Toxicities of ten metals to Crassostrea gigas and Mytilus edulis embryos and Cancer magister larvae

Pacific oyster (Crassostrea gigas Thunberg) embryos, bay mussel (Mytilus edulis Linnaeus) embryos, and Dungeness crab (Cancer magister Dana) zoea I stage larvae were exposed to arsenic, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, and zinc salts. The two bivalve species were exposed through the completion of embryogenesis (48 h), and the effects of the metals upon abnormal development were monitored. The crab larval stages were exposed to the metal solutions for 96 h. Concentrations (μg l_.^?1 as metal) which caused 50% abnormal development in the two species of bivalve larvae and which were fatal to 50% of the crab larvae ranged from 5.3 (oyster) to 49 (crab) for copper; 5.8 (mussel) to 8.2 (crab) for mercury; 14 (mussel) to 55 (crab) for silver; 119 (oyster) to 456 (crab) for zinc; 232 (crab) to 3000 (mussel) for arsenic; 247 (crab) to 1200 (mussel) for cadmium; 349 (oyster) to 4360 (crab) for nickel; 476 (mussel) to 758 (oyster) for lead; 3440 (crab) to 4538 (oyster) for hexavalent chromium; and selenium greater than 10 000 for the three species. The acute toxicity testing of C. gigas embryo together with two California native species confirmed its usefulness for predicting toxicity to the latter species.     

Seasonal variation in the trace metal content of Mytilus edulis

The possible seasonal variation in the trace metal content of the mollusc Mytilus edulis has been studied by analysing cadmium, cobalt, copper, lead, manganese, mercury, nickel and zinc in 560 individuals collected from the same mussel bed over a period of two years. A clearly discernible effect of size on metal concentration was detected. However, no seasonal trends could be seen in the data.     

Integrated biomarker assessment of the effects exerted by treated produced water from an onshore natural gas processing plant in the North Sea on the mussel Mytilus edulis

The biological impact of a treated produced water (PW) was investigated under controlled laboratory conditions in the blue mussel, Mytilus edulis. Mussel health status was assessed using an integrated biomarker approach in combination with chemical analysis of both water (with SPMDs), and mussel tissues. Acyl-CoA oxidase activity, neutral lipid accumulation, catalase activity, micronuclei formation, lysosomal membrane stability in digestive cells and haemocytes, cell-type composition in digestive gland epithelium, and the integrity of the digestive gland tissue were measured after 5 week exposure to 0%, 0.01%, 0.1%, 0.5% and 1% PW. The suite of biomarkers employed were sensitive to treated PW exposure with significant sublethal responses found at 0.01-0.5% PW, even though individual chemical compounds of PW were at extremely low concentrations in both water and mussel tissues. The study highlights the benefits of an integrated biomarker approach for determining the potential effects of exposure to complex mixtures at low concentrations. Biomarkers were integrated in the Integrative Biological Response (IBR/n) index.     

Evaluation of the carbon isotopic effects of NDIR and CRDS analyzers on atmospheric CO2 measurements

Non-dispersive infrared(NDIR) and cavity ring-down spectroscopy(CRDS) CO_2 analyzers use 12CO_2 isotopologue absorption lines and are insensitive to all or part of other CO_2-related isotopologues. This may produce biases in CO_2 mole fraction measurements of a sample if its carbon isotopic composition deviates from that of the standard gases being used. To evaluate and compare the effects of carbon isotopic composition on NDIR and CRDS CO_2 analyzers, we prepared three test sample air cylinders with varying carbon isotopic abundances and calibrated them against five standard cylinders with ambient carbon isotopic composition using CRDS and NDIR systems. We found that the CO_2 mole fractions of the sample cylinders measured by G1301(CRDS) were in good agreement with those measured by Lo Flo(NDIR). The CO_2 values measured by both instruments were higher than that of a CO_2 isotope measured by G2201i(CRDS) analyzer for a test cylinder with depleted carbon isotopic composition δ~(13)C =-36.828‰, whereas no obvious difference was found for other two test cylinders with δ~(13)C=-8.630‰ and δ~(13)C=-15.380‰, respectively. According to the theoretical and experimental results, we concluded that the total CO_2 mole fractions of samples with depleted isotopic compositions can be corrected on the basis of their 12CO_2 values calibrated by standard gases using Lo Flo and G1301 if the δ~(13)C and δ18O values are known.     

