The importance of economics in explaining fisher behaviour andthe overexploitation of fisheries resources has been well established.Fishing in anything other than a subsistence-based economy isan economic activity. The species that fishers target, the levelof exploitation, and the gear that they use are all influencedby the benefits they receive (i.e. the revenue) and the coststhey incur. Fisheries management changes the set of incentives facing fishers,and in doing so changes their behaviour. In some cases, managementimposes additional costs on their operation directly (e.g. limitingoutput, or inefficient technology mixes arising from input controls),while in other cases, costs are imposed indirectly through anew set of incentives created (e.g. displacement of fishersfrom one area has an impact on other fishers already operatingin the areas to which they move). Changes in fisher behaviournot only influence the costs to the industry,  相似文献   

20.
海洋环境保护价值探析          下载免费PDF全文
谢素美  徐敏 《海洋开发与管理》2006,23(4):79-83
随着海洋开发的深度、广度的不断扩展,全球的海洋环境质量每况愈下,海洋环境保护问题日益成为国际社会普遍关注的热点。海洋环境保护价值观的模糊不清,导致了人们对海洋环境保护的忽视。鉴于此,文章对海洋环境保护的内在价值和外在价值及其相互关系进行初步探讨,以期引起对海洋环境保护的进一步重视。  相似文献   

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1.
High-resolution sonar surveys, and a detailed subsurface model constructed from 3D seismic and well data allowed investigation of the relationship between the subsurface geology and gas-phase (methane) seepage for the Coal Oil Point (COP) seep field, one of the world’s largest and best-studied marine oil and gas seep fields, located over a producing hydrocarbon reservoir near Santa Barbara, California. In general, the relationship between terrestrial gas seepage, migration pathways, and hydrocarbon reservoirs has been difficult to assess, in part because the detection and mapping of gas seepage is problematic. For marine seepage, sonar surveys are an effective tool for mapping seep gas bubbles, and thus spatial distributions. Seepage in the COP seep field occurs in an east–west-trending zone about 3–4 km offshore, and in another zone about 1–2 km from shore. The farthest offshore seeps are mostly located near the crest of a major fold, and also along the trend of major faults. Significantly, because faults observed to cut the fold do not account for all the observed seepage, seepage must occur through fracture and joint systems that are difficult to detect, including intersecting faults and fault damage zones. Inshore seeps are concentrated within the hanging wall of a major reverse fault. The subsurface model lacks the resolution to identify specific structural sources in that area. Although to first order the spatial distribution of seeps generally is related to the major structures, other factors must also control their distribution. The region is known to be critically stressed, which would enhance hydraulic conductivity of favorably oriented faults, joints, and bedding planes. We propose that this process explains much of the remaining spatial distribution.  相似文献   

2.
The relative concentrations of non-polar organic compounds in seawater and suspended particulate matter can be explained by an equilibrium sorption mechanism. The value of the quasi-equilibrium constant, K, was calculated with reasonable accuracy for polychlorinated biphenyls from a relatively simple equation which relies on both measurable physical parameters and a number of molecular terms estimated from fundamental physical chemical considerations. This model represents an approach to defining the accumulation of stable organic molecules on marine particulate interfaces within a coherent theoretical framework. As such, it provides a guide for selecting appropriate ecosystem parameters which influence the distribution and accumulation potential of these chemicals in the marine environment.  相似文献   

3.
This article summarizes the author's work on210Pb and210Po distributions in the marine environment for which the Okada Prize of the Oceanographical Society of Japan was awarded. In this review, the work of other investigators and the studies now going on are also included. The210Pb concentration in the surface water of the ocean is controlled by the atmospheric flux of210Pb and productivity. The disequilibrium between226Ra and210Pb in the deep sea reveals that the oceanic residence time of lead is less than a hundred years rather than of the order of thousands of years as thought before based on stable lead measurement in ocean water. Particulate removal of210Pb from the water column is likely to be the major cause of the deficiency of210Pb in the water, however more investigations would be needed to clarify the detailed removal mechanism of210Pb. The experiments on particulate flux by using sediment traps will provide an unique opportunity to examine this. 210Pb in excess of226Ra in sediment is useful for geochronology of shallow water sediments and the study on bioturbation rates on the deep sea sediments.  相似文献   

