No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
A method for upscaling soil parameters for use in a dynamic modelling assessment of water quality in the Pyrenees
Abstract
Dynamic modelling of hydrochemistry is a valuable tool to study and predict the recovery of surface waters from acidification, and to assess the effects of confounding factors (such as delayed soil response and changing climate) that cause hysteresis during reversal from acidification. The availability of soil data is often a limitation for the regional application of dynamic models. Here we present a method to upscale site-specific soil properties to a regional scale in order to circumvent that problem. The method proposed for upscaling relied on multiple regression models between soil properties and a suite of environmental variables used as predictors. Soil measurements were made during a field survey in 13 catchments in the Pyrenees (NW Spain). The environmental variables were derived from mapped or remotely sensed topographic, lithological, land-cover, and climatic information. Regression models were then used to model soil parameters, which were supplied as input for the biogeochemical model MAGIC (Model for Acidification of Groundwater In Catchments) in order to reconstruct the history of acidification in Pyrenean lakes and forecast the recovery under a scenario of reduced acid deposition. The resulting simulations were then compared with model runs using field measurements as input parameters. These comparisons showed that regional averages for the key water and soil chemistry variables were suitably reproduced when using the modelled parameters. Simulations of water chemistry at the catchment scale also showed good results, whereas simulated soil parameters reflected uncertainty in the initial modelled estimates.
... Thus, the projections that foresee a progressive acidification recovery of the surface waters due to the decrease in industrial activity, which peaked during the 1960s to 1980s in this region (e.g. Camarero et al., 2009b), are not applicable in the high-elevation NVC. ...
A historical series of aerial photographs spanning more than 70 years (1945-2018) revealed that natural acid rock drainage (ARD) has experienced an intensification in the Noguera de Vallferrera alpine catchment (Central Pyrenees) due to climate change during the last decade. ARD manifests by the precipitation of whitish aluminum-compounds that strikingly cover the beds of some gullies and streams in high-mountain catchments. The total length of affected streams has increased from ca. 5 km (1945) to more than 35 km (2018). Up to 68 water samples were collected in three main areas to determine the spatial variation in acidity and concentration of dissolved metals, representative of surface and subsurface waters. Concentration of aluminum clearly correlates with acidity of waters. Aluminum precipitation occurs where acidic waters, enriched in metals due ARD related to the oxidation of sulfides, mix with non-acidic waters. In addition to aluminum, other potentially toxic trace metals are present at concentrations well above the quality standards for natural waters. Here, we show that climate warming and the severe droughts recorded in the last decade are the most plausible causes for the observed ARD intensification. This result is supported by a good correlation between the regional ascending rate of the periglacial limits (ca. 46 m-height/decade) and the rising rate of the maximum elevations at which ARD occurs (ca. 45 to 55 m-height/decade). In addition to climatic control, we also show that the local geomorphology is playing a major role. The distribution of periglacial deposits (rock glaciers, protalus ramparts, cones and talus slopes) and deep-seated gravitational slope deformations exert a strong control on the spatial patterns and hydrodynamics of ARD. A better understanding of the phenomenon and the monitoring of its evolution can provide clues on these side effects of climate warming, here and in many other alpine catchments worldwide.
... Thus, each soil pit was dug until bedrock was reached, and at least three soil samples were collected in each pit from different soil layers. Other topographic variables, such as soil depth, altitude, slope, and local human activities, were also recorded (Camarero et al. 2009). The samples for the different soil layers were packed in laboratory soil pans and sieved in the field to retrieve stones, which were weighed using a dynamometer and discarded. ...
s
Soil databases are one of the most important inputs for watershed models, and the quality of soil properties affects how well a model performs. The objectives of this study were to (1) quantify the sensitivity of model outputs to soil properties and to (2) use site-specific soil properties as a substitution for more accurate hydrological and nonpoint source (H/NPS) predictions. Soil samples were collected from a typical mountainous watershed in China, and the impacts of soil sample parameters on H/NPS predictions were quantified using the Soil and Water Assessment Tool (SWAT). The most sensitive parameters related to predicting flow, sediment, and total phosphorus (TP) mainly were the soil hydrological, the channel erosion processes, and the initial soil chemical environment, respectively. When the site-specific soil properties were used, the uncertainties (coefficient of variation) related to predicting the hydrology, sediment and TP decreased by 75∼80 %, 75∼84 %, and 46∼61 %, respectively. Based on changes in the Nash-Sutcliff coefficient, the model performance improved by 4.9 and 19.45 % for the hydrological and sediment model, accordingly. However, site-specific soil properties did not contribute to better TP predictions because of the high spatial variability of the soil P concentrations across the large watershed. Thus, although site-specific soil samples can be used to obtain more accurate H/NPS predictions, more sampling sites are required to apply this method in large watersheds.
... It is known that scale effects pervade the hydrological sciences have been widely accepted. Although a number of methods have been presented to upscale site-specific parameters' properties to a regional scale (Lluís et al., 2009), it is still unclear whether these approaches would be suitable for some geochemical systems. A certain sensitivity analyses of the parameters related to the groundwater model has offered a rough estimate of the significant of input parameters in evaluating the target element concentrations (EPA, 1998). ...
... Remotely sensed vegetation parameters can be used as surrogates for ecological productivity (Curran et al., 1992;Scanlon et al., 2002) and these data have been successfully used to predict below ground C stocks (Burnham and Sletten, 2010;Paruelo et al., 2010). Many of these relationships have been exploited to predictively map the distribution of soil C using both statistical and geostatistical approaches (Arrouays et al., 1998;Camarero et al., 2009;Delbari et al., 2010;Vasques et al., 2010). ...
