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1.
Ecotoxicol Environ Saf ; 203: 110994, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888603

RESUMO

The effects of cyanobacteria (Aphanizomenon flos-aquae (90%), Microcystis aeruginosa) and dense Elodea canadensis beds on the health endpoints of the amphipod Gmelinoides fasciatus and bivalve mollusc Unio pictorum were examined in mesocosms with simulated summer conditions (July-August 2018) in the environment of the Rybinsk Reservoir (Volga River Basin, Russia). Four treatments were conducted, including one control and three treatments with influencing factors, cyanobacteria and dense elodea beds (separately and combined). After 20 days of exposure, we evaluated the frequency of malformed and dead embryos in amphipods, heart rate (HR) and its recovery (HRR) after stress tests in molluscs as well as heat tolerance (critical thermal maximum or CTMax) in both amphipods and molluscs. The significant effect, such as elevated number of malformed embryos, was recorded after exposure with cyanobacteria (separately and combined with elodea) and presence of microcystins (MC) in water (0.17 µg/l, 40% of the most toxic MC-LR contribution). This study provided evidence that an elevated number (>5% of the total number per female) of malformed embryos in amphipods showed noticeable toxicity effects in the presence of cyanobacteria. The decreased oxygen under the influence of dense elodea beds led to a decrease in HR (and an increase in HRR) in molluscs. The notable effects on all studied biomarkers, embryo malformation frequency and heat tolerance in the amphipod G. fasciatus, as well as the heat tolerance and heart rate in the mollusc U. pictorum, were found when both factors (elodea and cyanobacteria) were combined. The applied endpoints could be further developed for environmental monitoring, but the obtained results support the importance of the combined use of several biomarkers and species, especially in the case of multi-factor environmental stress.


Assuntos
Anfípodes/efeitos dos fármacos , Bivalves/efeitos dos fármacos , Cianobactérias/metabolismo , Monitoramento Ambiental/métodos , Hydrocharitaceae/metabolismo , Poluentes Químicos da Água/toxicidade , Anfípodes/metabolismo , Animais , Aphanizomenon/metabolismo , Biomarcadores/análise , Bivalves/metabolismo , Embrião não Mamífero/efeitos dos fármacos , Embrião não Mamífero/metabolismo , Frequência Cardíaca/efeitos dos fármacos , Microcistinas/metabolismo , Microcistinas/toxicidade , Microcystis/metabolismo , Federação Russa , Poluentes Químicos da Água/metabolismo
2.
Sci Total Environ ; 743: 140754, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32758840

RESUMO

Harmful algal blooms (HABs) and thermal stress as climate changes become more common in global water ecosystem, especially under eutrophic habitats. Here our study examined the combined impacts of bloom forming cyanobacteria Microcystis aeruginosa and thermal stress on the antioxidant responses of the ecologically important species triangle sail mussel Hyriopsis cumingii. The differential responses of a series of enzymes, e.g. superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST), as well as signal metabolites including reactive oxygen species (ROS), malondialdehyde (MDA) and glutathione (GSH) involved in antioxidant defense mechanisms were analyzed during 14 d exposure to toxic cyanobacterium M. aeruginosa and 7 d depuration period. The activities of SOD and GPx as well as the content of ROS and MDA in H. cumingii increased, while CAT activity reduced due to M. aeruginosa exposure. Thermal stress resulted in decrease of CAT, the accumulation of GSH and the enhance of GST and SOD. Meanwhile, the interactive effects among M. aeruginosa, thermal stress and time were also observed on most parameters except for GST activity. The total amount of microcystins (MC) in sail mussels increased with concentrations of exposed M. aeruginosa, independently of the presence or absence of thermal stress. Although around 50% of MC in mussels dropped in the depuration period, most parameters showed alterations because of cyanobacteria exposure and thermal stress. Overall, these findings suggested that toxic cyanobacteria or thermal stress induces oxidative stress and severely affects the enzymes activities and intermediates level associated with antioxidant defense mechanisms in sail mussels respectively. More importantly, the toxic impacts on sail mussels could be intensified by their combination.


