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221.
Mercury emissions from forest fires in countries bordering the Mediterranean Sea have been estimated on the basis of satellite observations for the year 2006. The assessment has been done by means of the Moderate Resolution Imaging Spectroradiometer (MODIS) products (MOD12Q1, MOD14A2, MOD15A2, MOD44B). Estimates show that wild fires have burnt 310,268 ha in the Region, affecting by 45% the Mixed Forest and by 37% the Evergreen Needleleaf Forest and the Evergreen Broadleaf Forest. The amount of biomass burned was about 66,000 Mg for the Evergreen Needleleaf Forest, 72,000 Mg for the Evergreen Broadleaf Forest and 196,000 Mg for the Mixed Forest. The total amount of mercury released to the atmosphere in the Mediterranean countries accounted for 4.3 Mg year−1 with Italy, France, Austria, Bulgaria, Algeria, Spain and Croatia being the most contributing countries with annual emission ranging from 330 to 970 kg year−1. The maximum release of Gaseous Elemental Mercury (GEM) and particulate mercury (Hg(p)) in the region occurred in July with 1,218 kg. The uncertainty of our estimates is comparable with that associated to current assessments of mercury emissions from major industrial sources.  相似文献   
222.
Navarrete SA  Broitman BR  Menge BA 《Ecology》2008,89(5):1308-1322
Recruitment variation can be a major source of fluctuation in populations and communities, making it difficult to generalize results. Determining the scales of variation and whether spatial patterns in the supply of individuals are persistent over time can provide insight into spatial generality and the application of conservation and metacommunity models. We examined these issues using eight-year-long data sets of monthly recruitment of intertidal mussels (Mytilus spp., Perumytilus purpuratus, Semimytilus algosus, Brachidontes granulata) and barnacles (Balanus glandula, Chthamalus dalli, Jehlius cirratus, Notochthamalus scabrosus) at sites spanning > 900 km along the coasts of Oregon-northern California (OR-NCA, 45.47-39.43 degrees N) and central Chile (CC, 29.5-34.65 degrees S). We evaluated four general "null" hypotheses: that despite different phylogenies and great spatial separation of these taxa, their similar life history strategies and environmental settings lead to similar patterns of recruitment (1) between hemispheres, (2) in time, (3) in space, and (4) at larger and smaller spatial scales. Hypothesis 1 was rejected: along the OR-NCA coast, rates of recruitment were between two and three orders of magnitude higher, and patterns of seasonality were generally stronger and more coherent across space and time than along CC. Surprisingly, however, further analysis revealed regularities in both time and space for all species, supporting hypotheses 2 and 3. Temporal decorrelation scales were 1-3 months, and characteristic spatial scales of recruitment were approximately 250 km. Contrary to hypothesis 4, for the ecologically dominant species in both hemispheres, recruitment was remarkably persistent at larger mesoscales (kilometers) but was highly stochastic at smaller microscales (meters). Across species, increased recruitment variation at large scales was positively associated with increased persistence. Our results have several implications. Although the two regions span distinct latitudinal ranges, potential forcing processes behind these patterns include similar large-scale climates and topographically locked hydrographic features, such as upwelling. Further, spatial persistence of the recruitment patterns of most species at the mesoscale supports the view that marine protected areas can be powerful conservation and management tools. Finally, persistent and yet contrasting spatial patterns of recruitment among competing species suggest that recent metacommunity models might provide useful representations of the mechanisms involved in species coexistence.  相似文献   
223.
224.
The present work proposes a siting process for the detection of a suitable site for wave energy exploitation. The choice of a suitable site is based on the good agreement between energy availability, environmental sustainability, and equipped facilities to exploit wave energy. The case study in the northern Latium coast is explicative because in this area there are several activities that affect marine ecosystems, and the introduction of renewable energies promote the reduction of anthropic pressures. The nearshore wave power is studied through the numerical wave model (CMS-Wave), and available wave buoys along the coast were used to compare numerical results. In correspondence with Civitavecchia harbour, the largest nearshore wave energy was found; the large depth in front of the breakwater allows to conserve a great part of offshore wave power, with an average dissipation rate of 10 % less than offshore, with mean annual available wave energy of 25.4 MWh/m and seasonal fluctuation of 5.4 MWh/m. This area appears to be an optimal site for nearshore and shoreline wave energy device tests and installations, for energy availability (intermediate level respect Mediterreanean Sea), low potential environmental impact, easier accessibility, and policy oriented towards a larger sustainability of harbour activities.  相似文献   
225.
