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991.
A. Banerjee M. Jha A. K. Mittal N. J. Thomas K. N. Misra 《Marine and Petroleum Geology》2000,17(10):7
Source rock screening reveals five laterally extending potential sources (PS) in the Paleogene. The PSs are SR5 and SR6 in dominantly marine early Eocene to late Paleocene Cambay Shale formation, and SR7, SR8/9, and SR11/12 in dominantly freshwater early Paleocene Olpad formation. Only 3 PSs, SR11/12, SR8/9, and SR7 have attained vitrinite reflectance of 0.75% at 45, 7, and 2 mybp, respectively. Chromatographic and isotope data of oils and PS samples suggest that mainly the Olpad source rocks: SR7 and SR8/9 contributed to the discovered oils. The Cambay Shale source rocks, SR5 and SR6, contrary to the prevalent view, possibly have no significant contribution towards the accumulated oils. 相似文献
992.
We report on a marine electromagnetic (EM) survey across two portions of the New Jersey continental margin that have been previously shown to contain buried paleo-channels. The EM method used provides bulk porosity estimates to depths of around 20 m below the seafloor and is thus able to place porosity constraints on the nature of the channel infill and the contrast in physical properties across the channel boundaries. Our data show that a key condition for the channels to have an electrical signature is that they incise an underlying regional unconformity, R, thought to represent a subaerially eroded surface, exposed during the late Wisconsinan glaciation. Channels that cut R are seen through increases in apparent porosity. Another seismically imaged channel sequence, which lies within the outer-shelf sediment wedge sequence above R, does not have an electrical signature, indicating that the sediments above and below the channel boundaries have similar physical properties. 相似文献
993.
On the basis of the generalized data of multiannual observations (1985–1994), we analyze the seasonal variability of the vertical
and spatial distributions and composition (Csos, Nsos, Csos/cha, and C/N) of suspended organic substances (SOS) in the shelf zone and in the upper active layer of the abyssal part of the
Black Sea. The results of our analysis enable us to conclude that only a narrow coastal band of the shelf in the northwest
and west parts of the sea suffers to an extremely pronounced anthropogenic impact, which manifests itself in a significant
increase in the mass of suspended organic substances. The formation of new organic substances and, hence, the mass of suspended
organic substances in these regions attain the level of eutrophic waters in the late-spring and summer periods. In the open-sea
region, the anthropogenic impact is less pronounced and the spatial distribution of suspended organic substances is determined
by the general dynamics of waters and the intensity of phytoplankton production.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
994.
We study the influence of baroclinic tidal waves on the diffusion of an impurity spot in a continuously stratified fluid.
The equation of turbulent diffusion is solved numerically by taking into account the wave currents. We establish the dependences
of the characteristics of the diffusion process on parameters of baroclinic waves and the location of the impurity spot.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
995.
We analyze the seasonal variability of the climatic hydrophysical fields of the Black Sea reporduced in three numerical experiments
carried out according to the model of circulation. The numerical predictions are performed for a period of 12.5 yr on the
basis of the hydrological data accumulated in 1983–1995. The monthly average climatic fields of the current speed are reconstructed
according to the data on the climatic fields of temperature and salinity by the method of hydrodynamic adaptation (standard).
It is shown that, in prognostic calculations, the seasonal variability of temperature and salinity is qualitatively close
to the “standard” dependence. At the same time, the quantitative difference between the climatic behavior of the model and
the standard dependence may be significant. The annual cycle of the currents is characterized by the intensification of the
Main Black-Sea Current in winter. The structure of the hydrophysical fields of the sea in the model becomes much more realistic
if it is based on the actual hydrological data.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
996.