Assuntos
Bivalves , Microcystis , Unionidae , Animais , Antioxidantes , Catalase , Ecossistema , Microcistinas , Estresse Oxidativo , Superóxido Dismutase
3.
Nat Commun ; 11(1): 3895, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32753588

RESUMO

The mussel byssus has long been a source of inspiration for the adhesion community. Recently, adhesive synergy between flanking lysine (Lys, K) and 3,4-Dihydroxyphenylalanine (DOPA, Y) residues in the mussel foot proteins (Mfps) has been highlighted. However, the complex topological relationship of DOPA and Lys as well as the interfacial adhesive roles of other amino acids have been understudied. Herein, we study adhesion of Lys and DOPA-containing peptides to organic and inorganic substrates using single-molecule force spectroscopy (SMFS). We show that a modest increase in peptide length, from KY to (KY)3, increases adhesion strength to TiO2. Surprisingly, further increase in peptide length offers no additional benefit. Additionally, comparison of adhesion of dipeptides containing Lys and either DOPA (KY) or phenylalanine (KF) shows that DOPA is stronger and more versatile. We furthermore demonstrate that incorporating a nonadhesive spacer between (KY) repeats can mimic the hidden length in the Mfp and act as an effective strategy to dissipate energy.


Assuntos
Adesivos/química , Di-Hidroxifenilalanina/química , Lisina/química , Sequência de Aminoácidos , Animais , Bivalves , Dipeptídeos , Peptídeos/síntese química , Propriedades de Superfície , Titânio/química
4.
Environ Monit Assess ; 192(9): 581, 2020 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-32789571

RESUMO

Noble pen shell (Pinna nobilis) is an endemic species and the largest known bivalve in the Mediterranean Sea. By filtering large amounts of water, they maintain a high percentage of organic matter, hence playing an important role in the marine ecosystem. The ecological community of pen shells is impressive, and there are numerous microorganisms present in its soft tissues. Since this species is highly endangered due to recently described mass mortalities throughout the Mediterranean, this study was aimed at finding out more about its microbiome. In this study, we identified the predominant bacterial populations of specimens collected at three separate locations along the Eastern Adriatic coast. The predominant bacteria were isolated and 16S rRNA sequencing was performed to identify eight different bacterial genera: Aestuariibacter sp., Aliivibrio sp., Alteromonas sp., Marinobacter sp., Pseudoalteromonas sp., Rubritalea sp., Thalassospira sp. and the Vibrio splendidus clade. The identified genera are ubiquitous in the marine environment and have previously been described as both beneficial symbionts and potential pathogens in other molluscs. There was a clear difference in the predominant bacterial populations between northern and southern sampling sites, which could be linked to water temperature. These findings indicate the need for expanded sampling over a longer time period, since more exhaustive research would provide information vital to the conservation of this critically endangered species.


Assuntos
Bivalves , Ecossistema , Animais , Bactérias , Monitoramento Ambiental , Mar Mediterrâneo , Filogenia , RNA Ribossômico 16S , Vibrio
5.
Environ Pollut ; 265(Pt A): 115115, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32806413

RESUMO

Though invertebrates are one of the largest groups of animal species in the sea and exhibit robust immune and neural responses that are crucial for their health and survival, the potential immunotoxicity and neurotoxicity of the most produced chemical bisphenol A (BPA), especially in conjunction with microplastics (MPs), still remain poorly understood in marine invertebrate species. Therefore, the impacts of exposure to BPA and MPs alone or in combination on a series of immune and neural biomarkers were investigated in the invertebrate bivalve species blood clam (Tegillarca granosa). Evident immunotoxicity as indicated by alterations in hematic indexes was observed after two weeks of exposure to BPA and MPs at environmentally realistic concentrations. The expression of four immune-related genes from the NFκB signaling pathway was also found to be significantly suppressed by the BPA and MP treatment. In addition, exposure to BPA and MPs led to an increase in the in vivo contents of three key neurotransmitters (GABA, DA, and ACh) but a decrease in the expression of genes encoding modulatory enzymes and receptors for these neurotransmitters, implying the evident neurotoxicity of BPA and MPs to blood clam. Furthermore, the results demonstrated that the toxic impacts exerted by BPA were significantly aggravated by the co-presence of MPs, which may be due to interactions between BPA and MPs as well as those between MPs and clam individuals.