4.
The fate of marine seep gases (transport to the atmosphere or dissolution, and either bacterial oxidation or diffusion to the atmosphere) is intimately connected with bubble and bubble-plume processes, which are strongly size-dependent. Based on measurements with a video bubble measurement system in the Coal Oil Point seep field in the Santa Barbara Channel, California, which recorded the bubble-emission size distribution (Φ) for a range of seep vents, three distinct plume types were identified, termed minor, major, and mixed. Minor plumes generally emitted bubbles with a lower emission flux, Q, and had narrow, peaked Φ that were well described by a Gaussian function. Major plumes showed broad Φ spanning very small to very large bubbles, and were well described by a power law function. Mixed plumes showed characteristics of both major and minor plume classes, i.e., they were described by a combination of Gaussian and power law functions, albeit poorly. To understand the underlying formation mechanism, laboratory bubble plumes were created from fixed capillary tubes, and by percolating air through sediment beds of four different grain sizes for a range of Q. Capillary tubes produced a Φ that was Gaussian for low Q. The peak radius of the Gaussian function describing Φ increased with capillary diameter. At high Q, they produced a broad distribution, which was primarily described by a power law. Sediment-bed bubble plumes were mixed plumes for low Q, and major plumes for high Q. For low-Q sediment-bed Φ, the peak radius decreased with increasing grain size. For high Q, sediment-bed Φ exhibited a decreased sensitivity to grain size, and Φ tended toward a power law, similar to that for major seep plumes.  相似文献   

5.
Biotransformation of polycyclic aromatic hydrocarbons in marine polychaetes   总被引:2,自引:0,他引:2  
Deposit-feeding polychaetes constitute the dominant macrofauna in marine environments that tend to be depositional centers for organic matter and contaminants. Polychaetes are known to accumulate polycyclic aromatic hydrocarbons (PAHs) from both particulate and dissolved phases but less is known about the mechanisms underlying elimination of accumulated PAHs. An important pathway of elimination is through biotransformation which results in increased aqueous solubility of the otherwise hydrophobic PAHs. Biotransformation in marine polychaetes proceeds in a two phased process similar to those well studied in vertebrates, phase I enzymes belonging to the Cytochrome P450 (CYP) enzyme family, along with a few phase II enzymes have been identified in marine polychaetes. In this review we aim at highlighting advances in the mechanistic understanding of PAH biotransformation in marine polychaetes by including data obtained using analytical chemistry and molecular techniques. In marine polychaetes induction of CYP enzyme activity after exposure to PAHs and the mechanism behind this is currently not well established. Conflicting results regarding the inducibility of CYP enzymes from polychaetes have led to the suggestion that induction in polychaetes is mediated through a different mechanistic pathway, which is corroborated by the apparent lack of an AhR homologous in marine polychaetes. Also, none of the currently identified CYP genes from marine polychaetes are isoforms of those regulated by the AhR in vertebrates. Relatively few studies of phase II enzymes in marine polychaetes are currently available and most of these studies have not measured the activity of specific phase II enzymes and identified phase II metabolites but used an extraction technique only allowing determination of the overall amount of phase II metabolites. Studies in insects and various marine invertebrates suggest that in invertebrates, enzymes in the important phase II enzyme family, UDP-glucuronosyl transferases primarily use glucoside as co-substrate as opposed to the vertebrate cosubstrate glucuronic acid. Recent studies in marine polychaetes have however identified glucuronidation of PAHs indicating no mechanistic difference in co-substrate preference among UDP-glucuronosyl transferases between vertebrates and marine polychaetes but it might suggest a mechanistic difference between marine polychaetes and insects.  相似文献   

