Accumulation of Zn,Cu and Cd by crabs and barnacles

The crab Carcinus maenas (L.) and the barnacle Elminius modestus Darwin were exposed to a range of dissolved concentrations of Zn, Cu and Cd for 21 days in artificial seawater. Accumulation of Zn and Cu by crabs has been interpreted in terms of the presence of a regulation mechanism to maintain constant body concentrations (83·2 ± 19·4 μg Zn g^?1 dry wt.; 39·8 ± 9·8 μg Cu g^?1 dry wt.) under varying external dissolved metal levels, until a threshold dissolved metal concentration (c. 400 μg Zn l^?1; c. 170 μg Cu l^?1) beyond which net accumulation of metal begins. Cadium appears to be accumulated by C. maenas at all exposures with no evidence for regulation of body cadmium concentrations. Exposure of E. modestus to Zn, Cu or Cd caused net accumulation of the respective metal in the bodies of the barnacles, with no evidence for regulation of body metal concentrations.     

Inhibition of coral fertilisation and larval metamorphosis by tributyltin and copper

Fertilisation and larval metamorphosis of reef-building corals are important life history events leading to recruitment of juvenile corals to reef populations. Little is known of the sensitivity of these early life phases to pollution, or their relative susceptibility to certain toxicants compared with established coral colonies. Inhibition of fertilisation and larval metamorphosis of the coral Acropora millepora (Ehrenberg, 1834) was assessed in response to solutions of the antifoulants tributyltin (TBT) and copper (Cu) using laboratory-based bioassays. Nominal concentrations that inhibited 50% fertilisation and metamorphosis (IC50) were calculated from 4 h fertilisation and 24 h metamorphosis assays and were based on introduced dose. Cu was most potent towards fertilisation with an IC50 of 17.4 micrograms/l. TBT however, proved more toxic to larval metamorphosis having an IC50 of 2.0 micrograms/l. Inert surfaces coated with either Cu- or TBT-based antifouling paint also inhibited fertilisation and metamorphosis. The degree of inhibition was correlated with surface area of the paint coating. These results indicate fertilisation and metamorphosis of coral can be sensitive to active components of antifouling paints.     

厦门港湾蟹类的分布

本文根据我所1980年8月至1981年10月厦门港湾海洋环境综合调查,选取其季度月(11,2,5,8月)资料,研究该港湾蟹类的种类组成、数量分布与季节变化。     

Hitching a ride on a hermit crabs home: Movement of gastropod shells inhabited by hermit crabs

There is little information on the movement and connectivity patterns for many species. The movement by shells occupied by the hermit crab Pagurus bernhardus and the organisms encrusting these shells was investigated on the south coast of Wales (UK). Hermit crabs shells moved considerable distances along the shore over 1 month periods, moving a minimum mean distance (±SE) of 148 (±8) and 174 (±9) m from release sites in the January and August respectively. Hermit crab-inhabited shells were also found to travel across habitats (sandy areas) that are unsuitable for both hermit crabs and epibionts. Through the examination of 150 of the most abundant shells used by P. bernhardus (Nucella lapillus), twelve epibiont species were found (10 animal and 2 algal species) and choice experiments demonstrated that hermit crabs preferred epibiont covered shells (84%), compared with bare shells (16%). The distance that shells were moved and the preference of hermit crabs for epibiont encrusted shells, coupled with the ability for epibionts to cross unsuitable habitats, may provide a dispersal advantage for epibiont species.     

Expression of P-glycoprotein in southeastern oysters, Crassostrea virginica

These studies provide important fundamental information regarding the expression of P-glycoprotein (p-gp) in southeastern oysters (Crassostrea virginica). Using rhodamine transport studies, p-gp activity was detected in newly fertilized embryos. A monoclonal antibody (C219) was used to evaluate p-gp expression in oyster tissues. On the basis of laboratory studies, p-gp expression tended to be higher in gill tissues than mantle tissues, and was generally not related to salinity differences. Seasonal studies were conducted with oysters collected monthly for 1 year from Lighthouse Creek, an unpolluted site. There was a general pattern of higher p-gp expression in the warmer months and lower expression in the colder months. In contrast, total gill protein concentrations decreased during the warmer months and increased during the colder months. These studies indicate that there are seasonal patterns in p-gp expression which may represent an adaptive response to natural stressors associated with summer conditions.     

