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241.
The EU Marine Strategy Framework Directive (MSFD) is considered to be the environmental pillar of the EU Integrated Maritime Policy, establishing a framework within which member states must take the necessary measures to achieve, or maintain, good environmental status in their marine waters. This study presents Portugal's contributions to the Directive development, describes the Portuguese institutional framework within the MSFD and, finally, highlights the opportunities and threats to the success of the MSFD implementation in Portugal. The latter entails an analysis of the Directive's long term adequacy in its link to (1) marine spatial planning, (2) climate change and (3) the economic/financial crisis. With one of Europe's largest exclusive economic zones. Portugal's interest in the MSFD is paramount. Efforts towards the approval of the final document were assured during the Portuguese presidency of the European Council of Ministers, in 2007, while chairing a thorough discussion between the Council and the European Parliament. In the Portuguese context, the Directive implementation will rely on the Water Institute as the authoritative entity, which will be responsible for coordinating all necessary efforts at the national level. The success of such process depends on a close cooperation among the institutions involved as well as on how approved measures account for long term issues. In addition, the MSFD implementation must be built on lessons learned within the Water Framework Directive, in order to be successful. Although it poses a methodological challenge to Portugal, the MSFD implementation is expected to contribute significantly to the improvement of coastal/marine conservation and management at the national level.  相似文献   
242.
Marine populations in Europe are in decline due to the unsuccessful results of the Common Fisheries Policy. By combining data of scientific recommendations from ICES, TACs approved and reported landings with an age-structured model, the objectives of this paper are to investigate the level of compliance of the TAC regulation, and the level of enforcement and its economic impact on fishery resources. The results presented here suggest that while there does not exist a regular pattern between TAC proposal and TAC approved, there is a clear pattern between TAC approved and reported landings. As a consequence, there is a regular lack of enforcement at national fisheries authority level. The paper also presents results of the recovery plans for the Southern hake and the Atlantic cod fisheries as case studies to illustrate the level of enforcement based on collusion between national fisheries advisers and industry. The results from both cases studies analyzed here indicate that drastic solutions could generate positive results for the recovery of the stocks, but perhaps they are not always the best measure in fisheries management due to the high economic losses for fishermen and social effects on coastal communities in the short and medium term. Finally, this work demonstrates that if the recovery plans had been implemented, the net present profits for both fisheries would have increased over time.  相似文献   
243.
Changes in wandering beetle assemblages (Carabidae and Tenebrionidae) of different habitats situated in coastal wetlands of a Mediterranean arid area (Mar Menor, SE Spain) were analysed in 1984, 1992 and 2003 by pitfall trapping. Over two decades, the increase in irrigated lands at watershed scale led to rising water tables in the Mar Menor wetlands, which affected their beetle communities. These hydrological changes caused an increase in the carabid population, particularly in the sites most affected by flooding, where halobionts and halophiles, which were practically absent in 1984 and 1992, had become dominant by 2003. In contrast, tenebrionid assemblages simplified with time and by 2003 were dominated by one or two generalist species.  相似文献   
244.
Classification of washover dynamics in barrier islands   总被引:1,自引:0,他引:1  
This study systematically classifies washover dynamics with reference to coastal changes along the Ria Formosa barrier islands (Southern Portugal). Identification of washovers using a sequence of 11 sets of aerial photographs dated between 1947 and 2001 allowed a classification to be developed based on: (1) overwash evolution (increasing, decreasing, or constant overwash processes); (2) the mechanisms promoting washover formation (exceptional to infrequent oceanographic conditions, washout processes, structural erosion, inlet dynamics, and human interventions); and (3) the mechanisms promoting washover cessation (berm development, structural erosion, dune development, inlet dynamics, and human interventions). A total of 369 different washovers were observed along the Ria Formosa barriers during the study period, with 209 washovers being formed in various types of dune morphology and 303 being obliterated. The number of washovers was relatively stable from 1947 to 1972, and increased dramatically between 1972 and 1976 probably as a result of the development of immature inlet margins and downdrift starvation. From 1976 to 2001, washover occurrences declined and their spatial dimensions decreased, leading to a decrease in overwash activity over this time. Overall, the dominant formation mechanisms of washovers in the Ria Formosa were inlet dynamics (accounting for 57% of washovers formed) and structural erosion (20%), with human intervention mechanisms accounting for 12%. The cessation of washovers was dominated by dune development (33% of the washovers obliterated) followed by inlet dynamics (24%) and structural erosion (19%), while human intervention mechanisms accounted for 13%. The classification should be of use for the coastal management of barrier systems including the definition of overwash-prone areas and the determination of the relative importance of the mechanisms contributing to washover formation and cessation.  相似文献   
245.
