (from coast to nearly 50 m depth and greater values of abundance for outer shelf (from 50 to around 120 m depth. This pattern might be due to the higher instability of the inner shelf, which is influenced by the seasonal intrusion of the South Atlantic Central Water (SACW and the occurrence of cold fronts. Sanders' rarefation curves, distribution and abundance curves and DIMO model were used and the results compared. The Qinghong's model proved to be a good tool for summarizes the results of diversity in a such plural account.

Sediment core fossils in ancient Lake Ohrid: testing for faunal change since the Last Interglacial

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C. Albrecht

2010-11-01

Full Text Available Ancient Lake Ohrid is probably of early Pleistocene or Pliocene origin and amongst the few lakes in the world harbouring an outstanding degree of endemic biodiversity. Although there is a long history of evolutionary research in Lake Ohrid, particularly on molluscs, a mollusc fossil record has been missing up to date. For the first time, gastropod and bivalve fossils are reported from the basal, calcareous part of a 2.6 m long sediment succession (core Co1200 from the north-eastern part of Lake Ohrid. Electron spin resonance (ESR dating of mollusc shells from the same stratigraphic level yielded an age of 130 ± 28 ka. Lithofacies III sediments, i.e. a stratigraphic subdivision comprising the basal succession of core Co1200 between 181.5–263 cm, appeared solid, greyish-white, and consisted almost entirely of silt-sized endogenic calcite (CaCO₃>70% and intact and broken mollusc shells. Here we compare the faunal composition of the thanatocoenosis with recent mollusc associations in Lake Ohrid. A total of 13 mollusc species (9 gastropod and 4 bivalve species could be identified within Lithofacies III sediments. The value of sediment core fossils for reconstructing palaeoenvironmental settings was evaluated and the agreement between sediment and palaeontological proxies was tested.

The study also aims at investigating major faunal changes since the Last Interglacial and searching for signs of extinction events.

The combined findings of the ecological study and the sediment characteristics suggest deposition in a shallow water environment during the Last Interglacial. The fossil fauna exclusively included species also found in the present fauna, i.e. no extinction events are evident for this site since the Last Interglacial. The thanatocoenosis showed the highest similarity with recent Intermediate Layer (5–25 m water depth mollusc assemblages. The demonstrated existence of a mollusc fossil record in Lake Ohrid

Bivalves: From individual to population modelling

NARCIS (Netherlands)

Saraiva, S.; van der Meer, J.; Kooijman, S.A.L.M.

2014-01-01

An individual based population model for bivalves was designed, built and tested in a 0D approach, to simulate the population dynamics of a mussel bed located in an intertidal area. The processes at the individual level were simulated following the dynamic energy budget theory, whereas initial egg

Development of human impact on suspension-feeding bivalves in coastal soft-bottom ecosystems

NARCIS (Netherlands)

Wolff, Wim J.; Dame, RF; Olenin, S

2005-01-01

Suspension-feeding bivalves often may occur in large concentrations ('beds') on tidal flats. This makes them attractive for human consumers and the archaeological record shows collection of bivalves by coastal populations already tens of thousands of years ago. In modem time human interference with

Histological techniques for marine bivalve mollusks and crustaceans, 2nd edition

OpenAIRE

Howard, Dorothy W.; Lewis, Earl J.; Keller, B. Jane; Smith, Cecelia S.

2004-01-01

Investigators at the Cooperative Oxford Laboratory (COL) diagnose and study crustaceans, mollusks, finfish, and a variety of other marine and estuarine invertebrates to assess animal health. This edition updates the Histological Techniques for Marine Bivalve Mollusks manual by Howard and Smith (1983) with additional chapters on molluscan and crustacean techniques. The new edition is intended to serve as a guide for histological processing of shellfish, principally bivalve mollusks and crustac...

Markers associated with disease resistance in Eastern oysters, Crassostrea virginica

Science.gov (United States)

Eastern oyster, Crassostrea viginica, is an economically important aquaculture species in the USA, but production has been impacted by diseases such as dermo and MSX. Efforts have been put into the development of disease-resistant oyster lines using selective breeding techniques. However, these met...

The impact of small benthic passive suspension feeders in shallow marine ecosystems: the hydroids as an example

NARCIS (Netherlands)

Gili, J.-M.; Alvà, V.; Coma, R.; Orejas, C.; Pagès, F.; Ribes, M.; Zabala, M.; Arntz, W.; Bouillon, J.; Boero, F.; Hughes, R.G.

1998-01-01

Benthic suspension feeders are abundant in littoral and shallow sub-littoral ecosystems, where they feed on the plankton and on organic matter suspended in the water column. Recent studies indicate that active suspension feeders with powerful water filtration mechanisms (e.g., bivalve molluscs) may

Experimental effects of immersion time and water temperature on body condition, burying depth and timing of spawning of the tellinid bivalve Macoma balthica

Science.gov (United States)

de Goeij, Petra; Honkoop, Pieter J.

2003-03-01

The burying depth of many bivalve molluscs on intertidal mudflats varies throughout the year and differs between places. Many factors are known to influence burying depth on a seasonal or spatial scale, with temperature and tidal regime probably being very important. Burying depth, body condition and gonadal development of Macoma balthica were followed throughout winter and spring in an experiment in which water temperature and immersion time were manipulated. Unexpectedly, relative water temperature, in contrast to the prediction, did not generally affect body condition or burying depth. This was probably a consequence of the exceptionally overall low water temperatures during the experimental winter. Differences in temperature did, however, result in different timing of spawning: M. balthica spawned earlier at higher spring temperatures. Longer immersion times led to higher body condition only late in spring, but led to deeper burying throughout almost the whole period. There was no effect of immersion time on the timing of spawning. We conclude that a longer immersion time leads to deeper burying, independent of body condition. We also conclude that burying behaviour of M. balthica is not determined by the moment of spawning.

Vodní měkkýši bývalého lomu Chabařovice v severních Čechách

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Luboš Beran

2010-11-01

Full Text Available This paper completes the knowledge of aquatic molluscs of a former coal quarry Chabařovice near Ústí nad Labem in Northern Bohemia. This quarry was opened in 1977 and 20 years later the mining was finished. A part of the coal quarry was flooded and new water reservoir Milada originated in the area of 250 ha with max. depth 24,7 m and this water reservoir is the biggest aquatic habitat in this area. Other four smaller water reservoirs, numerous drainage canals and small wetlands were built and aquatic molluscs of these sites were studied in 2010. Altogether, 16 species of aquatic molluscs (12 gastropods, 4 bivalves were found at 41 sites. Drainage canals, new brooks and small new wetlands are inhabited by poor aquatic malacofauna which contains often only one or two widespread species – Galba truncatula and Radix auricularia. Bivalve Pisidium casertanum was found only at three sites. Similar situation is in the case of water reservoirs Rabenov and Roudníky. Only artifical water reservoir Milada and smaller water reservoir close to this lake are inhabited by rich aquatic malacofauna containing 14 respectively 6 species. Molluscs were studied also in the past before opening the quarry and the actual malacofauna is richer probably due to the existence of more aquatic habitats. Three non-native species were found and the occurrence of other non native species is expected in the future as well as changes in autochtonous malacofauna.

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

Science.gov (United States)

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

2017-03-01

Marine habitat function has been typically investigated in terms of biogeochemical regulation but rarely in terms of population renewal, which is mainly controlled by recruitment dynamics. The recruitment phase is crucial for organisms with a bentho-pelagic life cycle, such as bivalves, and it regulates the population renewal success. This study provides new insight on the role of temperate benthic habitats on bivalve recruitment, as a function of nursery areas. Six dominant benthic habitats of the Chausey archipelago (Normandy, France) were studied. In each habitat, bivalve recruit assemblages were described at the end of two reproductive seasons. Furthermore, Ostrea edulis juveniles were immerged on each habitat during two months to compare growth performances and feeding status, estimated by fatty acid composition. Recruit assemblages differ from each habitat according to sediment grain-size composition and bathymetrical levels. Subtidal habitats, and especially Crepidula fornicata banks and Glycymeris glycymeris coarse sands, supported the highest species abundance and richness of recruits. All O. edulis juveniles fed on the same trophic resources but digestive glands of juveniles from C. fornicata banks were more concentrated in total fatty acids than those from subtidal G. glycymeris coarse sands and maerl banks. Our results depict the key role of subtidal and structured habitats, composed of ecosystem engineers, in enhancing bivalve recruitment and extending the bivalve population renewal. This study suggests that the crucial role of these habitats as bivalve nurseries must be integrated in management perspectives. 2-column fitting image. 1-column fitting image.

Large-Scale Trade in Legally Protected Marine Mollusc Shells from Java and Bali, Indonesia.

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Vincent Nijman

Full Text Available Tropical marine molluscs are traded globally. Larger species with slow life histories are under threat from over-exploitation. We report on the trade in protected marine mollusc shells in and from Java and Bali, Indonesia. Since 1987 twelve species of marine molluscs are protected under Indonesian law to shield them from overexploitation. Despite this protection they are traded openly in large volumes.We collected data on species composition, origins, volumes and prices at two large open markets (2013, collected data from wholesale traders (2013, and compiled seizure data by the Indonesian authorities (2008-2013. All twelve protected species were observed in trade. Smaller species were traded for 32,000 shells valued at USD500,000, chambered nautilus (Nautilus pompilius (>3,000 shells, USD60,000 and giant clams (Tridacna spp. (>2,000 shells, USD45,000 were traded in largest volumes. Two-thirds of this trade was destined for international markets, including in the USA and Asia-Pacific region.We demonstrated that the trade in protected marine mollusc shells in Indonesia is not controlled nor monitored, that it involves large volumes, and that networks of shell collectors, traders, middlemen and exporters span the globe. This impedes protection of these species on the ground and calls into question the effectiveness of protected species management in Indonesia; solutions are unlikely to be found only in Indonesia and must involve the cooperation of importing countries.

Effect of linear alkylbenzene mixtures and sanitary sewage in biochemical and molecular responses in pacific oyster Crassostrea gigas.

Science.gov (United States)

Flores-Nunes, Fabrício; Mattos, Jacó J; Zacchi, Flávia L; Serrano, Miguel A S; Piazza, Clei E; Sasaki, Silvio T; Taniguchi, Satie; Bicego, Márcia C; Melo, Cláudio M R; Bainy, Afonso C D

2015-11-01

Urban effluents are rich in nutrients, organic matter, pharmaceuticals and personal care products (PPCPs), pesticides, hydrocarbons, surfactants, and others. Previous studies have shown that oysters Crassostrea gigas accumulate significant levels of linear alkylbenzenes (LABs) in sanitary sewage contaminated sites, but there is little information about its toxicological effects in marine bivalves. The aim of this study was to analyze the transcription of genes in two tissues of C. gigas exposed for 12, 24, and 36 h to LABs or sanitary sewage. Likewise, the activity of antioxidant and biotransformation enzymes was measured in oysters exposed for 36 h in all groups. Oysters exposed to LABs and oysters exposed to sanitary sewage showed different patterns of transcriptional responses. LAB-exposed oysters showed lower level of biological responses than the oysters exposed to sanitary sewage. Despite the ability of the oyster C. gigas to accumulate LABs (28-fold), the data indicate that these contaminants are not the cause for the transcriptional responses observed in oysters exposed to sanitary sewage. Possibly, the biological changes observed in the sanitary sewage-exposed oysters are associated with the presence of other contaminants, which might have caused synergistic, additive, or antagonistic effects. The results show that FABP-like and GST-ω-like messenger RNAs (mRNAs) have a rapid response in tissues of oyster C. gigas exposed to sanitary sewage, suggesting a possible protective response and a role in maintaining homeostasis of these organisms.

Covarying Shell Growth Parameters and the Regulation of Shell Shape in Marine Bivalves: A Case Study on Tellinoidea

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Jean Béguinot

2014-01-01

Full Text Available Specific parameters characterising shell shape may arguably have a significant role in the adaptation of bivalve molluscs to their particular environments. Yet, such functionally relevant shape parameters (shell outline elongation, dissymmetry, and ventral convexity are not those parameters that the animal may directly control. Rather than shell shape, the animal regulates shell growth. Accordingly, an alternative, growth-based description of shell-shape is best fitted to understand how the animal may control the achieved shell shape. The key point is, in practice, to bring out the link between those two alternative modes of shell-shape descriptions, that is, to derive the set of equations which connects the growth-based shell-shape parameters to the functionally relevant shell-shape parameters. Thus, a preliminary object of this note is to derive this set of equations as a tool for further investigations. A second object of this work is to provide an illustrative example of implementation of this tool. I report on an unexpected negative covariance between growth-based parameters and show how this covariance results in a severe limitation of the range of interspecific variability of the degree of ventral convexity of the shell outline within the superfamily Tellinoidea. Hypotheses are proposed regarding the constraints possibly at the origin of this limitation of interspecific variability.

Infectious diseases in oyster aquaculture require a new integrated approach.

Science.gov (United States)

Pernet, Fabrice; Lupo, Coralie; Bacher, Cédric; Whittington, Richard J

2016-03-05

Emerging diseases pose a recurrent threat to bivalve aquaculture. Recently, massive mortality events in the Pacific oyster Crassostrea gigas associated with the detection of a microvariant of the ostreid herpesvirus 1 (OsHV-1µVar) have been reported in Europe, Australia and New Zealand. Although the spread of disease is often viewed as a governance failure, we suggest that the development of protective measures for bivalve farming is presently held back by the lack of key scientific knowledge. In this paper, we explore the case for an integrated approach to study the management of bivalve disease, using OsHV-1 as a case study. Reconsidering the key issues by incorporating multidisciplinary science could provide a holistic understanding of OsHV-1 and increase the benefit of research to policymakers. © 2016 The Author(s).

Dioxin-like chemicals in bivalves and sediment collected from around Australia

Energy Technology Data Exchange (ETDEWEB)

Mueller, J.F.; Muller, R.; Goudkamp, K. [EnTox, The University of Queensland, Brisbane (AU)] (and others)

2004-09-15

The aquatic environment is a significant sink for persistent organic pollutants including dioxin-like chemicals. Besides continuous investigations into sources of higher chlorinated PCDD that have initially been found in soils, and later in dugong and sediments little is known about the levels of dioxin-like chemicals in Australia's aquatic environment. In 2002 the National Dioxin Program (NDP) was commissioned by the Department of Environment and Heritage, Australia. One focus of the NDP was to evaluate background levels of dioxin-like chemicals in Australia's environment. One component of the 'Environmental Levels' project aimed to identify dioxinlike chemicals in the aquatic environment including bivalves collected in both marine, estuarine and freshwater systems. Here we report results from the NDP aquatic study with a particular emphasis on the levels of dioxin-like chemicals in bivalves and sediments respectively in areas from where the bivalves were collected.

Spatial genetic features of eastern oysters (Crassostrea virginica Gmelin) in the Gulf of Mexico: northward movement of a secondary contact zone.

Science.gov (United States)

Anderson, Joel D; Karel, William J; Mace, Christopher E; Bartram, Brian L; Hare, Matthew P

2014-05-01

The eastern oyster (Crassostrea virginica Gmelin) is an economically and ecologically valuable marine bivalve occurring in the Gulf of Mexico. This study builds upon previous research that identified two divergent populations of eastern oysters in the western Gulf of Mexico. Allelic and genotypic patterns from 11 microsatellite markers were used to assess genetic structure and migration between the previously described oyster populations in Texas. The main findings are as follows: (1) there are two distinct populations (F ST = 0.392, P turbidity and depth are not correlated with allele frequencies on reefs in the contact zone or when analyzed across Texas, and (4) there is little evidence of directional selection acting on the loci assayed here, although patterns at four markers suggested the influence of balancing selection based on outlier analyses. These results are consistent with long-term historical isolation between populations, followed by secondary contact. Recent hydrological changes in the area of secondary contact may be promoting migration in areas that were previously inhospitable to eastern oysters, and observed differences in the timing of spawning may limit hybridization between populations. Comparison of these findings with the results of an earlier study of oysters in Texas suggests that the secondary contact zone has shifted approximately 27 km north, in as little as a 23-year span.

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

Construction and evaluation of a high-density SNP array for the Pacific oyster (Crassostrea gigas.

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Haigang Qi

Full Text Available Single nucleotide polymorphisms (SNPs are widely used in genetics and genomics research. The Pacific oyster (Crassostrea gigas is an economically and ecologically important marine bivalve, and it possesses one of the highest levels of genomic DNA variation among animal species. Pacific oyster SNPs have been extensively investigated; however, the mechanisms by which these SNPs may be used in a high-throughput, transferable, and economical manner remain to be elucidated. Here, we constructed an oyster 190K SNP array using Affymetrix Axiom genotyping technology. We designed 190,420 SNPs on the chip; these SNPs were selected from 54 million SNPs identified through re-sequencing of 472 Pacific oysters collected in China, Japan, Korea, and Canada. Our genotyping results indicated that 133,984 (70.4% SNPs were polymorphic and successfully converted on the chip. The SNPs were distributed evenly throughout the oyster genome, located in 3,595 scaffolds with a length of ~509.4 million; the average interval spacing was 4,210 bp. In addition, 111,158 SNPs were distributed in 21,050 coding genes, with an average of 5.3 SNPs per gene. In comparison with genotypes obtained through re-sequencing, ~69% of the converted SNPs had a concordance rate of >0.971; the mean concordance rate was 0.966. Evaluation based on genotypes of full-sib family individuals revealed that the average genotyping accuracy rate was 0.975. Carrying 133 K polymorphic SNPs, our oyster 190K SNP array is the first commercially available high-density SNP chip for mollusks, with the highest throughput. It represents a valuable tool for oyster genome-wide association studies, fine linkage mapping, and population genetics.

Molecular taxonomy of cupped oysters (Crassostrea, Saccostrea, and Striostrea) in Thailand based on COI, 16S, and 18S rDNA polymorphism.

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Klinbunga, S; Khamnamtong, B; Puanglarp, N; Jarayabhand, P; Yoosukh, W; Menasveta, P

2005-01-01

Genetic diversity of oysters Crassostrea belcheri (Sowerby, 1871), C. iredalei (Faustino, 1932), Saccostrea cucullata (Born, 1778), S. forskali (Gmelin, 1791), and Striostrea (Parastriostrea) mytiloides (Lamarck, 1819) (Ostreoida, Mollusca) was analyzed by polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) of 16S ribosomal DNA with AcsI, AluI, DdeI, DraI, RsaI, and TaqI, 18S ribosomal DNA with HinfI, and cytochrome oxidase subunit I with AcsI, DdeI and MboI. A total of 54 composite haplotypes were observed. Species-diagnostic markers were specifically found in C. belcheri, C. iredalei, and S. cucullata, but not in S. forskali and Striostrea mytiloides, which shared common composite haplotypes. Neighbor-joining trees constructed from genetic distances between pairs of composite haplotypes and species indicated large genetic differences between Crassostrea and Saccostrea (including Striostrea mytiloides), but closer relationships were observed within each genus. Four groups of unidentified oysters (Crassostrea sp. and Saccostrea sp. groups 1, 2, and 3) were also genetically analyzed. Fixed RFLP markers were found in Crassostrea sp. and Saccostrea sp. group 2, but not in Saccostrea sp. groups 1 and 3. Phylogenetic and genetic heterogeneity analyses indicated that Crassostrea sp. and Saccostrea sp. group 2 should be considered as newly unidentified oyster species in Thailand.

Prevalence of Perkinsus marinus (dermo), Haplosporidium nelsoni (MSX), and QPX in bivalves of Delaware's inland bays and quantitative, high-throughput diagnosis of dermo by QPCR.

Science.gov (United States)

Ulrich, Paul N; Ewart, John W; Marsh, Adam G

2007-01-01

Restoration of oyster reef habitat in the Inland Bays of Delaware was accompanied by an effort to detect and determine relative abundance of the bivalve pathogens Perkinsus marinus, Haplosporidium nelsoni, and QPX. Both the oyster Crassostrea virginica and the clam Mercenaria mercenaria were sampled from the bays. In addition, oysters were deployed at eight sites around the bays as sentinels for the three parasites. Perkinsus marinus prevalence was measured with a real-time, quantitative polymerase chain reaction (PCR) methodology that enabled high-throughput detection of as few as 31 copies of the ribosomal non-transcribed spacer region in 500 ng oyster DNA. The other pathogens were assayed using PCR with species-specific primers. Perkinsus marinus was identified in Indian River Bay at moderate prevalence ( approximately 40%) in both an artificial reef and a wild oyster population whereas sentinel oysters were PCR-negative after 3-months exposure during summer and early fall. Haplosporidium nelsoni was restricted to one oyster deployed in Little Assawoman Bay. QPX and P. marinus were not detected among wild clams. While oysters in these bays have historically been under the greatest threat by MSX, it is apparent that P. marinus currently poses a greater threat to recovery of oyster aquaculture in Delaware's Inland Bays.

IN VITRO KILLING OF PERKINSUS MARINUS BY HEMOCYTES OF OYSTERS CRASSOSTREA VIRGINICA

Science.gov (United States)

A colorimetric microbicidal assay was adapted, optimized and applied in experiments to characterize the in vitro capacity of eastern oyster (Crassostrea virginica) hemocytes to kill cultured isolates of Perkinsus marinus, a protozoan parasite causing a highly destructive disease...

Mollusc diversity associated with the non-indigenous macroalga Asparagopsis armata Harvey, 1855 along the Atlantic coast of the Iberian Peninsula.

Science.gov (United States)

Rubal, Marcos; Costa-Garcia, Ricardo; Besteiro, Celia; Sousa-Pinto, Isabel; Veiga, Puri

2018-05-01

The aims of this study were to explore mollusc assemblages associated with the non-indigenous macroalga Asparagopsis armata, to compare them with those on other macroalgae at the study region and to explore potential differences on mollusc assemblages between two regions in the Atlantic coast of the Iberian Peninsula, where A. armata is present. To achieve this, at each region, four intertidal shores were sampled. Twenty-nine mollusc species were reported and thus, A. armata harboured similar or higher diversity than other annual macroalgae in this area. When compared with perennial macroalgae, results depend on the species and studied area. Moreover, significant differences in structure of mollusc assemblages between the two studied regions were found. However, these were due to differences in the relative abundance of species rather than the presence of exclusive species at each region. Copyright © 2018 Elsevier Ltd. All rights reserved.

Linking changes in subcellular cadmium distribution to growth and mortality rates in transplanted freshwater bivalves (Pyganodon grandis)

International Nuclear Information System (INIS)

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

2006-01-01

Relationships between Cd accumulation and subcellular distribution, and growth and mortality rates were examined in the freshwater bivalve Pyganodon grandis in a transplant experiment. Organisms were transferred from a clean lacustrine site to four lakes situated along a Cd concentration gradient in the mining region of Rouyn-Noranda. The bivalves were maintained in open enclosures placed in the bottom sediments of the littoral zone of all five lakes for 400 days. At the end of the experiment, metallothionein (MT) was measured in the bivalve gills with a Hg-saturation assay and Cd partitioning among the various cytosolic protein pools was determined by size-exclusion chromatography. Marked differences were observed among the five sites: the range in calculated free-cadmium ion concentrations in water overlying the sediments was 35-fold whereas Cd concentrations in the gill cytosol of the transplanted bivalves varied three-fold. In the transplanted bivalves, the distribution of gill Cd among the various cytosolic complexes also varied significantly among sites. For bivalves transplanted to the three most contaminated sites, Cd concentrations in the high molecular weight pool (HMW > 25 kDa) were significantly higher than the baseline levels determined from bivalves caged at the reference site; a similar trend was seen for Cd concentrations in the metallothionein pool (Cd-MT). For bivalves transferred to two of the high contamination sites, proportionately less of the gill cytosolic Cd was sequestered (i.e. detoxified) by MT-like proteins. Reductions in survival were also observed at these two sites, and these elevated mortalities, in turn, were consistent with the absence of indigenous bivalve populations at these sites. This result is compatible with our recent work on P. grandis populations living in lakes of the Rouyn-Noranda area, in which we demonstrated that excessive accumulation of Cd in the HMW pool of the gill cytosol of the individual mollusks could be

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

environment and address economic considerations remains unanswered. This study provides the first overview of bivalve transfer activities for aquaculture purposes along the European Atlantic coast. Existing international and EU legislation is described, and potential weaknesses in the existing legislative......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...... frameworks are discussed. Recommendations for the development of integrated risk assessment methods are given. These may help to minimize the intrinsic threats of transfer activities in marine environments. The resulting impacts and effects of transfer activities of bivalves for aquaculture purpose...

Morphometric Studies on Anodonta Anatine Bivalve Population from the Dognecea Lake

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Marian Bura

2011-10-01

Full Text Available In the Dognecea Lake, near town Bocsa in Caras-Severin county a strong bivalve population has been discovered from the duck mussel specie (Anodonta anatina. Harvested individuals were transported to the Aquaculture laboratory where measurements and correct identification was made. This specie is considered endangered but in Banat area, especially in the Dognecea Lake it is well represented, having an ecological importance, but the bivalve can have an economical importance too, due to the high percentage of edible part of 56.5%.

Comunidad de moluscos asociados al mejillón verde Perna viridis (Mollusca: Bivalvia y sus relaciones tróficas en la costa norte de la Península de Araya, Estado Sucre, Venezuela

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Sioliz Villafranca

2006-12-01

communities associated with the green mussel Perna viridis (Mollusca: Bivalvia and their trophic relations on the north coast of Araya Peninsula, Sucre State, Venezuela. Perna viridis (Linné, 1758 is an Indo-Pacific bivalve of the intertidal zone that has invaded several ecosystems of the north coast of the Sucre State,Venezuela. Bimonthly samplings were carried out between October 1997 and August 1998 to study the mollusc communities associated with this species and their trophic relationships.Studies were conducted on a naturally-occuring bank of mussels two meters deep on the north coast of the peninsula of Araya (10°40’N -48°63’W. Sample organisms were collected withing areas defined by a quadrat of 0.25 m², and were identified to the species level using taxonomic keys that also included bibliographic identification of trophic level. A total of 1 235 individuals of P. viridis were collected, along with 3 163 specimens of associated species belonging to the phylum Mollusca, including bivalves, gastropods and polyplacophora.The associated mollusc organisms represented 50 species corresponding to 10 orders and 24 families, including 25 gastropod species, 22 bivalves and three polyplacophorans. With regard to trophic level 40% of the 50 species were suspensivores, 26% carnivores, 24% herbivores and the residual 10% represented two categories (suspensivore-detritivore, herbivore-suspensivore. Of the suspensivores the most common were: Perna perna, Musculus lateralis, Crassostrea rhizophorae and Ostrea equestris. The carnivore group was dominated by the three species of the Family Columbellidae, Mitrella lunata, Anachis obesa and Nitidella ocellata.The group of herbivores was dominated by two members of the family Fisurellidae, Diodora cayenensis and D. minuta.Two species of suspensivore-detritívore and three species of herbivore-suspensivore were also found in the genus Crepidula. The high percentage of suspensivores was thought indicative, inside this ecosystem, that

Exploring Proteomic Variation in Pacific Oysters (Crassostrea gigas)

OpenAIRE

Venkataraman, Yaamini

2017-01-01

150 sibling Pacific oysters (Crassostrea gigas) were outplanted at five different sites around Puget Sound. Oysters were placed in exclusion cages either inside or outside of eelgrass beds. After a month of environmental exposure, gill tissue samples were collected for proteomic analyses. Initial DIA mass spectrometry methods on a subset of oysters (one per site and eelgrass condition, 10 total) provide data for upwards of 6,000 proteins. A subset of stress-related proteins reveal site-specif...

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

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José Carlos Martins

2014-01-01

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

The use of bivalves as rapid, real-time indicators of aquatic pollution

International Nuclear Information System (INIS)

Markich, S.J.

1995-01-01

The ability of bivalves to filter large volumes of water on a daily basis, combined with the relatively high permeability of their cell membranes, make them valuable organisms to use in the contemporary detection of pollution. Bivalves are well known to respond to chemical contaminants by isolating their soft tissues from the aquatic medium by valve closure. The sensory acuity (via specialized sensory regions including the osphradium) and associated repertoire of this behavioral response can be employed to assess subtle effects exerted by chemical contaminants, such as complex effluents, that may ultimately influence the survival of these organisms. As hazard assessment tools, behavioral studies reflect sublethal toxicity and often yield a highly sensitive estimate of the lowest observable effect concentration (LOEC). Moreover, valve movement behavior has been identified as one of the more sensitive biological early warning measures to a variety of aquatic contaminants, in comparison with those used in other aquatic animal phyla. Therefore, the valve movement behavior of both freshwater (Hyridella depressa, Velesunio angasi and V. ambiguus) and marine (Mytilus edulis) bivalves was continuously monitored, using an on-line computer based data acquisition system, during exposure to either trace metals (e.g. Cu, Cd, Mn and U) or complex effluents (ie treated sewage effluent and acid leachate derived from contaminated Sydney Harbour sediments), in the context of using the valve movement behavior of the bivalve species to indicate the biological significance of exposure to the above-mentioned pollutants. The results indicate that several components of the valve movement behavior of each bivalve provide quantifiable and ecologically interpretable sub-lethal endpoints for the rapid and sensitive evaluation of waters containing either complex effluents or elevated levels of trace metals

Concentration peculiarities of radionuclides by freshwater molluscs of Chernobyl NPP exclusion zone

International Nuclear Information System (INIS)

Gudkov, D.I.; Kuz'menko, M.I.; Nazarov, A.B.; Derevets, V.V.

2001-01-01

The results of radionuclides 90 Sr and 137 Cs content in molluscs tissue of water objects within Chernobyl NPP exclusion zone has been analysed. The age dynamics of radionuclides content in some species of Gastropoda was studied

Assessment of pollution of the Boca de Camichin Estuary in Nayarit (Mexico) and its influence on oxidative stress in Crassostrea corteziensis oysters.

Science.gov (United States)

Toledo-Ibarra, G A; Díaz Resendiz, K J G; Ventura-Ramón, G H; Romero-Bañuelos, C A; Medina-Díaz, I M; Rojas-García, A E; Vega-López, A; Girón-Pérez, M I

2016-10-01

Boca de Camichin Estuary is one of the main producers of Crassostrea corteziensis oysters in Mexico, but the presence of pollutants can affect oyster production. Molluscs produce reactive oxygen species (ROS) in response to changes in the environment and pollution. These ROS induce oxidative damage in biomolecules. The main objective of this study was to evaluate pollution in the estuary and the subsequent oxidative stress in C. corteziensis oysters during the 2010 production cycle. For this aim, we performed monthly samplings in the oyster farms from January to May. We took water samples to quantify polycyclic aromatic hydrocarbon (PAH) and metal content; also, we evaluated oxidative damage (lipoperoxidation, lipidic hydroperoxides, protein oxidation) and enzyme activity (CAT, SOD, GPx, GST and AChE) in oyster gills. The results show the presence of Cu, Fe, Mn, naphthalene, benz[a]anthracene, pyrene, benz[a]pyrene and benzo[k]fluoranthene. On the other hand, AChE activity was not inhibited, which suggests that organophosphorus pollutants or carbamates were absent. Regarding oxidative stress, oysters from the estuary had oxidative damage in lipids, not proteins, and altered antioxidant enzyme activity, when compared to control organisms. Interestingly, we did not observe any correlation between the pollutants and the oxidative stress parameters evaluated in this study. Thus, we cannot rule out that a synergistic effect between the environmental variables and the pollutants is causing the oxidative stress in these oysters. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of chronic exposure to ionising radiation in the Pacific oyster Crassostrea gigas

Energy Technology Data Exchange (ETDEWEB)

Fievet, B.; Devos, A.; Voiseux, C.; Leconte-Pradines, C. [Institut de Radioprotection et de Surete' Nucleaire (France); Dallas, L.; Jha, A. [University of Plymouth (United Kingdom)

2014-07-01

The Cotentin peninsula (Normandy, France) hosts nuclear industry facilities which operate with controlled discharges of radionuclides in the marine environment. Compared to natural radioactivity, the increase by artificial radionuclides is small but constant. As a consequence, marine species are chronically exposed to low additional doses of ionizing radiation (IR). The effects of chronic exposure to radionuclides were investigated in early stages of development of the Japanese oyster Crassostrea gigas. On the basis of literature, mollusks are expected to be particularly resistant to acute IR (UNSCEAR, 1996. Sources and effects of ionizing radiation. Report to the General Assembly, with Scientific Annex. 86 p). Two different chronic exposure conditions consisted in external ({sup 137}Cs) and internal ({sup 241}Am) irradiation for two weeks. Biological endpoints were analyzed in parallel at both the integrated (growth) and molecular (target stress gene expression) levels. To identify potential biological targets of IR, oysters were first exposed to very high dose rates and radionuclide activities with the perspective to reduce the levels and to derive dose-response curves. Although the initial exposure levels ({sup 137}Cs 30 000 μGy.h{sup -1}; {sup 241}Am 57 000 Bq.L{sup -1}) were many orders of magnitude higher than those encountered in the natural environment, no significant change in the measured parameters was observed. This result was surprising because data from the literature showed that exposure of mussel Mytilus edulis to {sup 3}H at lower doses rates (10-100 μGy.h{sup -1}) induced DNA damage in hemocytes (Jha et al., 2005. Impact of low doses of tritium on the marine mussel, Mytilus edulis: Genotoxic effects and tissue-specific bioconcentration. Mutation Research/Genetic Toxicology and Environmental Mutagenesis 586, 47-57). To understand this apparent discrepancy between those two filtering bivalves, a new experiment was performed to compare the response

Interspecific hybridization between Crassostrea angulata and C. ariakensis

Science.gov (United States)

Yao, Tuo; Zhang, Yuehuan; Yan, Xiwu; Wang, Zhaoping; Li, Dongchun; Su, Jiaqi; Yu, Ruihai

2015-08-01

Interspecific hybridization can generate heterosis, which is proven to be a useful tool in selective breeding programs for oyster culture. Crassostrea angulata and C. ariakensis are two important economic shellfish species in China. We conducted 2 × 2 reciprocal crosses to determine whether these two species can cross-fertilize and their hybrids can hatch, survive and perform heterosis. Fertilization was found symmetrical without delay. The rate of fertilization success of C. angulata ♀ × C. ariakensis ♂ was lower than that of C. ariakensis ♀ × C. angulata ♂, and the success rate of both hybridizations was lower than that of two intraspecific crosses each. During the planktonic period, survival rate of the progeny was lower in the hybrid crosses than in the intraspecific crosses. On day 360, mean shell height of the progeny of C. angulata ♀ × C. angulata ♂ was highest, which was followed by that of C. angulata ♀ × C. ariakensis ♂, C. ariakensis ♀ × C. ariakensis ♂ and C. ariakensis ♀ × C. angulata ♂ in a descending order. Morphology of adults produced by the hybrid crosses was similar to that of C. angulata. Both hybrids underwent normal gonad development and produced mature gametes in the mating season. This study provided new insights into the quantitative traits in interspecific crosses of Crassostrea species, thus being of guidance value for selective breeding of oyster.

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......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...... with the aim of producing food, not sequestering CO2 in their shells, therefore the main ecosystem good provided by bivalve aquaculture is meat production, and shells should be considered as by-products of this human activity. This reasoning is key to split the CO2 released due to respiration between meat...

Fauna of gastropod molluscs in the Curonian Lagoon littoral biotopes (Baltic Sea, Kaliningrad region, Russia

Directory of Open Access Journals (Sweden)

Dmitry Filippenko

2011-12-01

Full Text Available A survey of the gastropod mollusc fauna in the coastal waters of the southern part of the Curonian Lagoon (Kaliningrad region, Russia were carried out. Study revealed 34 aquatic gastropods representing 30% of Prosobranchia and 70% of Pulmonata. Obtained data showed higher mollusc diversity in the littoral biotopes in comparison with open areas of the Lagoon. The fauna is represented by a typical Central European species complex of freshwater gastropods. The reed zone along the coastline in the Lagoon functions as a barrier and provides shallow water habitats with slow moving and warmer water, where maximum gastropod species concentrate.