We investigated soil carbon (C) and nitrogen (N) distribution and developed a model, using readily available geospatial data, to predict that distribution across a mountainous, semi-arid, watershed in southwestern Idaho (USA). Soil core samples were collected and analyzed from 133 locations at 6 depths (n=798), revealing that aspect dramatically influences the distribution of C and N, with north-facing slopes exhibiting up to 5 times more C and N than adjacent south-facing aspects. These differences are superimposed upon an elevation (precipitation) gradient, with soil C and N contents increasing by nearly a factor of 10 from the bottom (1100m elevation) to the top (1900m elevation) of the watershed. Among the variables evaluated, vegetation cover, as represented by a Normalized Difference Vegetation Index (NDVI), is the strongest, positively correlated, predictor of C; potential insolation (incoming solar radiation) is a strong, negatively correlated, secondary predictor. Approximately 62% (as R2) of the variance in the C data is explained using NDVI and potential insolation, compared with an R2 of 0.54 for a model using NDVI alone. Soil N is similarly correlated to NDVI and insolation. We hypothesize that the correlations between soil C and N and slope, aspect and elevation reflect, in part, the inhibiting influence of insolation on semi-arid ecosystem productivity via water limitation. Based on these identified relationships, two modeling techniques (multiple linear regression and cokriging) were applied to predict the spatial distribution of soil C and N across the watershed. Both methods produce similar distributions, successfully capturing observed trends with aspect and elevation. This easily applied approach may be applicable to other semi-arid systems at larger scales.
... Upscaling takes a model that is applicable at a sitespecific scale (at which observations are made), and projects the outcome in a way that it is applicable at coarser scale (regional or global) [4]. One of the main problems encountered in upscaling occurs when singlesite observations do not represent spatial heterogeneity of the parameters or variables at larger spatial scales. ...
The Multi-scale Soil Information System (MEUSIS) can be a suitable framework for building a nested system of soil data that
could facilitate interoperability through a common coordinate reference system, a unique grid coding database, a set of detailed
and standardized metadata, and an open exchangeable format. In the context of INSPIRE Directive, MEUSIS may be implemented
as a system facilitating the update of existing soil information and accelerating the harmonization of various soil information
systems. In environmental data like the soil one, it is common to generalize accurate data obtained at the field to coarser
scales using either the pedotransfer rules or knowledge of experts or even some statistical solutions which combine single
values of spatially distributed data. The most common statistical process for generalization is averaging the values within
the study area. In this paper, we do not present a simple averaging of numerical values without any further processed information.
The upscaling process is accompanied with significant statistical analysis in order to demonstrate the method suitability.
The coarser resolution nested grids cells (10× 10km) represent broad regions where the calculated soil property (e.g., organic
carbon) can be accurately upscaled. Multi-scaled approaches are urgently required to integrate different disciplines (such
as Statistics) and provide a meta-model platform to improve current mechanistic modeling frameworks, request new collected
data, and identify critical research questions. Past papers have described in detail the upscaling methodology while our present
approach is to demonstrate an important application of this methodology accompanied with statistical evidence.
KeywordsMulti-scale soil information system–MEUSIS–Upscaling–Soil data–Descriptive statistics–INSPIRE
... Soils from the Pyrenees were sampled in 21 catchments in subalpine and alpine areas. Th e catchments were distributed along the whole mountain range covering a wide range of elevation (1845–2900 masl), slopes, and aspects, and therefore including diff erent climatic conditions, vegetation coverage, and lithologies (Camarero et al., 2009a). Granites and slates are the most common bedrocks in the Pyrenees, but limestone also occurs in the central and western areas. ...
We evaluated the chemical properties controlling phosphate (PO(4)-P) sorption characteristics of alpine soils at elevations of 1725 to 2900 m above sea level in four European mountain ranges (the Tatra Mountains, Slovakia and Poland; the Alps, Austria; the Pyrenees, Spain and France; and the Rila Mountains, Bulgaria). PO(4)-P sorption isotherms were determined, ranging in concentration from 0 to 6.5 mM KH(2)PO(4) at original soil pH, and were evaluated using the Langmuir equation. PO(4)-P sorption maxima (X(max)) varied from 6 to 145 mmol kg(-1) in the dry (105 degrees C) fine soil fraction (<2 mm). Concentrations of Al oxohydroxides, determined as oxalate extractable aluminum (Al(o)), ranged between 36 and 770 mmol kg(-1), and were the dominant parameter affecting the soil's ability to adsorb PO(4)-P. In the Tatra Mountains, Rila, and Alps, oxalate-extractable iron (Fe(o)) was also important, while in the Pyrenees we found a significant correlation (p < 0.01) between X(max) and total organic C concentrations. The ability of Al and Fe oxohydroxides to adsorb PO(4)-P was higher in areas with more acidic soils (the Tatra Mountains) than in areas with higher soil pH (the Pyrenees), and in the more acidic uppermost organic soil horizons than in mineral soil horizons. A simple model based only on two basic soil characteristics (Al(o) and pH) explained 81 to 89% of the X(max) variability observed in individual mountain areas and 74% of the X(max) variability associated with all samples.
... It is widely accepted that scale effects pervade the hydrological sciences (Barry et al., 2002). Although some methods (Lluís et al., 2009) have been presented to upscale site-specific parameters' properties to a regional scale, it is still unclear whether these approaches would be suitable for complex geochemical systems with the nonlinear process. ...
In 2005 a pollution accident occurred in the Songhua River, which is geographically located next to groundwater supply plants. This caused public concern about the transport and fate of nitrobenzene (NB) in the groundwater. This paper discusses the mechanisms and effects of the transport and fate of NB in groundwater based on pilot scale experiments conducted in the laboratory, including a simulation experiment, bench-scale batch tests and a one-dimensional numerical model. Parallel batch tests showed that the adsorption of NB to the clay and sand followed the Langmuir-type isotherm, and clay had a greater NB adsorption capacity than sand. NB biodegradation in different conditions was well fitted by the Monod equation and the q(max) values varied from 0.018 to 0.046 h(-1). Results indicated that NB's biodegradation was not affected by the initial NB concentration. Numerical modeling results indicated a good match between computed and observed data, and in the prediction model NB entered the groundwater after the pollution accident. However, the highest concentration of NB was much lower than the allowable limit set by the national standard (0.017 mg/L).
