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Claudio Campagna Alberto R. Piola Maria Rosa Marin Mirtha Lewis Teresita Fernndez 《Deep Sea Research Part I: Oceanographic Research Papers》2006,53(12):1907-1924
This study describes the association between transient, mesoscale hydrographic features along the axis of the Brazil–Malvinas Confluence, in the SW Atlantic, and the foraging behavior of 2–3-year-old (focal) juvenile southern elephant seals, Mirounga leonina, from Península Valdés, Argentina. Departing from the dominant pattern of foraging on predictable bathymetric fronts on the Patagonian shelf and slope, three females out of 12 satellite-tracked juveniles remained at the edge of young warm-core eddies and near the outer core of cold-core eddies, coinciding with the most productive areas of these temperature fronts. Seal trajectories along high-temperature gradients were always consistent with the speed and direction of surface currents inferred from the temperature distribution and confirmed by surface drifters. Movements of foraging seals were compared with those of surface drifters, coinciding in time and space and yielding independent and consistent data on regional water circulation parameters. The diving pattern recorded for one focal seal yielded shallower dives and a loose diel pattern in the eddy, and a marked diurnal cycle compatible with foraging on vertically migrating prey in the cold waters of the Malvinas Current. Pre-reproductive females that use the mesoscale fronts of the Argentine Basin as an alternative foraging area would benefit from lower competition with more experienced seals and with other top predators that reproduce along the coast of Patagonia. 相似文献
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Teresita Betancur Carlos Palacio Jorge Ignacio Gaviria María Rueda 《Environmental Earth Sciences》2013,70(1):315-328
Interaction between vulnerability and contaminating charge was used in order to determine the groundwater contamination danger. The result of danger being adapted to the scale of impact on human or animal health and ecosystems is known as “risk”. Index and overlapping methodologies such as EPNNA, DRASTIC, SINTACS, GOD AVI, and Ekv were used and compared to evaluate vulnerability. Contaminating charge to the subsoil, which is generated from specific human activity, has four characteristics: kind of contaminant, means of disposal, intensity, and duration. Interaction among these characteristics obtains a Contaminating Charge Index. In the Bajo Cauca Antioqueño region, over 150,000 inhabitants require ground water for meeting their basic needs at home, for cattle breeding activities, and for irrigation. For this region, an assessment of the groundwater contamination of the free aquifer, as well as an estimation of its impact and the danger this contamination may pose to ecosystems or communities has been performed. Analysis of the interaction between vulnerability and threat allows for the creation of danger and risk maps. 相似文献
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Groundwater evolution and mean water age inferred from hydrochemical and isotopic tracers in a tropical confined aquifer 
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下载免费PDF全文 Pedro Villegas Vanesa Paredes Teresita Betancur Jean D. Taupin Luis E. Toro 《水文研究》2018,32(14):2158-2175
The coastal confined aquifer in the Gulf of Urabá (Colombia) is an important water source for the banana agro‐industry as well as for urban and rural communities. However, the main processes controlling recharge and mixing in the aquifer are still poorly understood. Hydrochemical analyses and stable isotope monitoring were conducted to (a) determine groundwater recharge origin, mean groundwater age, and the main processes governing groundwater chemistry and the potential mixing of marine water and the influence of diffusive processes from the two surrounding aquitard layers. Hydrochemical data indicate that the main processes affecting the dissolved chemical composition include cation exchange, dissolution of carbonated and CO2, and silicate weathering. δ18O and δ2H compositions combined with 14C data highlight the differences in climatic conditions between the recharge zone and the confined section of the aquifer, which is close to the Atlantic Ocean. Groundwater samples with 14C ages from recent to 28,300 years BP show a depleted isotopic trend ranging from ?6.43‰ to ?9.14‰ in δ18O and from ?43.2‰ to ?65.7‰ in δ2H. The most depleted δ18O and δ2H compositions suggest a cooler recharge climate than the current conditions (corresponding to the last glacial period of the late Pleistocene). Depleted δ13C values in the total dissolved inorganic carbon indicate the existence of organic material oxidation processes within the geologic formation. These results can be used or transferred to enhance groundwater modelling efforts in other confined coastal aquifers of South America where scarcity of long‐term monitoring data limits water resources planification under a changing climate. 相似文献
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Natural Hazards - The Marsili volcano is the largest known seamount in Europe, located in the Marsili Basin (Aeolian Arc, Tyrrhenian Sea, Italy). The Marsili seamount shows a high probability to... 相似文献
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Piero Bareschino Teresita Gravina Lucio Lirer Antonio Marzocchella Paola Petrosino Piero Salatino 《Journal of Volcanology and Geothermal Research》2007
Fluidization of pyroclastic solids has long been indicated as one key to explain the enhanced mobility of dense pyroclastic gravity currents and their associated hazard. However there is a lack of characterization of the actual pattern and extent of fluidization establishing in real pyroclastic flows and some authors still raise arguments about the relevance of fluidization to the mobility of dense pyroclastic gravity currents. The present paper addresses the fluidization of pyroclastic granular solids with a specific focus on the analysis of factors that may promote homogeneous fluidization and retard solids de-aeration and consolidation. These factors include fines content, particle polydispersity and the establishment of shear flow. 相似文献
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Cerón Wilmar Loaiza Molina-Carpio Jorge Ayes Rivera Irma Andreoli Rita Valeria Kayano Mary Toshie Canchala Teresita 《Natural Hazards》2020,103(1):767-783
Natural Hazards - This article assesses the consistency of the satellite precipitation estimate CHIRPS v.2 to describe the spatiotemporal rainfall variability in the La Plata Basin (LPB), the... 相似文献
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