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The biogeochemistry of two forested catchments in the Black Forest and the eastern Ore Mountains (Germany)
Abstract
The biogeochemical input-output fluxes of two forested catchments with contrasting levels of atmospheric deposition were investigated in Germany. This paper focuses on the effects of recent changes in atmospheric inputs on the chemical composition in the soil solution and stream. The catchment 'Schluchsee' (Black Forest; SW Germany) is characterized by relatively low atmospheric inputs whereas 'Rotherdbach' (Ore Mountains; E Germany) received significant amounts of acid deposition (mainly originating from SO2 emissions) until recent years. Both sites reveal decreases in H+ and S deposition during the 1990s. This pattern is typical when compared to trends in Europe. In response to the reduced S deposition, soil solution and streamwater SO4
2– concentrations decreased significantly. A net release of SO4
2– (output > input) was observed at both sites due to the release of S previously stored in the soil. The level of N deposition was more or less constant at both sites. At Schluchsee, NO3
– concentration in streamwater remained more or less unchanged, whereas a decrease at Rotherdbach was observed. A recovery from acidification was found in seepage water as indicated by increasing acid neutralizing capacity (ANC). Streamwater ANC increased only in the permanently acidified Rotherdbach. No change of ANC was observed in the Schluchsee stream, which was characterized by episodic acidification during high-flow conditions. Nevertheless, the key factor controlling the recovery from surface water acidification was the type, amount and distribution of stored S pools in the ecosystem. Thus, time series analysis of long-term data of input-output chemistry can be a valuable instrument in order to improve the understanding of linked terrestrial-aquatic systems and give useful clues for modeling efforts.
... Veselý et al. (2002) monitored numerous streams of Czech mountain regions (including parts of SE Erzgebirge) in 1985 and 12 years later, and found significantly increasing medians of pH up to one unit in waters with initial pH below 5. Kopá cek et al. (1998Kopá cek et al. ( , 2002 reported from lakes of the Bohemian Mountains and High Tatra Mountains (Slovakia, Poland) decreasing sulfate and nitrate loading, a decrease of Ca, Mg, and Al leaching from the watershed, and an increase in lake water pH and alkalinity, illustrating rapid reversal from acidification patterns in non-limed forest regions. In the Erzgebirge, Armbruster et al. (2003) observed only weak changes of stream water acidity in contrast to Lorz and Schneider (2003), who described rising pH trends especially since 1998. In summary, recent studies have shown considerable variability of hydrochemical trends, thus regional extrapolation of the results might be equivocal. ...
... At Lysina watershed (Slavkov Forest, NW Czech Republic) located w30 km south from the Erzgebirge and similarly affected by air pollution and acidification, the sulfur bulk deposition diminished by w75% from 85e 110 mmol m ÿ2 a ÿ1 in the early 1990s to 20e30 mmol m ÿ2 a ÿ1 in the early 2000s . At the end of the 1980s, sulfur deposition was 2e4 times higher in the Erzgebirge than in the northern Black Forest, where Thies (1994) measured bulk deposition and throughfall of 32 and 120 mmol m ÿ2 a ÿ1 , the latter value being w3 times higher than in the SE Black Forest (Armbruster et al., 2003). The concentrations of air NO 2 and NO as well as the wet-only inorganic nitrogen (NO 3 ÿ -N C NH 4 C -N) deposition rates remained almost constant at 90 G 14 mmol m ÿ2 a ÿ1 between 1993 and 2003. ...
... Nearly all of the investigated surface waters shifted to the next lower acidification stage within the study period. This general observation is contrary to the permanently acidified Rotherdbach (NE Erzgebirge) which showed no trend in the stream water pH between 1995 and 1999 in spite of increasing ANC (Armbruster et al., 2003). Elevated concentrations of inorganic Al (48e150 mmol L ÿ1 ) and of weak organic acids (both capable of protonation and deprotonation ...
Strongly decreasing atmospheric emissions and acidic deposition during the 1990s have initiated chemical reversal from acidification
in several drinking-water reservoirs of the Erzgebirge, SE Germany. We studied responses of phytoplankton, zooplankton and
fish stocks in five reservoirs and at enclosure scale after experimental neutralization of 1,200m3 of lake water. About 4months after this treatment, diatoms and cryptomonads replaced the predominating chrysophytes and
dinoflagellates. The colonization by acid-sensitive species of green algae, cryptomonads, rotifers and Cladocera (e.g. Bosmina longirostris) is explained by the occurrence of dormant stages or by survival of individuals in very low abundances. Analogous to the
enclosure experiment, three reservoirs showed significantly (p < 0.01) falling trends of chlorophyll a and phytoplankton biovolume, mainly due to the decline of dinoflagellates. Picoplankton and diatoms increased slightly in
two reservoirs. The zooplankton communities were dominated by rotifers and small Cladocera. Representatives of the genus Daphnia were lacking. Two reservoirs were re-colonized by zooplanktivorous fish populations of either perch (Perca fluviatilis) or sunbleak (Leucaspius delineatus). The latter exhibited extremely high fluctuating abundance and biomass and even suffered from a population crash. This natural
mortality was caused by a limited food supply. Hence, severe top-down control may delay the recovery of larger zooplankton
species like daphnids. Fishery management comprising the introduction of predatory fishes can help to control zooplanktivorous
fish populations and to prevent their mass mortality.
... Burning ashes, which are rich in minerals, oxides, and other compounds, lead to acidification and increased concentrations of Cland SO 4 2in the precipitation water (Armbruster et al., 2003). The increased atmospheric particle loading explains the differences between the levels of anions in the rainwater over the months, especially for Cland SO 4 2- (Table 1). ...
... Large amounts of NO 3 -, SO 4 2-, and Clin rainwater are a consequence of anthropogenic emissions, which contributed to the increase in air pollution (Armbruster et al., 2003); however, the vegetation burning are also responsible for the increased concentration of anions, such as sulfate, chloride, and nitrate, in the atmosphere, which modifies the chemical composition of the incident rainfall. ...
Rainfall is one of the primary nutrient inputs to vegetation and its chemical composition is dependent on air quality as falling rain scavenges gaseous and particulate emissions from natural, industrial, and agricultural activities. The objective of this study was to evaluate whether the vegetation burn in a region of the Pampa biome influences the pH and chemical composition (anions) in incident rainfall. Nitrate, sulfate, and chloride concentrations, as well as the pH of the rainwater, were influenced by suspended particles in the atmosphere from biomass burning of native grassland and pasture renewal. The rainwater was acidified by, ash, and soot, which introduced large amounts of chloride and sulfate into the ecosystems caused by burning vegetation.
... Abweichende Ergebnisse weisen insbesondere für den Standort 1405 auf andere, im Modell nicht berücksichtigte Einflussgrößen hin, z. B. auf eine erhöhte Stickstoffaufnahme durch das Ökosystem [12]. ...
