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1.
Jon Day   《Marine Policy》2008,32(5):823-831
An increasing number of scientists and resource managers recognise that successful marine management approaches, including marine spatial planning (MSP), cannot occur without effective monitoring, evaluation and adaptation. These basic components are necessary to ensure that any marine planning or marine management measures are both effective and efficient. While a number of fundamental principles for marine monitoring, evaluation and adaptive management exist, there are varying levels of understanding about how these should be undertaken and what they may achieve. Challenges include the development of realistic and measurable objectives and indicators against which effectiveness can be practically measured. The matter becomes even more complicated as the focus of marine planning and management strategies changes from ‘single species’ to ‘habitats’ and ‘ecosystems’ that may enable a diversity of permitted uses consistent with a variety of overall objectives. Over the last 30 years, the Great Barrier Reef Marine Park (GBRMP) has successfully established a multiple-use spatial management approach that allows both high levels of environmental protection and a wide range of human activities. Drawing on this unique long-term experience in the GBRMP, this article discusses key aspects of effective monitoring and evaluation, and summarises lessons learned from over two decades of adaptive management.  相似文献   

2.
An alternative coordinate system for solving finite difference ocean models   总被引:1,自引:2,他引:1  
M. Herzfeld   《Ocean Modelling》2006,14(3-4):174-196
An alternative ‘compressed’ coordinate system for representing finite difference grids in ocean models is presented and compared with the traditional Cartesian method. The alternative method represents any arbitrary three-dimensional domain as a one-dimensional vector. Advantages of using this method include the exclusion of all land ‘dry’ points from the computational grid, leading to savings in the memory used and increased execution speed where domains have a low ratio of wet to total computational cells. The Cartesian and compressed models are applied to a variety of domains to assess the performance of each in terms of memory use and computational speed.  相似文献   

3.
Marine pollution from plastic debris is a global problem causing negative impacts in the marine environment. Plastic marine debris as a contaminant is increasing, especially in Canada. While the impacts of macroplastics are well known in the literature, there are relatively few policy studies related to mitigating microplastic toxicity in the environment. Despite overwhelming evidence of the threat of plastic in the marine environment, there remains inadequate or limited policies to address their mitigation, particularly microplastic debris. Existing policies for waste management, marine debris monitoring and awareness campaigns were evaluated from other jurisdictions. Policies and recommendations were developed for the Canadian context. Recommendations include improved practices for: (1) law and waste management strategies; (2) education, outreach and awareness; (3) source identification; and (4) increased monitoring and further research.  相似文献   

4.
As in much of Oceania, Palauan society of the pre-European contact era practiced sophisticated systems of tenure and management that extended to the fish and other resources of the surrounding coral reefs and lagoons. With its colonial experiences, the opening up of economic and social links with the outside world, and the introduction of highly efficient fishing technologies, Palau’s customary marine resource management systems have eroded.Like most Pacific Island countries, the Republic of Palau only recently gained independence from a western administrating nation. Its constitution, being based on western models, emphasizes democratic and egalitarian ideals. At the same time, it seeks to preserve and revitalize many aspects of customary Palauan society, particularly its institutions and processes of chiefly authority. These customs, however, are based on titled elitism and other principles contrary to those emphasized in the constitution. Through a combination of a series of court decisions that illustrate the incompatibility of the two bodies of law and a lack of any legislative initiative that could reconcile them, the exercise of purely customary authority has been relegated to matters of only minor importance. Thus, as in many Pacific Island nations, independence has contributed to the erosion of traditional tenure and management systems.Some recent village-level initiatives, however, may portend an important shift back toward decentralized, if not exactly traditional, control over the use of Palau’s inshore resources. The constitution’s critical provision that inshore resources are owned by the 16 states has allowed these relatively new village-level political and social units, with their mix of titled and elected leaders, to exert increasing control over inshore resources. They have done so in response to increasing resource scarcity owing to increasing fishing pressure, increasing demand by the booming marine-based tourism sector, and impending resource degradation from physical development. The effectiveness of these emerging local-level management regimes will be determined largely by the degree of support offered by the national government. Little has been forthcoming. The executive branch has been hesitant to support the marine property rights of the states, the judiciary has interpreted the constitution in a manner that has limited the authority of traditional leaders, and the legislature has not enacted laws that might guide the other two branches in interpreting and implementing the constitution with regard to either customary law or state ownership of marine resources.  相似文献   

