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1.
渤海东侧海岸带黄土中的放射虫   总被引:1,自引:0,他引:1  
阐述了海岸带黄土中放射虫的种类及组合特征,并对其来源进行了探讨。 初步认为:放射虫最初是在间冰期高海面时被黄海暖流带入渤海的,后来在冰期低 海面时,裸露的海底受强大的西北向低空气流作用,致使一些放射虫壳体伴随沙尘 而沉降到附近海岸黄土之中。  相似文献   

2.
Since the beginning of the Continuous Plankton Recorder (CPR) survey in 1931, information on the abundance of a large number of plankton species or taxa has been obtained on a monthly basis in the northern North Atlantic. The many different ecological issues in which the survey has been involved have led to the application of a range of statistical methods. In this paper, we review some of the methods applied to the CPR data by presenting new and up-to-date analyses. Special attention is devoted to multivariate analysis, which has been used extensively to extract information from the CPR database. Results obtained from recently applied geostatistical methods on CPR data are then considered. An example of a time series decomposition by the use of Eigenvector filtering is presented to illustrate time-series analysis.  相似文献   

3.
The presence of probable salt dissolution-associated collapse structures in the North Sea based on the evidence of contemporary seismic data was discussed by Lohmann (1972). Since then, little attention has been paid to them in North Sea literature, although many oil companies will have studies on file. This Paper describes and illustrates a selection of such features in the area from recent seismic data, and suggest a broad classification for them as they are seen on the seismic section, based on mode of origin. Reference will also be made to certain types of carbonate dissolution and collapse effects.  相似文献   

4.
This paper explores how coastal data and information can be mobilised in information systems and applied in coastal management. The concept of an Information System is defined and described, and the potential role of Local Information System (LIS) in integrated coastal management (ICM) is considered. Three examples, from the Severn Estuary, UK the coast of the North West of England and North Wales, and the Fal and Helford estuaries, are used to demonstrate the requirements of a LIS for coastal areas. The role of GIS as part of the solution is considered in detail. The paper demonstrates how ideas from the disciplines of information systems and information science can be practically applied in coastal areas. The findings promote a holistic approach for those involved in the development of technologies and dealing with data and information about coasts and oceans.  相似文献   

5.
Differing seismic facies are observed from within the Westphalian sequences of the southern North Sea. A review of published synthetic seismograms and seismic data from known coal-bearing basins establishes seismic facies types and their relationships. Similar reflection character is recognized from Westphalian sequences in the southern North Sea and lithologies confirmed by borehole information. Probable sand/silt or clastic-prone Upper Coal Measures (Westphalian C/D) stages and coal-prone Lower and Middle Coal Measures (Westphalian A, B and part C) stages can be defined and mapped, providing information on the regional distribution of source and reservoir rocks and stratigraphic plays. It is suggested that sand-prone channel complexes or clastic dominated areas within the mainly A/B stages can be recognized and mapped, providing information on migration pathways and stratigraphic plays.  相似文献   

6.
Concern has been raised over whether environmental release of alkylphenols (AP) in produced water (PW) discharges from the offshore oil industry could impose a risk to the reproduction of fish stocks in the North Sea. An environmental risk assessment (ERA) was performed to determine if environmental exposure to PW APs in North Sea fish populations is likely to be high enough to give effects on reproduction endpoints. The DREAM (Dose related Risk and Effect Assessment Model) software was used in the study and the inputs to the ERA model included PW discharge data, fate information of PW plumes, fish distribution information, as well as uptake and elimination information of PW APs. Toxicodynamic data from effect studies with Atlantic cod (Gadus morhua) exposed to APs were used to establish a conservative environmental risk threshold value for AP concentration in seawater. By using the DREAM software to 1) identify the areas of highest potential risk and 2) integrate fish movement and uptake/elimination rates of APs for the chosen areas we found that the environmental exposure of fish to APs from PW is most likely too low to affect reproduction in wild populations of fish in the North Sea. The implications related to risk management of offshore PW and uncertainties in the risk assessment performed are discussed.  相似文献   

7.
长江口北支沉积物粒度特征及其环境意义   总被引:4,自引:0,他引:4  
通过对长江口北支兴隆沙XL2孔沉积物的粒度特征、环境磁学特征及微体古生物特征的分析,揭示长江口北支潮流沉积沙体的演变规律,进而推测长江口北支的演变规律,为长江口北支的开发整治提供科学依据。  相似文献   