Immunological responses of the mangrove oysters Crassostrea gasar naturally infected by Perkinsus sp. in the Mamanguape Estuary, Paraíba state (Northeastern, Brazil).

Science.gov (United States)

Queiroga, Fernando Ramos; Marques-Santos, Luis Fernando; Hégaret, Hélène; Soudant, Philippe; Farias, Natanael Dantas; Schlindwein, Aline Daiane; Mirella da Silva, Patricia

2013-08-01

Perkinsus genus includes protozoan parasites of marine mollusks, especially bivalves. In the last four years, this parasite has been detected in mangrove oysters Crassostrea rhizophorae and Crassostrea gasar from the Northeastern region of Brazil. Hemocytes are the key cells of the oyster immune system, being responsible for a variety of cellular and humoral reactions, such as phagocytosis, encapsulation and the release of several effector molecules that control the invasion and proliferation of microorganisms. In Brazil, there is little information on perkinsosis and none on the immune responses of native oysters' species against Perkinsus spp. The objective of this study was to determine the effects of natural infection by Perkinsus sp. on the immunological parameters of mangrove oysters C. gasar cultured in the Mamanguape River Estuary (Paraíba, Brazil). Adults oysters (N = 40/month) were sampled in December 2011, March, May, August and October 2012. Gills were removed and used to determine the presence and intensity of the Perkinsus sp. infection, according to a scale of four levels (1-4), using the Ray's fluid thioglycollate medium assay. Immunological parameters were measured in hemolymph samples by flow cytometry, including: total hemocyte count (THC), differential hemocyte count (DHC), cell mortality, phagocytic capacity, and production of Reactive Oxygen Species (ROS). The plasma was used to determine the hemagglutination activity. The results showed the occurrence of Perkinsus sp. with the highest mean prevalence (93.3%) seen so far in oyster populations in Brazil. Despite that, no oyster mortality was associated. In contrast, we observed an increase in hemocyte mortality and a suppression of two of the main defense mechanisms, phagocytosis and ROS production in infected oysters. The increase in the percentage of blast-like cells on the hemolymph, and the increase in THC in oysters heavily infected (at the maximum intensity, 4) suggest an induction of

Persistence of enteric viruses within oysters (Crassostrea virginica)

Science.gov (United States)

It is well known that water-borne enteric viruses are concentrated by bivalves. Why these viruses are selectively retained and remain infectious within shellfish tissues for extended periods is unknown. Our current hypothesis is that phagocytic hemocytes (blood cells) are a site of virus persiste...

Lower Oligocene bivalves of Ramanian Stage from Kachchh ...

Indian Academy of Sciences (India)

Sehe area of western Kachchh considered their. Bed Nos. 4 and 5 as .... with very thin population. The Bermoti stream ...... Recent; Indo–Pacific. Subgenus: .... Type species: Cardium discors Lamarck' 1805; T. Eocene–Miocene; Europe–Asia ..... Shuto Tsugio 1971 Neogene Bivalves from Panay Island, the. Philippines.

Eye structure and vision in the freshwater pulmonate mollusc Planorbarius corneus

NARCIS (Netherlands)

Zhukov, VV; Bobkova, MB; Vakolyuk, IA

2002-01-01

The structure of the mollusc Planorbarius corneus eye was studied using light and electron microscopy. The eye consists of the cornea, eye lens of non-spherical shape, and the vitreous body tightly bound to it, as well as of a monolayer non-inverted retina composed of photoreceptor and supporting

Transcriptomics Analysis of Crassostrea hongkongensis for the Discovery of Reproduction-Related Genes

Science.gov (United States)

Tong, Ying; Zhang, Yang; Huang, Jiaomei; Xiao, Shu; Zhang, Yuehuan; Li, Jun; Chen, Jinhui; Yu, Ziniu

2015-01-01

Background The reproductive mechanisms of mollusk species have been interesting targets in biological research because of the diverse reproductive strategies observed in this phylum. These species have also been studied for the development of fishery technologies in molluscan aquaculture. Although the molecular mechanisms underlying the reproductive process have been well studied in animal models, the relevant information from mollusks remains limited, particularly in species of great commercial interest. Crassostrea hongkongensis is the dominant oyster species that is distributed along the coast of the South China Sea and little genomic information on this species is available. Currently, high-throughput sequencing techniques have been widely used for investigating the basis of physiological processes and facilitating the establishment of adequate genetic selection programs. Results The C.hongkongensis transcriptome included a total of 1,595,855 reads, which were generated by 454 sequencing and were assembled into 41,472 contigs using de novo methods. Contigs were clustered into 33,920 isotigs and further grouped into 22,829 isogroups. Approximately 77.6% of the isogroups were successfully annotated by the Nr database. More than 1,910 genes were identified as being related to reproduction. Some key genes involved in germline development, sex determination and differentiation were identified for the first time in C.hongkongensis (nanos, piwi, ATRX, FoxL2, β-catenin, etc.). Gene expression analysis indicated that vasa, nanos, piwi, ATRX, FoxL2, β-catenin and SRD5A1 were highly or specifically expressed in C.hongkongensis gonads. Additionally, 94,056 single nucleotide polymorphisms (SNPs) and 1,699 simple sequence repeats (SSRs) were compiled. Conclusions Our study significantly increased C.hongkongensis genomic information based on transcriptomics analysis. The group of reproduction-related genes identified in the present study constitutes a new tool for research

Transcriptomics Analysis of Crassostrea hongkongensis for the Discovery of Reproduction-Related Genes.

Directory of Open Access Journals (Sweden)

Ying Tong

Full Text Available The reproductive mechanisms of mollusk species have been interesting targets in biological research because of the diverse reproductive strategies observed in this phylum. These species have also been studied for the development of fishery technologies in molluscan aquaculture. Although the molecular mechanisms underlying the reproductive process have been well studied in animal models, the relevant information from mollusks remains limited, particularly in species of great commercial interest. Crassostrea hongkongensis is the dominant oyster species that is distributed along the coast of the South China Sea and little genomic information on this species is available. Currently, high-throughput sequencing techniques have been widely used for investigating the basis of physiological processes and facilitating the establishment of adequate genetic selection programs.The C.hongkongensis transcriptome included a total of 1,595,855 reads, which were generated by 454 sequencing and were assembled into 41,472 contigs using de novo methods. Contigs were clustered into 33,920 isotigs and further grouped into 22,829 isogroups. Approximately 77.6% of the isogroups were successfully annotated by the Nr database. More than 1,910 genes were identified as being related to reproduction. Some key genes involved in germline development, sex determination and differentiation were identified for the first time in C.hongkongensis (nanos, piwi, ATRX, FoxL2, β-catenin, etc.. Gene expression analysis indicated that vasa, nanos, piwi, ATRX, FoxL2, β-catenin and SRD5A1 were highly or specifically expressed in C.hongkongensis gonads. Additionally, 94,056 single nucleotide polymorphisms (SNPs and 1,699 simple sequence repeats (SSRs were compiled.Our study significantly increased C.hongkongensis genomic information based on transcriptomics analysis. The group of reproduction-related genes identified in the present study constitutes a new tool for research on bivalve

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

Science.gov (United States)

2011-10-20

... transmission of norovirus from infected or ill food workers in food manufacturing or retail establishments to... Molluscan Shellfish Contamination Levels During Food Preparation and Bivalve Molluscan Shellfish Consumption... and other factors influencing bivalve molluscan shellfish contamination levels during food preparation...

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

Science.gov (United States)

Wang, Sikai; Jin, Binsong; Qin, Haiming; Sheng, Qiang; Wu, Jihua

2015-01-01

Benthic bivalves are important links between primary production and consumers, and are essential intermediates in the flow of energy through estuarine systems. However, information on the diet of filter feeding bivalves in estuarine ecosystems is uncertain, as estuarine waters contain particulate matter from a range of sources and as bivalves are opportunistic feeders. We surveyed bivalves at different distances from the creek mouth at the Yangtze estuarine marsh in winter and summer, and analyzed trophic dynamics using stable isotope (SI) and fatty acid (FA) techniques. Different bivalve species had different spatial distributions in the estuary. Glauconome chinensis mainly occurred in marshes near the creek mouth, while Sinonovacula constricta preferred the creek. Differences were found in the diets of different species. S. constricta consumed more diatoms and bacteria than G. chinensis, while G. chinensis assimilated more macrophyte material. FA markers showed that plants contributed the most (38.86 ± 4.25%) to particular organic matter (POM) in summer, while diatoms contributed the most (12.68 ± 1.17%) during winter. Diatoms made the largest contribution to the diet of S. constricta in both summer (24.73 ± 0.44%) and winter (25.51 ± 0.59%), and plants contributed no more than 4%. This inconsistency indicates seasonal changes in food availability and the active feeding habits of the bivalve. Similar FA profiles for S. constricta indicated that the bivalve had a similar diet composition at different sites, while different δ13C results suggested the diet was derived from different carbon sources (C4 plant Spartina alterniflora and C3 plant Phragmites australis and Scirpus mariqueter) at different sites. Species-specific and temporal and/or spatial variability in bivalve feeding may affect their ecological functions in intertidal marshes, which should be considered in the study of food webs and material flows in estuarine ecosystems. PMID:26261984

Environmentally applications of invasive bivalves for water and wastewater decontamination.

Science.gov (United States)

Gomes, João; Matos, Ana; Quinta-Ferreira, Rosa M; Martins, Rui C

2018-07-15

The environmental and economic impact of invasive bivalve species implies the development of suitable pest management strategies. Chemical control is the most usual approach. However, the production of toxic intermediates as well as the unavoidable impact over non target biota is of special concern. Another approach consists on the physical removal of the animals from the invaded sites. The high biofiltration and bioaccumulation capacity of such animals make them interesting for the removal of contaminants from water and wastewater. In this context, environmental applications can be given for these pests encompassing nutrients removal for the recovery of eutrophic sites, water disinfection, organic and metal contaminants abatement. These approaches may be integrated with pest management where the physical removed animals from the invaded spots could be used for assembling biofilter for water and wastewater decontamination. However, some drawbacks must be addressed before proposing such alternative. In fact, the further spreading of the bivalves into non-invaded sites must be avoided. Moreover, some operational questions must be addressed such as the fate of contaminated animals after biofiltration. Bearing in mind the interesting results already available in this subject, this paper aims to critically overview literature regarding the environmental applications of invasive bivalves. Copyright © 2018 Elsevier B.V. All rights reserved.

Spermatozoan ultrastructure in the trigonioid bivalve Neotrigonia margaritacea Lamarck (Mollusca): Comparison with other bivalves, especially Trigonioida and Unionoida

Science.gov (United States)

Healy, J. M.

1996-06-01

Spermatozoa of the trigonioid bivalve Neotrigonia margaritacea (Lamarck) (Trigoniidae, Trigonioida) are examined ultrastructurally. A cluster of discoidal, proacrosomal vesicles (between 9 to 15 in number) constitutes the acrosomal complex at the nuclear apex. The nucleus is short (2.4 2.6 μm long, maximum diameter 2.2 μm), blunt-conical in shape, and exhibits irregular lacunae within its contents. Five or sometimes four round mitochondria are impressed into shallow depressions in the base of the nucleus as is a discrete centriolar fossa. The mitochondria surround two orthogonally arranged centrioles to form, collectively, the midpiece region. The distal centriole, anchored by nine satellite fibres to the plasma membrane, acts as a basal body to the sperm flagellum. The presence of numerous proacrosomal vesicles instead of a single, conical acrosomal vesicle sets Neotrigonia (and the Trigonioida) apart from other bivalves, with the exception of the Unionoida which are also known to exhibit this multivesicular condition. Spermatozoa of N. margaritacea are very similar to those of the related species Neotrigonia bednalli (Verco) with the exception that the proacrosomal vesicles of N. margaritacea are noticeably larger than those of N. bednalli.

Cadmium-handling strategies in two chronically exposed indigenous freshwater organisms-the yellow perch (Perca flavescens) and the floater mollusc (Pyganodon grandis)

International Nuclear Information System (INIS)

Campbell, Peter G.C.; Giguere, Anik; Bonneris, Emmanuelle; Hare, Landis

2005-01-01

Laboratory experiments on a variety of aquatic organisms suggest that metallothionein-like proteins (MT) play an important role in the regulation of essential metals, and in the sequestration and detoxification of non-essential metals (e.g., Cd). However, the importance of metallothionein production relative to alternative strategies of metal detoxification, and its effectiveness in metal detoxification, remain largely unexplored in field situations. In the present study we explored metal-handling strategies in an adult benthic bivalve (Pyganodon grandis) and in juvenile yellow perch (Perca flavescens), exposed to Cd in their natural habitat. The two biomonitor species were collected from lakes located along a Cd concentration gradient. Ambient dissolved Cd concentrations were determined by in situ dialysis as a measure of metal exposure. Sub-cellular Cd partitioning was determined in target tissues (bivalve gills and digestive gland; perch liver) by differential centrifugation, and metallothionein was measured independently by a mercury-saturation assay in the bivalve tissues. Malondialdehyde concentrations were measured as a potential indicator of oxidative stress. Ambient dissolved Cd concentrations ranged from 0.06 to 0.57 nM in the nine lakes from which bivalves were collected, and from max /[Cd] min ratios for the various tissues decreased in the order: bivalve gill Cd (28) > bivalve digestive gland Cd (18) > perch hepatic Cd (14). In the two lakes that were common to both the bivalve and perch studies, i.e. lakes Opasatica and Vaudray, accumulated Cd concentrations were consistently higher in the bivalve than in the perch. Cadmium-handling strategies were similar in the bivalve digestive gland and perch liver, in that Cd was mainly associated with the heat-stable protein (HSP) fraction. Furthermore, in these organs the contributions from the 'mitochondria' and 'lysosomes + microsomes' fractions were consistently higher than in the gill tissue. In the bivalve

[Distribution of acetylcholinesterase activity in the digestive system of the gastropod molluscs Littorina littorea and Achatina fulica].

Science.gov (United States)

Zaĭtseva, O V; Kuznetsova, T V

2008-01-01

With the use of the histochemical procedure for the demonstration of acetylcholinesterase (AchE) activity, the distribution cholinergic regulatory elements was studied in the esophagus, the pharynx, the stomach, the liver (the digestive gland) and the intestine in sea and terrestrial gastropod molluscs that differed in their general organization level, lifestyle, habitat and feeding type. In both molluscs, all the parts of the digestive tract contained the significant amount of intraepithelial AchE-positive cells of the open type, single subepithelial neurons and the nervous fibers localized among the muscle cells of the wall of the organs. The basal processes of the AchE-positive intraepithelial cells were shown to form the intraepithelial nerve plexus and to pass under the epithelium. The peculiarities and common principles in the distribution of the nervous elements detected, their possible function and the regulatory role in the digestion in gastropod molluscs and other animals are discussed.

Pacific oyster (Crassostrea gigas) hemocyte are not affected by a mixture of pesticides in short-term in vitro assays.

Science.gov (United States)

Moreau, Pierrick; Burgeot, Thierry; Renault, Tristan

2014-04-01

Pesticides are frequently detected in estuaries among the pollutants found in estuarine and coastal areas and may have major ecological consequences. They could endanger organism growth, reproduction, or survival. In the context of high-mortality outbreaks affecting Pacific oysters, Crassostrea gigas, in France since 2008, it appears of importance to determine the putative effects of pesticides on oyster susceptibility to infectious agents. Massive mortality outbreaks reported in this species, mainly in spring and summer, may suggest an important role played by the seasonal use of pesticides and freshwater input in estuarine areas where oyster farms are frequently located. To understand the impact of some pesticides detected in French waters, their effects on Pacific oyster hemocytes were studied through short-term in vitro experiments. Bivalve immunity is mainly supported by hemocytes eliminating pathogens by phagocytosis and producing compounds including lysosomal enzymes and antimicrobial molecules. In this study, oyster hemocytes were incubated with a mixture of 14 pesticides and metaldehyde alone, a molecule used to eliminate land mollusks. Hemocyte parameters including dead/alive cells, nonspecific esterase activities, intracytoplasmic calcium, lysosome number and activity, and phagocytosis were monitored by flow cytometry. No significant effect of pesticides tested at different concentrations was reported on oyster hemocytes maintained in vitro for short-term periods in the present study. It could be assumed that these oyster cells were resistant to pesticide exposure in tested conditions and developing in vivo assays appears as necessary to better understand the effects of pollutants on immune system in mollusks.

Thiol oxidation of hemolymph proteins in oysters Crassostrea brasiliana as markers of oxidative damage induced by urban sewage exposure.

Science.gov (United States)

Trevisan, Rafael; Flores-Nunes, Fabrício; Dolores, Euler S; Mattos, Jacó J; Piazza, Clei E; Sasaki, Sílvio T; Taniguchi, Satie; Montone, Rosalinda C; Bícego, Márcia C; Dos Reis, Isis M M; Zacchi, Flávia L; Othero, Bárbara N M; Bastolla, Camila L V; Mello, Danielle F; Fraga, Ana Paula M; Wendt, Nestor; Toledo-Silva, Guilherme; Razzera, Guilherme; Dafre, Alcir L; de Melo, Cláudio M R; Bianchini, Adalto; Marques, Maria R F; Bainy, Afonso C D

2017-07-01

Urban sewage is a concerning issue worldwide, threatening both wildlife and human health. The present study investigated protein oxidation in mangrove oysters (Crassostrea brasiliana) exposed to seawater from Balneário Camboriú, an important tourist destination in Brazil that is affected by urban sewage. Oysters were exposed for 24 h to seawater collected close to the Camboriú River (CAM1) or 1 km away (CAM2). Seawater from an aquaculture laboratory was used as a reference. Local sewage input was marked by higher levels of coliforms, nitrogen, and phosphorus in seawater, as well as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), linear alkylbenzenes (LABs), and fecal steroid in sediments at CAM1. Exposure of oysters to CAM1 caused marked bioaccumulation of LABs and decreased PAH and PCB concentrations after exposure to both CAM1 and CAM2. Protein thiol oxidation in gills, digestive gland, and hemolymph was evaluated. Lower levels of reduced protein thiols were detected in hemolymph from CAM1, and actin, segon, and dominin were identified as targets of protein thiol oxidation. Dominin susceptibility to oxidation was confirmed in vitro by exposure to peroxides and hypochlorous acid, and 2 cysteine residues were identified as potential sites of oxidation. Overall, these data indicate that urban sewage contamination in local waters has a toxic potential and that protein thiol oxidation in hemolymph could be a useful biomarker of oxidative stress in bivalves exposed to contaminants. Environ Toxicol Chem 2017;36:1833-1845. © 2016 SETAC. © 2016 SETAC.

Polarimetry of Pinctada fucata nacre indicates myostracal layer interrupts nacre structure.

Science.gov (United States)

Metzler, Rebecca A; Jones, Joshua A; D'Addario, Anthony J; Galvez, Enrique J

2017-02-01

The inner layer of many bivalve and gastropod molluscs consists of iridescent nacre, a material that is structured like a brick wall with bricks consisting of crystalline aragonite and mortar of organic molecules. Myostracal layers formed during shell growth at the point of muscle attachment to the shell can be found interspersed within the nacre structure. Little has been done to examine the effect the myostracal layer has on subsequent nacre structure. Here we present data on the structure of the myostracal and nacre layers from a bivalve mollusc, Pinctada fucata . Scanning electron microscope imaging shows the myostracal layer consists of regular crystalline blocks. The nacre before the layer consists of tablets approximately 400 nm thick, while after the myostracal layer the tablets are approximately 500 nm thick. A new technique, imaging polarimetry, indicates that the aragonite crystals within the nacre following the myostracal layer have greater orientation uniformity than before the myostracal layer. The results presented here suggest a possible interaction between the myostracal layer and subsequent shell growth.

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.

Geochemical aspects of Meretrix casta (bivalve) shells of Vellar ...

African Journals Online (AJOL)

SAM

2014-05-14

May 14, 2014 ... The bivalve mollusk, Meretrix casta shells are abundant in the Vellar estuary along the East .... the Shervarayan hills of Salem District in Tamil Nadu, India. .... coast of Peninsular Malaysia and its potential as biomaterial for use.

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

International Nuclear Information System (INIS)

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

2014-01-01

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

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

Sensory and Chemical Characteristics of Eastern Oysters(Crassostrea virginica)

OpenAIRE

Chen, Luman

2011-01-01

Eastern Oysters, or Crassostrea virginica, are an important dietary component in the Chesapeake region and have supported a major fishery in the Chesapeake for more than 100 years. Virginia oysters do not always receive attention in up-scale markets. It is possible that the lack of information on sensory characteristics of Chesapeake oysters may contribute to this problem. In order to differentiate Chesapeake oysters from other oysters, a descriptive sensory test (n=8) was conducted and chemi...

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

Science.gov (United States)

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

2013-05-01

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

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

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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.

Induction of gynogenetic haploidy in oyster Crassostrea gigas, using ultra violet irradiated sperms

Digital Repository Service at National Institute of Oceanography (India)

Goswami, U.

Eggs of Crassostrea gigas were fertilized with sperms exposed to different doses of UV irradiations by keeping a constant rate of 121.47 ergs. mm/2 sec/1 and changing the period of exposure from 4 to 90 sec. Samples of larvae were analysed...

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

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

2014-05-01

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

Ocean Acidification Has Multiple Modes of Action on Bivalve Larvae.

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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

Ocean Acidification Has Multiple Modes of Action on Bivalve Larvae.

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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

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

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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

Marine 14C reservoir ages for 19th century whales and molluscs from the North Atlantic

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Mangerud, Jan; Bondevik, Stein; Gulliksen, Steinar; Karin Hufthammer, Anne; Høisæter, Tore

2006-12-01

In order to compare radiocarbon dates on marine and terrestrial samples the former have to be corrected for a reservoir age. We present reservoir ages from dating 21 whales collected 1860-1901 and recalculating dates of 23 molluscs collected 1857-1926. Most of the whales were caught along the coast of Norway, but one is from France and one from Iceland. We assume the former mainly lived in the North and equatorial Atlantic and in the Norwegian Sea. Whales feed only on pelagic organisms and will provide the reservoir age for the open ocean surface water. However, they travel long distances and will integrate the reservoir ages of the different water masses along their way. Molluscs (dated from Norway, Spitsbergen and Arctic Canada) are stationary and monitor the sea water passing their dwelling site, but some also take up carbon from particulate food or sediment pore water. Coastal water also often contains some continental carbon. We present two different views on how to analyze and interpret the data. Mangerud recommends to use reservoir ages based on a combination of the whale and mollusc dates, i.e. 380±30 and 360±30 yr relative to Intcal04 and British oak, respectively, and a Δ R value of 20±30 for the surface water in the N-Atlantic and Norwegian Sea. Bondevik and Gulliksen maintain that the reservoir age—and Δ R—along the Norwegian coast is latitude dependant, with Δ R-values increasing from -3±22 in the South to 105±24 at Spitsbergen. Whales, reflecting North Atlantic open ocean surface water have lower Δ R (7±11) than most molluscs.

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

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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.

Influence of food on the assimilation of selected metals in tropical bivalves from the New Caledonia lagoon: Qualitative and quantitative aspects

International Nuclear Information System (INIS)

Hedouin, Laetitia; Metian, Marc; Lacoue-Labarthe, Thomas; Fichez, Renaud; Teyssie, Jean-Louis; Bustamante, Paco; Warnau, Michel

2010-01-01

The present study aimed at examining the influence of food quality and quantity on the assimilation efficiency (AE) of metals in two abundant bivalves in the New Caledonia lagoon, the oyster Isognomon isognomon and the clam Gafrarium tumidum. Bivalves were exposed via their food to the radiotracers of three metals of concern in New Caledonia ( 54 Mn, 57 Co and 65 Zn) under different feeding conditions (phytoplankton species, cell density, and cell-associated metal concentration). When bivalves were fed Heterocapsa triquetra, Emiliania huxleyi and Isochrysis galbana, AE of Mn, Co and Zn was strongly influenced by the phytoplankton species and by the metal considered. In contrast, when fed one given phytoplankton species previously exposed to different concentrations of Co, phytoplankton-associated Co load had no influence on the AE and on the retention time of the metal in both bivalves. Metals ingested with I. galbana displayed generally the highest AE in both bivalve species, except for Mn in clams for which the highest AE was observed for H. triquetra. Influence of food quantity was investigated by exposing bivalves to different cell densities of I. galbana (5 x 10 3 , 10 4 or 5 x 10 4 cell ml -1 ). As for food quality, food quantity was found to influence AE of Mn, Co and Zn, the highest AE being observed when bivalves were fed the lowest cell density. Overall, results indicate that the two bivalve species are able to adjust their feeding strategies according to the food conditions prevailing in their environment.

The control of an invasive bivalve, Corbicula fluminea, using gas impermeable benthic barriers in a large natural lake.

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Wittmann, Marion E; Chandra, Sudeep; Reuter, John E; Schladow, S Geoffrey; Allen, Brant C; Webb, Katie J

2012-06-01

Anoxia can restrict species establishment in aquatic systems and the artificial promotion of these conditions can provide an effective control strategy for invasive molluscs. Low abundances (2-20 m(-2)) of the nonnative bivalve, Asian clam (Corbicula fluminea), were first recorded in Lake Tahoe, CA-NV in 2002 and by 2010 nuisance-level population densities (>10,000 m(-2)) were observed. A non-chemical control method using gas impermeable benthic barriers to reduce dissolved oxygen (DO) concentrations available to C. fluminea was tested in this ultra-oligotrophic natural lake. In 2009, the impact of ethylene propylene diene monomer (EPDM) sheets (9 m(2), n = 6) on C. fluminea beds was tested on 1-7 day intervals over a 56 day period (August-September). At an average water temperature of 18 °C, DO concentrations under these small barriers were reduced to zero after 72 h resulting in 100 % C. fluminea mortality after 28 days. In 2010, a large EPDM barrier (1,950 m(2)) was applied to C. fluminea populations for 120 days (July-November). C. fluminea abundances were reduced over 98 % after barrier removal, and remained significantly reduced (>90 %) 1 year later. Non-target benthic macroinvertebrate abundances were also reduced, with variable taxon-specific recolonization rates. High C. fluminea abundance under anoxic conditions increased the release of ammonium and soluble reactive phosphorus from the sediment substrate; but levels of unionized ammonia were low at 0.004-0.005 mg L(-1). Prolonged exposure to anoxia using benthic barriers can provide an effective short term control strategy for C. fluminea.

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

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

2014-02-15

Short-chain chlorinated paraffins (SCCPs) are a new type of persistent organic pollutants that are of great environmental concern because of their wide distribution. In this study, surface sediments and bivalve samples were collected from the coastal area of the Bohai Sea in China. Total SCCP (ΣSCCP) concentrations in surface sediments and bivalves ranged from 97.4 ng g(-1) dry weight (dw) to 1756.7 ng g(-1) dw and 476.4-3269.5 ng g(-1) dw, respectively. C10-CPs and C11-CPs were the predominant homologue groups in all sediments and bivalves. Specific congener composition analysis and correspondence analysis indicated that the local SCCP source mainly came from CP-42 and CP-52 products, and riverine input had an important function. The biota-sediment accumulation factors of ΣSCCPs for bivalves ranged from 1.08 to 1.61, and a significant correlation indicated that the SCCP congener with higher chlorination degree was more likely to be accumulated in bivalves. Copyright © 2014. Published by Elsevier Ltd.

The reproductive cycle of the oyster Crassostrea gasar

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CHAM Gomes

Full Text Available The purpose of this study was to analyze the reproductive cycle of the oyster Crassostrea gasar (= C. brasiliana in the field and the laboratory. The reproductive cycle of the animals was evaluated in the field at Sambaqui Beach, Florianópolis, SC (27° 29′18″ S and 48° 32′12″ W from May 2008 through November 2009. In July, the animals were in the resting stage. The early growth stage began in August and was followed by the late growth stage in October. In November and December, the oysters began to enter the mature stage. Females in spawning condition were predominant during these months. The stages of the reproductive cycle were positively associated with temperature (r=0.77, P<0.01 and negatively associated with salinity (r=−0.56, P=0.042. These findings demonstrated that increased temperature and reduced salinity influence the reproductive development of Crassostrea gasar. The condition index (CI of the animals was also associated with the seawater temperature. The highest values of the condition index were observed during the months when the temperature of the seawater was gradually increasing. A laboratory experiment was performed to test the effect of salinity on the reproductive cycle of the oysters. The experiment was conducted in standardized tanks. The animals were conditioned using two salinities (24‰ and 34‰. The salinity regime influenced the development of the gonadal tissue of the oysters. A salinity of 24‰ produced greater reproductive development.

Uncharted waters: Bivalves of midway atoll and integrating mathematics into biology education

Science.gov (United States)

McCully, Kristin M.

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 the ecology and identity of large bivalves at Midway Atoll in the Northwestern Hawaiian Islands (NWHI) with research on pedagogical strategies for integrating mathematics into undergraduate biology education. The NWHI is one of the few remaining large, mainly intact, predator-dominated coral reef ecosystems and one of the world's largest marine protected areas. Previous bivalve studies focused on the black-lipped pearl oyster, Pinctada margaritifera, which was heavily harvested in the late 1920s, has not recovered, and is now a candidate species for restoration. First, I combined remote sensing, geographic information systems, SCUBA, and mathematical modeling to quantify the abundance, spatial distributions, and filtration capacity of large epifaunal bivalves at Midway Atoll. These bivalves are most abundant on the forereef outside the atoll, but densities are much lower than reported on other reefs, and Midway's bivalves are unlikely to affect plankton abundance and productivity inside the lagoon. Second, I used molecular techniques and phylogenetic reconstructions to identify pearl oysters (Pinctada) from Midway Atoll as P. maculata , a species not previously reported in Hawaii. As a small morphologically cryptic species, P. maculata may be a native species that has not been collected previously, a native species that has been identified incorrectly as the morphologically similar P. radiata, or it may be a recent introduction or natural range extension from the western Pacific. Finally, I review science education literature integrating mathematics into undergraduate biology curricula, and then present and evaluate a

PARASITIC AND SYMBIOTIC FAUNA INHABITING OYSTERS (CRASSOSTREA VIRGINICA) SAMPLED FROM THE CALOOSAHATCHEE ESTUARY, FL

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Oysters, Crassostrea virginica, inhabiting 5 sites in the Caloosahatchee River estuary were studied over a 13 month period to determine the suitability of oyster habitat in relation to their health and condition. Histological examination of 650 oysters (10 animals per station per...

Molecular analysis of bacterial microbiota associated with oysters (Crassostrea gigas and Crassostrea corteziensis) in different growth phases at two cultivation sites.

Science.gov (United States)

Trabal, Natalia; Mazón-Suástegui, José M; Vázquez-Juárez, Ricardo; Asencio-Valle, Felipe; Morales-Bojórquez, Enrique; Romero, Jaime

2012-08-01

Microbiota presumably plays an essential role in inhibiting pathogen colonization and in the maintenance of health in oysters, but limited data exist concerning their different growth phases and conditions. We analyzed the bacterial microbiota composition of two commercial oysters: Crassostrea gigas and Crassostrea corteziensis. Differences in microbiota were assayed in three growth phases: post-larvae at the hatchery, juvenile, and adult at two grow-out cultivation sites. Variations in the microbiota were assessed by PCR analysis of the 16S rRNA gene in DNA extracted from depurated oysters. Restriction fragment length polymorphism (RFLP) profiles were studied using Dice's similarity coefficient (Cs) and statistical principal component analysis (PCA). The microbiota composition was determined by sequencing temperature gradient gel electrophoresis (TGGE) bands. The RFLP analysis of post-larvae revealed homology in the microbiota of both oyster species (Cs > 88 %). Dice and PCA analyses of C. corteziensis but not C. gigas showed differences in the microbiota according to the cultivation sites. The sequencing analysis revealed low bacterial diversity (primarily β-Proteobacteria, Firmicutes, and Spirochaetes), with Burkholderia cepacia being the most abundant bacteria in both oyster species. This study provides the first description of the microbiota in C. corteziensis, which was shown to be influenced by cultivation site conditions. During early growth, we observed that B. cepacia colonized and remained strongly associated with the two oysters, probably in a symbiotic host-bacteria relationship. This association was maintained in the three growth phases and was not altered by environmental conditions or the management of the oysters at the grow-out site.

[NADPH-diaphorase activity in digestive system of gastropod molluscs Achatina fulica and Littorina littorea].

Science.gov (United States)

Zaĭtseva, O V; Kuznetsova, T V; Markosova, T G

2009-01-01

Localization and peculiarities of NO-ergic elements were studied for he first time throughout the entire length of digestive tract of the marine gastropod mollusc Achatina fulica (Prosobranchia) and the terrestrial molusc Littorina littorea (Pulmonata) by using histochemical method of detection of NADPH-diaphorase (NADPHd). NO-ergic cells and fibers were revealed in all parts of the mollusc digestive tract beginning from pharynx. An intensive NADPHd activity was found in many intraepithelial cells of the open type and in their processes in intra- and subepithelial nerve plexuses, single subepithelial neurons, granular connective tissue cells, and numerous nerve fibers among muscle elements of he digestive tract wall as well as in nerves innervating the tract. NADPHd was also present in receptor cells of he oral area and in the central A. fulica ganglia participating in innervation of the digestive tract. The digestive tract NO-ergic system ofA. fulica has a more complex organization that that of L. littorea. In the A. fulica pharynx, stomach, and midgut, directly beneath epithelium, there is revealed a complex system of glomerular structures formed by thin NADPHd-positive nerve fibers coming from the side of epithelium. More superficially under the main groups of muscle elements, small agglomerations of NADPHd-positive neurons are seen, which could be considered as primitive, non-formed microganglia. Peculiarities of distribution and a possible functional role of NO-ergic elements in the digestive tract of molluscs are discussed as compared with other invertebrate and vertebrate animals.

SHRIMP (CRANGON-CRANGON L) BROWSING UPON SIPHON TIPS INHIBITS FEEDING AND GROWTH IN THE BIVALVE MACOMA-BALTHICA (L)

NARCIS (Netherlands)

KAMERMANS, P; HUITEMA, HJ

1994-01-01

The influence of siphon browsing on the feeding behaviour and growth of Macoma balthica, a deposit-feeding bivalve, was studied in three manipulative experiments. Browsing was simulated by removing part of the inhalant siphon with scissors, or studied by exposing the bivalves to shrimps (Crangon

DIFFERENTIAL EFFECTS OF OYSTER (CRASSOSTREA VIRGINICA) DEFENSES ON CLINICAL AND ENVIRONMENTAL ISOLATES OF VIBRIO PARAHEMOLYTICUS

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Three clinical (2030, 2062, and 2107) and three environmental (1094, 1163, and ATCC 17802) isolates of Vibrio parahaemolyticus were exposed to hemocytes and plasma collected from oysters (Crassostrea virginica) to determine their susceptibility to putative oyster defenses. Clinic...

Isolation of Vibrio cholerae serotype O1 from the eastern oyster, Crassostrea virginica.

Science.gov (United States)

Hood, M A; Ness, G E; Rodrick, G E

1981-01-01

Two strains of Vibrio cholerae serotype O1 Inaba were isolated from eastern oysters, Crassostrea virginica, collected from estuarine waters in Florida during April 1980. The oyster meats and waters from which the oysters were collected had low fecal coliform counts, and the area had no prior evidence of sewage contamination. PMID:7235700

Massive settlements of the Pacific oyster, Crassostrea gigas, in Scandinavia : Original paper

DEFF Research Database (Denmark)

Wrange, Anna-Lisa; Valero, Johanna; Harkestad, Lisbeth S.

