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71.
The model of Paillard and Parrenin (Earth Planet Sci Lett 227(3–4):263–271, 2004) has been recently optimized for the last eight glacial cycles, leading to two different relaxation models with model-data correlations between 0.8 and 0.9 (García-Olivares and Herrero (Clim Dyn 1–25, 2012b)). These two models are here used to predict the effect of an anthropogenic CO 2 pulse on the evolution of atmospheric CO 2, global ice volume and Antarctic ice cover during the next 300 kyr. The initial atmospheric CO 2 condition is obtained after a critical data analysis that sets 1300 Gt as the most realistic carbon Ultimate Recoverable Resources (URR), with the help of a global compartmental model to determine the carbon transfer function to the atmosphere. The next 20 kyr will have an abnormally high greenhouse effect which, according to the CO 2 values, will lengthen the present interglacial by some 25 to 33 kyr. This is because the perturbation of the current interglacial will lead to a delay in the future advance of the ice sheet on the Antarctic shelf, causing that the relative maximum of boreal insolation found 65 kyr after present (AP) will not affect the developing glaciation. Instead, it will be the following insolation peak, about 110 kyr AP, which will find an appropriate climatic state to trigger the next deglaciation. 相似文献
72.
M. García-Sánchez A. Paradiso I. García-Romera E. Aranda M. C. de Pinto 《International Journal of Environmental Science and Technology》2014,11(1):21-32
The disposal of dry olive-mill residue, the waste product from olive oil production, is a serious environmental issue. Dry olive-mill residue, being rich in organic and inorganic nutrients, could be used as fertilizer; however, it contains phenolic compounds that can inhibit plant growth. In order to clarify whether bioremediation of this waste could be a valuable strategy for its reuse, the effect of aqueous extract of dry olive-mill residue, untreated or bioremediated by the saprobe fungi Coriolopsis rigida and Penicillium chrysogenum-10, has been analyzed in relation to some physiological parameters of tomato plants. The data show that aqueous dry olive-mill residue significantly reduces the biomass of roots and shoots. In particular, it causes a dramatic reduction in root length, area, and volume as well as in the number of root tips. At an early stage, aqueous dry olive-mill residue also reduces the content of chlorophyll a and b and the efficiency of PS II. The inhibition of growth seems to be due to the increase in phenolic compounds that induce oxidative stress. Interestingly, when plants are treated with aqueous dry olive-mill residue bioremediated by saprobe fungi a decrease in phenolic content and an alleviation of oxidative stress occur. In conclusion, the results show that bioremediation of aqueous dry olive-mill residue is a useful tool to remove most of the inhibiting effects of this waste on plant growth. 相似文献
73.
Maya P. Bhatt William H. McDowell Kevin H. Gardner Jens Hartmann 《Environmental Earth Sciences》2014,71(2):911-922
Water quality in less-developed countries is often subject to substantial degradation, but is rarely studied in a systematic way. The concentration and flux of major ions, carbon, nitrogen, silicon, and trace metals in the heavily urbanized Bagmati River within Kathmandu Valley, Nepal, are reported. The concentrations of all chemical species increased with distance downstream with the exceptions of protons and nitrate, and showed strong relationships with population density adjacent to the river. Total dissolved nitrogen (TDN), dominated by NH4, was found in high concentrations along the Bagmati drainage system. The export of dissolved organic carbon (DOC) and TDN were 23 and 33 tons km?2 year?1, respectively, at the outlet point of the Kathmandu Valley, much higher than in relatively undeveloped watersheds. The cationic and silica fluxes were 106 and 18 tons km?2 year?1 at the outlet of the Bagmati within Kathmandu Valley, and 36 and 32 tons km?2 year?1 from the relatively pristine headwater area. The difference between headwaters and the urban site suggests that the apparent weathering flux is three times higher than the actual weathering rate in the heavily urbanized Bagmati basin. Fluxes of cations and silica are above the world average, as well as fluxes from densely populated North American and European watersheds. End-member composition of anthropogenic sources like sewage or agricultural runoff is needed to understand the drivers of this high rate of apparent weathering. 相似文献
74.