Tributyltin compounds in mussels,oysters and sediments of Chinhae Bay,Korea

To study the historical and current status of the environmental levels of organotin compounds in Chinhae Bay in southeast Korea, mussels (Mytilus edulis galloprovincialis), oysters (Crassostrea gigas) and sediment cores were analysed for tributyltin (TBT) compounds. TBT concentrations were higher in oysters (mean: 0.25 μg TBT-Sn/g dry wt) than in mussels (mean: 0.20 μg TBT-Sn/g dry wt). The major sources of TBT are in the inner bay, and the highest TBT concentrations of 0.50 μg TBT-Sn/g (mussels) and 0.74 μg TBT-Sn/g (oysters) were observed at the site adjacent to the port. Concentrations of TBT decreased sharply with distance from the inner bay toward the outer bay and there was little TBT in the outer bay. A significant correlation was observed between this distance and the tissue TBT content of oysters and mussels. The concentration and percentages of TBT in sediment cores decreased with depth as a result of debutylation. Half-lives of TBT and dibutyltin (DBT) in sediments were 6.9 and 11.6 y, respectively. The TBT concentrations in mussels were higher than those in sediments by a factor of 4–7.     

Domoic acid excretion in dungeness crabs, razor clams and mussels

Domoic acid (DA) is a neurotoxic amino acid produced by several marine algal species of the Pseudo-nitzschia (PN) genus. We studied the elimination of DA from hemolymph after intravascular (IV) injection in razor clams (Siliqua patula), mussels (Mytilus edulis) and Dungeness crabs (Cancer magister). Crabs were also injected with two other organic acids, dichloroacetic acid (DCAA) and kainic acid (KA). For IV dosing, hemolymph was repetitively sampled and DA concentrations measured by HPLC-UV. Toxicokinetic analysis of DA in crabs suggested most of the injected dose remained within hemolymph compartment with little extravascular distribution. This observation is in sharp contrast to results obtained from clams and mussels which exhibited similarly large apparent volumes of distribution despite large differences in overall clearance. These findings suggest fundamentally different storage and elimination processes are occurring for DA between bivalves and crabs.     

Genotoxic, cytotoxic and developmental effects of tributyltin oxide (TBTO): an integrated approach to the evaluation of the relative sensitivities of two marine species.

Adopting an integrated approach the potential genotoxic, cytotoxic and developmental effects of tributyltin oxide (TBTO), a known endocrine-disrupting agent for neogastropods, have been evaluated in two ecologically relevant invertebrates: Mytilus edulis (blue mussel) and Platynereis dumerilli (rag worm). Following determination of the maximum tolerated dose (MTD) in terms of developmental and survival effects, the embryo-larval stages of these organisms were exposed to a range of concentrations of TBTO, and analysed for cytotoxic (proliferation rate index) and genotoxic (sister chromatid exchanges and chromosomal aberrations) effects. The study suggested that: (1) TBTO is both toxic and genotoxic to embryo-larval stages of both species; (2) at comparable concentrations, for developmental and genotoxic effects, P. dumerilii (non-target species) is more sensitive compared to M. edulis (target species); and (3) genotoxic effects are more closely tied with the development and survival of the organisms. The study emphasises the need of the evaluation of genotoxic potential of other endocrine-disrupting agents in different taxonomic groups.     

Cellular responses of oysters, Crassostrea virginica, to metal-contaminated sediments

Elevation of metal concentrations in coastal environments associated with anthropogenic enrichment pose a significant threat to estuarine organisms. The purpose of this study was to evaluate the relationships between cellular responses that may be potentially valuable as indicators of chronic stress and metal-contaminated sediments. For these studies, hatchery-reared juvenile oysters were deployed in situ at 15 sites for approximately 1 month around Charleston Harbor, SC. The effects on lysosomal destabilization and glutathione concentrations were determined; and the relationships between the cellular responses and sediment metal concentrations were described. Both single metal and multiple metal parameters (based on total metal concentrations, aluminum normalizations, and summed sediment quality guidelines) were considered. Generally, significant correlations were observed for individual metal analytes and multiple metal parameters. Since many of the individual metal analytes covary, the responses may reflect overall contaminant loading rather than responses to individual metals. Methods for estimating overall contaminant loading based on multiple analytes provide a more realistic estimate of potential adverse effects.     

An unexploited population of oysters,Ostrea lutaria Hutton,from foveaux strait

Settlement of Ostrea lutaria on sand‐cement‐plastered asbestos plates held in steel frames on the bottom of Foveaux Strait was studied from March 1965 to April 1967. Spat mortality over the period of plate exposure (about one month) was very low (maximum of 3 percent) and was greatest shortly after settlement. There was no evidence that mortality was due to predation. Essentially the same seasonal pattern of settlement was observed each year. Eighty to 90 percent of spat settled between mid December and mid February in both summers; settlement occurred as early as October; some was observed as late as July.