The Castelo dos Sonhos Formation (CSF) represents a relic of a sedimentary basin located in the southeastern Tapajós Gold Province (TGP), at its boundary with the Iriri–Xingu Domain (IX), south of the Amazonian Craton. The formation comprises mature, coarse-grained metasandstones (quartz-arenites) intercalated with auriferous metaconglomerates with clasts of quartz and subordinately of banded iron formation, quartzite, schist, and felsic metavolcanic rocks. Lithology, planar, channelled, and large-scale cross-bedding suggest deposition in continental setting by the braided fluvial system associated with alluvial fans and subordinate aeolian dunes. The rocks underwent very low metamorphism and gently synformal folding, and were intruded by andesites and granitoids (2011–1918 Ma). U–Pb LA-ICP-MS zircon data indicate maximum depositional ages of 2050 Ma (metaconglomerate) and 2074, 2088, and 2104 Ma (metasandstones). Hence, deposition occurred at 2050–2011 Ma, slightly preceding or being coeval with the onset of the orogenic phase in TGP (2030–1956 Ma). The quartz-arenite composition, zircon U–Pb data, and negative εHf (?1.3 to ?13.0) and εNd (?2.9 to ?5.3) values indicate: (1) quartzose provenance, (2) prolonged transport and recycling of sedimentary sources, (3) multiple age peaks (2050–3700 Ma), with predominant sources of 2100 and 2750 Ma, and (4) long crustal residence time for the source rocks. Source areas were Rhyacian–Siderian orogenic belts to Mesoarchaean terranes of the Amazonian Craton located to the east, southeast, and northeast of TGP, along with Palaeoarchaean and Eoarchaean detrital zircons recycled from older sedimentary rocks. We interpret CSF as part of a larger foreland system related to the evolution of Rhyacian orogens, currently represented by the Bacajá and Santana do Araguaia domains. The present location of CSF in the easternmost TGP, close to its boundary with IX, is due to rifting (1.89–1.80 Ga) that produced the Uatumã Silicic Large Igneous Province (Uatumã SLIP), and the juxtaposition of the crustal domains is supported by gravity data.  相似文献   
246.
Iranian strong motion records as well as detailed conditions of their instrument sites and the characteristics of their causative seismic sources are compiled and processed. The dataset consists of 2286 three-component records from 461 Iranian earthquakes with at least two high-quality records having moment magnitude from 3.9 to 7.3. These records are about 20% of the Iranian database and are suitable for seismic hazard analysis and engineering applications. Perhaps for the first time in the literature, the distance to the surface projection of the fault is reported for a great number of records corresponding to earthquakes with M > 6.0. The raw accelerations are processed using the wavelet de-noising method. Having corrected and filtered these raw data, the pseudospectral accelerations are calculated for each of the three components of time series, separately. In addition to the ground motion parameters, a large and comprehensive list of metadata characterizing the recording conditions of each record is also developed. Moreover, careful revision of the characteristics of the earthquakes such as location, magnitude, style of faulting and fault rupture plane geometry, if available, is carried out using the best available information in a scientifically sound manner. Finally, we also focus on special ground motion records including records with peak ground acceleration (PGA) >300 cm/s2 and distances less than 30 km. These are “exceptional” records in the Iranian dataset and include less than 2% of the selected dataset.  相似文献   
247.
