排序方式: 共有55条查询结果,搜索用时 11 毫秒
41.
Thomas Richerol Andr Rochon Steve Blasco Dave B. Scott Trecia M. Schell Robbie J. Bennett 《Journal of Marine Systems》2008,74(3-4):825
In order to document long-term climate cycles and predict future climate trends for the Arctic, we need to look at the geological records to establish the link between historical and pre-historical sea-surface parameters. Dinoflagellate cysts (dinocysts) are used as proxy indicators of sea-surface parameters (temperature, salinity, sea-ice cover, primary productivity) jointly with transfer functions and a modern dinocyst reference database, to reconstruct the evolution of sea-surface conditions at decadal and millennial timescales. Here we present the surface distribution of recent dinocyst assemblages from 34 surface sediment samples collected on the Mackenzie Slope/Amundsen Gulf during the 2004 CASES (Canadian Arctic Shelf Exchange Study) cruise. Dinocyst concentrations in surface sediments are relatively high outside the Mackenzie plume area and increase gradually eastward toward Amundsen Gulf. The cysts of autotrophic dinoflagellates are dominant throughout the study area, while the maximum abundance of heterotrophic taxa is found within the Mackenzie plume. Hierarchical clustering analyses allowed defining two dinocyst assemblages. Assemblage I is located on the Mackenzie Slope and southern Amundsen Gulf, while Assemblage II is located within the Cape Bathurst Polynya area in northern Amundsen Gulf. Both assemblages are dominated by Operculodinium centrocarpum, but are distinguished on the basis of the relative abundance of Islandinium minutum, a taxon generally associated with sea ice. I. minutum is found in lower abundance in the Cape Bathurst Polynya. 相似文献
42.
文中系统分析了北部湾港口资源的情况,并分析了北部湾港口资源发展存在核心竞争力不强、“铁路瓶颈”制约、港口自身造血功能差等问题阻碍了港口资源的发展,港口资源需要进行整合。在探讨完港口资源整合具备可行性的基础上,进行了港口资源整合目的、定位、范围和模式等方面的思考,并在此基础上提出北部湾港口资源应该突破瓶颈,做到“六个统一”,走体制创新之路。 相似文献
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介绍目前阿拉伯半岛地区如火如荼的城市轨道交通建设,回顾并且分析迪拜、科威特、阿曼、卡塔尔、沙特阿拉伯等一些海湾地区城市和国家轨道交通系统的规划、建设和运营情况。 相似文献
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文章基于北部湾海域油类污染防治的紧迫性和艰巨性,探讨了北部湾海域油类污染的成因,分析了现阶段北部湾海洋油类污染防治存在的问题,并提出了防治北部湾海洋油类污染的措施。 相似文献
45.
One hundred and ten fixed, tensioned, and moored structures have been installed in the Gulf of Mexico in water depth greater than 400 ft, and through 2012, 15 structures have been decommissioned. Decommissioning is the final stage of an assets life cycle, where all wells are plugged and abandoned, the structure and associated production facilities are removed, and the seafloor cleared of all debris created by the operations. The purpose of this paper is to describe a decommissioning forecast for deepwater structures in the Gulf of Mexico. Three approaches (“simple models”) based on lease status, gross revenue, and production forecasting are applied to infer a short, medium, and long-term decommissioning forecast. Model assumptions are outlined along with a discussion of the limitations and uncertainty of analysis. About two dozen deepwater fixed platforms are expected to be removed over the next decade, but only 5 floaters are expected to be decommissioned through 2032. 相似文献
46.
该文详细介绍了青岛海湾大桥接线工程的工程概况、技术标准、总体设计及立交与匝道的设置,工程设计中体现了在满足交通功能的前提下,近远期结合,充分利用现状和考虑城市景观环境的需要,因地制宜确定立交方案,降低工程投资的设计思想。 相似文献
47.
Lidia Dzierzbicka-G
owacka 《Journal of Marine Systems》2005,53(1-4):19-36
A nutrient–phytoplankton–zooplankton–detritus (1D-NPZD) ‘phytoplankton {Phyt} and Pseudocalanus elongatus {Zoop} dynamics in the spring bloom time in the Gda
sk Gulf. The 1D-NPZD model consists of three coupled, partial second-order differential equations of the diffusion type for phytoplankton {Phyt}, zooplankton {Zoop}, nutrients {Nutr} and one ordinary first-order differential equation for benthic detritus pool {Detr}, together with initial and boundary conditions. In this model, the {Zoop} is presented by only one species of copepod (P. elongatus) and {Zoop} is composed of six cohorts of copepods with weights (Wi) and numbers (Zi); where
. The calculations were made for 90 days (March, April, May) for two stations at Gda
sk Gulf with a vertical space step of 0.5m and a time step of 900 s. The flow field and water temperature used as the inputs in the biological model 1D-NPZD were reproduced by the prognostic numerical simulation technique using hydrographic climatological data. The results of the numerical investigations described here were compared with the mean observed values of surface chlorophyll-a and depth integrated P. elongatus biomass for 10 years, 1980–1990. The slight differences between the calculated and mean observed values of surface chlorophyll-a and zooplankton biomass are ca. 10–60 mg C m−3 and ca. 5–23 mg C m−2, respectively, depending on the location of the hydrographic station. The 1D-NPZD model with a high-resolution zooplankton module for P. elongatus can be used to describe the temporal patterns for phytoplankton biomass and P. elongatus in the centre of the Gda
sk Gulf. 相似文献
48.
This paper presents new data on distribution patterns of modern benthic foraminifera and other microfossils from the Canadian Arctic, specifically the Beaufort Shelf and slope. The material was collected in June to August of 2004 and is the first of its kind in this area to be collected since 1970. We examined the smaller sizes (45–63µm) as well as > 63µm and discovered that many species had been severely underrepresented in previous studies. Deep sea forms, that had been overlooked previously, were common on the shelf; two species (Elphidiella arctica and Ammotium cassis) appeared in preliminary results to be indicators of methane seepage; and it was possible to make determinations of sea-ice coverage using a combination of foraminifera and tintinnids (planktic ciliates). Our data indicated the presence of many of the same species as previous studies from this area, but improved techniques of sample processing greatly increased the number of specimens and species found (particularly the small deep sea arctic species Buliminella hensoni and Bolivina arctica) which provide much more reliable data for paleoceanographic determinations. One of the primary objectives for this work was to provide baseline data to help determine paleo-ice cover; these data cover a broad range of conditions on the Beaufort Shelf that make it possible to achieve this objective as well as improving what it is known about the assemblages on this shelf as compared to other arctic shelf areas, such as the Siberian Shelf). 相似文献
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文章针对广西北部湾港口保税物流业务培训现状,介绍了德国、新加坡职业培训模式及其共性和特点,分析了广西北部湾港口保税物流业务培训中存在的问题,并提出完善广西北部湾港口保税物流业务培训的相关措施。 相似文献