Saccostrea Cucullata Research Articles

Assessment of heavy metal and petroleum hydrocarbon contamination in the Sultanate of Oman with emphasis on harbours, marinas, terminals and ports

The assessment here includes data on levels of contaminants (petroleum hydrocarbons and heavy metals) in sediments and biomonitor organisms, including the eulittoral rock oyster Saccostrea cucullata and subtidal biomonitors, the barnacle Balanus trigonus and the antipatharian coral Antipathes sp., at harbours, marinas, terminals and large ports along the coastline of Oman. TBT levels in harbour and port sediments up to a maximum of 100ppb TBT dry weight are highlighted. Oysters contained concentrations up to 367ppm mg TPH/kg dry weight. The maximum levels of Cd, Cu, Pb and Zn were found in the subtidal sediments and barnacles at the oil tanker loading Single Buoy Mooring stations in Mina Al Fahal. In general, the levels of most of the contaminants analysed are at low to moderate concentrations compared to those in highly contaminated sites such as shipyards and dry docks, but continued monitoring is recommended especially during any dredging campaigns.

Multiple approaches to assess the safety of artisanal marine food in a tropical estuary.

In this study, metal and metalloid concentrations and pathogens were measured in shellfish at different locations in a tropical estuary, including sites impacted by sewage and industry. Oyster, mangrove snails and mud snails did not exceed Australian and New Zealand Food Standards maximum levels for copper, lead or estimated inorganic arsenic at any site although copper concentrations in oysters and mud snails exceeded generally expected levels at some locations. Bacterial community composition in shellfish was species-specific regardless of location and different to the surrounding water and sediment. In the snails Telescopium telescopium, Terebralia palustris and Nerita balteata, some bacterial taxa differed between sites, but not in Saccostrea cucullata oysters. The abundance of potential human pathogens was very low and pathogen abundance or diversity was not associated with site classification, i.e. sewage impact, industry impact and reference.

