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Plasticity in physiological traits in conifers: Implications for response to climate change in the western U.S
2010
Grulke, N.E.
Population variation in ecophysiological traits of four co-occurring montane conifers was measured on a large latitudinal gradient to quantitatively assess their potential for response to environmental change. White fir (Abies concolor) had the highest variability, gross photosynthetic rate (Pg), and foliar carbon (C) and nitrogen (N) content. Despite low water use efficiency (WUE), stomatal conductance (gs) of fir was the most responsive to unfavorable environmental conditions. Pinus lambertiana exhibited the least variability in Pg and WUE, and is likely to be the most vulnerable to environmental changes. Pinus ponderosa had an intermediate level of variability, and high needle growth at its higher elevational limits. Pinus Jeffreyi also had intermediate variability, but high needle growth at its southern latitudinal and lower elevational limits. The attributes used to assess tree vigor were effective in predicting population vulnerability to abiotic (drought) and biotic (herbivore) stresses. Variability in ecophysiological attributes of western U.S. conifers suggests relative capacity of species and populations to respond to environmental change.
Показать больше [+] Меньше [-]Elevated atmospheric deposition and dynamics of mercury in a remote upland forest of southwestern China
2010
Mt. Gongga area in southwest China was impacted by Hg emissions from industrial activities and coal combustion, and annual means of atmospheric TGM and PHg concentrations at a regional background station were 3.98 ng m-3 and 30.7 pg m-3, respectively. This work presents a mass balance study of Hg in an upland forest in this area. Atmospheric deposition was highly elevated in the study area, with the annual mean THg deposition flux of 92.5 μg m-2 yr-1. Total deposition was dominated by dry deposition (71.8%), and wet deposition accounted for the remaining 28.2%. Forest was a large pool of atmospheric Hg, and nearly 76% of the atmospheric input was stored in forest soil. Volatilization and stream outflow were identified as the two major pathways for THg losses from the forest, which yielded mean output fluxes of 14.0 and 8.6 μg m-2 yr-1, respectively.
Показать больше [+] Меньше [-]Increases in Growing Degree Days in the Alpine Desert of the San Luis Valley, Colorado
2010
Mix, Ken | Rast, Walter | Lopes, Vicente L.
Most alpine ecosystem climate change studies identify changes in biota, several report abiotic factors and conditions, few report temperature changes, and few to none discuss growing degree days (GDD) changes. This study provides results of data analysis on changes in number of GDD in the alpine desert of the San Luis Valley (SLV) whose community is dominated by an irrigated agricultural region. Analysis indicates significant increases (p < 0.05) in annual and growing season GDD₁₀, GDD₄.₄ (potato), and GDD₅.₅ (alfalfa) during 1994-2007 compared to 1958-1993. With one exception, all stations experienced significant increases in mean annual daily GDD between 0.12 and 0.50 day⁻² and growing season GDD day⁻² 0.21 and 0.81. Higher temperatures increase numbers of GDD, quickening growth of crops and maturity at the cost of reduced yield and quality. Increases in GDD indicate the Valley's agricultural region and economy may experience negative impacts as yields decrease and water use increases.
Показать больше [+] Меньше [-]Evaluation of Acid Leachable Trace Metals in Soils Around a Five Centuries Old Mining District in Hidalgo, Central Mexico
2010
Jonathan, M. P. | Jayaprakash, M. | Srinivasalu, S. | Roy, P. D. | Thangadurai, N. | Muthuraj, S. | Stephen-Pitchaimani, V.
We present the concentrations and distribution patterns of nine acid leachable trace metals (ALTMs) Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, and Cd in the soil samples from the five century old Pachuca-Mineral de Monte mining district of the Central Mexico. The ALTMs do not show any significant correlation with pH, EC, CaCO₃, and organic carbon. The metal concentration indicates three distinct distribution patterns. Fe, Mn, Cr, Pb, and Zn show enrichment in the high altitude region of the northern and central part of the study area. Likewise, Cu and Cd are enriched in the northern mountainous terrains. Both these groups show strong positive correlation with Mn indicating that they are associated with Mn-bearing minerals. However, we relate the first group of metals to excessive vehicular transportation and second group to mining waste dumps. The third group of ALTMs Co and Ni indicates its direct relationship to ore processing activities. Comparison of ALTMs concentrations from this study and various other studies throughout the world suggests the need to take precautionary measures of surface soil in high altitude areas to avoid metal enrichments and its subsequent environmental problems.