5.
C. Arnosti   《Marine Chemistry》2004,92(1-4):263
The observation that a fraction of organic matter produced in marine systems evades the concerted efforts of microbial communities and is buried in sediments suggests that there are ‘speed bumps’ in carbon degradation pathways that impede microbially driven remineralization processes. The initial step in degradation of macromolecules, extracellular enzymatic hydrolysis, is often stated to be ‘the’ rate-limiting step in carbon remineralization. Experimental investigations described here, however, demonstrate that at least in certain cases, microbes produce extracellular enzymes on time scales of hours to tens of hours in response to substrate addition, and hydrolysis is extremely rapid. If enzymatic hydrolysis can be rapid, what factors slow or stop organic matter degradation? A lack of the correct inducer to initiate enzyme production, and/or a lack of the correct organism to produce the required enzyme, may result in a complete lack of hydrolysis in certain environments—a barricade, rather than a speed bump. Preliminary evidence supporting this hypothesis includes a comparison of polysaccharide hydrolysis in seawater and sediments, which demonstrates that the spectrum of enzymes active in seawater and sediments are fundamentally different. Furthermore, a survey of enzyme activities in surface waters from a range of locations suggests that pelagic microbial communities also differ widely in their abilities to express specific extracellular enzymes. Trans-membrane transport through porins is yet another potential location of structure-related selectivity.Our efforts to identify speed bumps and barricades are hampered by our inability to structurally characterize in sufficient detail the macromolecular structures present in marine systems. Furthermore, assessments of organic matter ‘quality’ from a chemical perspective do not necessarily accurately reflect the availability of organic carbon to microbial communities. For these communities, in fact, ‘quality’ may be a variable, which depends on the enzymatic and uptake capabilities of community members. To begin to assess substrate structure and quality from a microbial perspective, we will have to combine specific knowledge of macromolecular structures with detailed investigations of the enzymatic and transport capabilities of heterotrophic marine microbes.  相似文献   

6.
During the past decade, knowledge about the ecology and the environment of giant carbonate mounds has been growing continuously. However, still little is known about their growth dynamics. Three gravity cores from Galway Mound, Belgica Mound Province in the Porcupine Seabight off Ireland, were investigated for their sedimentological, geophysical and geochemical properties to get insight into the long-term development of this cold-water coral covered carbonate mound. These data were supplemented by radiometric age determinations on planktonic foraminifera and coral skeletons. The records from three different settings on Galway Mound reveal a coherent growth history that in general is similar to what is known from other carbonate mounds at the Irish margin. However, whereas other cores are often disturbed by numerous and not correlateable hiatuses, Galway Mound, in contrast, appears to be characterised by only one major hiatus representing a time gap of ~ 250 kyr. Several mechanisms are discussed in this study as possible causes for the observed stratigraphic record at Galway Mound. The most likely explanation is that the hiatus has its origin in a major mass wasting event on an instable, possibly glacial, unit that could have acted as a slip plane. The overall Late Quaternary growth history of Galway Mound fits well into existing cyclical mound development models, pointing to Galway Mound being an ‘actively growing’ mound (“coral bank stage”) at present.  相似文献   

7.
To predict the performance of protective structures, in a preliminary design for weapons effects analysis processes considering the ship vulnerability evaluation, it is important to choose a method which is simple, quick and feasible. This paper presents a semi-empirical method to study the resistant performance of perforation in protective structures for fragment effects, such as residual velocity after penetration of structures between source of explosion and the target. In the calculation procedure, the mass distribution of fragments is obtained by expressing Mott’s equation, the initial and striking velocities are calculated using Gurney’s formulas and the residual velocity is estimated using Baker et al.’s equation. Using experimental results from the literature, Woodward’s test data (1978) and Edwards and Mathewson’s experimental data (1997) are employed to verify the ballistic limit velocity, and Rupert et al’s test data (1997), Sorensen et al’s test data (1999) and Yarin et al’s test data (2000) are adopted to check the residual velocity. An example of a 500-ton patrol-boat’s hull and bulkhead is also discussed. The results of the verification are good in terms of agreement, and impact velocities of this study varies from 1500 m/s to 2000 m/s, the ratio of L/D ranges from 6 to 10 and the ratio (h/D) varies from 2.0 to 11.0, may serve as a useful reference for designers.  相似文献   