... Ausgeglichene Bilanzen können auch eine hohe Variabilität der Standortbedingungen widerspiegeln. Im Grundwasserkörper EL 1-10 wird die relativ hohe Immissionsbelastung durch landwirtschaftliche Nutzung im nordwestlichen Teil verursacht, die hohe Emissionsbelastung beruht auf erhöhten atmosphärischen N-Depositionen im südöstlichen bewaldeten Teil des Grundwasserkör-pers. Im Waldökosystem ist der Zustand der Stickstoffsättigung bereits erreicht, im Grundwasser wurden bisher (noch) keine erhöhten Nitratkonzentrationen festgestellt [12]. ...
The European Water Framework Directive requires the assessment of the impact of diffuse sources (pressures) into the groundwater. In Saxony the assessment was carried out with the balance model STOFFBILANZ. The balance considers atmospheric deposition, anthropogenic nitrogen input by agricultural and urban land use, and denitrification of the soil zone. The potential amount of the teachable nitrogen surplus was evaluated for Saxonian groundwater bodies. The methodology allows a rough estimate of the nitrogen emission. It will be rendered more precisely while the further implementation of the WFD.
... Abweichende Ergebnisse weisen insbesondere für den Standort 1405 auf andere, im Modell nicht berücksichtigte Einflussgrößen hin, z. B. auf eine erhöhte Stickstoffaufnahme durch das Ökosystem [12]. ...
... Ausgeglichene Bilanzen können auch eine hohe Variabilität der Standortbedingungen widerspiegeln. Im Grundwasserkörper EL 1-10 wird die relativ hohe Immissionsbelastung durch landwirtschaftliche Nutzung im nordwestlichen Teil verursacht, die hohe Emissionsbelastung beruht auf erhöhten atmosphärischen N-Depositionen im südöstlichen bewaldeten Teil des Grundwasserkör-pers. Im Waldökosystem ist der Zustand der Stickstoffsättigung bereits erreicht, im Grundwasser wurden bisher (noch) keine erhöhten Nitratkonzentrationen festgestellt [12]. ...
Für die Beurteilung diffuser Schadstoffbelastungen des Grundwassers nach der Europäischen Wasserrahmenrichtlinie wurden in Sachsen Stickstoff-Flächenbilanzierungen nach dem Modell
STOFFBILANZ durchgeführt. Die Bilanzierungen berücksichtigen die atmosphärische Deposition, anthropogene Stickstoffeinträge durch landwirtschaftliche Nutzungen in Siedlungsgebieten sowie
die Denitrifikation in der Bodenzone. Für jeden Grundwasserkörper wurden die mit dem Sickerwasser potenziell auswaschbaren Stickstoffüberschüsse nutzungsbezogen abgeschätzt.
... A major trigger for this development came by the political and economical change in the states of Central and Eastern Europe since the end of the 1980s. Emissionintensive lignite based power generation in these countries dropped rapidly leading to a decreased acid deposition (Armbruster et al., 2003; Zemek et al., 2006). Additionally, large-scale forest soil liming was performed (Ulrich et al., 2006 ). ...
... With respect to the source of nitrate in our system, this may depend on the nitrate load in the tributary water flows which in turn is a function of nitrogen release in the catchment area. Regarding the high deposition rates in the past (Zimmermann et al., 2003), Armbruster et al. (2003 showed nitrogen saturation (Stoddard and Traaen, 1995 ) for our research area in the period 1995 to 1999 followed by a decrease in nitrogen output. This was caused by reduced deposition and a recovered vitality related increased nutrient retention in the forest stands. ...
... Since then, fertilizer use declined drastically, initiated by federal regulations of Saxony which came into effect in 1994. Another possible explanation for decreasing trends in the Ore Mountains is a higher N uptake as a result of extensive reforestation and the continuous recovery and increasing vitality of damaged forests (Ulrich et al. 2006), which, according to Armbruster et al. (2003), could also explain the large NO − 3 decrease of stream 23 (−8.87 μmol c l −1 year −1 ). Regardless of the landuse impact, the majority of streams in the Ore Mountains and the Fichtelgebirge (region 1) show significant negative trends (Fig. 3). ...
... De-icing salts applied to roads in winter can influence the concentration additionally, as was reported for example for stream no. 23 (Armbruster et al. 2003). ...
This study evaluates the acidification status and trends in streams of forested mountain ranges in Germany in consequence of reduced anthropogenic deposition since the mid 1980s. The analysis is based on water quality data for 86 long-term monitored streams in the Ore Mountains, the Bavarian Forest, the Fichtelgebirge, the Harz Mountains, the Spessart, the Black Forest, the Thuringian Forest, and the Rheinisches Schiefergebirge of Germany and the Vosges of France. Within the observation period, which starts for the individual streams between 1980 and 2001 and ends between 1990 and 2009, trends in chemical water quality were calculated with the Seasonal Mann Kendall Test. About 87% of the streams show significant (p < 0.05) negative trends in sulfate. The general reduction in acid deposition resulted in increased pH values (significant for 66% of the streams) and subsequently decreased base cation concentrations in the stream water (for calcium significant in 58% and magnesium 49% of the streams). Reaction products of acidification such as aluminum (significant for 50%) or manganese (significant for 69%) also decreased. Nitrate (52% with significant decrease) and chloride (38% with significant increase) have less pronounced trends and more variable spatial patterns. For the quotient of acidification, which is the ratio of the sum of base cations and the sum of acid anions, no clear trend is observed: in 44% of the monitored streams values significantly decreased and in 23% values significantly increased. A notable observation is the increasing DOC concentration, which is significant for 55% of the observed streams.
... Other studies have reported a delay or even no reaction in respect to water acidification, which was attributed to the release of previously stored sulfate from developed soils, coupled to the leaching of aluminum (Al) and base cations (BC; e.g. Alewell et al. 2000a;Prechtel et al. 2001;Armbruster et al. 2003). Chronic high atmospheric input of nitrogen (N) also leads to a net acidification in N-rich forest ecosystem, where inorganic N (mostly NO − 3 ), exceeding the plant and microbe demand, is leached below the root zone (Gundersen et al. 2006). ...
... Trend analyses in soil solution collected in forest ecosystems were performed in several countries in Europe in the late 1980s and in the 1990s such as in Belgium (Neirynck et al. 2002), Germany (e.g. Meesenburg et al. 1995;Alewell et al. 2000b;Armbruster et al. 2003), Norway Moffat et al. 2002), Sweden (Fölster et al. 2003), and Switzerland (Blaser et al. 1999). Later, the studies of Boxman et al. (2008), Oulehle et al. (2006), and Neirynck et al. (2008) reported longterm trends of the soil solution chemistry until 2005-2007 at single forest plots. ...