Nitrogen and carbon isotopic composition in the diamonds of Mbuji Mayi (Zaïre)

The concentration and isotopic composition of nitrogen, measured in large diamonds (gram size) from the Mbuji Mayi kimberlite district (Zaïre) show a large range of variation (100<N<2100 ppm, ?11.2<δ¹⁵N< +6.0). The¹⁵N-depleted nitrogen is associated with the higher nitrogen concentrations. The large diamonds are individually rather homogeneous in¹³C (range ofδ¹³C < 0.9‰) while variations occur within small octahedral diamonds from the same district (range up to 5.8‰). The total range ofδ¹³C variation is about the same for the large diamonds (?10.5 <δ¹³C < ?5.5), the small octahedral diamonds (?10 <δ¹³C < ?4.6), and the carbonates from local kimberlites (?11.8 < δ¹³C < ?5.5). The diamond carbon isotopic data could indicate a complex story of crystallization within a deep-seated system fractionating its carbon isotopes.The nitrogen results indicate that nitrogen in diamonds is, on the average, markedly depleted in¹⁵N (weighted average ?5.15‰) relative to atmosphere, sediments and upper mantle.     

Trace metals in southern Californian mussels

The intertidal mussel Mytilus californianus is a useful indicator of anthropogenic inputs of several trace metals off southern California. Highest metal concentrations were measured in the digestive glands, and no significant differences attibutable to sex were found for this tissue. The distribution of lead appears to be dominated by diffuse inputs, while those of copper, chromium, and silver are most related to urban point sources. No distinct pattern was observed for nickel or zinc.     

Variations in leaf characteristics of three species of angiosperms with changing of altitude in Qilian Mountains and their inland high-altitude pattern

In this study,39 leaf samples of three angiosperms(Betula albo-sinensis,tree species;and Caragana jubata and Berberis diaphana,shrub species) were collected in the middle-east parts at 2300–3640 m asl of the Qilian Mountains to study the variations of leaf characteristics of angiosperms with altitude change in inland high-altitude regions of China.Five leaf indexes,viz.epidermal cell density(ED),stomatal density(SD),stomatal index(SI),leaf vein density(VD) and carbon isotopic ratio(δ13C),were analyzed in laboratory.The results show that there are significant or even very significant linear correlations between the five indexes and altitude,of which SD,SI and VD exhibit a negative correlation with altitude,while ED and δ13C exhibit a positive correlation with altitude.Such a correlation assemblage is quite different from the situation in the low-altitude humid environment.Generally,only an assemblage of positive correlations can be observed between the indexes(viz.SD,SI and δ13C,etc.) and the altitude in the low-altitude humid environment,which were caused mainly by the plants' responses to the change of atmospheric CO2 concentration(Cα).However,an assemblage of the negative and positive correlations found here may be attributed mainly to the plants' responses to the change of physiological drought caused by change of low temperature,and here it is preliminarily called the inland high-altitude pattern of plant leaf variations.     

Trace elements in farmed and wild gilthead seabream, Sparus aurata

In the present study, we sought to determine the concentration of several trace elements (total and organic mercury, selenium, cadmium, lead, arsenic, copper, chromium, iron, manganese, molybdenum, vanadium and zinc) in muscle tissue of gilthead seabream (Sparus aurata), an edible finfish species that is widely cultured in the Mediterranean area. The phenomenon of bioaccumulation and bioamplification (especially of mercury) was investigated by comparing farmed fish with wild specimens of the same species. Farmed specimens showed mercury and arsenic concentrations significantly lower than wild specimens, and no relationship was found between mercury concentration and body size. The lower level of methylmercury in farmed fish has important implications for consumer health.     