8.
The speciation of dissolved iodine and the distributions of the iodine species in the deep Chesapeake Bay underwent seasonal variations in response to changes in the prevailing redox condition. In the deep water, the ratios of iodate to iodide and iodate to inorganic iodine decreased progressively from the Winter through the Summer as the deep water became more poorly oxygenated before they rebounded in the Fall when the deep water became re-oxygenated again. The composition of the surface water followed the same trend. However, in this case, the higher biological activities in the Spring and the Summer could also have enhanced the biologically mediated reduction of iodate to iodide by phytoplankton and contributed to the lower ratios found during those seasons. Superimposed on this redox cycle was a cycle of input and removal of dissolved iodine probably as a result of the interactions between the water column and the underlying sediments. Iodine was added to the Bay during the Summer when the deep water was more reducing and removed from the Bay in the Fall when the deep water became re-oxygenated. A third cycle was the inter-conversion between inorganic iodine and ‘dissolved organic iodine’, or ‘‘DOI’’. The conversion of inorganic iodine to ‘DOI’ was more prevalent in the Spring. As a result of these biogeochemical reactions in the Bay, during exchanges between the Bay and the North Atlantic, iodate-rich and ‘DOI’-poor water was imported into the Bay while iodide- and ‘DOI’-rich water was exported to the Atlantic. The export of iodide from these geochemically reactive systems along the land margins contributes to the enrichment of iodide in the surface open oceans.  相似文献   

9.
10.
This paper analyses the concept of ‘co-management’ and tries to explain why co-management has recently become important to different types of fisheries administration. A preliminary analytical framework is sketched, before going on to describe the Norwegian co-management system, known as ‘centrally directed consultation’, where fishermen's representatives are established on a wide range of organisations that exert a direct influence on fisheries policy, including not only quota management but grant aid, sales, research and education. The final section is devoted to the lessons that may be learned from the Norwegian experience, bearing in mind the particular background of Norway and its historical setting.  相似文献   

11.
Cecil Jones   《Marine Policy》1978,2(4):321-330
Marine archaeology is a new discipline which seeks to increase knowledge of man's past activities on the sea, through the study of the remains of his ships and other relics on the ocean floor. The author argues that marine archaeology, through its combination of techniques taken from marine ecology, geology, sedimentology and other sciences, has evolved to the point in the UK where it may be classified as a science in its own right. He discusses legal and social problems of the field, and points out the need for a ‘systems approach’ in marine archaeological projects.  相似文献   

12.
The relationship between total and chemically labile Fe has been studied in estuarine, coastal and shelf waters of the Gulf of Maine, U.S.A. Measurements of the labile fraction of total Fe, defined by complexation with 8-hydroxyquinoline in 1 h, correlate with the availability of Fe to marine phytoplankton and therefore can be used to estimate Fe availability in seawater. The results show that the relative lability (=labile/total) of Fe in seawater varied both spatially and temporally from near-zero to 100%. Although particulate Fe (>0.45 μm) was generally less labile than dissolved Fe (<0.45 μm), the particulate fraction often contributed substantially to labile Fe concentrations overall. Conversely, as much as 75% of ‘dissolved’ Fe was non-labile, and therefore was probably not available to phytoplankton. In seawater/river-water mixing experiments, aggregation diminished the relative lability of Fe by 30%, even though much of it remained in the ‘dissolved’ fraction. Considering phytoplankton nutrition, these results demonstrate that equating dissolved Fe concentrations with ‘available’ metal can be misleading. Furthermore, the large variability observed in the labile proportion of total Fe in seawater indicates that Fe availability to phytoplankton cannot be estimated by applying fixed lability-ratios to total Fe concentrations.  相似文献   

13.
New England salt marshes are dominated by the supratidal high marsh grass, Spartina patens. This grass forms a nearly planar surface, which makes it highly vulnerable to the predicted regime of accelerated sea-level rise (SLR). If the high marsh cannot keep pace with rising sea level it will be transformed to intertidal environments, leading to unusually rapid coastal evolution. Winter processes such as ice-loading of surface peat may degrade the marsh surface. Large volumes of snow and ice compress peat, resulting in shallow compaction and a net loss of elevation in some areas.On the Webhannet marsh in Maine, a simulated ice compaction experiment indicates that thick ice can compress marsh peat (46 cm simulated ‘ice’ produced 6.9 ± 0.3 mm of compaction; 24 cm ‘ice’ produced 3.0 ± 0.8 mm). Experimental data suggest that ice thicknesses greater than 10 cm depress the marsh surface by 2 mm for each cm of total ice thickness. However, surface elevations rebounded to near-control levels within 2 weeks of the removal of simulated ‘ice’ from the surface of the marsh. Normal winter ice accumulations on New England marshes, therefore, do not appear to be sufficient to permanently compact marsh surface peat and lead to loss in marsh surface elevation.  相似文献   

