Comparative petroleum hydrocarbons levels and biochemical responses in mussels from hydrothermal vents (Bathymodiolus azoricus) and coastal environments (Mytilus galloprovincialis)

Aliphatic hydrocarbons and PAHs in the whole soft tissues of Bathymodiolus azoricus from three Mid-Atlantic Ridge hydrothermal vents (Menez-Gwen, Lucky Strike and Rainbow), and Mytilus galloprovincialis from three contaminated coastal sites in South Portugal were analysed, and its effects on the digestive gland microsomes mixed-function oxygenase system (MFO) were assessed.Aliphatic hydrocarbons levels were present in the same magnitude in both coastal and hydrothermal environments, while the UCM (unresolved complex mixture) for coastal mussels were higher than in vent mussels. In general, significantly higher PAHs concentrations were found in coastal mussels, compared to B. azoricus where low molecular weight PAHs (2–3 rings) represented the majority of PAHs contrarily to what was observed in M. galloprovincialis. The MFO components were present in both mussel species, and were detected in vent mussels for the first time. However this system seems to have different roles in species from these contrasting environments. In coastal mussels MFO responded to hydrocarbon contamination while response in hydrothermal organisms appeared to be related mainly to endogenous factors.     

Comparative petroleum hydrocarbons levels and biochemical responses in mussels from hydrothermal vents (Bathymodiolus azoricus) and coastal environments (Mytilus galloprovincialis)

Aliphatic hydrocarbons and PAHs in the whole soft tissues of Bathymodiolus azoricus from three Mid-Atlantic Ridge hydrothermal vents (Menez-Gwen, Lucky Strike and Rainbow), and Mytilus galloprovincialis from three contaminated coastal sites in South Portugal were analysed, and its effects on the digestive gland microsomes mixed-function oxygenase system (MFO) were assessed. Aliphatic hydrocarbons levels were present in the same magnitude in both coastal and hydrothermal environments, while the UCM (unresolved complex mixture) for coastal mussels were higher than in vent mussels. In general, significantly higher PAHs concentrations were found in coastal mussels, compared to B. azoricus where low molecular weight PAHs (2-3 rings) represented the majority of PAHs contrarily to what was observed in M. galloprovincialis. The MFO components were present in both mussel species, and were detected in vent mussels for the first time. However this system seems to have different roles in species from these contrasting environments. In coastal mussels MFO responded to hydrocarbon contamination while response in hydrothermal organisms appeared to be related mainly to endogenous factors.     

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.     

Field validation of antioxidant enzyme biomarkers in mussels (Perna viridis) and clams (Ruditapes philippinarum) transplanted in Hong Kong coastal waters

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.     

The impact of pelagic (Daphnia longispina) and benthic (Dreissena polymorpha) filter feeders on chlorophyll and nutrient concentration

An outdoor experiment testing the effect of water flea (Daphnia longispina) and zebra mussels (Dreissena polymorpha) on physical and chemical water parameters and chlorophyll concentration changes was carried out in 12 containers filled with 150 l of unfiltered water from a lowland reservoir. During the 11 weeks of the experiment, the following physical, chemical and biological measurements were recorded: temperature (°C), oxygen concentration (mg dm⁻³), pH, conductivity (S cm⁻¹), concentration of phosphate phosphorus (PO₄-P) and ammonia nitrogen (NH₄-N) (g dm⁻³), total nitrogen (TN) and total phosphorus (TP) (g dm⁻³), phytoplankton community structure and chlorophyll a concentration (g dm⁻³). The amount of ammonia ions was the highest in the treatment with zooplankton, while phosphate ions reached the highest values in treatments with zebra mussels. The results confirmed the ability of Daphnia to increase the NH₄:PO₄ ratio, whereas excretion from zebra mussels resulted in a decrease in both the N:P ratio (ranging from 9 to 13) and the NH₄:PO₄ ratio in water. In both treatments containing zebra mussels, P-rich water enabled sudden growth of Chlorophyta, resulting in blooms of Hydrodictyon reticulatum after 3–4 weeks of the experiment. Such phenomena were not observed in the control and Daphnia treatments. Our results indicate that zebra mussels, in contrast to Daphnia, may increase the symptoms of water eutrophication and contribute to blooms of expansive phytoplankton species.     