Sulfur (S) and nitrogen (N) increasing anthropogenic emissions in the last century has arisen wide concern on the ecological effects of S and N deposition. In this paper, we use bulk deposition and stream water measurements in the central Pyrenees (PYR-C and PYR-AT sites) and Montseny (MSY-TM0) covering different time lengths in the period 1983-2017 to investigate how these mountain environments respond to ongoing changes of regional emissions to the atmosphere. PYR-C, in spite of its position far away from urban and industrial areas, presented higher SO4-S, NO3-N and NH4-N bulk deposition than the Montseny site closer to Barcelona and the inclusion of dry deposition only reversed this pattern for NO3-N. This indicates that distance to pollution sources does not protect these mountain sites from a considerable impact of pollution. Time-trends in SO42- and NO3- concentrations in bulk deposition were similar between sites: SO42- monotonically decreased, while NO3- increased until the mid-2000 s and decreased thereafter. In the period 1983 to 2017, SO2 emissions in Europe (EU-28) decreased by 95%, while in the SO42- concentrations in bulk deposition declined by 35-50% in Pyrenees and Montseny respectively and SO42- concentrations in the streams by 25-35%, respectively. Other sources of SO42- (e.g. episodic African dust) may explain the different reduction rate between anthropogenic emissions and bulk deposition. Net S budget was positive for MSY-TM0 (indicating flushing from the catchment) and negative for the PYR-C site (indicating retention), while it was close to zero for the other Pyrenean site, but in the PYR-C site net retention showed a significant increasing trend tending to lower retention in recent years. Bulk N deposition in the Pyrenees was lower but stream concentrations and export was higher than at Montseny, this leading to less N retention in the Pyrenean sites. However, the MSY-TM0 site showed a trend towards less N retention in recent years. This was driven by higher exports during the wet months, which would correspond to a first stage of N saturation according Stoddard's classification.
The MAGIC model of the responses of catchments to acidic deposition has been applied and tested extensively over a 15 year period at many sites and in many regions around the world. Overall, the model has proven to be robust, reliable and useful in a variety of scientific and managerial activities. Over the years, several refinements and additions to MAGIC have been proposed and/or implemented for particular applications. These adjustments to the model structure have all been included in a new version of the model (MAGIC7). The log aluminium - pH relationship now does not have to be fixed to aluminium trihydroxide solubility. Buffering by organic acids using a triprotic analog is now included. Dynamics of nitrogen retention and loss in catchments can now be linked to soil nitrogen and carbon pools. Simulation of short-term episodic response by mixing fractions of different water types is also possible. This paper presents a review of the conceptual structure of MAGIC7 relating to long-term simulation of acidification and recovery, describes the conceptual basis of the new nitrogen dynamics and provides a comprehensive update of the equations, variables, parameters and inputs for the model.
This study investigates the usefulness of satellite images for the study of mountain lake ecosystems and develops an effective approach to extract landscape features of interest for the determination of the lake characteristics. A methodology is proposed taking advantage of the unique spectral features of the land cover classes defined for this study along to their statistical information to determine different band pairs which contain key information for every class. The land cover classes are extracted separately from the selected pair of bands and the class images obtained are later added together in a final classified image. This methodology is applied to ten european sites representing glacial lake districts. The GIS ArcInfo is used to integrate the information obtained from the satellite images with the lake catchments thus the final classified images are merged with the lake catchment boundary vectors of the study areas therefore every pixel is assigned to the corresponding lake catchment. Moreover different patterns were observed in the spatial distribution of the land cover classes. These patterns were analyzed and classified as different lithological classes and every lake catchment was assigned to the corresponding lithological class. At the end every studied pixel has two attributes: land cover and lithology which together give a more detailed perception of the terrain.
The assessment of the effects of atmospheric inputs on the chemistry of mountain lakes requires realistic data on the chemical composition of these inputs. However, precipitation sampling stations are usually at lower altitudes than lakes. The location of the stations may lead to a mistaken appraisal of precipitation chemistry, since orography strongly influences the formation of storms caused by air masses coming from different directions, and altitude affects the mechanisms of transport and deposition of solutes in several ways. The effect of altitude on the chemistry of precipitation in the Pyrenees was studied at three sampling points located at different heights (1600, 1900, and 2200 m above sea level) within the same valley, orientated in a NE-SW direction, Sampling was carried out over a period (summer-autumn 1990) long enough to ensure a statistically representative collection of events with a different origin, Three main results were derived from this study. (1) The main source of variability was the cation-anion balance, which was determined by the origin of the wet air masses: rains from the Atlantic were more acidic than those coming from the Mediterranean. (2) There was no significant difference in the chemistry of bulk precipitation with altitude within the range 1600-2200 m asl, in which most of the lakes in the Pyrenees are found. (3) Below-cloud mechanisms of deposition had a significant influence on NO3- concentration. The concentration of most of the solutes was independent of precipitation volume, except for NO3-.
The process-oriented catchment-scale model MAGIC was used to simulate water chemistry at Lake Redó, a high mountain lake in the Central Pyrenees, Spain. Data on lakewater and atmospheric deposition chemistry for the period 1984-1998 were used to calibrate the model, which was then used to reconstruct past and to provide forecasts for three hypothetical future scenarios of deposition. Forecast scenarios considered several combinations of changes in S and N deposition due to abatement strategies, and in base cation deposition due to climate-induced changes in air-mass trajectories from northern Africa. Scenario 1 assumed constant deposition of base cations at the present level plus the expected decrease in S and N deposition resulting from reduced emissions; scenario 2 (best case) assumed an increase in base cation deposition plus the same decrease in S and N deposition as in scenario 1; scenario 3 (worst case) assumed a decrease in base cation deposition plus no decrease in S and N deposition. The hindcast indicated that during the past 140-year period changes in lake water chemistry have been significant for a remote mountain catchment, although no substantial acidification has occurred In this regard Lake Redó can be described as a "non-sensitive lake" maintaining a reference condition. The forecasts indicated changes that do not affect this status, but the trends, even if slight, were different between scenarios. A slight decline in the surface water ANC is predicted by Scenario 3. The N budget indicates an unusually low retention in the catchment, which may result in enhanced sensitivity to further increased N deposition. Some of the discrepancy between modelled and measured Ca2+ in lake water during 1984-98 could be explained by changes in rainfall amounts and by increased weathering rates due to increases in air temperature.
Rates of acidic deposition from the atmosphere (`acid rain') have decreased throughout the 1980s and 1990s across large portions of North America and Europe. Many recent studies have attributed observed reversals in surface-water acidification at national and regional scales to the declining deposition. To test whether emissions regulations have led to widespread recovery in surface-water chemistry, we analysed regional trends between 1980 and 1995 in indicators of acidification (sulphate, nitrate and base-cation concentrations, and measured (Gran) alkalinity) for 205 lakes and streams in eight regions of North America and Europe. Dramatic differences in trend direction and strength for the two decades are apparent. In concordance with general temporal trends in acidic deposition, lake and stream sulphate concentrations decreased in all regions with the exception of Great Britain; all but one of these regions exhibited stronger downward trends in the 1990s than in the 1980s. In contrast, regional declines in lake and stream nitrate concentrations were rare and, when detected, were very small. Recovery in alkalinity, expected wherever strong regional declines in sulphate concentrations have occurred, was observed in all regions of Europe, especially in the 1990s, but in only one region (of five) in North America. We attribute the lack of recovery in three regions (south/central Ontario, the Adirondack/Catskill mountains and midwestern North America) to strong regional declines in base-cation concentrations that exceed the decreases in sulphate concentrations.