Results of field experiments suggest some very tentative conclusions on the settlement behaviour of O. lutaria: (1) The larvae are benthopelagic and remain on the bottom in strong current conditions. (2) Light stimulates swimming of larvae in still water. (3) In still water and low light intensities of the area larvae tend to swim upward toward the light. (4) In still water and dim light of the area larvae settle predominantly on under surfaces. (5) In still water in the absence of light larvae settle predominantly on upper surfaces. (6) Under the conditions of current and light in the multiplate frames used to sample spatfall here, larvae settle mainly on upper surfaces. (7) Larvae tend to crawl up inclined surfaces before settling.

The results indicate that larval behaviour may be changed by small alterations of light intensity and current. The contradictory nature of surface angle preferences found by other workers for various species of Ostrea and Crassostrea may have been due to such small variations caused by the experimental techniques. It is possible that the settlement behaviour of all species of these genera is similar.     

Acute toxicity of heavy metals, tributyltin, ammonia and polycyclic aromatic hydrocarbons to benthic amphipodgrandidierella japonica

Benthic amphipod,Grandidierella japonica widely inhabits the Korean coastal waters and is developed as a standard test species for sediment toxicity tests. We exposedG . japonica to various pollutants including 4 kinds of inorganic metals (Ag, Cd, Cu and Hg), tributyltin [TBT], ammonia and 7 polycyclic aromatic hydrocarbon (PAH) compounds (acenaphthene, chrysene, fluoranthene, fluorene, naphthalene, phenanthrene and pyrene) to estimate the no observed effect concentration (NOEC) and the median lethal concentration (LC50) of each pollutant during the 96-hour acute exposure. Among all tested pollutants, TBT was most toxic toG. japonica, and Hg was most toxic among inorganic metals. The toxicity of pyrene toG. japonica was greatest among PAH compounds, followed by fluoranthene, phenanathrene, acenaphthene, fluorene and naphthalene. The toxicity of PAH compounds was closely related to their physico-chemical characteristics such as K_ow and water solubility.G. japonica responded adequately to pollutant concentrations and exposure durations, and the sensitivity ofG. japonica to various inorganic and organic pollutants was generally comparable to other amphipods used as standard test species in ecotoxicological studies, indicating this species can be applied in the assessment of environments polluted by various harmful substances.     

Uptake and transformation of C-labelled tributyltin chloride by the dog-whelk, nucella lapillus: Importance of absorption from the diet

The importance of the diet as a source of tributyltin (TBT) in Nucella lapillus was studied using [¹⁴C]tributyltin chloride. In N. lapillus provided with prelabelled mussels, Mytilus edulis, in labelled water (mean 20·5 ng/litre TBT) the rate of accumulation of total ¹⁴C was 2–3 times that in unfed animals. Owing to its degradation in the tissues of both fed and unfed animals, concentrations of [¹⁴C]TBT tended to reach a plateau after only 28 days. However, total concentrations of ¹⁴C were still increasing after 49 days. Under experimental conditions (15°C, ample food, no disturbance) the diet accounted for about 50% of the body burden of TBT in N. lapillus after 49 days exposure: concentration factors (dry tissue/water) for [¹⁴C]TBT in both male and female N. lapillus were similar at about 60 000 in fed and 30 000 in unfed animals. It is concluded that the diet may contribute less than half of the body burden of TBT found in natural populations subjected to life-long exposure.     

几种化学物质对两种牡蛎幼虫附着和变态的诱导

本文研究5种神经递质和1种神经肽对两种牡蛎幼虫附着和变态的诱导效应。结果表明：L－多巴对牡蛎幼虫附着行为的诱导快速而有效，浓度10μmol/dm^3，2h内有附着行为的幼虫约占50％，并使之正常变态，肾上腺素、去甲肾上腺素和L－多巴均能有效地诱导两种牡蛎幼虫变态，它们的最适诱导浓度分别为50、50和5μmol/dm^3，诱导变态率分别达97．1％、90．6％和70．5％（长牡蛎），74．9％、74．3％和37．2％（僧帽牡蛎）；多巴胺的诱导变态效果不显著，而γ－氨基丁酸和5－羟色胺不能有效诱导变态。两种牡蛎幼虫对上述有效诱导药物的反应，长牡蛎优于僧帽牡蛎。肾上腺素诱导长牡蛎，最适处理时机在眼点幼虫后期，持续处理时间为2h之内。     

Long-term effects of tributyltin compounds on the baltic amphipod, Gammarus oceanicus