Trends in atmospheric acid deposition and in soil solution acidity from 1995 or later until 2007 were investigated at several forest sites throughout Switzerland to assess the effects of air pollution abatements on deposition and the response of the soil solution chemistry. Deposition of the major elements was estimated from throughfall and bulk deposition measurements at nine sites of the Swiss Long-Term Forest Ecosystem Research network (LWF) since 1995 or later. Soil solution was measured at seven plots at four soil depths since 1998 or later. Trends in the molar ratio of base cations to aluminum (BC/Al) in soil solutions and in concentrations and fluxes of inorganic N (NO(3)-N + NH(4)-N), sulfate (SO(4)-S), and base cations (BC) were used to detect changes in soil solution chemistry. Acid deposition significantly decreased at three out of the nine study sites due to a decrease in total N deposition. Total SO(4)-S deposition decreased at the nine sites, but due to the relatively low amount of SO(4)-S load compared to N deposition, it did not contribute to decrease acid deposition significantly. No trend in total BC deposition was detected. In the soil solution, no trend in concentrations and fluxes of BC, SO(4)-S, and inorganic N were found at most soil depths at five out of the seven sites. This suggests that the soil solution reacted very little to the changes in atmospheric deposition. A stronger reduction in base cations compared to aluminum was detected at two sites, which might indicate that acidification of the soil solution was proceeding faster at these sites.
... The similar trends of Mg and Ca in bulk and throughfall precipitation were observed also at the Rotherdbach watershed (Germany) in the Ore Mountains, where Ca decreased by 0.2 kg ha − 1 year − 1 in bulk deposition and 0.46 kg ha − 1 year − 1 in throughfall in the period 1995-1999. Time series analysis yielded no significant decrease in Mg deposition (Armbruster et al., 2003). ...
... Similarly, at the Rotherdbach watershed situated ca 60 km northeast of Načetín, the NO 3 − concentration in soil water decreased significantly during the past years (Armbruster et al., 2003), as well as in stream water at Rotherdbach and at a majority of drinking water reservoirs and their tributaries on the German side of the Ore Mts. (Ulrich et al., 2006). ...
During the 1990s the emissions of SO(2) fell dramatically by about 90% in the Czech Republic; the measured throughfall deposition of sulphur to a spruce forest at Nacetín in the Ore Mts. decreased from almost 50 kg ha(-1) in 1994 to 15 kg ha(-1) in 2005. The throughfall flux of Ca decreased from 17 kg ha(-1) in 1994 to 9 kg ha(-1) in 2005; no change was observed for Mg. The deposition of nitrogen ranged between 15 and 30 kg ha(-1) with no statistically significant trend in the period 1994-2005. The desorption of previously stored sulphur and the decrease of Ca deposition are the main factors controlling the recovery of soil solution. The pH of the soil solution at a depth of 30 cm remains unchanged, and the Al concentration decreased from 320 micromol l(-1) in 1997 to 140 micromol l(-1) in 2005. The enhanced leaching of base cations relative to no acidified conditions has continued, although the Ca concentration decreased from 110 microeq l(-1) in 1997 to 25 microeq l(-1) in 2005 in the mineral soil solution at 30 cm depth. This dramatic change was not observed for Mg concentration in soil solution, because its deposition remained stable during the observed period. Similar patterns were observed in the deeper soil solution at 90 cm. The reduction in Ca availability resulted in lower uptake by tree assimilatory tissues, measured as concentration in needles. Since 2005, the leaching of nitrate observed in soil solution at 30 cm depth has disappeared. By 2003 a similar situation occurred at 90 cm. Higher incorporation into the trees after 1997 could be an important factor. With respect to the formerly high sulphur deposition and consequently released aluminium, which could have negatively influenced the biotic immobilization driven by microbes and fungi, the recovery may have positively impacted and therefore improved retention in the ecosystem during recent years. The delay in the successful retention of nitrogen in the ecosystem was probably caused by the high mineralization of organic matter after improvement of chemical parameters in the organic horizon (increase in pH and decrease in Al concentration). It seems that high mineralization of stored organic matter after decades of high acidic deposition could be an important factor affecting the high losses of nitrogen in spruce forest ecosystems.
... Due to the filtering of emission gases from combustion, deposition loads strongly declined in the last decades [3], and liming measures were carried out to buffer the acid pollution in forest soils [12]. Nevertheless, legacy effects of former high sulfur (S) depositions were observed in ecosystems over many years, because of long-term storage of S within the organic layer and mineral soil [13][14][15][16]. In the last decade, these legacy effects have been observed to diminish. ...
During the last decades, forest soils in Central Europe recovered from former sulfur and acid deposition. As external S input into forests has strongly decreased and legacy S pools in the soils are diminishing, internal S cycling through mineralization will increasingly become important for ecosystem nutrition. However, it is not known how microbial biomass is affected by the S pool change in the formerly S surplus soils. Here, we present data on the status quo of C, N, and S in microbial biomass in relation to contents in mineral soil and organic layer. The results of forest soil in Eastern Germany (low and high liming), which is slowly recovering from former pollution, are compared to those of a site remote from air pollution in the Swiss Alps. The contents of C, N, and S in soil as well as in microbial biomass were clearly higher in the organic layer than in mineral topsoil at all sites. Despite the generally low content in the mineral A-horizon, the clean-air site showed indications of a more active S-turnover as compared to the high-pollution site. Liming at the high-pollution site improved the conditions for microbial growth (pH increase) in the organic layer resulting in more mobile S.
... The similar share of Na + and Cl − in the ionic composition of the stream water and both groundwater sites in the Wüstebach catchment, analogous to the brines (Figure 3), indicates that de-icing salts spread from the road to the stream at a distance of at least 300 m. The strong and long-term effect of using de-icing salt on increasing sodium and chloride concentrations in stream water was also found in other catchments in Germany [39] and around the world [40,41]. Kelly et al. [41] showed that despite the lack of increasing use of de-icing salt in the catchment, the concentration of chloride in the stream water was systematically increasing. ...
To ensure the good chemical status of surface water across Europe, it is necessary to increase research on the comprehensive impact of land use and land cover changes, i.e., deforestation, on the natural environment. For this reason, we used data from 9-year environmental monitoring in the Wüstebach experimental catchment of the TERENO (Terrestrial Environmental Observatories) network to determine the impact of partial deforestation on solute fluxes and stream water ionic composition. In 2013, a partial deforestation experiment was conducted in the study area using a cut-to-length logging method. To this end, two headwater catchments were compared: one partially deforested (22% of the catchment area) and one untreated control catchment. The concentrations of ions in stream water, groundwater, and precipitation were analyzed: Ca2+, Mg2+, Na+, K+, Al3+, Fetot, Mn2+, NO3−, SO4−, and Cl−. Most of the ions (Na+, Ca2+, Mg2+, Cl−, and SO4−) showed decreasing trends in concentrations after deforestation, indicating a dilution effect in stream water due to the reduction of the supply of solutes with precipitation in the open deforested area. The fluxes of these ions decreased by 5–7% in the first year after deforestation, although the stream runoff increased by 5%. In the second year, the decrease in ion fluxes was greater, from 6% to 24%. This finding confirms that only limited soil erosion occurred after the deforestation because the soil was well protected during logging works by covering harvester lanes with branches. Only K+ and NO3− ions showed increasing trends in both concentrations and fluxes in the partially deforested catchment in the first two to three years after deforestation. Spruce die-offs, common in Europe, may decrease the concentration and fluxes of base cations in surface water in a nutrient-limited environment. However, the simultaneous planting of young broad-leaved trees with post-harvesting regrowth could create a nutrient sink that protects the catchment area from nutrient depletion.
