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851.
Miralles J Véron AJ Radakovitch O Deschamps P Tremblay T Hamelin B 《Marine pollution bulletin》2006,52(11):1364-1371
Six marine sediment cores from the Gulf of Lions continental slope (700-1700 m water depth) were analyzed for stable lead isotopes and (210)Pb geochronology in order to reconstruct lead atmospheric fallout pattern during the last century. The detrital lead contribution is 25 microg g(-1) and the mean sediment anthropogenic inventory is 110+/-7 microg cm(-2), a little bit higher than atmospheric deposition estimate. Anthropogenic lead accumulation in sediments peaked in early 1970s (1973+/-2) in agreement with lead emissions features. For the period 1986-1997, the sediment signal also reflect the decrease of atmospheric lead described by independent atmospheric fallout investigations. The anthropogenic Pb deposition in the late 1990s was similar to the 1950s deposition, attesting thus of the output of European environmental policies. 相似文献
852.
Panigada S Pesante G Zanardelli M Capoulade F Gannier A Weinrich MT 《Marine pollution bulletin》2006,52(10):1287-1298
This paper reviews and analyzes ship collision records for the relatively isolated population of fin whales in the Mediterranean Sea from 1972 to 2001. Out of 287 carcasses, 46 individuals (16.0%) were certainly killed by boats. The minimum mean annual fatal collision rate increased from 1 to 1.7 whales/year from the 1970s to the 1990s. Fatal strike events (82.2%) were reported in or adjacent to the Pelagos Sanctuary, characterized by high levels of traffic and whale concentrations. Among 383 photo-identified whales, 9 (2.4%) had marks that were attributed to a ship impact. The reported rates are unusually high for baleen whales. The high likelihood of unreported fatal strikes combined with other anthropogenic threats suggests an urgent need for a comprehensive, basin-wide conservation strategy, including ship strike mitigation requirements, like real-time monitoring of whale presence and distribution to re-locate ferry routes to areas of lower cetacean density, and reducing ship speed in high cetacean density areas. 相似文献
853.
HAB occurrence is becoming more frequent and problematic in marine recreational waters. However, the exploitation of the coastal area for recreational use is promoting the necessary conditions for the HAB increase. In terms of the harmful effects, we can consider two types of causative organism: the toxic producers and the high-biomass producers. Toxic events can be produced by a very low concentration of the causative organism. This characteristic implies a difficulty for the monitoring programs in relation to human health. It is important to point out in the context of human health and HAB events, that in some coastal regions (e.g. the Mediterranean basin) HABs are an emerging problem. In these regions, the local population and visitors may face a health risk that is difficult to measure. The monitoring of toxic species has mainly been associated -with shellfish farming. However, the risk of intoxication could become even greater in areas not subject to legislation of aquaculture activities. 相似文献
854.
Are Taxonomic Distinctness measures compliant to other ecological indicators in assessing ecological status? 总被引:1,自引:0,他引:1
Salas F Patrício J Marcos C Pardal MA Pérez-Ruzafa A Marques JC 《Marine pollution bulletin》2006,52(7):817-829
Assessing the ecological status, a concept implemented in the European Water Framework Directive [EC, 2000. Directive of the European Parliament and of the Council 2000/60/EC establishing a framework for community action in the field of water policy PE-CONS 3639/1/00, p. 72], requires the application of methods capable of distinguishing different levels of ecological quality. The Average Taxonomic Distinctness has been used as tool in this context, and we tested the robustness of Taxonomic Distinctness measures applying it in different scenarios (estuarine eutrophication, organic pollution, and re-colonisation after physical disturbance), analysing simultaneously its compliance to other types of ecological indicators. Results show that, in most of the case studies, only Total Taxonomic Distinctness was relatively satisfactory in discriminating between disturbed situations. Other Taxonomic Distinctness measures have not proved to be more sensitive than other ecological indicators (Shannon-Wiener, Margalef, and Eco-Exergy indices). Therefore, this approach does not seem to be particularly helpful in assessing systems' ecological status with regard to the WFD implementation. 相似文献
855.
We describe one-dimensional (1D) simulations of the countergradient zone of mean potential temperature observed in the convective boundary layer (CBL). The method takes into account the third-order moments (TOMs) in a turbulent scheme of relatively low order, using the turbulent kinetic energy equation but without prognostic equations for other second-order moments. The countergradient term is formally linked to the third-order moments and , and a simple parameterization of these TOMs is proposed. It is validated for several cases of a dry CBL, using large-eddy simulations that have been realized from the MESO-NH model. The analysis of the simulations shows that TOMs are responsible for the inversion of the sign of in the higher part of the CBL, and budget analysis shows that the main terms responsible for turbulent fluxes and variances are now well reproduced. 相似文献
856.