温度、盐度及交互作用对僧帽牡蛎(Saccostrea cucullata)呼吸排泄的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 温度、盐度及交互作用对僧帽牡蛎(Saccostrea cucullata)呼吸排泄的影响 DOI: 10.5846/stxb201507271570 作者: 作者单位: 宁波市海洋与渔业研究院,宁波市海洋与渔业研究院,宁波市江北区海洋与渔业局;宁波市江北区海洋与渔业局,宁波市海洋与渔业研究院,宁波大学海洋学院 作者简介: 通讯作者: 中图分类号: 基金项目: 公益性行业（农业）科研专项项目（201303047）；宁波市科技计划重大项目（2014C10018）；欧盟第六框架项目（INCO-CT-2004-510706） Effects of water temperature and salinity on oxygen consumption rate and ammonia excretion rate of Saccostrea cucullata Author: Affiliation: Ningbo Academy of Oceanology and Fishery,Ningbo,Ningbo Academy of Oceanology and Fishery,Ningbo,Jiangbei Ocean and Fishery Bureau,Ningbo,Ningbo Academy of Oceanology and Fishery,Ningbo,Ocean college of Ningbo University,Ningbo Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:采用实验生态学方法研究了温度（13、18、23、28、31、34℃）和盐度（18、23、28、33）对僧帽牡蛎（Saccostrea cucullata）耗氧率和排氨率的影响，并分析了二者交互作用对呼吸排泄的影响。结果表明，不同温度条件下，僧帽牡蛎的耗氧率变化范围为0.43-3.15mg g-1 h-1，排氨率的变化范围为72.62-1245.77μg g-1 h-1，方差分析显示，温度和盐度对僧帽牡蛎耗氧率（F=60.440，P < 0.01）和排氨率（F=61.083，P < 0.01）的影响均极显著；二者的交互作用对僧帽牡蛎耗氧率（F=4.907，P < 0.01）和排氨率（F=11.412，P < 0.01）影响也极显著，耗氧率（Y）、排氨率（Y）与温度（T）和盐度（S）之间的二元线性回归方程为Y=a+bT+cS+dT×S。在一定温度范围内（13-31℃），僧帽牡蛎单位体重耗氧率（Y）与温度（T）呈正相关，符合指数方程Y=aebT，其中a的取值范围为0.1378-0.2117，b的取值范围为0.0757-0.0912；单位体重排氨率也与温度呈正相关，符合上述指数方程，其中a的取值范围为20.364-30.634，b的取值范围为0.1004-0.1341。不同温度和盐度条件下，僧帽牡蛎呼吸排泄的氧氮比在2.20-7.78之间，平均值为3.81。 Abstract:Intertidal oyster (Saccostrea cucullata) is an important cultivated species and macro-fouling organism in the southeastern China Sea, and it is an important model organism for studies on shellfish physiology and marine ecology. Oxygen consumption rate and ammonia excretion rate are important parameters of shellfish physiology and metabolism, and can be measured as sensitive indicators of pollutant toxicity. However, little is known about the effects of environmental factors affect oxygen consumption rate and ammonia excretion rate of Saccostrea cucullata. The effects of water temperature (13, 18, 23, 28, 31, 34℃) and salinity (18, 23, 28, and 33) on oxygen consumption rate and ammonia excretion rate in Saccostrea cucullata were analyzed using experimental ecological methods. Oxygen consumption rate varied from 0.43 mg g-1 h-1 to 3.15 mg g-1 h-1 and the ammonia excretion rate varied from 72.62 μg g-1 h-1 to 1245.77 μg g-1 h-1 in different water temperature. Water temperature and salinity significantly affected oxygen consumption rate (F=60.440) and ammonia excretion rate (F=61.083); additionally, the combination of water temperature and salinity affected oxygen consumption rate (F=4.907) and ammonia excretion rate F=11.412). Temperature varied from 13 to 31℃ and salinity varied from 18 to 28, and the relationship between oxygen consumption or ammonia excretion rate (Y) and temperature (T) and salinity (S) can be represented by the equation Y=a+bT+cS+dT×S. The relationship between oxygen consumption rate (Y) and water temperature (T) can be described by the regression equation:Y=aebT, where a ranges from 0.1378 to 0.2117, and b ranges from 0.0757 to 0.0912. The relationship between ammonia excretion rate (Y) and water temperature (T) can also be described by the regression equation:Y=aebT, where a ranges from 20.364 to 30.634, and b ranges from 0.1044 to 0.1341. The atomic ratio of O and N varied from 2.20 to 7.78, with a mean of 3.81 to maintain standard metabolism in Saccostrea cucullata. 参考文献 相似文献 引证文献

Concentrations of Heavy Metals in Edible Dominant Oyster (Saccostreacucullata) Inhabiting Sagar Island, West Bengal

The heavy metals from the ambient environment enter the tissues of marine molluscs very frequently as they feed on the plankton of marine and estuarine water. Sagar island, situated in the northeast coast of Bay of Bengal, is the habitat of three major species of oysters namely Saccostrea cucullata, Crassostrea cuttackensis and Crassostrea madrasensis. By virtue of their sedentary nature, these species are exposed to all categories of pollutants, which have put them in the domain of indicator species. In this present paper, the concentrations of zinc, copper and lead were assessed in Saccostrea cucullata inhabiting Sagar island, Indian Sundarbans. A unique seasonal variation is observed in the accumulation of the selected heavy metals. A more detailed study is needed to establish the species as indicator of heavy metals.