The curculionid beetle Naupactus bipes (Germar, 1824) (Coleoptera: Curculionidae: Brachycerinae) has shown feeding preference for leaves of Piper gaudichaudianum, demonstrating an unexpected specificity for an insect considered to be a generalist. The leaves of P. gaudichaudianum contain the prenylated chromenes gaudichaudianic acid (4, major compound) and its methyl ester (5) in addition to a chromene (3) lacking one prenyl residue. In addition to 4, roots contain the chromone methyl ester (1) and methyl taboganate (2, major compound). Feeding on roots, larvae of N. bipes sequester exclusively the root-specific compounds 1 and 2. Adult beetles sequester the leaf-specific chromenes 3 and 4, but were found to also contain compounds 1 and 2 that are absent in leaves. Therefore, it is suggested that 1 and 2 are sequestered by larvae and can be found in the body of adult insects after long-term storage. In addition, 3 and 4, the major compounds in leaves were found to be associated with the eggs.  相似文献   
226.
In this study, we show that moonmilk subaerial speleothems in Altamira Cave (Spain) consist of a network of fiber calcite crystals and active microbial structures. In Altamira moonmilks, the study of the typology and distribution of fiber crystals, extracellular polymeric substances, and microorganisms allowed us to define the initial stages of fiber crystal formation in recent samples as well as the variations in the microstructural arrangement in more evolved stages. Thus, we have been able to show the existence of a relationship among the different types of fiber crystals and their origins. This allowed us to outline a model that illustrates the different stages of formation of the moonmilk, developed on different substrata, concluding that microbes influence physicochemical precipitation, resulting in a variety of fiber crystal morphologies and sizes.  相似文献   
227.
Benthic suspension feeders are abundant in Mediterranean coastal environments, though most of them are threatened due to overexploitation, climate change impacts, and unregulated diving or fishing practices. Little is known about most of the coastal communities in terms of large-scale distribution and realistic benthic–pelagic coupling implications, which are keys to understand and manage those threatened ecosystems. The active suspension feeder Halocynthia papillosa (one of the most common ascidian species of the Mediterranean Sea) was selected as a model organism to help to understand the ecological role in benthic–pelagic coupling processes and its importance as a carbon sink (an essential ecosystem service). The spatial and bathymetrical distribution of this organism has been studied using remotely operated vehicle video transects. The species was distributed throughout the study area, with a maximum density of 4 specimens m?2. The highest abundances and the biggest sizes were observed on the range of 20–50 m depth. The role as carbon and nitrogen sink of this suspension feeder has been quantified coupling distribution data with existing in situ studies of feeding and respiration. Along the 1.24 ha of the study area, H. papillosa yearly ingested 519.4 g C and 31.4 g N and retained 20.2 g C. As long as the physiological data are known, this new methodology could be very useful in assessing bentho–pelagic links and the capacity of being C and N sinks of a wide range of species. This new approach may be essential for the future management of benthic communities.  相似文献   
228.
The quality of the waters collected from R. Arno was examined in the period September 1988 to December 1989. A first campaign in September/October 1988, during a period of low water, gives a general picture of pollution conditions along the river from the source to the mouth. the river appears to be heavily polluted immediately downstream of Florence and in the area of the textile industry.

In the second campaign, through the whole year 1989, particular attention has been given to the Florence area; the most significant results, compared with those from a previous investigation carried out in 1971, show only a small reduction of the pollution load, due to the shortage and inadequacy of wastewater depuration. Some considerations are reported on pollution drop with full spate.  相似文献   
229.
Nutrients (ammonium‐nitrogen, nitrite, nitrate, orthophosphate and dissolved silica) as well as some chemical‐physical parameters (temperature, pH, salinity, dissolved oxygen and total suspended matter) were determined in filtered seawater samples taken at the surface, at middle depth and at the bottom, in 6 open‐sea locations of the Gulf of Trieste (northern Adriatic Sea) close to pipeline exits that discharge wastewaters from treatment plants. The collected data allow a comparison of the quality of these open‐sea waters with coastal waters and constitute a reference for successive monitoring in these locations suspected of pollution. A multivariate statistical analysis by the principal component method shows that the considered ecosystem can be modeled with two factors: the first one is referenced to the marine environment, in particular to the decomposition of the organic debris in deep water; whereas the second factor is referenced to the input of freshwaters in the Gulf, driving nitrates from agricultural lands.  相似文献   
230.
Prenatal diagnosis of sickle cell diseases has been available for several years, and our laboratory has performed over 1000 prenatal diagnoses. However, currently available techniques are labor-intensive and time-consuming, and thus the diagnosis is delayed, making the mother's decision difficult. We describe a rapid, high-throughput technique based on the ligation assay coupled with automated capillary fluorescence detection. This new approach allows the diagnosis of both Hgb S and Hgb C to be available in a few hours. We have utilized this technique in 30 prenatal diagnoses and found it to be in complete agreement with the standard diagnoses. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
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