The aim of this work was to quantify the biopolymers associated to esterase enzymes and identify bacterial respiratory activity in four cores collected in Suruí Mangrove, Guanabara Bay - RJ. Biopolymer concentration was 1000 times lower than previously reported in the literature, indicating the need for creating and establishing eutrophication indicative rates and records compatible with tropical coastal systems. The biochemical representative relationships in the cores were equivalent to those from studies on coastal marine environments made in the Northern Hemisphere. The esterase enzymes in the sediment proved efficient in the mineralization of biopolymers, even with preferentially anaerobic metabolic physiology. Despite the lack of incipient geomicrobiological studies, the results highlighted the possible application of microbiology to a better understanding of geological processes.  相似文献   
248.
This paper examines the daily morphological responses of Sununga Beach, an embayed beach located on the south‐eastern Brazilian coast, to storms in the South Atlantic Ocean. The main mechanisms and timing of beach erosion and accretion, the relationship between wave height and direction, and beach volume changes are considered, to establish a qualitative model for short‐term embayed beach morphological changes. The methodology consisted of daily topographic surveys during the month of May in 2001, 2002, and 2003, using an RTK‐GPS (real‐time kinematics – global positioning system). Weather and wave model results were used to correlate hydrodynamics and beach morphology. The results indicate that the morphodynamics of Sununga Beach are characterized by a process of beach rotation, which occurred more or less clearly during all three surveys. Unlike what has been commonly described in the literature for longer time intervals and alternations of fair and stormy weather, the beach rotation processes on Sununga Beach occurred under conditions of moderate‐to‐high wave energy change (wave heights greater than 2 m). An integrated evaluation of the behaviour of the meteorological aspects, together with beach morphology, enabled us to recognize that extra‐tropical cyclones were the most important agent in remobilizing the beach planform, whether in beach rotation or in cross‐shore erosion. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   
249.
For certain initial and boundary conditions the Boussinesq equation, a nonlinear partial differential equation describing the flow of water in unconfined aquifers, can be reduced to a boundary value problem for a nonlinear ordinary differential equation. Using Song et al.'s (2007) [7] approach, we show that for zero head initial condition and power-law flux boundary condition at the inlet boundary, the solution in the form of power series can be obtained with Barenblatt's (1990) [2] rescaling procedure applied to the power series solution obtained in Song et al. (2007) [7] for the power-law head boundary condition. Polynomial approximations can then be obtained by taking terms from the power series. Although for a small number of terms the newly obtained approximations may be worse than polynomial approximations obtained by other techniques, any desired accuracy can be achieved by taking more terms from the power series.  相似文献   
250.
This study investigates total petroleum hydrocarbon (TPH) removal from residual clayey soil, after a washing procedure, using an electrokinetic process. Eight electrokinetic experiments were carried out to investigate the characteristics of TPH removal. When 0.1 M MgSO4 or 0.1 M NaOH was used as an electrolyte, the electric current rapidly increased within the first 100 or 200 h, respectively. A negatively charged soil surface resulted in a more negative zeta potential and greater electroosmotic flow toward the cathode. Therefore, the accumulated electroosmotic flow (EOF) when using 0.1 M NaOH as the anolyte‐purging solution was higher than when using 0.1 M MgSO4. Although the energy consumption for the two purging solutions was similar, the efficiencies of TPH removal when 0.1 M MgSO4 and 0.1 M NaOH with surfactant were used were 0 and 39%, respectively, because the electroosmotic flow rate increased with TPH removal efficiency. When 5% isopropyl alcohol (IPA) was used as a circulation solution, the electric current increased but the TPH removal was similar to that using water. In terms of energy consumption, the use of a surfactant‐enhanced electrokinetic process with NaOH as electrolyte was effective in removing TPHs from low‐permeability soil.  相似文献   
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