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排序方式: 共有215条查询结果,搜索用时 31 毫秒
181.
Celia Ojeda-Martínez Francisca Giménez Casalduero Just T. Bayle-Sempere Carmen Barbera Cebrián Carlos Valle Jose Luis Sanchez-Lizaso Aitor Forcada Pablo Sanchez-Jerez Pablo Martín-Sosa Jesús M. Falcón Fuensanta Salas Mariagrazia Graziano Renato Chemello Ben Stobart Pedro Cartagena Angel Pérez-Ruzafa Fréderic Vandeperre Elisabeth Rochel Serge Planes Alberto Brito 《Ocean & Coastal Management》2009,52(2):89-101
A general conceptual framework for the management of marine protected areas (MPAs) was developed. The driver-pressure-state-impacts-response (DPSIR) framework was used to determine the elements affecting MPAs. The developed evaluation framework helped to select an appropriate suite of indicators to support an ecosystem approach, an assessment of the MPAs functioning and policy decisions. Gaps derived from the management and policy responses in the MPAs were also outlined. It was concluded that the DPSIR framework can help to simplify the complexity of MPA management. This document is a tool for policy makers, scientists and general public on the relevance of indicators to monitor changes and MPAs management. 相似文献
182.
Carmen Morales-Caselles Inmaculada Riba T. Ángel DelValls 《Marine environmental research》2009,67(1):31-37
In an attempt to incorporate both line of evidence (LOE) and classical weight of evidence (WOE) approaches for the assessment of sediment quality, a set of biomarkers were analyzed in target tissues of two invertebrate species after 28 days of exposure to sediments impacted by oil (derived from the tanker Prestige (2002)). The integration of biomarkers with sediment contamination, acute toxicity and benthic alteration parameters provides an “early warning” tool which not only indicates the environmental quality of an area, but also constitutes an advisory tool for potential ecological risks. The selected biomarkers provide information about the first biological responses due to the presence of contaminants in the environment providing predictable reports about further effects to the ecosystem. The present study demonstrates that the use of a set of biomarkers as part of a WOE approach designed to assess contaminated sediments contributes added value to the classical LOE and allows characterization of the environmental status of the studied area in a more precise and accurate way. 相似文献
183.
Jesús M. Mercado Carmen B. de los Santos J. Lucas Pérez-Lloréns Juan J. Vergara 《Estuarine, Coastal and Shelf Science》2009
The 13C signature of forty-five macroalgal species from intertidal zones at Cádiz Bay was analysed in order to research the extension of diffusive vs. non-diffusive utilisation of dissolved inorganic carbon (DIC) and to perform a comparison with data published for other bio-geographic regions. The ∂13C values ranged from −6.8‰ to −33‰, although the span of variation was different depending on the taxa. Thus, ∂13C for Chlorophyta varied from −7‰ (Codium adhaerens) to −29.6‰ (Flabellia petiolata), while all the Phaeophyceae (excepting Padina pavonica with ∂13C higher than −10‰) had values between −10‰, and −20‰. The widest variation range was recorded in Rhodophyta, from values above −10‰ (Liagora viscida) to values lower than −30‰ obtained in three species belonging to the subclass Rhodymeniophycidae. Accordingly, the mean ∂13C value calculated for red algae (−20.2‰) was significantly lower than that for brown (−15.9‰) and green algae (−15.6‰). Most of the analysed red algae were species inhabiting crevices and the low intertidal fringe which explains that, on average, the shaded-habitat species had a ∂13C value lower than those growing fully exposed to sun (i.e. in rockpools or at the upper intertidal zone). The comparison between the capacity for non-diffusive use of DIC (i.e. active or facilitated transport of HCO3− and/or CO2) and the ∂13C values reveals that values more negative than −30‰ indicate that photosynthesis is dependent on CO2 diffusive entry, whereas values above this threshold would not indicate necessary the operation of a non-diffusive DIC transport mechanism. Furthermore, external carbonic anhydrase activity (extCA) and ∂13C values were negatively correlated indicating that the higher the dependence of the photosynthesis on the CO2 supplied from HCO3− via extCA, the lower the ∂13C in the algal material. The comparison between the ∂13C values obtained for the analysed species and those published for species inhabiting other bio-geographic areas (warm-temperate, cold and polar) suggests that globally (at least for the red and brown algae) the non-diffusive entry of DIC is more widely spread among the species from Cádiz Bay than among those of polar regions. If it is assumed that non-diffusive use of DIC implies saturation of photosynthesis at the present-day CO2 concentration in seawater, our data indicate that the potential impact of the acidification on photosynthesis in the seaweed communities will be different depending on the latitude. 相似文献
184.