Effects of 4-nonylphenol exposure in mussels (Mytilus galloprovincialis) and crabs (Carcinus aestuarii) with particular emphasis on vitellogenin induction

Since it is often difficult to estimate possible adverse effects due to contamination in selected ecosystems, multi-species biomonitoring may provide more information, taking into account different routes of exposure, ecological roles and metabolic capabilities of animals. In this context, we exposed for 7 days the mussel Mytilus galloprovincialis and the crab Carcinus aestuarii to 4-nonylphenol (NP), a well-known xenoestrogen. In mussels (0–0.2 mg NP l⁻¹), we measured NP bioaccumulation in soft tissues and vitellogenin (Vg)-like protein levels in digestive glands from both males and females by the alkali-labile phosphate assay (ALP). As no reference data were available for crab exposure, the NP 96-h LC₅₀ value was previously determined. Then, in sublethally exposed (0–1.0 mg NP l⁻¹) male crabs, NP bioaccumulation and Vg levels were measured in hemolymph, gonads and digestive gland. Bioaccumulation of NP increased from 43 to 371 μg g⁻¹ d.w. in mussels, and from 3.6 to 37 μg g⁻¹ d.w. in crabs, depending on the NP concentration in water. Dose-dependent Vg-like protein induction was observed in both species, appearing to be related to NP bioaccumulation, although a partial decrease was recorded at the highest concentration tested. A similar trend was observed in both digestive gland and gonad of exposed crabs; Vg increased to a lesser extent, although significantly, in hemolymph. Results demonstrated that NP induces Vg synthesis both in male and female mussels, as well as in male crabs. On the basis of the responsiveness of both species investigated, a multi-species approach is indicated in biomonitoring programmes.     

Adaptation strategy of bivalve Modiolus modiolus from upwelling regions of the Kuril Islands shelf (Sea of Okhotsk) to heavy metal effects

Cd, Cu, Fe, Mn, Ni, Pb, Zn concentration in the organs (muscle, gonads, mantle, gills, digestive gland, kidney) of mussel Modiolus modiolus was studied. Mussels were collected from shelf upwelling sites of Kuril Is. Sea of Okhotsk (104 and 85 m) and, for comparison, coastal high contaminated and clean sites (Peter the Great Bay, Sea of Japan). It was found that mussels from shelf upwelling regions accumulated unusually high Cd concentration in studied organs, excepting digestive gland. Shelf mussels have evolved passive adaptation to elevated level of ambient heavy metals (distribution of heavy metal load between all organs, especially, muscle). In contrast, mussels from high contaminated sites have evolved active adaptation (strong regulation of metal concentration in the organs at the maximal permissible concentration due to increased kidney function). We supported that under natural condition, passive adaptation of aquatic organisms to increased ambient metal level have been evolved only under constant low-water temperature.     

Land-air boundary environment as recorded by the18O/16O and13C/12C isotope ratios in the shells of land snails

A yearly cycle of carbon and oxygen isotope composition of shells of the Israeli land snailXeropicta vestalis is presented. The¹⁸O/¹⁶O values indicate that the snails use water from the land-air boundary zone. The¹⁸O/¹⁶O ratio of the shells is in isotopic equilibrium with the water condensate from the vapour during the winter months. During the summer months a contribution to the above water from soil water migrating upwards due to evaporation is noticeable. The δ¹³C values indicate that as in marine molluscs, the carbon isotopic composition in land snails is controlled mainly by the aqueous carbonate compound which is in equilibrium with the land-air boundary CO₂.     