We present a review of the main trends of vegetation zonation in the entire Pyrenean mountain system, including previous overviews and a great many papers on flora and vegetation. The main floristic territories are roughly set as parallel zones along the main axis. The high mountain zone forms a central core, characterized by the domi-nant Boreo-Alpine element. The Atlantic mid altitudes and lowlands (mainly on the north face of the chain) and the mid altitudes of the Iberian side bear Medioeuropean flora as their dominant element, but include a good representation of the transitional Submediter-ranean element. Lower down, the Iberian lowlands harbour dominant Mediterranean flora. This landscape zonation may be understood in terms of the Alpine model, by which high mountains include three belts (subnival, alpine, subalpine), the mid altitudes show one belt on the Atlantic face (montane) and two on the Iberian face (montane, submon-tane), and the low altitudes form a basal belt with two contrasting faces (Atlantic and Mediterranean). The vegetation belts are briefly defined in terms of the main potential communities, since these are the most closely related to bioclimate. Thus, the boundaries between belts mostly coincide with boundaries of potential domains, but a few vegetation domains occur in two neighbouring belts. Then, substrata properties and regional climatic variation within the same belt produce noticeable shifts in the potential domains. This makes the basal and montane belts more diverse throughout the Pyrenean range than the high moun-tain belts. The boundaries between belts run a bit higher on south-facing slopes than on north-facing slopes, reflecting the effect played by topographic thermal and hydric drivers on vegetation. Also, the somewhat higher location of the boundaries in the central sector than towards the edges of the chain is connected with the continental character of the inner Pyrenean area.
This paper reviews the problems of upscaling that arise, in the context of global change research, in a wide variety of disciplines in the physical and social sciences. Upscaling is taken to mean the process of extrapolating from the site-specific scale at which observations are usually made or at which theoretical relationships apply, to the smallest scale that is resolved in global-scale models. Upscaling is pervasive in global change research; although in some cases it is done implicitly. A number of conceptually distinct, fundamental causes of upscaling problems are identified and are used to classify the upscaling problems that have been encountered in different disciplines. A variety of solutions to the upscaling problems have been developed in different disciplines, and these are compared here. Improper upscaling can dramatically after model simulation results in some cases. A consideration of scaling problems across diverse disciplines reveals a number of interesting conceptual similarities among disciplines whose practitioners might otherwise not communicate with each other. Upscaling raises a number of important questions concerning predictability and reliability in global change research, which are discussed here. There is a clear need for more research into the circumstances in which simple upscaling is not appropriate, and to develop or refine techniques for upscaling.
Extremely high emissions of S and N compounds in Central Europe (both 280 mmol m-2 yr-1) declined by 70and 35%, respectively, during the last decade. Decreaseddeposition rates of SO4
-2, NO3
-, and NH4
+ in the region paralleled emission declines. The reduction in atmospheric inputs of S and N to mountain ecosystemshas resulted in a pronounced reversal of acidification in the Tatra Mountains and Bohemian Forest lakes. Between the 1987–1990and 1997–1999 periods, concentrations of SO4
-2 and NO3
- decreased (average standard deviation) by 227 and 127 mol L-1, respectively, in theTatra Mountains, and by 197 and 1510 mol L-1, respectively, in the Bohemian Forest. Their decrease was compensated in part (1) by a decrease in Ca2+ + Mg2+ (177 mol L-1) and H+ (46 mol L-1), and an increase in HCO3
-(1010 mol L-1) in the Tatra Mountains lakes, and (2) by a decrease in Al (74 mol L-1), Ca2+ + Mg2+ (96 mol L-1), and H+ (65 mol L-1), in Bohemian Forest lakes. Despite the rapid decline in lake water concentrations of SO4
-2 and NO3
- in response to reduced S and N emissions, their present concentrations in some lakes are higher than predictionsbased on observed concentrations at comparable emission rates during development of acidification. This hysteresis in chemical reversal from acidification has delayed biological recovery of the lakes. The only unequivocal sign of biological recovery hasbeen observed in ern Lake (Bohemian Forest) where a cladoceran species Ceriodaphnia quadrangular has recentlyreached its pre-acidification abundance.
Pristine and sensitive environments, such as remote alpine and arctic lakes, are particularly susceptible to the effects of climate change. However, these remote environments do not have sufficiently long instrumental climate records to support studies on contemporary climate change. The issue of the scarcity of instrumental climate data at remote regions is addressed by reconstructing monthly mean air temperatures from 1781 to 1997 AD at eleven remote alpine and arctic lakes in Europe, as part of the MOuntain LAke Research (MOLAR) project. Stepwise multiple regression is applied to establish linear transfer functions of temperatures between each of eleven upland records and twenty homogenised long lowland records. Twelve monthly transfer functions are obtained for each lake. The skill of these transfer functions is found to range typically between 60 and 99%. The lower skill values generally correspond to winter months. The temperature reconstructions obtained using the transfer functions need to be corrected with vertical temperature gradients. Air-temperature lapse rates were obtained for each lake region by spatial interpolation of radiosonde air-temperature data (1990–1997). The resulting reconstructions at each lake were checked using air-temperature data (1996–1997) from automatic weather stations installed at the lakes during the MOLAR project. We estimate the typical reconstruction errors to be about 1.3 C for low-sun months and about 0.98 C for high-sun months. Trend analyses on the reconstructed annual mean air temperatures at the lakes show two distinct types of trends for the 19th and 20th centuries. During the period 1801–1900, the western European lakes show no significant trend whereas annual mean air temperatures at the eastern European lakes decrease significantly. The period 1901–1997 presents a warming trend at all but the Fennoscandian lakes. Our results are in good agreement with previous studies on the spatial distribution and magnitude of temperature change in Europe. Principal component analysis performed on the reconstructed annual mean air temperature reveals two different regimes of trends for the past two centuries. It also allows a regional clustering of the inter-annual variability of air temperature at the lakes to be identified.
