Last glacial maximum environments in northwestern Patagonia revealed by fossil small mammals

Comparisons of historical and modern assemblages of mammals can yield important insights into patterns and processes of environmental change. Here, we present the first analyses of small mammal assemblages present in northern Patagonia during the last glacial maximum (LGM). Using remains obtained from owl pellets excavated from an archeological cave site (Arroyo Corral I, levels VII–V, carbon dates of 22,400–21,530 cal yr BP), we generate estimates of the minimum number of individuals for all species detected; these estimates, in turn are used to determine relative species abundances. Comparisons of these data with similar analyses of small mammal remains obtained from a second archeological site (ACoII, levels IV–V, carbon dates of 10,010–9220 cal yr BP) as well as from modern owl pellets reveal pronounced changes in relative species abundance since the LGM. In particular, Euneomys chinchilloides and Ctenomys sociabilis – the predominant species during the LGM – declined markedly, suggesting a change from open, bare habitat punctuated by patches of wet meadows and shrubs to the more densely vegetated mosaic of ecotone habitats found in this region today. These data provide important new insights into the environmental changes that have occurred in northern Patagonia over the last 20,000 years.     

Perceptions of environmental change in Moorea,French Polynesia: the importance of temporal,spatial, and scalar contexts

Pacific Islands are considered among the most vulnerable geographies and societies to the effects of climate change and variability (CCV). This study addresses the mismatch between global climate change narratives and local perceptions of environmental change in Moorea, French Polynesia. This study builds on CCV risk perception and adaptation research by analyzing how temporal and historical socio-economic, cultural, political, and ecological contexts shape local perceptions of environmental change among a sample of environmental stakeholders in Moorea. The data were collected prior to the widespread global narrative and social amplification of climate change risk and its particular impact on islands. As such, they offer an important portrait of environmental perceptions in French Polynesia prior to the influence of a circumscribed climate change narrative, which has since come to shape government and NGO responses to environmental change in the Pacific Island Countries and Territories. The data presented in this paper illustrate that perceptions of drivers and effects of environmental change and risk in Moorea are embedded in larger social processes of political economy and ecology, particularly related to contemporary environmental politics, contextualized within the histories of colonialism and tourism-led economic development. Integrating the complexity of local environmental risk perceptions into CCV policy will help to avoid maladaptation, social movements against CCV planning, and may help maximize government and donor investments.     

Lateral variation in structural style of mountain building: controls of rheological and rift inheritance

Many mountain belts exhibit significant along‐strike variation in structural style with changes in the width of the orogen, the geometry and kinematics of the crustal‐scale thrust system, and the degree of partitioning between pro‐ and retro‐wedge deformations. Although the main factors controlling first‐order structural style are understood, the cause of these lateral variations remains to be resolved. Here we focus on the Pyrenees, characterized by significant lateral variation in structural style with a thrust system involving more and thinner thrust sheets in the eastern section than in the western part. Similarly, the prior Mesozoic rifting event was characterized by significant lateral variation in structure. We integrate available geological and geophysical data with forward lithospheric scale numerical models. We show that lateral variation in crustal strength attributed to inherited Variscan crustal composition accentuated during Mesozoic rifting explains the variation in structural style observed during Pyrenean mountain building.     

Methodology to evaluate the renewal period of carbonate aquifers: a key tool for their management in arid and semiarid regions,with the example of Becerrero aquifer,Spain

A methodological procedure is proposed for determining the renewal period (RP), which expresses the ratio of total storage to recharge of carbonate aquifers, and it was applied to the overexploited moderate-size Becerrero carbonate aquifer (southern Spain). To this end, geological and subsurface data—time domain electromagnetic (TEM) soundings and borehole logs—were integrated to construct a three-dimensional (3D) geological model of the aquifer. The interconnected porosity was estimated by analyzing 73 rock samples. The resulting 3D geometrical model makes it possible to quantify the fractions of the aquifer having a confined or unconfined behaviour. Based on the total storage capacity (179?·?10⁶–514?·?10⁶ m³) and available aquifer recharge estimation (4.8?·?10⁶–6.4?·?10⁶ m³/year), an RP between 37 and 106 years is obtained. In view of the RP, an exploitation rate slightly lower than the average recharge of the system is recommended, so that the piezometric level will be stable but below the discharge head that is produced through the springs in natural conditions. The proposed methodology to obtain an aquifer RP and the management strategies designed accordingly are of broad interest, especially for carbonate aquifers, which are abundant in arid and semiarid regions.     