2010-01-01

The Pacific oyster (Crassostrea gigas) is an important aquaculture species world-wide. Due to its wide environmental tolerance and high growth rate, it has also become a successful invader in many areas, leading to major ecosystem changes. Low water temperatures were previously believed to restri...... settlement in 2006, and in Norway, populations are established along the southwest coast to 60°N....

Massive settlements of the Pacific oyster, Crassostrea gigas, in Scandinavia : Invasion note

DEFF Research Database (Denmark)

Wrange, Anna-Lisa; Valero, Johanna; Harkestad, Lisbeth S.

2010-01-01

The Pacific oyster (Crassostrea gigas) is an important aquaculture species world-wide. Due to its wide environmental tolerance and high growth rate, it has also become a successful invader in many areas, leading to major ecosystem changes. Low water temperatures were previously believed to restri...... settlement in 2006, and in Norway, populations are established along the southwest coast to 60A degrees N....

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

Moderate establishment success of Pacific oyster, Crassostrea gigas, on a sheltered intertidal mussel bed

DEFF Research Database (Denmark)

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

2015-01-01

The Pacific oyster (Crassostrea gigas Thunberg 1793) is introduced into marine ecosystems worldwide. In Denmark, C. gigas was introduced into the micro tidal Limfjord, around 1972 for aquaculture. This study describes the population structure of C. gigas at Agger Tange in 2007, 2009, 2010 and 2011...

Seasonal variability in somatic and reproductive investment of the bivalve

NARCIS (Netherlands)

Santos, S.; Cardoso, J.F.M.F.; Carvalho, C.; Luttikhuizen, P.C.; van der Veer, H.W.

2011-01-01

Monthly investment in soma and gonads in the bivalve Scrobicularia plana is described for three populations along its distributional range: Minho estuary, Portugal; Westerschelde estuary, The Netherlands and Buvika estuary, Norway. Seasonal cycles in body mass (BMI), somatic mass (SMI) and

Conservation thinning in secondary forest: negative but mild effect on land molluscs in closed-canopy mixed oak forest in Sweden.

Directory of Open Access Journals (Sweden)

Birte Rancka

Full Text Available Secondary succession is changing the character of many temperate forests and often leads to closed-canopy stands. In such forests set aside for conservation, habitat management alternatives need to be tested experimentally, but this is rarely done. The Swedish Oak Project compares two often debated alternatives: minimal intervention and non-traditional active management (conservation thinning on plots of each type replicated at 25 sites. We study responses of several taxa, and here report results for land molluscs. They are considered to be sensitive to more open, drier forest and we predicted a negative effect of the thinning (26% reduction of the basal area; mean value for 25 experimental forests. We sampled molluscs in the litter in ten 20 x 25 cm subplots, and by standardised visual search, in each plot. In total, we recorded 53 species of snails and slugs (24 369 individuals and the mean species richness in plots was 17. Two seasons after thinning, mean (± SE species richness had decreased by 1.4 (± 0.9 species in thinning plots, but increased by 0.7 (± 1.0 species in minimal intervention plots, a significant but small change with considerable variation among sites. In matched comparisons with minimal intervention, thinning reduced the overall abundance of molluscs. Most species responded negatively to thinning - but only five of the 53 species were significantly affected, and reproduction seemed to be negatively affected in only one species. An ordination analysis did not reveal any particular change in the species community due to thinning. Thus, the negative effect of conservation thinning on land molluscs was apparently mild - one reason was that many trees, shrubs and other forest structures remained after the treatment. Conservation thinning may be recommended, since other taxa are favoured, but minimal intervention is also a useful form of management for molluscs and saproxylic taxa.

Organisms associated with the sandy-beach bivalve Donax serra ...

African Journals Online (AJOL)

57: 134-136. BROWN, AC. & WEBB, S.c. 1994. Organisms associated \\.,.,ith burrowing whelks of the genus Bullia. S Afr. 1. Zool. 29: 144-151. BROWN, A.C., STENTON-DOZEY, J.~.E. & TRUEMAN, E.R.. 1989. Sandy-beach bivalves and gastropods; a comparison between Donax serra and Ruilia digitalis. Adv. mar. Bioi. 25:.

First record of molluscs naturally infected with Angiostrongylus cantonensis (Chen, 1935 (Nematoda: Metastrongylidae in Brazil

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Roberta Lima Caldeira

2007-11-01

Full Text Available Seeking the identification of Angiostrongylus cantonensis as a potential etiological agent of three clinical cases of eosinophilic meningitis, mollusc specimens were collected in the state of Espírito Santo, Brazil. The snails were identified as Sarasinula marginata (45 specimens, Subulina octona (157, Achatina fulica (45 and Bradybaena similaris (23. Larvae obtained were submitted to polymerase chain reaction and restriction fragment length polymorphism diagnosis. Their genetic profile were corresponded to A. cantonensis. Rattus norvegicus experimentally infected with third-stage larvae, developed menigoencephalitis, and parasites became sexually mature in the lungs. Additionally, larvae obtained from A. fulica snails, from São Vicente, state of São Paulo, also showed genetic profiles of this nematode. This is the first record of Brazilian molluscs infected with this nematode species.

Evaluation of the concentration of heavy metals in sea water, silt and rock oysters, Crassostrea iridescens, from Manzanillo bay

International Nuclear Information System (INIS)

Guerrero Carbajal, Y.C.

1993-01-01

Some essential metals such as Fe, Ni, Cu and Zn were evaluated by X-ray spectroscopy in water, soil and rock oyster Crassostrea iridescens from Manzanillo Bay. Four samplings were taken every two months during 1991. Concentration range on liofilized oysters for Fe was determined between 76 and 172 μ g/g dry weight, Ni 9-21 μ g/g dry weight, Cu 21-123 μ g/g dry weight and Zn 216-885 μ g/g dry weight. Ni concentration was above the toxicological tolerance level for crustaceans (5 μ g/g); Cu was above maxima permission limited (MPL) from FAO for molluscs (70 μ g/g); Zn was below MPL for oysters (1000 μ g/g). For Fe there is no MPL for oyster or any other aquatic organisms. Concentration and accumulation factors for the elements measured suggested the filtration oyster activity. Fe concentration range in water was 27-2266 μ g/l. This value is above the ecological aquatic life criteria in Mexico (50 μ g/l). For Cu the concentration range was 4-536 μ g/l., which is above the MPL for Mexican Legislation (5 μ g/l). Chemical elements detected in soil were the essential metal mentioned before. However, the heavy metals concentrations for soil, from Manzanillo Bay, were higher than those reported in other polluted regions in both Mexican coasts. Concentration range for Fe was 30661-76332 μ g/g, Ni 19-180 μ g/g, Cu 56-270 μ g/g and Zn 33-1377 μ g/g. Contamination problem in Manzanillo Bay must be considered as an evidence of potential risk, since the essential metals are reaching levels that could endanger aquatic life. (Author). 87 refs, 20 figs, 6 tabs

Neuropeptides encoded by the genomes of the Akoya pearl oyster Pinctata fucata and Pacific oyster Crassostrea gigas: a bioinformatic and peptidomic survey.

Science.gov (United States)

Stewart, Michael J; Favrel, Pascal; Rotgans, Bronwyn A; Wang, Tianfang; Zhao, Min; Sohail, Manzar; O'Connor, Wayne A; Elizur, Abigail; Henry, Joel; Cummins, Scott F

2014-10-02

Oysters impart significant socio-ecological benefits from primary production of food supply, to estuarine ecosystems via reduction of water column nutrients, plankton and seston biomass. Little though is known at the molecular level of what genes are responsible for how oysters reproduce, filter nutrients, survive stressful physiological events and form reef communities. Neuropeptides represent a diverse class of chemical messengers, instrumental in orchestrating these complex physiological events in other species. By a combination of in silico data mining and peptide analysis of ganglia, 74 putative neuropeptide genes were identified from genome and transcriptome databases of the Akoya pearl oyster, Pinctata fucata and the Pacific oyster, Crassostrea gigas, encoding precursors for over 300 predicted bioactive peptide products, including three newly identified neuropeptide precursors PFGx8amide, RxIamide and Wx3Yamide. Our findings also include a gene for the gonadotropin-releasing hormone (GnRH) and two egg-laying hormones (ELH) which were identified from both oysters. Multiple sequence alignments and phylogenetic analysis supports similar global organization of these mature peptides. Computer-based peptide modeling of the molecular tertiary structures of ELH highlights the structural homologies within ELH family, which may facilitate ELH activity leading to the release of gametes. Our analysis demonstrates that oysters possess conserved molluscan neuropeptide domains and overall precursor organization whilst highlighting many previously unrecognized bivalve idiosyncrasies. This genomic analysis provides a solid foundation from which further studies aimed at the functional characterization of these molluscan neuropeptides can be conducted to further stimulate advances in understanding the ecology and cultivation of oysters.

Otimização do processo de depuração de moluscos bivalves

OpenAIRE

Correia, Maria Helena Oliveira Casimiro

2016-01-01

A contaminação microbiológica de moluscos bivalves constitui uma das principais preocupações inerentes à segurança alimentar desta importante fonte de receitas para a economia portuguesa. Os bivalves capturados ou produzidos em zonas estuarinas ou lagunares devem passar por um processo de depuração, para redução dos níveis de contaminação microbiológica, antes da sua comercialização. Este trabalho teve como principal objetivo o desenvolvimento de sistemas modulares de dep...

Biokinetic behavior of Tc in the red abalone, Haliotis rufescens: a reassessment

International Nuclear Information System (INIS)

Beasley, T.M.; Lorz, H.V.; Gonor, J.J.

1981-01-01

The biokinetic behavior of /sup 95m/Tc in the red abalone, Haliotis rufescens, is reviewed in light of recent experiments on other molluscs. Additional experimentation has confirmed that, when uptake is directly from labeled seawater, abalone exhibit concentration factors in excess of 100. Bivalve molluscs under the same experimental conditions have concentration factors that do not exceed 2. However, uptake and loss kinetics cannot be described by a single compartment model as had been previously advanced. Assimilation of /sup 95m/Tc by the abalone following a single feeding of labeled macroalga, Nereocystis pyrifera, is high (approx. 45%) and loss kinetics are similar to those observed following direct uptake from seawater

Biokinetic behavior of technetium in the red abalone, Haliotis rufescens: a re-assessment

Energy Technology Data Exchange (ETDEWEB)

Beasley, T.M.; Lorz, H.V.; Gonor, J.J. (Oregon State Univ., Newport (USA). Marine Science Center)

1982-10-01

The biokinetic behavior of sup(95m)Tc in the red abalone, haliotis rufescens, is reviewed in light of recent experiments with other molluscs. Additional experimentation has confirmed that, when uptake is directly from labeled seawater, abalones exhibit concentration factors in excess of 100. Bivalve molluscs under the same experimental conditions have concentration factors that do not exceed 2. However, uptake and loss kinetics in the abalone cannot be described by a single compartment model as had been previously advanced. Assimilation of sup(95m)Tc by abalones following a single feeding of labeled macroalga, Nereocystis luetkeana, approximately equal to 45% and loss kinetics are similar to those observed following direct uptake from seawater.

Biokinetic behavior of technetium in the red abalone, Haliotis rufescens: a re-assessment

Energy Technology Data Exchange (ETDEWEB)

Beasley, T.M.; Lorz, H.V.; Gonor, J.J.

1982-10-01

The biokinetic behavior of /sup 95m/Tc in the red abalone, Haliotis rufescens, is reviewed in light of recent experiments with other molluscs. Additional experimentation has confirmed that, when uptake is directly from labelled seawater, abalones exhibit concentration factors in excess of 100. Bivalve molluscs under the same experimental conditions have concentration factors that do not exceed 2. However, uptake and loss kinetics in the abalone cannot be described by a single compartment model as had been previously advanced. Assimilation of /sup 95m/Tc by abalones following a single feeding of labeled macroalga, Nereocystis luetkeana, is approximately 45% and loss kinetics are similar to those observed following direct uptake from seawater.

Biokinetic behavior of technetium in the red abalone, Haliotis rufescens: a re-assessment

International Nuclear Information System (INIS)

Beasley, T.M.; Lorz, H.V.; Gonor, J.J.

1982-01-01

The biokinetic behavior of sup(95m)Tc in the red abalone, haliotis rufescens, is reviewed in light of recent experiments with other molluscs. Additional experimentation has confirmed that, when uptake is directly from labeled seawater, abalones exhibit concentration factors in excess of 100. Bivalve molluscs under the same experimental conditions have concentration factors that do not exceed 2. However, uptake and loss kinetics in the abalone cannot be described by a single compartment model as had been previously advanced. Assimilation of sup(95m)Tc by abalones following a single feeding of labeled macroalga, Nereocystis luetkeana, approximately equal to 45% and loss kinetics are similar to those observed following direct uptake from seawater. (author)

Phenology of abundance of bivalve spat and of their epibenthic predators: limited evidence for mismatches after cold winters

NARCIS (Netherlands)

Dekker, R.; Beukema, J.J.

2014-01-01

Annual recruitment of bivalves in the Wadden Sea is usually more successful in summers after cold than after mild winters. The new generation (0-group) of the main predators (shrimps and shore crabs) of early benthic stages of bivalves appear later in spring on tidal flats after colder winters. If

Coral and mollusc resistance to ocean acidification adversely affected by warming

Science.gov (United States)

Rodolfo-Metalpa, R.; Houlbrèque, F.; Tambutté, É.; Boisson, F.; Baggini, C.; Patti, F. P.; Jeffree, R.; Fine, M.; Foggo, A.; Gattuso, J.-P.; Hall-Spencer, J. M.

2011-09-01

Increasing atmospheric carbon dioxide (CO2) concentrations are expectedto decrease surface ocean pH by 0.3-0.5 units by 2100 (refs , ), lowering the carbonate ion concentration of surfacewaters. This rapid acidification is predicted to dramatically decrease calcification in many marine organisms. Reduced skeletal growth under increased CO2 levels has already been shown for corals, molluscs and many other marine organisms. The impact of acidification on the ability of individual species to calcify has remained elusive, however, as measuring net calcification fails to disentangle the relative contributions of gross calcification and dissolution rates on growth. Here, we show that corals and molluscs transplanted along gradients of carbonate saturation state at Mediterranean CO2 vents are able to calcify and grow at even faster than normal rates when exposed to the high CO2 levels projected for the next 300 years. Calcifiers remain at risk, however, owing to the dissolution of exposed shells and skeletons that occurs as pH levels fall. Our results show that tissues and external organic layers play a major role in protecting shells and skeletons from corrosive sea water, limiting dissolution and allowing organisms to calcify. Our combined field and laboratory results demonstrate that the adverse effects of global warming are exacerbated when high temperatures coincide with acidification.

FEATURES OF THE GEOGRAPHICAL DISTRIBUTION OF TERRESTRIAL MOLLUSCS IN THE CAUCASUS

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M. Z. Magomedova

2015-01-01

Full Text Available Aim. High population, high proliferation rates, a large species diversity, low mobility and small ability to overcome geographic barriers, ease of collecting material and sensitive response to changes in the external environment makes this group a convenient object of biogeographic and ecological research. Methods. The inventory of Caucasian ground malacofauna made it possible to make a complete list of species; their characteristics were determined by the geographical distribution of major natural regions of the Caucasus. Results. The comparative analysis of the geographical distribution of terrestrial molluscs on key areas of the Caucasus showed that among the 352 species belonging to 140 genera of 36 families, most richly represented Western Caucasus, which accounts for 51% or 181 species from 80 genera of 20 families, while the share of Armenian, Eastern and Central Caucasus accounts for 35-37%. Talysh, in turn, is characterized by the presence of only 11% of the species composition of the Caucasian land mollusc. Caucasus limited in distribution among the analyzed species is 72% or 255 species belonging to 104 genera of 24 families. Conclusion. The results prove the species diversity of the different regions of theCaucasus and could serve as the basis to reconsider the possible ways of formation of fauna of the region discussed. 

Angiostrongylus cantonensis (Nematode: Metastrongyloidea in molluscs from harbour areas in Brazil

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Omar dos Santos Carvalho

2012-09-01

Full Text Available Angiostrongylus cantonensis is the most common aetiological agent of human eosinophilic meningoencephalitis. Following a report indicating the presence of this parasite in Brazil in 2007, the present study was undertaken to investigate the presence of A. cantonensis in the surrounding Brazilian port areas. In total, 30 ports were investigated and the following molluscs were identified: Achatina fulica, Belocaulus sp., Bradybaena similaris sp., Cyclodontina sp., Helix sp., Leptinaria sp., Melampus sp., Melanoides tuberculata, Phyllocaulis sp., Pomacea sp., Pseudoxychona sp., Rhinus sp., Sarasinula marginata, Streptaxis sp., Subulina octona, Succinea sp., Tomigerus sp., Wayampia sp. and specimens belonging to Limacidae and Orthalicinae. Digestion and sedimentation processes were performed and the sediments were examined. DNA was extracted from the obtained larvae and the internal transcribed spacer region 2 was analysed by polymerase chain reaction-restriction fragment length polymorphism after digestion with the endonuclease ClaI. Of the 30 ports investigated in this study, 11 contained molluscs infected with A. cantonensis larvae. The set of infected species consisted of S. octona, S. marginata, A. fulica and B. similaris. A total of 36.6% of the investigated ports were positive for A. cantonensis, indicating a wide distribution of this worm. It remains uncertain when and how A. cantonensis was introduced into South America.

PARASITIC AND SYMBIONIC FAUNA IN OYSTERS (CRASSOSTREA VIRGINICA) COLLECTED FROM THE CALOOSAHATCHEE RIVER AND ESTUARY, FLORIDA

Science.gov (United States)

Studies of oysters, Crassostrea virginica, collected from ten sites in the Caloosahatchee River and Estuary, Florida, revealed a varied parasite and symbiotic fauna that have never been reported from this area. Organisms observed included ovacystis virus infecting gametes...

Coral and mollusc resistance to ocean acidification adversely affected by warming

OpenAIRE

Rodolfo-Metalpa, R; Houlbrèque, F; Tambutté, E; Boisson, F; Baggini, C; Patti, FP; Jeffree, R; Fine, M; Foggo, A; Gattuso, JP; Hall-Spencer, JM

2011-01-01

Increasing atmospheric carbon dioxide (CO 2) concentrations are expectedto decrease surface ocean pH by 0.3-0.5 units by 2100 (refs,), lowering the carbonate ion concentration of surfacewaters. This rapid acidification is predicted to dramatically decrease calcification in many marine organisms. Reduced skeletal growth under increased CO 2 levels has already been shown for corals, molluscs and many other marine organisms. The impact of acidification on the ability of individual species to cal...

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...

Deciphering the link between doubly uniparental inheritance of mtDNA and sex determination in bivalves: Clues from comparative transcriptomics

Science.gov (United States)

Capt, Charlotte; Renaut, Sébastien; Ghiselli, Fabrizio; Milani, Liliana; Johnson, Nathan A.; Sietman, Bernard E.; Stewart, Donald; Breton, Sophie

2018-01-01

Bivalves exhibit an astonishing diversity of sexual systems and sex-determining mechanisms. They can be gonochoric, hermaphroditic or androgenetic, with both genetic and environmental factors known to determine or influence sex. One unique sex-determining system involving the mitochondrial genome has also been hypothesized to exist in bivalves with doubly uniparental inheritance (DUI) of mtDNA. However, the link between DUI and sex determination remains obscure. In this study, we performed a comparative gonad transcriptomics analysis for two DUI-possessing freshwater mussel species to better understand the mechanisms underlying sex determination and DUI in these bivalves. We used a BLAST reciprocal analysis to identify orthologs between Venustaconcha ellipsiformis and Utterbackia peninsularis and compared our results with previously published sex-specific bivalve transcriptomes to identify conserved sex-determining genes. We also compared our data with other DUI species to identify candidate genes possibly involved in the regulation of DUI. A total of ∼12,000 orthologous relationships were found, with 2,583 genes differentially expressed in both species. Among these genes, key sex-determining factors previously reported in vertebrates and in bivalves (e.g., Sry, Dmrt1, Foxl2) were identified, suggesting that some steps of the sex-determination pathway may be deeply conserved in metazoans. Our results also support the hypothesis that a modified ubiquitination mechanism could be responsible for the retention of the paternal mtDNA in male bivalves, and revealed that DNA methylation could also be involved in the regulation of DUI. Globally, our results suggest that sets of genes associated with sex determination and DUI are similar in distantly-related DUI species.

Thyasirid bivalves from Cretaceous and Paleogene cold seeps

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Krzysztof Hryniewicz

2017-11-01

Full Text Available We present a systematic study of thyasirid bivalves from Cretaceous to Oligocene seep carbonates worldwide. Eleven species of thyasirid bivalves are identified belonging to three genera: Conchocele, Maorithyas, and Thyasira. Two species are new: Maorithyas humptulipsensis sp. nov. from middle Eocene seep carbonates in the Humptulips Formation, Washington State, USA, and Conchocele kiritachiensis sp. nov. from the late Eocene seep deposit at Kiritachi, Hokkaido, Japan. Two new combinations are provided: Conchocele townsendi (White, 1890 from Maastrichtian strata of the James Ross Basin, Antarctica, and Maorithyas folgeri (Wagner and Schilling, 1923 from Oligocene rocks from California, USA. Three species are left in open nomenclature. We show that thyasirids have Mesozoic origins and appear at seeps before appearing in “normal” marine environments. These data are interpreted as a record of seep origination of thyasirids, and their subsequent dispersal to non-seep environments. We discuss the age of origination of thyasirids in the context of the origin of the modern deep sea fauna and conclude that thyasirids could have deep sea origins. This hypothesis is supported by the observed lack of influence of the Cretaceous and Paleogene Oceanic Anoxic Events on the main evolutionary lineages of the thyasirids, as seen in several other members of the deep sea fauna.

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

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,

A geographical information system for the management of the aquaculture data in the Adriatic Sea – the Strengthening of Centres for Aquaculture Production and Safety surveillance in the Adriatic countries experience: Present capabilities, tools and functions

Directory of Open Access Journals (Sweden)

Susanna Tora

2017-11-01

Full Text Available The European Commission (EC regulation no. 854/2004 requires a systematic monitoring of chemical and microbiological contaminants in live bivalve molluscs, live echinoderms, live tunicates and live marine gastropods for human consumption through surveillance plans to be implemented in all European Union (EU countries.A consortium of five Adriatic countries was set up in the framework of the Instrument of Pre-accession Assistance Adriatic Cross-border Cooperation Programme (IPA Adriatic CBC 2007- 2013 with the aim of collecting data and distribute information on harvesting and production in mollusc areas. A web-based geographical information system (GIS application was developed to support the partners to manage data and to make these data available to final users, policy makers and to risk assessors. The GIS for the Strengthening of Centres for Aquaculture Production and Safety surveillance in the Adriatic countries (CAPS2 is divided into two levels, the national and the supranational one, and it distributes spatial and epidemiological information coming from various data acquisition and management sites. The great innovation is the possibility for each country to use online drawing, modifying and change of the geographic areas according to national surveillance needs. Currently it hosts data coming from about 230 production and relay areas with more than 29,478 laboratory tests performed on collected samples since August 2014. Data collected are used by each national competent authority to classify production or relay areas according to the EC regulation mentioned and to conduct risk assessment studies to evaluate the level of consumers’ exposure to contaminants in the consumption of bivalve mollusc products.

The influence of different microalgal diets on Crassostrea angulata (Lamarck, 1819 broodstock conditioning

Directory of Open Access Journals (Sweden)

Catarina Anjos

2014-06-01

Full Text Available The Portuguese oyster Crassostrea angulata shows great potential in oyster farming. In Europe, pure populations of this species were observed only in the southern coasts of Portugal and Spain, namely in Rio Sado, Rio Mira and Guadalquivir. The conservation of C. angulata populations is important in the context of production diversification and biodiversity preservation. In this way the zootechnological development for seed hatchery production is extremely important. Broodstock conditioning is a key step in the process of rearing bivalve in hatchery. Many factors regulate the reproductive cycle, being food the most important. However the influence of the nutritional quality of different phytoplankton on sexual maturation has been poorly explored. To evaluate the effects of different diets on C. angulata sexual maturity, broodstock were conditioned with different food regimes: Diet 1: bi-specific combination of Pavlova lutheri and Isochrysis galbana clone T-ISO (1:1; Diet 2: tri-specific combination of P. lutheri, I galbana clone T-ISO and Skeletonema constatum (1:1:1; Diet 3: bi-specific combination of S. constatum and Chaetoceros calcitrans (1:1 and Diet 4: tri-specific combination of P. lutheri, S. constatum and C. calcitrans (1:1:1. During conditioning, condition index and gonad histological analysis were performed. Results showed heterogeneity between diets. At the beginning of conditioning 60% of individuals were in resting (stage 0, 30% were males in early gametogenesis (stage I and 10% were females in mature stage (stage III. At the end of the conditioning, the most effective diet was the Diet 3 (60 % of mature oysters with a mean condition index value of 2.83±0.95. Whereas those fed with Diet 1 have an unsuccessfully gonadic development, with 80% of individuals in resting stage. Indeed, the condition index, in Diet 1 decreased during the conditioning period. The results obtained in this study reinforce the idea that the diatom microalgae

The invasive Pacific oyster, Crassostrea gigas, in Scandinavia coastal waters

DEFF Research Database (Denmark)

Dolmer, Per; Holm, Mark Wejlemann; Strand, Åsa

visualized the need for a continued collaboration between scientists in the Scandinavian countries, as the bio-invasion is a cross-border issue and management actions then have to be synchronized, and based on a “state of the art” knowledge of the Scandinavian bio-invasion of the species. The risk assessment......A massive invasion of the Pacific oyster, Crassostrea gigas , has occurred in Scandinavia during the last decade. The introduction and dispersal was described through collaboration between scientists from Sweden, Denmark and Norway. This work has been followed up by national activities that clearly...

Sensitivity of oysters (Crassostrea Brasiliana) to radiation

International Nuclear Information System (INIS)

Mattiolo Marchese, S.R.; Mastro, N.L. del

1997-01-01

Various foods including oysters, crabs and shrimps have been shown to be possible transmitters of Vibrio ssp. Irradiation of sea-foods is being considered an alternative to intervention measures in Public Health against food borne diseases. The aim of this work was to establish, the radiation resistance of the oysters Crassostrea brasiliana. The oysters were irradiated with Co-60 radiation with doses of 0, 1.5, 3 and 6 kGy. Survival curves as a function of time showed that 100% of the oysters irradiated with doses of 3 kGy survived at least 6 days. 100% those irradiated with 6 kGy survived 3 days. The obtained results are auspicious considering that a dose of 2 kGy is already effective in the diminishing of the microbial load on oysters. (author)

Growth rates and geochemical proxies in Late Campanian bivalves - New insights from micro-X-ray Fluorescence mapping and numerical growth modelling

Science.gov (United States)

de Winter, Niels; Goderis, Steven; van Malderen, Stijn; Vanhaecke, Frank; Claeys, Philippe

2017-04-01

Understanding the Late Cretaceous greenhouse climate is of vital importance for understanding present and future climate change. While a lot of good work has been done to reconstruct climate in this interesting period, most paleoclimatic studies have focused on long-term climate change[1]. Alternatively, multi-proxy records from marine bivalves provide us with a unique opportunity to study past climate on a seasonal scale. However, previous fossil bivalve studies have reported ambiguous results with regard to the interpretation of trace element and stable isotope proxies in marine bivalve shells[2]. One major problem in the interpretation of such records is the bivalve's vital effect and the occurrence of disequilibrium fractionation during bivalve growth. Both these problems are linked to the annual growth cycle of marine bivalves, which introduces internal effects on the incorporation of isotopes and trace elements into the shell[3]. Understanding this growth cycle in extinct bivalves is therefore of great importance for the interpretation of seasonal proxy records in their shells. In this study, three different species of extinct Late Campanian bivalves (two rudist species and one oyster species) that were found in the same stratigraphic interval are studied. Micro-X-Ray Fluorescence line scanning and mapping of trace elements such as Mg, Sr, S and Zn, calibrated by LA-ICP-MS measurements, is combined with microdrilled stable carbon and oxygen isotope analysis on the well-preserved part of the shells. Data of this multi-proxy study is compared with results from a numerical growth model written in the open-source statistics package R[4] and based on annual growth increments observed in the shells and shell thickness. This growth model is used together with proxy data to reconstruct rates of trace element incorporation into the shell and to calculate the mass balance of stable oxygen and carbon isotopes. In order to achieve this goal, 2D mapping of bivalve shell

The potential accumulation of polycyclic aromatic hydrocarbons in phytoplankton and bivalves in Can Gio coastal wetland, Vietnam.

Science.gov (United States)

Thuy, Hoang Thi Thanh; Loan, Tu Thi Cam; Phuong, Trinh Hong

2018-05-12

Polycyclic aromatic hydrocarbons (PAHs) are one of the most important classes of anthropogenic persistent organic contaminants in the marine environment. This review discusses a whole range of findings that address various aspects of the bioaccumulation of PAHs in two common marine biota (phytoplankton and bivalves) globally and especially for Can Gio coastal wetland, Vietnam. The published information and collected data on the bioconcentration and accumulation mechanisms of PAHs as well as implications for Can Gio coastal wetland are compiled for phytoplankton and bivalves. PAHs are still released to Can Gio coastal environments from various sources and then transported to coastal environments through various physical processes; they may enter marine food chains and be highly accumulated in phytoplankton and bivalves. Thus, PAHs' bioaccumulation should be considered as one important criterion to assess the water's quality, directly linked to human health due to seafood consumption. Ecologically, Can Gio coastal wetland plays an important role to the South Vietnam key economic zone. However, it is also an area of potential PAHs inputs. With the abundant phytoplankton and bivalves in Can Gio coastal wetland, the PAHs bioaccumulation in these biota is inevitably detected. Thus, further study on the bioavailability of these contaminants is urgently needed in order to mitigate their negative effects and protect the ecosystems.

Molecular evidence of the protozoan parasite Marteilia refringens in Crassostrea gigas and Crassostrea corteziensis from the Gulf of California

Directory of Open Access Journals (Sweden)

José Manuel Grijalva-Chon

2015-09-01

Full Text Available The search for exotic pathogens related to the outbreaks and in surveillance samplings of the Mexican oyster farms, is a recent activity achieved by academic institutions and state committees for Aquatic Animal Health, with remarkable results. In samples of Crassostrea gigas collected through December 2009, January 2010 and November 2010, and of C. corteziensis in September 2011, the protozoan Marteilia refringens was detected for the first time in the Gulf of California. The carrier oysters were from cultures without abnormal mortality rates, whereby, the use of histology, in situ hybridization and transmission electron microscopy studies are necessary to determine if M. refringens has become established in the Gulf of California oyster cultures. Detection of M. refringens is of great concern to the global oyster farming industry.

Application of photostimulated luminescence (PSL) to detect irradiated molluscs

International Nuclear Information System (INIS)

Marchesani, G.; Chiaravalle, A.E.; Chiesa, L.M.

2011-01-01

Complete text of publication follows. In contrast to thermally processed foods, irradiation is a cold treatment both to reduce microbiological contamination and to increase the shelf-life of raw seafood. According to the list of States' authorizations molluscs can be irradiated in a range of 0.5 / 3 kGy only in authorized countries (e.g. UK, Belgium and Czech Republic). Therefore the aim of this study is to identify, at different dose levels (0.5, 1, 1.5, 2, 3 kGy), irradiated oysters, clams and mussels using luminescence materials from different sites (shells and pulps) and to determine sample sensitivity for previous screening result confirmation. A total number of 10 samples for each species were analyzed by both procedures: screening and calibrated PSL. Samples were irradiated using a low energy X-ray irradiator (RS-2400, Radsource Inc.) with the following operational settings: 150 kV and 45 mA. Whole pulps were simply dispensed into a clean Petri-dish whereas shells powder required to be fixed as a thick layer with silicone grease. Results obtained showed that screening analysis can be used to identify correctly all irradiated and non irradiated samples. Particularly untreated sample exhibited a sensitivity index from 2 to 4 order of magnitude greater than the exposed sample one, while for exposed specimen calibrated PSL signals, after re-irradiation at defined dose, were of the same order of the first measurement (initial PSL counts). In conclusion mineral debris contaminating pulps and biocarbonates from shells can be considered reliable radioinduced markers and PSL techniques can be easily applied for rapid and simple analysis to identify irradiated molluscs in official controls.

Wood-Boring Bivalves (Mollusca: Teredinidae, Pholadidae) of Pacific coast of Colombia

International Nuclear Information System (INIS)

Cantera K, Jaime R

2010-01-01

Twelve species of wood-boring bivalves, ten of the family Teredinidae and two of family Pholadidae were collected in mangroves at 6 locations of the Pacific coast of Colombia. This paper presents a brief escription of these species, including size, ecological notes and geographical distribution.

Parasitological survey of mangrove oyster, Crassostrea rhizophorae, in the Pacoti River Estuary, Ceará State, Brazil.

Science.gov (United States)

Sabry, Rachel Costa; Gesteira, Tereza Cristina Vasconcelos; Magalhães, Aimê Rachel Magenta; Barracco, Margherita Anna; Guertler, Cristhiane; Ferreira, Liana Pinho; Vianna, Rogério Tubino; da Silva, Patrícia Mirella

2013-01-01

The mangrove oyster, Crassostrea rhizophorae (Bivalvia, Ostreidae) is commonly collected by fisherwomen in the estuaries of the Ceará State (CE), Northeastern Brazil. Despite the socioeconomic importance of this natural resource, there are few studies on the health of the oysters in this region. This study aimed to survey pathological changes in the mangrove oyster C. rhizophorae in the estuary of the Pacoti River, CE. Adult oysters were collected in August 2008 (N=450) and December 2009 (N=450) at three sites of the Pacoti estuary and in 2010 (N=600) samplings were done quarterly at one site which has showed the higher prevalence de Perkinsus. Macroscopical and histological analyses were used to evaluate pathological changes, Ray's Fluid Thioglycollate Medium (RFTM) to detect Perkinsus spp. and polymerase chain reactions (PCR) and DNA sequencing to identify Perkinsus species. In 2009, RFTM assay detected Perkinsus sp. infecting the tissues of C. rhizophorae with low prevalences of 1.3%, 6.7% e 7.3% in sites 1, 2 and 3, respectively, and in 2010, in site 3, prevalence was 2% (12 of 600 oysters). PCR did not confirm any positive case in 2009 and only 5 in 2010. The phylogenetic analyses strongly indicate that the Perkinsus species infecting oysters C. rhizophorae of this study belongs to Perkinsus beihaiensis. The histology confirmed 11 cases of Perkinsus sp. infecting the C. rhizophorae in 2009, and only two cases in 2010. Nematopsis sp. was the protozoan observed with greater prevalence (up 96.7%). Other found protozoa were: Trichodina, Sphenophrya, Ancistrocoma - like and an unknown ovarian parasite. The metazoa found were the polychaete Polydora with high prevalences, a turbellarian, possibly of the genus Urastoma, an unidentified digenean metacercariae and larvae of cestode Tylocephalum. A continuous monitoring of diseases in bivalves from this natural population is recommended, since the phylogenetic analyses indicate the occurrence of P. beihaiensis

Molluscs associated with the macroalgae of the genus Gracilaria (Rhodophyta): importance of algal fronds as microhabitat in a hypersaline mangrove in Northeastern Brazil.