A steep‐margined carbonate platform is developed in the Carboniferous synorogenic foreland basin of northern Spain. Dips of 60–90° produced during Late Carboniferous thrusting enable cross‐sections of a 4‐km‐wide portion of the marginal area of this platform (Las Llacerias outcrop) to be studied in aerial photographs at a seismic scale. Three stratal domains are observed: (1) a horizontal‐bedded platform; (2) a clinoformal‐bedded margin with a relief of up to 500 m; and (3) a low‐angle toe‐of‐slope, where slope beds interfinger with basin sediments. The slope shows well‐bedded sigmoidal clinoforms with depositional dips ranging from 15° to 32°. Based on lithology and stratal patterns, four facies groups have been recognized: (1) a flat‐topped platform, in which thick algal boundstone, skeletal packstone–grainstone and peloidal micrite wackestone with a poorly rhythmic character prevail; (2) the platform margin and upper slope, characterized by microbial boundstone spanning a bathymetric range of ≈150 m measured from the break of slope; (3) a slope, predominantly composed of margin‐derived rudstones and breccias; and (4) a toe‐of‐slope to basin zone, where a cyclic alternation of spiculitic siltstones, packstone to grainstone calciturbidites and rudstone/breccia is visible. Five successive stages of platform development are deduced: (1) Bashkirian: flooding of the pre‐existing Serpukhovian platform giving rise to the nucleation of a low‐angle ramp to the south‐east of the study area with microbial mud‐mound accumulations, and breccias and calciturbidites on the margins; (2) Early Moscovian: an influx of siliciclastic sediment buried part of the platform and reduced the area of carbonate sedimentation; (3) Moscovian: aggradation and progradation of the carbonate system produced an extensive steep‐margined and flat‐topped shallow‐water platform (shelf system); (4) Latest Moscovian–earliest Kasimovian: drowning of the platform; and (5) Kasimovian: covering of the platform by marly calcareous ramp sediments. 相似文献
185.
Peter Ergenzinger Carmen de Jong Berlin Environmental Research Group Institut fur Geographische Wissenschaften Freie Universitut Berlin Grunewaldstr. Berlin Germany 《国际泥沙研究》1997,(3)
LIN~DUCTIONTheinvenigationsofrivermorphologyandOfriverbeddebilityresultalwaysinidalsabouttheinterrelationshipbetweenthehydrauliccondihons,sc(hant~rtandbeddynndcs.ThedeCOuragingfactforsuchinveedgationsarethecomplexityoftheseSystemsandthehugenumberofimportantvariables.IfwefollowSimonsetal(1965)andall~eneeandtheconcentrationsofSUSPendedlOadandbedloadthefollowingparametersarethepnncapleVarialllesf-av~velocityofnow,diStributionofnowvelociticsacdeadofturbulence-meandepthacthedistributionofde… 相似文献
186.
The purpose of this note is to estimate the accuracy and practical limitations of applying linear theory at a critical level over a realistic range of atmospheric stabilities for an idealized surface terrain. These estimates are made by comparing the results of a linear model with a nonlinear numerical model at a critical level. Essentially similar results are obtained from each model for wave stress, wave breaking height and wave dissipation through the critical level. Because gravity waves can be either evanescent or internal depending on the relative sizes of the Scorer parameter and the wavenumber of the ground surface disturbance, the somewhat paradoxical result develops that wave breaking and non-linearity increase with increasing bulk Richardson number. It is recommended that steady linear wave theory be used in gravity wave drag parameterizations provided near real time profiles of background velocity and temperature are available. 相似文献
187.
188.
This paper analyses local differences in access to basic health services in the province of Teruel (Spain), one of the most sparsely populated areas in Europe. The demographic decline and the concentration of the remaining population in the main settlements has meant that there is a high degree of spatial fit of supply and demand and average aggregate accessibility is good. However, access costs are high for the scarce and aged population resident in the most remote villages and hamlets scattered over an extensive and tacitly ignored territory. In such circumstances the demands of the inhabitants for more attention from the public authorities, expressed through the 'Teruel Exists' movement, can be readily understood. 相似文献
189.
The study of climatic anomalies on the basis of various types of instrumental information and proxy-data allows unusual events to be identified. The objective of this paper is to introduce and explain a hydrometeorological anomaly that occurred between 1760 and 1800 (Maldá Anomaly), characterised by a sequence of both anomalous droughts and floods, and to compare it with the features of the second part of the 20th century. Firstly, some climatic indices obtained from proxy-data (mainly documentary sources) have been generated. Secondly, instrumental observations made in earlier times, in conjunction with data from the bibliography, have been used in order to relate this period to the different circulation patterns and to analyse the geographical extension of the anomaly. The results confirm the presence of considerable variations in the atmospheric action centres, especially between 1780 and 1795, which in the Western Mediterranean gave rise to a simultaneous increase in the frequency of droughts and heavy rainfalls, either having nothing comparable or sharing similarities with periods in the 19th and 20th centuries. 相似文献
190.
Carmen Morales José F. Gómez Joaquín Trapero Stuart Bowyer Jerry Edelstein Eric Korpela 《Astrophysics and Space Science》1998,263(1-4):393-396
EURD (Espectrógrafo Ultravioleta extremo de Radiación Difusa), one of the instruments onboard the Spanish satellite MINISAT-01,
is a spectrograph specially designed to detect diffuse radiation, covering the wavelength range of 350-1100 Å, with a spectral
resolution of 6-8 Å. Its main scientific objectives are the detection of the emission line spectrum from the hot phase of
the interstellar medium and the spectrum of the upper atmospheric airglow. In order to reduce geocoronal noise, EURD always
observes in the anti-sun direction and only when the satellite is in orbital eclipse. After more than one year of observation
we have obtained the best spectrum of the upper atmospheric nightglow in this wavelength range, the spectrum of 15 OB stars
and the spectrum of the full Moon throughout the year.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献