The prediction of soil C stocks across the landscape has been increasingly studied in many areas of the world. Soil organic
C storage in mountain areas is highly heterogeneous, mainly as a result of local-scale variability in the soil environment
(topography, stoniness, parent material) and microclimate. The aims of the present study are to estimate soil organic C stocks
(SOCS) in mineral soils of high-altitude grasslands of the Pyrenees and determine whether climatic and topographic variables
can be used as predictors of SOCS and organic C content in the surface soil horizons of these ecosystems. For that purpose
we sampled 35 soil profiles in subalpine and alpine grasslands including a range of altitudes, slopes and aspects. We analysed
the soils for stoniness, bulk density, total C, texture, and C-to-N ratio and determined topographical variables. We used
georeferenced climatic information for climatic descriptions of the sites. SOCS were highly correlated with soil depth. However,
we were not able to predict soil depth by using environmental and topographic variables. In spite of this fact, altitude and
aspect explained 41.2% of the SOCS variability while summer temperature and precipitation combined with aspect explained 56.9%
of the variability of the organic C content of the surface layer (OC). The SOCS were low at high altitudes, probably as a
result of an overall temperature limitation of net primary productivity. Under these conditions, the effect of aspect was
small. The highest SOCS occurred at the lowest altitudes for ENE or WNW aspects, showing sharper decreases towards the south
than to the north. The harsh climatic conditions and low-plant productivity that occur at the northern slopes reduced SOCS
at the highest altitudes. In contrast, southern aspects showed similar organic C content along the altitudinal gradient. The
OC variability in the surface soils not explained by climatic or topographic variables was partially related to the characteristics
of soil organic matter, which may depend on the plant communities.
A comparison was made between soils on north- and south-facing slopes of six cinder cones in the Springerville volcanic field (SVF), Arizona, in order to determine the influence of slope aspect on soil weathering processes. Twenty-four soil pedons were sampled on different aspects of six cinder cones. To control for the influence of slope on pedogenesis, all sample sites possessed slopes of 17±2°. Soil weathering processes were characterized by solum depth, texture, and Ca:Zr chemical weathering indices. Quartz and mica were used to identify eolian additions to the volcanic soils. Accelerated rates of weathering and soil development were found to occur in soils on south-facing slopes while no trend with aspect was found for eolian additions. Accelerated rates of weathering and soil development may influence cinder cone degradation and cone morphology.
The central grassland region of the United States (US) encompasses major gradients in temperature and precipitation that determine the distribution of plant life forms, which in turn may influence key ecosystem processes such as nutrient cycling and soil organic matter dynamics. One such gradient is the threefold increase in precipitation from the eastern Colorado shortgrass-steppe, in the rainshadow of the Rocky Mountains, to the tallgrass prairie in eastern Kansas. We investigated the relative roles of plant species and plant cover in influencing soil C and N cycling in three sites along this gradient. Plant cover (i.e. the presence or absence of an individual plant) was relatively more important than plant species in explaining variability in soil properties at the dry site, the Central Plains Experimental Range in north eastern Colorado. However, plant species explained relatively more of the variability in soil properties than did plant cover at the two wetter sites, Hays and Konza, in central and eastern Kansas. The wetter sites had more continuous plant cover, resulting in less plant-cover-induced variation in soil C and N, than did the dry site, which had distinct patches of bare ground. Plant species at the wetter sites had higher and more variable levels of tissue C : N than plant species at the dry site, due to both within species changes and changes in species composition. Aboveground tissue C : N was better correlated with net N mineralisation rates at the wet sites than the dry site. Thus tissue chemistry appears to exert more control on nitrogen dynamics at the wet than the dry sites. The results suggest that plant species traits that are relevant to nutrient cycling (e.g. tissue C : N ratios, spatial patterns, productivity) reflect environmental limitations as well as species physiological potentials. Furthermore, a dominant environmental driver such as precipitation may ameliorate or exaggerate the importance of individual species traits for nutrient cycling.
The results from an application of MAGIC (Model of Acidification of Groundwater In Catchments) to 733 Scottish catchments are presented. The availability of representative, good quality soil data is frequently limiting factor for biogeochemical modelling, particularly those involving modelling at various spatial scales. This study tests the sensitivity of MAGIC to soil input data derived from two different methodologies; the "nearest neighbour method" considers the closest representative soil profile to a catchment, and the "spatial weighting method" of all soil types identified in a catchment, based on a soil physico-chemical classification of Scotland. Soil data (soil depth, density, cation exchange capacity and base saturation) calculated using the "nearest neighbour method" and the "spatial weighting method" were highly variable, although the range of upper and lower limits were greater for soil data produced using the nearest neighbour method. In contrast to the predominantly organic soil data calculated by the nearest neighbour method, the spatially weighted soil parameters included a greater proportion of mineral soils. With regard to simulated surface water Acid Neutralising Capacity (ANC) for 1851, 1997 and 2050, MAGIC predictions were similar irrespective of the methodology used to determine soil input parameters. However, soil input data derived from both methods resulted in variable base saturation predictions. It is concluded that the "nearest neighbour" methodology is most appropriate if the objective is to determine the predicted response of the most acid- sensitive sites within a region in line with the approach used in Critical Laod mapping. On the other hand, "spatial weighting" integrates catchment soils and represents a more robust methodology by which to determine changes in median soil and water response in a regional context. The anticipated reductions in S emissions associated with the Second S Protocol are predicted to have a marginal beneficial effect on the recovery of soils and surface waters of Scotland.