14.
Geochemical as well as multivariate statistical analyses (PCA) were carried out on 20 crude oil samples from ‘Middle’ Pliocene Production Series (MPPS) of Guneshli-Chirag-Azeri (GCA), Bahar, and Gum Adasi fields in the western South Caspian Basin (SCB). PCA analysis employed to source-specific biomarkers distinguishes the oils into two types one being divided into two sub-types; Type 1 (GCA oils), Type 2A (Bahar field oils) and Type 2B (Gum Adasi field oils). Indirect oil-to-source rock correlations to available source rock data from previous studies suggest that Type 1 oils, located in the Apsheron-Balkhans uplift area, are derived from basinal shales of the Oligocene-Lower Miocene Middle Maikop Formation. Type 2A and 2B oils, located in the Gum-deniz-Bahar-Shakh-deniz trend area, are more likely derived from shelf-edge shales of the Upper Maikop Formation and the Middle-Upper Miocene Diatom Suite, respectively.Biomarker maturity study reveals that Type 1 oils (mean %Rc=0.78) are more mature than Type 2 oils (mean %Rc=0.71). Source rocks, which generated these oils, were at generation depth interval between 5200 m (112 °C) and 7500 m (153 °C) at the time of expulsion. This indicates that the western SCB oils experienced significant long-range vertical migration along the deep-seated faults to accumulate in the MPPS reservoirs. Post-accumulation biodegradation process was only observed in the Guneshli field where bacterial alteration (level 4) began between 4.2 and 2.6 mybp and stopped with the deposition of the overlying impermeable Upper Pliocene Akchagyl Formation. Subsequent light hydrocarbon (C1–C16) charge into the Guneshli fields caused precipitation of asphaltenes, which is evidenced by high resin to asphaltene ratios for the present-day Guneshli oils. Evaporative-fractionation examined using the scheme of [Thompson, 1987] showed high correlations of the ‘aromaticity’ B parameter (=toluene/n-C7) and ‘parafinicity’ F parameter (=n-C7/MCH with the %Rc (maturity) and C27/C29 sterane ratio (organic matter type). This implies that Thompson's approach should be used with caution in the SCB. Among the several mechanisms, rapid and thick deposition of Pliocene sediments and subsequent high heating rate on the Maikop Formation and Diatom Suite is probably the most plausible way of explaining the origin of light hydrocarbons in the Guneshli and Bahar fields.  相似文献   

15.
This occasional column gives details of audio-visual materials which are concerned with marine affairs. They may be useful as educational aids for university or college courses, and as supplementary training materials for ‘maritime managers’ in offshore industries.  相似文献   

16.
A video-based technique for mapping intertidal beach bathymetry   总被引:2,自引:0,他引:2  
Measuring the location of the shoreline and monitoring foreshore changes through time are core tasks carried out by coastal engineers for a wide range of research, monitoring and design applications. With the advent of digital imaging technology, shore-based video systems provide continuous and automated data collection, encompassing a much greater range of time and spatial scales than were previously possible using field survey methods.A new video-based technique is presented that utilises full-colour image information, which overcomes problems associated with previous grey-scale methods, which work well at steep (reflective) sites, but are less successful at flatter (dissipative) sites. Identification of the shoreline feature is achieved by the automated clustering of sub-aqueous and sub-aerial pixels in ‘Hue–Saturation–Value’ (HSV) colour space, and applying an objective discriminator function to define their boundary (i.e., ‘shoreline’) within a time-series of consecutive geo-referenced images. The elevation corresponding to the detected shoreline features is calculated on the basis of concurrent tide and wave information, which is incorporated in a model that combines the effects of wave set-up and swash, at both incident and infragravity frequencies.Validation of the technique is achieved by comparison with DGPS survey results, to assess the accuracy of the detection and elevation methods both separately and together. The uncertainties associated with the two sub-components of the model tend to compensate for each other. The mean difference between image-based and surveyed shoreline elevations was less than 15 cm along 85% of the 2-km study region, which corresponded to an horizontal offset of 6 m. The application of the intertidal bathymetry mapping technique in support of CZM objectives is briefly illustrated at two sites in The Netherlands and Australia.  相似文献   

