Environmental evaluation of elemental cesium and strontium contents and their isotopic activity concentrations in different soils of La Mancha (Central Spain)

Cesium and Strontium concentrations were analyzed in eight pedogenetic soil profiles developed on different rocks from a semiarid mediterranean region: La Mancha (Central Spain). Concentration activities of ¹³⁷Cs and ⁹⁰Sr, as for some soil properties, were also measured. The results are presented in this document: Cs concentrations range between 0.4 and 18.3 mg kg⁻¹ and Sr varies widely between 11.0 and 3,384 mg kg⁻¹. Therefore, it is clear that there is a broad range of concentrations and there are also values significantly higher than the average values stated by several authors. Concentrations of long-life artificial radionuclides (¹³⁷Cs, ⁹⁰Sr) were determined in some of the same soils. The activity concentration mean values (Bq kg⁻¹) were ranging between 0.82 and 21.76 for ¹³⁷Cs and ⁹⁰Sr variations range between 6.73 and 0.35. There were no significant correlations between radionuclides and stable trace elements. The data indicate that the soils do not show significant radioactivity of these elements and therefore they do not pose a danger. By the same token, no risk of contamination by this activity was detected. Finally, spatial patterns seem to be affected by the soil type and some soil properties.     

Digital thermal monitoring of the Amazon forest: an intercomparison of satellite and reanalysis products

Remote sensing and climate digital products have become increasingly available in recent years. Access to these products has favored a variety of Digital Earth studies, such as the analysis of the impact of global warming over different biomes. The study of the Amazon forest response to drought has recently received particular attention from the scientific community due to the occurrence of extreme droughts and anomalous warming over the last decade. This paper focuses on the differences observed between surface thermal anomalies obtained from remote sensing moderate resolution imaging spectroradiometer (MODIS) and climatic (ERA-Interim) monthly products over the Amazon forest. With a few exceptions, results show that the spatial pattern of standardized anomalies is similar for both products. In terms of absolute anomalies, the differences between the two products show a bias near to zero with a standard deviation of around 0.2?K, although the differences can be up to 1?K over particular regions and months. Despite this general agreement, the proper filtering of MODIS daily values in order to construct a new monthly product showed a dramatic reduction in the number of reliable pixels during the rainy season, while for the dry season this reduction is only seen in Northern Amazonia.     

Multiple approaches to formation processes: The Pine Spring Site,southwest Wyoming

Excavations in 1964 at the Pine Spring site in southwest Wyoming concluded that the site contains three cultural occupation levels; the earliest allegedly dates to the terminal Pleistocene and is associated with megafauna. However, excavations in 1998 and 2000, and analysis of the stratigraphy, AMS dates, micromorphology, and artifact carbonate isotopes, along with debitage refitting, density, orientation, inclination, burning, and trample damage, could not replicate the 1964 findings. A hiatus in deposition accounts for the highest density of artifacts, and the three original occupations are palimpsests. There is no unequivocal association between evidence of human activity and megafaunal remains. © 2006 Wiley Periodicals, Inc.     

Inter‐comparison of hydro‐climatic regimes across northern catchments: synchronicity,resistance and resilience

The higher mid‐latitudes of the Northern Hemisphere are particularly sensitive to climate change as small differences in temperature determine frozen ground status, precipitation phase, and the magnitude and timing of snow accumulation and melt. An international inter‐catchment comparison program, North‐Watch, seeks to improve our understanding of the sensitivity of northern catchments to climate change by examining their hydrological and biogeochemical responses. The catchments are located in Sweden (Krycklan), Scotland (Mharcaidh, Girnock and Strontian), the United States (Sleepers River, Hubbard Brook and HJ Andrews) and Canada (Catamaran, Dorset and Wolf Creek). This briefing presents the initial stage of the North‐Watch program, which focuses on how these catchments collect, store and release water and identify ‘types’ of hydro‐climatic catchment response. At most sites, a 10‐year data of daily precipitation, discharge and temperature were compiled and evaporation and storage were calculated. Inter‐annual and seasonal patterns of hydrological processes were assessed via normalized fluxes and standard flow metrics. At the annual‐scale, relations between temperature, precipitation and discharge were compared, highlighting the role of seasonality, wetness and snow/frozen ground. The seasonal pattern and synchronicity of fluxes at the monthly scale provided insight into system memory and the role of storage. We identified types of catchments that rapidly translate precipitation into runoff and others that more readily store water for delayed release. Synchronicity and variance of rainfall–runoff patterns were characterized by the coefficient of variation (cv) of monthly fluxes and correlation coefficients. Principal component analysis (PCA) revealed clustering among like catchments in terms of functioning, largely controlled by two components that (i) reflect temperature and precipitation gradients and the correlation of monthly precipitation and discharge and (ii) the seasonality of precipitation and storage. By advancing the ecological concepts of resistance and resilience for catchment functioning, results provided a conceptual framework for understanding susceptibility to hydrological change across northern catchments. Copyright © 2010 John Wiley & Sons, Ltd.     

The filtering capacity of a tropical riverine wetland: II. Sediment and nutrient balances

The ability of wetlands to improve the quality of water has long been recognized and has led to the proliferation of wetlands as a means to treat diffuse and point source pollutants from a range of land uses. However, much of the existing research has been undertaken in temperate climates with a paucity of information on the effectiveness of wetlands, particularly natural wetlands, in tropical regions. This paper contributes to addressing this issue by presenting a comprehensive measurement based assessment of the potential for a naturally occurring tropical riverine wetland to improve the quality of the water entering it. We found small net imports and exports of sediment to/from the wetland in individual years, but over the longer term this kind of wetland is neither a sink nor source of sediment. In contrast, phosphorus was continually removed by the wetland with an overall net reduction of 14%. However, it should be noted that there is no ‘permanent’ gaseous loss mechanism for phosphorus, and its removal from the water column is equal to its accumulation in the wetland soil. We found very little removal of nitrogen by this type of wetland from several analyses including: (i) Surface and groundwater fluxes, (ii) Estimation of water column and soil denitrification rates, (iii) Wetland residence times, and (iv) Hydraulic loading. We also found no clear evidence for transformation of nitrogen to more or less bio‐available forms. Hence, while the benefits of using wetlands to improve water quality in controlled environments have been demonstrated in the literature, these benefits may not always be directly translated to unmanaged natural wetland systems when there is strong seasonality in flows and short residence time during the periods of maximum sediment and nutrient load. Copyright © 2011 John Wiley & Sons, Ltd.