Показать больше [+] Меньше [-]Influence of altitude concerning the contamination of humus soils in the German Alps: a data evaluation approach using PyHasse
2010
Voigt, Kristina | Brüggemann, Rainer | Kirchner, Manfred | Schramm, Karl-Werner
Background, aim and scope In an international project named MONARPOP (Monitoring Network in the Alpine Region for Persistent and other Organic Pollutants), selected chemicals in different environmental media were analysed in the years 2004 and 2005. Seventeen pesticides were chosen and analysed in humus and mineral soil in the German Alps. The samples were taken at different altitudes. Materials and methods In such a rather complex environmental datasets, it is often necessary to compare different sets of criteria and their influence on rankings. In the similarity analysis which is part of the theory of the Hasse diagram technique, we intend to calculate the similarity of different rankings. Furthermore, we perform a so-called dominance-dominance/dominance-separability method, followed by a sensitivity analysis, both subroutines in the newly developed PyHasse programme in order to find out if the concentration of the chemicals can be related to the altitudes at which the samples were taken. Results and discussion It can be demonstrated that the altitude has a considerable influence on the concentration of some organic chemicals in humus: The concentrations of some chemicals increase with the altitude. This increase shows certain irregularities for which several explication attempts including possible effects of atmospheric stratification phenomena in valleys have been made. Conclusion These results should be complemented in further studies with MONARPOP monitoring data from other Alpine countries, e.g. Austria, Switzerland, Italy and Slovenia.
Показать больше [+] Меньше [-]Major and trace elements in soils in the Central Pyrenees: high altitude soils as a cumulative record of background atmospheric contamination over SW Europe
2010
Bacardit, Montserrat | Camarero, Lluís
Background, aim, and scope High mountain soils constitute a long-term cumulative record of atmospherically deposited trace elements from both natural and anthropogenic sources. The main aims of this study were to determine the level of major and trace metals (Al, Ti, Mn, Fe, and Zr) of lithologic origin and airborne contaminating trace elements (Ni, Cu, Zn, As, Cd, and Pb) in soils in the Central Pyrenees as an indication of background contamination over SW Europe, to establish whether there is a spatial pattern of accumulation of trace elements in soils as a function of altitude, and to examine whether altitude-related physicochemical properties of soils affect the accumulation of major metals and trace elements. Methods Major metals and trace elements were measured in “top” (i.e., first 10 cm) and “bottom” (i.e., below 10 cm) soil samples along an altitudinal transect (1,520-2,880 m a.s.l.) in the Central Pyrenees. Total concentrations were determined by X-ray fluorescense spectrometry. Total major metal concentrations were analysed by conventional X-ray fluorescence spectrometry (XRF) with a Siemens SRS 303 instrument. Total trace element concentrations were determined with an energy-dispersive multielement miniprobe XRF analyser. Acid-extractable concentrations were measured by inductively coupled plasma after previous extraction with nitric acid and hydrogen peroxide in closed beakers. Acid-extractable major metal concentrations were measured by inductively coupled plasma (ICP)-Optic Emission Spectrometry with a Perkin Elmer 3200 RL Instrument. Acid-extractable trace element concentrations were determined by ICP-Mass Spectrometry with a Perkin Elmer ELAN 6000. Results Trace element concentration ranges were (in mg kg⁻¹, inventories in g m⁻² between parenthesis) <2-58 (0.5-6.6) for Ni, 6-30 (0.2-3.4) for Cu, 38-236 (1.6-32.4) for Zn, 6-209 (0.2-12.8) for As, 0.02-0.64 (<0.04) for Cd, and 28-94 (0.6-13.0) for Pb. These concentrations were, in general, comparable to those recorded in soils from other European mountainous areas and were in many cases above the threshold recommended for ecosystem protection by regional and European environmental authorities. The highest concentrations were found at lower altitudes, indicating an effect of local contamination up to ∼2,300 m a.s.l. Only above this altitude can trace elements in soils be considered representative of a background, long-range atmospheric contamination. Conclusions None of the storage capacity properties of soils examined were determinant of the differences in elemental concentrations along the altitudinal transect. At the upper altitude range, Ni, Cu, and Pb showed a approximately two- to fivefold increase over the average concentration of the local dominant lithology, reflecting the regional and global background of atmospheric contamination in the area.
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