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911.
《气候与环境研究》编辑部 《气候与环境研究》2000,5(1):96-96
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{{if article.graphicalAbstractinfoCn && article.graphicalAbstractinfoCn != ""}}{{@ article.graphicalAbstractinfoCn}}{{/if}} 相似文献
912.
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{{if article.graphicalAbstractinfoCn && article.graphicalAbstractinfoCn != ""}}{{@ article.graphicalAbstractinfoCn}}{{/if}} 相似文献
913.
Large volumes of water often are produced with oil and gas from offshore platforms. The produced water is separated from the oil and gas and either reinjected into a deep formation or discharged to the ocean. The Norwegian oil and gas industry advocates ecological risk assessment as the basis for managing produced water discharges to the North Sea. In this paper, we compare estimates of ecological risks to water-column communities based on data on hydrocarbon residues in soft tissues of blue mussels deployed for a month near offshore platforms and based on predictions of the Dose related Risk and Effect Assessment Model (DREAM). The study was performed near produced water discharges to the Tampen and Ekofisk Regions of the Norwegian Sector of the North Sea. Because polycyclic aromatic hydrocarbons (PAH) are considered the most important contributors to the ecological hazard posed by produced water discharges, comparisons made here focus on this group of compounds. The mussel approach is based on predicted environmental concentrations (PECs) of individual PAH, estimated from PAH residues in mussels following deployment for a month near several produced water discharges, and predicted no effects concentrations (PNECs) based on a K(ow) regression model. In the DREAM method, PECs for three PAH fractions are estimated in the three-dimensional area around produced water discharge with the DREAM model. PNECs for each fraction are based on the chronic toxicity of a representative PAH from each fraction divided by an assessment factor to account for uncertainty in the chronic value. The mussel method gives much lower estimates of ecological risk than the DREAM method. The differences are caused by the much lower PNECs used in DREAM than derived from the regression model, and by the lower concentrations of aqueous PAH predicted by DREAM than estimated from PAH residues in mussel tissues. However, the two methods rank stations at different distances from produced water discharges in the same order and both identify 2- and 3-ring PAHs as the main contributors to the ecological risk of produced water discharges. Neither method identifies a significant ecological risk of PAH in the upper water column of the oil fields. The DREAM model may produce an overly conservative estimate of ecological risk of produced water discharges to the North Sea. 相似文献
914.
Abstract— We review the meteoritical and astronomical literature to answer the question: What is the evidence for the importance of ordinary chondritic material to the composition of the asteroid belt? From the meteoritical literature, we find that currently (1) our meteorite collections sample at least 135 different asteroids; (2) out of 25+ chondritic meteorite parent bodies, 3 are (by definition) ordinary chondritic; (3) out of 14 chondritic grouplets and unique chondrites, 11 are affiliated with a carbonaceous group/clan of chondrites; (4) out of 24 differentiated groups of meteorites, only the HE iron meteorites clearly formed from ordinary chondritic precursor material; (5) out of 12 differentiated grouplets and unique differentiated meteorites, 8 seem to have had carbonaceous chondritic precursors; (6) a high frequency of carbonaceous clasts in ordinary chondritic breccias suggests that ordinary chondrites have been embedded in a swarm of carbonaceous material. The rare occurrence (only one example) of ordinary chondritic clasts in carbonaceous chondritic breccias indicates that ordinary chondritic material has not been widespread in the asteroid belt; (7) cosmic spherules, micrometeorites, and stratospheric interplanetary dust particles—believed to represent a less biased sampling of asteroidal material—show that only a very small fraction (less than ~1%) of asteroidal dust has an ordinary chondritic composition. From the astronomical literature, we find that currently (8) spectroscopic surveys of the main asteroid belt are finding more and more nonordinary chondritic primitive material in the inner main belt; (9) the increase in spectroscopic data has increased the inferred mineralogical diversity of main belt asteroids; and (10) no ordinary chondritic asteroids have been directly observed in the main belt. These lines of evidence strongly suggest a scenario in which ordinary chondritic asteroids were never abundant in the main belt. The S-type asteroids may currently be primarily differentiated, but the precursor material is more likely to have been carbonaceous chondritic, not ordinary chondritic. Historically, carbonaceous material could have dominated the entire main belt. This could explain the presence in the inner main belt of asteroids linked to the primitive carbonaceous chondrites, and the absence of asteroids linked to the ordinary chondrites. The implications of this scenario for the asteroid heating mechanism(s) are briefly discussed. 相似文献
915.
《气候与环境研究》编辑部 《气候与环境研究》2000,5(3):328-328
{{@ convertAbstractHtml(article.abstractinfoCn, "cn")}}
{{if article.graphicalAbstractinfoCn && article.graphicalAbstractinfoCn != ""}}{{@ article.graphicalAbstractinfoCn}}{{/if}} 相似文献
916.
X-ray diffraction analyses of the mineral composition of sediments from the northwestern part of the Barents Sea show a higher content of kaolinite and mixed layered minerals than should be expected from this high-latitude position. The clay-mineral composition of the sediments in this part of the Barents Sea is controlled by glacial and subsequent marine reworking of underlying Mesozoic shales.Sediment supply from more distant sources of different compositions seems to be small both in Pleistocene and Recent sediments. 相似文献
917.
Triassic seismic sequence stratigraphy and paleogeography of the western Barents Sea area 总被引:2,自引:0,他引:2
Evy Glørstad-Clark Jan Inge Faleide Bjørn Anders Lundschien Johan Petter Nystuen 《Marine and Petroleum Geology》2010
A sequence stratigraphic framework of the Triassic on the Norwegian Barents shelf is presented. The Triassic succession was subdivided into five second-order sequences based on facies analysis of 2D seismic data constrained by well data. The sequences were separated by maximum flooding surfaces that correlate seismically for hundreds of kilometers. 相似文献
918.
919.
920.
The Salmon industry in Norway includes three sectors, namely sea and river fishing for wild salmon, and salmon farming, or aquaculture. The three sectors provide different social, economic and cultural benefits to society, but also face many problems and challenges. They have different interests, practices, traditions and audiences, and are also administered by different authorities and regulated under varying management regimes and legislations. On the one hand, they complement each other in terms of product supply, employment creation and income; on the other hand, they face conflicts over management objectives and strategies. This paper provides an overview of the salmon sectors associated with their status, challenges and management regimes. It further analyzes their interests and conflicts over economic contribution and management. Finally, some potential solutions are suggested in an attempt to solve these conflicts. 相似文献