Assuntos
Bivalves , Poluentes Químicos da Água , Animais , Compostos Benzidrílicos , Microplásticos , Fenóis , Plásticos
6.
Environ Monit Assess ; 192(9): 566, 2020 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-32767125

RESUMO

A large number of white hard clam farms are in the estuary shoreline of Saigon-Dongnai Rivers, which flow through Ho Chi Minh City, a megacity, and numerous industrial zones in the basin catchment area. In this study, eleven trace elements (Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Hg, and Pb) in the hard clam Meretrix lyrata and its habitats including surface water, suspended particulate matter, and sediment were evaluated to understand the bioaccumulation of trace metals from the environment into the whole tissues of the hard clam as well as its different organs. The samples were collected monthly in dry, transition, and wet seasons of the southern part of Vietnam from March to September 2016. The results showed that seasonal and spatial variations of the studied metal concentrations in the hard clam M. lyrata might be influenced by the sea current as well as the surface runoff in the rainy season. The relationship between condition index and the element concentrations in M. lyrata might be affected by the living environment conditions and farming methods. In addition, the hazard index values of all trace elements in the hard clam M. lyrata harvested in the sampling time show that the hard clams farmed in the study area were safe for local consumers.


Assuntos
Bivalves , Metais Pesados/análise , Oligoelementos/análise , Poluentes Químicos da Água/análise , Animais , Bioacumulação , Cidades , Monitoramento Ambiental , Estuários , Sedimentos Geológicos , Vietnã
7.
Mar Pollut Bull ; 158: 111391, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32753177

RESUMO

Sewage is among the largest components of coastal pollution, showing a variable scale and size when causing an impact. In this study, temporal and spatial sewage-related gradients were identified using univariate and multivariate methods. Phosphates and nitrogen-based nutrients, except nitrate, were associated to sewage. Abundance and species richness decrease with distance from the sewage outfall while evenness increased. Filter-feeder bivalves and grazer crustaceans showed preference for the sewage discharge site. Gastropods were more abundant at an intermediate distance, likely reflecting primary production enhancement by sewage. Beta diversity was lower at the location and time with highest sewage loadings. The turnover component of beta diversity expressed as an absolute or proportional value was also useful to detect temporal and spatial sewage-related gradients. Highly energetic hydrodynamics contributes to ameliorate sewage impacts, yet not enough to veil the effect of pollution in this study.


Assuntos
Bivalves , Esgotos/análise , Animais , Ecossistema , Monitoramento Ambiental
8.
Mar Pollut Bull ; 158: 111401, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32753186

RESUMO

This work aimed to investigate effects of the ocean contamination by the sunscreen Benzophenone-3 (BP3) and acidification, caused by CO2 enrichment, to the yellow clam, Amarilladesma mactroides. Biochemical biomarkers were analyzed in tissues (gills, digestive gland, and mantle) of clams exposed to the environmental concentration of 1 µg/L BP3, at seawater natural pH (pH 8.1) and at lower pH (pH 7.6). The tissues responded in different ways considering their physiological roles. In general, BP3 altered activity of the enzymes, glutathione-S-transferase (GST) and glutathione cysteine ligase (GCL); but mostly increased the level of glutathione (GSH). These effects were enhanced by acidification, without augmenting lipid peroxidation (LPO). Carbonic anhydrase activity (CA) increased after BP3 exposure in the digestive gland and decreased in the gills at pH 7.6, while Ca2+-ATPase activity was affected by acidification only. Changing levels of these enzymes can alter shell formation and affect the bivalve maintenance in impacted environments.