... As shown by Novak et al. (2005) using sulfur isotope ratios ( 34 S : 32 S), cycling of the high amounts of deposited SO x at UDL occurred not only by adsorption/desorption of SO 2− 4 onto soil particles, but also, to a great extent, by cycling through the soil organic matter. As a consequence, acidification and export of SO 2 4 , and for that matter, legacy reactive N, may prevail for several decades in the UDL as well as other similarly polluted mountain catchments (Novak et al., 2000;Armbruster et al., 2003;Mörth et al., 2005). Similarly, in UDL decreased runoff NO − 3 export seems to be rather controlled by biological processes than by catchment hydrology (Oulehle et al., 2017). ...
We collected soil solutions by suction lysimeters in a
central European temperate forest with a history of acidification-related
spruce die-back in order to interpret spatial patterns of soil nutrient
partitioning, compare them with stream water chemistry and evaluate these
parameters relative to concurrent loads of anions and cations in
precipitation. Five lysimeter nests were installed in the 33 ha U dvou
loucek (UDL) mountain catchment at different topographic positions
(hilltops, slopes and valley). Following equilibration, monthly soil
solution samples were interrogated over a 2-year period with regard to their
SO42-, NO3-, NH4+, Na+, K+, Ca2+,
Mg2+ and total dissolved Al concentrations, organic carbon (DOC) and
pH. Soil pits were excavated in the vicinity of each lysimeter nest to also
constrain soil chemistry. For an estimation of phosphorus (P) availability,
ammonium oxalate extraction of soil samples was performed. Cation exchange
capacity (CEC ≤58 meq kg−1) and base saturation (BS ≤13 %) were found to be significantly lower at UDL than in other monitored
central European small catchments areas. Spatial trends and seasonality in
soil solution chemistry support belowground inputs from mineral-stabilized
legacy pollutants. Overall, the soil solution data suggest that the
ecosystem was still chemically out of balance relative to the concurrent
loads of anions and cations in precipitation, documenting incomplete
recovery from acidification. Nearly 30 years after peak acidification, UDL
exhibited similar soil solution concentrations of SO42, Ca2+ and Mg2+ as median values at the Pan-European International
Co-operative Program (ICP) Forest sites with similar bedrock lithology and
vegetation cover, yet NO3- concentrations were an order of
magnitude higher. When concentrations of SO42-, NO3- and
base cations in runoff are compared to soil pore waters, higher
concentration in runoff points to lateral surficial leaching of pollutants
and nutrients in excess than from topsoil to subsoil. With P availability
being below the lowest range observed in soil plots from the Czech Republic,
the managed forest ecosystem in UDL probably reflects growing inputs of C
from regenerating vegetation in the N-saturated soil, which leads to P
depletion in the soil. In addition, the observed spatial variability
provides evidence pointing to substrate variability, C and P
bioavailability, and landscape as major controls over base metal leaching
toward the subsoil level in N-saturated catchments.
... Conversely, export of total inorganic N from UDL via stream runoff continues to be significantly lower than its atmospheric input (Oulehle et al., 2017). As shown by Novak et al. (2004) using sulfur isotope ratios ( 34 S/ 32 S), cycling of the high amounts of deposited SOx at 20 UDL occurred not only by adsorption/desorption of SO4 2on soil particles, but, to a great extent, also by cycling through the soil organic matter, which may prevail for several decades (Novak et al., 2000;Armbruster et al., 2003;Mörth et al., 2005). ...
In order to interpret spatial patterns of soil nutrient partitioning and compare these with runoff in a temperate forest with a history of acidification-related spruce die-back, the chemistry of mineral soil solutions were collected by suction lysimeters and evaluated relative to concurrent loads of anions and cations in precipitation. Lysimeters nest were installed in the 33-ha U dvou loucek (UDL) mountain catchment at different topographic positions (hilltops, slopes and valley). Following equilibration, monthly soil solution samples were collected over a 2-year period. In the vicinity of each lysimeter nest, soil pits were excavated for constraining soil chemistry. Soil solutions were analyzed for SO42−, NO3−, NH4+, Na+, K+, Ca2+, Mg2+, and total dissolved Al concentrations and organic matter (DOC), and pH. For a P release estimation, ammonium oxalate extraction of soil samples was performed. Comparison of soil water data with other previously acidified monitored European sites indicated that environmentally relevant chemical species at UDL had concentrations similar to median concentrations observed in sites with similar bedrock lithology and vegetation cover. Cation exchange capacity (CEC ≤ 58 meq kg−1) and base saturation (BS ≤ 13 %), however, were significantly lower at UDL, documenting incomplete recovery from acidification. Spatial trends and seasonality in soil water chemistry support belowground inputs from mineral-stabilized legacy pollutants. Overall, the soil-solution data suggest the system is out of balance chemically, relative to the present loads of anions and cations in precipitation. Higher concentrations of SO42−, NO3−, and base cations in runoff than in soil solutions are explained by lateral surficial leaching of pollutants and nutrients from shallow soil horizons. Nearly 30 years after peak acidification, UDL exhibited similar soil solution concentrations of SO42, Ca2+ and Mg2+ as median values at the Pan-European International Co-operative Program (ICP) Forest sites, yet NO3− concentrations were an order of magnitude higher.
... Lakkasuo is also located in the cold climate zone, with no dry seasons and cold summers (Dfc zone, based on the Köppen-Geiger climate classification; Peel et al., 2007). The ditches that were installed in 1961 (70 cm depth; spacing of 40-60 m) affect approximately 50 % of the peatland (Minkki -Table 2. Overview of studied mires, coordinates (latitude/longitude), mean annual temperature (MAT), annual precipitation (P ), and Sphagnum mosses (Sph.; Laine et al., 2004;Nilsson et al., 2008;DWD, 2018;Alexandersson et al., 1991;Armbruster et al., 2003). ...
For centuries European peatlands have been degrading along with drainage, land use and climate changes. Increasing pressure on peatland ecosystems calls for a more cost-efficient method to indicate the current state of peatlands and the success of restoration efforts. Metabolic pathways in peatland soils are imprinted in stable isotope compositions due to differences in microorganism communities and their metabolic pathways. Therefore, we hypothesize that depth profiles of nitrogen stable isotope values provide a promising opportunity to detect peatland decomposition or restoration. We studied five peatlands, namely Degerö Stormyr (northern Sweden), Lakkasuo (central Finland) and three mires in the Black Forest (southern Germany). At all locations, cores were taken from adjacent drained (or rewetted) and natural sites to identify δ15N trends that could indicate changes due to drainage and restoration. At all drained (and rewetted) sites we found a distinct peak (“turning point”) of the δ15N values in the center of the drained horizon. We did a fatty acids (FAs) analysis to link our results to microbial community composition. As markers, we distinguished between one fungal-derived FA (C18:2ω9c) and four bacterial-derived FAs. For bacteria, we looked for one general bacterial-derived FA (C14:0), two FAs for gram-positive bacteria (i-C15:0; a-C15:0), and one FA for gram-negative bacteria (C16:1ω9c). In accordance with other studies, our results suggest that fungi dominate the microbial metabolism in the upper aerobic peat horizon. This is reflected by depleted δ15N values. Moving downwards, the drained horizon conditions slowly switch to oxygen limitation. Consequently, fungal-derived FAs decrease whereas bacterial-derived FAs rise. The highest diversity of microbial-derived FAs is indicated by the δ15N turning point. Below the δ15N turning point, oxygen is increasingly limited and concentrations of all microbial-derived FAs are decreasing down to the onset of the permanently waterlogged anaerobic horizon. Peatland cores with restoration successes again show, above the formerly drained horizon, no depth trend of the isotopic values. Hence, we conclude that δ15N stable isotope values reflect microbial community composition, which differs between drained and natural peatlands.
