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1.
The influence of seasonal and environmental parameters on the occurrence of bacteria was investigated in two clam species (Venerupis pullastra and Ruditapes philippinarum), water and sediment from the Tagus estuary. Total viable counts (TVC), Escherichia coli, Salmonella spp. and Vibrio spp. were evaluated during one-year. Overall, significant seasonal variations were found in both sampling sites, especially for E. coli and Vibrio spp. levels. In summer, significantly higher Vibrio spp. levels were found in R. philippinarum and sediment samples, but not in V. pullastra clams and water samples. In contrast, significantly higher TVC and E. coli levels were observed in winter months in water and sediment samples. Salmonella spp. was generally isolated when higher levels of E. coli were detected, particularly in R. philippinarum. This study is useful for authorities to develop monitoring strategies for coastal contamination and to estimate human health risks associated with the consumption of bivalves.  相似文献   

2.
There are mainly distributed three pedigrees (White, Liangdao Red, and Zebra) of Manila clam Ruditapes philippinarum in Yantai population along the Bohai marine and coast. However, the biological differences to environmental stressors have been ignored in toxicology studies, which could lead to the distortion of biological interpretations of toxicological effects induced by environmental contaminants. In this study, we applied a system biology approach, metabolomics to compare the metabolic profiles in digestive gland from three pedigrees of clam and characterize and compare the metabolic responses induced by mercury in clam digestive gland tissues to determine a sensitive pedigree of clam as a preferable bioindicator for metal pollution monitoring and toxicology research. The most abundant metabolites, respectively, included branched‐chain amino acids, alanine, and arginine in White samples, glutamate, dimethylglycine, and glycine in Zebra clams and acetylcholine, betaine, glucose, and glycogen in Liangdao Red clams. After 48 h exposure of 20 µg L?1 Hg2+, the metabolic profiles from the three pedigrees of clams showed differentially significant changes in alanine, glutamate, succinate, taurine, hypotaurine, glycine, arginine, glucose, etc. Our findings indicate the toxicological effects of mercury exposure in Manila clams including the neurotoxicity, disturbances in energetic metabolisms and osmoregulation in the digestive glands and suggest that Liangdao Red pedigree of clam could be a preferable bioindicator for the metal pollution monitoring based on the more sensitive classes of metabolic changes from digestive glands compared with other two (White and Zebra) pedigrees of clams.  相似文献   

3.
《Marine pollution bulletin》2008,56(10-12):485-493
Variation of polycyclic aromatic hydrocarbons (PAHs) levels was assessed in Tapes philippinarum from the Lagoon of Venice. Clams were transplanted from a polluted area next to Porto Marghera to two rearing areas of the Southern Lagoon. Analyses of PAHs were made in sediments and clams by GC/MS at first sampling and after 30, 60 and 180 days. Principal component analysis was performed to elucidate bioaccumulation and depuration pattern and input sources. Biota-Sediment-Accumulation-Factor (BSAF) was applied to evaluate the PAHs input sources from sediment. Condition index was calculated to compare the seasonal variation of clam tissue to PAHs levels. To propose results not affected by seasonal changes in flesh weight of clams, the approach based on the calculation of PAHs/SW index was applied. From the results, it was concluded that PAHs/SW index is more recommendable to asses temporal variation of PAHs levels in Manila clams.  相似文献   

4.
《Marine pollution bulletin》2009,58(6-12):307-312
Since increased ventilation is known to be a common strategy used by aquatic animals to cope with hypoxia, we tested in present study the hypothesis that hypoxia can promote the bioaccumulation of naphthalene, a representative polycyclic aromatic hydrocarbon (PAH), in Penaeus aztecus, a penaeid shrimp subject to hypoxia and PAH contamination in the northern Gulf of Mexico. For each of the two naphthalene concentrations, five groups of shrimps were, respectively, subjected to five different conditions, namely, clean seawater under normoxia, seawater containing acetone under normoxia and hypoxia, and seawater containing 10 or 250 μg/L naphthalene under normoxia and hypoxia. Our results suggest that hypoxia does not significantly alter naphthalene bioaccumulation in either the gills or the hepatopancreas of P. aztecus. The absence of a promoting effect of hypoxia on naphthalene bioaccumulation is attributed to the increased disposition of naphthalene when the shrimps are subjected to hypoxia.  相似文献   