8.
近30年长江口北支演变及其对物种多样性的影响   总被引:3,自引:1,他引:2  
分汊河口演变特征及其生态效应是当前河口海岸研究的重要热点问题。长江口北支是长江口第一级分汊的重要水道,其演变会对区域生态与环境条件产生深远的影响。本文在已有研究结果基础上,结合遥感影像分析与水域生态现状调研,阐述了近30年来长江口北支河道的演变特征和生态现状,并对河道演变对物种多样性的影响进行了深入的探讨。结果表明,近30年来北支演变的突出特点在于北支中上段束窄明显,而下段河道虽然有一定程度的束窄,但口门仍呈喇叭口形态;大量的圈围工程是导致北支中上段河道束窄的最重要因素;随着河势变化,北支分流比下降,分沙比上升,河道水深、河槽容积的下降,使北支盐水入侵加剧,水、沙、盐倒灌南支的风险增加。北支演变导致水体盐度条件的改变,使得区域生物类群以适应高盐、咸淡水环境的种类为主;而河道水深、水动力条件、水体含沙量等的变化均会对生物类群的组成产生影响。北支目前仍然是大型底栖动物、鱼类等生物类群的重要栖息地和育幼场,且具有较高的生物多样性。因此,北支治理仍需考虑维持北支水域生态系统的结构与功能不被破坏,确保区域的可持续发展。未来北支的演变趋势及其生态效应,需要在有效监测的基础上进行综合分析。  相似文献   

9.
Skolotnev  S. G.  Peyve  A. A.  Sanfilippo  A.  Ivanenko  A. N.  Ligi  M.  Veklich  I. A.  Petracchini  L.  Ponomarenko  E. P.  Basch  V.  Kuleshov  D. A.  Ferrando  C.  Dobrolyubov  V. N.  Sani  C.  Shkittin  N. A.  Bickert  M.  Dokashenko  S. A.  Muccini  F.  Yakovenko  E. S.  Palmiotto  C.  Pugacheva  T. L.  Cuffaro  M. 《Oceanology》2022,62(4):575-577
Oceanology - We provide information on geological and geophysical investigations of the structure of the area between the Bight and Charlie Gibbs transform faults in the North Atlantic during...  相似文献   

10.
A large amount of nutrient and chlorophyll data from the North Sea were compiled and organised in a research data base to produce annual cycles on a relatively fine spatial resolution of 1° in each horizontal direction. The data originate from many different sources and were partly provided by the ECOMOD data base of the Institut fur Meereskunde in Hamburg and partly by ICES in Copenhagen to cover the time range from 1950 to 1994. While the annual cycles of nutrients and chlorophyll derived for the continental coastal zone are representative for the decade 1984–1993 only, those for the remaining parts of the North Sea may be considered climatological annual cycles based on data from more than four decades. The composite data set of climatological annual cycles of medians and their climatological ranges is well suited to serve for validational and forcing purposes for ecosystem models of the North Sea, which have a resolution larger than or equal to 1° in both longitude and latitude. The annual cycles of the macronutrients and chlorophyll presented here for 1° × 1° squares in the North Sea show especially that sufficient observational data exist to provide initial, forcing and validational data for the simulations with the 130-box setup (ND130) of the ecosystem model ERSEM. The annual cycles presented give a clear picture for the whole of the North Sea. The highest concentrations occur at the continental coasts as a result of continued river input, which is added to the ongoing atmospheric input over the North Sea. Also, from the Atlantic Ocean water with relatively high nutrient concentrations enters the North Sea via the northern boundary. In the productive areas on and around the Dogger Bank nutrient concentrations are lower than in the other parts of the North Sea, even in winter. The areas with seasonal stratification have very different annual cycles in the upper (0–30 m) and lower layers (30 m-bottom). The shallow boxes are fully mixed and exhibit a relatively fast increase of nutrient concentrations caused by summer regeneration of nutrients.  相似文献   