Assuntos
Bivalves , Poluentes Químicos da Água , Animais , Benzofenonas , Biomarcadores , Brânquias , Concentração de Íons de Hidrogênio , Peroxidação de Lipídeos
9.
Mar Pollut Bull ; 158: 111415, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32753199

RESUMO

The mangrove sediment cores from middle and upper Zuari Estuary were studied for grain size, organic carbon, total and bioavailable metals (Fe, Mn, Zn, Pb) to evaluate the metal enrichment and pollution, along with the bioaccumulation of metals by edible bivalve Polymesoda erosa to understand the toxicity of metals. The distribution of metals varied between middle and upper estuary and was attributed to difference in metal source, hydrodynamics and/or post-depositional behavior. The pollution indices viz., contamination factor and pollution load index revealed metal pollution at both middle and upper estuary. Speciation of Mn, Zn and Pb indicated their bioavailability in sediments, and the application of screening quick reference table and risk assessment code suggested possible harmful effects of Mn on biota. The concentration of metals in Polymesoda erosa was more than the standard permissible limit, at both middle and upper estuary indicating metal toxicity to Polymesoda erosa and human health.


Assuntos
Bivalves , Metais Pesados/análise , Poluentes Químicos da Água/análise , Animais , Bioacumulação , Monitoramento Ambiental , Estuários , Sedimentos Geológicos , Índia , Metais/análise
10.
Environ Monit Assess ; 192(8): 553, 2020 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-32737592

RESUMO

The activity concentrations of natural radionuclides (210Po and 210Pb) and residual pesticide levels were determined from the fish (red mullet, common sole, anchovy, horse mackerel, gray mullet, and sardine) and mussel samples collected in Izmir Bay seasonally from October 2012 and July 2013. The 210Po and 210Pb concentrations varied between 5.7 ± 4.0 Bq kg-1 dry weight (dw) to 353.7 ± 45.0 Bq kg-1(dw) and 0.7 ± 0.2 Bq kg-1 (dw) to 4.3 ± 0.8 Bq kg-1 (dw), respectively. From a public health point of view, the fish and mussel collected from the Izmir Bay are not harmful to consumers.


Assuntos
Bivalves , Praguicidas , Polônio/análise , Poluentes Radioativos da Água/análise , Animais , Monitoramento Ambiental , Chumbo , Radioisótopos de Chumbo/análise , Medição de Risco , Turquia
11.
Gene ; 757: 144925, 2020 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-32622991

RESUMO

Porphyrins, one of the most common shell pigments, are by-products of the haem pathway. 5-Aminolaevulinate synthase (ALAS) is the first and rate-limiting enzyme in this pathway and has been well studied in vertebrate species. However, the function of ALAS in shell colouration has been poorly studied in molluscs, which are renowned for their colourful shells. In the present study, an ALAS gene, named PyALAS, was identified through whole-genome scanning in the Yesso scallop (Patinopecten yessoensis), an economically and evolutionarily important bivalve species in which the shell colour represents polymorphism. Two conserved domains were detected in the PyALAS protein sequence, including a Preseq-ALAS domain and a 5-ALAS domain, confirming the identification of PyALAS. Phylogenetic analysis of the ALAS proteins among various invertebrate and vertebrate species revealed a high consistency between the molecular evolution of ALAS and the species taxonomy. PyALAS was ubiquitously expressed in most adult tissues of the Yesso scallop. The left mantle expressed a significantly higher level of PyALAS than the right side in brown scallops, whereas there was no significant difference in white scallops. Significantly different expression levels of PyALAS was also detected between the two different shell colour strains. These data indicate that PyALAS plays an important role in shell colouration in Yesso scallops and the present study provides new insights into the molecular mechanism of shell colouration in molluscs.