Rare Earth Elements Behaviour at West Coast of Peninsular Malaysia Rocky Shore Ecosystem Using Saccostrea cucullata as Bioindicator

This study focuses on the assessment of rare earth elements (REEs) in rocky shore ecosystem along west coast region of Peninsular Malaysia coastal waters, describing their partitioning in selected body part of Saccostrea cucullata and deliberating on interspatial variability. Samples were digested using Teflon Bomb technique and concentrations of 14 naturally occurring REEs were measured using ICP-MS technique, along with selected trace metals for additional data. The REEs fractionation patterns normalized to chondrite were remarkably similar, indicating a common source of the REEs. Consistent REEs abundance patterns were found in all samples, with enrichment of LREE over HREE, which implies that REEs are transported as a coherent group through west coast of Peninsular Malaysia aquatic ecosystems. Quantification of anomalies calculated using values normalized to chondrite data presented ratios higher than unity for Ce and ratios lower than unity for Eu in all sites. Filter feeder S. cucullata is considered to be highly potential as a bioindicator for REEs, undoubtedly due to its feeding behaviour that is much related to suspended particles as REEs sources. Comparative results showed that the values are considerably below the safety limit, with the exception of Ce and Nd in the soft tissue of S. cucullata.

Malcofaunal Diversity of Chilika Lake, Odisha, India

Investigation during the period of 3 years from 2007 to 2010 on the malacofauna of Chilika lake revealed the occurrence of 126 molluscan taxa belonging to 56 families, 18 orders of three classes in the bottom sediment. Of these 61 species belonged to Bivalvia, 64 species belonged to Gastropoda and one species belonged to Polyplacophora. Maximum Bivalvia and Gastropoda taxa were found in the outer channel region of the lake. The dominating species were Crassostrea cuttackensis, Saccostrea cucullata, Brachidontes undulatus, Meretrix meretrix among bivalves and Cerethideopsilla cingulata, Bullia vittata, Nassarious stolatus, Indothias lacera, Natica tigrina, Turritella attenuata were from the gastropods. Occurrence of a large number of marine taxa is most probably associated with the opening of new lagoon during 1st August 2008.

Concentrations of Heavy Metals in Commercially Important Oysters from Goa, Central-West Coast of India.

The major beds of oyster along the central-west coast of India are exposed to different anthropogenic activities and are severely exploited for human consumption. In this viewpoint, tissues of oyster Crassostrea madrasensis, C. gryphoides and Saccostrea cucullata were analyzed for Cu, Ni, Cd and Pb concentrations (dry weight) from Chicalim Bay, Nerul Creek and Chapora Bay in pre-monsoon, monsoon and post-monsoon seasons. A higher concentration of Cu (134.4-2167.9mg kg-1) and Cd (7.1-88.5mg kg-1) was found, which is greater than the recommended limits in all the three species (and sites). Moreover, significant (p < 0.05) variations were observed for all the metals concentrations among the species, seasons and sites. The high concentrations of Cd and Cu in tissues of edible oyster pose a threat to human health. Therefore, continuous monitoring, people awareness and a stringent government policy should be implemented to mitigate the metal pollution along the studied sites.

Histopathological effect and stress response of mantle proteome following TBT exposure in the Hooded oyster Saccostrea cucullata

Tributyltin (TBT), an environmental pollutant in marine ecosystems, is toxic to organisms. Although contamination by and bioaccumulation and toxicity of this compound have been widely reported, its underlying molecular mechanisms remain unclear. In the present study, we exposed the Hooded oyster Saccostrea cucullata to TBT to investigate histopathological effects and proteome stress response. Animals were exposed to three TBT sub-lethal concentrations, 10, 50 and 150 μg/l for 48 h. TBT produced stress leading to histopathological changes in oyster tissues including mantle, gill, stomach and digestive diverticula. TBT induced mucocyte production in epithelia and hemocyte aggregation in connective tissue. Cell necrosis occurred when exposure dosages were high. Comparative proteome analyses of mantle protein of oysters exposed to 10 μg/l and control animals were analyzed by a 2-DE based proteomic approach. In total, 32 protein spots were found to differ (p < 0.05). Of these, 17 proteins were identified which included 14 up-regulated and 3 down-regulated proteins. TBT induced the expression of proteins involved in defensive mechanisms (HSP-78, HSP-70, aldehyde dehydrogenase and catalase), calcium homeostasis (VDAC-3), cytoskeleton and cytoskeleton-associated proteins, energy metabolism and amino acid metabolism. Our study revealed that TBT disturbs calcium homeostasis via VDAC-3 protein in mantle and this probably is the key molecular mechanism of TBT acting to distort shell calcification. Moreover, proteins involved in cell structure (tubulin-alpha and tubulin-beta) and protein synthesis were reduced after TBT exposure. Additionally, differential proteins obtained from this work will be useful as potential TBT biomarkers.