Franco MA Viñas L Soriano JA de Armas D González JJ Beiras R Salas N Bayona JM Albaigés J 《Marine pollution bulletin》2006,53(5-7):260-271
The distribution of aliphatic and aromatic hydrocarbons was determined in surface sediments collected at 36 stations along the Galicia continental shelf (NW Spain), following the Prestige oil spill. Sampling was performed in December 2002, just after the accident, and in February and September 2003. Concentrations of PAHs (summation operator 13 parent components) were in the range of 0.9-422 microg/kgdw, the highest values being close to coastal urban areas (e.g. Pontevedra and A Coru?a), whereas in the stations of the area most heavily impacted by the spill (off Costa da Morte) concentrations were in the range of 14.8-89.6 microg/kgdw, with a certain predominance of alkylated compounds, which may suggest a mixture of petrogenic and pyrolytic sources. The detailed study of petrogenic molecular markers (e.g. steranes and triterpanes) showed the occurrence of an old (weathered) petrogenic chronic pollution in the shelf sediments but not of the Prestige oil, with the possible exception of few stations in the area of Costa da Morte. This was attributed to the heavy nature of the spilled oil that was barely dispersed in the water column and mainly stranded on the coast or sedimented in the form of oil patches. The addition of increasing amounts of fuel oil to a representative sediment sample showed that the molecular indices were indicative of the presence of the Prestige oil when the amount was above 1g/kg of sediment. The toxicity of selected samples (showing the higher PAH concentrations) was tested using the bivalve embryogenesis bioassay. Embryogenesis success reached high values in all cases (80-88%, with 86% in the control), indicating a lack of toxicity in the sediments and supporting the conclusion that the patchiness of the fuel eventually reaching the seafloor reduced its impact on the benthic communities of the Galician shelf. 相似文献
857.
858.
Carracedo P Torres-López S Barreiro M Montero P Balseiro CF Penabad E Leitao PC Pérez-Muñuzuri V 《Marine pollution bulletin》2006,53(5-7):350-360
An integrated system named METEOMOHID, developed by MeteoGalicia in the first stage of the Prestige accident in November 2002 was used successfully in an operational form to support decision making and assist in recovering tasks. Afterwards, METEOMOHID has been enhanced with the aim of developing an operational oceanography system to be used in the NW of the Iberian Peninsula. The METEOMOHID system includes local area hydrodynamic coastal ocean modelling (MOHID), real time atmospheric forcing from a local meteorological model (ARPS). Using the available data from the Prestige crisis, a set of simulations were designed in order to reproduce the oil spill drift. The implementation of a detailed vertical resolution in the model has allowed obtaining a detailed surface dynamic, improving our knowledge of the behaviour of tarballs into the water column. Thus, the wind-driven Eckman drift, the direct dragging of the wind were detached, and the possible existence of subsurface oil was assessed. In addition, the present work evaluates the effects of introducing climatologic large scale currents in the METEOMOHID system. 相似文献
859.
The Las Cañadas caldera wall and the outer slopes of the caldera provide three-dimensional exposures of numerous proximal-welded fallout deposits and have been mapped in detail. As a result, some parts of the Ucanca and Guajara Formations of the stratigraphy of Martí et al. (1994) have been divided into members that correspond to individual eruptions. Mapping has also revealed the occurrence of conduit-vent structures associated with proximal-welded fallout deposits. Conduit-vent structures consist of an upper flaring area and a lower narrow conduit. Conduit-vent geometry and dimensions include cylindrical plugs and eruptive fissures steeply dipping towards the caldera depression and elongated vents. The flaring area can be rather asymmetric and is usually filled by down-vent rheomorphic flow of the proximal fallout deposit. The lower conduits are filled by lava plug, agglutination of juveniles onto conduit walls and dyke intrusion with eventual dome extrusion. The eruption dynamics of welded fallout deposits and magma fragmentation within the conduit are consistent with an evolution from explosive to effusive. In this context conduit flow regimes evolve from turbulent to annular flow in which the conduit is progressively choked, and laminar flow leading to the final conduit closure. 相似文献
860.
Ilhem Bentaleb Cyril Langlois Céline Martin Paula Iacumin Matthieu Carré Pierre-Olivier Antoine Francis Duranthon Issam Moussa Jean-Jacques Jaeger Nicholas Barrett Ron Kandorp 《Comptes Rendus Geoscience》2006,338(3):172-179
The relationship between the oxygen isotope ratio of mammal tooth enamel and that of drinking water was used to reconstruct changes in the Miocene oxygen isotope ratio of rainfall (meteoric water OMW). These, in turn, are related to climatic parameters (temperature, precipitation and evaporation rate). O values of rhinocerotid teeth from the Aquitaine Basin (southwestern France) suggest a significant climatic change between 17 and 12 Ma, characterized by cooling together with precipitation increase, in agreement with other terrestrial and oceanic records. To cite this article: I. Bentaleb et al., C. R. Geoscience 338 (2006). 相似文献