5.
《Marine pollution bulletin》2014,78(1-2):137-145
To examine the influence of habitat alteration by tideflat reclamation on the physiological ecology of Ruditapes philippinarum, seasonal variations in its condition, gross biochemical composition, and reproductive cycle were compared for a yearly cycle between a reclaimed flat (Gomsohang, GS) and a natural flat (Hajun, HJ) in Gomso Bay, Korea. Concentrations of chlorophyll a and seston (as well as its energy value as food available to the clam) were consistently higher at HJ than at GS. Condition, dry tissue weight, and energy reserves (proteins and carbohydrates) of the clams were much higher at HJ than at GS during spring–summer, when fast growth and gametogenic development occur. Furthermore, their spring gametogenic development and spawning were advanced at HJ compared with GS. Our results suggest that the Manila clam encounters nutritionally stressful environmental conditions in altered habitats after tideflat reclamation that lead to lowered nutrient accumulation and a changing reproductive cycle.  相似文献   

6.
Bottom aquaculture of bivalves is a high-yield culture method, which is increasingly adopted by shellfish farmers worldwide. However, the effects of bottom aquaculture on benthic ecosystems are not well-known. Manila clam (Ruditapes philippinarum), is a widely distributed bottom aquaculture mollusk species. To assess the ecological impacts of Manila clam bottom aquaculture, clams and other macrofaunal assemblages were investigated during four cruises (July and November 2011, February and May 2012) at six sampling sites in Jiaozhou Bay, China. Correlation analysis showed that macrofaunal assemblages had significant negative correlations with the abundance of Manila clams. However, according to the results of several biotic indices, a low disturbance was detected by Manila clam bottom aquaculture. In conclusion, AMBI (AZTI'S Marine Biotic Index) and M-AMBI (Multivariate AZTI Marine Biotic Index) indices are more suitable for assessing ecological quality than polychaete/amphipod ratios when the disturbance is slight, such as at a bivalve bottom aquaculture.  相似文献   

7.
Variation of polycyclic aromatic hydrocarbons (PAHs) levels was assessed in Tapes philippinarum from the Lagoon of Venice. Clams were transplanted from a polluted area next to Porto Marghera to two rearing areas of the Southern Lagoon. Analyses of PAHs were made in sediments and clams by GC/MS at first sampling and after 30, 60 and 180 days. Principal component analysis was performed to elucidate bioaccumulation and depuration pattern and input sources. Biota-Sediment-Accumulation-Factor (BSAF) was applied to evaluate the PAHs input sources from sediment. Condition index was calculated to compare the seasonal variation of clam tissue to PAHs levels. To propose results not affected by seasonal changes in flesh weight of clams, the approach based on the calculation of PAHs/SW index was applied. From the results, it was concluded that PAHs/SW index is more recommendable to asses temporal variation of PAHs levels in Manila clams.  相似文献   

8.
Cadmium (Cd) has become an important heavy metal contaminant in the sediment and seawater along the Bohai Sea and been of great ecological risk due to its toxic effects to marine organisms. In this work, the toxicological effects caused by environmentally relevant concentrations (10 and 40 µg L?1) of Cd were studied in the gill tissues of Manila clam Ruditapes philippinarum after exposure for 24, 48, and 96 h. Both low (10 µg L?1) and high (40 µg L?1) doses of Cd caused the disturbances in energy metabolism and osmotic regulation and neurotoxicity based on the metabolic biomarkers such as succinate, alanine, branched chain amino acids, betaine, hypotaurine, and glutamate in clam gills after 24 h of exposure. However, the recovery of toxicological effects of Cd after exposure for 96 h was obviously observed in clam to Cd exposures. Overall, these results indicated that NMR‐based metabolomics was applicable to elucidate the toxicological effects of heavy metal contaminants in the marine bioindicator.  相似文献   

