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  • 1
    Electronic Resource
    Electronic Resource
    Evaluation of an acidification model with data from manipulated catchments in Norway (1990)
    [s.l.] : Nature Publishing Group
    Nature 343 (1990), S. 53-55 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The RAIN project comprises two parallel large-scale manipulations in which acid deposition is experimentally changed at whole catchments4. At Sogndal in western Norway, a 7,200-m2 pristine headwater catchment (SOG2) is artificially acidified by the addition of 70-100 meq m~2 yr"1 H2SO4. At ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/343053a0
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  • 2
    Electronic Resource
    Electronic Resource
    Chemical processes governing soil and water acidification (1987)
    [s.l.] : Nature Publishing Group
    Nature 329 (1987), S. 27-32 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Strong empirical evidence links deposition of strong acids from the atmosphere to acidification of freshwaters and loss offish populations. Chemical processes in soils explain the composition of soil solution and surface waters and when coupled with input-output fluxes these processes, in ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/329027a0
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  • 3
    Electronic Resource
    Electronic Resource
    The “shenandoah national park: Fish in sensitive habitats” (SNP: FISH) project. An integrated assessment of fish community responses to stream acidification (1995)
    Springer
    Water, air & soil pollution 85 (1995), S. 309-314 
    Details
    ISSN: 1573-2932
    Keywords: acidification ; Virginia ; fish response
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The “Shenandoah National Park: Fish in Sensitive Habitats” (SNP:FISH) project is a response to declining pH and acid neutralizing capacity in Shenandoah National Park (SNP) streams. SNP receives more atmospheric sulfate than any other USA national park, and pH had decreased to the point where early negative effects on fish were expected. SNP provides the opportunity to study the early stages of acidification effects on fish. Three different classes of geological formations yield streams with low-ANC (0 μEq/L), intermediate-ANC (60–100 μEq/L) or high-ANC (150–200 μEq/L) waters in SNP. This allows a comparison of responses across a water quality gradient in a small geographic area receiving similar deposition. Both chronic and episodic acidification occur in SNP streams. Biological effects are apparent in fish species richness, population density, condition factor, age, size, and bioassay survival. A primary project objective was to provide the necessary data for development and testing models for forecasting changes in fish communities resulting from changes in stream chemistry. Monitored variables include several which are predictive of acidification effects on SNP fish communities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00476847
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  • 4
    Electronic Resource
    Electronic Resource
    Experimental studies and modelling of enhanced acidification and recovery (1995)
    Springer
    Water, air & soil pollution 85 (1995), S. 77-88 
    Details
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract During the last three decades the experimental manipulations of whole ecosystems have been shown to be a useful and widely used tool for investigation of the effects of air pollution, air pollution reduction strategies and management practices on the health and productivity of forests and the acidification of catchments and fresh waters. Generally the aims have been to investigate the impact of a continued or increased load of air pollutants on the ecosystems, and the possibilities of reversing the acidifying effects by soil amelioration, addition of buffer acting substances or by removal of the air pollutants. Along with the field experiments, models have been developed to predict future effects and dynamics in the ecosystems under different air pollution scenarios. The present paper gives an overview of experimental field manipulation studies and examples of results obtained with the acidification model MAGIC. All the acidification recovery studies performed so far have shown that a reduced input of S to the ecosystem immediately from the first year resulted in reduced output, although the expected parallel reduction in output of Al and H+ did not occur until some years later, or not at all. The MAGIC model generally predicts the results of both acidification and liming field experiments very well, apart from minor discrepancies in year-to-year variability around the observed trends. Several experimental studies have confirmed that reduced input of acidity or increased input of base cations caused no or only slight changes in the pH in the soil. The buffer processes of the soil may cause the effects to be restricted to the very top soil layer, unless the manipulations were very strong. It is concluded that experimental field studies have increased our understanding of the complexity of the ecosystem and highlighted the need for studies integrating field and laboratory work.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00483690
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  • 5
    Electronic Resource
    Electronic Resource
    Influence of organic acids on model projections of lake acidification (1996)
    Springer
    Water, air & soil pollution 91 (1996), S. 271-282 
    Details
    ISSN: 1573-2932