和歌山県みなべ町目津崎におけるオハグロガキとケガキの個体群生態,1991~2011年

和歌山県みなべ町目津崎におけるオハグロガキとケガキの個体群生態,1991~2011年

Distribution of Norovirus in Fecal-Contaminated Oyster (Saccostrea cucullata and Solen roseomaculatus) Tissues in Vitro

ABSTRACTNoroviruses are a common major cause of acute gastroenteritis in humans and are mainly associated with oyster consumption. In this investigation, 30 oysters of each of the two species (Saccostrea cucullata and Solen roseomaculatus) were collected from the northern Persian Gulf. Oysters have been exposed to norovirus genogroup II, genotype 4 (GII.4), artificially. The analysis of the contaminated oysters was carried out in three periods of time. Different oyster tissues were removed and tested for norovirus contamination, using conventional reverse transcriptase-polymerase chain reaction assay, while comparing the efficiency of two different sets of primers. Similar to previous observations in other species, these results indicated that norovirus genogroup II is mainly accumulated in the digestive diverticula of S. cucullata and S. roseomaculatus.

Early embryo and larval development of inviable intergeneric hybrids derived from Crassostrea angulata and Saccostrea cucullata

To detect the intergeneric hybridization between the oyster Crassostrea angulata and Saccostrea cucullata coexisting along the southern coast of China, reciprocal crosses were conducted between the two species. Barriers for sperm recognizing, binding, penetrating the egg, and forming the pronucleus were detected by fluorescence staining. From the results, although fertilization success was observed in hybrid crosses, the overall fertilization rate was lower than that of intraspecific crosses. A large number of hybrid larvae died at 6–8 d after hatching, and those survived could not complete metamorphosis. C. angulata ♀× S. cucullata ♂ larvae had a growth rate similar to that of the maternal species, whereas S. cucullata ♀ × C. angulata ♂ larvae grew the slowest among all crosses. Molecular genetics analysis revealed that hybrid progeny were amphimixis hybrids. This study demonstrated that hybrid embryos generated by crossing C. angulata and S. cucullata could develop normally to the larval state, but could not complete metamorphosis and then develop to the spat stage. Thus, there is a post-reproductive isolation between C. angulata and S. cucullata.

Chemical Composition of the Edible Oyster Shell Crassostrea Madrasensis (Preston 1916)

Oysters coming under the Genus, Crassostrea and Saccostrea are observed along the Indian coasts. Among them four species are considered economically important including Crassostrea madrasensis[1], Crassostrea gryphoides (Schlothein 1813), Crassostrea rivularis (Gould, 1850) and Saccostrea cucullata (Born, 1890). Crassostrea madrasensis, the dominant among them has been selected for this study. The procedure of analysis of the samples was based on AOAC 2005 standards. Flame Photometry, ICP and CHNS analysis was used to find out the precise values for Ca and Na; Sr and Mg; and C and S respectively in the shell of Crassostrea madrasensis. Calcium as calcium oxide was observed as the largest constituent at 47.49% closely followed by total Carbon at 43.87%. The remaining elements Sodium as sodium oxide at 1.119%, Magnesium as magnesium oxide at 0.619%, Sulfur as sulfur dioxide at 0.403%, Strontium as strontium oxide at 0.020% and water as moisture exist only in negligible percentages. The utilization of oyster shell relates to the chemical constituents which contribute more than 90% of the shell. In Crassostrea madrasensis, these elements have been identified as Calcium and Carbon and have been quantified as contributing on an average 91.36% by weight of the shell in this study. These can effectively be used in the pharmaceutical, fertilizer, lime, cement and poultry feed industries.