9.
Since increased ventilation is known to be a common strategy used by aquatic animals to cope with hypoxia, we tested in present study the hypothesis that hypoxia can promote the bioaccumulation of naphthalene, a representative polycyclic aromatic hydrocarbon (PAH), in Penaeus aztecus, a penaeid shrimp subject to hypoxia and PAH contamination in the northern Gulf of Mexico. For each of the two naphthalene concentrations, five groups of shrimps were, respectively, subjected to five different conditions, namely, clean seawater under normoxia, seawater containing acetone under normoxia and hypoxia, and seawater containing 10 or 250 μg/L naphthalene under normoxia and hypoxia. Our results suggest that hypoxia does not significantly alter naphthalene bioaccumulation in either the gills or the hepatopancreas of P. aztecus. The absence of a promoting effect of hypoxia on naphthalene bioaccumulation is attributed to the increased disposition of naphthalene when the shrimps are subjected to hypoxia.  相似文献   

10.
《Marine pollution bulletin》2014,80(1-2):211-219
Lipid and fatty acid (FA) composition and selected oxidative stress parameters of freshwater clams (Dipolodon chilensis), from a sewage-polluted (SMA) and a clean site, were compared. Trophic markers FA were analyzed in clams and sediment. Saturated FA (SAFA), and bacteria and sewage markers were abundant in SMA sediments, while diatom markers were 50% lower. Proportions of SAFA, branched FA, 20:5n − 3 (EPA) and 22:6n − 3 (DHA) were higher in SMA clams. Chronic exposure of D. chilensis to increasing eutrophication affected its lipid and FA composition. The increase in EPA and DHA proportions could be an adaptive response, which increases stress resistance but could also lead to higher susceptibility to lipid peroxidation TBARS, lipofuscins (20-fold) and GSH concentrations were higher in SMA clams. FA markers indicated terrestrial plant detritus and bacteria are important items in D. chilensis diet. Anthropogenic input in their food could be traced using specific FA as trophic markers.  相似文献   

11.
The effects of 4-nonylphenol on anti-oxidant enzyme (superoxide dismutase and catalase) activity in both gills and digestive gland and re-burrowing capability of the clam Tapes philippinarum were investigated after 7 days' exposure to various sublethal concentrations of nonylphenol (NP). NP caused a significant decrease in superoxide dismutase activity in both tissues from the lowest concentration tested, whereas no significant alteration with respect to controls was observed in catalase activity. NP effects on re-burrowing of clams were evaluated in two experiments. In the first, clams exposed to the highest NP concentrations showed a marked delay in re-burrowing 48 h after the end of exposure. Modifications in normal burrowing behaviour were also observed, suggesting that NP acts via narcosis and/or neurotoxic mechanisms. In the second experiment, the elapsed time for 50% of the exposed clams to re-burrow into the sediment (RT(50)) was also calculated in a 24-h re-burrowing response test. At the highest NP concentrations, it was not possible to estimate RT(50) values, as the percentage of clams showing complete burial was less than 50%. The present study demonstrates that NP causes oxidative stress by inhibiting superoxide dismutase activity and greatly affects the re-burrowing capability of T. philippinarum, even at environmentally realistic concentrations.  相似文献   

12.
《Marine pollution bulletin》2008,56(10-12):579-590
Habitat Suitability (HS) models have been extensively used by conservation planners to estimate the spatial distribution of threatened species and of species of commercial interest. In this work we compare three HS models for the estimation of commercial yield potential and the identification of suitable sites for Tapes philippinarum rearing in the Sacca di Goro lagoon (Italy) on the basis of six environmental factors. The habitat suitability index (HSI) is based on expert opinion while the habitat suitability conditional (HSC) is calibrated on observational data. The habitat suitability mixed (HSM) model is a two-part model combining expert knowledge and regression analysis: the first component of the model uses logistic regression to identify the areas in which clams are likely to be present; the second part applies the same parameter-specific suitability functions of the HSI model only in the areas previously identified as productive by the logistic component.The HS models were validated on an independent data set and estimates of potential yield of the Goro lagoon were compared. The effectiveness of the three approaches is then discussed in terms of predicted yield and identification of suitable sites for farming.  相似文献   