11.
Shorebirds, as migratory aquatic birds and top predators in intertidal ecosystems, can be affected by global environmental changes and escalations in local impacts on coastal lagoons and estuarine trophic networks. Many shorebirds winter in North African Atlantic coastal sites, most likely because these locations provide constant and reliable food supplies with less energy costs in comparison with the wintering sites of northern Europe. Although more information is available for other important southern coastal sites (e.g. Saharan Atlantic coastal desert and Guinean mangroves coast), very little information is available for the North African Atlantic coast. Here, we focus on the impact of shorebird predation on benthic macroinvertebrates in a major wintering site in this area—Sidi Moussa coastal lagoon, Morocco—using an exclosure experiment. For most of the macroinvertebrate species there was no significant effect of the exclusion of shorebird predation. Overall, our results do not show evidence that predation by shorebirds influenced the overall standing biomass of the benthic community. This may indicate that the benthic productivity is high enough to provide constant and reliable food supplies for non-breeding shorebirds.  相似文献   

12.
《Marine Policy》1998,22(3):209-215
The North and West African coastal and marine areas discussed in this paper consist of the countries from Morocco to Libya for North Africa, and from Morocco to South Africa (up to the Cape of Good Hope) in West Africa. These marine areas consist of a wide to narrow continental shelf, estuaries, lagoons, coastal plains, isolated mountains, mangroves and wetlands. These areas are centres of productive socio-economic activities with a high population density, vast fisheries, and mineral resources. Presently, these resources are exploited with little attention for the environmental consequences. Sustainable management of the marine environment and its resources requires effective management plans and a human capacity to formulate, implement and monitor these plans. However, most of the countries still lack funds, human and infrastructural capacity for the management of their marine territories and its resources. Though there are many universities, research institutes and private organisations with a modest infrastructure for both data and information handling and the management of the marine environment, the region still lags behind in human and infrastructural capacity. Existing capacity development programmes by United Nations agencies, governments, universities, nongovernmental agencies, have so far not been very effective. A vigorous marine capacity building effort is needed to ensure the sustainable management of the marine environment in this African region. Externally funded programmes with a focus ensuring technology cooperation are needed. Such programmes must be based on mutual co-operation and participation of scientists and administrators from the region at all levels of programme formulation, implementation and assessment.  相似文献   

13.
The North Sea Regional Advisory Council (NSRAC) is the main forum through which fisheries interests are involved in Marine Spatial Planning (MSP) on the North Sea. The NSRAC is a relatively new and fragile forum involving various stakeholders. MSP confronts this group with a series of broader issues such as inter alia wind farms, transportation, and marine protected areas. The spatial focus involves both a reduction and a multiplication of the levels of geographical scale at which information for management must be resolved. The ongoing development of these institutions provides lessons about facilitating the evolution of cross-scale institutional linkages that strengthen adaptive, eco-system-based management.  相似文献   

14.
王焕  周晖  张明军 《海洋测绘》2020,40(4):55-58
冰标是中国北方海区冬季特有的航标,是为了保证我国北方冬季大量海上浮冰条件下航标的正常使用,由海事部门布设的冬季专用浮标。结合对我国北方海区冬季浮冰情况的分析,从冬季冰标的原理、构造、历年以来的布设情况和最新的技术发展等方面,阐述了冬季冰标是如何在浮冰环境中正常发挥工作,并通过对海图上合理表示冬季冰标的方法和原则进行探讨,提出区分不同的冰标类型,分别以正式通告和临时通告的形式在航海通告中发布冬季冰标的信息,以最大限度地保证冬季海上的航行安全。  相似文献   

15.
《Progress in Oceanography》2007,72(2-3):195-213
The broadcast spawner, Centropages typicus, is a very successful copepod species in many coastal areas of the Mediterranean Sea and North Atlantic Ocean. This review assembles the large amount of information on the reproduction and early life history of C. typicus that has emerged since the 1970s and has made this species one of the best-studied copepods, similar in that regard to species of Acartia and Calanus. Observations on mating behavior and the female gametogenic and oogenic cycles are presented, together with information on seasonal cycles of egg production rates in Mediterranean and Atlantic populations from various regions. These studies indicate a strong latitudinal gradient, with continuous reproduction and the main spawning season occurring earlier (late winter/spring) in warmer waters such as the Mediterranean Sea, compared to northern areas such as the North Sea and in the Kattegat, where C. typicus actively reproduces mainly in late summer and fall with reproduction ceasing altogether in winter in the German Bight. These observations strongly suggest that temperature is the controlling factor for reproductive activity in this species. Egg development times are also temperature dependent but do not vary with latitude, and there is as yet no conclusive evidence that diapause egg production occurs in C. typicus. Laboratory experiments have shown that food quantity and quality both affect fecundity and offspring fitness, but most of these studies have focused on diatom and dinoflagellate diets and non-algal prey have been strongly underrepresented, despite their importance for this omnivorous copepod. Large fluctuations in hatching success and naupliar survival have been reported in field surveys and have subsequently been related to maternal feeding history and food quality or toxicity in laboratory experiments. We identify future lines of research that will help to explain the interannual variability in breeding intensity and recruitment of C. typicus in the field based on better understanding of the species’ reproductive biology.  相似文献   