Complete mitochondrial DNA sequences of Saccostrea mordax and Saccostrea cucullata: genome organization and phylogeny analysis

Classified in the phylum mollusks, oysters are bivalves which are found in estuaries and coastal zones. Because of their plastic shell, mitochondrial DNA analysis of this species becomes an interesting field, necessary to investigate their phylogenetic and evolution of relations. In our study, two oyster species: Saccostrea mordax and Saccostrea cucullata from Indian Ocean (Madagascar) were investigated. The complete sequence of Saccostrea mordax (16 512 bp) and Saccostrea cucullata (16 396 bp) were described and determined, with their mitogenomes deposited in the GenBank with accession number KP769562 and KP967577 respectively. Both mitochondrial genome sequences contained 12 protein-coding genes, 23 tRNAs, and two rRNAs, all encoded in the same heavy strand. High levels of similarity in the gene arrangement of the two Saccostrea species were evident. The phylogenetic analysis shows a closer relationship between the two Saccostrea species and confirms the strong relationship within Saccostrea, Crassostrea and Ostrea genus in taxonomy of Ostreidae family.

Trace metals in water, sediment and bivalves of a tropical estuary, west coast of India

Trace metal pollution was studied in water, sediment and three selected bivalves in Mandovi and Chapora estuaries of Goa. The trace metal in water and sediment of Mandovi was higher than in Chapora. The concentration in the tissues was in the range of 1205.2–2506.7ppm for Paphia malabarica, 1906.2–2802.6ppm for Perna viridis and 778.7–1607.5ppm for Saccostrea cucullata in Mandovi estuary. Tha values for Chapora were 199.4–625.8ppm for P. malabarica, 812.6–1220.2 for P. viridis and 392.5–418.6ppm for S. cucullata. The anthropogenic input of metal in Mandovi estuary appears to be mainly responsible for the high accumulation of trace metals. These bivalves have potential to serve as indicator for metal contamination in seafood of Goa.

EFFECT OF DYNAMICAL WATER QUALITY ON SHRIMP CULTURE IN THE INTEGRATED MULTITROPIC AQUACULTURE (IMTA)

One of the technologies to improve the productivity of shrimp farms are environmentally friendly shrimp farming multitrophic integrated system known as Integrated Multitrophic Aquaculture (IMTA). The aims of the study were to observe the water quality dynamic on the integrated multitrophic aquaculture and the effect on the production. This study was used four plots which each of pond had 4,000 m2 in sizing, located in experiment pond, at Research and Development Institute for Coastal Aquaculture, Maros. The main commodities used were tiger and vannamei shrimp. In the A pond was cultivated the tiger shrimp with density 12 ind./m2, in B pond was tiger shrimp with density 8 ind./m2, C pond was vannamei shrimp with density 50 ind./m2, and D pond was vannamei shrimp with density 25 ind./m2. Other commodities were red tilapia (Oreochromis niloticus). Each pond had stocking density 2,400 ind./plot which was divided into 5 hapas having a size of (6 m x 4 m x 1.2 m)/each, mangrove oysters (Crassostrea iredalei and Saccostrea cucullata) with density 7,500 ind./4,000 m2 and seaweed (Gracilaria verrucosa) of 500 kg/4,000 m2. The observation of dynamic water quality in the pond was conducted every day i.e. temperature, dissolved oxygen, salinity, and measured pH, while the total organic matter total (TOM), total ammonia nitrogen (TAN), nitrite, nitrate, phosphate were taken every two weeks. The measurements methods of water quality in laboratory was refered to APHA (2008); and Boyd (1990). During the study, absorption of N and P in seaweed were measured, the obtained plankton was identified and the ratio of carbon and nitrogen during the observation was also calculated. To determine the effect of dominant water quality on production was used the principal component analysis (PCA). The result showed that water quality during the study was suitable for shrimp and red tilapia culture. The dominant water qualities which effected the shrimp production in IMTA system were total ammonia nitrogen (TAN), oxygen, total organic matter (TOM), phosphate, and salinity. The survival rate of the tiger shrimp in intensive pond and semi intensive pond was 50.68% and 59.28% respectively, while the survival rate of the vannamei shrimp in intensive and semi intensive was 71.26% and 68.06% respectively. The highest shrimp production in the cultivation of IMTA reached was 1,488 kg/pond (3,720 kg/ha) in C pond. The lowest feed conversion ratio (FCR) was obtained in the D pond (0.89). The highest production of red tilapia in IMTA reached in C pond (426.65 kg/pond).