... A specific geochemical signal from potash production cannot be expected as the main component KOH is easily soluble therefore not accumulated in the sediment. We also neglected S as it has been massively introduced into the soils of the region by intensified lignite firing in Bohemia since the 1940s that caused severe forest dieback (Armbruster et al. 2003). Quartz raw material and glass slags have been analyzed by wavelength-dispersive spectrometry (WDS) using a JXA 8230 and JXA 8500F electron microprobe with 15 kV, 20 nA and a 20 μm probe size. ...
Since the twelfth century, forest areas in the upper reaches of the low mountain ranges of central Europe provided an important source of wood and charcoal especially for mining and smelting as well as glass production. In this case study from a site in the upper Erzgebirge region (Ore Mountains), results from archeological, geophysical, pedo-sedimentological, geochemical, anthracological, and palynological analyses have been closely linked to allow for a diachronic reconstruction of changing land use and varying intensities of human impact with a special focus on the fourteenth to the twentieth century. While human presence during the thirteenth century can only be assumed from archeological material, the establishment of glass kilns together with quartz mining shafts during the fourteenth century has left behind more prominent traces in the landscape. However, although glass production is generally assumed to have caused intensive deforestation, the impact on this site appears rather weak compared to the sixteenth century onwards, when charcoal production, probably associated with emerging mining activities in the region, became important. Local deforestation and soil erosion has been associated mainly with this later phase of charcoal production and may indicate that the human impact of glass production is sometimes overestimated.
... The deeper groundwater in the crystalline basement of the Black forest has previously been studied (Stober and Bucher, 1999;Stober, 1996), as has been the snowmelt stream water (Feger and Brahmer, 1986) and impact of soils on water chemistry (Feger et al., 1990). Forest influence on surface water chemistry and water yield (Brown et al., 2005), acid precipitation (Probst et al., 1987) and its mitigation by forest liming have been the focus of many publications (Armbruster et al., 2000(Armbruster et al., , 2003Feger et al., 1995;. Quadflieg (1990) studied the influence of forest, soil type, snowmelt water and amount of precipitation on spring water chemistry in a forested mountainous study area in the Bunter Sandstone formation in Hesse. ...
Spring water chemistry is influenced by many factors, including geology, climate, vegetation and land use, which determine groundwater residence times and water–rock interaction. Changes in water chemistry can have a profound impact on their associated ecosystems. To protect these ecosystems and to evaluate possible changes, knowledge of the underlying processes and dynamics is important. We collected water samples at 20 locations during 5 campaigns within the water catchment area of the upper Schönmünz river in the Black Forest National Park, Southwest Germany and analyzed them hydro-chemically for their contents of inorganic constituents, organic carbon content, fluorescence properties as well as several physico chemical field parameters and spring discharge. Results show that water chemistry is strongly dependent on geology and that the response of dissolved organic carbon to changes in hydraulic conditions is highly dynamic. Due to increased flow through the upper soil layer during and after rain events, more organic carbon is extracted from the soil and transported with the water. Fluorescence EEM measurements indicate an allochthonous source of this organic carbon. This study can be used as baseline to assess future changes and serve as a supplement to ongoing studies of the spring ecosystems.
... From autumn 1999 to spring 2000, in both reservoirs, a new annual nitrate cycling pattern was established which is more or less stable over the complete following period up to 2014. This change at the end of the 1990s is part of a general system change, which has been described in a multitude of studies over the whole northern hemisphere under the influence of system response on easing acid pollution conditions (Armbruster et al. 2003;Oulehle et al. 2013;Stoddard et al. 1999). Oulehle et al. (2008) found an improved activity of heterotrophic microbes in the forested catchments as the driving force for decreasing nitrate concentrations in catchment runoff. ...
Arsenic concentrations in a drinking water reservoir system in the Eastern Ore mountains (Osterzgebirge, Germany) were observed over a 17-year period. The region experienced an environmental change during the past 20 years with decreasing acid, sulphur and nitrogen deposition and a recovering vitality of forested catchment sites. An increase of the arsenic content in the reservoir waters during that change was observed. This was caused by a diminished nitrate supply leading to lower redox potential in the sediments favouring sediment arsenic release. The recent annual cycle in the Altenberg reservoir water arsenic concentration was found to be independent from artificial aeration of the hypoxic hypolimnion during the summer stratification. However, we found a strong seasonal dependent change in water As concentration, with a maximum in autumn and a minimum in spring. The low productive system is driven by peat derived organic matter. For the recent arsenic catchment yield coherencies to dissolved organic carbon export and runoff intensity were found, indicating rising arsenic loads due to climate-related soil organic matter destabilization. Thus, in the reservoir system, both dry and wet climate conditions can increase the water As concentrations due to an internal arsenic release and a catchment arsenic import.
... Meeting this need is hampered by the high cost and labor requirements associated with dense sampling of an area of representative size, both at the surface and at depth, and the subsequent analysis of a series of biogeochemical parameters. Many studies have investigated spatial variability in soil biogeochemical properties (Armbruster et al., 2003;Garten et al., 2007;Johnson et al., 2007;Lawrence et al., 2013;Lin et al., 2005;Ulén and Snäll, 1998), but these datasets typically focus on selected properties and lack information on water and thus nutrient fluxes. Comprehensive datasets that consider both hydrological and biogeochemical processes are available for some long-term ecological research sites, such as the Hubbard Brook experimental catchment (e.g., Cho et al., 2010;Groffman et al., 2006Groffman et al., , 2009b and Andrews Experimental Forest (e.g., Anderson et al., 2005;Griffiths, 2013;Johnson and Fredriksen, 2016), albeit with a lower spatial resolution. ...