16.
The paper presents new information on the chemical composition of the insoluble aerosol fraction in the atmospheric surface boundary layer of different climatic zones of the North Atlantic (temperate humid, arid and semiarid, equatorial humid). The material for this study was collected during 12 expeditions. Nylon meshes were used to catch aerosols along the course of vessels. Aerosols above the North Atlantic consist of lithogenic, biogenic, and anthropogenic particles transported from different regions, which governs the differences in their concentrations and mineral and chemical compositions. Significant (by more than an order of magnitude) enrichment of aerosols in Cu, Cd, Zn, Pb, Sb, and Se is related to anthropogenic atmospheric pollution.  相似文献   

17.
我国沿海野生海藻中产量最大的首推马尾藻类,而北方沿岸所产马尾藻中以海蒿子(Sargassum pallidum)为最多,为我国北方建立褐藻胶工业的主要原料。 我国北方沿海产量较多的马尾藻中除海蒿子外,还有海黍子(S. kiellmanianum) 、鼠尾藻(S. thunbergii)等。为了扩大褐藻胶工业的原料范围,有必要对这些海藻中所含褐藻胶的质与量在全年生长期内的季节变化进行了解,以便考虑配合使用。 我国南方所产马尾藻的种类和数量都远较北方为多,据估计年产量至少比北方要多10倍,是我国南部水产资源中一项待开发的巨大财富。因此,对它们所含褐藻胶的质与量进行普遍的测定,对于这些天然资源的开发利用是不可缺少的资料。  相似文献   

18.
北黄海西部晚第四纪浅层地震剖面层序分析   总被引:3,自引:0,他引:3  
结合前人工作对北黄海西部7条浅层地震剖面测线进行解译,所揭示的晚第四纪U1-U4沉积单元的特征是:U1围绕山东半岛形成楔状沉积体,厚度从近岸地区的大于40m向海减薄到0m;U2平均厚度为15m,分布稳定,在研究区由东北向西南增厚;U3平均厚度为20m左右,西南薄,东北厚;U4只在部分剖面上有记录。测线显示,U2单元层中存在埋藏古河道,大部分被天然气充填,形成两条NE-SW向延伸的分支河道,初步认为其属于古黄河北支水系,位于全新世地层之下的晚更新世地层中,为黄河在晚更新世末期(15~9 kaBP)流经北黄海西部的产物。  相似文献   

19.
A contrasting study of the large-scale circulation features responsible for months or seasons with many hurricanes and those with few hurricanes has revealed that the frequency of hurricane formation over the North Atlantic Ocean is enhanced by the following conditions:There exists a well-developed subtropical high-pressure belt displaced to the north; a deep Icelandic low; a stronger-than-normal polar vortex with a deep polar trough dipping far southward along the eastern part of the United States; a dominant high-pressure ridge over western Canada and the United States; and a jet stream displaced northward over these regions. At 200 hPa, an anomalous anticyclonic circulation prevails over the subtropical North Atlantic. A stronger-than-normal upper easterly flow prevails. Positive sea surface temperature anomalies prevailing on a seasonal or long-term basis tend to be favorable for the formation of hurricanes.  相似文献   

20.
利用中央气象台台风实时业务定位资料和地面气象观测资料对2020年西北太平洋和南海的台风活动主要特征以及主要影响我国的台风路径、强度及风雨情况进行了统计分析.2020年西北太平洋和南海共有23个台风生成,较多年平均值(27.0个)偏少4.0个;有5个台风登陆我国,较多年平均值(7.0个)偏少2.0个.2020年台风活动的...  相似文献   

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