17.
This study challenges the ‘National Park’ as the appropriate management model for the Peixe Lagoon area in southern Brazil through an investigation of local fisherfolk livelihoods and traditional ecological knowledge. We argue that top-down management policies implemented through a non-participatory process, which have resulted in conflict between government officials and fisherfolk, disregarded the fisherfolk’s cultural practices and particular knowledge, thereby violating their rights as traditional people. Multiple suggestions are provided to achieve environmental conservation schemes without compromising the local traditional fishing livelihoods.  相似文献   

18.
Stratification is perhaps the most important attribute of oceans with regards to climate and biology. Two simple aspects of the ocean's climate system appear to have a surprisingly important role in transforming waters that feed the global thermohaline circulation, dominating patterns of biogeochemical flux and establishing macroecological domains. First, largely because of meridional distillation (mainly due to the atmospheric transport of freshwater across the Isthmus of Panama) the North Pacific is fresher than the North Atlantic. Second, largely because of zonal distillation (e.g., warming and evaporation at low latitudes and poleward transport of latent heat and moisture by the atmosphere) the upper layers of subtropical seas are permanently stratified by temperature (NT2=dT/dz>0; here called alpha oceans), while the upper layers of high-latitude seas are permanently stratified by salinity (NS2=dS/dz>0; here called beta oceans). The physical basis for the boundary separating alpha and beta oceans is unclear, but may lie in the thermodynamical equations published by Fofonoff [1961. Energy transformations in the sea. Fisheries Research Board of Canada, Report Series 109, 82pp]. Nevertheless, it is clear that the resulting thermohaline distributions establish a ‘downhill journey’ of low-salinity (and nutrient-rich) waters from the North Pacific to the Arctic and then into the North Atlantic. The Arctic Ocean—itself—acts a double estuary, whereby waters entering from the North Atlantic become either denser through cooling (negative estuary) or lighter by freshening (positive estuary) as they circulate within the basin and then return to the North Atlantic as a variety of components of the ocean's conveyor. Intermediate and deep waters generally form within cyclonic beta oceans in close proximity to alphas systems. Similar patterns of stratification, nutrients and biogeographical boundaries persist in the Southern Hemisphere. It is thus argued that this simple distinction—alpha versus beta oceans—provides a broad, conceptual framework for simple interpretation of key physical and biological processes and rates, including the impacts of climate variability.  相似文献   

19.
Internationally, shark conservation is now being recognized as a major environmental challenge, but management efforts to halt the overexploitation of sharks have lagged behind. This review examines the state of knowledge for shark species in Canadian waters and analyzes the role of existing management and legislation in ensuring shark conservation. Despite Canada's early leadership, the present management framework reveals major shortcomings with regard to legal protection, bycatch and finning regulations. These problems are not unique to Canada but illustrate broader issues pertaining to the global management of endangered fish species. To strengthen the conservation and management of sharks, this paper recommends a set of key policies and management priorities, which exemplify proper precautionary management of endangered shark species in Canada and could serve as a blueprint for improving conservation efforts internationally. A structured approach for grading progress in shark conservation efforts against best practices is also presented and could be used as a goalpost elsewhere.  相似文献   

20.
A previous paper (Payne, 1980) developed the theory of a slender planing surface from first principles, and found it to agree with experiment without the need for “factors determined from experiments”. The theory broke down, however, for low wetted length to beam ratios because the flow is then no longer two-dimensional in character in respect to a section normal to the flow. It is in a transition to the condition where, at very small length to beam ratios, it is two-dimensional in a vertical plane parallel to the flow, rather than normal to it.In the present paper we determine, albeit somewhat heuristically, the virtual mass coefficient of a flat plate in the transition region. This is then employed to compute the normal force on a planing plate in both steady state and transient motion. For both conditions the agreement with the available experimental data is within the accuracy of the data.Both theory and experiment lead to the conclusion that certain traditional concepts in the of trim angle and Pierson's suggestion that ‘wetted length’ is more fundamental than the length of intersection with the still water surface. The widespread acceptance of this latter suggestion has meant that a key parameter in the present theory—the nominal or undisturbed water intersection length—is almost never measured in modern experiments. Thus, since we could not find any modern data, we had to appeal to the classical experimental papers which originated the scientific study of planing in the thirties and forties. Oddly, the earliest papers gave data which had much less scatter than the later papers.  相似文献   

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