Science.gov (United States)

Queiroz, R N M; Dias, T L P

2014-08-01

The fronds of marine macroalgae play an important role in coastal ecosystems because the algae banks are utilized as a microhabitat by different taxa, including molluscs, one of the most abundant and diverse animals of marine ecosystems. In this study, we characterized the malacofauna associated with the macroalgae Gracilaria domingensis (Kützing) Sonder ex Dickie 1874 and Gracilaria cuneata Areschoug 1854 of a hypersaline mangrove on the northern coast of the state of Rio Grande do Norte, Northeastern Brazil. The first alga dominates in the rainy season and it is substituted by second one in the dry period. A total of 1,490 molluscs were surveyed, representing 56 species in 29 families: 1,081 were associated with G. domingensis and 409 with G. cuneata, the latter showing the greater diversity (H'=1.25). Columbellidae, Neritidae, Pyramidellidae and Cerithiidae were among the most representative families in the number of species and individuals. The micromolluscs were dominant in the algal microhabitat, constituting 74.63% of the malacofauna recorded. The columbellid Parvanachis obesa (C. B. Adams, 1845) was the dominant species followed by the neritid Neritina virginea (Linnaeus, 1758) in both algae. In spite of the annual alternated succession of the algae species, at least 15 mollusc species are common for these algae. Furthermore, juveniles of P. obesa were recorded in both seasons, indicating a continuous reproduction. Possible reasons for difference in abundance, diversity and dominance of molluscs living on these algae are discussed. Both species of substrate-algae represent an important microhabitat for refuge, feeding and the reproduction of small-sized mollusc species during rainy and dry seasons.

Molluscs associated with the macroalgae of the genus Gracilaria (Rhodophyta: importance of algal fronds as microhabitat in a hypersaline mangrove in Northeastern Brazil

Directory of Open Access Journals (Sweden)

RNM Queiroz

Full Text Available The fronds of marine macroalgae play an important role in coastal ecosystems because the algae banks are utilized as a microhabitat by different taxa, including molluscs, one of the most abundant and diverse animals of marine ecosystems. In this study, we characterized the malacofauna associated with the macroalgae Gracilaria domingensis (Kützing Sonder ex Dickie 1874 and Gracilaria cuneata Areschoug 1854 of a hypersaline mangrove on the northern coast of the state of Rio Grande do Norte, Northeastern Brazil. The first alga dominates in the rainy season and it is substituted by second one in the dry period. A total of 1,490 molluscs were surveyed, representing 56 species in 29 families: 1,081 were associated with G. domingensis and 409 with G. cuneata, the latter showing the greater diversity (H′=1.25. Columbellidae, Neritidae, Pyramidellidae and Cerithiidae were among the most representative families in the number of species and individuals. The micromolluscs were dominant in the algal microhabitat, constituting 74.63% of the malacofauna recorded. The columbellid Parvanachis obesa(C. B. Adams, 1845 was the dominant species followed by the neritid Neritina virginea (Linnaeus, 1758 in both algae. In spite of the annual alternated succession of the algae species, at least 15 mollusc species are common for these algae. Furthermore, juveniles of P. obesa were recorded in both seasons, indicating a continuous reproduction. Possible reasons for difference in abundance, diversity and dominance of molluscs living on these algae are discussed. Both species of substrate-algae represent an important microhabitat for refuge, feeding and the reproduction of small-sized mollusc species during rainy and dry seasons.

Semi-automatic surface sediment sampling system - A prototype to be implemented in bivalve fishing surveys

Science.gov (United States)

Rufino, Marta M.; Baptista, Paulo; Pereira, Fábio; Gaspar, Miguel B.

2018-01-01

In the current work we propose a new method to sample surface sediment during bivalve fishing surveys. Fishing institutes all around the word carry out regular surveys with the aim of monitoring the stocks of commercial species. These surveys comprise often more than one hundred of sampling stations and cover large geographical areas. Although superficial sediment grain sizes are among the main drivers of benthic communities and provide crucial information for studies on coastal dynamics, overall there is a strong lack of this type of data, possibly, because traditional surface sediment sampling methods use grabs, that require considerable time and effort to be carried out on regular basis or on large areas. In face of these aspects, we developed an easy and un-expensive method to sample superficial sediments, during bivalve fisheries monitoring surveys, without increasing survey time or human resources. The method was successfully evaluated and validated during a typical bivalve survey carried out on the Northwest coast of Portugal, confirming that it had any interference with the survey objectives. Furthermore, the method was validated by collecting samples using a traditional Van Veen grabs (traditional method), which showed a similar grain size composition to the ones collected by the new method, on the same localities. We recommend that the procedure is implemented on regular bivalve fishing surveys, together with an image analysis system to analyse the collected samples. The new method will provide substantial quantity of data on surface sediment in coastal areas, using a non-expensive and efficient manner, with a high potential application in different fields of research.

Marine Bivalve Cellular Responses to Beta Blocker Exposures ...

Science.gov (United States)

β blockers are prescription drugs used for medical treatment of hypertension and arrhythmias. They prevent binding of agonists such as catecholamines to β adrenoceptors. In the absence of agonist induced activation of the receptor, adenylate cyclase is not activated which in turn limits cAMP production and protein kinase A activation, preventing increases in blood pressure and arrhythmias. After being taken therapeutically, commonly prescribed β blockers may make their way to coastal habitats via discharge from waste water treatment plants (WWTP) posing a potential risk to aquatic organisms. The aim of our research is to evaluate cellular responses of three commercially important marine bivalves - Eastern oysters, blue mussels and hard clams - upon exposure to two β blocker drugs, propranolol and metoprolol, and to find molecular initiating events (MIEs) indicative of the exposure. Bivalves were obtained from Narragansett Bay (Rhode Island, USA) and acclimated in the laboratory. Following acclimation, gills and hepatopancreas (HP) tissues were harvested and separately exposed to 0, 1, 10, 100 and 1000 ng/l of each drug. Tissues were bathed in 30 parts per thousand (ppt) filtered seawater, antibiotic mix, Leibovitz nutrient media, and the test drug. Exposures were conducted for 24 hours and samples were saved for cellular biomarker assays. A lysosomal destabilization assay, which is a marker of membrane damage, was also performed at the end of each exposure.

Evaluation of the effect of temperature, pH, and bioproduction on Hg concentration in sediments, water, molluscs and algae of the delta of the Ebro river.

Science.gov (United States)

Schuhmacher, M; Domingo, J L; Llobet, J M; Corbella, J

1993-01-01

The effects of temperature, pH, and bioproduction on mercury levels in sediments, water, molluscs and algae from the delta of the Ebro river (NE Spain) were determined in this study. Mercury concentrations were measured in a cold-vapor atomic absorption spectrophotometer. The ranges of mercury concentrations were the following: sediments, 0.014-0.185 microgram g-1; water, 0.001-0.018 microgram g-1; molluscs, 0.118-0.861 microgram g-1; and algae 0.008-0.026 microgram g-1. Although not statistically significant, a decrease in the pH of the water corresponded with a diminution in the content of mercury in sediments and molluscs, while the mercury levels in water and algae were lower in the areas with high levels of bioproduction. The concentrations of mercury in water significantly decreased with temperature. However, the differences with temperature of the mercury concentrations in sediments did not reach the level of significance. Consequently, water would not be an adequate indicator to determine the levels of mercury contamination, although both sediments and molluscs can be used for this purpose.

Distribution of organotin compounds in the bivalves of the Aegean Sea, Greece

NARCIS (Netherlands)

Chandrinou, S.; Pappas, K.; Nikolaou, A.; Stasinakis, A.S.; Wegener, J.W.M.; Alexandropoulos, Th.; Thomaidis, N.S.

2007-01-01

Five bivalve species - Mytilus galloprovinciallis (Mediterranean mussels), Venus gallina (stripped venus), Modiola barbatus L. (bearded horse mussels), Pecten jacobeus (scallops) and Callista chione (hard clams) - were collected from seven areas in Aegean Sea, Greece, between August 2001 and January

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

habitats. Study of the functional morphology of bivalve shells and comparison with extant relatives has resulted in a subdivision of the fauna into seven guilds and five habitats. The bivalve fauna represents a withinhabitat, time-averaged assemblage to which none of the species was introduced from...

Rodriguesic acids, modified diketopiperazines from the gastropod mollusc Pleurobranchus areolatus

Energy Technology Data Exchange (ETDEWEB)

Pereira, Fabio R.; Santos, Mario F.C.; Berlinck, Roberto G.S., E-mail: rgsberlinck@iqsc.usp.br [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Quimica; Williams, David E.; Andersen, Raymond J. [Departments of Chemistry and Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver (Canada); Padula, Vinicius [SNSB-Zoologische Staatssammlung München, München, Germany and Department Biology II and GeoBio-Center, Ludwig-Maximilians-Universität München, (Germany); Ferreira, Antonio G. [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Quimica

2014-04-15

In the present investigation, two specimens of the nudipleuran mollusc Pleurobranchus areolatus have shown to accumulate oxidized rodriguesin A derivatives. Rodriguesic acid presents a carboxylic acid replacing the terminal methyl group of the alkyl chain of rodriguesin A. A hydroxamate group was also present on the diketopiperazine moiety of a rodriguesic acid derivative. The structures of both rodriguesic acid and of rodriguesic acid hydroxamate have been established by analysis of spectroscopic data, including their absolute configuration. Two methyl esters of the rodriguesic acids have been isolated as major compounds, but were considered to be isolation artifacts. (author)

Rodriguesic acids, modified diketopiperazines from the gastropod mollusc Pleurobranchus areolatus

International Nuclear Information System (INIS)

Pereira, Fabio R.; Santos, Mario F.C.; Berlinck, Roberto G.S.; Padula, Vinicius; Ferreira, Antonio G.

2014-01-01

In the present investigation, two specimens of the nudipleuran mollusc Pleurobranchus areolatus have shown to accumulate oxidized rodriguesin A derivatives. Rodriguesic acid presents a carboxylic acid replacing the terminal methyl group of the alkyl chain of rodriguesin A. A hydroxamate group was also present on the diketopiperazine moiety of a rodriguesic acid derivative. The structures of both rodriguesic acid and of rodriguesic acid hydroxamate have been established by analysis of spectroscopic data, including their absolute configuration. Two methyl esters of the rodriguesic acids have been isolated as major compounds, but were considered to be isolation artifacts. (author)

Impact of an icy winter on the Pacific oyster (Crassostrea gigas Thunberg, 1793) populations in Scandinavia

DEFF Research Database (Denmark)

Strand, Åsa; Blanda, Elisa; Bodvin, Torjan

2012-01-01

The Pacific oyster (Crassostrea gigas) is an invasive species that has dispersed into Scandinavia during the last few decades. The objective of this study was to evaluate the effects of extreme winter conditions on the mortality of the Pacific oyster in Scandinavia. The study was done by compilin...

Development and distribution of the non-indigenous Pacific oyster (Crassostrea gigas) in the Dutch Wadden Sea

NARCIS (Netherlands)

Fey-Hofstede, F.E.; Dankers, N.M.J.A.; Steenbergen, J.; Goudswaard, P.C.

2010-01-01

Pacific oysters (Crassostrea gigas) were first observed in the Dutch Wadden Sea near Texel in 1983. The population increased slowly in the beginning but grew exponentially from the mid-1990s onwards, although now some stabilisation seems to be occurring. They occur on a variety of substrates such as

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.

Distribution of DTHS3 satellite DNA across 12 bivalve species Eva ...

Indian Academy of Sciences (India)

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In this work, characterization of DTHS3 satellite DNA was further expanded within the Class. Bivalvia. Monomer variants of DTHS3 satDNA were compared in 12 bivalve species belonging to two different Subclasses, Heterodonta and Pteriomorphia. This satDNA, whose age is estimated to a minimum of 516 Ma, ...

Postglacial floodings of the Marmara Sea: molluscs and sediments tell the story

Science.gov (United States)

Büyükmeriç, Yeşim

2016-08-01

The early Holocene marine flooding of the Black Sea has been the subject of intense scientific debate since the "Noah's Flood" hypothesis was proposed in the late 1990s. The chronology of the flooding is not straightforward because the connection between the Black Sea and the Mediterranean Sea involves the intermediate Marmara Sea Basin via two sills (Dardanelles and Bosphorus). This study explores the chronology of late Pleistocene-Holocene flooding by examining sedimentary facies and molluscs from 24 gravity cores spanning shelf to slope settings in the southern Marmara Sea Basin. A late Pleistocene Ponto-Caspian (Neoeuxinian) mollusc association is found in 12 of the cores, comprising 14 mollusc species and dominated by brackish (oligohaline-lower mesohaline) endemic taxa (dreissenids, hydrobiids). The Neoeuxinian association is replaced by a Turritella- Corbula association at the onset of the Holocene. The latter is dominated by marine species, several of which are known to thrive under dysoxic conditions in muddy bottoms. This association is common in early Holocene intervals as well as sapropel intervals in younger Holocene strata. It is an indicator of low-salinity outflows from the Black Sea into the Marmara Sea that drive stratification. A marine Mediterranean association (87 species) represents both soft bottom and hard substrate faunas that lived in well-ventilated conditions and upper mesohaline-polyhaline salinities (ca. 25 psu). Shallower areas were occupied by hard substrate taxa and phytopdetritic communities, whereas deeper areas had soft bottom faunas. The middle shelf part of the northern Gemlik Gulf has intervals with irregular and discontinuous sedimentary structures admixed with worn Neoeuxinian and euryhaline Mediterranean faunas. These intervals represent reworking events (slumping) likely related to seismic activity rooted in the North Anatolian Fault system. The core data and faunas indicate an oscillating postglacial sea-level rise and

Polymorphic microsatellite loci for two Atlantic oyster species: Crassostrea rhizophorae and C. gasar.

Science.gov (United States)

Cavaleiro, Nathalia P; Solé-Cava, Antonio M; Lazoski, Cristiano; Cunha, Haydée A

2013-12-01

Using a CA/CAA enriched library screening procedure, we isolated and characterised a total of seventeen polymorphic microsatellite loci for two species of Crassostrea with recognised economic importance. Eleven microsatellite loci were developed for C. rhizophorae, a Western Atlantic species for which no microsatellites were previously known. Another six loci were developed for C. gasar, a species that occurs on both sides of the South Atlantic, adding to the ten loci previously described for the species. The levels of polymorphism were estimated using 24 C. rhizophorae from Southeast Brazil (São Paulo) and 23 C. gasar individuals from North Brazil (Maranhão). The number of alleles per polymorphic locus varied from 3 to 27, and the observed and expected heterozygosities ranged between 0.174 and 0.958 and between 0.237 and 0.972 in C. rhizophorae and C. gasar, respectively. No linkage disequilibrium was found between any locus pair, and four of them exhibited deviations from Hardy-Weinberg expectations. Of the 17 loci developed, 8 cross-amplified in C. gigas and 13 in C. virginica. These markers are useful for evolution and population genetics studies of Crassostrea species and may provide fundamental data for the future cultivation of native oysters in Western Atlantic.

Isolation of living Algae growing in the shells of Molluscs and Barnacles with EDTA (ethylenediaminetetraacetic acid)

NARCIS (Netherlands)

Prud’homme van Reine, W.F.; Hoek, van den C.

1966-01-01

Several decalcifying mixtures or aqueous solutions of inorganic or organic acids are generally used for releasing algae growing in the shells of molluscs and barnacles, for instance dilute hydrochloric, nitric, citric, or acetic acid (4), a mixture of nitric acid, chromic acid and alcolhol (1),

A Guide to the Principal Marine Fouling Organisms, with Particular Reference to Cockburn Sound, W.A.,

Science.gov (United States)

1982-07-01

and crowned with long, feathery tentacles ( branchial filaments) which are used to draw food and oxygen from the water. The end of one filament is... branchial filaments. Tubes can reach 50 mm long and 0.5 mm diameter. Filograna can reproduce asexually with new individuals budded off parent worms and...the branchial crown of feeding tentacles seen in serpulids. Bivalves are the most significant of the fouling molluscs. The animal is laterally

Hatchery-scale trials using cryopreserved spermatozoa of black-lip pearl oyster, Pinctada margaritifera

OpenAIRE

Hui, Belinda; Vonau, Vincent; Moriceau, Jacques; Tetumu, Roger; Vanaa, Vincent; Demoy-schneider, Marina; Suquet, Marc; Le Moullac, Gilles

2011-01-01

Cryopreservation is a valuable tool for genetic improvement programs. Several bivalve mollusc species have already been the subject of such programs and the Tahitian black pearl oyster industry is now planning the development of selective breeding for desirable traits in Pinctada margaritifera. The ability to cryopreserve spermatozoa would, therefore, offer significant benefits to the cultured black pearl industry. Spermatozoa were cryopreserved with CPA 0.7 M trehalose in 0.8 M Me2SO and...

Response of an estuarine benthic community to application of the pesticide carbaryl and cultivation of Pacific oysters (Crassostrea gigas) in Willapa Bay, Washington.

Science.gov (United States)

Dumbauld, B R; Brooks, K M; Posey, M H

2001-10-01

Oyster culture operations on the West coast of North America have developed into complete farming operations for the introduced Japanese oyster, Crassostrea gigas, which now covers vast areas of the intertidal landscape, particularly in Washington State where the pesticide carbaryl has also been used to control burrowing thalassinid shrimp for more than 30 years. Field experiments were conducted to examine the effects of these habitat modifications on the benthic community in Willapa, Bay Washington (124 degrees 06'W,46 degrees 24'N) where 50% of the state's oyster production occurs. Results indicated that the primary long-term effect of carbaryl application was removal of the two species of thalassinid shrimp (Neotrypaea californiensis and Upogebia pugettensis), which dominated the community at the start of the experiment and clearly influenced community composition themselves. Small peracarid crustaceans like the amphipods Corophium acherusicum and Eohaustorius estuarius experienced the most significant short-term mortalities, but generally recruited back to treated sites within 3 months, and were often more abundant on treated than untreated sites 1 year after carbaryl application. Results for molluscs were mixed, with no significant effect on Macoma spp, but a significant effect on the commensal clam Crytomya californica and mixed results for the cockle Clinocardium nutalli. Polychaetes were the least susceptible to carbaryl and with the exception of a short-term effect on oligochaetes, no significant negative effects were observed. The addition of oysters did not affect the infaunal community in this study, however greater abundance of epifaunal organisms like mussels, scaleworms, and the amphipod Amphithoe valida, which builds tubes in algae attached to shells, was observed. Carbaryl, which is currently applied to roughly 242 ha (oyster culture operations like the addition of oysters themselves to a community often dominated by burrowing thalassinid shrimp

Middle to Late Ordovician faunal studies from central Australia and Tasmania during the Great Ordovician Biodiversification Event

DEFF Research Database (Denmark)

Jakobsen, Kristian Grube

A profound transformation of the marine biosphere took place during the Great Ordovician Biodiversification Event (GOBE), recognized as the longest interval of sustained biodiversification in the history of life. Successions through the Middle Ordovician Stairway Sandstone of the Amadeus Basin......, but the diversity is generally relatively low. The bivalves are the most dominant and diverse group in the central Australian fauna, whereas the brachiopods are the most dominant and diverse group in the Tasmanian fauna. Thirteen trilobite, five brachiopod, four conodont and 22 mollusc taxa have been documented......, but the preservation and low number of specimens prevent formal definition of additional new taxa. Although highly endemic at species level, the investigated brachiopod, trilobite and mollusc faunas display a high degree of overall similarity at generic level with Middle Ordovician faunas from North China. Other...

An investigation of green iridescence on the mollusc Patella granatina

Energy Technology Data Exchange (ETDEWEB)

Brink, D J; Berg, N G van der [Department of Physics, University of Pretoria, Pretoria 0002 (South Africa)

2005-01-21

In this paper we investigate the relatively rare phenomenon of iridescence on the outer surface of seashells (not the well known pearly inner surfaces). Using reflection spectroscopy and scanning electron microscopy we show that rows of iridescent green spots on the mollusc Patella granatina are caused by a thin-film stack buried about 100 {mu}m below the rough outer surface of the shell. The high-density layers in the stack seem to be made of crystalline aragonite, but according to Raman spectroscopy and ellipsometry measurements the low-density layers as well as the bulk of the shell wall are a mixture of porous aragonite and organic materials such as carotenoids.

Oxygen isotope fluctuations in a modern North Sea oyster (Crassostrea gigas) compared with annual variations in seawater temperature

DEFF Research Database (Denmark)

Ullmann, Clemens Vinzenz; Wiechert, Uwe; Korte, Christoph

2010-01-01

A total of 181 oxygen isotope values from sequential samples of the left shell of a modern Pacific Oyster (Crassostrea gigas) that lived on a sub-tidal oyster bank in the List Basin (North Sea, Germany) shows periodically varying values between + 1.3‰ and -2.5‰. In order to test whether these d18O...... fluctuations reflect seawater temperature changes, the isotope values of the shell were compared to actual seawater temperature variations from the region. C. gigas serves as an excellent proxy for temperature of palaeoseawater and the results show that the examined oyster precipitated its shell in d18O...... equilibrium with the ambient seawater. A cessation of the oyster shell calcification starts at water temperatures below 6 °C, at lower temperatures than previously thought for Crassostrea. For palaeoclimate investigations the termination of shell production is important because the lowest temperatures might...

Cuantificación de metales pesados en Anadara tuberculosa(Mollusca:bivalvia del estero Huaylá de Puerto Bolívar, por espectrofotometría de absorción atómica

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Collaguazo-Collaguazo, Yadira

2017-09-01

Full Text Available The presence of heavy metals in bivalve molluscs implies a serious problem for the consumers health of this type of food. Therefore, the objective of the present investigation was to determine the presence of heavy metals in Anadara tuberculosa, mollusc of commercial importance at Puerto Bolívar, Ecuador. Atomic absorption spectrophotometry was the method used to quantify the concentration of heavy metals. The concentration of six metals was determined: lead (Pb, arsenic (As, mercury (Hg, cadmium (Cd, chromium (Cr and cobalt (Co. The average values obtained, expressed in mg.kg-1 were: Pb (7.52 ± 0.46; As (1.55 ± 0.14; Hg (364.38 ± 91.39; Cd (1.68 ± 0.28; Cr (3,89 ± 1,82 and Co (2,71 ± 0,34 in A. tuberculosa The results show that Pb, As, Cd, and Hg exceed the maximum permissible limits, mercury exceeds by more than 100 times the limit value. The smaller size (3-4 cm studied mollusc, has the capacity to bioaccumulate higher concentration of Pb, Cd and Cr.

Seasonal variation in mitochondrial responses to cadmium and temperature in eastern oysters Crassostrea virginica (Gmelin) from different latitudes

International Nuclear Information System (INIS)

Cherkasov, A.S.; Taylor, C.; Sokolova, I.M.

2010-01-01

Cadmium (Cd) is an important environmental pollutant that can lead to impairment of cellular functions, energy misbalance and negatively impact survival in estuarine organisms including oysters. Like other marine bivalves, oysters can accumulate high Cd burdens in their tissues and are susceptible to the toxic effects of this metal. Presently, the factors that affect sensitivity to Cd toxicity and its variation in wild oyster populations are poorly understood. We analyzed geographical and seasonal variability of mitochondrial responses to elevated temperatures and Cd stress in eastern oysters Crassostrea virginica from populations adapted to different thermal regimes (subtropical Texas (TX), warm temperate North Carolina (NC) and cold temperate Washington (WA) areas). Seasonality had a strong effect on mitochondrial function in oysters from the two studied southern populations (TX and NC) but not in their northern (WA) counterparts, with decreased mitochondrial abundance and increased rates of mitochondrial proton leak in gill tissues of TX and NC oysters in summer. Compared to WA oysters, oysters from the two southern populations accumulated Cd faster in their tissues, and their mitochondria were more sensitive to Cd inhibition in resting and ADP-stimulated states at 20 and 28 o C. At 12 o C, inter-populational differences in Cd accumulation rates and sensitivity of mitochondrial respiration to Cd were not significant. Within each of the three studied populations, sensitivity of mitochondrial ADP-stimulated respiration to Cd inhibition increased with increasing temperatures (28 > 20 > 12 o C). This indicates that oysters from the two southern sites may be more vulnerable to Cd toxicity due to exposure to high environmental temperatures in summer, elevated rates of Cd accumulation and high intrinsic sensitivity of their mitochondria to Cd. This study suggests that data on sensitivity to pollutants obtained for one population of oysters should be extrapolated to

Seasonal variation in mitochondrial responses to cadmium and temperature in eastern oysters Crassostrea virginica (Gmelin) from different latitudes

Energy Technology Data Exchange (ETDEWEB)

Cherkasov, A.S. [Department of Biology, University of North Carolina at Charlotte, Charlotte, NC (United States); Taylor, C. [Department of Biology, University of North Carolina at Charlotte, Charlotte, NC (United States); Johnson C. Smith University, 100 Beatties Ford Rd., Charlotte, NC 28216 (United States); Sokolova, I.M., E-mail: isokolov@uncc.edu [Department of Biology, University of North Carolina at Charlotte, Charlotte, NC (United States)

2010-04-01

Cadmium (Cd) is an important environmental pollutant that can lead to impairment of cellular functions, energy misbalance and negatively impact survival in estuarine organisms including oysters. Like other marine bivalves, oysters can accumulate high Cd burdens in their tissues and are susceptible to the toxic effects of this metal. Presently, the factors that affect sensitivity to Cd toxicity and its variation in wild oyster populations are poorly understood. We analyzed geographical and seasonal variability of mitochondrial responses to elevated temperatures and Cd stress in eastern oysters Crassostrea virginica from populations adapted to different thermal regimes (subtropical Texas (TX), warm temperate North Carolina (NC) and cold temperate Washington (WA) areas). Seasonality had a strong effect on mitochondrial function in oysters from the two studied southern populations (TX and NC) but not in their northern (WA) counterparts, with decreased mitochondrial abundance and increased rates of mitochondrial proton leak in gill tissues of TX and NC oysters in summer. Compared to WA oysters, oysters from the two southern populations accumulated Cd faster in their tissues, and their mitochondria were more sensitive to Cd inhibition in resting and ADP-stimulated states at 20 and 28 {sup o}C. At 12 {sup o}C, inter-populational differences in Cd accumulation rates and sensitivity of mitochondrial respiration to Cd were not significant. Within each of the three studied populations, sensitivity of mitochondrial ADP-stimulated respiration to Cd inhibition increased with increasing temperatures (28 > 20 > 12 {sup o}C). This indicates that oysters from the two southern sites may be more vulnerable to Cd toxicity due to exposure to high environmental temperatures in summer, elevated rates of Cd accumulation and high intrinsic sensitivity of their mitochondria to Cd. This study suggests that data on sensitivity to pollutants obtained for one population of oysters should be

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

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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.

Climate change and body size shift in Mediterranean bivalve assemblages: unexpected role of biological invasions.

Science.gov (United States)

Nawrot, Rafał; Albano, Paolo G; Chattopadhyay, Devapriya; Zuschin, Martin

2017-08-16

Body size is a synthetic functional trait determining many key ecosystem properties. Reduction in average body size has been suggested as one of the universal responses to global warming in aquatic ecosystems. Climate change, however, coincides with human-enhanced dispersal of alien species and can facilitate their establishment. We address effects of species introductions on the size structure of recipient communities using data on Red Sea bivalves entering the Mediterranean Sea through the Suez Canal. We show that the invasion leads to increase in median body size of the Mediterranean assemblage. Alien species are significantly larger than native Mediterranean bivalves, even though they represent a random subset of the Red Sea species with respect to body size. The observed patterns result primarily from the differences in the taxonomic composition and body-size distributions of the source and recipient species pools. In contrast to the expectations based on the general temperature-size relationships in marine ectotherms, continued warming of the Mediterranean Sea indirectly leads to an increase in the proportion of large-bodied species in bivalve assemblages by accelerating the entry and spread of tropical aliens. These results underscore complex interactions between changing climate and species invasions in driving functional shifts in marine ecosystems. © 2017 The Author(s).

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

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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

Ecology of megabenthic bivalve communities from sandy beaches on the south coast of Portugal

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Marta M. Rufino

2010-03-01

Full Text Available Ecological aspects of 75 megabenthic bivalve species found on the south coast of Portugal (from Vila Real to Sagres were studied based on the information provided by seasonal bivalve surveys from 2000 to 2007 (8600 hauls, simultaneously using a razor shell dredge and a clam dredge. Of the 75 species identified, 36 occurred less than 30 times, and thus were considered rare in the area. The remaining 39 bivalves were analysed according to their occurrence, bathymetric distribution, geographic preferences, seasonal preferences, burying-depth, beach exposure and river mouth proximity. All species belonging to the Pharidae and Solenidae families (razor shells and most Tellinidae were significantly more frequent in the razor shell dredge (indicating deeper burying in the sediment, whilst the families Cardiidae and Donacidae were significantly more frequent in the clam dredge (indicating that these species are probably closer to the sediment surface. As for the season, most bivalve species occurred similarly in both seasons (19 sp; 49%, but a large proportion were more abundant during the autumn surveys (17 sp., 44%, whereas only three species were commoner during the spring surveys. Most species belonging to the families Cardiidae and Mactridae were commoner in the autumn surveys. The spatial distribution differed between species and cluster analysis identified four communities with greater geographic affinity. Species belonging to the family Cardiidae were preferably found in the western part (WB and the eastern part (S of the study area, whereas the families Donacidae, Mactridae and Tellinidae occurred mainly in the central area (EB and the eastern (S coastal sectors. Overall, shallower species (modal depth at 3-6 m showed greater occurrences and abundances than the deeper ones, and the depth pattern observed did not change between seasons. Donacidae and Mactridae (except Mactra glauca were represented essentially by shallow species, whereas

Traditional utilization and biochemical composition of six mollusc shells in Nigeria

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Ademolu Kehinde O.

2015-06-01

Full Text Available The shells of molluscs protect them from physical damage, predators and dehydration. We studied various local uses of shells and their biochemical properties in Abeokuta, Nigeria. A standard structured questionnaire about use was applied to 100 snail and herb sellers and shells from 120 adult individuals of Archachatina marginata, Achatina achatina, Achatina fulica, Littorina littorea, Meretrix lusoria and Merceneria mercenaria were evaluated for their mineral components (Ca2+, Fe2+, Mg2+, Na+, Zn+, P+, K+ and proximate composition (crude protein, ash, fibre, crude fat and carbohydrate using standard methods. Properties against fungi and bacteria isolates were also tested. These shells are used for bleaching, brushing, abrasion and others. The weight of the shells varied from 0.5g (L. littorea to 25.00g (A. marginata and thickness from 0.46mm in M .lusoria to 5.35mm in M. mercenaria. We found no inhibitory effect against fungi and bacterial isolates. The molluscs are high in carbohydrates (83.54-92.76g/100g and low in protein (0.16-0.38g/100g. The fat content ranged between 0.42g/100g and 0.82g/100g, and ash between 2.14g/100g and 9.45g/100g. Ca2+ was the most abundant (10.25-96.35mg/g while K+ was the least abundant (0.3-0.7mg/g (p<0.05. Active ingredients of these shells can be used in the feed and construction industries.

Detection of Perkinsus marinus in the oyster Crassostrea rhizophorae in southern Bahia by proteomic analysis

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Thiago Ramos Pinto

2017-01-01

Full Text Available This study reports the presence of the pathogen Perkinsus marinus, notifiable to the World Organization for Animal Health (Office International des Èpizooties = OIE in the oyster Crassostrea rhizophorae in southern Bahia via proteomic analysis. We analyzed Crassostrea brasiliana from a long-line cultivation system and C. rhizophorae from an adjacent mangrove in Porto do Campo, Camamu Bay, Bahia, Brazil. The collections (n = 100 were performed in October 2012. In the laboratory, the oysters were measured and opened to remove the meat, which was steeped in dry ice. For extraction of proteins, adaptation of a protocol used for mussels was used, after which separation in the first dimension was taken by isoelectric focusing (IEF. The peptides were transferred to a Mass Spectrometer. The obtained spectra were analyzed with the ProteinLynx Global Server 4.2 software tool and also by MASCOT (Matrix Science and compared to the databases of the SWISSPROT and NCBI, respectively. The identification was evidenced by beta-tubulin, Perkinsus marinus ATCC 50983 and protein homology code in the database NCBI = gi | 294889481. This is the first record of P. marinus in Bahia and the fourth in Brazil.

Light indirectly mediates bivalve habitat modification and impacts on seagrass

DEFF Research Database (Denmark)

Castorani, Max C. N.; Glud, Ronnie; Hasler-Sheetal, Harald

2015-01-01

Environmental context may influence the sign, strength, andmechanisms of species interactions but few studies have experimentally tested the potential for abiotic conditions to mediate interactions through multiple cooccurring stress pathways. Abiotic conditionsmay mediate species interactions...... by directly or indirectly influencing the effects of habitat-modifying organisms that are capable of simultaneously ameliorating and exacerbating multiple stressors. Itwas hypothesized that light availability changes seagrassmetabolismand thereby indirectly regulates bivalve habitat modification...

PARASITIC AND SYMBIOTIC FAUNA IN OYSTERS (CRASSOSTREA VIRGINICA) AND MUD CRABS (PANOPEUS SPP.) FROM THE CALOOSAHATCHEE ESTUARY, FLORIDA, USA.

Science.gov (United States)

Volety, Aswani K., S. Greg Tolley and James T. Winstead. 2002. Parasitic and Symbiotic Fauna in Oysters (Crassostrea virginica) and Mud Crabs (Panopeus spp.) from the Caloosahatchee Estuary, Florida, USA (Abstract). Presented at the 4th International Conference on Molluscan Shell...

Ostreid herpesvirus 1 infection among Pacific oyster (Crassostrea gigas) Spat: relevance of water temperature to virus replication and circulation prior to the onset of mortality.

Science.gov (United States)

Renault, Tristan; Bouquet, Anne Lise; Maurice, Julien-Thomas; Lupo, Coralie; Blachier, Philippe

2014-09-01

A number of bivalve species worldwide, including the Pacific oyster, Crassostrea gigas, have been affected by mass mortality events associated with herpesviruses, resulting in significant losses. A particular herpesvirus was purified from naturally infected larval Pacific oysters, and its genome was completely sequenced. This virus has been classified as Ostreid herpesvirus 1 (OsHV-1) within the family Malacoherpesviridae. Since 2008, mass mortality outbreaks among C. gigas in Europe have been related to the detection of a variant of OsHV-1 called μVar. Additional data are necessary to better describe mortality events in relation to environmental-parameter fluctuations and OsHV-1 detection. For this purpose, a single batch of Pacific oyster spat was deployed in 4 different locations in the Marennes-Oleron area (France): an oyster pond ("claire"), a shellfish nursery, and two locations in the field. Mortality rates were recorded based on regular observation, and samples were collected to search for and quantify OsHV-1 DNA by real-time PCR. Although similar massive mortality rates were reported at the 4 sites, mortality was detected earlier in the pond and in the nursery than at both field sites. This difference may be related to earlier increases in water temperature. Mass mortality was observed among oysters a few days after increases in the number of PCR-positive oysters and viral-DNA amounts were recorded. An initial increment in the number of PCR-positive oysters was reported at both field sites during the survey in the absence of significant mortality. During this period, the water temperature was below 16°C. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Growth of Crassostrea gasar cultured in marine and estuary environments in Brazilian waters

OpenAIRE

Lopes,Gustavo Ruschel; Gomes,Carlos Henrique Araujo de Miranda; Tureck,Cláudio Rudolfo; Melo,Claudio Manuel Rodrigues de

2013-01-01

The objective of this work was to evaluate the growth of the mangrove oyster Crassostrea gasar cultured in marine and estuarine environments. Oysters were cultured for 11 months in a longline system in two study sites - São Francisco do Sul and Florianópolis -, in the state of Santa Catarina, Southern Brazil. Water chlorophyll-α concentration, temperature, and salinity were measured weekly. The oysters were measured monthly (shell size and weight gain) to assess growth. At the end of the...