Spatial distributions of δ13C, δ15N and C/N ratios in suspended particulate organic matter of a bay under serious anthropogenic influences: Daya Bay,China

Stable isotopic signatures (δ¹³C and δ¹⁵N) and C/N ratios of suspended particulate organic matter (POM) were investigated from the surface water of Daya Bay during summer and winter of 2015. The relatively high δ¹³C_POM values suggested the input of ¹³C-depleted terrigenous organic matter was low in Daya Bay. There were significant correlations between δ¹³C_POM values and chlorophyll a concentrations both during summer and winter, suggesting the δ¹³C_POM values were mainly controlled by the phytoplankton biomass in the surface water. The distribution of δ¹⁵N_POM values was more complicated than that of δ¹³C_POM and displayed low values in the outer bay and the Dan'ao River estuary. ¹⁵N-depleted ammonia originating from industrial wastewater might have strongly influenced the water quality and stable isotopic signatures of POM near the Dan'ao River estuary. The δ¹³C_POM and δ¹⁵N_POM values strongly reflect the influences of anthropogenic activity and eutrophication in Daya Bay.     

Experimental studies on the accumulation of copper and zinc in the green mussel

Toxicity of copper and zinc to the green mussel, Mytilus viridis was evaluated by short-term bioassays. Probit analysis was used for calculating 48 h median tolerance limits, 95% fiducial limits and slope functions (S). The rates of copper and zinc accumulation were determined by analysing the metal content in the soft parts of the mussels at fixed intervals of time by atomic absorption spectrometry. Bioaccumulation was determined as a function of metal concentration in the experimental medium. The correlations for the regression lines (P < 0.1%) indicate that the uptake of metal is linear at least for the first five weeks. During a more extended experimental period, adjustment to a steady state probably occurs.     

Relationship between13C and18O fractionation and changes in major element composition in a recent calcite-depositing spring — A model of chemical variations with inorganic CaCO3 precipitation

A theoretical model is derived in which isotopic fractionations can be calculated as a function of variations in dissolved carbonate species on CO₂ degassing and calcite precipitation. This model is tested by application to a calcite-depositing spring system near Westerhof, Germany. In agreement with the model,¹³C of the dissolved carbonate species changes systematically along the flow path. The difference in δ values between the upper and lower part of the stream is about 1‰. The¹³C content of the precipitated calcite is different from that expected from the theoretical partitioning. The isotopic composition of the solid CaCO₃ is similar to that of the dissolved carbonate, though in theory it should be isotopically heavier by about 2.4‰. The¹⁸O composition of dissolved carbonate and H₂O is constant along the stream. Calculated calcite-water temperatures differ by about +5°C from the observed temperatures demonstrating isotopic disequilibrium between the water and precipitated solid. This is attributed to kinetic effects during CaCO₃ deposition from a highly supersaturated solution, in which precipitation is faster than equilibration with respect to isotopes.Plant populations in the water have virtually no influence on CO₂ degassing, calcite saturation and isotopic fractionation. Measurements of P_CO2, S_C and¹³C within a diurnal cycle demonstrate that metabolic effects are below the detection limit in a system with a high supply-rate of dissolved carbonate species. The observed variations are due to differences in CO₂ degassing and calcite precipitation, caused by continuously changing hydrodynamic conditions and carbonate nucleation rates.     

Elemental and stable isotope variations of organic matter from a terrestrial sequence containing the Cretaceous/Tertiary boundary at York Canyon,New Mexico