Polycyclic aromatic hydrocarbons in the largest deepwater port of East China Sea: impact of port construction and operation.

PAHs were analyzed for samples of seawater, sediment, and oyster (Saccostrea cucullata) collected from Yangshan Port, East China between 2012 and 2013. Concentrations of ∑PAHs in seawater (180-7,700 ng/L) and oyster (1,100-29,000 ng/g dry weight (dw)) fell at the higher end of the global concentration range, while sediment concentrations (120-780 ng/g dw) were generally comparable to or lower than those reported elsewhere. PAHs in the particulate phase accounted for 85% (52-93%) of the total PAHs in seawater. Congener profile analysis revealed that PAHs in waters originate mainly from petrogenic sources, while high-temperature combustion processes are the predominant sources for sediment. ∑PAHs in oyster well correlated with ∑PAHs in the particulate phase, suggesting particle ingestion as an important pathway for bioaccumulation of PAHs. Cancer risk assessment of PAHs in oyster indicated high human health risks posed by these chemicals to the coastal population consuming this seafood.

Actuopaleontological characterization and molluscan biodiversity of a protected tidal flat and shallow subtidal at the northern Red Sea

Tidal flats are abundantly developed throughout the Phanerozoic but actualistic studies on subtropical‒tropical tidal flats are rare. This study of a tidal flat and shallow subtidal of a lagoon protected behind a fringing reef at the northern Red Sea is therefore aimed to contribute to the understanding of the distribution and abundance of paleontologically relevant fauna and its lebensspuren. Muddy sands to sands and beachrock are the predominating benthic habitats. Important ecosystem engineers are the oyster Saccostrea cucullata, which forms decimeter- to meter-scale bioherms in the lower intertidal, the ocypodid crab Dotilla sulcata, which reaches highest abundances on the tidal flat, some tens of meters from the low-tide line, and the callianassid decapod Paratrypaea bouvieri, which is very abundant in the subtidal. The sediment surface in the intertidal was densely covered with lebensspuren of gastropods. Quantitative and qualitative samples revealed 130 species of molluscs from 51 families. Most species found belong to the Veneridae, Lucinidae, Turridae, Cardiidae, Trochidae, and Pyramidellidae in the subtidal and to the Cerithiidae in the intertidal, but overall only 32 species were found alive (13 on the tidal flat, 28 in the subtidal). Distinct assemblages of living and dead molluscs characterized the intertidal and subtidal, which suggests that dead shells can be used to assess regional biodiversity. Numerically, the living assemblage on the tidal flat was strongly dominated by the deposit-feeding potamidid gastropod Pirenella conica, and in the subtidal by infaunal bivalves (Glycymerididae, Lucinidae, Tellinidae, and Veneridae). Predatory gastropods (Naticidae, Melongenidae, Fasciolariidae, Muricidae, and Conidae) were accessory components that were mostly present in qualitative samples in the subtidal and lower intertidal. Accordingly, frequencies of drilling predation for the total assemblage are significantly higher in the subtidal (25.7 %) than in the intertidal (1.2 %). We conclude that the preservable fauna and its lebensspuren are characteristically developed along an environmental gradient and suitable to distinguish intertidal from subtidal habitats in a potential fossil record.