Current understanding of the variability in soil properties and their relationship to processes and spatial patterns in forested landscapes is limited due to the scarcity of datasets providing such information. Here we present a spatially highly resolved dataset ( http://teodoor.icg.kfa‐juelich.de/ibg3searchportal2/dispatch?metadata.detail.view.id=e3886301‐7252‐4142‐b1a4‐333dfe7f1ca4 ) that provides detailed information on the three‐dimensional variability of biogeochemical properties in the Wüstebach catchment (western Germany), a long‐term environmental observation site of the TERENO (Terrestrial Environmental Observatories) project. High‐resolution soil sampling was conducted, and physical and biogeochemical soil parameters were recorded per horizon. The dataset is helpful in the analysis of the spatial heterogeneity in biogeochemical properties within soil horizons and with depth through the soil profile. In addition, it shows links between hydrological and biogeochemical properties and processes within the system. Overall, the dataset provides a high‐resolution view into (re)cycling, leaching, and storage of nutrients on the catchment scale in a forested headwater catchment.
Core Ideas
A dataset with 3‐D views of biogeochemical soil parameters in a forested headwater catchment is described.
Dataset provides information on spatial heterogeneity and vertical distribution of nutrients.
Transdisciplinary approach: soil chemistry, soil physics, and long‐term monitoring data.
... Although sulphate emissions have declined in Europe, they continue to rise globally (Bouwman et al., 2002), particularly in Asia Matsubara et al., 2009;Wei and Wang, 2005). Nitrate emissions have become relatively more important and there is evidence that nitrate saturation of vegetation and soils may lead to reacidification of some areas (UKAWMN 2001;Armbruster et al., 2003). Overall, acidification is still regarded as the foremost problem affecting biodiversity in surface waters of Northern Europe (Johnson and Angeler, 2010). ...
Many aquatic ecosystems continue to show the impact of acidification. Two factors that have been put forward to explain retarded biological recovery from aquatic acidification: geology and land-use (specifically, coniferous afforestation). The present study tests the hypothesis that afforestation is more significant than underlying geology in limiting recovery. Six streams were sampled using a 2 × 3 design with two types of underlying geology and three levels of afforestation. Results provide evidence for substantial chemical recovery but limited and uneven biological recovery. Statistical analysis suggested that both afforestation and geology had significant impacts on biological indicators, but geology had a greater impact on the richness of acid sensitive species. These results are discussed in relation to competing theories on factors underlying differential and retarded biological recovery.
... The delay in recovery has been attributed to a number of processes related to deposition such as reductions in base cations (Oulehle et al. 2006;Verstraeten et al. 2012), continued acidic deposition in excess of buffering capacity (Alewell et al. 2000;Watmough et al. 2005), and chronic elevated N deposition (Rothe et al. 2002;Boxman et al. 2008). In other instances the recovery is moderated by soil processes e.g., release of previously adsorbed SO 4 2- (Prechtel et al. 2001;Armbruster et al. 2003;Hughes et al. 2012) or the increased production of organic acids . In Atlantic coastal areas, marine inputs (sodium [Na ? ...
Long-term trends in ion concentrations of bulk precipitation, throughfall, forest floor leachate (humus water) and shallow and deep soil water were assessed at two Sitka spruce (Picea sitchensis) stands—one on an Atlantic peat bog in the west of Ireland (Cloosh), the other on the east coast on a peaty podzol (Roundwood). Deposition at Cloosh was dominated by marine ions (sodium, [Na+], chloride [Cl−], and magnesium [Mg2+]), whereas bulk precipitation and throughfall at Roundwood was characterized by inputs of non-marine sulphate (nmSO4 2−), acidity and inorganic nitrogen (NH4 +, NO3 −). Significant declines in concentrations of nmSO4 2− and acidity in bulk precipitation and throughfall were observed at both sites. The decline in throughfall nmSO4 2− was significantly related to reductions in European sulphur dioxide (SO2) emissions. At Roundwood, SO4 2− declined significantly in humus, shallow and deep soil water. In deep soil water this was accompanied by a long-term increase in pH and a reduction in total aluminum (Altot). The recovery from acidification was delayed by high concentrations of NO3 −, which strongly influenced acidity and Altot concentrations. At Cloosh, there was a significant decline in SO4 2− in humus water but long-term trends were not evident in shallow or deep soil water; SO4 2− concentrations at these depths fluctuated in response to drought-events. Marine ions strongly influenced soil water chemistry at both sites; at Cloosh soil water acidity was strongly related to Na+ and Cl−, while at Roundwood, Na+, Cl− and Mg2+ influenced Altot concentrations. Dissolved organic carbon increased significantly in humus and soil water at Roundwood, where it was associated with declining acidity. Soil water at both sites was influenced by a combination of anthropogenic sulphur (S) and nitrogen (N) deposition, drought and sea-salt events. The study highlights the value of long-term monitoring in assessing the response of forest soils to S and N deposition against a background of climate influences on soil water through drought and sea-salt events.
... Acid deposition has been an important and increasing cause of soil acidification in Europe since the industrial revolution and, recently with the development of intensive livestock production and the resultant large emissions of ammonia. The acidification induced by acidic compounds produced by industrial activities has been widely investigated on natural and forested silicate catchments (Armbruster et al., 2003; Fernandez, 1985; Fernandez et al., 2003; Likens et al., 1998; Stoddard et al., 1999 ). Ammonium-based fertilizers have dramatic consequences on metal mobilization and plant uptake (Goulding and Blake, 1998) and represent the single most significant cause of soil acidification on most agricultural land (Ganev, 1992; Graham et al., 2002). ...
In natural river systems, the chemical and isotopic composition of stream- and ground waters are mainly controlled by the geology and water-rock interactions. The leaching of major cations from soils has been recognized as a possible consequence of acidic deposition from atmosphere for over 30 years. Moreover, in agricultural areas, the application of physiological acid fertilizers and nitrogen fertilizers in the ammonia form may enhance the cation leaching through the soil profile into ground- and surface waters. This origin of leached cations has been Studied on two small and adjacent agricultural catchments in Brittany, western France. The study catchments are drained by two first-order streams, and mainly covered with cambisoils, issued from the alteration and weathering of a granodiorite basement. Precipitations, soil water- and NH(4) acetate-leachates, separated minerals, and stream waters have been investigated. Chemical element ratios, such as Ba/Sr, Na/Sr and Ca/Sr ratios, as well as Sr isotopic ratios are used to constrain the relative contribution from potential Sources of stream water elements.
... In some regions, the contribution of anthropogenic acids to ANC loss at peak flow has decreased over recent decades and the area affected by acid spring floods has declined (Laudon & Bishop, 2002). In other locations, episodes driven by strong acid anions still reduce pH and increase metal concentrations, particularly where soil base cations have been depleted (Campbell & Eagar, 2002;Lawrence, 2002;Armbruster, Abiy & Feger, 2003;Lepori et al., 2003b;Laudon et al., 2004a,b;Wellington & Driscoll, 2004). A priority in acidification research is to link more closely this quantitative hydrochemical understanding about the current character of episodes with better evidence -rather than inference -about biological consequences. ...
1. Although mean pH is increasing in acidified streams throughout Europe, benthic invertebrates are recovering only slowly. One developing hypothesis is that acid episodes continue to restrict recolonisation and recovery. Here, we used intra‐annual sampling in replicate circumneutral, acid and episodic streams at the Llyn Brianne experimental catchments to assess possible mayfly exposure to episodic effects quantified from a risk index based on long‐term discharge. Episodic effects were then tested using short‐term transplantations of animals in enclosures.