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

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...... and ecological systems, marine regulators require an ecosystem-based decision framework that structures and integrates the relationships between these systems and facilitates communication of aquaculture–environment interactions and policy-related developments and decisions. The Drivers-Pressures-State Change-Impact-Response...

Vodní malakofauna dolního toku Lužnice se zaměřením na stav populace velevruba tupého (Unio crassus Aquatic molluscan fauna of the lower part of the Lužnice River (South Bohemia, Czech Republic with focus on the population of Unio crassus

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Luboš Beran

2012-02-01

Full Text Available This paper presents results of a malacological survey of the Lužnice River in ca 70 km long stretch between the inflow of its main tributary the Nežárka River in Veselí nad Lužnicí and its confluence with the Vltava River in Southern Bohemia (Czech Republic. Thirty-one species of aquatic molluscs (19 gastropods, 12 bivalves representing 40% of freshwater molluscan fauna of the Czech Republic were found at 15 sites. Differences of molluscan assemblages upstream and downstream of Tábor town were probably caused by different characters of the watercourse. The occurrence of rare bivalve Pseudanodonta complanata was confirmed. On the other hand, two non-native species Physella acuta and Sinanodonta woodiana were recorded. The research was preferentially focused on the population of the endangered bivalve Unio crassus. Its occurrence was confirmed at 8 from 15 sites under study but altogether only 31 individuals were found. Less than four specimens were found at particular sites but one.

Cellular Responses to Beta Blocker Exposures in Marine ...

Science.gov (United States)

β blockers are prescription drugs used for medical treatment of hypertension and arrhythmias. They prevent activation of adenylate cyclase and increases in blood pressure by limiting cAMP production and protein kinase A activation. After being taken therapeutically, β blockers may make their way to coastal habitats via discharge from waste water treatment plants, posing a potential risk to aquatic organisms. The aim of our research is to evaluate cellular biomarkers of β blocker exposure using two drugs, propranolol and metoprolol, in three commercially important marine bivalves -Crassostrea virginica, Mytilus edulis and Mercenaria mercenaria. Bivalves were obtained from Narragansett Bay (Rhode Island, USA) and acclimated in the laboratory. Following acclimation, gills and hepatopancreas tissues were harvested and separately exposed to 0, 1, 10, 100 and 1000 ng/l of each drug for 24 hours. Samples were preserved for cellular biomarker assays. Elevated cellular damage and changes in enzymatic activities were noted at environmentally relevant concentrations, and M. mercenaria was found to be the most sensitive bivalve out of the three species tested. These studies enhance our understanding of the potential impacts of commonly used prescription medication on organisms in coastal ecosystems, and demonstrate that filter feeders such as marine bivalves may serve as good model organisms to examine the effects of water soluble drugs. Evaluating a suite of biomarkers

Are the Traditional Medical Uses of Muricidae Molluscs Substantiated by Their Pharmacological Properties and Bioactive Compounds?

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Kirsten Benkendorff

2015-08-01

Full Text Available Marine molluscs from the family Muricidae hold great potential for development as a source of therapeutically useful compounds. Traditionally known for the production of the ancient dye Tyrian purple, these molluscs also form the basis of some rare traditional medicines that have been used for thousands of years. Whilst these traditional and alternative medicines have not been chemically analysed or tested for efficacy in controlled clinical trials, a significant amount of independent research has documented the biological activity of extracts and compounds from these snails. In particular, Muricidae produce a suite of brominated indoles with anti-inflammatory, anti-cancer and steroidogenic activity, as well as choline esters with muscle-relaxing and pain relieving properties. These compounds could explain some of the traditional uses in wound healing, stomach pain and menstrual problems. However, the principle source of bioactive compounds is from the hypobranchial gland, whilst the shell and operculum are the main source used in most traditional remedies. Thus further research is required to understand this discrepancy and to optimise a quality controlled natural medicine from Muricidae.

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

Science.gov (United States)

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

2016-01-21

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

Characterizing Photosymbiosis Between Fraginae Bivalves and Symbiodinium Using Phylogenetics and Stable Isotopes

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Jingchun Li

2018-04-01

Full Text Available Photosymbiotic associations between heterotrophic hosts and photosynthetic algae play crucial roles in maintaining the trophic and structural integrity of coral reef ecosystems. The marine bivalve subfamily Fraginae contains both non-symbiotic and photosymbiotic lineages, making it an ideal comparative system to study the origin and evolutionary adaptations of photosymbiosis. The symbiotic species exhibit unique morphological adaptations to photosymbiosis. However, the basic biology of these photosymbiotic relationships, such as symbiont diversity and nutritional benefits, has not been thoroughly characterized. In this study, we examined the general morphology of four Fraginae species occupying different depths (0–10 m: Corculum cardissa, Fragum fragum, Fragum scruposum, and Fragum sueziense. Abundant symbionts were found in the mantle, gill, and part of the foot, contained in tubular networks within host tissues. We used molecular phylogenetics to investigate the algal symbiont community of these Fraginae species. Results showed that symbionts from all four species are dinoflagellates belonging to the Symbiodinium clade C and we did not detect any host-specific or geographic-specific genetic structures within the symbionts. We also used stable carbon isotope analyses to examine whether the cockles are directly utilizing photosynthetically derived carbon sources. All species show less depleted 13C compared to filter-feeding bivalves, suggesting at least part of their organic carbon is derived directly from the symbionts. However, 13C depletion of Fragum sueziense collected from deeper habitats are less distinguishable from filter-feeding bivalves. This indicates that species in deeper habitats may rely less on photosymbiosis due to the reduced light availability. Given that the symbiotic fragines exhibit varying morphologies, habitats, and utilization of symbiont photosynthesis, the subfamily represents an ideal model system to study

Pearl aquaculture-profitable environmental remediation?

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Gifford, S; Dunstan, R H; O'Connor, W; Roberts, T; Toia, R

2004-02-05

Bivalve molluscs are filter feeders, with pearl oysters able to filter water at rates up to 25 lh(-1)g(-1) of dry wt. tissue. Since this process leads to rapid bioaccumulation of recalcitrant pollutants such as heavy metals, organochlorine pesticides and hydrocarbons from impacted sites, it has prompted the widespread use of molluscs as biomonitors to quantify levels of marine pollution. This paper proposes pearl oyster deployment as a novel bioremediation technology for impacted sites to remove toxic contaminants, reduce nutrient loads and lower concentrations of microbial pathogens. Estimates extrapolated from the literature suggest that a modest pearl oyster farm of 100 t oyster material per year could remove 300 kg heavy metals plus 24 kg of organic contaminants via deposition into the tissue and shell. Furthermore, it was estimated that up to 19 kg of nitrogen may be removed from the coastal ecosystem per tonne of pearl oyster harvested. Pearl oysters are also likely to filter substantial amounts of sewage associated microbial pathogens from the water column. Method of cultivation and site selection are the key to minimising negative environmental impacts of bivalve cultivation. Deployment of oysters at sites with high nutrient and contaminant loadings would be advantageous, as these compounds would be removed from the ecosystem whilst generating a value-added product. Future potential may exist for harvesting bio-concentrated elements for commercial production.

High pressure processing of bivalve shellfish and HPP's potential use as a virus intervention

Science.gov (United States)

Bivalve shellfish readily bioconcentrate pathogenic microbes and substance, such as algal and dinoflagulate toxins, fecal viruses and bacteria, and naturally present vibrio bacteria. High pressure processing (HPP) is currently used as an intervention for Vibrio vulnificus bacteria within molluscan ...

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 (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.

Behavior of pathogenic bacteria in the oyster, Crassostrea commercialis, during depuration, re-laying, and storage.

OpenAIRE

Son, N T; Fleet, G H

1980-01-01

Oysters (Crassostrea commercials) harvested from major cultivation areas within the state of New South Wales, Australia, were commonly contaminated with low levels of the food-poisoning organisms Bacillus cereus, Clostridium perfringens, and Vibrio parahaemolyticus. Salmonella was found in oysters on only one occasion. These bacteria were cleansed from oysters during oyster purification by re-laying in a non-polluted waterway. Oysters were laboratory contaminated to levels in excess 1,000 cel...

PROGRESSION OF DISEASES CAUSED BY THE OYSTER PARASITES, PERKINSUS MARINUS AND HAPLOSPORIDIUM NELSONI, IN CRASSOSTREA VIRGINICA ON CONSTRUCTED INTERTIDAL REEFS

Science.gov (United States)

The progression of diseases caused by the oyster parasites, Perkinsus marinus and Haplosporidium nelsoni, were evaluated by periodic sampling (May 1994-Dec. 1995) of oysters, Crassostrea virginica, that set on an artificial reef located in the Piankatank River, Virginia, in Augus...

Biochemical and behavioural responses of the endobenthic bivalve Scrobicularia plana to silver nanoparticles in seawater and microalgal food.

Science.gov (United States)

Buffet, Pierre-Emmanuel; Pan, Jin-Fen; Poirier, Laurence; Amiard-Triquet, Claude; Amiard, Jean-Claude; Gaudin, Pierre; Risso-de Faverney, Christine; Guibbolini, Marielle; Gilliland, Douglas; Valsami-Jones, Eugenia; Mouneyrac, Catherine

2013-03-01

Because of their bactericidal effects, Ag nanoparticles (Ag NPs) have promising industrial development but could lead to potential ecological risks. The aim of this study was to examine the uptake and effect of silver (soluble or as lactate Ag NPs of 40 nm) at low concentrations (10 μg L(-1)) in the endobenthic bivalve Scrobicularia plana exposed, for 14 days, directly (water) or via the diet (microalgae). The stability of Ag NPs in seawater was examined using dynamic light scattering. Release of soluble Ag from Ag NPs in the experimental media was quantified by using diffusive gradient in thin film. Bioaccumulation of Ag in bivalves was measured by electrothermal atomic absorption spectrometry. Behavioural and biochemical biomarkers were determined in bivalves. Aggregation of Ag NPs and the release of soluble Ag from Ag NPs were observed in the experimental media. For both forms of Ag, bioaccumulation was much more important for waterborne than for dietary exposure. The response of oxidative stress biomarkers (catalase, glutathion S-transferase, superoxide dismutase) was more important after dietary than waterborne exposure to Ag (soluble and NPs). These defences were relatively efficient since they led to a lack of response of damage biomarkers. Burrowing was not affected for bivalves exposed directly or through the diet to both Ag forms but feeding behaviour was impaired after 10 days of dietary exposure. Since no differences of responses to Ag either soluble or nanoparticulate were observed, it seems that labile Ag released from Ag NPs was mainly responsible for toxicity. Copyright © 2012 Elsevier Inc. All rights reserved.

The effect of submarine thermal springs of Doğanbey Cape (Seferihisar - İzmir on foraminifer, ostracod and mollusc assemblages

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Engin MERİÇ

2017-12-01

Full Text Available The aim of this study was to fi gure out the effects of the submarine hot water springs located on the coast of Doğanbey Cape (north of Kuşadası Bay on various micro- and macrofaunal assemblages living around these springs. Young sediment samples were collected from different depths at 15 stations. The benthic foraminifer, ostracod and mollusc faunas were investigated. 35 genera and 61 species of benthic foraminifers, 16 genera and 20 species of ostracods and 14 genera and 15 species of molluscs were identifi ed. Typical Aeegan foraminifer fauna was found to be dominant. Besides, individuals with colored tests or abnormal morphology, as well as alien species, which are frequently observed on the Aegean coasts were also observed in the study area. The foraminifer, ostracod and mollusc species also constituted typical Aegean fauna. It is known that the ecological conditions experienced of the Amphistegina lobifera Larsen individuals in typical Aegean benthic foraminifer assemblage have an effect on the abundance distribution. Ideal conditions for Amphistegina lobifera Larsen was found to be 18.00-32.00 m depth range and 19-20oC temperatures. CTD conductivity values gradually increased near to the hot water spring but a decrease in the number of individuals were observed. Chemical analyzes in sediment samples were performed with X-Ray Fluorescence Analysis Spectrometer (WDXRF. Heavy metal ingredients (Cr, Mn, Co, Ni, Cu, Zn and Pb of the sediments were evaluated, concentrations were recorded as Cr>Ni>Mn in samples DB1-DB6 and also in DB15; Mn>Cr>Ni in DB8-DB11 and DB13-DB14; Cr>Mn>Ni in DB7 and in DB12. The radioactive elements U and Th were found to be high in DB9, DB10 and DB11. The chemical and radioactive properties of the sediments were observed to affect the tests of benthic foraminifers, where as no such effect was found on ostracod and mollusc tests.

[Nutrition and biological value of food parts of a trade bivalve mollusk Anadara broughtoni].

Science.gov (United States)

Tabakaeva, O V; Tabakaev, A V

2015-01-01

Currently, the human diet includes different new products of seafishing, including non-fish--bivalves and gastropods, holothurias, echinoderms, jellyfishes that demands careful studying of their chemical composition. The purpose of the study was to determine the nutritional and biological value of all soft parts of the burrowing bivalve MOLLUSK Anadara broughtoni from the Far East region. It was established thatfood parts of a bivalve were significantly flooded (water content--73.5-84.2%), with the minimum water content in the adductor and maximum in the mantle. Dry solids are presented by organic (89-93%) and mineral (7-11%) components. Organic components consist of protein (14.6-20.7%), lipids (1.8-2.3%), carbohydrates (2.1-2.6%). The analysis of amino-acid composition of proteins of food parts of the mollusk of Anadara broughtonishowed the presence of all essential amino acids with slight differences in their content depending on the localization of the protein. All edible parts have tryptophan as the limiting amino acid. Muscle proteins have maximum level of lysine, methionine, cysteine, phenylalanine and tyrosine; mantle proteins--leucine, isoleucine and threonine; adductor proteins--valine, phenylalanine, tyrosine, methionine and cysteine. Predominant nonessential amino acids forproteins of all food pieces are glycine, aspartic acid, glutamic acid, arginine. The coefficient of amino-acid score differences of adductor protein (31.7%) is less than the same of cloak by 3.7%. The indicator "biological value" is maximal for adductor (68.3%), but the differenceformuscle is only 0.83%. Mantle proteins are characterized by minimum biological value (64.6%). The coefficient of utility of amino acid composition of protein is maximalfor muscle (57.83%), and values for a cloak and an adductor differ slightly (55.81 and 55.96%). Taurine content in food parts of a mollusk Anadara broughtoni is rather high compared to with other bivalve mollusks of the Far East region

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

International Nuclear Information System (INIS)

Basallote, M. Dolores; Rodríguez-Romero, Araceli; De Orte, Manoela R.; Del Valls, T. Ángel; Riba, Inmaculada

2015-01-01

Highlights: • Short-term tests using juveniles of bivalves to study the effects of CO 2 dissolved. • CO 2 causes effects if the threshold concentration of the organism is overlapped. • Flows of escaped CO 2 would affect the geochemical composition of sediment–seawater. • CO 2 -induced acidification would affect differently to marine sediment toxicity. - Abstract: The effects of the acidification associated with CO 2 leakage from sub-seabed geological storage was studied by the evaluation of the short-term effects of CO 2 -induced acidification on juveniles of the bivalve Ruditapes philippinarum. Laboratory scale experiments were performed using a CO 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 2 and the dissolved metal concentrations (Zn and Fe) were linked with the mortality of the exposed bivalves

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

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

Měkkýši Národní přírodní rezervace Soos Molluscs (Mollusca of the Soos National Nature Reserve

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Jitka Horáčková

2012-12-01

Full Text Available The Soos National Nature Reserve nearby Františkovy Lázně Town (Western Bohemia, Czech Republic is a spectacular peatbog site with the occurrence of fens on numerous mineral spring effluents, emanations of pure carbon dioxide in mofettes (i.e. false mud volcanoes, parts with saltwater wetlands, and diatomite mantel in its central part. These natural conditions affect general character of all habitats, vegetation and malacocoenoses in the reserve. Altogether, 31 mollusc species were found there, but only two of them are considered as near threatened (Pisidium obtusale and Vertigo substriata. The majority of recorded assemblage was composed of common and generalist mollusc species.

Status of the Pacific Oyster Crassostrea gigas (Thunberg, 1793) in the western Limfjord, Denmark – Five years of population development

DEFF Research Database (Denmark)

Groslier, Tilde; Christensen, Helle Torp; Davids, Jens

2014-01-01

The Pacific oyster, Crassostrea gigas, was introduced into the Netherlands in 1964 for aquaculture purposes and has since spread extensively in Northern European waters. Eight locations in the western part of the Limfjord, Denmark, first sampled in 2006 were revisited in 2011, to determine how...

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.

New trends in important diseases affecting the culture of fish and molluscs in the ICES area 2002-2015

DEFF Research Database (Denmark)

Alfjorden, Anders; Areskog, Marlene; Bruno, David

The ICES Working Group on Pathology and Diseases of Marine Organisms (WGPDMO) provides annual reviews of national reports on the disease status of wild and farmed fish and molluscs in the ICES area. In 2004, the group published a first report collating this information from 1998-2002. This second...

The evolution of mollusc shells.

Science.gov (United States)

McDougall, Carmel; Degnan, Bernard M

2018-05-01

Molluscan shells are externally fabricated by specialized epithelial cells on the dorsal mantle. Although a conserved set of regulatory genes appears to underlie specification of mantle progenitor cells, the genes that contribute to the formation of the mature shell are incredibly diverse. Recent comparative analyses of mantle transcriptomes and shell proteomes of gastropods and bivalves are consistent with shell diversity being underpinned by a rapidly evolving mantle secretome (suite of genes expressed in the mantle that encode secreted proteins) that is the product of (a) high rates of gene co-option into and loss from the mantle gene regulatory network, and (b) the rapid evolution of coding sequences, particular those encoding repetitive low complexity domains. Outside a few conserved genes, such as carbonic anhydrase, a so-called "biomineralization toolkit" has yet to be discovered. Despite this, a common suite of protein domains, which are often associated with the extracellular matrix and immunity, appear to have been independently and often uniquely co-opted into the mantle secretomes of different species. The evolvability of the mantle secretome provides a molecular explanation for the evolution and diversity of molluscan shells. These genomic processes are likely to underlie the evolution of other animal biominerals, including coral and echinoderm skeletons. This article is categorized under: Comparative Development and Evolution > Regulation of Organ Diversity Comparative Development and Evolution > Evolutionary Novelties. © 2018 Wiley Periodicals, Inc.

Zoochorous dispersal of freshwater bivalves: an overlooked vector in biological invasions?

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Coughlan Neil E.

2017-01-01

Full Text Available Vectors that underpin the natural dispersal of invasive alien species are frequently unknown. In particular, the passive dispersal (zoochory of one organism (or propagule by another, usually more mobile animal, remains poorly understood. Field observations of the adherence of invasive freshwater bivalves to other organisms have prompted us to assess the importance of zoochory in the spread of three prolific invaders: zebra mussel Dreissena polymorpha; quagga mussel Dreissena bugensis; and Asian clam Corbicula fluminea. An extensive, systematic search of the literature was conducted across multiple on-line scientific databases using various search terms and associated synonyms. In total, only five publications fully satisfied the search criteria. It appears that some fish species can internally transport viable adult D. polymorpha and C. fluminea specimens. Additionally, literature indicates that veligers and juvenile D. polymorpha can adhere to the external surfaces of waterbirds. Overall, literature suggests that zoochorous dispersal of invasive bivalves is possible, but likely a rare occurrence. However, even the establishment of a few individuals (or a single self-fertilising C. fluminea specimen can, over-time, result in a substantial population. Here, we highlight knowledge gaps, identify realistic opportunities for data collection, and suggest management protocols to mitigate the spread of invasive alien species.

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

Energy Technology Data Exchange (ETDEWEB)

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

2010-11-15

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

Detection limits by EPR spectroscopy of cumulated doses ionizing radiations in molluscs shells

International Nuclear Information System (INIS)

Ostrowski, K.; Burlinska, G.; Dziedzic-Goclawska, A.; Stachowicz, W.; Michalik, J.; Sadlo, J.

1997-01-01

The exposure of waters to ionizing radiation from radionuclides stored in concrete containers or freed in nuclear accidents or underwater eruption might be difficult to be proved, when currents, rains, exchange of water displace sand soils or rocks in the bottom. Ionizing radiation evokes stable paramagnetic centers in the crystalline lattice of mineral components in bones as well as in exoskeletons of most molluscs, which are detected by the EPR spectroscopy and could be used as an indicator of the exposure to the action of radiation during prolonged period of time. (authors)

Optimizing a method for detection of hepatitis A virus in shellfish and study the effect of gamma radiation on the viral genome

International Nuclear Information System (INIS)

Amri, Islem

2008-01-01

Our work was aimed at detecting the hepatitis A virus (HAV) in bivalve mollusc collected from five shellfish harvesting areas and from a coastal region in Tunisia using RT-Nested-PCR and studying the effect of gamma radiation on HAV genome. Two methods used to recover HAV from mollusc flesh and two methods of extraction of virus RNA were compared in order to determine the most sensitive method. Glycine extraction and extraction of virus RNA using proteinase K were more convenient and then used in this study for detection of HAV in shellfish. The results of molecular analyses: RT-Nested-PCR using primers targeted at the P1 region revealed that 28 % of the samples were positive for HAV. Doses of gamma irradiation ranging between 5 to 30 kGy were used to study the effect of this radiation on HAV genome after the contamination of mollusc flesh with suspension of HAV (derived from stool specimens). HAV specific genomic band was observed for doses between 5 to 20 kGy. We didn't detect HAV genome with doses 25 and 30 kGy. (Author)

Impact of seawater carbonate chemistry on the calcification of marine bivalves

OpenAIRE

Thomsen Jörn; Haynert Kristin; Wegner K Mathias; Melzner Frank

2015-01-01

Bivalve calcification, particular of the early larval stages is highly sensitive to the change of ocean carbonate chemistry resulting from atmospheric CO2 uptake. Earlier studies suggested that declining seawater [CO32−] and thereby lowered carbonate saturation affect shell production. However, disturbances of physiological processes such as acid-base regulation by adverse seawater pCO2 and pH can affect calcification in a secondary fashion. In order to determine the e...

On the safe of pesticides in controlling the terrestrial mollusc pests

Directory of Open Access Journals (Sweden)

A. Panigrahi

1993-06-01

Full Text Available The preferred food items of the slugs Laevicaulis alte and the snails Achatina fulica were used to prepare 'poison baits'by injecting the pesticides 'Rogor'and 'Nuvan'to kill these mollusc pests. The 'poison baits'prepared with Thrichosanthes dioica and Lycopersicum esculentum were accepted by 100% individuals of both the species irrespective of the pesticides used. In all cases the slug and the snail individuals died within a considerable length of time following consuption of the bait. The importance of using 'poison bait'lies not only with the sure success in killing the pests but also with the 'safe use'of toxic materials in order to avoid environmental hazards.

Reproductive investment in the intertidal bivalve Macoma balthica

Science.gov (United States)

Honkoop, P. J. C.; Van der Meer, J.; Beukema, J. J.; Kwast, D.

1999-05-01

Bivalve eggs generally contain large amounts of lipids which, in comparison with proteins and carbohydrates, have high energy contents and are thus costly in energetic terms. As lipid contents vary between species, comparisons of reproductive investments should not only include numbers and sizes of eggs, but also their energy content. We estimated the investment in egg material of mature females of the Baltic tellin Macoma balthica (L.) in terms of both mass and energy content. All mass below a minimum body mass (below which no eggs are produced) was defined as structural mass. This threshold amounts to a body mass index (BMI) of 5.6 (ash-free dry mass per cubic shell length in mg cm -3). More than half (55%) of the mass above the structural mass was invested in egg material and 45% in extra somatic tissue and tissue for production and storage of gametes. This means that the amount of eggs spawned ranged from 0 (at BMI = 5.6 mg cm -3) to 33% of the total ash-free dry mass (at a high BMI value of 14 mg cm -3). Eggs contained a relatively large amount of lipids, about 30% of their ash-free dry mass, whereas non-egg material contained only about 7% lipids. Eggs of two other bivalves in the Wadden Sea, the cockle Cerastoderma edule and the mussel Mytilus edulis, were smaller and contained only about 11% and 20% lipids, respectively. Energy content of M. balthica eggs amounted to ˜0.006 J, in the other two species to ˜0.002 J. The function of the more expensive eggs in M. balthica may be related to its early spawning in spring, causing slower larval development until first feeding.

Predation on intertidal mussels: Influence of biotic factors on the survival of epibenthic bivalve beds

NARCIS (Netherlands)

Waser, A.M.

2018-01-01

Coastal areas are amongst the most productive ecosystems in the world. Important components of these coastal areas are reef-forming bivalves such as mussels and oysters, as they have important facilitating effects on many associated organisms through the provision of substratum,

The lunar-tide cycle viewed by crustacean and mollusc gatherers in the State of Paraíba, Northeast Brazil and their influence in collection attitudes

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Alves Rômulo RN

2006-01-01

Full Text Available Abstract Traditional human communities have a wide knowledge of their environment. Collection of animals in estuarine and coastal areas are directly influenced by tidal cycles. The aim of this study is to evaluate the understanding of the tides associated with the lunar cycle held by people who gather crustaceans and molluscs in the State of Paraiba. The empirical knowledge of 20 crab gatherers and 30 mollusc gatherers was recorded through open interviews and structured questionnaires. The results showed that the gatherers have an accurate comprehension of tidal phenomenon based on their exploitation of natural resources, which perpetuates through generations.

Sodium provides unique insights into transgenerational effects of ocean acidification on bivalve shell formation.

Science.gov (United States)

Zhao, Liqiang; Schöne, Bernd R; Mertz-Kraus, Regina; Yang, Feng

2017-01-15

Ocean acidification is likely to have profound impacts on marine bivalves, especially on their early life stages. Therefore, it is imperative to know whether and to what extent bivalves will be able to acclimate or adapt to an acidifying ocean over multiple generations. Here, we show that reduced seawater pH projected for the end of this century (i.e., pH7.7) led to a significant decrease of shell production of newly settled juvenile Manila clams, Ruditapes philippinarum. However, juveniles from parents exposed to low pH grew significantly faster than those from parents grown at ambient pH, exhibiting a rapid transgenerational acclimation to an acidic environment. The sodium composition of the shells may shed new light on the mechanisms responsible for beneficial transgenerational acclimation. Irrespective of parental exposure, the amount of Na incorporated into shells increased with decreasing pH, implying active removal of excessive protons through the Na + /H + exchanger which is known to depend on the Na + gradient actively built up by the Na + /K + -ATPase as a driving force. However, the shells with a prior history of transgenerational exposure to low pH recorded significantly lower amounts of Na than those with no history of acidic exposure. It therefore seems very likely that the clams may implement less costly and more ATP-efficient ion regulatory mechanisms to maintain pH homeostasis in the calcifying fluid following transgenerational acclimation. Our results suggest that marine bivalves may have a greater capacity to acclimate or adapt to ocean acidification by the end of this century than currently understood. Copyright © 2016 Elsevier B.V. All rights reserved.

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

NARCIS (Netherlands)

Cranford, P.J.; Kamermans, P.; Krause, G.H.M.; Mazurie, J.

2012-01-01

An ecosystem-based approach to bivalve aquaculture management is a strategy for the integration of aquaculture within the wider ecosystem, including human aspects, in such a way that it promotes sustainable development, equity, and resilience of ecosystems. Given the linkage between social and

Decadal climate variation recorded in modern global carbonate archives (brachiopods, molluscs)

Science.gov (United States)

Romanin, Marco; Zaki, Amir H.; Davis, Alyssa; Shaver, Kristen; Wang, Lisha; Aleksandra Bitner, Maria; Capraro, Luca; Preto, Nereo; Brand, Uwe

2017-04-01

The progress of the Earth's warming trend has rapidly accelerated in the last few decades due to the increase in emission of anthropogenic greenhouse gases. The exchange of heat between the atmosphere and seawater has consequently elevated the rate of temperature buildup in the low and high latitude ocean. Records of the variation in seawater temperature in response to local and global changes in climate are preserved within the carbonate structures of marine biogenic archives. Investigating the isotopic composition of the archives' growth increments documents the magnitude of sea surface temperature (SST) change. A long-term (1956-2012) record of temperature change in sub-tropical seawater was acquired from the giant clam Tridacna maxima collected from the Red Sea in conjunction with published results of the oyster Hyotissa hyotis (Titschack et al., 2010). Variation in polar-subpolar SST was obtained from the brachiopod Magellania venosa recovered from the coastal area of southern Chile, and from the proxy record of Hemithiris psittacea of Hudson Bay (Brand et al., 2014). The former reveals a long-term (1961-2012) time-series of Antarctic-induced oceanographic change in the southern hemisphere, while the latter represents a trend of Hudson Bay seawater SST in the northern hemisphere. Evaluation of the isotopic compositions confirms the equilibrium incorporation of oxygen isotopes with respect to ambient seawater in brachiopods and some bivalves. A general trend of decreasing δ18O values in the Red Sea molluscs is observed, indicating an increase in tropical seawater temperature of about 0.79°C since 1988. The δ18O values of the polar-subpolar brachiopods display similar depletion slopes but of larger magnitudes than that of the Red Sea archives. This signifies a rise in seawater temperature of about 1.47°C in Hudson Bay since 1991, and about 2.08°C in southern Chile since 1988. The 2013 IPCC report suggests an increase in SST of +0.094°C per decade (average

Essais de decontamination des huitres Crassostrea gigas en bassin par renouvellement et circulation de l''eau

OpenAIRE

Faury, Nicole; Masson, Daniel; Ratiskol, Jacqueline

1992-01-01

The germs decreasing of artificially contaminated oysters Crassostrea gigas has been studied in experimental tanks similar to a shellfish depuration plant, without any chemical or physical water treatment. The oyster were treated by three different water management pattern, compared to a control tank and the germs decreasing studied by MPN method of fecal Coliforms and Streptococus. As a result: 1) it appaears somewhat difficult to conclude in this first attempt about the most efficient treat...

Responses of freshwater molluscs to environmental factors in Southern Brazil wetlands Respostas de moluscos límnicos a fatores ambientais em áreas úmidas do sul do Brasil

Directory of Open Access Journals (Sweden)

L. Maltchik

2010-08-01

Full Text Available Freshwater molluscs play an important role in aquatic ecosystems, providing food for many fish species and vertebrates. Investigations on factors that determine mollusc species richness and distribution in wetland systems are scarce in the Neotropical region. The main goal of this study was to determine how much variation in mollusc richness and composition is explained by area, hydroperiod, altitude, water conductivity, and dominant aquatic vegetation. This survey was performed in an extensive area of a Neotropical region (~280,000 km² in southern Brazil, with a large number of wetland systems (111 and covering a wide gradient of altitude and wetland surface area. The mollusc richness was positively associated with wetland area and negatively associated with altitude. The richness and composition of the freshwater molluscs were similar between permanent and intermittent wetlands and it did not differ significantly between aquatic bed and emergent wetlands. The first three axes of CCA explained 16.2% of the total variation in the composition of the freshwater mollusc observed. The variation in the composition had a correlation with wetland area, altitude and water conductivity. Our results showed that the wetlands are important habitats for molluscs in southern Brazil, and that the richness and the composition of molluscs were associated with area, altitude, water conductivity and dominant vegetation.Moluscos límnicos desempenham um papel importante em ecossistemas aquáticos, fornecendo alimento para diversos peixes e vertebrados. Investigações sobre os fatores que determinam a riqueza e a distribuição das espécies de moluscos em áreas úmidas são escassos na região neotropical. O principal objetivo deste estudo foi determinar a variação na riqueza e na composição de moluscos em função da área, hidroperíodo, altitude, condutividade da água e tipo de vegetação aquática dominante. Este estudo foi desenvolvido em uma extensa

Is oxidative stress related to cadmium accumulation in the Mollusc Crassostrea angulata?

Energy Technology Data Exchange (ETDEWEB)

Macías-Mayorga, Dayanara, E-mail: dayanara.macias@uleam.edu.ec [Instituto de Ciencias Marinas de Andalucía (CSIC), Campus Río San Pedro, S/N, 11510 Puerto Real, Cádiz (Spain); Departamento Central De Investigación (DCI), Universidad Laica Eloy Alfaro de Manabí, Vía San Mateo, Manta (Ecuador); Laiz, Irene [Departamento de Física Aplicada, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Campus Río San Pedro, S/N, 11510 Puerto Real, Cádiz (Spain); Moreno-Garrido, Ignacio; Blasco, Julián [Instituto de Ciencias Marinas de Andalucía (CSIC), Campus Río San Pedro, S/N, 11510 Puerto Real, Cádiz (Spain)

2015-04-15

Highlights: • The cadmium accumulation in C. angulata tended toward a stationary state. • Metallothionein-like protein (MTLP) is clearly induced by Cd accumulation. • The MTLP detoxification mechanism is affected at high Cd concentrations. • Cadmium toxicity causes GSH levels to decrease and inhibits antioxidant enzymes. - Abstract: The kinetics of cadmium (Cd) accumulation in the gills and digestive gland of Crassotrea angulata at three concentrations of cadmium (0.088 μM, 0.44 μM and 2.22 μM) was monitored for 28 days. The relationship between accumulation and toxicity was studied using metallothionein-like protein (MTLP) concentration and reduced glutathione levels (GSH) as biochemical endpoints. The activity of enzymes which form part of the antioxidant defense system, in particular glutathione reductase (GR), total glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT), as enzymatic endpoints, was also assessed. A first order kinetic model demonstrated that the accumulation process does not take place linearly, as the Cd concentration in gills and digestive gland tended toward a stationary state. Metallothionein-like protein is clearly induced by Cd accumulation; however, at high Cd concentrations the detoxification mechanism of this protein is affected. High Cd concentrations (2.22 μM) lead to a decrease in GSH levels, and also inhibit antioxidant enzyme activities, demonstrating the adverse effect of this metal on the antioxidant balance system.

Is oxidative stress related to cadmium accumulation in the Mollusc Crassostrea angulata?

Science.gov (United States)

Macías-Mayorga, Dayanara; Laiz, Irene; Moreno-Garrido, Ignacio; Blasco, Julián

2015-04-01

The kinetics of cadmium (Cd) accumulation in the gills and digestive gland of Crassotrea angulata at three concentrations of cadmium (0.088 μM, 0.44 μM and 2.22 μM) was monitored for 28 days. The relationship between accumulation and toxicity was studied using metallothionein-like protein (MTLP) concentration and reduced glutathione levels (GSH) as biochemical endpoints. The activity of enzymes which form part of the antioxidant defense system, in particular glutathione reductase (GR), total glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT), as enzymatic endpoints, was also assessed. A first order kinetic model demonstrated that the accumulation process does not take place linearly, as the Cd concentration in gills and digestive gland tended toward a stationary state. Metallothionein-like protein is clearly induced by Cd accumulation; however, at high Cd concentrations the detoxification mechanism of this protein is affected. High Cd concentrations (2.22 μM) lead to a decrease in GSH levels, and also inhibit antioxidant enzyme activities, demonstrating the adverse effect of this metal on the antioxidant balance system. Copyright © 2015 Elsevier B.V. All rights reserved.

Is oxidative stress related to cadmium accumulation in the Mollusc Crassostrea angulata?