Francisco Carreño Conde Sandra García Martínez Javier Lillo Ramos Raquel Fernández Martínez Ariana Mabeth-Montoya Colonia 《Environmental Earth Sciences》2014,71(1):61-66
Water resources management of protected sites requires a powerful tool to analyze the process and changes that are occurring in the environment. This paper describes a 3D geomodel design of the Jarama River Detrital Aquifer located in Madrid (Spain). That hydrogeological unit is included in the “Parque Regional de los Cursos Bajos de los Ríos Manzanares y Jarama” (Regional Park of the Lower Courses of Manzanares and Jarama Rivers). The goal of this work is to define a method by which a three-dimensional (3D) model can be created with hydrogeologic geometry real of main aquifer, to accomplish an adequate management of the groundwater resources. All data used in this study were integrated in a geographic database: geological and hydrogeological information, geological map (1:25,000), eleven cross-sections, piezometric maps and a digital elevation model. The constructed 3D model of the Jarama Aquifer shows geometric features and spatial distribution and variations of geologic units. Thus, the 3D model allows the assessment of volumes of each unit, the depth and thickness variations of the main aquifer, and the spatial and temporal variations of water tables. From the 3D model, the most suitable areas (in terms of groundwater protection) for managed recharge and mining works have been identified. 相似文献
75.
76.
Miguel A. García José A. Alloza Ángeles G. Mayor Susana Bautista Francisco Rodríguez 《Central European Journal of Geosciences》2014,6(1):112-120
Moderate resolution remote sensing data, as provided by MODIS, can be used to detect and map active or past wildfires from daily records of suitable combinations of reflectance bands. The objective of the present work was to develop and test simple algorithms and variations for automatic or semiautomatic detection of burnt areas from time series data of MODIS biweekly vegetation indices for a Mediterranean region. MODIS-derived NDVI 250m time series data for the Valencia region, East Spain, were subjected to a two-step process for the detection of candidate burnt areas, and the results compared with available fire event records from the Valencia Regional Government. For each pixel and date in the data series, a model was fitted to both the previous and posterior time series data. Combining drops between two consecutive points and 1-year average drops, we used discrepancies or jumps between the pre and post models to identify seed pixels, and then delimitated fire scars for each potential wildfire using an extension algorithm from the seed pixels. The resulting maps of the detected burnt areas showed a very good agreement with the perimeters registered in the database of fire records used as reference. Overall accuracies and indices of agreement were very high, and omission and commission errors were similar or lower than in previous studies that used automatic or semiautomatic fire scar detection based on remote sensing. This supports the effectiveness of the method for detecting and mapping burnt areas in the Mediterranean region. 相似文献
77.
In this paper, the intra-annual and interannual variability of the sea ice is analysed over the period 1979–2012 from the data and images facilitated by the “National Snow and Ice dates Center”. These data are related to the annual average temperature. The annual average of the marine ice surface area (1979–2012) is very similar in both poles, although its temporary evolution is opposed in both hemispheres. In the Arctic Ocean there is an abrupt reduction of the surface area of the ice during this period. As opposed to it, the marine seas surrounding the Antarctic show an increase of the extension of the ice, especially in the last 15 years, with a maximum value in 2012. With respect to the total of the marine ice over the period 1979–2012, there is an overall deficit balance, because the reduction of the Arctic ice is greater than the increase of the Antarctic ice. 相似文献
78.