Amphipod larvae, Gammarus oceanicus, were exposed for 8 weeks to bis(tributyltin) oxide (TBTO) or tributyltin fluoride (TBTF), or for 5 weeks to leachates from tributyltin-containing antibiofouling paints. No larvae survived 8 weeks' exposure to 3 μg/litre TBTO or TBTF. Differential larval survival occurred during exposure to 0·3 gmg/litre of these same compounds. Paint leachates were shown to cause similar toxicity responses at comparable aqueous tributyltin concentrations. An examination of sublethal responses showed slight decreases in growth for larvae exposed to TBTO and to paint leachates, although responses at tributyltin levels below 1 μg/litre were not marked. Whole-animal oxygen consumption rates were not affected by low tributyltin exposure levels. While these studies demonstrate low level toxicity of tributyltins, effects on oxygen consumption and growth do not indicate a mode of action for these compounds.     

Facilitative effects of introduced Pacific oysters on native macroalgae are limited by a secondary invader,the seaweed Sargassum muticum

Introduced habitat-providing organisms such as epibenthic bivalves may facilitate the invasion and expansion of further non-native species which may modify the effects of the primary invader on the native system. In the sedimentary intertidal Wadden Sea (south-eastern North Sea) introduced Pacific oysters (Crassostrea gigas) have overgrown native blue mussel beds (Mytilus edulis). These oyster beds are now providing the major attachment substratum for macroalgae. Recently, oysters have expanded their distribution into the shallow subtidal zone of the Wadden Sea, and there support a rich associated species community including the Japanese seaweed Sargassum muticum, which has been presumably introduced together with the oysters. With a block designed field experiment, we explored the effects of S. muticum on the associated community of soft-bottom C. gigas beds in the shallow subtidal. Replicated oyster plots of 1 m² were arranged with a density of 0, 7, 15 or 45 S. muticum m^? 2, respectively. We found no effects of different S. muticum densities on associated epi- and endobenthic community compositions associated to the oyster plots. However, the overall coverage of sessile organisms settling on the oyster shells was significantly reduced at high S. muticum densities. The occurrence of abundant native macro-algal species such as Polysiphonia nigrescens, Antithamnion plumula and Elachista fucicola decreased with increasing S. muticum densities. Sessile invertebrates, by contrast, were only marginally affected and we found no effects of S. muticum canopy on diversity and abundance of endofauna organisms. We conclude that increasing densities of S. muticum on C. gigas beds in the shallow subtidal zone of the Wadden Sea limit the occurrence of native macroalgae which otherwise would benefit from the additional hard substratum provided by the oysters. Thus, a secondary invader may abolish the effects of the primary invader for native species by occupying the new formed niche.     

The effects of glutathione depletion on reproductive success in oysters, Crassostrea virginica.

Glutathione (GSH) is a ubiquitous tripeptide that functions as a very important modulator of cellular homeostasis, including detoxification of metals and oxyradicals. Therefore, depletion of GSH may predispose organisms to pollutant stress. Reproductively active oysters (Crassostrea virginica) were exposed to buthionine sulfoximine in the laboratory to deplete gonadal GSH. The effects of metal exposures (Cd and Cu) on fertilization and developmental assays were evaluated using gametes from control and GSH-depleted adults. Fertilization success was not affected by GSH status, i.e. the fertilization rates of gametes derived from GSH-depleted adults were the same or slightly higher. However, GSH depletion did increase the susceptibility of developing embryos to metal toxicity, i.e. adverse effects on embryonic development were observed at lower metal concentrations with gametes derived from GSH-depleted adults. These effects may be related to diminished removal of free radicals or increased availability of metals. Whereas sperm penetration of embryonic membranes and fertilization success may be facilitated by free radicals, the persistence of free radicals during subsequent developmental periods may adversely affect differentiation and normal development. GSH probably also plays an important role in scavenging toxic metals and reducing metal interactions with essential developmental processes. These results suggest that parental depletion of GSH may increase the susceptibility of embryos to metal toxicity.     

广西茅尾海常见牡蛎的分子鉴定

应用COⅠ条形码技术鉴定广西茅尾海的3种常见牡蛎,其俗名分别是"白眼蚝"、"红眼蚝"和"蚝砺"。研究结果表明,茅尾海3种牡蛎应归属牡蛎科(Ostreidae)、巨蛎属(Crassostrea),其中"白眼蚝"是香港巨牡蛎(C.hongkongensis)、"红眼蚝"是有明巨牡蛎(C.ariakensis)、"蚝砺"是Kumamoto牡蛎(C.sikamea)。研究验证了已开发的多重PCR技术能对3种牡蛎进行快速鉴定,并揭示香港巨牡蛎是茅尾海优势种,基本上澄清了与"近江牡蛎"相关的俗名问题。