Following the decline in sulphur deposition in Europe, sulphate dynamics of catchments and the reversibility of anthropogenic acidification of soils and freshwaters became of major interest. Long-term trends in sulphate concentrations and fluxes in precipitation/throughfall and freshwater of 20 European catchments were analysed to evaluate catchment response to decreasing sulphate deposition. Sulphate deposition in the catchments studied declined by 38-82% during the last decade. Sulphate concentrations in all freshwaters decreased significantly, but acidification reversal was clearly delayed in the German streams. In Scandinavian streams and Czech/Slovakian lakes sulphate concentrations responded quickly to decreased input. Sulphate fluxes in run-off showed no clear trend in Germany and Italy but decreased in Scandinavia, the Czech Republic and Slovakia. The decrease, however, was less than the decline in input fluxes. While long-term sulphate output fluxes from catchments were generally correlated to input fluxes, most catchments started a net release of sulphate during the early 1990s. Release of stored sulphate leads to a delay of acidification reversal and can be caused by four major processes. Desorption and excess mineralisation were regarded as the most important for the catchments investigated, while oxidation and weathering were of lesser importance for the long-term release of sulphate. Input from weathering has to be considered for the Italian catchments. Sulphate fluxes in German catchments, with deeply weathered soils and high soil storage capacity, responded more slowly to decreased deposition than catchments in Scandinavia and the Czech Republic/Slovakia, which have thin soils and relatively small sulphate storage. For predictions of acidification reversal, soil characteristics, sulphur pools and their dynamics have to be evaluated in future research.
The MAGIC model of the responses of catchments to acidic deposition has been applied and tested extensively over a 15 year period at many sites and in many regions around the world. Overall, the model has proven to be robust, reliable and useful in a variety of scientific and managerial activities. Over the years, several refinements and additions to MAGIC have been proposed and/or implemented for particular applications. These adjustments to the model structure have all been included in a new version of the model (MAGIC7). The log aluminium ? pH relationship now does not have to be fixed to aluminium trihydroxide solubility. Buffering by organic acids using a triprotic analog is now included. Dynamics of nitrogen retention and loss in catchments can now be linked to soil nitrogen and carbon pools. Simulation of short-term episodic response by mixing fractions of different water types is also possible. This paper presents a review of the conceptual structure of MAGIC7 relating to long-term simulation of acidification and recovery, describes the conceptual basis of the new nitrogen dynamics and provides a comprehensive update of the equations, variables, parameters and inputs for the model.
Keywords: process-based model, acid deposition, recovery
A historical emission inventory for sulphur dioxide has been compiled for Europe covering the period 1880–1991. The estimated emissions have been used as input to the sulphur module of the EMEP/MSC-W acid deposition model. The aim was to show the way and the extent to which the historical development of anthropogenic sulphur dioxide emissions alone has affected the concentration and deposition fields of oxidised sulphur in Europe. Although acknowledged, effects exerted by the meteorological variability and the changing oxidising capacity of the atmosphere over the years have not been taken into consideration. Long-term emission estimates reveal that combustion of coal was the dominant emission source before World War II in all countries and combustion of liquid fuels thereafter in most. Releases from industrial processes were relatively small. National sulphur dioxide emissions peaked mainly in the 1960s and 1970s, whilst emission control measures resulted in gradual reductions in most countries in the 1980s. In Europe as a whole, coal combustion remained the major emission source throughout the century. Total anthropogenic releases increased by a factor of 10 between the 1880 s and 1970s when they peaked at approximately 55 million tonnes of sulphur dioxide, followed by a 30% decline in the 1980s. Uncertainties in national emission estimates due to uncertain sulphur contents in fossil fuels are within ± 30% for 22 out of 28 countries and ± 45% for the rest. The location of emission sources in Europe has shown over the years a progressive detachment from the coalfields towards a widespread distribution, accompanied in the last decades by considerable emission reductions over north-western and parts of central Europe and substantial increases in the south and south-east. Modelled air concentrations and depositions reflect to a great extent the emission pattern, revealing two- to six-fold increases between the 1880 s and 1970s. Maximum sulphur loadings are confined over parts of north-western and central Europe. Accumulated depositions over the period 1880–1991 in these areas reach 600 g (S) m −2 . Emissions are principally in the form of sulphur dioxide, so that comparable concentrations of particulate sulphate in low emission regions indicate the importance of long range transport. Assuming a constant ecosystem sensitivity throughout the period, depositions sufficient to cause ecosystem damage may have occurred before 1880 in many areas of north-western and central Europe. Nevertheless, in large parts of eastern and southern Europe depositions are still below these critical loads. DOI: 10.1034/j.1600-0889.1996.t01-2-00005.x
A 3-D Eulerian acid deposition model has been developed at MSC-W. The model has approximately 50 km horizontal resolution with 20 vertical layers, of which 10 are below 2 km. Meteorological input, from a dedicated weather prediction model, is updated at six-hour intervals. Emission inventories for SO 2 , NO x (NO + NO 2 ) and NH 3 , reported officially by individual countries, are used as input data. A brief description of the current model version is given, as well as the model results for sulphur compounds in 1992. We present a comparison of calculated and measured SO 2 and SO 4 annual (scatter plots) and daily concentrations (time-series) at selected locations in Europe.
Research in recent years has led to conceptualizations of the long-term
responses of catchment surface water quality to acidic deposition. That
research has focused attention on certain soil processes as likely keys
to catchment responses (anion retention, cation exchange, primary
mineral weathering, aluminum dissolution, and CO2
solubility). We present a mathematical model which uses quantitative
descriptions of these soil chemical processes to estimate the long-term
chemical changes that occur in the soil, soil water, and surface waters
of catchments in response to changes in atmospheric deposition. The
model is applied to a small forested catchment in the Shenandoah
National Park, Virginia. Historical changes in surface water quality are
reconstructed for the catchment for the last 140 years. The model
indicates that alkalinity of surface waters in the catchment may have
been reduced by as much as 50%. Water quality is forecast for the
catchment under three different scenarios of future changes in
atmospheric deposition. The model indicates that all but very large
reductions in deposition will result in further deterioration of the
catchment water quality. The process-oriented, lumped-parameter approach
used is consistent with all currently available observations of water
quality in the catchment. Due to the lack of long-term records of
catchment water quality, strict verification of the model estimates and
an assessment of the model validity is problematic. This is the case for
all models of long-terrn catchment chemical responses to acid
deposition. Nonetheless, the model provides a means of integrating the
results of individual process level laboratory and field studies. Used
this way, the model becomes a vehicle for examining the interactions and
long-term implications of our conceptualization of the acidification
process.