Elemental and isotopic composition of organic matter from a terrestrial sequence including the palynological Cretaceous/Tertiary (K-T) boundary together with an Ir anomaly at York Canyon, New Mexico, record information about paleoclimatological and environmental conditions. Six layers of coal, carbonaceous shale and mudstone with high contents of organic material were selected for analysis. A Late Cretaceous coal bed 10 m below the K-T boundary and an Early Tertiary coal bed containing the K-T iridium anomaly at its base were sampled intensively. In the lower bed, the isotopic ratios¹³C/¹²C,¹⁵N/¹⁴N,andD/H and the elemental ratiosC/N andN/H, all varied sympathetically with one another over depth. In contrast, in the upper coal layer, only theD/H,C/N,andN/H ratios showed some coupling. Immediately above the K-T boundary, theδ¹³C values displayed a long-term shift of 1.8‰ to more negative values, while the hydrogen isotope ratios in these samples did not change significantly. We interpret the covariations in both coal layers as sympathetic responses of the isotopic and elemental ratios to climatic and environmental changes, as have been observed for younger sedimentary organic matter. The long-termδ¹³C shift during the early Tertiary is similar to the trend observed forδ¹³C values of marine carbonates. Our data thus support the proposal that the carbon cycle was perturbed globally by the effects of a drastically decreased marine bioproductivity along the K-T transition. The uncoupling of variations in the climatically sensitive isotopic and elemental ratios seen in the Early Tertiary coal bed provides evidence for major geochemical and environmental changes in the York Canyon area at the end of the Mesozoic. On the other hand, the constancy of δD values in the organic matter deposited at and above the K-T boundary gives no indication of significant changes in the hydrologic/climatic regimes as recorded in theD/H ratios at the site for several thousand years following the event which produced the high Ir concentrations. Our results provide constraints on models that have been advanced to explain that event and its consequences.     

Isotopic lead ages of chondritic meteorites

The isotopic composition of lead was determined for two carbonaceous, two H, and two L chondrites. All are falls. The²⁰⁶Pb/²⁰⁴Pb ratios cover a range from 9.45 to 37.33; the²⁰⁷Pb/²⁰⁴Pb ratios range from 10.39 to 26.10. The isotopic data define a²⁰⁷Pb/²⁰⁶Pb age of 4.635 AE. Uranium and lead concentration data indicate that the isotopic lead ages for the Bruderheim chondrite are concordant within approximately 20%. This contrasts with lead data in the literature for chondrites, which consistently indicate discordant isotopic lead ages due to large excesses of radiogenic lead by factors of two or more. The isotopic lead ages for Pultusk may be concordant; those for a sample of Richardton are not. The lack of concordance for Richardton is not due to the analytical procedures, rather it is likely a result of the handling history of the chondrite prior to analysis.The L-3 chondrite, Mezo-Madaras contains such a high concentration of lead - 5.27 PPM - that accurate ratios for primordial lead can be obtained. These are ²⁰⁶Pb/²⁰⁴Pb= 9.310;²⁰⁷Pb/²⁰⁴Pb= 10.296, values which are in close agreement with a recently reported measurement on lead in troilite from the Canyon Diablo iron meteorite.     

Tracing sewage and natural freshwater input in a Northwest Mediterranean bay: Evidence obtained from isotopic ratios in marine organisms

Elemental carbon and nitrogen levels and isotope ratios were assessed in different biological compartments of a Northwest (NW) Mediterranean bay to trace the various sources of nutrient input from natural (river runoffs) and anthropogenic (harbor outflows, fish farms and urban sewage outfall) sources. Samples from transplanted mussels and natural sea grass communities (Posidonia oceanica leaves and epiphytes) were harvested from different locations throughout the bay during the touristic summer and rainy seasons. The results from the nitrogen analysis revealed that sewage and harbor outflow promote higher nitrogen levels, enrichment of ¹⁵N in the tissues, and a higher seasonal variability in sea grass and epiphytes. In mussel tissues, the δ¹⁵N was also influenced by sewage and harbor outflow, whereas δ¹³C was influenced by terrestrial inputs. These results suggest that natural and anthropogenic nutrient inputs have a temporary and localized influence and affect the sensitivity of natural isotopic ratios to changes in hydrologic conditions, especially to rain and tourism.     