Concentration-dependent effects of nonylphenol on testis structure in adult platyfish Xiphophorus maculatus. 总被引:1,自引:0,他引:1
Nonylphenol has been found to exert estrogenic effects in fish and may affect the fertility of male fish. The objective of this study was to use the platyfish, Xiphophorus maculatus, as a model to evaluate the concentration-dependent effects of nonylphenol on the testicular structure. A tendency of a concentration-dependent decrease in the gonadosomatic index was observed after 28 days of treatment with nonylphenol. Histological examination revealed marked effects of nonylphenol on the testis structure. The effects were more pronounced at the higher concentrations of nonylphenol. This study strongly suggests that exposure to nonylphenol can result in decreased fertility in X. maculatus males. 相似文献
997.
A micro-extraction technique was used to examine in vivo polycyclic aromatic hydrocarbon (PAH) metabolism in 10 small invertebrate species exposed to sediments amended with 3H-benzo[alpha]pyrene (BaP). Phyla examined included Mollusca (Hydrobia totteni, Ilyanassa obsoleta, Yoldia limatula, and Gemma gemma), Annelida (Nereis succinea, Pectinaria gouldii, Haploscolopolous sp., and Capitella sp. 1) and Arthropoda (Edotea triloba, and Gammarus mucronatus). Organisms were exposed to BaP-labeled sediments, harvested, and parent BaP separated from all polar metabolites by liquid extraction The percent of BaP-derived radio-activity present as polar metabolites ranged from 96% for N. succinea to 7% for P. gouldii. Wide ranges in metabolic capability were also observed between species in the other two phyla examined. Reverse-phase HPLC analysis of extracts of representative species from each phyla indicated that all these organisms form bay region metabolites, with two species forming the 7,8-dihydrodiol (N. succinea and G. mucronatus). In light of the high variability in metabolic capability observed within each phylum, species-specific information on metabolic ability should be obtained before assessing bioaccumulation, critical body burdens, or trophic transfer of PAHs in invertebrates. 相似文献
998.
J P Shaw A T Large J K Chipman D R Livingstone L D Peters 《Marine environmental research》2000,50(1-5):405-409
Mytilus edulis digestive gland microsomes were prepared from indigenous populations sampled from a clean reference site (Port Quin) and an urban-industrial contaminated site (Blackpool) in the UK. Samples were collected in March/April, May, August and December 1998. Western blot analysis was performed using polyclonal antibodies to fish CYP1A and rat CYP2E using partially purified M. edulis CYP as a positive control, to aid identification. CYP1A- and CYP2E-immunopositive protein levels showed different site-specific seasonal variation with higher levels of CYP2E determined in May (P < 0.05). At both sites, lower levels of CYP1A-immunopositive protein but not CYP2E-immunopositive protein were observed in the samples collected in December (P < 0.05). This correlated with lower levels of nuclear DNA damage (Comet assay expressed as per cent tail DNA) observed in December compared to August (P < 0.05). 相似文献
999.
1000.
G. Chronis V. Lykousis D. Georgopoulos V. Zervakis S. Stavrakakis S. Poulos 《Progress in Oceanography》2000,46(2-4)
Seawater along the southern margin of the Cretan Sea (May 1994–September 1995) has been found to have light transmission values ranging from 79% to 94%, corresponding to SPM values ranging from 1.5 mg l−1 to 0.2 mg l−1. The highest SPM concentrations (mostly of terrigenous origin) were found close to the sea-bed over the shelf-break and upper slope. The origins of SPM in the surface waters (<150 m) is principally biogenic. The occurrence of nepheloid layers at intermediate depths within the upper water column is mostly a result of density stratification. The dynamics of SPM distributions are governed by the 2-gyre system which induces a general onslope flow; and so inhibits the seaward dispersion of the relatively more turbid coastal/shelf waters. This is in agreement with the virtual absence of suspensates of terrigenous origin offshore of the shelf-break. Near bottom nepheloid layers (BNL) and detached intermediate nepheloid layers occur in the vicinity of the shelf-break and over upper slope region; these may be explained by resuspension induced by near-bed current activity and breaking of internal waves. High concentrations of SPM near the seabed may be caused by anthropogenic (trawling) activity. Occasionally, the formation of BNL may result from local seismic activity resulting in gravity-driven mass movements. 相似文献