Variability in age and growth of common rock oysterSaccostrea cucullata(Bivalvia) in Ascension Island (central-east Atlantic)

Common rock oystersSaccostrea cucullata(Bivalvia) were sampled from intertidal volcanic rocks at five sites around Ascension Island (central-east Atlantic) in austral winter 2012–2014. Their left valves were sectioned to reveal annual growth increments. Their periodicity was validated by the presence of specific growth marks in the increment sequence visible in consecutive years of sampling. No significant differences in shell height-weight relationships were revealed between sites. Marginal analysis of the increment width showed thatS. cucullataaccelerated their growth in cooler winter months and decelerated the growth in warmer summer months. Rock oysters in Ascension Island lived up to 14–16 years with maximum age of 26 years. Young oysters (1–5 years old) had the same growth rates both in shell height and weight in all sites. However, their starting point (size and weight of 1-year-old animals) was different in various sites, with largest animals occurring in the most protected site Northeast Bay with sheltered inlets and smallest animals inhabiting exposed to surf site of Letterbox. Growth in shell height was best described by von Bertalanffy growth function with the largestL∞in animals inhabiting the windward side and smallest animals occurring in the leeward side of the Island. In summary,S. cucullataaround Ascension Island lived longer but had slower growth than those from tropical regions of Southwest Asia probably due to comparatively low productivity observed in the central part of the equatorial tropical Atlantic.

Biotransformation and detoxification of inorganic arsenic in Bombay oyster Saccostrea cucullata

Arsenic (As) exists as the toxic inorganic forms in marine water and sediment, while marine oysters usually accumulate high As contents mostly as the less toxic organic forms. It has not yet been clear that how As is biotransformed in marine oysters. This study therefore investigated the biotransformation and detoxification of two inorganic As forms (As(III) and As(V)) in Bombay oyster Saccostrea cucullata after waterborne exposures for 30 days. Seven treatments of dissolved As exposure (clean seawater, 1, 5, 20mg/L As(III), and 1, 5, 20mg/L As(V)) were performed. Body As concentration increased significantly after all As exposure treatments except 1mg/L As(V). Total As, As(III), and As(V) concentration were positive correlated with glutathione-S-transferases (GST) activities, suggesting GST might play an important role in the As biotransformation and detoxification process. Organic As species were predominant in control and the low As exposed oysters, whereas a large fraction of As was remained as the inorganic forms in the high As exposed oysters, suggesting As could be biotransformed efficiently in the oysters in clean or light contaminated environment. The results of As speciation demonstrated the As biotransformation in the oysters included As(V) reduction, methylation to monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), and subsequent conversion to arsenobetaine (AsB). More As was distributed in the subcellular metallothionein-like proteins fraction (MTLP) functioning sequestration and detoxification in the inorganic As exposed oysters, suggesting it was also a strategy for oysters against As stress. In summary, this study elucidated that marine oysters had high ability to accumulate, biotransform, and detoxify inorganic As.

Effect of microbial load on the condition index of the edible oyster, Saccostrea cucullata in the Sundarbans, India

The effect of microbial load on the condition Index of the edible oyster, Saccostrea cucullata were analysed on monthly basis during 2010 and 2011 from the three different stations (Namkhana, Frasergaunge and Sajnekhali) of Indian Sundarbans. The results showed significant variation with respect to microbial load between stations and seasons, which is reflected in the tissue of edible oyster. Significant positive correlations were observed between microbial load of the ambient environment and the tissue system of oyster. The Condition Index of the oyster species also exhibited negative correlation with the microbial load of oyster tissue, which confirms the negative stress induced by microbes on the growth and survival of the species.