2. No mayflies occurred in acid streams while Baetis rhodani occurred in episodic streams but declined to zero density following low pH in autumn. Ephemerella ignita , Baetis vernus , B. muticus , Rhithrogena semicolorata , Ecdyonurus spp. and Heptagenia lateralis occurred only in the circumneutral streams. The first two species were present as nymphs only during July and August so that episodic exposure risk was minimal, but the remaining species occurred as nymphs in all months.
3. Baetis rhodani transplanted during base‐flow (September 2003) and high‐flow (April 2004) were exposed to either; (i) continual (chronic) exposure in the acid streams over 16 days or (ii) repeated short‐term (episodic) exposure to acid conditions for 2 × 4 day periods interspersed with 4‐day recovery periods in the circumneutral streams. Baetis survival in the circumneutral streams (always pH > 5.7) remained high during both low‐ and high‐flow. By comparison, mortality increased ( P < 0.01) during chronic and episodic exposure, but only during high‐flow (mean pH 3.8–3.9, cf. 5.5–5.8 at low flow) when mortality varied significantly in the order chronic (>80%) > episodic (>40%) >circumneutral (<10%).
4. We conclude that, despite Europe‐wide trends towards chemical recovery from acidification, even short exposures to high‐flow events at Llyn Brianne are still sufficiently acid to reduce the survival of B. rhodani . Most mayfly species absent from acid and episodic streams have life cycles that would increase acid exposure risks during autumn and winter, and this may be sufficient to explain their current distribution.
... To investigate the response of forest ecosystems in relation to increasing/decreasing nitrogen and sulfur deposition, analyses of dissolved inorganic nitrogen (DIN D NO 3 C NH 4 C ) and sulfate (SO 4 2 ) budgets in small watersheds have been widely used (Likens and Borman, 1995;Castro and Morgan, 2000;Armbruster et al., 2003;Ohte, 2007). To make an appropriate evaluation in a forested site, the total (wet C dry) deposition of DIN and SO 4 2 should be measured (Likens and Borman, 1995;Chiwa et al., 2003). ...
To investigate the effects of storm flow samplings on the evaluation of DIN and SO42− budgets, we conducted storm flow samplings and discrete interval (weekly) samplings of stream water, throughfall, and stemflow. This investigation lasted for three years and took place in a small forested watershed in western Japan. Annual exports were calculated by the sum of the load (ΣLtotal)- sum of the discharge (ΣQtotal) relationships obtained by storm flow samplings. These were then compared to calculated ones that were based on LQ relationships obtained by discrete interval sampling. The results of discrete interval sampling showed that the relationships of DIN or SO42− concentration to the discharge amount found in stream water differed from those of storm flow sampling. This was especially notable in years with higher annual precipitation and subsequent higher annual discharges. Also, exports of DIN and SO42− during storm flow periods accounted for 83% and 78% of annual exports on 3-year averages, respectively. These results confirmed that storm flow samplings are essential for estimating annual exports of DIN and SO42−. Annual exports that were calculated based on just discrete interval sampling (46% and 17%, respectively) overestimated DIN and SO42− from discrete interval and storm flow samplings on a 3-year average. These overestimates were pronounced in years of higher discharge, and critically affected the rates of net-retention or export of DIN and SO42−. The relationship of smaller input than output of DIN was reversed if storm flow sampling was included. Copyright © 2009 John Wiley & Sons, Ltd.
... Data quantifying the regional frequency of streams still affected by acidic episodes are uncommon. Episodes nevertheless occur often enough across Europe (Raddum et al., 2001;Armbruster et al., 2003;Lepori et al., 2003a) and North America (Clair et al., 2001;Campbell & Eagar, 2002;Lawrence, 2002) to be considered important in what are otherwise recovering locations (Stoddard et al., 1999;Evans et al., 2001;Skjelkvåle et al., 2003). Our data show that such effects are strongest where there are continuing additions of strong acids to base-poor run-off. ...
We tested two predictions required to support the hypothesis that anthropogenic acidic episodes might explain the poor biological response of upland British streams otherwise recovering from acidification: (i) that invertebrate assemblages should differ between episodic and well-buffered streams and (ii) these effects should differentiate between sites with episodes caused by anthropogenic acidification as opposed to base-cation dilution or sea-salt deposition. Chronic and episodically acidic streams were widespread, and episodes reflected acid titration more than dilution. Nonmarine sulphate (16–18% vs. 5–9%), and nitrate (4–6% vs. 1–2%) contributed more to anion loading during episodes in Wales than Scotland, and Welsh streams also had a larger proportion of total stream sulphate from nonmarine sources (64–66% vs. 35–46%). Sea-salts were rarely a major cause of episodic ANC or pH reduction during the events sampled. By contrast, streams with episodes driven by strong anthropogenic acids had lower pH (5.0±0.6) and more dissolved aluminium (288±271 μg L−1) during events than where episodes were caused by dilution (pH 5.4±0.6; 116±110 μg Al L−1) or where streams remained circumneutral (pH 6.7±1.0; 50±45 μg Al L−1). Both biological predictions were supported: invertebrate assemblages differed among sites with different episode chemistry while several acid-sensitive species were absent only where episodes reflected anthropogenic acidification. We conclude that strong acid anions – dominantly nonmarine sulphate – still cause significant episodic acidification in acid-sensitive areas of Britain and may be a sufficient explanation for slow biological recovery in many locations.
... Acidification of soils, surface water and groundwater is still of major concern in silicate ecosystems, despite a significant reduction in acid deposition (H + , S-compounds) in the last 20 a (Likens et al., 1998; Stoddard et al., 1999; Ale well et al., 2000; Busch et al., 2001; Armbruster et al., 2003; Matzner et al., 2004). Deep groundwater is usually less acidic than surface water (Neal et al., 1990a,b; Davies et al., 1992) due to release of base cations via weathering. ...
The role of different minerals in base cation release and thus the increase of buffering capacity of groundwater against acid deposition is controversially discussed in the literature. The ⁸⁷Sr/⁸⁶Sr ratios and base cation concentration were investigated in whole rock leachates, mineral separates, precipitation, soil solution, groundwater and stream water samples in the Lehstenbach catchment (Germany) to identify the weathering sequence of the granite bedrock. Three different approaches were followed in parallel. It was assumed that the contribution of different minerals to base cation supply of the groundwater with increasing weathering intensity would be observed by investigating (1) unweathered rock leachates, deep groundwater and shallow groundwater, (2) groundwater samples from new groundwater wells, reflecting the initial weathering of the drilled bedrock, and groundwater from wells that were drilled in 1988, (3) stream water during baseflow, dominated by deep groundwater, and stream water during high flow, being predominantly shallow groundwater. Whereas the first approach yielded consistent patterns, there was some evidence that groundwater from the new wells initially reflected contamination by the filter gravel rather than cation release in an initial stage of weathering. Time series samples of stream water and groundwater solute concentrations and isotope ratios turned out to reflect varying fractions of soil water and precipitation water at baseflow and high flow conditions rather than varying contributions of different minerals that prevail at different stages of granite weathering.