Uptake and depuration of PAHs and chlorinated pesticides by semi-permeable membrane devices (SPMDs) and green-lipped mussels (Perna viridis)

Semi-batch seawater experiments were conducted to follow the uptake and release of selected PAHs (anthracene, fluorathene, pyrene and B[a]P) and organochlorine pesticides (α-HCH, aldrin, dieldrin, p,p′-DDT) in semi-permeable membrane devices (SPMDs) and green-lipped mussels (Perna viridis). Mathematical models were applied to describe the uptake and elimination curves of the contaminants for SPMDs, and kinetic parameters, such as uptake rate constants, and equilibrium triolein/water partitioning coefficients were calculated. SPMD data showed a good fit to estimate rate constant and partition coefficient equations, but only those contaminants which partitioned mainly in the dissolved phase (α-HCH and dieldrin) were well explained for mussels. Poor conformity of the other contaminants indicated mussels uptake by routes other than diffusion, such as ingestion of algae. An apparent equilibrium state was only noted for α-HCH in mussels. Aldrin was not detected in mussels in the first few days of exposure, indicating potential metabolism of this compound. B[a]P was not detected in the triolein of SPMDs, which suggests that the membrane may act as a reservoir. Loss of spiked B[a]P from the triolein was evident in a depuration experiment, which may indicate transfer to the membrane. Rate constants for mussels were higher than those for SPMDs, but the reverse was true for partition coefficients. Overall, mussels and SPMDs had similar uptake rates for all compounds in this study, excluding p,p′-DDT and dieldrin. Contaminant elimination took place more rapidly in mussels, implying that SPMDs are better candidates for detecting episodic discharge of organic contaminants.     

Quality assessment of the blue mussel (Mytilus edulis): Comparison between commercial and wild types

This study compared species identity, microplastics, chemical and microbial contamination between consumption mussels and wild type mussels, collected at Belgian department stores and Belgian groynes and quaysides, respectively. Species identification based on genetic analysis showed a high number of Mytilus (M.) edulis compared to M. galloprovincialis and M. edulis/galloprovincialis hybrid mussels. The number of total microplastics varied from 2.6 to 5.1 fibres/10 g of mussel. A higher prevalence of orange fibres at quaysides is related to fisheries activities. Chemical contamination of polycyclic aromatic hydrocarbons and polychlorobiphenyls could be related to industrial activities and water turbidity, with maximum concentrations at the quayside of port Zeebrugge. The inverse was noted for Escherichia coli contamination, which was relatively low at Zeebrugge quayside with a total count of 3.9 × 10² CFU/100 g tissue, due to limited agricultural effluents. Results of this complementary analysis stress the importance of integrated monitoring and quality assessment.     

Chlorinated compounds and polybrominated diphenyl ethers (PBDEs) in mussels (Mytilus galloprovincialis) collected from Apulia Region coasts

This project was carried out to assess the levels and spatial distribution of organochlorine compounds in the coastal marine environment, using mussels as bioindicators to evaluate the coastal water quality. Levels of polychlorobiphenils (PCB), chlorinated pesticides (DDT isomers, HCH isomers, Aldrin, Dieldrin, alfa-Endosulfan, Hexachlorobenzene, Pentachlorobenzene) and polybrominated diphenyl ethers (PBDEs) were determined in tissues from mussels (Mytilus galloprovincialis) collected along the Apulia Region coasts (Mediterranean Sea). Results indicate that contamination by organochlorine compounds is higher in mussels sampled in the Ionian Sea than in those from the Adriatic Sea, with PCB levels up to seven times higher in mussels from Ionian than from the Adriatic Sea. Although PCB levels were above the maximum values indicated by both European Community (EC) and National regulation in several sample sites, the PCB concentrations were particularly high in some stations, suggesting that these locations require a much specific attention. Conversely, results on the mussel contamination by PBDEs highlight their ubiquitous environmental distribution, and underline the need to establish the maximum level for these compounds in foodstuff, according to European Regulations.     

Relationships between tissue concentrations of chlorinated hydrocarbons (polychlorinated biphenyls and chlorinated pesticides) and antioxidative responses of marine mussels, Perna viridis

Marine mussels, Perna viridis, were transplanted from a reference site to various polluted sites around Hong Kong. After 30 d of exposure, antioxidative responses in the gills and hepatopancreas and tissue concentrations of chlorinated hydrocarbons [polychlorinated biphenyls (PCBs) and chlorinated pesticides (CPs)] were determined for individual mussels. Glutathione S transferase (GST) and glutathione (GSH) were positively correlated with tissue PCB concentrations. Only one of the enzymatic antioxidants, glutathione peroxidase (GPx), showed significant response to tissue PCB. No significant correlation was found between tissue concentrations of chlorinated hydrocarbons and other enzymatic antioxidants (superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and NADPH DT-diaphorase (DT-d). Oxidative stress, measured as thiobarbituric acid reactive substances, was correlated with chlorinated pesticide concentrations in tissues. This study demonstrated a correlation between GST/GSH and chlorinated hydrocarbons. The apparent lack of correlation between trace organic pollutants and some of the enzymatic antioxidants may be due to the inhibitory effects caused by these chemicals. The above results suggest that more investigations are needed before these enzymes can be used as biomarkers.     

