Petroleum-related hydrocarbons in deep and subsurface sediments from South-Western Barents Sea

Subsurface sediments from a pockmark area in South-Western Barents Sea have been earlier found to contain elevated levels of petroleum-related polycyclic aromatic hydrocarbons. This work describes a comprehensive analysis of various biomarkers, including the highly source-specific hopanes, in a 4.5?m long gravity core from the same area, together with subsurface sediment samples from other areas in the region without pockmarks present ("background samples"). A clear difference between the pockmark gravity core and the background sediment cores was found, both with regard to genesis and the level of transformation of organic matter. A number of indicator parameters, such as methylphenanthrene index (MPI-1), point towards a significantly higher maturity of hydrocarbons in the pockmark core throughout its length as compared to the other sampled locations. Higher contents of microbial hopanoids (hopenes) may indicate the former presence of petroleum. These findings confirm the hypothesis of a natural hydrocarbon source in the deeper strata present in the studied location with pockmarks.     

Physical and biological response of the Arabian Sea to tropical cyclone Phyan and its implications

The response to the tropical cyclone Phyan, which developed in the eastern Arabian Sea during 9-11 November 2009, was rapid cooling of sea surface temperature (SST), enhancement of chlorophyll a and two-fold increase in net primary productivity (NPP). Cooling of SST was immediate in response to the strong wind-mixing, and the subsequent upward Ekman pumping sustained the cooling even after the dissipation of Phyan. The biological response mediated by the upward Ekman pumping driven vertical transport of subsurface nutrient showed a time lag of 3-4 days. The CO? flux to the atmosphere associated with Phyan was 0.123 Tg C, which accounted for ~85% of the total out-gassing from the eastern Arabian Sea during November. Thus, an increased occurrence of cyclones in a warming environment will lead to an enhanced biomass production and also increase in CO? out-gassing.     

赤道太平洋的环流

一.引 言 赤道太平洋上层海洋环流的主要特征已被建立十多年了。1942年斯维尔德鲁普等人描述了中太平洋的表面流:往西流的北和南赤道流以及往东流的北赤道逆流。随后,南赤道逆流也被用表面动力高度图表示出来(Reia,1961),Cromwell等人(1954)发现了赤道潜流,从而对上述环流的描述进行了主要修正。Hisard和Rual(1970)发现了赤道潜流下面     

五种植物提取液的抗鱼病菌和抗鱼病毒效应(英文)

本文旨在探索用廉价的野生植物防治鱼病。所用的植物有牛繁缕(Stellaria aqu-atica),双花凤仙(Impatiens biflora),夜来香(Oenothera biennis),艾草(Artem-isia vulgaris)和忍冬(Lonicera japonica)。用作试验的鱼病菌共13种(18个菌株),分属于气单孢菌属、假单孢菌属、爱德华氏菌属、耶尔森氏菌属、弧菌属。所用的鱼病毒为传染性胰脏坏死病毒IPNV,传染性造血组织坏死病毒IHNV。上述病原微生物均获自美国马里兰大学微生物系。实验结果表明,五种植物提取液均有不同程度的抗鱼病菌作用,其中以牛繁缕的抗菌谱最广,作用力最强。忍冬、艾草、牛繁缕有抗鱼病毒作用。其中以忍冬的效果最好,它能抑制IPNV和IHNV。而艾草和牛繁缕只能抑制IHNV。     

Evaluating the effects of protection on fish predators and sea urchins in shallow artificial rocky habitats: a case study in the northern Adriatic Sea