6.
7.
The research described in this paper involves a method to mitigate the vibration of an offshore structural system in the marine environment when subjected to the in-plane wave forces. The method introduced include a practical application for the viscoelastic material to the offshore structural system, and the analytical technique to evaluate the structural responses when the system is incorporated with damping devices. The viscoelastic materials applied here were tested and verified that they have high energy absorption capacity. In the analysis, the applied wave forces are based on the fifth-order Stokes wave theory and Morrison equation for small body and the computation method is based on Newmark method for nonlinear system. Results of the vibration responses for the system with added damping devices are presented and compared to the responses of structures of the traditional design. It was observed that the effect of the vibration mitigation was significant and the dynamic performance of the offshore structural system were greatly improved when the new damping devices were applied.  相似文献   

8.
Detailed measurements of bubble composition, dissolved gas concentrations, and plume dynamics were conducted during a 9-month period at a very intense, shallow (22-m water depth) marine hydrocarbon seep in the Santa Barbara Channel, California. Methane, carbon dioxide, and heavier hydrocarbons were lost from rising seep bubbles, while nitrogen and oxygen were gained. Within the rising seawater bubble plume, dissolved methane concentrations were more than 4 orders of magnitude greater than atmospheric equilibrium concentrations. Strong upwelling flows were observed and bubble-rise times were ~40 s, demonstrating the rapid exchange of gases within the bubble plume.  相似文献   

9.
Immune inhibition in marine mussels by polycyclic aromatic hydrocarbons   总被引:2,自引:0,他引:2  
Polycyclic aromatic pollutants produced by a range of industrial processes and the combustion of fossil fuels. They eventually enter the marine environment, and are bioaccumulated in the tissues of sessile, filter-feeding bivalves, causing a variety of sublethal effects. Few studies, however, have examined immune inhibition in molluscs by these xenobiotics. Here, the immunotoxic effects of PAHs were investigated in marine mussels (Mytilus edulis) by means of in vivo exposure experiments. Animals were exposed to a PAH cocktail of anthracene, fluoranthene and phenanthrene for 2 or 4 weeks. The haemolymph was then extracted, and phagocytosis and lysosomal neutral red retention assays performed to examine the effects of PAHs on particle uptake by haemocytes and lysosome integrity, respectively. PAHs were found to inhibit phagocytosis and damage lysosomes. It is hypothesized that PAHs exert their toxicity directly on the lysosomes. A possible consequence of such lysosomal damage will be immune impairment in mussels leading to reduced resistance to infectious diseases.  相似文献   

10.
刘健  姜晓轶  范湘涛 《海洋通报》2014,33(2):235-240
从数据模型和数据可视化这两方面对近10年来的海洋环境数据可视化研究进展进行了总结。海洋环境信息的可视化研究呈现出"从2维到n维,从数据可视化到面向知识发现的可视化"的发展趋势。目前,国内对海洋要素可视化表达的研究主要集中在"空间三维+时间维"的四维时空过程可视化表达,对海洋环境多维数据表达的研究还处于探索发展阶段。基于海洋环境多维时空数据模型,结合信息可视化中的多维数据可视化挖掘方法,建立面向知识发现的海洋环境数据多维可视化环境,挖掘多维要素之间的相互关系是今后研究的方向。  相似文献   

11.
Seabirds as monitors of the marine environment   总被引:15,自引:1,他引:15  
  相似文献   

12.
The solubility of natural 7Be from air particulate matter in seawater was determined as a function of time. Adsorption of the thus solubilized 7Be on a variety of substrates was investigated. 7Be appears to be strongly adsorbed on suspended matter and inorganic materials at high suspended loads (> 20 mg 1−1), but at natural levels (1 mg 1−1) is only partially adsorbed. Further, at natural concentrations of suspended matter, adsorption of 7Be appears to be directly proportional to suspended load. Because a non-steady-state flux of 7Be to the bottom could be expected over its 53-day half-life, 7Be may be a poor tracer of sedimentation rates and sediment redistribution processes.  相似文献   