Polycyclic aromatic hydrocarbons (PAHs) in transplanted Manila clams (Tapes philippinarum) from the Lagoon of Venice as assessed by PAHs/shell weight index: A preliminary study

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.     

Bioaccumulation depuration kinetics and effects of benzo(a)anthracene on Mytilus galloprovincialis

Polycyclic aromatic hydrocarbons (PAHs) are important environmental pollutants due to their persistence and bioaccumulation potential both in organisms and in sediments. In this study, bioaccumulation and depuration experiments were performed employing local Mediterranean mussel species, Mytilus galloprovincialis, with two biomarkers: filtration rate and lysosomal stability (neutral red retention) assay. Benzo(a)anthracene (BaA) was chosen as the model PAH compound due to its common presence in several matrices in the marine environment. Bioconcentration Factors (BCFs) for the mussels exposed to different BaA concentrations were calculated from both kinetic rate constants and from the experimental data and found between 27-3184 and 16-2745, respectively. Experimental QSAR values were found comparable to the previous QSAR models created for BaA. The effect of BaA exposure on the mussels showed a more clear dose–response relationship according to the results of lysosomal stability compared to the filtration rate.     

Differential piscivory of the native Percichthys trucha and exotic salmonids upon the native forage fish Galaxias maculatus in Patagonian Andean lakes

The present paper analyses predation patterns, of Percichthys trucha and salmonid fish upon Galaxias maculatus in five lakes of northern Patagonia with differing community and environmental characteristics. Tank experiments were performed to evaluate relative efficiency of native and exotic predators of G. maculatus under treatments with and without cover (aquatic vegetation). Important differences were found between predators with regards to distribution and consumption of G. maculatus. Salmonids are more efficient than P. trucha in consuming G. maculatus in deep environments with scarcely vegetation; in contrast to native species they frequently use the pelagic environment. Although pelagic habitat might have served in the past as a refuge from native predators in the past, G maculatus now experiences intense predation in the pelagic zone by exotic salmonids. It is suggested that the widespread distribution of G. maculatus in Patagonian lakes may have facilitated the success of salmonids throughout Patagonia.     

Cloning and developmental expression of kinesin superfamily7 (kif7) in the brackish medaka (Oryzias melastigma), a close relative of the Japanese medaka (Oryzias latipes)

kif7 is a member of the kinesin superfamily members which are molecular motor proteins that move along microtubules in a highly regulated manner through ATP hydrolysis. In this paper, we report on the cloning of the Oryzias melastigma kif7 (omkif7) using primers designed according to the Japanese medaka (Oryzias latipes) database. The cloned omkif7 has an open reading frame of 3762bp and is deduced to encode a polypeptide of 1254 amino acids that possesses the putative ATP-binding and microtubule-binding motifs in its motor domain at the N-terminal region. We characterized the cloned omkif7 by comparison with the zebrafish kif7. Both omkif7 and zebrafish kif7 are shown to be expressed in all embryonic stages and adult tissues examined with higher expression level in the testis and ovary. Whole-mount in situ hybridization revealed that the expression of omkif7 is ubiquitous during the early stages of embryonic development, but became more restrictive and localized to the brain, fin bud and eye at later development. This study suggested that the brackish O.melastigma can serve as a good seawater model organism for developmental studies by utilizing the resources developed from its close relative of the Japanese medaka.     

First evidence of fiberglass ingestion by a marine invertebrate (Mytilus galloprovincialis L.) in a N.W. Mediterranean estuary

Alfacs Bay is a N.W. Mediterranean estuary important for mussel (Mytilus galloprovincialis) aquaculture. During studies at the site, fiberglass particles were detected. The presence of fiberglass occurred naturally in the water throughout the study period (November 2006 to July 2007). An investigation was undertaken into its role in the feeding behavior of the local mussels. Fiberglass was present in all types of mussel samples. Rejection, which we would have expected for the whole study period, was only evident during the second season studied. To our knowledge, this is the first report of the ingestion of fiberglass by a marine organism. Our novel finding indicates the need to investigate fiberglass ingestion by marine organisms at different levels of the food web and the possible implications for human health and the health of the organisms themselves. In addition, we propose the use of mussels as sentinel organisms to monitor fiberglass contamination in marine ecosystems.     