Quantitative predictions of the effects of acid deposition onterrestrial
and aquatic systems require physically based, process-oriented models of
catchment soil water and streamwater chemistry. A desirable
characteristic of such models is that they include terms to describe the
important phenomena controlling a system's chemical response to acidic
deposition, yet be restricted in complexity so that they can be
implemented on diverse systems with a minimum of a priori data. We
present an assessment of a conceptual model of soil water and
streamwater chemistry based on soil cation exchange, dissolution of
aluminum hydroxide, and solution of carbon dioxide, all processes that
occur in catchment soils and that have rapid equilibration times. The
model is constructed using an "average" or lumped representation of
these spatially distributed catchment processes. The adequacy of the
model is assessed by applying it to 3 years of soil water and
streamwater chemistry data from White Oak Run, Virginia, a second-order
stream in the Shenandoah National Park. Soil properties predicted by the
model are in good agreement with presently available measurements of
those soil properties. The success of the model suggests that lumped
representations of complex and spatially distributed chemical reactions
in soils can efficiently describe the gross chemical behavior of whole
catchments (e.g., pH, alkalinity, and major ionic concentrations in
surface waters). Further assessment of the adequacy of this conceptual
approach will require more detailed empirical knowledge of the soil
processes being modeled, particularly soil cation exchange and the
variability of soil CO2 partial pressures.
In a sample of 102 lakes in the Pyrenees, 68% were sensitive to acidification in varying degrees. A model which describes the regional alkalinity distribution by using random variables to represent lake alkalinity, chemical weathering and biological alkalinity generation, is proposed to calculate the alkalinity loss due to acid deposition, and the critical and target acid loads. This model is kept simple to reduce the input requirements and make the calibration procedures feasible on a regional scale. The relative simplicity of high mountain catchments lying above the tree line, in particular the lack of well developed soils, makes such a model appropriate for these environments. The loss in alkalinity since the start of large scale industrial emissions was estimated to be 35 mu eq l(-1) on average. Assuming a scenario of increasing nitrogen deposition, we estimate that a critical level of 10% of lakes with alkalinities below 20 mu eq l(-1) would be reached for a nitrogen deposition of 70-75 mu eq l(-1). According to the model, a 50% reduction of both nitrogen and sulphur deposition would be necessary to ensure that all lakes are above the critical level. (C) 1998 Elsevier Science Ltd. All rights reserved.
102 lakes distributed along the Catalan Pyrenees (from 0-degrees-41'E to 1-degrees-48'E) were sampled during summer in 1987. The alkalinity of the lakes was low (< 300 muequiv l-1) but there was no regional acidification. Most chemical variance was related to the nature of the bedrock. Lakes on Devonian, Cambro-Ordovician, Silurian or granodioritic batholites were easily distinguished. Even between different batholites, there were significant differences. There was no clear distinction either in the chemistry or in trophic status between disturbed and undisturbed lakes, except for certain extreme cases. Pasture is the most important source of eutrophication, but is restricted to small, very shallow and usually endorreic lakes.
1. We carried out a coordinated survey of mountain lakes covering the main ranges across Europe (including Greenland), sampling 379 lakes above the local tree line in 2000. The objectives were to identify the main sources of chemical variability in mountain lakes, define a chemical classification of lakes, and develop tools to extrapolate our results to regional lake populations through an empirical regionalisation or upscaling of chemical properties.
2. We investigated the main causes of chemical variability using factor analysis (FA) and empirical relationships between chemistry and several environmental variables. Weathering, sea salt inputs, atmospheric deposition of N and S, and biological activity in soils of the catchment were identified as the major drivers of lake chemistry.
3. We tested discriminant analysis (DA) to predict the lake chemistry. It was possible to use the lithology of the catchments to predict the range of Ca2+ and SO42− into which a lake of unknown chemistry will decrease. Lakes with lower SO42− concentrations have little geologically derived S, and better reflect the variations in atmospheric S loading. The influence of marine aerosols on lakewater chemistry could also be predicted from the minimum distance to the sea and altitude of the lakes.
4. The most remarkable result of FA was to reveal a factor correlated to DOC (positively) and NO3− (negatively). This inverse relationship might be the result either of independent processes active in the catchment soils and acting in an opposite sense, or a direct interaction, e.g. limitation of denitrification by DOC availability. Such a relationship has been reported in the recent literature in many sites and at all scales, appearing to be a global pattern that could reflect the link between the C and N cycles.
5. The concentration of NO3− is determined by both atmospheric N deposition and the processing capacity of the catchments (i.e. N uptake by plants and soil microbes). The fraction of the variability in NO3− because of atmospheric deposition is captured by an independent factor in the FA. This is the only factor showing a clear pattern when mapped over Europe, indicating lower N deposition in the northernmost areas.
6. A classification has been derived which takes into account all the major chemical features of the mountain lakes in Europe. FA provided the criteria to establish the most important factors influencing lake water chemistry, define classes within them, and classify the surveyed lakes into each class. DA can be used as a tool to scale up the classification to unsurveyed lakes, regarding sensitivity to acidification, marine influence and sources of S.
A model, MAKEDEP, was developed for reconstructing historic atmospheric deposition and nutrient uptake for forests using present day values. Deposition is reconstructed by separation of wet deposition and throughfall into five different categories. Dry deposition is assumed to depend linearly on needle biomass. Non-marine deposition is scaled using general European emission and deposition trends for sulphur, nitrate and ammonia. Historic nutrient uptake is reconstructed using current biomass and nutrient content, a logistic forest growth curve and information on historic land use.
Soils and lakes were sampled in fifteen catchments in the alpine zone of the Tatra Mountains (Slovak-Polish border) to evaluate the dependence of lake water chemistry on soil properties. The amount of soil in alpine meadows varied from 38 to 255 kg m -2 (dry weight soil <2 mm; average of 121 kg m -2). The average cation exchange capacity (CEC) was 12 eq m -2, average base saturation was 12%, and average pH CaCl2, was 4.0. Moraine areas had, on average, 13 kg m -2 of <2 mm soil in small deposits between stones. Their chemical properties were similar to mineral horizons of alpine soils but had higher concentrations of P forms. Soil composition was spatially uniform, having coefficients of variation of all parameters between 5 and 115%, and did not exhibit significant differences between the catchments or along the elevation gradient. Variation in pools of soil constituents was ∼2-fold higher. Soil organic matter concentration was the parameter that most strongly and positively correlated with N, P, S, CEC, exchangeable base cations, exchangeable acidity, and all biochemical parameters (C, N, and P in microbial biomass and C and N mineralisation rates). Lake water concentrations of organic C, N, and total P were positively correlated (P < 0.01) with the pool of soil organic matter in the catchments, while NO 3- concentrations were negatively correlated (P < 0.001). No correlations were found between C, N, and P concentrations in lakes and soil chemistry, indicating the dominant role of soil quantity over quality for surface water composition in the Tatra lakes. Relatively high concentrations of Ca 2+, Na +, SO 42-, reactive Si, and acid neutralising capacity in some lakes were not explained by soil characteristics, and were more probably related to bedrock composition and structure.