Light carbon isotope events of foraminifera attributed to methane release from gas hydrates on the continental slope,northeastern South China Sea

In 2013, the China Geological Survey and Guangzhou Marine Geological Survey conducted the second Chinese gas hydrate expedition in the northern South China Sea(SCS) and successfully obtained visible gas hydrate samples. Five of the thirteen drilling sites were cored for further research. In this work, Site GMGS2-08 is selected for the stable isotopic analysis of foraminifera present in the boreholes in order to reveal the carbon isotopic characteristics of the foraminifera and their response to methane release in the gas hydrate geological system. Our results show that the methane content at Site GMGS2-08 is extremely high, with headspace methane concentrations up to 39300 μmol L~(-1). The hydrocarbon δ~(13)C values, ranging from-69.4‰ to-72.3‰ PDB, distinctly indicate biogenic generation. Based on the δD analytical results(~(-1)83‰ to~(-1)85‰ SMOW), headspace methane is further discriminated to be microbial gas, derived from CO_2 reduction. By isotopic measurement, five light δ~(13)C events are found in the boreholes from Site GMGS2-08, with foraminiferal δ~(13)C values being apparently lower than the normal variation range found in the glacial-interglacial cycles of the SCS. The δ~(13)C values of benthic Uvigerina peregrina are extremely depleted(as low as~(-1)5.85‰ PDB), while those of planktonic Globigerinoides ruber reach-5.68‰ PDB. Scanning electron micrograph(SEM) studies show that foraminiferal tests have experienced post-depositional alteration, infilled with authigenic carbonate, and the diagenetic mineralization is unlikely to be related to the burial depths. The correlation calculation suggests that the anaerobic oxidation of organic matter has only weak influences on the δ~(13)C composition of benthic foraminifera. This means that the anomalous δ~(13)C depletions are predominantly attributed to the overprinting of secondary carbonates derived from the anaerobic oxidation of methane(AOM). Furthermore, the negative δ~(13)C anomalies, coupled with the positive δ18O anomalies observed at Site GMGS2-08, are most likely the critical pieces of evidence for gas hydrate dissociation in the geological history of the study area.     

Lead concentration and isotopic composition in five peridotite inclusions of probable mantle origin

The lead content of five whole-rock peridotite inclusions (four lherzolites and one harzburgite) in alkali basalt ranges from 82 to 570 ppb (parts per billion). Approximately 30–60 ppb of this amount can be accounted for by analyzed major silicate minerals (olivine ≤ 10 ppb; enstatite 5–28 ppb; chrome diopside ～400 ppb). Through a series of acid leaching experiments, the remainder of the lead is shown to be quite labile and to reside in either glassy or microcrystalline veinlets or accessory mineral phases, such as apatite and mica. The lead isotopic composition of the peridotites (²⁰⁶Pb/²⁰⁴Pb= 18.01–18.90;²⁰⁷Pb/²⁰⁴Pb= 15.52–15.61;²⁰⁸Pb/²⁰⁴Pb= 37.80–38.86) lies within the range of values defined by many modern volcanic rocks and, in particular, is essentially coextensive with the abyssal tholeiite field. In all but one instance, isotopic differences were found between the peridotite and its host alkali basalt. Two of the peridotites clearly demonstrated internal isotopic heterogeneity between leachable and residual fractions that could not simply be due to contamination by the host basalt. However, there is no evidence that these ultramafic rocks form some layer in the mantle with isotopic characteristics fundamentally different from those of the magma sources of volcanic rocks.     

The cytology and occurrence of granulocytomas in mussels

A non-neoplastic inflammatory cellular condition in the marine mussel Mytilus edulis is described and a possible relationship drawn between its incidence and water quality as effected by chronic insult by domestic and industrial waste products. This condition, termed a granulocytoma owing to its dominant constituent cell type, is capable of overcoming host encapsulation and inducing atrophy and autolysis of the digestive gland and may therefore represent a terminal condition.