    Keywords: acidification ; diatom ; model ; organic acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract We employed three mathematical models to make quantitative estimates of the pH of 33 statistically-selected lakes in the Adirondack mountains, New York (USA) prior to the Industrial Revolution (1840). The models included 1) the MAGIC watershed acidification model, 2) a paleolimnological model of diatom-inferred pH, and 3) the MAGIC model modified to incorporate an empirically-based model of natural organic acidity. Application of approaches 2) and 3) yielded consistent estimates of pre-industrial Adirondack lakewater pH. However, when the organic acid model was not included, MAGIC calculations and diatom-inferred values showed poor agreement. MAGIC projections of lakewater pH 50 years into the future, under differing atmospheric deposition scenarios, were also sensitive to inclusion of the organic acid model. MAGIC predicted greater recovery in response to reduced deposition when organic acids were not considered. These results suggest that failure to consider the pH buffering of naturally-occurring organic acidity will often result in biased projections which overemphasize the response of lakewater pH to changes in atmospheric inputs of strong acid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00666263
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  • 6
    Electronic Resource
    Electronic Resource
    Testing, improvement, and confirmation of a watershed model of acid-base chemistry (1995)
    Springer
    Water, air & soil pollution 85 (1995), S. 2607-2612 
    Details
    ISSN: 1573-2932
    Keywords: acidification ; model testing ; modeling ; acid deposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Strategies to control the emission of atmospheric pollutants such as sulfur and nitrogen, are generally based in large part on projections using models that simulate the influence of sulfur and/or nitrogen deposition on the acid-base chemistry of surface waters. One of the principal models used throughout Europe and North America for such assessment is the Model of Acidification of Groundwater in Catchments (MAGIC). All watershed models are simplified representations of reality, and as such require careful testing to establish their veracity prior to use for making policy projections. This is particularly true where the use of these model projections has the potential for serious environmental or economic consequences. During the past five years, we have tested the MAGIC model in a large variety of settings and under quite varying environmental conditions. This work has included comparing model hindcast simulations with diatom-inferences of historical acidification, sensitivity analyses to examine the response of the model to alternative assumptions and formulations, and detailed testing of model forecasts by comparing simulated chemistry with the results of catchment-scale and plot-scale experimental acidification and deacidification. Our analyses have elucidated a number of potentially-important deficiencies in model structure and method of application. These have resulted in changes to the model and its calibration procedures. Our work has included in-depth evaluation of issues related to regional aggregation of soils data, background sulfur deposition, natural organic acidity, and aluminum mobilization. The result has been an improved and more thoroughly-tested version of MAGIC. The process we have followed to improve and confirm the MAGIC model has been iterative and time consuming. It required the availability of large volumes of data from experimental manipulation and paleolimnological studies. We believe that such model testing and confirmation efforts should be a critical prerequisite for regional or national assessment activities that are based largely on the results of environmental models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01186227
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  • 7
    Electronic Resource
    Electronic Resource
    Increasing role of nitrogen in the acidification of surface waters in the Adirondack Mountains, New York (1997)
    Springer
    Water, air & soil pollution 95 (1997), S. 313-336 
    Details
    ISSN: 1573-2932
    Keywords: nitrogen ; acidification ; Adirondack Mountains ; atmospheric deposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Assessments of the aquatic effects of acidic deposition have focused on sulfur, as have recent efforts to control the emissions of acidifying compounds. Nitrogen dynamics were excluded from most acidic deposition modeling studies because it was believed that terrestrial ecosystems strongly retain N and because modeling N is a more formidable task than modeling S due to the influence of complex biological processes on N cycling. Re-examination of available data for the Adirondack Mountains of New York suggests that N deposition may be contributing to both chronic and episodic acidification of freshwaters to a greater extent than is generally believed. Previous research concluded that N has played a limited role in acidification processes in these lakes, based on regional averages of chronic chemistry. However, it is now known that historic acidification responses have been spatially variable within the Adirondack Mountains and that the declines in lakewater pH have been less than previously believed. Lakewater NO3 − concentrations are commonly in the range of 5 to 25 μeq L−1 on a chronic basis in portions of the Adirondack region that have experienced significant chronic acidification. These NO3 − concentrations correspond in magnitude to inferred historical acidification. Furthermore, the relative importance of NO3 − as an agent of acidification increases dramatically during snowmelt when conditions are most toxic to fish. The consequence of not addressing N in formulating acidification recovery strategies for the Adirondacks includes the likelihood that we will overestimate the response of surface water to the mandated sulfur emissions reductions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02406172