M. J. Rodríguez-Peces J. García-Mayordomo J. M. Azañón A. Jabaloy 《Environmental Earth Sciences》2014,72(7):2423-2435
Complete rupture of the Padul Fault represents one of the largest plausible earthquakes in the Sierra Nevada Range, one of the most seismically active regions of Spain. We performed a regional assessment of earthquake-triggered slope instabilities in the western part of the range to determine the most likely types of failures from such an earthquake in the region and suggest where such failures have a higher likelihood of occurring. These results are broadly useful for management of regional life-lines and future development. First, a slope-instability inventory of the Sierra Nevada was produced to identify the most common instability types. Subsequently, the Newmark’s sliding rigid-block methodology, implemented in a geographic information system, was used to obtain the distribution of Newmark displacements in the area considering a M w 6.6 earthquake on the Padul Fault. The Newmark displacements were then compared to the distribution of the inventoried slope instabilities to identify the areas where seismicity could reactivate old slope instabilities or generate new ones, and to identify the involved landslide typology. The most likely seismically induced slope instabilities in the Sierra Nevada are rock falls and rock slides. These types of instabilities could be triggered by Newmark displacements of 2 cm or less. 相似文献
79.
Mineral inclusions in fibrous diamonds: constraints on cratonic mantle refertilization and diamond formation 总被引:1,自引:0,他引:1
We analyzed mineral microinclusions in fibrous diamonds from the Wawa metaconglomerate (Superior craton) and Diavik kimberlites (Slave craton) and compared them with published compositions of large mineral inclusions in non-fibrous diamonds from these localities. The comparison, together with similar datasets available for Ekati and Koffiefontein kimberlites, suggest a general pattern of metasomatic alteration imposed on the ambient mantle by formation of fibrous diamond. Calcium and Fe enrichment of peridotitic garnet and pyroxenes and Fe enrichment of olivine associated with fibrous diamond-forming fluids contributes to refertilization of the cratonic mantle. Saline—carbonatitic—silicic fluid trapped by fibrous diamonds may represent one of the elusive agents of mantle refertilization. Calcium enrichment of peridotitic garnet and pyroxenes is expected in local mantle segments during fibrous diamond production, as Ca in the carbonatitic fluids is deposited into the surrounding mantle when oxidized carbon is reduced to diamond. Harzburgitic garnet evolves towards Ca-rich compositions even when it interacts with Ca-poor saline fluids. An unusual trend of Mg enrichment to Fo95–98 is observed in some olivine inclusions in Wawa fibrous diamonds. The trend may result from the carbonatitic composition of the fluid that promotes crystallization of magnesian olivine and preferentially oxidizes the fayalite component. We propose a generic model of fibrous and non-fibrous diamond formation from carbonatitic fluids that explains enrichment of the mantle in mafic magmaphile and incompatible elements and accounts for locally metasomatized compositions of diamond inclusions. 相似文献
80.
A. Correa‐Metrio S. Lozano‐García S. Xelhuantzi‐López S. Sosa‐Nájera S. E. Metcalfe 《第四纪科学杂志》2012,27(5):509-518
The late glacial and the transition towards the Holocene marked a period of significant environmental change at a global scale. In western Central Mexico, few records span beyond the Holocene, and little is known about Pleistocene climatic and environmental variability. Here we report on the pollen record of a composite sequence made of three cores that cover the last 50 ka (thousands of calibrated radiocarbon years before present) in the Zacapu Basin, western Central Mexico (~1970 m asl). The conjunction of modern pollen rain from the area with the composite fossil pollen sequence from cores Cantabria, Cantabria 1 and CEMCA Point‐1 provided a detailed history of the vegetation of the area. Recognition of modern environmental patterns through individual modern pollen taxa proved difficult, but multivariate analysis separated different vegetation types. No‐modern‐analog communities relative to the modern vegetation cover of the area were evident, especially during periods of drought. Apparently, summer precipitation was significant before 40 ka and after the deglaciation. However, this moisture source declined from ~40 to 10 ka because tradewinds from the Gulf of Mexico were blocked by the eastern mountains of Central Mexico as a result of lower temperatures. By contrast, westerly and northerly winds were enhanced by maximum ice cover from ~19 to 17 ka, providing abundant winter precipitation and therefore preventing extreme drought in the area. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献