Man-made defence structures (e.g., breakwaters, jetties) are becoming common features of marine coastal landscapes all around the world. The ecology of assemblages of species associated with such artificial structures is, however, poorly known. In this study, we evaluated the density and size of fish predators of echinoids (i.e., Diplodus sargus, Diplodus vulgaris, Sparus aurata), and the density of sea urchins (i.e., Paracentrotus lividus) at defence structures (i.e., breakwaters) inside and outside the marine protected area of Miramare (northern Adriatic Sea) in order to: (1) assess possible differences in fish predator density and size between protected and fished breakwaters; (2) assess whether fish predation may have the potential to affect sea urchin density in artificial rocky habitats. Surveys were carried out at four random times over a period of two years. Total density, and density of medium- and large-sized individuals of the three predatory fishes were generally greater at the protected than at the fished breakwaters, whereas no differences were detected in the density of small-sized individuals. Density of the sea urchin P. lividus did not show any difference between protected and fished breakwaters. The results of this study suggest that: (1) protection may significantly affect predatory fishes in artificial rocky habitats; (2) differences in predatory fish density, and size may be unrelated with the density of the sea urchin P. lividus; (3) protected artificial structures such as breakwaters, originally planned for other purposes, could represent a potential tool for fish population recovery and enhancement of local fisheries.     

Total content and chemical speciation of arsenic in the polychaete Sabella spallanzanii

An unusual feature has been observed in polychaetes regarding their capacity to accumulate high levels of relatively toxic forms of arsenic in specific tissues. Basal levels of arsenic and distribution of its compounds were investigated in tissues of the Mediterranean polychaete Sabella spallanzanii. Particularly high concentrations were measured in the branchial crown (1036+/-136 microg/g d.w.) and chemical speciation revealed that the predominant form was the relatively toxic dimethylarsinate (DMA). These data suggest a potential role of As as anti-predatory strategy in polychaetes.     

Analysis of medaka cytochrome P450 3A homotropic and heterotropic cooperativity

We have previously demonstrated that medaka CYP3A is associated with metabolism of several endobiotics including steroids and bile acids. In this study, we demonstrate that medaka CYP3A catalysis exhibits unusual kinetic behaviors consistent with allosteric interaction which cannot be described by hyperbolic kinetic models. Using 7-benzyloxy-4-(trifluoromethyl)-coumarin (BFC) and nonylphenol as CYP3A substrates, we describe both homotropic and heterotropic cooperative interactions. Given the role of CYP3A in maintaining the homeostatic balance for numerous endobiotics, enzymatic activation/inhibition by endocrine disruptors (EDCs) represents a putative (non-genomic) mechanism for endocrine disruption.     

Evidence from heterologous expression of glutathione S-transferases A and A1 of the plaice (Pleuronectes platessa) that their endogenous role is in detoxification of lipid peroxidation products

cDNA clones for glutathione S-transferases A (GST-A) and A1 (GST-A1) from plaice (Pleuronectes platessa) were expressed as N-terminally 6XHis tagged proteins in Escherichia coli and purified to homogeneity from Ni-NTA silica. GST-A was an efficient catalyst for conjugation of unsaturated alkenals derived from peroxidation of polyunsaturated fatty acids with the highest activity observed with trans-non-2-enal (8 micromol min(-1) mg(-1)). GST-A1 was a very efficient Se-independent glutathione peroxidase with an activity towards cumene hydroperoxide of 25 micromol min(-1) mg(-1). Although the enzymes exhibited moderately high activities towards the model substrate 1-chloro-2,4-dinitrobenzene (CDNB) they exhibited little or no activity towards other common prototypical xenobiotic substrates. Together with data for ontogeny, tissue distribution and inducibility of these enzymes, we contend that a primary function of these enzymes is protection from the harmful effects of lipid peroxidation products generated naturally or exacerbated by xenobiotic exposure.     

Oxidative stress in ecotoxicology: from the analysis of individual antioxidants to a more integrated approach

An integrate approach will be discussed for investigations on oxidative stress in xenobiotic toxicity. While the analysis of individual antioxidants is useful for their sensitivity and to understand the mode of action of a stressor, the integration with the analysis of the total antioxidant capacity provides a more holistic assessment of the overall biological significance of such variations. TOSC has a greater predictive value on the health condition of the organisms and allows to discriminate the different role of specific ROS in oxidative stress syndrome.