Measurements of volcanic SO2 and CO2 fluxes by combined DOAS,Multi-GAS and FTIR observations: a case study from Turrialba and Telica volcanoes

Over the past few decades, substantial progress has been made to overcome the technical difficulties of continuously measuring volcanic SO₂ emissions. However, measurements of CO₂ emissions still present many difficulties, partly due to the lack of instruments that can directly measure CO₂ emissions and partly due to its strong atmospheric background. In order to overcome these difficulties, a commonly taken approach is to combine differential optical absorption spectroscopy (DOAS) by using NOVAC scan-DOAS instruments for continuous measurements of crateric SO₂ emissions, and electrochemical/NDIR multi-component gas analyser system (multi-GAS) instruments for measuring CO₂/SO₂ ratios of excerpts of the volcanic plume. This study aims to quantify the representativeness of excerpts of CO₂/SO₂ ratios measured by Multi-GAS as a fraction of the whole plume composition, by comparison with simultaneously measured CO₂/SO₂ ratios using cross-crater Fourier transform infrared spectroscopy (FTIR). Two study cases are presented: Telica volcano (Nicaragua), with a homogenous plume, quiescent degassing from a deep source and ambient temperature, and Turrialba volcano (Costa Rica), which has a non-homogeneous plume from three main sources with different compositions and temperatures. Our comparison shows that in our “easier case” (Telica), FTIR and Multi-GAS CO₂/SO₂ ratios agree within a factor about 3 %. In our “complicated case” (Turrialba), Multi-GAS and FTIR yield CO₂/SO₂ ratios differing by approximately 13–25 % at most. These results suggest that a fair estimation of volcanic CO₂ emissions can be provided by the combination of DOAS and Multi-GAS instruments for volcanoes with similar degassing conditions as Telica or Turrialba. Based on the results of this comparison, we report that by the time our measurements were made, Telica and Turrialba were emitting approximately 100 and 1,000 t day^?1 of CO₂, respectively.     

Exposure to ionising radiations arising from the operation of nuclear installations and cancer mortality

World-wide controversy continues to surround the question of whether exposure to ionising radiations arising from nuclear power plants and radioactive fuel cycle facilities could increase the risk of cancer. The objective was to analyse cancer mortality in towns close to Spanish nuclear power plants and radioactive fuel cycle facilities by reference to their history of exposure to artificial radiation generated by such emissions. An ecological cancer mortality study was conducted to know the effect of artificial radiation, estimated taken into account the magnitude of emissions, in towns ≤30 km of any installation. A model of atmospheric and aquatic dispersion of radionuclides was used. As reference, towns within a 50–100 km radius were matched with exposed by socio-demographic characteristics. For analysis purposes, log-linear Poisson models were fitted. The cumulative effective dose was the measure of exposure. Mortality rates ratios were calculated for each tumour site. Natural radiation and socio-demographic matching variables were included in the models, with ‘installation’ as a random effects term. The estimated cumulative artificial radiation dose was below 350 μSv for all sites. For nuclear power plants overall, analysis showed no positive association with increases in the cumulative dose. In the joint analysis of radioactive fuel cycle facilities, however, mortality was observed to rise with increases in the estimated radiation dose in the case of lung, bone and colorectal cancer, and in breast cancer among women. These results would not appear to be due to exposure arising from the operation of the installations, since were not reproduced around installations of the same type.     

Characterization of environmental impact on resources, using strategic assessment of environmental impact and management of natural spaces of “Las Batuecas-Sierra de Francia” and “Quilamas” (Salamanca, Spain)

A new procedure is proposed for joint strategic environmental assessment and environmental impact assessment using simultaneous characterizations in the protected natural area studied to analyse the importance and extent of the impact of human activities within this area on the various natural resources. GIS techniques were used to define territorial models, including environmental information criteria in thematic layers to facilitate environmental diagnosis in the early planning stages in the areas of concern or of higher quality for conservation at different working levels (municipal, district, provincial or national). Traditional conventional environmental impact assessment methods were improved, using spatial analysis to compare scenarios based on the spatial and temporal variability of the impacts identified and their evaluation. This method was applied to the natural space of Las Batuecas-S. de Francia and Quilamas, where in an initial stage the different anthropogenic activities (landfills, etc.) with the potential to cause direct (sewage waters, etc.) or indirect (leachate, etc.) impacts were identified, using checklists and double-entry matrices to analyse actions likely to cause impacts, developing the cartography and identifying environmental impacts potentially damaging to the natural environment. Next, thematic and interpretive mappings were drawn up (surface water quality, aquifer vulnerability to pollution and vulnerability to municipal solid waste) to assess the effects upon resources (water, soil, air, etc.). Finally, by overlapping the impact identification and vulnerability mappings (municipal solid waste, pollution of aquifers and surface water quality) the impact characterization mapping was obtained, showing the absorption capacity of the different sectors to help the responsible bodies set out preventive and/or corrective measures. The essence of this paper is, in methodological terms, its use of two methods simultaneously (strategic environmental assessment and environmental impact assessment) in a protected natural area, allowing it to be extrapolated to any area where territorial management and planning studies need to be carried out.     