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  • 8
    Electronic Resource
    Electronic Resource
    INCREASING ROLE OF NITROGEN IN THE ACIDIFICATION OF SURFACE WATERS IN THE ADIRONDACK MOUNTAINS, NEW YORK (1997)
    Springer
    Water, air & soil pollution 95 (1997), S. 313-336 
    Details
    ISSN: 1573-2932
    Keywords: nitrogen ; acidification ; Adirondack Mountains ; atmospheric deposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Assessments of the aquatic effects of acidic deposition have focused on sulfur, as have recent efforts to control the emissions of acidifying compounds. Nitrogen dynamics were excluded from most acidic deposition modeling studies because it was believed that terrestrial ecosystems strongly retain N and because modeling N is a more formidable task than modeling S due to the influence of complex biological processes on N cycling. Re-examination of available data for the Adirondack Mountains of New York suggests that N deposition may be contributing to both chronic and episodic acidification of freshwaters to a greater extent than is generally believed. Previous research concluded that N has played a limited role in acidification processes in these lakes, based on regional averages of chronic chemistry. However, it is now known that historic acidification responses have been spatially variable within the Adirondack Mountains and that the declines in lakewater pH have been less than previously believed. Lakewater NO3 - concentrations are commonly in the range of 5 to 25 μeq L-1 on a chronic basis in portions of the Adirondack region that have experienced significant chronic acidification. These NO3 - concentrations correspond in magnitude to inferred historical acidification. Furthermore, the relative importance of NO3 - as an agent of acidification increases dramatically during snowmelt when conditions are most toxic to fish. The consequence of not addressing N in formulating acidification recovery strategies for the Adirondacks includes the likelihood that we will overestimate the response of surface water to the mandated sulfur emissions reductions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026422031266
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  • 9
    Electronic Resource
    Electronic Resource
    Modeling the Concentration of Aluminum in Surface Waters (1998)
    Springer
    Water, air & soil pollution 105 (1998), S. 643-659 
    Details
    ISSN: 1573-2932
    Keywords: acid deposition ; acidification ; aluminium ; modeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Although the increased mobilization of aluminum from soils to surface waters is widely recognized as one of the most important ecological effects of acidic deposition, lumped-parameter mathematical models of acidification response typically overestimate the change in Al concentration under changing deposition by a considerable margin. The assumption of equilibrium with gibbsite (Al(OH)3) in the MAGIC model and other models of acid-base chemistry is shown to be inconsistent with measured values for a large variety of lake and stream databases. A modified algorithm for predicting Al concentration, based on empirical relationships evident in field data, provided superior estimates of changes in Al concentration in three long-term monitoring data sets and under experimental conditions at two experimental watershed manipulation sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004957426629
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    Paper (German National Licenses)
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  • 10
    Electronic Resource
    Electronic Resource
    Reduced-Form Modelling of Surface Water and Soil Chemistry for the Tracking and Analysis Framework (1998)
    Springer
    Water, air & soil pollution 105 (1998), S. 617-642 
    Details
    ISSN: 1573-2932
    Keywords: acid deposition ; Adirondacks ; integrated assessment ; lake acidification ; mathematical model ; reduced-form modelling ; soil acidification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A reduced-from modelling approach is used to predict soil and lake acidification as part of an integrated assessment of acid deposition effects and control strategies. The reduced-form model is based upon the mechanistic, lumped parameter watershed chemistry model, MAGIC (Model of Acidification of Groundwater in Catchments). Recent improvements to MAGIC are described, and its reduced-form representation in the Tracking and Analysis Framework (TAF), an integrated assessment model for decision and uncertainty analysis, is presented. Reduced-form models are developed for lake acid neutralising capacity (ANC), calcium, pH, and aluminium; and for soil base saturation. The model for lake ANC incorporates long-term depletion of the watershed acid neutralisation fraction, as is predicted to occur with MAGIC. In test calibrations for 33 representative watersheds in the Adirondacks, the resulting reduced-form model provides a close approximation to MAGIC, with average root mean square errors of 0.79 μeq l-1 for ANC, 1.09 μeq l-1 for calcium, 0.16 for pH, 2.52 μeq l-1 for aluminium, and 0.09% for soil base saturation. In addition, improved fish viability models are incorporated in the integrated assessment model, and predictions are demonstrated for a future deposition reduction scenario for the Adirondack region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004993425759
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