13.
Concentrations of benzo[a]pyrene (BAP) were measured in subpopulations of softshell clams, Mya arenaria, from four intertidal sites in Coos Bay from June 1976 to June 1978. Subsequently, concentrations of 15 unsubstituted polynuclear aromatic hydrocarbons (PNAH) were determined in two subpopulations from September 1978 to August 1979. There were significant differences between BAP concentrations in clams from the four sites. For the two-year period, they were highest in clams inhabiting areas adjacent to the industrialized bayfront and lowest in clams inhabiting more remote areas. There were no significant seasonal variations in BAP concentrations during this period. During the 1978–1979 study, the average total PNAH concentration in clams from the bayfront area was 555.1 μg kg?1 compared to 76.3 μg kg?1 for clams from a more remote environment. In general, PNAH concentrations were lowest in the fall-winter and highest during the spring-summer.  相似文献   

14.
The Manila clam Ruditapes philippinarum cultivation is an original shellfish farming activity strongly mechanized. In the Chausey archipelago (France) this activity settles on the Lanice conchilega beds, habitat known to host a rich and diversified benthic macrofauna and which is an attractive feeding ground for birds. A first study highlighted that this activity had strong negative effects on the L. conchilega beds and their associated benthic macrofauna. Here we assess the impacts of such an activity on the Eurasian Oystercatcher Haematopus ostralegus for which Chausey is one of the most important national breeding sites and which is also a common species in winter, spring and autumn migrations. We found that Oystercatchers significantly selected the L. conchilega beds to feed and that their spatial distribution was significantly modified after the creation of new clam concessions. In a context of a growing disappearance of pristine coastal ecosystems for the benefit of anthropo-ecosystems, we discuss the problem of the degradation of such benthic habitats with a low resilience which may loose their high functional value.  相似文献   

15.
Green-lipped mussels, Perna viridis, and Manila clams, Ruditapes philippinarum were sourced from “clean” sites in the Hong Kong region, depurated in a laboratory using uncontaminated filtered seawater for 8 days, and transplanted to a suspected gradient of chemically polluted sites in Hong Kong. After 14- and 28-days of field exposure, several antioxidant parameters including glutathione S transferase (GST), catalase (CAT), glutathione peroxidase (GPx), and glutathione (GSH) were quantified in gill and hepatopancreas tissues. Whole body tissue concentrations of polycyclic aromatic hydrocarbons (PAHs), petroleum hydrocarbons (PHCs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCs) were determined in pooled site samples. Chemical analyses indicated that: (a) clams had higher levels of PAHs, PHCs, DDTs and PCBs, whereas mussels had higher hexachlorocyclohexane (HCHs) and there was no difference between species for dieldrin and remaining OCs; (b) Kat O should not be continued as a “clean” reference site for Hong Kong, because of the levels of contaminants measured and (c) PAH concentrations in the current survey were similar to those previously measured. Toxicological conclusions were: (a) antioxidant responses were different between species; (b) CAT and GST have highest utility in clams for field use in Hong Kong, whereas CAT in both gill and hepatopancreas tissue showed most potential in mussels; (c) significant induction of antioxidant responses over day 0 (excluding GPx in both tissues, and GST in mussel hepatic tissue); (d) groups of contaminants do not consistently induce antioxidant responses and (e) organochlorines and PCBs correlated significantly with CAT and GST in clam hepatopancreas and with CAT in mussel gill and hepatic tissue. Multivariate statistical techniques indicated little relationship between the site patterns for antioxidant responses and the contaminant gradients identified in body burden analysis.  相似文献   

16.
Gravel sediment freshly enriched with over 4.4 μg Cu g?1 significantly increased the burrowing and reburrowing times of Littleneck marine clams (Protothaca staminea). Abnormal burrowing behaviour was observed with time-lapse video. Aged (1 day) copper-enriched sediment did not affect clam burrowing time. Copper in sediment porewater declined three days after sediment enrichment to background levels without change in total sediment copper. In a long-term experiment, clams with increased burrowing time into copper-enriched sediment had up to 25% mortality after 12–29 days burial in the sediment. The majority of clam mortality was found in clams burrowing within the first 48 h. Over 7 weeks there was blackening of sediment and clam shells proportional to sediment copper enrichment.  相似文献   

