Oxidative stress in two populations of killifish (Fundulus heteroclitus) with differing contaminant exposure histories     

Bacanskas LR  Whitaker J  Di Giulio RT 《Marine environmental research》2004,58(2-5):597-601

A population of killifish (Fundulus heteroclitus) inhabiting a creosote-polluted inlet of the Elizabeth River demonstrates tolerance to the acute toxic effects exerted by contaminated sediments on reference site killifish. Previous data have suggested that upregulated antioxidant defenses contribute to short-term tolerance in killifish exposed to Elizabeth River sediments. This study investigated population differences in antioxidant defenses from wild caught Elizabeth River and reference population killifish in different seasons, and after being held in the laboratory. Parameters measured in the killifish were total glutathione concentrations (GSH(T)), activities of glutathione reductase (GR), glutathione peroxidase (GPx), and lipid peroxidation (LPO), all in adult hepatic tissues. The Elizabeth River population exhibited greater GSH(T), higher GPx activities, and increased LPO as compared to the reference population. Sex specific population differences were also observed in GSH(T) and GPx. Both populations displayed decreased GSH(T) and increased GR from early to late summer, as well as after being held in the laboratory. This study indicates that there are many factors that may contribute to differences in levels of antioxidant defenses in addition to exposure to contaminants, including reproductive status and environmental conditions.  相似文献   

Mineralogical and geochemical features of authigenic carbonates on seepings and hydrothermal fields (By the examples of the Black Sea reefs and the mounds of the lost city field)     

A. Yu. Lein  O. Yu. Bogdanova  Yu. A. Bogdanov  L. I. Magazina 《Oceanology》2007,47(4):537-553

Two genetically different types of authigenic carbonate mounds are studied: those within an active hydrothermal field related to serpentinite protrusions in the zone of intersection of a transform fracture zone and the Mid-Atlantic Ridge, and those in an active field of methane seepings in the Dnieper canyon of the Black sea. The general geochemical conditions under which authigenic carbonate formation occurs in the two fields considered were found. They include the presence of reduced H₂S, H₂, and CH₄ gases at the absence of free oxygen; the high alkalinity of the waters participating in the carbonate formation; the similarity of the textural and structural features of authigenic aragonite, which represents the initial mineral of the carbonate matter of the mounds; the paragenesis of aragonite with sulfide minerals; and the close relation of carbonate mounds with communities of sulfate-reducing and methane-oxidizing microorganisms. A new mechanism of formation of hydrothermal authigenic carbonates is suggested; it implies their microbial sulfate reduction over the hydrogen of the fluid in the subsurface zone (biosphere) of mixing between the hydrothermal solution and the adjacent seawater.  相似文献   

Experimental method for quantifying resistance to the opening of netting panels   总被引：1，自引：0，他引：1  

Sala  A.; O'Neill  F. G.; Buglioni  G.; Lucchetti  A.; Palumbo  V.; Fryer  R. J. 《ICES Journal of Marine Science》2007,64(8):1573-1578

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Sample treatment with focused ultrasound and bath sonication as a powerful tool for the evaluation of cadmium pollution in estuarine waters     

R. Agapito  S. Alves  J.L. Capelo  M.L. Gonalves  A.M. Mota 《Marine Chemistry》2006,98(2-4):286-294

A new sample treatment was developed for the determination of dissolved cadmium in Tagus estuarine waters, based on focused ultrasound in conjunction with small volumes in the extraction steps for Cd pre-concentration. Cadmium was first pre-concentrated using a classical approach (APDC as the complexing agent and MIBK as the organic phase) and then back-extracted into HNO₃ with the aid of focused ultrasound, which reduced the acid concentration by more than one order of magnitude (from 4 to 0.1 mol L^− 3). This sample treatment was accomplished in less than 5 min, using low sample volume (20 mL), and low-volume, low-concentration reagents. The pre-concentration factor used in this work was 25, but different sample/organic volume ratios may be used in order to increase that value. The limit of detection and the limit of quantification in Tagus water samples were 0.03 nmol L^− 1 and 0.1 nmol L^− 3, respectively. Recoveries from spiked Tagus water were higher than 90%. The procedure was validated using the reference estuarine water NRC-SLEW-3. In the solubilization of Cd particulate, bath ultrasonication was used in conjunction with HNO₃ + HCl, followed by H₂O₂, which took about 2 instead of the usual 12 h (cooling included) when high-pressure microwave digestion is used.  相似文献   

Suspended sediment concentration in a buoyant plume: Fraser River,Canada     

R. A. Kostaschuk  B. A. Stephan  J. L. Luternauer 《Geo-Marine Letters》1993,13(3):165-171

A study of suspended sediment concentration in the buoyant plume of the Fraser River, Canada, showed that unstratified flow conditions at the river mouth caused resuspension of sandy bed material and high concentrations of coarse sediment. When flow at the mouth was stratified, sediment was fine-grained and concentrations were low. Application of a multivariate model revealed that suspended sediment concentration along the plume axis was controlled primarily by distance seaward of the river mouth, secondly by tidal height, and least by sediment concentration in the river.  相似文献   

A technique for conducting seismic refraction experiments on the ocean bed using bottom shots     

R. E. Kirk  K. Robertson  R. B. Whitmarsh  P. R. Miles 《Marine Geophysical Researches》1991,13(2):153-160

A technique has been devised for firing arrays of bottom shots on the ocean bed in depths upto 4000 m or more. Ten kilogram explosive charges are dropped from the surface while the shooting ship is navigated acoustically. They are detonated at preset times by an electronic timer which initiates an electrical detonator, detonating cord and cast PETN/TNT explosive. Ranges to ocean bottom seismographs, and the shot instants, can be calculated from the arrival-time differences of the direct and surface-reflected water waves. The accuracy, which is dependent on water-depth and range, was better than 22 m in range and 14 msec in shot instant for our experiments.  相似文献   

On the quality of North Sea cod stock forecasts     

Cook  R. M.; Kunzlik  P. A.; Fryer  R. J. 《ICES Journal of Marine Science》1991,48(1):1-13

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Wave group statistics from numerical simulations of a random sea     

S. Elgar  R.T. Guza  R.J. Seymour 《Applied Ocean Research》1985,7(2):93-96

Two commonly used methods of simulating random time series, given a target power spectrum, are discussed. Wave group statistics, such as the mean length of runs of high waves, produced by the different simulation schemes are compared. The target spectra used are obtained from ocean measurements, and cover a wide range of ocean conditions. For a sufficiently large number of spectral components, no significant differences are found in the wave group statistics produced by the two simulation techniques.  相似文献   

A nomogram method for predicting the movement of oil slicks     

V. R. Neralla 《Ocean Engineering》1987,14(2)

In order to obtain quick initial guidance on a first estimation of motion of the spilled oil, a simple manual procedure incorporating advection and spreading processes has been devised. This procedure involves the utilization of a nomogram based on simplified equations. Spill displacements throughout a given forecast period can be easily read from the nomogram. The technique is demonstrated with a real spill case.  相似文献   

Definition and analysis of multispecies otter-trawl fisheries off the northeast coast of the United States     

Murawski  S. A.; Lange  A. M.; Sissenwine  M. P.; Mayo  R. K. 《ICES Journal of Marine Science》1983,41(1):13-27

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