微囊藻(FACHB-905)和鱼腥藻(FACHB-82)响应温度变化的功能特性权衡

微囊藻和鱼腥藻是水华蓝藻的两个主要类群,两种藻均可调节自身形态及生理特性来维持快速生长,这也是两个类群蓝藻水华维持的基础.本研究分析了微囊藻(FACHB-905)和鱼腥藻(FACHB-82)生长、形态及叶绿素荧光参数对温度变化的响应,以及生长与特性间的权衡关系.结果显示:该微囊藻细胞直径随温度升高而降低,但是比增长速率维持稳定,表明在高温条件下,其可能通过减小细胞大小的方式维持比增长速率;该鱼腥藻在不同温度下,平均细胞直径和藻丝长度呈现显著变化,高温条件下,其维持较高的比增长速率,但是细胞直径增大,藻丝长度缩短,这可能是其调节自身形态以维持较高比增长速率的方式.该微囊藻和鱼腥藻分别在细胞较大和较小时,藻细胞潜在的光化学效率更高.本研究表明这两种蓝藻可以通过权衡藻细胞形态、生理特性两者与生长速率之间的关系来适应温度的变化以达到自身最佳的生长状态,微囊藻(FACHB-905)通过调节细胞大小和光合活性来维持生长优势,而鱼腥藻(FACHB-82)则通过细胞大小、藻丝长度和光合活性的调节来维持生长优势.本研究的结果有助于提升对于水华蓝藻生长维持机制的认识.     

TBT toxicity on the marine microalga Nannochloropsis oculata

Commercial antifouling formulations containing TBT are the major source of organotin contamination in coastal waters. In view of the persisting TBT residues (13 ng Sn l⁻¹) in the coastal waters of South Korea, an attempt has been made to evaluate the growth response and biochemical composition of laboratory-cultured Nannochloropsis oculata to TBT toxicity. It is evident that the persisting concentration level of TBT is high enough to cause adverse effect on the microalgal species. The EC₅₀ (24 h) was found to be at 0.89 nM level of TBT for this marine eustigmatophyte N. oculata. Photosynthetic pigment content was significantly affected. At elevated TBT concentrations of 1.0 nM, especially pronounced changes in biochemical composition was found. TBT tolerance of N. oculata and its growth as well as biochemical responses are discussed.     

沉水植物苦草(Vallisneria natans)对多环芳烃污染沉积物的修复作用

沉水植物是浅水湖泊生态系统的关键种群,对水环境质量及水生生态系统结构有重要影响.以东太湖大水港和湖湾区2个典型的具有不同污染程度的沉水植物苦草(Vallisneria natans)生长区域为研究对象,考察苦草对多环芳烃(PAHs)的修复效果.结果表明,经过34 d植物修复试验,重度污染的东太湖大水港沉积物中PAHs的去除率为62%,沉积物中PAHs降解速率为0.024 d-1;而中度污染的东太湖湖湾区沉积物的PAHs去除率为42%,其降解速率为0.015 d~(-1).种植苦草的沉积物中PAHs的降解速率是未种植苦草的降解速率的2~3倍.苦草对沉积物中高分子量PAHs的修复效果尤为显著.因此,苦草可以有效地用于PAHs污染沉积物的修复,尤其是在重污染和高分子量PAHs污染沉积物中,苦草的修复作用更加明显.     

水深对沉水植物苦草(Vallisneria natans)和穗花狐尾藻(Myriophyllum spicatum)生长的影响

水深是影响浅水湖泊沉水植物生长的主要因素之一.莲座型苦草（Vallisneria natans）和冠层型穗花狐尾藻（Myriophyllum spicatum）是我国长江中下游浅水湖泊中常见的沉水植物种类,二者在形态特征上具有较大的差异.在自然水体中,水深变化对这两种植物的生长以及竞争格局的影响还有待研究.本文设计了3个水深梯度（水深0.5、1.5、2.5 m）,探讨混栽条件下苦草和穗花狐尾藻生长和竞争格局对水深变化的响应.结果显示在实验系统内,中水深（1.5 m）处理组对两种植物的生长均最有利,表现为两种植物的相对生长率和生物量均最高.低水深（0.5 m）处理组苦草的生物量和相对生长率均显著低于高水深（2.5 m）处理组;穗花狐尾藻则相反,高水深对其生长的抑制作用更大.2种沉水植物在高水深胁迫时均表现出地上部分（叶长或茎长）增加,地下部分（根长）减少的形态响应特征.此外,随着水深由高到低,苦草与穗花狐尾藻生物量之比逐渐减小,表明苦草在两种植物中的竞争优势逐渐降低.研究表明湖泊水深变化不仅能够影响沉水植物的丰度,同时还可能会影响沉水植物的群落结构,而在我国浅水湖泊的生态修复实践中,在通过水位调控恢复沉水植物时,调控范围应考虑目标植物（如苦草）的光合特征.     

中国鱼腥藻属的两个新记录种

迄今为止,全球范围共报道出100多种鱼腥藻,中国记录报道的仅有50余种,但有些种类的描述仍较模糊.最近在福建、浙江等地进行野外调查时,发现了多种丝状蓝藻.其中就有2种鱼腥藻在中国尚未报道:威格鱼腥藻(Anabaenaviguieri Denis et Frémy 1923)和史密斯鱼腥藻(Anabaena smithii(Komárek)Watanabe 1992).