Assuntos
5-Aminolevulinato Sintetase/genética , Bivalves/genética , Pigmentação , 5-Aminolevulinato Sintetase/metabolismo , Exoesqueleto/metabolismo , Animais , Bivalves/classificação , Bivalves/metabolismo
12.
Proc Biol Sci ; 287(1931): 20200970, 2020 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-32673558

RESUMO

Ocean warming impacts the fitness of marine ectothermic species, leading to poleward range shifts, re-shuffling of communities, and changes in ecosystem services. While the detrimental effects of summer heat waves have been widely studied, little is known about the impacts of winter warming on marine species in temperate regions. Many species benefit from low winter temperature-induced reductions in metabolism, as these permit conservation of energy reserves that are needed to support reproduction in spring. Here, we used a unique outdoor mesocosm system to expose a coastal predator-prey system, the sea star Asterias and the blue mussel Mytilus, to different winter warming scenarios under near-natural conditions. We found that the body condition of mussels decreased in a linear fashion with increasing temperature. Sea star growth also decreased with increasing temperature, which was a function of unaltered predation rates and decreased mussel body condition. Asterias relative digestive gland mass strongly declined over the studied temperature interval (ca twofold). This could have severe implications for reproductive capacity in the following spring, as digestive glands provide reserve compounds to maturing gonads. Thus, both predator and prey suffered from a mismatch of energy acquisition versus consumption in warmer winter scenarios, with pronounced consequences for food web energy transfer in future oceans.


Assuntos
Bivalves/fisiologia , Mudança Climática , Comportamento Predatório/fisiologia , Água do Mar/química , Estrelas-do-Mar/fisiologia , Animais , Ecossistema , Cadeia Alimentar , Oceanos e Mares , Estações do Ano , Inanição , Temperatura
13.
Environ Pollut ; 266(Pt 1): 115219, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32683232

RESUMO

Microplastics (MPs) in the marine environment are ubiquitous. The ingestion of these pollutants by marine organisms has drawn global attention. This work studies the distribution pattern and characteristics of MPs found in the body of the clam Donax cuneatus and its environment in order to understand the possible relationship between the MP concentration in the environment (water and sediment) and that in the clam's body. Samples of D. cuneatus were collected from the coast between Vembar and Periyathazhai in Tuticorin district along GoM. MP concentrations range from 0.6 to 1.3 items/g (wet weight) in clams, 10-30 items/l in water, and 24-235 items/kg in sediment. Small-sized clams contain the highest concentration of MPs. Hence it is hypothesised that allometric relationship exists between body size and MP concentration, depending on the surface-area to volume ratio. MP abundance in clam body has a clear, positive, significant correlation with MP abundance in sediment but not with abundance of MP in water. Microplastics of fiber type with size 100-250 µm have a predominant presence in clams. The study identified ten types of polymers, of which polyethylene is the most common polymer in all sample types. FTIR-ATR spectra and surface morphology indicate that most of the microplastics have been strongly weathered. Energy dispersive X-ray spectroscopy analysis detected heavy metals associated with MPs like Cd, Pb, Cu, Zn, Ni and Fe. Filter-feeding clams like Donax sp. can provide valuable information on the spatial patterns of MP distribution, and so can act as bio-indicators in monitoring MP pollution in coastal areas.


Assuntos
Bivalves , Poluentes Químicos da Água/análise , Animais , Ecossistema , Monitoramento Ambiental , Índia , Microplásticos , Plásticos
14.
An Acad Bras Cienc ; 92 Suppl 1: e20190169, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32638864

RESUMO

Abstract: This study assessed the effect of salinity on embryonic development, larval growth and survival of the yellow clam Mesodesma mactroides in laboratory. Embryos and larvae of M. mactroides were submitted and maintained at four different salinities: 20, 25, 30 and 35 ppt, to determine optimal conditions for the species. Through descriptive analysis, the results showed that the embryos tolerate salinities between 25 - 35 ppt, presenting fast metamorphoses at salinities 30 and 35 ppt, during experimental period of 27 hours. The same tolerance pattern was observed in larval stage (25 - 35 ppt), showing a better development in salinity of 35 ppt. This result is verified in biometric analyzes of height and length of the shells and survival rate, with higher averages in treatments with salinity 35 ppt. The experimental period of this stage lasted 27 days, when the larvae were able to settle. These results indicate that embryos and larvae of M. mactroides tolerate salinities between (25-35 ppt), with the best growth and survival on high salinities being recommended to better yields in laboratory.