International Nuclear Information System (INIS)

Macías-Mayorga, Dayanara; Laiz, Irene; Moreno-Garrido, Ignacio; Blasco, Julián

2015-01-01

Highlights: • The cadmium accumulation in C. angulata tended toward a stationary state. • Metallothionein-like protein (MTLP) is clearly induced by Cd accumulation. • The MTLP detoxification mechanism is affected at high Cd concentrations. • Cadmium toxicity causes GSH levels to decrease and inhibits antioxidant enzymes. - Abstract: The kinetics of cadmium (Cd) accumulation in the gills and digestive gland of Crassotrea angulata at three concentrations of cadmium (0.088 μM, 0.44 μM and 2.22 μM) was monitored for 28 days. The relationship between accumulation and toxicity was studied using metallothionein-like protein (MTLP) concentration and reduced glutathione levels (GSH) as biochemical endpoints. The activity of enzymes which form part of the antioxidant defense system, in particular glutathione reductase (GR), total glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT), as enzymatic endpoints, was also assessed. A first order kinetic model demonstrated that the accumulation process does not take place linearly, as the Cd concentration in gills and digestive gland tended toward a stationary state. Metallothionein-like protein is clearly induced by Cd accumulation; however, at high Cd concentrations the detoxification mechanism of this protein is affected. High Cd concentrations (2.22 μM) lead to a decrease in GSH levels, and also inhibit antioxidant enzyme activities, demonstrating the adverse effect of this metal on the antioxidant balance system

Influence of the Bottom Sediment Characteristics on the Bivalve Mollusk Anadara kagoshimensis Histopathology's Variability in the Northeastern Coast of the Black Sea

Science.gov (United States)

Kolyuchkina, G. A.; Budko, D. F.; Chasovnikov, V. K.; Chzhu, V. P.

2017-11-01

With increasing anthropogenic impact on the environment, investigations of organism's response to the contamination of natural habitats, are especially relevant. In the present study, we sought to identify the correlation between the bottom sediments and local variability in histopathology of Anadara kagoshimensis (Bivalvia) in four sites of the north-eastern coast of the Black Sea. Bottom sediment grain size, redox potential of pore water, heavy metals, benzo-α-pyrene and DDT concentrations have been used as characteristics of bottom sediments. Analysis of the data revealed differences in the geochemical background of the studied sites and the histopathological state of the molluscs from these areas. Among the 10 studied elements as well as benzo-α-pyrene and DDT, only Ni has shown an exceedance of statutory limits of concentration in bottom sediments. The study reveals a relationship between Ni concentration in the bottom sediments and frequency of heavy histopathologies in the molluscs. In addition to causes directly related to pollution, mild pathology may be influenced by "natural" causes; in particular, the high content of brown cells in the connective tissue of the digestive gland may be due to the age of molluscs.

Biodepuration of polynuclear aromatic hydrocarbons from a bivalve mollusc, Mercenaria mercenaria L

International Nuclear Information System (INIS)

Tanacredl, J.T.; Cardenas, R.R.

1991-01-01

Mercenaria mercenaria, exposed in vitro for 48 h to nine parent polynuclear aromatic hydrocarbons (PAHs) found in waste crankcase oil (WCCO) and analyzed by multiparametric analysis over a 45-day depuration period in an activated carbon filtration aquaria system, did not depurate PAHs, but rather maintained them at detectable levels. Uptake of PAHs was shown to be directly related to clam weight. A cluster analysis of empirical results reaffirmed a biostabilization in PAH groupings in clam tissue over a 45-day depuration period and exhibited no evidence of a decreasing trend in total PAHs when subjected to ANOVA. Due to the commercial importance of hard-shell clams, the practices of clam depuration and clam relaying are reviewed in light of potential long-terms public health exposures to low-level xenobiotics and the implications for human consumers

Detection and quantification of Sapovirus in bivalve molluscs from Galicia (NW Spain.

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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.

Bioaccumulation of Trace Elements in Ruditapes philippinarum from China: Public Health Risk Assessment Implications

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Xiwu Yan

2013-04-01

Full Text Available The Manila clam Ruditapes philippinarum is one of the most important commercial bivalve species consumed in China. Evaluated metal burden in bivalve molluscs can pose potential risks to public health as a result of their frequent consumption. In this study, concentrations of 10 trace elements (Cu, Zn, Mn, Se, Ni, Cd, Cr, Pb, Hg and As were determined in samples of the bivalve Ruditapes philippinarum, collected from nine mariculture zones along the coast of China between November and December in 2010, in order to evaluate the status of elemental metal pollution in these areas. Also, a public health risk assessment was untaken to assess the potential risks associated with the consumption of clams. The ranges of concentrations found for Cu, Zn, Mn, Se, Ni, Cd, Cr, Pb, Hg and As in R. philippinarum were 12.1–38.0, 49.5–168.3, 42.0–68.0, 4.19–8.71, 4.76–14.32, 0.41–1.11, 0.94–4.74, 0.32–2.59, 0.03–0.23 and 0.46–11.95 mg·kg−1 dry weight, respectively. Clear spatial variations were found for Cu, Zn, Cr, Pb, Hg and As, whereas Mn, Se, Ni, and Cd did not show significant spatial variation. Hotspots of trace element contamination in R. philippinarum can be found along the coast of China, from the north to the south, especially in the Bohai and Yellow Seas. Based on a 58.1 kg individual consuming 29 g of bivalve molluscs per day, the values of the estimated daily intake (EDI of trace elements analyzed were significantly lower than the values of the accepted daily intake (ADI established by Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (JFAO/WHO and the guidelines of the reference does (RfD established by the United States Environmental Protection Agency (USEPA. Additionally, the risk of trace elements to humans through R. philippinarum consumption was also assessed. The calculated hazard quotients (HQ of all trace elements were less than 1. Consequently, there was no obvious

Phylogenetic patterns and phenotypic plasticity of molluscan sexual systems.

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Collin, Rachel

2013-10-01

Molluscs show a wide diversity of sexual systems and strategies. There are both gastropod and bivalve families that are each primarily dioecious, simultaneous hermaphrodites, or sequential hermaphrodites, and other families in which almost every sexual strategy occurs. The multiple evolutionary transitions of sexual systems within molluscs would allow comparative analyses of the associated ecological factors, but data on all but a few groups are too sparse to draw many solid conclusions. The phylogenetic distribution of sexual systems in the Mollusca shows that gastropods and bivalves demonstrate different patterns, possibly associated with the presence/absence of copulation. The distribution of change of sex suggests that, in gastropods, sequential hermaphrodites do not evolve from simultaneous hermaphrodites, and that sex reversal (flip-flopping) occurs in free-spawners but not in copulators. Three well-studied protandrous gastropod groups (calyptraeids, coralliophilids, and patellogastropods) show similar responses to environmental conditions and associations with conspecifics. They all have the following attributes: (1) they are sedentary, (2) they live in groups, patches, or aggregates, and (3) size at sex change varies among sites and among aggregates. In addition the available experimental evidence suggests that (4) the presence of females or large individuals represses growth and sex change of males, and (5) behavior seems to mediate the repressive influence of large females. Available data from other species tend to support these patterns. Finally, the repression of growth of males by females in protandry likely facilitates the evolution of dwarf males.

Co-Option and De Novo Gene Evolution Underlie Molluscan Shell Diversity

Science.gov (United States)

Aguilera, Felipe; McDougall, Carmel

2017-01-01

Abstract Molluscs fabricate shells of incredible diversity and complexity by localized secretions from the dorsal epithelium of the mantle. Although distantly related molluscs express remarkably different secreted gene products, it remains unclear if the evolution of shell structure and pattern is underpinned by the differential co-option of conserved genes or the integration of lineage-specific genes into the mantle regulatory program. To address this, we compare the mantle transcriptomes of 11 bivalves and gastropods of varying relatedness. We find that each species, including four Pinctada (pearl oyster) species that diverged within the last 20 Ma, expresses a unique mantle secretome. Lineage- or species-specific genes comprise a large proportion of each species’ mantle secretome. A majority of these secreted proteins have unique domain architectures that include repetitive, low complexity domains (RLCDs), which evolve rapidly, and have a proclivity to expand, contract and rearrange in the genome. There are also a large number of secretome genes expressed in the mantle that arose before the origin of gastropods and bivalves. Each species expresses a unique set of these more ancient genes consistent with their independent co-option into these mantle gene regulatory networks. From this analysis, we infer lineage-specific secretomes underlie shell diversity, and include both rapidly evolving RLCD-containing proteins, and the continual recruitment and loss of both ancient and recently evolved genes into the periphery of the regulatory network controlling gene expression in the mantle epithelium. PMID:28053006

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.

Element availability of bivalve with symbiotic zooxanthellae in coral sea area as studied by multielement profiling analysis

Science.gov (United States)

Itoh, A.; Kabe, N.

2008-12-01

In coral sea, a characteristic ecosystem is formed by many kinds of marine animals and plants, although seawater is uneutrophic. This may be explained by the fact that various chemical species with bioessentiality are effectively taken and used by lower animals and plants in coral sea area. A symbiotic relationship often found among different animals and plants in this area is considered to be working as one of such processes. However, the specific bioavailability of the elements for the marine animals and plants in coral reef area has not been studied from the viewpoints of trace and ultratrace elements. It is found by the present authors that bivalve with symbiotic zooxanthellae (Tridacna crocea) living on coral reef had relatively higher bio- accumulation factors for many bio-essential elements than other kinds of bivalves, although they live in the uneutrophic sea area. The present authors focused on Tridacna crocea as one of the symbiotic animals. Thus, in the present study, at first, multielement determination of major-to-ultratrace elements (about 20 elements) in each organ of Tridacna crocea with symbiotic zooxanthellae, were carried out by ICP-AES, ICP- MS, and CHN coder. At Second, the specific bioavailability of trace and ultratrace elements in Tridacna crocea was discussed on the multielement data for seawater, seaweeds, and other bivalves in coral sea area.

Viral gametocytic hypertrophy of the Pacific oyster Crassostrea gigas in Ireland.

Science.gov (United States)

Cheslett, Deborah; McKiernan, Frank; Hickey, Cathy; Collins, Evelyn

2009-02-25

Viral gametocytic hypertrophy (VGH) was detected during an investigation of mortalities in Pacific oysters Crassostrea gigas from 2 separate Irish production sites. The basophilic inclusions were observed in the gonad tissue of oysters sampled in August and October 2007. The oysters involved did not show any macroscopic disease signs. Transmission electron microscopy demonstrated the presence of viral particles in these intranuclear inclusions. The particles were small, non-enveloped, icosahedral and approximately 50 nm in diameter, and thus had characteristics similar to the Papillomaviridae and Polyomaviridae families. No host defence reaction was observed. The viral particles described here appear to be similar to those described in C. virginica from the USA and Canada and to those described in C. gigas from Korea and France.

Elemental composition of Chesapeake Bay oyster Crassostrea virginica in the vicinity of Calvert Cliffs Nuclear Power Plant

International Nuclear Information System (INIS)

Gavrilas, M.; Munno, F.J.

1984-01-01

The stable element composition of the American oyster Crassostrea virginica collected between June 1978 and August 1983 in the Chesapeake Bay in the vicinity of Calvert Cliffs Nuclear Power Plant was analyzed by neutron activation. The minimum, maximum and the mean values of the elemental concentrations are given. The seasonal effect and the linear correlation between elements entering the oyster composition are shown. 7 references, 1 figure, 4 tables

Vibrios patogênicos em ostras (Crassostrea rhizophorae servidas em restaurantes no Rio de Janeiro: um alerta para a Saúde Pública Pathogenic Vibrios in oysters (Crassostrea rhizophorae served at restaurants in Rio de Janeiro: a public health warning

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Christiane Soares Pereira

2007-06-01

Full Text Available Avaliaram-se 40 amostras de ostras (Crassostrea rhizophorae servidas in natura em 15 restaurantes da Cidade do Rio de Janeiro, a fim de investigar a presença de Vibrio spp. As amostras de ostras foram analisadas e submetidas a enriquecimento em água peptonada alcalina adicionada de 1 e 3% de NaCl, incubadas a 37°C por 24 horas. Em seguida, os cultivos foram semeados em agar tiossulfato citrato bile sacarose e as colônias suspeitas foram submetidas à caracterização bioquímica. Vibrio parahaemolyticus, Vibrio carchariae, Vibrio alginolyticus e Vibrio vulnificus representaram as principais espécies (> 60% isoladas a partir das ostras in natura.Forty oyster samples (Crassostrea rhizophorae served raw in 15 restaurants in the city of Rio de Janeiro were evaluated in order to investigate the presence of Vibrio spp. The oyster samples were analyzed and subjected to enrichment in alkaline peptone water with the addition of 1 and 3% NaCl and incubated at 37°C for 24 hours. Following this, the cultures were seeded onto thiosulfate citrate bile sucrose agar (TCBS and the suspected colonies were subjected to biochemical characterization. Vibrio parahaemolyticus, Vibrio carchariae, Vibrio alginolyticus and Vibrio vulnificus were the main species (> 60% isolated from raw oysters.

Shell biofilm-associated nitrous oxide production in marine molluscs: processes, precursors and relative importance.

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Heisterkamp, Ines M; Schramm, Andreas; Larsen, Lone H; Svenningsen, Nanna B; Lavik, Gaute; de Beer, Dirk; Stief, Peter

2013-07-01

Emission of the greenhouse gas nitrous oxide (N2 O) from freshwater and terrestrial invertebrates has exclusively been ascribed to N2 O production by ingested denitrifying bacteria in the anoxic gut of the animals. Our study of marine molluscs now shows that also microbial biofilms on shell surfaces are important sites of N2 O production. The shell biofilms of Mytilus edulis, Littorina littorea and Hinia reticulata contributed 18-94% to the total animal-associated N2 O emission. Nitrification and denitrification were equally important sources of N2 O in shell biofilms as revealed by (15) N-stable isotope experiments with dissected shells. Microsensor measurements confirmed that both nitrification and denitrification can occur in shell biofilms due to a heterogeneous oxygen distribution. Accordingly, ammonium, nitrite and nitrate were important drivers of N2 O production in the shell biofilm of the three mollusc species. Ammonium excretion by the animals was found to be sufficient to sustain N2 O production in the shell biofilm. Apparently, the animals provide a nutrient-enriched microenvironment that stimulates growth and N2 O production of the shell biofilm. This animal-induced stimulation was demonstrated in a long-term microcosm experiment with the snail H. reticulata, where shell biofilms exhibited the highest N2 O emission rates when the animal was still living inside the shell. © 2012 John Wiley & Sons Ltd and Society for Applied Microbiology.

Abundance, biomass and caloric content of Chukchi Sea bivalves and association with Pacific walrus (Odobenus rosmarus divergens) relative density and distribution in the northeastern Chukchi Sea

Science.gov (United States)

Young, Jordann K.; Black, Bryan A.; Clarke, Janet T.; Schonberg, Susan V.; Dunton, Kenneth H.

2017-10-01

The northeastern Chukchi Sea is a shallow subarctic shelf ecosystem that supports a substantial benthic infaunal community of which bivalves are a major component. We assessed the patterns in population abundance, biomass, and caloric content of ten dominant bivalve taxa in relation to the distribution of the upper trophic level consumer Pacific walrus (Odobenus rosmarus divergens). Bivalves were collected over four cruises in the northeastern Chukchi Sea (2009, 2010, 2012, 2013). Our samples were largely dominated by calorie-dense, deposit-feeding species, including Macoma spp., Ennucula tenuis, Nuculana spp. and Yoldia spp. Weight-frequency distributions were strongly right-skewed for most taxa, though some showed evidence of a bimodal distribution. Caloric densities as measured through bomb calorimetry significantly differed among taxa (ANOVA F = 32.57, df = 9, p-valueanimal wet weight was found to be a reliable predictor of whole animal caloric content. Bivalve populations and peak caloric densities were centered on and to the southeast of Hanna Shoal, which coincided with peak Pacific walrus relative density (walruses per km surveyed) from July through October. Significant differences in mean caloric values were found between areas with and without walruses present (student's t-test, t=-2.9088, df = 252.24, p-value = 0.003952), as well as between areas with low and high walrus relative densities in the pooled annual dataset and in each individual month except October (ANOVA, p-value<0.05). The high-calorie deposit feeders that dominate these bivalve communities preferentially consume food sources, such as sea ice algae, that are likely to be affected by shifting sea ice dynamics. As such, continued warming has the potential to alter bivalve communities in the northeastern Chukchi Sea, which may have profound implications for upper trophic levels.

Isolation of vibrio spp. In oysters (crassostrea rhizophorea) caught in the ‘de la virgen’ swamp

OpenAIRE

López Gutiérrez, Lercy; Autor; Manjarrez Pava, Ganiveth; Autor; Herrera Rodríguez, Lilibeth; Autor; Montes Payares, Ana Elena; Autor; Olascuaga Ruíz, Yuranis Paola; Autor; Ortega Quiroz, Rolando José; Autor

2015-01-01

Objective:  To establish contamination by Vibrio in oysters (Crassostrea rhizophorae) caught in De La Virgen Swamp, in order to alert entities in charge or protecting consumer health in Cartagena city. Methods: Between February and April 2006, 67 oysters from 5 strategic sites along De La Virgen Swamp, were analyzed. Insulation and identification of Vibrio was performed through a culture and biochemical tests.Results.  Predominant species were V. alginolyticus (23%),V fluvialis  (20%),V. para...

Effects of cadmium on anaerobic energy metabolism and mRNA expression during air exposure and recovery of an intertidal mollusk Crassostrea virginica

International Nuclear Information System (INIS)

Ivanina, Anna V.; Sokolov, Eugene P.; Sokolova, Inna M.

2010-01-01

Marine organisms are exposed to periodical oxygen deficiency and pollution stress in estuarine and coastal zones which may strongly affect their performance and survival. We studied the combined effects of exposure to a common pollutant, cadmium (Cd), and intermittent anoxia on anaerobic metabolism, energy status and mRNA expression of 13 genes involved in and/or controlled by the hypoxia inducible factor-1 (HIF-1) pathway in hepatopancreas of an intertidal bivalve, the eastern oyster Crassostrea virginica. In control oysters, prolonged anoxia resulted in a selective suppression of nitric oxide synthase (NOS) and upregulation of cytochrome c oxidase subunit IV (COX4) while the levels of other transcripts remained unchanged. During post-anoxic recovery, mRNA expression of hypoxia inducible factor-1α (HIF-1α) was elevated, phosphoenolpyruvate carboxykinase (PEPCK), NOS and LON protease suppressed, and mRNA expression of other studied genes not changed. Notably, most of the key glycolytic genes that are stimulated by HIF-1 in mammals, either remained unchanged or were downregulated in anoxic oysters suggesting a different mechanism of molecular response to oxygen deficiency. Patterns of transcriptional response during anoxia and reoxygenation were significantly altered by Cd exposure in a gene-specific manner. Anaerobic metabolism (indicated by accumulation of L-alanine, succinate and acetate during anoxia) was also suppressed in Cd-exposed oysters. In control oysters, ATP turnover rate (M ATP ) during anoxia was mostly sustained by anaerobic glycolysis with negligible contributions from ATP and PLA breakdown. In contrast, in Cd-exposed oysters ATP breakdown contributed significantly to anaerobic M ATP . Thus, while control oysters could efficiently defend the ATP levels and tissue energy status during prolonged anoxia, Cd-exposed oysters experienced a disturbance in tissue energy balance indicated by the depletion of ATP, a rapid decline in adenylate energy charge

Effects of cadmium on anaerobic energy metabolism and mRNA expression during air exposure and recovery of an intertidal mollusk Crassostrea virginica

Energy Technology Data Exchange (ETDEWEB)

Ivanina, Anna V. [Biology Department, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223 (United States); Sokolov, Eugene P. [Department of General Surgery, Carolina' s Medical Center, 1000 Blythe Blvd., Charlotte, NC 28203-5871 (United States); Sokolova, Inna M., E-mail: isokolov@uncc.edu [Biology Department, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223 (United States)

2010-09-01

Marine organisms are exposed to periodical oxygen deficiency and pollution stress in estuarine and coastal zones which may strongly affect their performance and survival. We studied the combined effects of exposure to a common pollutant, cadmium (Cd), and intermittent anoxia on anaerobic metabolism, energy status and mRNA expression of 13 genes involved in and/or controlled by the hypoxia inducible factor-1 (HIF-1) pathway in hepatopancreas of an intertidal bivalve, the eastern oyster Crassostrea virginica. In control oysters, prolonged anoxia resulted in a selective suppression of nitric oxide synthase (NOS) and upregulation of cytochrome c oxidase subunit IV (COX4) while the levels of other transcripts remained unchanged. During post-anoxic recovery, mRNA expression of hypoxia inducible factor-1{alpha} (HIF-1{alpha}) was elevated, phosphoenolpyruvate carboxykinase (PEPCK), NOS and LON protease suppressed, and mRNA expression of other studied genes not changed. Notably, most of the key glycolytic genes that are stimulated by HIF-1 in mammals, either remained unchanged or were downregulated in anoxic oysters suggesting a different mechanism of molecular response to oxygen deficiency. Patterns of transcriptional response during anoxia and reoxygenation were significantly altered by Cd exposure in a gene-specific manner. Anaerobic metabolism (indicated by accumulation of L-alanine, succinate and acetate during anoxia) was also suppressed in Cd-exposed oysters. In control oysters, ATP turnover rate (M{sub ATP}) during anoxia was mostly sustained by anaerobic glycolysis with negligible contributions from ATP and PLA breakdown. In contrast, in Cd-exposed oysters ATP breakdown contributed significantly to anaerobic M{sub ATP}. Thus, while control oysters could efficiently defend the ATP levels and tissue energy status during prolonged anoxia, Cd-exposed oysters experienced a disturbance in tissue energy balance indicated by the depletion of ATP, a rapid decline in

Utilization of detrital complexes by the oyster, Crassostrea virginica (Gmelin)

International Nuclear Information System (INIS)

Crosby, M.P.

1987-01-01

The contribution of bacteria and nonliving particulate organic matter of detrital complexes to the nutrition of the American oyster, Crassostrea virginica, was investigated in the laboratory under normal feeding conditions. Results indicate the oysters were capable of assimilating crude fiber extracted from 14 C-Spartina alterniflora with an efficiency of approximately 3% and that enteric bacteria did not enhance this process. Less than 1% of an oyster's energetic demands could be met by direct utilization of this substrate, in the Choptank River subestuary of the Chesapeake Bay. The potential contribution of refractory organics to oysters in large salt marshes having crude fiber concentration greater than in the Choptank system, are discussed. The ability of the oyster to utilize 14 C and 15 N from cellulolytic marine bacteria, isolated from a S. alterniflora dominated salt marsh, was also studied

Efeitos do caranguejo Pinnotheres ostreum em ostras Crassostrea rhizophorae

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Iracema Andrade Nascimento

1980-12-01

Full Text Available Some biological parameters of the oyster (Crassostrea rhizopharae, during the spawning and post-spawning periods, were analised in relation to the infestation by the pea crab (Pinnotheres ostreum The biological parameters considered were: size, total weight, wet and dry meat weight, and condition index. Utilizing the χ2 test these parameters and infestation by the pea crab were shown to to be associated. The incidence of pea crabs was higher during the spawning period than in the post-spawning period, reaching a maximum (20.3% infestation in oysters with a size of 6 to 7 cm. The values of the condition index and percent of meat (wet and dry weight for these oysters were significantly (P < 0.05 lower than for uninfested oysters. From these results there seems to be no doubt that the pea crab (V. ostreum injures the mangrove oysters which supports the conclusion that these crabs are true parasites for C. rhizophorae.

Light and scanning electron microscopic studies of Unionicola tetrafurcatus (Acari: Unionicolidae) infecting four freshwater bivalve species with referring to histopathological effect on its hosts.

Science.gov (United States)

Abdel-Gaber, Rewaida; Fol, Mona; Al Quraishy, Saleh

2018-05-08

Water mites of the genus Unionicola are the most common symbionts of freshwater bivalves. During the current investigation, a total of 120 live freshwater mussels [Corbicula fluminea (Veneroida), Coelatura aegyptiaca (Unionoidea) Mutela rostrata and Chambardia rubens (Mutelidae)], were collected from 2 localities in Tura (Helwan Governorate) and El Kanater (Qaluobiya Governorate), Egypt. Only 3 of the 4 bivalve species listed are considered freshwater bivalves (members of Unionoidea). While, C. fluminea belong to the family Cyrenidae within Veneroida. The collected mussels were dissected and examined for the presence of unionicolid mites. It was found that 30.83% (37/120) were infected with a single mite species Unionicola tetrafurcatus (Unionicolidae). The highest prevalence was observed during the summer with 83.33% (25/30), whereas the least was observed in autumn, i.e. 33.33% (10/30). Mites were recovered from the gills, gonads, and visceral mass of mussel hosts. gills of host mussels were the primary site of oviposition for unionicola mites. Smaller bivalves in size had significantly greater numbers of mites than larger ones in size. Numbers of mites per host species was variable and the highest prevalence level of 83.33% (25/30) was recorded in C. fluminea, while, the lowest one of 16.66% (5/30) was found in C. rubens. Morphological and morphometric characterizations of mites revealed some differences between the present species and other related Unionicola. Histopathological responses of host mussels to the eggs, larvae, and cuticular remnants of U. tetrafurcatus were also studied. Therefore, the present study demonstrated that freshwater bivalves have a new host and locality records for infection with U. tetrafurcatus. Future studies are recommended to include advanced molecular characteristics for these mites.

Les phénoloxydases chez l’huître creuse Crassostrea gigas : biomarqueurs potentiels de stress environnemental

OpenAIRE

Luna Acosta , Andrea

2010-01-01

The Pacific oyster Crassostrea gigas is the leading aquaculture product at the worldwide level. However, massive summer mortalities affect dramatically cultivated and natural oyster populations, especially at young life stages. These events could be linked to an unbalance between the different actors of the triad host – pathogen agent – environment, which could favour a weakening of defence mechanisms in the host, and consequently, the emergence and/or increase of diseases. Among environmenta...

Effects of storage on microbial loads of two commercially important shellfish species, Crassostrea virginica and Mercenaria campechiensis.

OpenAIRE

Hood, M A; Ness, G E; Rodrick, G E; Blake, N J

1983-01-01

The effects of storage on the microbial load in two commercially important species of shellfish were examined. Oysters (Crassostrea virginica) were stored as shellstock, shucked meats, and fully processed meats at four temperatures for up to 21 days, and clams (Mercenaria campechiensis) were stored only as shellstock. The concentrations of most microbiological groups of organisms increased with the duration and temperature of storage in both shellfish species, although the increases were sign...

Induction of gynogenetic haploidy in oyster Crassostrea gigas, using ultra violet irradiated sperms

Energy Technology Data Exchange (ETDEWEB)

Goswami, Usha [National Inst. of Oceanography, Panaji (India)

1993-06-01

Eggs of Crassostrea gigas were fertilized with sperms exposed to different doses of UV irradiations by keeping a constant rate of 121.47 ergs.mm[sup -2]sec[sup -1] and changing the period of exposure from 4 to 90 sec. Samples of larvae were analysed for chromosomal ploidy, rate of fertilization, developmental and chromosomal abnormalities. The gynogenetic haploid larvae first made their appearance in the 30 and 50 sec group exposed to 3644 and 6074 ergs mm[sup -2] UV. The maximum number was found in the 90 sec group exposed to 10932 ergs mm[sup -2] UV. (author). 11 refs., 1 tab., 1 fig.

HMGB in mollusk Crassostrea ariakensis Gould: structure, pro-inflammatory cytokine function characterization and anti-infection role of its antibody.

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Ting Xu

Full Text Available BACKGROUND: Crassostrea ariakensis Gould is a representative bivalve species and an economically important oyster in China, but suffers severe mortalities in recent years that are caused by rickettsia-like organism (RLO. Prevention and control of this disease is a priority for the development of oyster aquaculture. It has been proven that mammalian HMGB (high mobility group box can be released extracellularly and acts as an important pro-inflammatory cytokine and late mediator of inflammatory reactions. In vertebrates, HMGB's antibody (anti-HMGB has been shown to confer significant protection against certain local and systemic inflammatory diseases. Therefore, we investigated the functions of Ca-HMGB (oyster HMGB and anti-CaHMGB (Ca-HMGB's antibody in oyster RLO/LPS (RLO or LPS-induced disease or inflammation. METHODOLOGY/PRINCIPAL FINDINGS: Sequencing analysis revealed Ca-HMGB shares conserved structures with mammalians. Tissue-specific expression indicates that Ca-HMGB has higher relative expression in hemocytes. Significant continuous up-regulation of Ca-HMGB was detected when the hemocytes were stimulated with RLO/LPS. Recombinant Ca-HMGB protein significantly up-regulated the expression levels of some cytokines. Indirect immunofluorescence study revealed that Ca-HMGB localized both in the hemocyte nucleus and cytoplasm before RLO challenge, but mainly in the cytoplasm 12 h after challenge. Western blot analysis demonstrated Ca-HMGB was released extracellularly 4-12 h after RLO challenge. Anti-CaHMGB was added to the RLO/LPS-challenged hemocyte monolayer and real-time RT-PCR showed that administration of anti-CaHMGB dramatically reduced the rate of RLO/LPS-induced up-regulation of LITAF at 4-12 h after treatment. Flow cytometry analysis indicated that administration of anti-CaHMGB reduced RLO/LPS-induced hemocyte apoptosis and necrosis rates. CONCLUSIONS/SIGNIFICANCE: Ca-HMGB can be released extracellularly and its subcellular localization

Comparative susceptibility of veliger larvae of four bivalve mollusks to a Vibrio alginolyticus strain.

Science.gov (United States)

Luna-González, A; Maeda-Martínez, A N; Sainz, J C; Ascencio-Valle, F

2002-06-03

The susceptibility of 7 d old veliger larvae of the scallops Argopecten ventricosus and Nodipecten subnodosus, the penshell Atrina maura, and the Pacific oyster Crassostrea gigas to a pathogenic strain of Vibrio alginolyticus was investigated by challenging the larvae with different bacterial concentrations in a semi-static assay. The results indicate that the larvae of the 2 scallop species are more susceptible to the V. alginolyticus strain than those of the oyster and the penshell. Signs of the disease were similar to bacillary necrosis described in previous work. Interspecies differences in susceptibility to pathogens are discussed.

A Prince's tribute...and trial. Monaco's Prince Albert II followed the footsteps of his great great grandfather when he ventured the Arctic Archipelago to trace climate change, this time with IAEA Marine scientists

International Nuclear Information System (INIS)

Lodding, L.

2006-01-01

Monaco's Prince Albert II followed the footsteps of his great great grandfather when he ventured to the Arctic Archipelago to track climate change, this time with IAEA Marine scientists. He undertook this trip to draw global attention to the environmental damage to the Arctic regions caused by global warming. Although far away from industrialized areas, Svalbard Island is eminently suitable to observe the evolution of climate change and long-range pollutants transported from northern European countries by water currents and from North America by winds. Using nuclear techniques, it is hoped that some of the causes of climate change can be unlocked. The first of these studies was undertaken to evaluate the shell laminations of a very long-lived marine bivalve mollusc, the Ocean Quahog. The mollusc, with a life expectancy well over a century, acts as a recording of temperature variations and water chemistry. The second project aimed at determining levels of contaminates in marine zooplankton in remote arctic environments for comparison with other climatic regions

Standard Guide for Irradiation of Finfish and Aquatic Invertebrates Used as Food to Control Pathogens and Spoilage Microorganisms

CERN Document Server

American Society for Testing and Materials. Philadelphia

2009-01-01

1.1 This guide outlines procedures and operations for the irradiation of raw, untreated, fresh (chilled), or frozen finfish and aquatic invertebrates, while ensuring that the irradiated product is safe and wholesome. 1.1.1 Aquatic invertebrates include molluscs, crustacea, echinoderms, etc. 1.1.1.1 Molluscs include bivalve shellfish, such as clams, mussels, and oysters; snails; and cephalopods, such as squid and octopus. 1.1.1.2 Crustacea include shellfish such as shrimp, lobster, crabs, prawns and crayfish. 1.1.1.3 Echinoderms include sea urchins and sea cucumbers. 1.2 This guide covers absorbed doses used to reduce the microbial and parasite populations in aquatic invertebrates and finfish. Such doses typically are below 10 kGy (1). 1.3 The use of reduced-oxygen packaging (vacuum or modified atmosphere, and including products packed in oil) with irradiated, raw product is not covered by this guide. The anaerobic environment created by reduced-oxygen packaging provides the potential for outgrowth o...

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

Study of the U and Th series in Crassostrea mangle shell

Energy Technology Data Exchange (ETDEWEB)

Farias, Wellington M.; Damatto, Sandra R.; Silva, Paulo S.C., E-mail: wellington.m@usp.br, E-mail: damatto@ipen.br, E-mail: pscsilva@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Simone, Luiz R.L.; Amaral, Vanessa S., E-mail: lrsimone@usp.br, E-mail: vanessamolusco@gmail.com [Universidade de Sao Paulo (MZ/USP), Sao Paulo, SP (Brazil). Museu de Zoologia

2015-07-01

Foraminifera, corals and mollusks shells have been used as proxies for environmental, paleoenvironmental and climatic change studies in marine system by using elemental and isotopic ratios as recorder of such events. Nevertheless, there is little information available on the U and Th radionuclides decay series applied on those fields. In this sense, the objective of this paper was to evaluate the activity concentrations of the U and Th nuclide decay series in Crassostrea mangle shell samples as a function of the geographic location. Samples from Sao Paulo, Parana, Alagoas, Rio Grande do Norte and Pernambuco states were analyzed by Neutron Activation Analysis and Gross Alpha and Beta Counting. Statistical analysis applied to the obtained results allowed differencing samples coming from Sao Paulo from that coming from Parana. (author)

Study of the U and Th series in Crassostrea mangle shell

International Nuclear Information System (INIS)

Farias, Wellington M.; Damatto, Sandra R.; Silva, Paulo S.C.; Simone, Luiz R.L.; Amaral, Vanessa S.

2015-01-01

Foraminifera, corals and mollusks shells have been used as proxies for environmental, paleoenvironmental and climatic change studies in marine system by using elemental and isotopic ratios as recorder of such events. Nevertheless, there is little information available on the U and Th radionuclides decay series applied on those fields. In this sense, the objective of this paper was to evaluate the activity concentrations of the U and Th nuclide decay series in Crassostrea mangle shell samples as a function of the geographic location. Samples from Sao Paulo, Parana, Alagoas, Rio Grande do Norte and Pernambuco states were analyzed by Neutron Activation Analysis and Gross Alpha and Beta Counting. Statistical analysis applied to the obtained results allowed differencing samples coming from Sao Paulo from that coming from Parana. (author)

Mobile Element Evolution Playing Jigsaw - SINEs in Gastropod and Bivalve Mollusks.