17.
Sperm production and motility, fecundity, and egg size, complexity and viability of serpulid polychaetes Hydroides elegans and Hydroides diramphus after 2-week treatment to hypoxia (2 mg O2 l−1) was compared with those under normoxia (6 mg O2 l−1). Despite reduced fecundity, the effect of parental hypoxic exposure on gamete quality was not discernible for both species. However, regardless of their subsequent dissolved oxygen environment, eggs spawned by H. elegans after hypoxic exposure were found to have lower fertilization success, slower embryonic development and a significantly higher yield of malformed embryos than those with a parental normoxic treatment. In contrast, neither fertilization success nor rate of embryonic development was affected for H. diramphus. The results implied that hypoxia was a potential stress reducing the recruitment of H. elegans through non-adaptive epigenetic effect, whereas H. diramphus was a more tolerant species to survive hypoxic events.  相似文献   

18.
Sublethal effects of estuarine sediments containing high levels of heavy metals were studied using the marine bivalve, Macoma balthica. Burrowing behaviour was inhibited in all contaminated sediments compared to the control. The time required for 50% of the population to burrow (ET50) ranged from 0.17 h in the control to 4.8 h in the most contaminated substrate. A comparison of linear regressions of the concentrations of individual metals in the sediments vs the burrowing response times showed the regressions for mercury and cadmium to be significant (P < 0.05 and < 0.001 respectively). An active threshold avoidance response by burrowed M. balthica was also demonstrated as clams showed a significant (P < 0.05) avoidance of the sediment containing the highest metal levels. Both behavioural responses were considered useful sublethal tests to assess the impact of polluted sediments.  相似文献   

19.
The burrowing responses of a common tropical bivalve, the short-neck clam Ruditapes philippinarum, to cadmium (Cd)-spiked sediment, variations of sediment grain size and natural sediments collected from 15 locations in Hong Kong's inshore waters were investigated through a series of laboratory tests. Results showed that the burrowing response exhibited a negative relationship with an increase in Cd concentration in the spiked sediments. The level of Cd was also found to be directly proportional to the percent mortality of the clam. However, there was no significant difference (p>0.05) in the time elapsed for the clam to burrow into sediments with different grain size composition. The elapsed time for 50% of the test clams to burrow into the sediment (ET50) over a period of 48 h was calculated for the sediment samples collected from the 15 locations. Results of ANOVA showed significant difference (p<0.05) among the sediment samples. Tukey's multiple comparison test revealed two groups of sediments: group 1 containing 3 sediment samples collected from Victoria Harbour and group 2 containing 12 samples obtained from other coastal areas of Hong Kong. The ET50 value for group 1 sediments was found to be greater than 2880 min whilst the ET50 for group 2 sediments had a mean of 173.9 min. Agglomerative classification of the sediment samples, based on metal content (As, Cd, Cr, Cu, Ni, Pb, Zn), also showed two similar groups, suggesting that the ET50 values were correlated with the metal level of the sediment samples. Group 1 sediments collected from Victoria Harbour had greater concentrations of Cd, Cr, Cu, Ni and Zn as compared to that in group 2. The present study demonstrated that high metal content in the sediment tends to inhibit the burrowing responses of the clam and that there is potential to develop the burrowing responses of R. philippinarum as a sublethal sediment toxicity test.  相似文献   

20.
《Marine pollution bulletin》2012,64(5-12):189-194
The harmful alga Chattonella marina has caused massive fish kills and economic losses worldwide. However, the fish kill mechanisms by C. marina have not been identified. The present study has confirmed that a significant elevation of blood osmolality is the universal response in moribund fish exposed to C. marina and the possible reasons leading to contradictory reports were identified. Both osmotic distress and respiratory impairment are important mechanisms leading to fish kill by C. marina. The susceptibility of marine fish to C. marina appears to be inversely related to their tolerance to hypoxia, with the hypoxia intolerant goldlined seabream being the most susceptible, and the hypoxia tolerant green grouper being the most tolerant to C. marina. Further studies in the marine medaka (Oryzias melastigma) showed that fish susceptibility to C. marina is directly related to susceptibility of the fish to hypoxia, but not related to its tolerance to hypersalinity stress.  相似文献   

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