13.
在对我国海洋环境管制必要性进行论证的基础上,文章重点分析了海洋环境管制的现状和问题,并结合我国海洋环境管制的现实,提出了加强和变革海洋环境管制的几点思考意见。  相似文献   

14.
金秋九月,秋风送爽,首届全国海洋科技大会在北京胜利召开。此次大会的召开恰逢我国全面贯彻国家中长期科学技术规划的第一年,是我国建国以来首次以“海洋科技”为主题的海洋会议,会议以《国家中长期科学技术规划(2006-2010)》为指导,研究讨论了《国家“十一五”海洋科学和技术发展规划纲要》与《关于加快海洋科学技术发展若干意见》,部署了我国海洋科技发展的重点,明确了我国今后海洋科技工作的目标和方向,为共同构建海洋科技创新体制打下了良好的基础。  相似文献   

15.
海洋环境观测技术研究进展   总被引:17,自引:0,他引:17  
回顾了近年来海洋观测技术发展的基本情况和主要成果,同时指出了海洋观测技术的局限性,与数值模拟技术相结合的必要性,以及加强发展海啸、风暴潮和孤立内波等灾害性强海洋动力过程的监测技术和预警研究的迫切性。  相似文献   

16.
基于单片机的海洋环境监测系统的控制电路设计   总被引:1,自引:0,他引:1  
设计并实现了一种基于C8051F340单片机的节能型自治式多功能海洋环境监测系统的控制电路.该电路利用模块化设计方法,通过合理选用器件和设计器件的工作模式,使控制电路具有低功耗、高可靠的特点.实验表明,该控制电路实现了潜标式主浮体对浮标式搭载平台的实时控制,同时实现了浮标搭载平台单向下潜、定点测量、自由上浮、自动避碰等状态的控制,方法简单新颖,实现了对海洋要素的长期连续观测.  相似文献   

17.
This investigation was undertaken to assess the chemical nature, occurrence, and possible origin of petroleum hydrocarbons in the Great Barrier Reef ecosystem. Aliphatic hydrocarbons in surface sediments, water, and a suite of seven species from widely separated coral reefs in the Great Barrier Reef area were analysed by gas chromatography, and by gas chromatography coupled with mass spectrometry. The hydrocarbons found were substantially of biogenic origin. The major components were n-pentadecane, n-heptadecane, pristane and mono-alkenes based on heptadecane, and were believed to originate from benthic algae and phytoplankton. There was no evidence to suggest that lipid content had any influence on hydrocarbon content. Hydrocarbons from the organisms and sediments have characteristic composition patterns which would be altered by the presence of petroleum hydrocarbons. An unresolved complex mixture, usually considered indicative of petroleum contamination, was found in greater than trace amounts only in Holothuria (sea cucumber) and Acropora (coral) from the Capricorn Group, and in some sediment samples from the Capricorn Group and Lizard Island area.  相似文献   

18.
A White Paper on a new integrated management plan for the Norwegian Sea was launched by the Norwegian government in May 2009. Following international guidelines for ecosystem-based management, the plan provides an overall framework for managing all human activities (mainly oil and gas industry, fishing, and shipping) in the area to ensure the continued production and function of the ecosystem. The plan is based on an assessment of the present and projected future impact of human activities and of the interactions between them, taking into account deficits in current knowledge of ecosystem state and dynamics. Areas of particular value in terms of biodiversity or biological production were identified. In each of these valuable areas, any access for substantial human activity is to be carefully managed. To monitor the overall development of the Norwegian Sea, a set of indicators with associated environmental quality objectives have been selected. The approach used builds upon experience gained from the first integrated Norwegian management plan for a marine area, the Barents Sea–Lofoten region, developed in 2002–2006. Work towards a Norwegian management plan for the North Sea, including Skagerrak, was initiated in 2009.  相似文献   

19.
Economics, fisheries, and the marine environment   总被引:1,自引:2,他引:1  
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