Assuntos
Bivalves , Salinidade , Animais , Desenvolvimento Embrionário , Larva
15.
Sci Total Environ ; 742: 140427, 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-32721715

RESUMO

Overwinter mortality of the Manila clam (Ruditapes philippinarum) is a major impediment to the aquaculture industry in China. Cold tolerance ability has a tremendous impact on the survivability of R. philippinarum during the overwintering season. In this study, we evaluated the effects of acute and chronic cold stress on the expression of Cold Shock Domain-containing E1 (CSDE1) and Antifreeze protein type II (AFPII) genes and the activities of lysozyme (LZM), catalase (CAT), and superoxide dismutase (SOD) in three cultivated strains (zebra, white, and white zebra) and two wild populations (northern and southern) of R. philippinarum. Under acute and chronic cold stress, the expression levels of CSDE1 and AFPII mRNA in the gills and hepatopancreas were significantly increased in all populations, but the increase varied among different strains and populations. Under acute cold stress, SOD activity significantly decreased in the two wild populations and the white zebra strain. LZM activity significantly decreased but CAT activity significantly increased in selected strains and populations after acute low temperature stress (P < 0.05). Under chronic cold stress, SOD activity significantly increased in the northern population and white zebra strain, while CAT activity significantly increased in the southern population and the white and zebra strains. These results provide useful information about the Manila clam response to cold stress that may be applied to improve the low temperature resistance of Manila clams in aquaculture environments.


Assuntos
Bivalves , Aclimatação , Animais , China , Brânquias , Hepatopâncreas
16.
Sci Total Environ ; 742: 140661, 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-32721753

RESUMO

Increasing selenium (Se) levels in aquatic environments raise concerns all over the world. This study investigated effects of organic amendments (cattail and reed litter) and porous media (gravels and clam shells) on Se removal efficiency of horizontal subsurface flow constructed wetlands. Our results show clam shells reduced Se (by mass) up to 2.4-fold faster than gravels within 19 days. Using clam shells as the sole substrate, 96.3% removal efficiency was obtained for cattail litter as an amendment, compared to 88.7% for reed litter over 10 days, although the latter released carbon and nitrogen at least 1.4-fold faster than the former. Meanwhile, speciation analysis suggests Se0 (~75%) and organo-Se (~94%) dominated the biofilms on shells and plant litter, respectively, as substrates. Overall, this study suggests clam shells and cattail litter as an effective medium and carbon source, respectively, can enhance microbial Se removal without posing risks to wildlife health.


Assuntos
Bivalves , Selênio , Typhaceae , Animais , Carbono , Nitrogênio , Áreas Alagadas
17.
Sci Total Environ ; 741: 140483, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32615439

RESUMO

It is well recognized that filter media play a crucial role in constructed wetlands (CWs) for decontamination of phosphorus (P)-rich wastewater. This study investigates the suitability of raw white hard clam shells (WHC) and white hard clam shells thermally modified at 800 °C (WHC-M800) as potential media to enhance P treatment performance in CWs. The results indicated that both WHC and WHC-M800 displayed appropriate physicochemical properties, such as high porosity, excellent hydraulic conductivity, and rich Ca content. WHC-M800 exhibited a superior P adsorption capacity (38.7 mg/g) to WHC (12.8 mg/g). However, the practical utilization of WHC-M800 as filter media in CWs may be compromised, due to certain limitations, for example: extremely high pH values in the post-adsorption solutions; high weight losses during calcination and adsorption processes; low mechanical strength; and intensive energy consumption. In contrast, the WHC demonstrated significant advantages of reasonably high P adsorption capacity, locally abundant availability, low cost, and marginal side effects. The fractionation of inorganic P of WHC and WHC-M800 revealed that Ca-bounded P was the most dominant binding form, followed by loosely bound P, Fe-P, occluded P, and Al-P. The present study demonstrates that recycling of WHC shells as a potential substrate in CWs provides a feasible method for upgrading P removal in CWs. Additionally, it helps to reduce waste WHC shells in a simple, cheap, and eco-friendly way, thus can double environmental benefits.