Bulk precipitation samples from four locations in the Pyrenees were analysed for major ions and nutrients. The chemical composition of precipitation was related to the origin of storms. Rains coming from the Mediterranean Sea (south-southeast) were alkaline, while those from the Atlantic (northwest) were more acidic. The situation and particular orography of each sampling point determine the amount of precipitation received from each direction and, therefore, the chemical features of rain at each location. We detected differences in the acid loading among the four sampling sites. Bulk precipitation in the Pyrenees is more alkaline than precipitation in central Europe (Alps), owing to the higher Ca2+ concentrations and the lower acid pollutant levels (SO42− and NO3−) found in the Pyrenees.
Acid rain! Dead fish! Forest dieback! In the 1980s and 1990s, these headlines appeared frequently in environmental news coverage in Europe and North America. Air pollutants from highly industrialized regions had caused widespread damage to pristine ecosystems far downwind. The victims-people living in regions such as eastern Canada and Norway-pressured the polluters. In Europe, 30 countries engaged in tough negotiations that finally resulted in international treaties to reduce the emissions of sulfur and nitrogen oxides. Acid deposition has now declined by similar to60%, and some lakes and streams have begun to recover. Will all waters recover, or must emissions be reduced even more? And how long will recovery take? In this article, we try to answer these questions by using models to predict future acidification of surface waters in 12 acid-sensitive regions in Europe.
The MAGIC model was used to evaluate the relative sensitivity of several possible climate-induced effects on the recovery of soil and surface water from acidification. A common protocol was used at 14 intensively studied sites in Europe and eastern North America. The results show that several of the factors are of only minor importance (increase in pCO(2) in soil air and runoff, for example), several are important at only a few sites (seasalts at near-coastal sites, for example) and several are important at nearly all sites (increased concentrations of organic acids in soil solution and runoff, for example). In addition changes in forest growth and decomposition of soil organic matter are important at forested sites and sites at risk of nitrogen saturation. The trials suggest that in future modelling of recovery from acidification should take into account possible concurrent climate changes and focus specially on the climate-induced changes in organic acids and nitrogen retention.
Estudio de la dinámica hidro-biogeoquímica y balances de masa elementales en cuencas de alta montaña: una aproximación a algunos aspectos del ciclo del carbono
- M Altuna
Altuna M. Estudio de la dinámica hidro-biogeoquímica y balances de masa elementales en cuencas de alta montaña: una aproximación a algunos aspectos del ciclo del carbono. M. Sc. Thesis, Universitat de Girona, 2006, 113 pp.
Cost-effective control of acidification and ground-level ozone. Second Interim Report to the European Commission, DG XI. IIASA; 1996. December, 112 pp. Camarero L, Catalan J. Chemistry of bulk precipitation in the Central and Eastern Pyrenees (Northeast Spain)
- M Amann
- I Bertok
- Gyarfas J F Cofala
- Heyes C Z Klimont
Amann M, Bertok I, Cofala J, Gyarfas F, Heyes C, Klimont Z, et al. Cost-effective control of acidification and ground-level ozone. Second Interim Report to the European Commission, DG XI. IIASA; 1996. December, 112 pp. Camarero L, Catalan J. Chemistry of bulk precipitation in the Central and Eastern Pyrenees (Northeast Spain). Atmos Environ 1993;27A:83–94.
Trends of sulphur dioxide emissions, air concentrations and depositions of sulphur in Europe since 1880 Oslo: The Norwegian Meteorological Institute Altitude zonation in the Pyrenees. A geobotanic interpretation
- S Mylona
- Jm Ninot
- E Carrillo
- Carreras X J Font
- A Ferré
- Masalles Rm
Mylona S. Trends of sulphur dioxide emissions, air concentrations and depositions of sulphur in Europe since 1880. EMEP/MSC-W Report 2/93. Oslo: The Norwegian Meteorological Institute; 1993. 99 pp. Ninot JM, Carrillo E, Font X, Carreras J, Ferré A, Masalles RM, et al. Altitude zonation in the Pyrenees. A geobotanic interpretation. Phytocoenologia 2007;37:371–98.
Status of European critical loads and dynamic modelling
- J-P Hettelingh
- M Posch
- Slootweg
- M Posch
- J-P Hettelingh
- J Slootweg
- Downing
Hettelingh J-P, Posch M, Slootweg J. Status of European critical loads and dynamic modelling. In: Posch M, Hettelingh J-P, Slootweg J, Downing RJ, editors. Modelling and Mapping Of Critical Thresholds In Europe, CCE Status Report, 2003. RIVM Report 259101013. Bilthoven: RIVM; 2003. p. 1–10.
Regionalisation of chemical variability in European mountain lakes A spectral approach to model mountain lake catchment through landscape attributes
- Rogora M R Mosello
- Anderson J A Barbieri
- I Botev
Camarero L, Rogora M, Mosello R, Anderson J, Barbieri A, Botev I, et al. Regionalisation of chemical variability in European mountain lakes. Freshwater Biol, in press. Casals-Carrasco P, Catalan J, Madhavan B, Gond V. A spectral approach to model mountain lake catchment through landscape attributes. Proc. SPIE Int. Soc. Opt. Eng. 2004;5239:145–64.
Methods of Soil Analysis, Part 2
- Thomas Gw Exchangeable
Thomas GW. Exchangeable cations. In: Page AL, Miller RH, Keeney DR, editors. Methods of Soil Analysis, Part 2. Agron. Soc. Amer. and Soil Sci. Soc. Amer., 2nd ed.Madison; 1982. p. 159–66.
Trends of sulphur dioxide emissions, air concentrations and depositions of sulphur in Europe since 1880 Oslo: The Norwegian Meteorological Institute
- S Mylona
Mylona S. Trends of sulphur dioxide emissions, air concentrations
and depositions of sulphur in Europe since 1880. EMEP/MSC-W
Report 2/93. Oslo: The Norwegian Meteorological Institute;
1993. 99 pp.
Status of European critical loads and dynamic modelling
- Hettelingh