Science.gov (United States)

Matetovici, Irina; Sajgo, Szilard; Ianc, Bianca; Ochis, Cornelia; Bulzu, Paul; Popescu, Octavian; Damert, Annette

2016-01-06

SINEs (Short INterspersed Elements) are widely distributed among eukaryotes. Some SINE families are organized in superfamilies characterized by a shared central domain. These central domains are conserved across species, classes, and even phyla. Here we report the identification of two novel such superfamilies in the genomes of gastropod and bivalve mollusks. The central conserved domain of the first superfamily is present in SINEs in Caenogastropoda and Vetigastropoda as well as in all four subclasses of Bivalvia. We designated the domain MESC (Romanian for MElc-snail and SCoica-mussel) because it appears to be restricted to snails and mussels. The second superfamily is restricted to Caenogastropoda. Its central conserved domain-Snail-is related to the Nin-DC domain. Furthermore, we provide evidence that a 40-bp subdomain of the SINE V-domain is conserved in SINEs in mollusks and arthropods. It is predicted to form a stable stem-loop structure that is preserved in the context of the overall SINE RNA secondary structure in invertebrates. Our analysis also recovered short retrotransposons with a Long INterspersed Element (LINE)-derived 5' end. These share the body and/or the tail with transfer RNA (tRNA)-derived SINEs within and across species. Finally, we identified CORE SINEs in gastropods and bivalves-extending the distribution range of this superfamily. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Aeromonas spp. isolated from oysters (Crassostrea rhizophorea from a natural oyster bed, Ceará, Brazil Aeromonas spp. isoladas de ostras (Crassostrea rhizophorea coletadas em um criadouro natural, Ceará, Brazil

Directory of Open Access Journals (Sweden)

Norma S. Evangelista-Barreto

2006-06-01

Full Text Available Between April and October 2002, thirty fortnightly collections of oysters (Crassostrea rhizophorea from a natural oyster bed at the Cocó River estuary in the Sabiaguaba region (Fortaleza, Ceará, Brazil were carried out, aiming to isolate Aeromonas spp. strains. Oyster samples were submitted to the direct plating (DP and the presence/absence (P/A methods. Aeromonas were identified in 15 (50% samples analyzed by the DP method and in 13 (43% analyzed by the P/A method. A. caviae, A. eucrenophila, A. media, A. sobria, A. trota, A. veronii bv. sobria, A. veronii bv. veronii and Aeromonas sp. were isolated. The predominant species was A. veronii (both biovars, which was identified in 13 (43% samples, followed by A. media in 11 (37% and A. caviae in seven (23%. From the 59 strains identified, 28 (48% presented resistance to at least one of the eight antibiotics tested.Foram realizadas 30 coletas quinzenais, entre abril e outubro de 2002, de ostras (Crassostrea rhizophorea de um criadouro natural, no estuário do rio Cocó (Fortaleza/Ceará/Brasil, objetivando-se isolar cepas de Aeromonas spp. As amostras de ostras foram submetidas aos métodos de plaqueamento direto (PD e presença/ausência (P/A. Foram identificadas Aeromonas em 15 (50% amostras analisadas pelo método PD e em 13 (43% pelo método P/A. Foram isoladas: A. caviae, A. eucrenophila, A. media, A. sobria, A. trota, A. veronii bv. sobria, A. veronii bv. veronii e Aeromonas sp. A espécie predominate foi A. veronii (ambos biovars, identificada em 13 (43% amostras, seguida de A. media em 11 (37% e A. caviae em 7 (23%. Das 59 cepas identificadas, 28 (48% apresentaram resistência a pelo menos um, dos oitos antibióticos testados.

Impoverishment of recent floodplain forest mollusc fauna in the lower Ohře River (Czech Republic) as a result of prehistoric human impact

Czech Academy of Sciences Publication Activity Database

Juřičková, L.; Horáčková, J.; Ložek, Vojen; Horsák, M.

2013-01-01

Roč. 42, 1 MAR (2013), s. 932-946 ISSN 0300-9483 Institutional support: RVO:67985831 Keywords : floodplain * mollusc * Ohře River (Czech Republic) Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.383, year: 2013

Managing marine mollusc diseases in the context of regional and international commerce: policy issues and emerging concerns

Science.gov (United States)

Carnegie, Ryan B.; Arzul, Isabelle; Bushek, David

2016-01-01

Marine mollusc production contributes to food and economic security worldwide and provides valuable ecological services, yet diseases threaten these industries and wild populations. Although the infrastructure for mollusc aquaculture health management is well characterized, its foundations are not without flaws. Use of notifiable pathogen lists can leave blind spots with regard to detection of unlisted and emerging pathogens. Increased reliance on molecular tools has come without similar attention to diagnostic validation, raising questions about assay performance, and has been accompanied by a reduced emphasis on microscopic diagnostic expertise that could weaken pathogen detection capabilities. Persistent questions concerning pathogen biology and ecology promote regulatory paralysis that impedes trade and which could weaken biosecurity by driving commerce to surreptitious channels. Solutions that might be pursued to improve shellfish aquaculture health management include the establishment of more broad-based surveillance programmes, wider training and use of general methods like histopathology to ensure alertness to emerging diseases, an increased focus on assay assessment and validation as fundamental to assay development, investment in basic research, and application of risk analyses to improve regulation. A continual sharpening of diagnostic tools and approaches and deepening of scientific knowledge is necessary to manage diseases and promote sustainable molluscan shellfish industries. PMID:26880834

Bacteria of fecal origin in mangrove oysters (Crassostrea rhizophorae) in the Cocó River estuary, Ceará State, Brazil

OpenAIRE

Silva,Ana I.M.; Vieira,Regine H.S.F.; Menezes,Francisca G.R.; Fonteles-Filho,Antonio A.; Torres,Regina C.O.; Sant'Anna,Ernani S.

2004-01-01

This study was aimed at evaluating the microbiological quality of mangrove oysters (Crassostrea rhizophorae), collected at a natural oyster bed in the estuary of Cocó river (Fortaleza, Ceará, Brazil). MPN values were used for estimating the total (TC) and fecal (FC) coliforms and Enterococcus spp. TC and FC MPN values in the whole muscle and intervalve liquid ranged from 1,600/g and from

Ostreid herpesvirus OsHV-1 μVar in Pacific oysters Crassostrea gigas (Thunberg 1793) of the Wadden Sea, a UNESCO world heritage site

NARCIS (Netherlands)

Gittenberger, A.; Voorbergen-Laarman, M.A.; Engelsma, M.Y.

2016-01-01

The Wadden Sea is an extensive wetland area, recognized as UNESCO world heritage site of international importance. Since the mid-1990s, the invasive Pacific oyster Crassostrea gigas (Thunberg 1793) population in the area has grown exponentially, having a distinct impact on the ecosystem. The

Evaluating the performance of selective-bred lines of eastern oysters, Crassostrea virginica, at different locations along the east coast of the United States

Science.gov (United States)

Populations of the economically important eastern oyster, Crassostrea virginica have been severely affected in the last few decades by diseases such as Dermo, MSX, SSO, and ROD. As the demand for a fast-growing, disease-resistant oyster increases, so has the need for effective breeding programs that...

Boreholes on three bivalve species found on the sand beach at Sagot Cape, Baengnyeongdo, Korea

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Dal-Yong Kong

2017-12-01

Full Text Available Circular to subcircular boreholes were found on the surfaces of three different bivalve shells (Mactra chinensis, Felaniella usta, and Nuttallia japonica that were pushed onto the sand beach at Sagot Cape, Baengnyeongdo, Korea. The boreholes are characterized by beveled holes that are parabolic in cross section. The boreholes are classified into the ichnospecies Oichnus paraboloides, probably drilled by a naticid gastropod Glossaulax didyma didyma living in the Baengnyeong tidal flat. In the case of Mactrashells, boreholes are observed more or less evenly on left and right valves, and 96% of boreholes are located on the umbo. This may suggest that the life position of the Baengnyeong bivalves did not dictate the preference of G. didyma didyma in the Baengnyeong tidal flat ecosystem. The clustered distribution of the boreholes in the umbo area indicates a strong site selectivity for boreholes that is quite a common phenomenon in many naticid gastropods. Keywords: Baengnyeongdo, Mactra chinensis, Naticid gastropods, Oichnus paraboloides, Prey–predator interactions

Levantamento de estoques da ostra Crassostrea sp. em bancos naturais no litoral paranaense

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Euler Batista Erse

2011-09-01

Full Text Available http://dx.doi.org/10.5007/2175-7925.2008v21n2p57 A importância econômica de diversas espécies de ostras nativas, em especial a Crassostrea sp., torna atrativa a exploração desta espécie pelas comunidades litorâneas. A explotação deste recurso natural, baseada somente no extrativismo não sustentável acaba por ameaçar os estoques naturais com a sobrepesca. Baseado neste fato, uma avaliação das condições dos estoques naturais desse animal torna-se importante para futuros projetos de conservação e manejo sustentáveis do recurso. Neste trabalho foram levantados dados referentes aos estoques da ostra Crassostrea sp. de três bancos naturais distintos, sendo estes, um na Ilha da Cotinga, na foz do Rio Maciel e outro na foz do Rio Biguaçú. Em cada banco, foram feitas três amostragens aleatórias durante a maré baixa sizígia utilizando-se de um quadrado de amostragem com dimensão de 30x30 cm. Observamos também neste trabalho que, dos locais de estoques naturais da ostra nativa Cras- sostrea sp. presentes na Baía de Paranaguá, o da Ilha da Cotinga apresenta signifi cativamente os maiores valores quanto ao tamanho se comparados com a o Rio Maciel e o Rio Biguaçú, sendo que, entre os dois últimos, o primeiro apresentou maiores valores. Porém, não houve diferenças signifi cativas nos valores biométricos encontrados entre os bancos amostrados nos respectivos bosques.

High pressure treatment changes spoilage characteristics and shelf life of Pacific oysters ( Crassostrea gigas) during refrigerated storage

Science.gov (United States)

Cao, Rong; Zhao, Ling; Liu, Qi

2017-04-01

The effects of high pressure (HP) treatment on spoilage characteristic and shelf life extension of Pacific oysters ( Crassostrea gigas) during refrigerated storage were studied. Results showed that HP treatment of 275 MPa for 3 min or 300 MPa for 2 min could achieve 100% full release of oyster adductor muscle, pressures higher than 350 MPa caused excessive release as the shells of oysters were broken, thus use of higher pressures should be cautious in oyster processing industry because of its adverse impact on the appearance of shells. HP treatment (300 MPa, 2 min) was proper for the shucking of Pacific oyster ( Crassostrea gigas) in China. This treatment caused no organoleptic disadvantage. Moreover, HP treatment resulted in obvious differences in biochemical spoilage indicators (pH, TVB-N and TBARS) changes and volatile compounds profile determined by electronic nose during storage. HP treatment (300 MPa, 2 min) also led to a reduction of aerobic bacterial count (APC) by 1.27 log cycles. Furthermore, the APC values of oysters treated by HP were always lower than those of the control samples during storage. Based on the organoleptic, biochemical and microbiological indicators, shelf life of 6-8 d for control and 12 d for HP-treated oysters could be expected. HP treatment showed great potential in oyster processing and preservation.

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

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...... were low, but not always lower than expected impacted areas. The most contaminated areas were harbours, where especially Copenhagen, St Croix and Sydney, can be considered hotspots of tributyltin as well as a number of metals....

Some effects of temperature and starvation on the bivalve @iDonax vittatus@@ (da Costa) in experimental laboratory populations

Digital Repository Service at National Institute of Oceanography (India)

Ansell, A.D.; Sivadas, P.

The effect of temperature on the body weight and composition, and on respiration, filtration and NH, excretion of the bivalve Donax uittatus (da Costa) has been investigated in laboratory-maintained populations under conditions of starvation In all...

Molluscan assemblages of seagrass-covered and bare intertidal flats on the Banc d'Arguin, Mauritania, in relation to characteristics of sediment and organic matter

Science.gov (United States)

Honkoop, Pieter J. C.; Berghuis, Eilke M.; Holthuijsen, Sander; Lavaleye, Marc S. S.; Piersma, Theunis

2008-11-01

The Banc d'Arguin, a non-estuarine area of shallows and intertidal flats off the tropical Saharan coast of Mauritania, is characterised by extensive intertidal and subtidal seagrass beds. We examined the characteristics of intertidal seagrass ( Zostera noltii) meadows and bare areas in terms of the presence and abundance of molluscs (gastropods and bivalves). To explain observed differences between molluscan assemblages in seagrass and bare patches, some aspects of the feeding habitat (top-5 mm of the sediment) and of food (organic materials) of molluscs were examined. The novelty of this study is that phytopigments were measured and identified to assess source and level of decay (freshness) of organic material in the sediment and to study their importance as an explanatory variable for the distribution of molluscs. Over an area of 36 km 2 of intertidal flats, at 12 sites, paired comparisons were made between seagrass-covered and nearby bare patches. Within seagrass meadows, dry mass of living seagrass was large and amounted to 180 ±10 g AFDM m - 2 (range 75-240). Containing twice the amount of silt per unit dry sediment mass, seagrass sediments were muddier than bare areas; the relative amount of organic material was also larger. The total number of species of bivalves and gastropods amounted to 27, 14 of which were found only in seagrass areas, 4 only in bare and 9 in both types of habitat. Among the three numerically most abundant species, the bivalves Anadara senilis, Dosinia hepatica and Loripes lacteus, the first was numerically most abundant in bare and the other two in seagrass-covered areas. Bare intertidal areas had greater mean total biomass of molluscs (80.5 g AFDM m - 2 ) than seagrass meadows (30.0 g AFDM m - 2 ). In both habitats, the bulk of the biomass was made up by A. senilis. Excluding this species, bare mudflats contained on average only 3.1 g AFDM m - 2 and seagrass meadows 6.9 g AFDM m - 2 . As compared to previous surveys in 1980-1986, the

Effets des sels organiques de tributyletain sur l'huître adulte Crassostrea gigas

OpenAIRE

Heral, Maurice; Alzieu, Claude; Caux, O.; Razet, Daniel; Garnier, Jacqueline

1983-01-01

La toxicité des composés organostanniques a été mise en évidence à l'égard de l'huître Crassostrea gigas tant aux stades larvaires (His & Robert, 1980) que chez l'adulte (Alzieu & al., 1980, 1981). Parallèlement ces mêmes auteurs ont montré l'accumulation d'étain dans les huîtres contaminées expérimentalement ainsi que le rôle que peut jouer le fluorure de TBT dans la perturbation de la croissance (Héral & al. 1981) et dans la malformation de la coquille des huîtres (Alzieu & al., 1981). Dans...

Behaviour of molluscs in cantabrian biota with respect to the activity present in the marine medium

International Nuclear Information System (INIS)

Montesinos, M.; Santos, A.M. de los

1981-01-01

The behaviour of molluscs with regard to the activity present in the marine medium is studied. For this purpose three large groups are considered, with special reference to their ecology and their particular mode of incorporating activity. Determinations are made of the total alpha and beta activity, as well as that due to elements such as 90 Sr, 137 Cs and natural U, in the organisms in question and in their eco-environment. A comparison is likewise established between the biocoenoses inhabiting Cantabrian and Mediterranean biota. (author)

PROPOSAL OF SANITARY MANAGEMENT OF EDIBLE ECHINODERMS IN SARDINIA

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G. Terrosu

2011-01-01

Full Text Available Sea urchin (Paracentrotus lividus is an edible echinoderm very common in the Mediterranean sea. In the Sardinian gastronomic tradition it represents a product very used in some periods of the year, but in practice the sanitary controls by the competent authorities are very difficult. The Reg. (EC n. 853/2004 provides that, as regards as the control on production, echinoderms are assimilable to live bivalve molluscs, with the exception of the provisions on purification. In this work a proposal for the sanitary management of the phases of gathering, transport and selling of the sea urchins has been studied.

[Radioecological studies of freshwater mollusks in the Chernobyl accident exclusion zone].

Science.gov (United States)

Gudkov, D I; Nazarov, A B; Dziubenko, E V; Kaglian, A E; Klenus, V G

2009-01-01

Species-specificity and dynamics of 90Sr, 137Cs and some transuranic elements accumulation in bivalve and gastropod freshwater molluscs of the Chernobyl exclusion zone during 1997-2008 was analyzed. The results of radiation dose and chromosome aberration rate estimation and the analysis of hemolymph composition of freshwater snail (Lymnaea stagnalis L.) was produced. The absorbed dose rate was registered in the range of 0.3-85.0 microGy/h. In closed water bodies the heightened chromosome aberration rate (up to 27%) in embryo tissues, and also the change of haematological indexes for the adult individuals of snails was registered.

The Role of the Cephalopod Digestive Gland in the Storage and Detoxification of Marine Pollutants

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Pedro M. Costa

2017-04-01

Full Text Available The relevance of cephalopods for fisheries and even aquaculture, is raising concerns on the relationship between these molluscs and environmental stressors, from climate change to pollution. However, how these organisms cope with environmental toxicants is far less understood than for other molluscs, especially bivalves, which are frontline models in aquatic toxicology. Although, sharing the same basic body plan, cephalopods hold distinct adaptations, often unique, as they are active predators with high growth and metabolic rates. Most studies on the digestive gland, the analog to the vertebrate liver, focused on metal bioaccumulation and its relation to environmental concentrations, with indication for the involvement of special cellular structures (like spherulae and proteins. Although the functioning of phase I and II enzymes of detoxification in molluscs is controversial, there is evidence for CYP-mediated bioactivation, albeit with lower activity than vertebrates, but this issue needs yet much research. Through novel molecular tools, toxicology-relevant genes and proteins are being unraveled, from metallothioneins to heat-shock proteins and phase II conjugation enzymes, which highlights the importance of increasing genomic annotation as paramount to understand toxicant-specific pathways. However, little is known on how organic toxicants are stored, metabolized and eliminated, albeit some evidence from biomarker approaches, particularly those related to oxidative stress, suggesting that these molluscs' digestive gland is indeed responsive to chemical aggression. Additionally, cause-effect relationships between pollutants and toxicopathic effects are little understood, thus compromising, if not the deployment of these organisms for biomonitoring, at least understanding how they are affected by anthropogenically-induced global change.

Monitoring the presence of domoic acid in the production areas of bivalve molluscs

Directory of Open Access Journals (Sweden)

Rachele Rossi

2016-09-01

Full Text Available Algal biotoxins, chemical compounds produced by some microscopic algae, constitute the phytoplankton. The mussels, feeding on phytoplankton, can accumulate these compounds to become themselves toxic. There have been several cases of food poisoning by consumption of contaminated shellfish. Such food poisoning have pushed our health care system to provide monitoring of shellfish in the framework of the monitoring plans carried out by AASSLL. In this paper we report the results obtained monitoring the presence of amnesic shellfish poisoning biotoxins, like domoic acid and its isomers, produced by Pseudonitzschia algae. The analyses were carried out by using both the high-performance liquid chromatography- ultraviolet official method and an experimental method performed with a time-offlight mass spectrometer (ESI-TOF. The 100% of samples analysed by the official method have always been below the limits of sensitivity (except one sample, and the 65% of samples analysed by ESI-TOF showed the presence of domoic acid.

Trace element determination in soft tissues of marine bivalves by activation analysis

International Nuclear Information System (INIS)

Fukushima, M.; Tamate, H.; Nakano, Y.

2003-01-01

Trace elements in soft tissues of marine bivalves were determined by neutron activation analysis (NAA) and photon activation analysis (PAA). Elemental levels of Ag, As, Br, Co, Cu, Fe, I, Mn, Ni, Rb, Se, and Zn in the organs of giant ezoscallos, rock oysters, and giant crams were obtained. The metal-bound proteins were extracted from the mantles and hepatopancreases of rock oysters. By irradiating the fraction obtained by HPLC gel chromatography, the possibility for the existence of an Ag bound protein in the mantles was found. (author)

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

Directory of Open Access Journals (Sweden)

Cédric Aria

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

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

Science.gov (United States)

Aria, Cédric; Caron, Jean-Bernard

2015-01-01

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

Optimal designs of mollusk shells from bivalves to snails.

Science.gov (United States)

Okabe, Takuya; Yoshimura, Jin

2017-02-10

Bivalve, ammonite and snail shells are described by a small number of geometrical parameters. Raup noted that the vast majority of theoretically possible shell forms do not occur in nature. The constraint factors that regulate the biased distribution of natural form have long since been an open problem in evolution. The problem of whether natural shell form is a result of optimization remains unsolved despite previous attempts. Here we solve this problem by considering the scaling exponent of shell thickness as a morphological parameter. The scaling exponent has a drastic effect on the optimal design of shell shapes. The observed characteristic shapes of natural shells are explained in a unified manner as a result of optimal utilization of shell material resources, while isometric growth in thickness leads to impossibly tight coiling.

Assessing phototoxicity of petroleum using the bivalve Mulinia lateralis and the mysid Mysidopsis bahia

International Nuclear Information System (INIS)

Pelletier, M.; Champlin, D.; Burgess, R.; Ho, K.; Kuhn-Hines, A.

1995-01-01

One of the major inputs of PAHs in the marine environment is petroleum products. A large and often catastrophic source of petroleum is an oil spill, which releases concentrated quantities of PAHs into the water column. Intermediate molecular weight compounds remain in the water column for a relatively extended length of time. These compounds include phototoxic PAHs such as anthracene, fluoranthene, pyrene, and their substituted derivatives. Assessments of the environmental impact of marine oil spills have not included phototoxicity tests using pelagic larvae of benthic invertebrates. In this study, the photoreactive toxicity of individual PAHs, including anthracene, pyrene, and fluoranthene, were determined using the bivalve, Mulinia lateralis and the mysid, Mysidopsis bahia. Ultraviolet light exposures increased toxicity relative to fluorescent light for both species but a particularly dramatic response was seen using M. lateralis embryos. This species was relatively insensitive when exposed under fluorescent lights, but exhibited up to a 4,000 fold increase in toxicity under ultraviolet lights. Exposures with different types of petroleum (e.g., fuel oil number-sign 2 and crude oil) under fluorescent and ultraviolet light will demonstrate the utility of this bivalve and mysid for assessing oil spill-related acute and sublethal toxicity in the marine environment

High mobility group protein DSP1 negatively regulates HSP70 transcription in Crassostrea hongkongensis

Energy Technology Data Exchange (ETDEWEB)

Miao, Zongyu; Xu, Delin; Cui, Miao; Zhang, Qizhong, E-mail: zhangqzdr@126.com

2016-06-10

HSP70 acts mostly as a molecular chaperone and plays important roles in facilitating the folding of nascent peptides as well as the refolding or degradation of the denatured proteins. Under stressed conditions, the expression level of HSP70 is upregulated significantly and rapidly, as is known to be achieved by various regulatory factors controlling the transcriptional level. In this study, a high mobility group protein DSP1 was identified by DNA-affinity purification from the nuclear extracts of Crassostrea hongkongensis using the ChHSP70 promoter as a bait. The specific interaction between the prokaryotically expressed ChDSP1 and the FITC-labeled ChHSP70 promoter was confirmed by EMSA analysis. ChDSP1 was shown to negatively regulate ChHSP70 promoter expression by Luciferase Reporter Assay in the heterologous HEK293T cells. Both ChHSP70 and ChDSP1 transcriptions were induced by either thermal or CdCl{sub 2} stress, while the accumulated expression peaks of ChDSP1 were always slightly delayed when compared with that of ChHSP70. This indicates that ChDSP1 is involved, very likely to exert its suppressive role, in the recovery of the ChHSP70 expression from the induced level to its original state. This study is the first to report negative regulator of HSP70 gene transcription, and provides novel insights into the mechanisms controlling heat shock protein expression. -- Highlights: •HMG protein ChDSP1 shows affinity to ChHSP70 promoter in Crassostrea hongkongensis. •ChDSP1 negatively regulates ChHSP70 transcription. •ChHSP70 and ChDSP1 transcriptions were coordinately induced by thermal/Cd stress. •ChDSP1 may contribute to the recovery of the induced ChHSP70 to its original state. •This is the first report regarding negative regulator of HSP70 transcription.

Impacts of ocean acidification on gene expression and biomineralisation in the Pacific oyster Crassostrea gigas Thunberg, 1793

Science.gov (United States)

Bagusche, F.; Pouvreau, S.; Trueman, C.; Long, S.; Hauton, C.

2012-04-01

The published evidence of impacts of ocean acidification and on marine calcifiers has emphasized the need to understand the molecular mechanisms of biomineralisation. Crassostrea gigas is an ideal organism to examine these processes as: 1) the hatchery rearing of larval stages is well constrained, 2) studies have established an ontogenetic switch in deposition of carbonate polymorphs from aragonite in larval shells to calcite in adults and 3) it is a globally-important commercial species. Research summarized in this presentation will identify some of the molecular mechanisms involved in calcification processes during ontogeny of Crassostrea gigas, as well as possible impacts of changes in environmental conditions such as temperature and pH. Data will be presented from a quantitative real-time PCR study of the changes in gene expression during development in different environments. Additionally scanning electron microscopy and infrared spectroscopy analyses of shell microstructures and composition will be summarised to correlate changes in gene expression with end-point differences in shell structure. Preliminary results suggest that changes in the environmental conditions lead to differences in expression patterns of genes involved in biomineralisation processes. The combined effects of ambient seawater temperature and low pH show the greatest negative effect on larval shell development, identified as malformations, eroded shell surfaces and a significant decrease in shell size. However, the effect of higher seawater temperature seems to amend the effects of ocean acidification on larval shell development.

Microbiological quality of oysters (Crassostrea gigas) produced and commercialized in the coastal region of Florianópolis - Brazil

OpenAIRE

Pereira,Murilo Anderson; Nunes,Márcia Menezes; Nuernberg,Leonardo; Schulz,Denys; Batista,Cleide Rosana Vieira

2006-01-01

Oysters are filter feeders able to ingest particles in suspension that may carry pathogenic microorganisms. In this respect, the consumption of raw oysters can cause foodborne diseases in humans. The aim of the present study was to evaluate the microbiological quality of Crassostrea gigas oysters cultivated and commercialized in the coastal region of Florianópolis, SC, Brazil. The study comprised counts of coliforms at 35ºC and at 45ºC, Escherichia coli and coagulase-positive staphylococci, a...

Spatial distribution in a temperate coastal ecosystem of the wild stock of the farmed oyster Crassostrea gigas (Thunberg)

OpenAIRE

Cognie, B; Haure, Joel; Barille, L

2006-01-01

The Pacific oyster, Crassostrea gigas, well known throughout the world because of its ability to adapt to a wide range of environmental conditions, was introduced for cultivation into France on a massive scale in the 1970s. With global warming, the reproductive population, confined at the beginning to the south of the French Atlantic coast, became established at more northern latitudes (above 45 degrees 58'N), and wild C gigas began to colonize coastal areas such as our study site, Bourgneuf ...

ESR-dating of subfossil mollusc shells: the problem of absorbed paleodose fading

International Nuclear Information System (INIS)

Molod'kov, A.

1988-01-01

Detailed investigation of paleodosimetric prperties of subfossil mollusc shells has been carried out with respect to their dating by ESR-spectroscopy. Attention has been paid to the connection between the absorbed paleodose value and factors on the upper dating limit. Energetic parameters of the CO 3 3- centres have been determined in the calcareous shell skeleton serving as a paleodetector: E=1.515 eV, ν 0 =8x10 13 s -1 , τ=1.14x10 6 years at 5 deg C. Mathematical models have been elaborated for the accumulation of paleodose in natural conditions. New paleodosimetric equations proposed for calculating the age of shells and some minerals may be applied both to ESR- and thermoluminescence-dating. The proposed method enables one to date the shells within the time span of nx10 2 -nx10 6 years

Concentration of Organochlorine and Organophosphorus Pesticides in Different Molluscs from Tighra Reservoir, Gwalior, India.

Science.gov (United States)

Mamta; Rao, R J; Wani, Khursheed Ahmad

2015-09-01

Concentration of organochlorine and organophosphorus pesticides and their metabolites were determined in whole body homogenate of L. acuminata, I. exustus, V. dissimilis, V. bengalensis, from Tighra Reservoir during summer and post monsoon season using GC-MS technique. The different types of pesticides viz., HCB, heptachlor, aldrin, endosulfan, dieldrin, p,p-DDT, choloropyrifos, methyl parathion, dicholorovos, ethion, malathion, parathion were found in resident molluscs studied. Concentration of these pesticides varied independently during the summer and the post monsoon season at monitored sites. The study concluded that presence of pesticides in Tighra Reservoir is a major concern on public and ecosystem health and use of biopesticides in the adjacent area of Reservoir is highly recommended.

Major and c-series gangliosides in lenticular tissues: mammals to molluscs.

Science.gov (United States)

Saito, M; Sugiyama, K

2001-10-01

Gangliosides of eye lenses were examined in mammals (rat, rabbits, pig, cow), bird (chicken), reptile (terrapin), amphibian (bullfrog), bony fish (red sea bream, bluefin tuna, bonito, Pacific mackerel) and molluscs (common squid, Pacific octopus). Besides the fact that GM3 was the common ganglioside species, the composition of major gangliosides in mammalian eye lenses significantly differed from each other. While gangliotetraose gangliosides were abundant in rat eye lens, they did not constitute major components in porcine and bovine tissues. The c-series ganglioside GT3 was expressed in rat eye lenses but were practically absent in other mammalian tissues. The composition of major gangliosides in eye lenses of lower animals varied from species to species, whereas c-series gangliosides were consistently expressed, showing similar compositional profiles. Our results demonstrate the species-specific compositions of lenticular gangliosides. Evidence was also provided suggesting that eye lenses of common squid (Todarodes pacificus) and Pacific octopus (Octopus vulgaris) express gangliosides including gangliotetraose species and c-series gangliosides.

Menadione Sodium Bisulphite (MSB) enhances the resistance response of tomato, leading to repel mollusc pests.

Science.gov (United States)

Carrillo-Perdomo, Estefanía; Jiménez-Arias, David; Aller, Ángel; Borges, Andrés A

2016-05-01

Snails and slugs are terrestrial gastropods representing an important biotic stress that adversely affects crop yields. These pests are typically controlled with molluscicides, which produce pollution and toxicity and further induce the evolution of resistance mechanisms, making pest management even more challenging. In our work, we have assessed the efficacy of two different plant defence activators, menadione sodium bisulphite (MSB) and 1,2,3-benzothiadiazole-7-thiocarboxylic acid S-methyl ester (BTH), as inducers of resistance mechanisms of the model plant for defence, Solanum lycopersicum, against the generalist mollusc Theba grasseti (Helicidae). The study was designed to test the feeding behaviour and choice of snails, and also to analyse the expression profile of different genes specifically involved in defence against herbivores and wounds. Our data suggest that, through the downregulation of the terpene volatile genes and the production of proteinase inhibitors, treated MSB plants may be less apparent to herbivores that use herbivore-induced plant volatiles for host location. By contrast, BTH was not effective in the treatment of the pest, probably owing to an antagonistic effect derived from the induction of both salicylic-acid-dependent and jasmonic-acid-dependent pathways. This information is crucial to determine the genetic basis of the choice of terrestrial gastropod herbivores in tomato, providing valuable insight into how the plant defence activators could control herbivore pests in plants. Our work not only reports for the first time the interaction between tomato and a mollusc pest but also presents the action of two plant defence inductors that seems to produce opposed responses by inducing resistance mechanisms through different defence pathways. © 2015 Society of Chemical Industry.

The quagga mussel (Dreissena rostriformis bugensis Andrusov, 1897) – another Ponto-Caspian dreissenid bivalve in the southern Baltic catchment: the first record from the Szczecin Lagoon

OpenAIRE

Adam Woźniczka; Brygida Wawrzyniak-Wydrowska; Teresa Radziejewska; Anna Skrzypacz

2016-01-01

In 2014, a non-indigenous dreissenid bivalve, the quagga mussel (Dreissena rostriformis bugensis Andrusov, 1897) was for the first time recorded in the Szczecin Lagoon. This was also the first record of the species in the Baltic Sea catchment. The quagga mussel was found to accompany the zebra mussel (Dreissena polymorpha), a non-indigenous bivalve already firmly established in the Lagoon. As indicated by the new immigrant's estimated abundance (4000.0 ± 355.44 ind. m−2) and the zebra mussel ...

Metal accumulation in marine bivalves under various tributyltin burdens.

Science.gov (United States)

Tang, Chuan-Ho; Lin, Chan-Shing; Wang, Wei-Hsien

2009-11-01

In the present study, a field survey was conducted to measure the accumulation of butyltin, Cu, Zn, and Cd in green mussels (Perna viridis) and Pacific oysters (Crassostrea gigas) at the regions along a tributyltin pollution gradient. A negative correlation was found between the tributyltin/total butyltin ratio (0.87-0.31) and tributyltin content (114-5,817 ng/g as tin dry wt) in oysters, while the Cu content (44.2-381 mg/kg dry wt) was positively correlated with the logarithm of tributyltin content during the summer and winter. This suggests that as the tributyltin burden increases, the rates of tributyltin metabolism may be elevated, leading to enhanced Cu accumulation. A similar accumulation pattern for Zn was also found in oysters. In mussels, however, the tributyltin/total butyltin ratio and the Cu and Zn contents remained relatively constant (~ 0.7, 12, and 100 mg/kg dry wt, respectively) regardless of the tributyltin burden. Clearly, the butyltin and Cu/Zn accumulation processes in oysters differ from those in mussels under tributyltin pollution. These observations provide valuable information for those who evaluate or compare tributyltin and/or Cu/Zn pollution using oysters and mussels as bioindicators.

Diversity patterns and freshwater molluscs similarities in small water reservoirs

Directory of Open Access Journals (Sweden)

Tomáš Čejka

2011-02-01

Full Text Available The survey presents the molluscan fauna from six impoundment systems of two sides (NW and SE of the Small Carpathians. Altogether 25 species (15 gastropod and 10 bivalve species were identified in reservoirs and their subsystems (inflows and outlets. The number of species per site ranged from 2 to 12, the mean number of species per site was 7. The mean number of individuals per site ranged from 15 to 905 (mean 174 ind/m2. Radix auricularia, R. ovata, Gyraulus albus, Gyraulus parvus/laevis, Hippeutis complanatus and Pisidium casertanum were present in more than 50% of reservoirs. The most abundant and frequent species in the entire area and all subsystems were Pisidium casertanum, Pisidium subtruncatum and Gyraulus parvus/laevis. Faunistic similarity indices indicate moderate degree of beta diversity i.e., differentiation among the sites; good separation of sites by cluster analysis indicates a different composition among inflows/outlets and littoral molluscan faunas of reservoirs.

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

OpenAIRE

Cranford, Peter J.; Kamermans, Pauline; Krause, Gesche; Mazurie, Joseph; Buck, Bela H.; Dolmer, Per; Fraser, David; Van Nieuwenhove, Kris; O'Beirn, Francis X.; Sanchez-mata, Adoracion; Thorarinsdottir, Gudrun G.; Strand, Oivind

2012-01-01

An ecosystem-based approach to bivalve aquaculture management is a strategy for the integration of aquaculture within the wider ecosystem, including human aspects, in such a way that it promotes sustainable development, equity, and resilience of ecosystems. Given the linkage between social and ecological systems, marine regulators require an ecosystem-based decision framework that structures and integrates the relationships between these systems and facilitates communication of aquaculture–en...

Characteristic crystal orientation of folia in oyster shell, Crassostrea gigas

Energy Technology Data Exchange (ETDEWEB)

Lee, Seung Woo [Department of Chemical and Biomolecular Engineering, Sogang University, Seoul (Korea, Republic of); Kim, Gyeung Ho [Nano-Materials Reserch Center, Korea Institute of Science and Technology, Seoul (Korea, Republic of); Choi, Cheong Song [Department of Chemical and Biomolecular Engineering, Sogang University, Seoul (Korea, Republic of)], E-mail: cschoi@sogang.ac.kr

2008-03-10

The thin sheets of calcite, termed folia, that make up much of the shell of an oyster are composed of foliated lath. Folia of the giant Pacific oyster (Crassostrea gigas) were examined using TEM (transmission electron microscopy) and tested using microindentation and nanoindentation techniques. Analysis of the Kikuchi patterns obtained from the folia showed that there are two types (type I and type II) of preferred orientation, with an angle of around 70{sup o} between them. Nanoindentation tests showed that the folia exhibit a hardness of about 3 GPa and elastic modulus of about 73 GPa. Microcracks were generated using a microindenter in order to study the fracture mechanisms of the folia. Following on from these investigations, fracture mechanisms are discussed in conjunction with the correlation between preferred orientation and structural characteristics during cracking of the folia. Comparing the morphology and the polymorphism with nacre (also known as mother of pearl), the advantages of the relatively fast crystal growth and less amount of organic matrix in folia may have interesting implications for the development of sophisticated synthetic materials.