Assuntos
Bivalves , Águas Residuárias , Adsorção , Animais , Fósforo , Eliminação de Resíduos Líquidos , Áreas Alagadas
18.
Mar Environ Res ; 159: 105000, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32662434

RESUMO

Coastal transitional waters are exposed to many anthropogenic threats. This study aims to assess the trace metals' pollution status of transitional waters by evaluating its biological effects in the clam Venerupis decussata. Among the studied sites along the Tunisian littoral, South Tunis and Boughrara were the most impacted, since clams from these two lagoons presented significant differences in: (i) trace metal contents, (ii) in-cell hydrogen peroxide, (iii) enzymatic and non-enzymatic defenses, (iv) damage to lipids and proteins, and (v) protein post-translational modifications. These changes related to evident histopathological traits. PCA showed a clear separation between the digestive gland and gills tissues and illustrated an impact gradient in Tunisian coastal lagoons. Water temperature was revealed as an added natural stressor that, when concurring with high pollution, may jeopardize an ecosystem's health and contribute to the accumulation of hazardous metals in organisms.


Assuntos
Bivalves , Metais , Poluentes Químicos da Água , Animais , Carga Corporal (Radioterapia) , Ecossistema , Monitoramento Ambiental , Estresse Oxidativo
19.
Mar Pollut Bull ; 157: 111282, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32658665

RESUMO

Assessing the carrying capacity of ecosystems is crucial to the selection of suitable and sustainable locations for aquaculture farms. In Malpeque Bay (PEI, Canada), the potential expansion of mussel farms has driven a series of numerical modelling studies. We coupled sub-models for sea lettuce, wild and cultured oysters and wild softshell clams to an existing ecosystem model to better understand nutrient dynamics and the carrying capacity of Malpeque Bay. Simulations suggested that competition for nutrients between phytoplankton and sea lettuce and filtration by cultured bivalves predominantly mitigate eutrophication effects. The addition of sea lettuce reduced mussel growth by 2% on average and up to 9% near eutrophic estuaries favouring macroalgae growth. Projected new mussel farms reduced current mussel growth by 2% also, suggesting that the carrying capacity of the bay may not be reached yet. Both current and projected aquaculture activities seemed to have limited effects on natural bivalve growth.


Assuntos
Bivalves , Ecossistema , Animais , Aquicultura , Canadá , Eutrofização
20.
Mar Pollut Bull ; 157: 111315, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32658680

RESUMO

Noroviruses are the most common cause of gastroenteritis outbreaks in humans and bivalve shellfish consumption is a recognized route of infection. Our aim was to detect and characterize norovirus in bivalves from a coastal city of Brazil. Nucleic acid was extracted from the bivalve's digestive tissue concentrates using magnetic beads. From March 2018 to June 2019, 77 samples were screened using quantitative RT-PCR. Noroviruses were detected in 41.5%, with the GII being the most prevalent (37.7%). The highest viral load was 3.5 × 106 and 2.5 × 105 GC/g in oysters and mussels, respectively. PMA-treatment demonstrated that a large fraction of the detected norovirus corresponded to non-infectious particles. Genetic characterization showed the circulation of the GII.2[P16] and GII.4[P4] genotypes. Norovirus detection in bivalves reflects the anthropogenic impact on marine environment and serves as an early warning for the food-borne disease outbreaks resulting from the consumption of contaminated molluscs.


Assuntos
Bivalves , Norovirus/genética , Animais , Brasil , Genótipo , Humanos , RNA Viral , Frutos do Mar
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