Characterisation of rapid infiltration flows and vulnerability in a karst aquifer using a decomposed fluorescence signal of dissolved organic matter

The fluorescent properties of dissolved organic matter (DOM) have been used as natural tracers in various water systems. However, only few studies have focused on groundwater systems, specifically, on karst systems. The aim of this study was to develop the use of the DOM fluorescence signal as a natural tracer, considering the multiple compartments of a karst system. This method was applied to the Lez hydrosystem, which supplies the city of Montpellier with drinking water. The hydrodynamics and hydrochemistry of the spring were monitored beginning March 2006. The DOM fluorescence was measured by the excitation–emission matrix spectroscopy technique. The analysis of the total fluorescence signal confirms the efficiency of this tool to trace rapid infiltration flows. Moreover, the decomposition of the signal into different fluorophores complements the information provided by the total signal. Indeed, the fluorescence emitted by the humic compounds seems to be the ideal tool for identifying rapid infiltration flows. Nevertheless, the fluorescence of protein-like compounds is better correlated with the inflow of faecal bacteria at the outlet. This decomposition of the fluorescence signal is an interesting way to provide information on both the rapid infiltration flow as well as the vulnerability of the karst aquifers.     

Cyclical salt efflorescence weathering: an invisible threat to the recovery of underground mine environment for tourist exploitation

Enhancing the value of an underground mine environment for tourist exploitation involves altering the physico-chemical balance of stone materials whose original mechanical properties guaranteed the structural stability of the site’s galleries and chambers. Humidity and temperature changes caused by the public exhibition of this kind of assets are the main causes of such disorders. After the intervention in the Agrupa-Vicenta mine in La Union (Spain) there were still runoff-water leaks into the mine. These water runoffs through the fault and schistosity planes of the enclosing rock mass give rise to salt precipitation over time. Adapting this mine and turning it into a museum have meant a decrease in relative indoors humidity and an increase in temperature. These variations have caused rocks, which were stable in the original conditions, to increase their rate of physico-chemical weathering due to the polycyclic supergene alteration of the metal sulfides they contain. The resulting release of sulfates into the solution and their subsequent precipitation as single and double salt efflorescence causes haloclasty, deteriorating the rock’s mechanical properties and diminishing the structural stability of the operation. This paper presents the results of characterizing the supergene mineral phases of salt efflorescence in the rock bed enclosing an underground sulfide mine value enhanced for tourist exploitation. Dangers for the structural stability of this type of architectural intervention, associated to the formation of efflorescences, are also identified; these efflorescences are caused by the weathering of rocks that make up its supporting structure.     

Leaching and dilution of fertilizers in the Yucatan karstic aquifer

The application of agrochemicals in crops can cause pollution of aquifers, especially those with a shallow water table and covered by thin soils; such is the case of Yucatan, Mexico. Information about the requirements and application of fertilizers to major irrigation and rainfed crops as well as the volume of water consumed in growing were used to determine the potential amount of nitrate delivered to groundwater. The research reported in this paper was conducted in the metropolitan area of the city of Merida, in Yucatán, Mexico, where groundwater plays an important role since it is the main source of supply, due to the lack of surface water in the region. In addition, the vulnerability of this aquifer is threatened by the various activities taking place in the municipalities, which emphasize agriculture, located within the groundwater basin. This activity is analyzed as a source of contamination given the concentration of NO₃ ^? present in groundwater intended for human consumption. The results show that the contribution of farming that enriches the presence of nitrates in the aquifer is different for each municipality in the study area. For the ZMM, the average nutrient leaching is 44 % of the original mass applied; it could be diluted approximately 12 times, in the groundwater.