Detection of Toxoplasma gondii DNA in Brazilian oysters (Crassostrea rhizophorae).

Science.gov (United States)

Ribeiro, L A; Santos, L K N S S; Brito, P A; Maciel, B M; Da Silva, A V; Albuquerque, G R

2015-05-04

The aim of this study was to detect evidence of Toxoplasma gondii using polymerase chain reaction (PCR)-based techniques in oysters (Crassostrea rhizophorae) obtained from the southern coastal region of Bahia, Brazil. A total of 624 oysters were collected, and the gills and digestive glands were dissected. Each tissue sample was separated into pools containing tissues (of the same type) from three animals, leading to a total of 416 experimental samples for analysis (208 samples each from the gills and digestive glands). Molecular analysis using PCR-based detection of the T. gondii AF 146527 repetitive fragment yielded negative results for all samples. However, when nested-PCR was used for detection of the T. gondii SAG-1 gene, 17 samples were positive, with the gills being the tissue with maximal detection of the parasite. These positive results were confirmed by sample sequencing. It is therefore suggested that C. rhizophorae oysters are capable of filtering and retaining T. gondii oocysts in their tissue. This represents a risk to public health because they are traditionally ingested in natura.

108mAg and 110mAg in crassostrea gigas

International Nuclear Information System (INIS)

Ishikawa, Y.; Sato, N.; Nakamura, E.; Sekine, T.; Yoshihara, K.

1992-01-01

Accumulation of radiosilver 108m Ag and 110m Ag in oysters (Crassostrea gigas) and their behavior in marine environments has been studied in the northeast Pacific coast in Japan. Enrichment of radiosilver in oysters depends on topographical conditions; significant bioaccumulation occurred in open bays, while it was hardly observed in bays with narrow shaped entrances. From these observations difference of the behavior of radiosilver between open and nearly closed bays is suggested. 110m Ag in oysters decayed with an effective half-life of about 150 days for both the Chinese nuclear weapon test and the Chernobyl accident. In contrast to radiosilver, the fission product nuclide 137 Cs was almost independent of topographical conditions, and its concentration was constant. 110m Ag bioaccumulation in oysters after the Chernobyl accident in 1986 was found in both open and nearly closed bays, the lattershowing much lower concentration of radiosilver than the former. Specific activity of 108m Ag in oysters was determined in bays open to the Pacific Oceans. (author) 13 refs.; 4 figs.; 3 tabs

Studies on the distribution of 210Po and 210Pb in the ecosystem of Point Calimere Coast (Palk Strait), India

International Nuclear Information System (INIS)

Suriyanarayanan, S.; Brahmanandhan, G.M.; Malathi, J.; Ravi Kumar, S.; Masilamani, V.; Shahul Hameed, P.; Selvasekarapandian, S.

2008-01-01

A systematic study on the natural radionuclides such as 210 Po and 210 Pb in the environmental matrices of Point Calimere ecosystem has been undertaken to establish a baseline data on the radiation profile of Point Calimere environment. The environmental samples such as water, sediment and biota (seaweeds, crustaceans, molluscs and fish) have been subjected to analyses. It has been observed that the concentration of 210 Po and 210 Pb in the water samples of Point Calimere to be 0.5 mBq/l and 1.3 mBq/l, respectively. The soft tissues of the organisms accumulated higher 210 Po content while shells and bones contained more 210 Pb. The bivalve molluscs Meretrix casta have been identified to accumulate higher concentration of 210 Po suggesting that they could serve as bio-indicator of radionuclides like 210 Po in the Point Calimere ecosystem. The concentration factor of 210 Po for the biotic components ranged from ∼10 3 to 10 6 while for 210 Pb it ranged from ∼10 3 to 10 5

INVESTIGATIONS INTO THE EFFECTS OF SEASON AND WATER QUALITY ON OYSTERS (CRASSOSTREA VIRGINICA) AND ASSOCIATED FISH ASSEMBLAGES IN THE CALOOSAHATCHEE RIVER ESTUARY, FLORIDA: IMPLICATIONS OF ALTERED FRESHWATER INFLOW

Science.gov (United States)

A suite of biological and ecological responses of a Valued Ecosystem Component species, Crassostrea virginica, was used to investigate ecosystem-wide health effects of watershed alterations in the Caloosahatchee River estuary, Florida. The influence of water quality and season on...

Relationship between anti-oxidant capacity and manganese accumulation in the soft tissues of two freshwater molluscs: Unio pictorum mancus (Lamellibranchia, Unionidae and Viviparus ater (Gastropoda, Prosobranchia

Directory of Open Access Journals (Sweden)

Oscar RAVERA

2005-08-01

Full Text Available Manganese is an element of great importance in the life cycle of plants and animals. For example, it plays an essential role as an activator of various enzymatic systems such as isoenzymes of superoxide dismutase. Freshwater Unionidae concentrate relatively large amounts of manganese in their tissues, but little is known about the physiological role of this metal. The aim of this research is to acquire a better knowledge of the role of manganese in molluscs which accumulate large amounts of this metal and in those with low manganese concentrations. As manganese is one of the metals present in the superoxide molecule, the possible relationship between manganese concentration in the soft tissues of molluscs and the antioxidant capacity of the metal can usefully be tested. To this end two species of molluscs were analysed: Unio pictorum mancus (Lamellibranchia, Unionidae, which is very rich in manganese, and Viviparus ater (Gastropoda, Prosobranchia which has a low manganese content. The adults of both species were analysed for manganese concentration by ICP, and for antioxidant capacity as RAC (Relative Antioxidant Capacity by a superoxide dismutase method. The results clearly demonstrate the active role played by manganese against free radicals and consequently the important role of the metal in protecting Unio against oxidative stress. The low concentration of manganese in Viviparus may be the result of the effective excretion of this metal, as was found for ruthenium.

Structural determination of the carbohydrate chains from arthropod and mollusc hemocyanin by means of 500-MHz 1H-NMR spectroscopy

International Nuclear Information System (INIS)

Kuik, J.A. van.

1987-01-01

In this thesis carbohydrate structures of hemocyanins of arthropods and molluscs are studied. Hemocyanins are high-molecular-mass, copper-containing oxygen-transport proteins. The function of these carbohydrate chains are yet still unknown. It is not probable that they play a role in the oxygen-binding processes. They are rather thought to have a function in the build-up of the hemocyanin molecules. 286 refs.; 30 figs.; 25 tabs

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

Marine Biotoxins: Occurrence, Toxicity, Regulatory Limits and Reference Methods

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Pierina Visciano

2016-07-01

Full Text Available Harmful algal blooms are natural phenomena caused by the massive growth of phytoplankton that may contain highly toxic chemicals, the so-called marine biotoxins causing illness and even death to both aquatic organisms and humans. Their occurrence has been increased in frequency and severity, suggesting a worldwide public health risk. Marine biotoxins can accumulate in bivalve molluscs and regulatory limits have been set for some classes according to European Union legislation. These compounds can be distinguished in water- and fat-soluble molecules. The first group involves those of Paralytic Shellfish Poisoning and Amnesic Shellfish Poisoning, whereas the toxins soluble in fat can cause Diarrheic Shellfish Poisoning and Neurotoxic Shellfish Poisoning. Due to the lack of long-term toxicity studies, establishing tolerable daily intakes for any of these marine biotoxins was not possible, but an acute reference dose can be considered more appropriate, because these molecules show an acute toxicity. Dietary exposure assessment is linked both to the levels of marine biotoxins present in bivalve molluscs and the portion that could be eaten by consumers. Symptoms may vary from a severe gastrointestinal intoxication with diarrhea, nausea, vomiting, and abdominal cramps to neurological disorders such as ataxia, dizziness, partial paralysis, and respiratory distress. The official method for the detection of marine biotoxins is the mouse bioassay (MBA showing some limits due to ethical restrictions and insufficient specificity. For this reason, the liquid chromatography–mass spectrometry method has replaced MBA as the reference technique. However, the monitoring of algal blooms producing marine biotoxins should be regularly assessed in order to obtain more reliable, accurate estimates of bloom toxicity and their potential impacts.

Radionuclide transfer to freshwater biota species: review of Russian language studies

International Nuclear Information System (INIS)

Fesenko, S.; Fesenko, J.; Sanzharova, N.; Karpenko, E.; Titov, I.

2011-01-01

Around 130 publications reporting studies on radionuclide transfer to freshwater biota species conducted in the former USSR were reviewed to provide the concentration ratio values. None of these studies were available up to now in the English language reviews or publications. The values derived have been compared with the CR values used for freshwater systems in the International reviews. For some radionuclides reviewed in this paper, the data are in good agreement with the mean CR values presented earlier, however for some of them, in particular, for 241 Am (bivalve molluscs, gastropods and pelagic fish), 60 Co (gastropods, benthic fish and insect larvae), 90 Sr and 137 Cs (benthic fish and zooplankton), the mean values given here are substantially different from those presented earlier. The data reported in this paper for thirty five radionuclides and eleven groups of freshwater species markedly improve the extent of available data for evaluation of radiation impact on freshwater species. - Research highlights: → The paper provides information on concentration ratios to freshwater biota species for 35 radionuclides. Many of the data are for 90 Sr and 137 Cs. → For the majority of radionuclides reviewed in this paper, the CR values are in good agreement with those given in the recent International reviews. → For 241 Am (bivalve molluscs, gastropods and pelagic fish), 60 Co (gastropods, benthic fish and insect larvae), 90 Sr and 137 Cs (benthic fish and zooplankton), the mean values based on review of the Russian language publications are substantially different from those presented in the International reviews. → Information presented in the paper significantly increases the availability of data on radionuclide accumulation in freshwater species.

Characterization of South American Snails of the Genus Biomphalaria (Basommatophora: Planorbidae and Schistosoma mansoni (Platyhelminthes: Trematoda in Molluscs by PCR-RFLP

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Roberta Lima Caldeira

2016-01-01

Full Text Available The identification of snails of the genus Biomphalaria can be done using morphological characteristics which depends on the size of the snails and skill and knowledge of researcher. These methods sometimes are not adequate for identification of species. The PCR-RFLP, using the ITS region of the rDNA, has been used to identify Brazilian species of the genus Biomphalaria. Nevertheless, there is a lack of information about snails from other Latin American countries. In addition, some snails may be infected by Schistosoma mansoni and when submitted to PCR-RFLP they show molecular profiles different from those previously standardized for the other mollusc species. In this work the molecular profiles of 15 species and the subspecies were established by PCR-RFLP of ITS-rDNA with the enzyme DdeI. Moreover, the molecular profiles of host species, B. glabrata, B. straminea, B. tenagophila, and B. prona, infected by S. mansoni were also established. The molluscs were dissected to permit morphological identification. These results contribute to a correct identification of snails of the genus Biomphalaria and detection of these snails infected by S. mansoni.

Ministry of Health Circular No. 36 on the physical requirements for marine waters intended for mollusc culture (Section 12 of Act No. 192 of 2 May 1977 and Section 5 of Ministerial Decree of 27 April 1978)

International Nuclear Information System (INIS)

1979-01-01

This Circular by the Minister of Health follows up a Ministerial Decree of 27 April 1978 made in implementation of the 1977 Act on health protection standards for the production of and trade in molluscs. It fixes the microbiological, biological, chemical and physical quality requirements for waters intended for molluscs culture and production. These include radionuclide concentrations which must not exceed the limits laid down by Presidential Decree No. 185 of 13 February 1964 on radiation protection. (NEA) [fr

THE SECTION OF TORRE PICCHIO (TERNI, UMBRIA, CENTRAL ITALY:A VILLAFRANCHIAN SITE RICH IN VERTEBRATES, MOLLUSCS,OSTRACODS AND PLANTS

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ODOARDO GIROTTI

2003-03-01

Full Text Available Fluvial deposits of the S. Maria di Ciciliano Formation crop out near Montecastrilli (Terni, in the southwestern branch of the Tiberino Basin.  Many specimens of plants ("mummified" woods, fruits and seeds, freshwater molluscs, ostracods, vertebrate bones and coprolites were collected at Torre Picchio. This small outcrop contains a fairly rich record of fruits and seeds, among which about 50 species were identified; the most frequent invariably belong to submerged, floating and emergent aquatic herbs, possibly because these were buried not far from their place of growth, thus representing the ancient local vegetation.  The fruits and seeds of woody plants, including several exotic elements, were transported from neighbouring areas and indicate a paleoclimate similar to the present day, though slightly wetter.  Among molluscs, three distinct assemblages were found, indicating fluvial, swampy and lacustrine environment, respectively.  They contain taxa of biochronological interest, most of them typical of Early Pleistocene deposits (late Villafranchian, but making their first appearance in the Late Pliocene (Middle Villafranchian. One species, Margarifera (Pseudunio auricularia, represents the oldest record everywhere, since it was known, so far, only from the Middle Pleistocene upwards.  As palaeoenvironmental indicators, the ostracods complete the information given by molluscs.  Vetrebrates are represented by large and small mammals, rare birds, reptiles, amphibians and some fishes.  A great number of coprolites was collected as well.  The mammal assemblage shows affinities with the Costa S. Giacomo and Olivola F. U. (Middle and Late Villafranchian, Late Pliocene. Mimomys medasensis, an Iberoccitane element, is signaled for the first time in Italy.  From the geological point of view, the S. Maria di Ciciliano Fm. is interfingering with the marine Chiani-Tevere Fm., which is mostly Santernian in age and lies unconformably on the Middle

Subcellular compartmentalization of Cd and Zn in two bivalves. II. Significance of trophically available metal (TAM)

Science.gov (United States)

Wallace, W.G.; Luoma, S.N.

2003-01-01

This paper examines how the subcellular partitioning of Cd and Zn in the bivalves Macoma balthica and Potamocorbula amurensis may affect the trophic transfer of metal to predators. Results show that the partitioning of metals to organelles, 'enzymes' and metallothioneins (MT) comprise a subcellular compartment containing trophically available metal (TAM; i.e. metal trophically available to predators), and that because this partitioning varies with species, animal size and metal, TAM is similarly influenced. Clams from San Francisco Bay, California, were exposed for 14 d to 3.5 ??g 1-1 Cd and 20.5 ??g 1-1 Zn, including 109Cd and 65Zn as radiotracers, and were used in feeding experiments with grass shrimp Palaemon macrodatylus, or used to investigate the subcellular partitioning of metal. Grass shrimp fed Cd-contaminated P. amurensis absorbed ???60% of ingested Cd, which was in accordance with the partitioning of Cd to the bivalve's TAM compartment (i.e. Cd associated with organelles, 'enzymes' and MT); a similar relationship was found in previous studies with grass shrimp fed Cd-contaminated oligochaetes. Thus, TAM may be used as a tool to predict the trophic transfer of at least Cd. Subcellular fractionation revealed that ???34% of both the Cd and Zn accumulated by M. balthica was associated with TAM, while partitioning to TAM in P. amurensis was metal-dependent (???60% for TAM-Cd%, ???73% for TAM-Zn%). The greater TAM-Cd% of P. amurensis than M. balthica is due to preferential binding of Cd to MT and 'enzymes', while enhanced TAM-Zn% of P. amurensis results from a greater binding of Zn to organelles. TAM for most species-metal combinations was size-dependent, decreasing with increased clam size. Based on field data, it is estimated that of the 2 bivalves, P. amurensis poses the greater threat of Cd exposure to predators because of higher tissue concentrations and greater partitioning as TAM; exposure of Zn to predators would be similar between these species.

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

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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

Observations of Crassostrea virginica cultured in the heated effluent and discharged radionuclides of a nuclear power reactor

International Nuclear Information System (INIS)

Price, A.H.; Hess, C.T.; Smith, C.W.

1976-06-01

American oysters (Crassostrea virginica) were rafted for 26 months at four sites in the effluent waters near Maine Yankee Nuclear Power Reactor in Montsweag Bay and at a control site in the adjacent Damariscotta River. In an evaluation of the thermal effluent for aquaculture, comparisons are made among the sites of the effects of heated effluent on oyster growth and condition, and the uptake and retention of gamma-ray emitting radionuclides. Growth and uptake of radionuclides were observed to be accelerated at the warmer water sites. Both experimental results and calculations for 58 Co and 54 Mn are presented

Disease and disorders of freshwater unionid mussels: a brief overview of recent studies

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Francesca Carella

2016-11-01

Full Text Available The use of aquatic invertebrates in biomedical research and as environmental sentinels has dramatically grown in recent decades, with an increased need in understanding of comparative pathology. The Unionids freshwater mussels are a group of worldwide distributed bivalves residing small ditches and ponds, lakes, canals and rivers, often used as animal test in eco-toxicological studies. Once one of the most abundant bivalve molluscs in ancient rivers around the world, now many of them are declining in many countries and consequently are nearly extinct in many areas. The causes of this decline are not fully understood but alteration and degradation of the freshwater habitat seemed to play a central role. To date, link causality to the observed losses during episode of mussel die-offs has been more difficult to establish, and disease and pathogen presence have been scarcely considered. In this article we provide a brief overview of unionids freshwater mussel conservation status, also describing reported diseases and pathogens and illustrating a few relatively well-documented studies.

Mesocosm validation of the marine No Effect Concentration of dissolved copper derived from a species sensitivity distribution.

Science.gov (United States)

Foekema, E M; Kaag, N H B M; Kramer, K J M; Long, K

2015-07-15

The Predicted No Effect Concentration (PNEC) for dissolved copper based on the species sensitivity distribution (SSD) of 24 marine single species tests was validated in marine mesocosms. To achieve this, the impact of actively maintained concentrations of dissolved copper on a marine benthic and planktonic community was studied in 18 outdoor 4.6m(3) mesocosms. Five treatment levels, ranging from 2.9 to 31μg dissolved Cu/L, were created in triplicate and maintained for 82days. Clear effects were observed on gastropod and bivalve molluscs, phytoplankton, zooplankton, sponges and sessile algae. The most sensitive biological endpoints; reproduction success of the bivalve Cerastoderma edule, copepod population development and periphyton growth were significantly affected at concentrations of 9.9μg Cu/L and higher. The No Observed Effect Concentration (NOEC) derived from this study was 5.7μg dissolved Cu/L. Taking into account the DOC concentration of the mesocosm water this NOEC is comparable to the PNEC derived from the SSD. Copyright © 2015. Published by Elsevier B.V.

Shellfish depuration by gamma irradiation: Final report for the period October 1, 1985-September 30, 1986

International Nuclear Information System (INIS)

Beghian, L.; Melnick, J.

1986-01-01

Irradiation of live bivalve molluscs is a promising new technique to reduce the public health threats of viral and bacterial pathogens in the consumption of raw shellfish. In studies conducted within the past year, live hardshelled clams and oysters were innoculated with Simian Rotavirus SA-11, Poliovirus I, and Hepatitis-A virus and treated with gamma ray ionizing radiation from University of Lowell/DOE 800,000 Curie 60 Co source over a dose range of 0.5--10 kiloGray (50--1000 kilorad) to determine the effectiveness of the process in eliminating viral activity and thus easing the potential viral health threats associated with uncooked bivalves. Two viral strains, SA-11 and Poliovirus I, were employed as models to perfect laboratory technique and to estimate the most appropriate range of dose exposures necessary for optimal inactivation of the infectious pathogen, Hepatitis A. Post-irradiation survivorship of the oysters and quahogs was assessed over a range of exposures, and showed an exceptionally high degree of radioresistance for these molluscan species. 7 refs., 7 figs., 14 tabs

Shellfish depuration by gamma irradiation: Final report for the period October 1, 1985-September 30, 1986

Energy Technology Data Exchange (ETDEWEB)

Beghian, L.; Melnick, J.

1986-11-01

Irradiation of live bivalve molluscs is a promising new technique to reduce the public health threats of viral and bacterial pathogens in the consumption of raw shellfish. In studies conducted within the past year, live hardshelled clams and oysters were innoculated with Simian Rotavirus SA-11, Poliovirus I, and Hepatitis-A virus and treated with gamma ray ionizing radiation from University of Lowell/DOE 800,000 Curie /sup 60/Co source over a dose range of 0.5--10 kiloGray (50--1000 kilorad) to determine the effectiveness of the process in eliminating viral activity and thus easing the potential viral health threats associated with uncooked bivalves. Two viral strains, SA-11 and Poliovirus I, were employed as models to perfect laboratory technique and to estimate the most appropriate range of dose exposures necessary for optimal inactivation of the infectious pathogen, Hepatitis A. Post-irradiation survivorship of the oysters and quahogs was assessed over a range of exposures, and showed an exceptionally high degree of radioresistance for these molluscan species. 7 refs., 7 figs., 14 tabs.

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.

Using transplanted bivalves to assess oil exposure and effects in Delaware Bay

International Nuclear Information System (INIS)

Salazar, M.; Salazar, S.; Mearns, A.; Venosa, A.; Eberhart, B.

1995-01-01

To evaluate the effectiveness of bioremediation, the US EPA oiled intertidal plots in Delaware Bay and monitored oil degradation rates. This controlled release of oil was also used to test the utility of transplanted bivalves in assessing oil spills and to evaluate the extent and potential effects of the release. Measuring the accumulation of oil in bivalve tissues was used to estimate exposure and the extent of contamination. Growth was used to estimate potential bioeffects. Approximately 1,800 mussels and 1,200 oysters were transplanted to 11 intertidal sites. Five treatment sites were within 1 meter of the lower end of the oiled plots. A total of six sites were used as controls, three on either side of the oiled plots at 5, 10, and 100 m. Samples were taken on Day 0, 2, 15, and 28 to estimate the rate of bioaccumulation. All of the mussels died within the first week of exposure; oysters exhibited over 95% survival but growth was minimal. The authors found a statistically significant difference in tissue weights when comparing treatment sites with control sites. The total concentration of polynuclear aromatic hydrocarbons (PAHs) in tissues of oysters nearest the oiled plots increased by a factor of four after an exposure period of two days. PAH concentrations in control oysters nearest the mouth of the bay increased slightly but the differences were not statistically significant. The control oysters nearest the head of the bay received an intermediate dose which was depurated by the end of the 28-day experiment. PAHs in the oysters nearest the oiled plots approached but did not return to background levels by the end of the test

Korean mega-tidal environments and tidal power projects: Korean tidal flats - biology, ecology and land uses by reclamations and other feasibilities

International Nuclear Information System (INIS)

Koh, C.H.

1997-01-01

The western coast of Korea is characterized by a regime of strong tides. Coastal uses can be projected in various ways: fisheries, shipping, harbor and military activities and also for tide power. The building of the barrage between Ansan and Taebu island is at the origin of the Sihwa salt lake which led to important ecological consequences on fauna and flora. In particular, the production of bivalve molluscs is important for Korean economy. The installation of a tide power plant could significantly contribute to the reduction of the lake pollution due to the increase of water exchanges between the lake and the sea. (J.S.)

Molluscs as evidence for a late Pleistocene and early Holocene humid period in the southern coastal desert of Peru (14.5°S)

Science.gov (United States)

Mächtle, Bertil; Unkel, Ingmar; Eitel, Bernhard; Kromer, Bernd; Schiegl, Solveig

2010-01-01

The southern Peruvian coastal desert around Palpa, southern Peru (14.5°S) is currently characterized by hyper-arid conditions. However, the presence of two species of molluscs ( Scutalus, Pupoides) and desert-loess deposits indicates the past development of semi-desert and grassland ecosystems caused by a displacement of the eastern desert margin due to hydrological changes. Radiocarbon dating shows that the transition to a semi-arid climate in the southern Peruvian coastal desert took place during the Greenland interstadial 1, ˜ 13.5 cal ka BP. At the beginning of the Holocene, the mollusc fauna vanished due to increasing humidity and the development of grasslands. Dust particles were fixed by the grasses, as indicated by abundant Poaceae phytoliths, and desert loess was formed. The humid period we observe here is out of phase with the palaeoenvironmental records from the Titicaca region, which indicates dry conditions at that time. This paper offers a new idea for this contradiction: an orbitally driven meridional shift of the Bolivian high might have altered the moisture supply across the Andes.

Biochemical and volatile organic compound profile of European flat oyster (Ostrea edulis) and Pacific cupped oyster (Crassostrea gigas) cultivated in the Eastern Scheldt and Lake Grevelingen, the Netherlands

NARCIS (Netherlands)

Houcke, van Jasper; Medina, Isabel; Linssen, Jozef; Luten, Joop

2016-01-01

The aim of this study was to evaluate the effect of two important different geographical cultivation areas in the Netherlands (Eastern Scheldt and Lake Grevelingen) on the volatile organic compound (VOC) profile of European flat oyster (Ostrea edulis) and Pacific cupped oyster (Crassostrea

Influence of eutrophication on metal bioaccumulation and oral bioavailability in oysters, Crassostrea angulata.

Science.gov (United States)

Li, Shun-Xing; Chen, Li-Hui; Zheng, Feng-Ying; Huang, Xu-Guang

2014-07-23

Oysters (Crassostrea angulata) are often exposed to eutrophication. However, how these exposures influence metal bioaccumulation and oral bioavailability (OBA) in oysters is unknown. After a four month field experimental cultivation, bioaccumulation factors (BAF) of metals (Fe, Cu, As, Cd, and Pb) from seawater to oysters and metal oral bioavailability in oysters by bionic gastrointestinal tract were determined. A positive effect of macronutrient (nitrate N and total P) concentration in seawater on BAF of Cd in oysters was observed, but such an effect was not significant for Fe, Cu, Pb, and As. Only OBA of As was significantly positively correlated to N and P contents. For Fe, OBA was negatively correlated with N. The regular variation of the OBA of Fe and As may be due to the effect of eutrophication on the synthesis of metal granules and heat-stable protein in oysters, respectively.

Mitogenomics does not resolve deep molluscan relationships (yet?).

Science.gov (United States)

Stöger, I; Schrödl, M

2013-11-01

The origin of molluscs among lophotrochozoan metazoans is unresolved and interclass relationships are contradictory between morphology-based, multi-locus, and recent phylogenomic analyses. Within the "Deep Metazoan Phylogeny" framework, all available molluscan mitochondrial genomes were compiled, covering 6 of 8 classes. Genomes were reannotated, and 13 protein coding genes (PCGs) were analyzed in various taxon settings, under multiple masking and coding regimes. Maximum Likelihood based methods were used for phylogenetic reconstructions. In all cases, molluscs result mixed up with lophotrochozoan outgroups, and most molluscan classes with more than single representatives available are non-monophyletic. We discuss systematic errors such as long branch attraction to cause aberrant, basal positions of fast evolving ingroups such as scaphopods, patellogastropods and, in particular, the gastropod subgroup Heterobranchia. Mitochondrial sequences analyzed either as amino acids or nucleotides may perform well in some (Cephalopoda) but not in other palaeozoic molluscan groups; they are not suitable to reconstruct deep (Cambrian) molluscan evolution. Supposedly "rare" mitochondrial genome level features have long been promoted as phylogenetically informative. In our newly annotated data set, features such as genome size, transcription on one or both strands, and certain coupled pairs of PCGs show a homoplastic, but obviously non-random distribution. Apparently congruent (but not unambiguous) signal for non-trivial subclades, e.g. for a clade composed of pteriomorph and heterodont bivalves, needs confirmation from a more comprehensive bivalve sampling. We found that larger clusters not only of PCGs but also of rRNAs and even tRNAs can bear local phylogenetic signal; adding trnG-trnE to the end of the ancestral cluster trnM-trnC-trnY-trnW-trnQ might be synapomorphic for Mollusca. Mitochondrial gene arrangement and other genome level features explored and reviewed herein thus

Respiration of bivalves from three different deep-sea areas: Cold seeps, hydrothermal vents and organic carbon-rich sediments

Science.gov (United States)

Khripounoff, A.; Caprais, J. C.; Decker, C.; Le Bruchec, J.; Noel, P.; Husson, B.

2017-08-01

We studied bivalves (vesicomyids and mytilids) inhabiting four different areas of high sulfide and methane production: (1) in the Gulf of Guinea, two pockmarks (650 m and 3150 m depth) and one site rich in organic sediments in the deepest zone (4950 m average depth), (2) at the Azores Triple Junction on the Mid-Atlantic Ridge, one hydrothermal site (Lucky Strike vent field, 1700 m depth). Two types of Calmar benthic chambers were deployed, either directly set into the sediment (standard Calmar chamber) or fitted with a tank to isolate organisms from the sediment (modified Calmar chamber), to assess gas and solute exchanges in relation to bivalve bed metabolism. Fluxes of oxygen, total carbon dioxide, ammonium and methane were measured. At the site with organic-rich sediments, oxygen consumption by clams measured in situ with the standard benthic chamber was variable (1.3-6.7 mmol m-2 h-1) as was total carbon dioxide production (1-9.6 mmol m-2 h-1). The observed gas and solute fluxes were attributed primarily to bivalve respiration (vesicomyids or mytilids), but microbial and geochemical processes in the sediment may be also responsible for some of variations in the deepest stations. The respiration rate of isolated vesicomyids (16.1-0.25.7 μmol g-1 dry weight h-1) was always lower than that of mytilids (33 μmol g-1 dry weight h-1). This difference was attributed to the presence of a commensal scaleworm in the mytilids. The respiratory coefficient (QR) ≥1 indicated high levels of anaerobic metabolism. The O:N index ranged from 5 to 25, confirming that vesicomyids and mytilids, living in symbiosis with bacteria, have a protein-based food diet.

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...... 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...

PAH assessment in the main Brazilian offshore oil and gas production area using semi-permeable membrane devices (SPMD) and transplanted bivalves

Science.gov (United States)

André Lourenço, Rafael; Francisco de Oliveira, Fábio; Haddad Nudi, Adriana; Rebello Wagener, Ângela de Luca; Guadalupe Meniconi, Maria de Fátima; Francioni, Eleine

2015-06-01

The Campos Basin is Brazil's main oil and gas production area. In 2013, more than 50 million cubic meters of produced water (PW) was discharged into these offshore waters. Despite the large volumes of PW that are discharged in the Campos Basin each day, the ecological concern of the chemicals in the PW are not completely understood. Polycyclic aromatic hydrocarbons (PAH) are the most important contributors to the ecological hazards that are posed by discharged PW. This study aimed to evaluate the potential bioaccumulation of PAH using transplanted bivalves (Nodipecten nodosus) and semi-permeable membrane devices (SPMD). The study was conducted in two platforms that discharge PW (P19 and P40). Another platform that does not discharge PW (P25) was investigated for comparison with the obtained results. Time-integrated hydrocarbon concentrations using SPMD and transplanted bivalves were estimated from the seawater near the three platforms. The bioaccumulation of the PAH in the transplanted bivalves at platforms P19 and P40 were up to fivefold greater than the bioaccumulation of the PAH at platform P25. The lowest PAH concentrations were estimated for platform P25 (4.3-6.2 ng L-1), and the highest PAH concentrations were estimated for platform P19 (9.2-37.3 ng L-1). Both techniques were effective for determining the bioavailability of the PAH and for providing time-integrated hydrocarbon concentrations regarding oil and gas production activities.

CASA in invertebrates.

Science.gov (United States)

van der Horst, Gerhard; Bennett, Monique; Bishop, John D D

2018-04-09

Sperm movement has been described in several phyla of invertebrates. Yet, sperm motility has only been quantified using computer-aided sperm analysis (CASA-Mot) in externally fertilising species (broadcast spawners) of two phyla, molluscs and echinoderms. In the present study we quantified in detail the nature of the sperm tracks, percentage motility groupings and detailed kinematics of rapid-, medium- and slow-swimming spermatozoa in the oyster Crassostrea gigas and four species never previously studied by CASA-Mot, namely the molluscs Choromytilus meridionalis, Donax serra and Haliotis midae and the echinoderm Parechinus angulosus. A feature common to all these species are the helical tracks, the diameter of which seems to be species specific. Using CASA-Mot, the behaviour of spermatozoa was also studied over time and in the presence of egg water and Ca2+ modulators such as caffeine and procaine hydrochloride. For the first time, we show that hyperactivation can be induced in all species in the presence of egg water (sea water that was mixed with mature eggs and then centrifuged) and/or caffeine, and these hyperactivated sperm tracks were characterised using CASA-Mot. We relate the different patterns of sperm motility and behaviour to reproductive strategies such as broadcast spawning and spermcasting, and briefly review studies using CASA-Mot on other invertebrates.

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

Energy Technology Data Exchange (ETDEWEB)

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

2009-07-01

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

Bioaccumulation of selected metals in bivalves (Unionidae) and Phragmites australis inhabiting a municipal water reservoir

OpenAIRE

Rzymski, Piotr; Niedzielski, Przemysław; Klimaszyk, Piotr; Poniedziałek, Barbara

2014-01-01

Urbanization can considerably affect water reservoirs by, inter alia, input, and accumulation of contaminants including metals. Located in the course of River Cybina, Maltański Reservoir (Western Poland) is an artificial shallow water body built for recreation and sport purposes which undergoes restoration treatment (drainage) every 4 years. In the present study, we demonstrate an accumulation of nine metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn) in water, sediment, three bivalve species (Anodo...

Mollusc succession of a prehistoric settlement area during the Holocene: A case study of the České středohoří Mountains (Czech Republic)

Czech Academy of Sciences Publication Activity Database

Juřičková, L.; Horáčková, J.; Jansová, A.; Ložek, Vojen

2013-01-01

Roč. 23, č. 12 (2013), s. 1811-1823 ISSN 0959-6836 Institutional support: RVO:67985831 Keywords : České středohoří Mountains * Holocene * mollusc succession * prehistoric settlement * radiocarbon AMS dating Subject RIV: DB - Geology ; Mineralogy Impact factor: 3.794, year: 2013

Heavy metal concentrations in some oyster species of the Caribbean coast of Columbia. Zur Belastung einiger Muschelarten von der karibischen Kueste Kolumbiens mit Schwermetallen

Energy Technology Data Exchange (ETDEWEB)

Campos, N.H.

1984-01-01

Heavy metal concentrations (Cd, Cu, Pb) were measured in oysters (Crassostrea rhizophorae) and two species of tree oysters (Isognomon alatus and I. bicolor) at various points of the Caribbean coast of Columbia. Samples were taken at 4 different times of the year. Cd and Cu concentrations were highest in oysters; Pb concentrations did not differ between the species. The annual curve was similar for all heavy metals, with maximum concentrations in the dry season. In the area investigated, the WHO limiting values for daily Cd intake with oysters may be exceeded at times in most places, while the daily lead intake was found to be below the WHO limiting values. A comparison with other regions of the world shows that Cd and Pb concentrations in molluscs are high at the Caribbean coast.

Yessotoxin detection in bivalve molluscs: A case study from coastal mussel farms (Sardinia, Italy

Directory of Open Access Journals (Sweden)

Alessandro Graziano Mudadu

2018-02-01

Full Text Available This work reports the first communication relating to the presence of yessotoxins in Mytilus galloprovincialis from coastal mussel farms (Sardinia, western Mediterranean detected during 2008 and 2013 through a monitoring programme. The paper emphasizes how the changes both in yessotoxin permitted limits and used methods, established by legislation, have influenced the interpretation of the obtained results. Consequently, the samples that resulted negative during 2008 would have been positive until August 2013 and negative from September 2013 up to now, and the samples that were positive in 2013 would have been positive in 2008 and negative nowadays, according to Regulation currently in force. Regular monitoring of biotoxins demonstrated that, although yessotoxins have been rarely present in the past in Sardinia, they may cause toxicity in shellfish. So, it’s important to keep up on legislation’s changing and laboratory methods.