... [3] In spite of the high levels of N deposition in Japan, N budgets in Japanese forested watersheds have not been fully evaluated [Ohrui and Mitchell, 1997; Baba et al., 2001; Mitchell et al., 1997; Ohte et al., 2001b; Wakamatsu et al., 2001; Tokuchi et al., 2004]. Analysis of the input‐output N budget for a small watershed provides insight into the response of forest ecosystems to N deposition [Armbruster et al., 2003; Campbell et al., 2004; Likens and Bormann, 1995]. On the other hand, considerable research on N budgets in forested watersheds has been conducted [Dow and DeWalle, 1997; Kahl et al., 1999] and summarized for North America [Johnson and Lindberg, 1992; Campbell et al., 2004] and Europe [Dise and Wright, 1995; Bredemeier et al., 1998]. ...
1] To evaluate the role of stormflow in reducing N retention in forested watersheds, we investigated the inorganic N budget of a Japanese suburban forested watershed for 4 years where the proportion of direct flow to precipitation is considerably high (mean is 33%; range is 25–42%). Soil net N mineralization and net nitrification were also measured at middle and lower positions of a slope within the watershed to evaluate nitrate (NO 3 −) pool size. Annual mean N deposition via throughfall plus stemflow was 15.5 kg N ha −1 yr −1 (13.6–17.1 kg N ha −1 yr −1), which exceeded the threshold value to potentially induce N leaching from forested watersheds. Net nitrification at the middle position was comparable with the lower position. This suggests that the NO 3 − rich area is large, which could be partly caused by comparable soil moisture conditions with the lower position due to rising groundwater levels during storm events. Annual mean N export was 10.4 kg N ha −1 yr −1 (7.8–12.5 kg N ha −1 yr −1), and subsequent N retention was distinctly low 33% (12–53%). Stormflow accounted for more than 80% of total annual N export. Furthermore, N retention was lower (12 and 27%) in years with higher proportions of direct flow than in years with lower proportions (36 and 53%). Therefore, stormflow is a significant factor in reducing N retention in forested watersheds. The effect of stormflow observation on the comparison of N budgets in other watersheds with different climate and/or hydrologic conditions is discussed.
... Moldan, unpublished data, 2004]. Since 1987, i.e., in less than 20 years, industry restructuring and installation of scrubbers in power plants have reduced industrial S emission rates by more than 90% [Dostalova et al., 2004]; by comparison, elsewhere in Europe and Northern America, industrial emission rates have decreased by 40 to 60% over the past 30 years [Ambuster et al., 2003;Likens et al., 2002;Eimers and Dillon, 2002;Moldan et al., 2004]. In addition to the temporal gradient of easing pollution, a sizable geographical S pollution gradient has been reported in Central Europe [Fottova, 2003]. ...
1] Sulfur isotope systematics were studied in 13 small catchments in the Czech Republic, similar in topography (V-shaped valley) and vegetation (Norway spruce). The sites differed in elevation, rainfall, bedrock, soil type and S pollution. Across the sites, d 34 S values decreased in the order: bulk deposition > runoff > spruce throughfall > C-horizon soil > A/B-horizon soil > O-horizon soil > bedrock (means of 5.5, 4.8, 4.7, 4.6, 4.2, 3.1 and 1.5%, respectively). Some of the sites had a net export of S, while others accumulated S. Sites exporting S were located in the polluted north where atmospheric S input started to decrease in 1987. Sites retaining S were located in the relatively unpolluted south. Sulfur isotope composition of runoff depended on whether the catchment accumulated or released S. Sites releasing S had runoff d 34 S values lower than deposition. In contrast, sites retaining S had runoff d 34 S values higher than deposition. Across the sites, the d 34 S values of runoff were not correlated with d 34 S values of bedrock, indicating that the contribution of bedrock to S in runoff was negligible. The d 34 S values of runoff were strongly positively correlated with the d 34 S values of soil. Sulfur present in the C-horizon of soils was mainly derived from atmospheric deposition, not bedrock. Sulfur isotope mass balances were constructed for each catchment, making it possible to quantify the difference between d 34 S values of the within-catchment source/sink of S and runoff S. Sulfur isotope mass balances indicated that the sink for the retained S at unpolluted sites and the source of the released S at polluted sites were isotopically fractionated by the same amount relative to runoff S. Inorganic and organic processes were considered as possible causes for this observation. Biological S cycling involves a variety of reactions, some of which fractionate S isotopes. In contrast, adsorption/desorption of inorganic sulfate in soil and weathering of S-containing minerals do not fractionate S isotopes. Therefore the within-catchment source/sink of S must be largely a result of biological S cycling. Organic S cycling played an important role over a wide range of atmospheric S inputs from 13 to 130 kg S ha À1 yr À1 . ska (2005), Isotopic evidence for processes of sulfur retention/release in 13 forested catchments spanning a strong pollution gradient (Czech Republic, central Europe), Global Biogeochem. Cycles, 19, GB4012, doi:10.1029/2004GB002396.
... acid deposition) soils may have accumulated considerable amounts of elements which be released under modified environmental and management conditions. Armbruster et al. (2003) gave an example for such a memory effect (S accumulation) for forested catchments in the Eastern Ore Mountains (Saxony, Eastern Germany) which received extremely high S deposition during the period 1960 until 1990. Hence, forest management must consider the element pools in the soil and their potential mobilization. ...
Scaling of forest and water relations are mostly concerned with two diverse dimensions resulting from trade-off in various
environmental and regional conditions. On one side, scaling is used to develop best forest management practice with the aim
of reducing runoff and providing good quality water. In conditions of water scarcity, scaling is mostly concerned with the
protection of the forest cover which provides other beneficiary goods and services such as timber, biodiversity and carbon
sequestration. Forests significantly influence the hydrological cycle, mostly in a beneficiary way: forests, due to higher
infiltration rates and soil water consumption induce lower stormflows and greater soil stability than any other vegetation
type, forest soils also purify water. On the contrary, in arid and semi-arid conditions, the effects of forests on hydrology
can be unfavorable because forests as major water consumers contribute to water supply deficiency. Global warming claims better
utilization of forest hydrological goods and services and new approaches on adaptive forest management as a result of climate
change. Climate change also generates new scaling challenges of forest and water interactions.
... Both catchments have comparable areas (9.4-11 ha) and are drained by perennial first-order streams. Schluchsee is underlain by a basepoor granite, whereas the bedrock of the Rotherdbach catchment consists of rhyolite with a mineral composition comparable to Schluchsee (Armbruster et al., 2003). In both catchment podzolic soil types prevail. ...
Water-plant relations play a key role in the water cycling in terrestrial ecosystems. Consequently, changes in tree species
composition may have distinct effects on the water retention capacity as well as on the pattern of streamflow generation.
Such changes may result from modified interception properties and transpiration related to differences in canopy properties
and root distribution. In order to evaluate the potential hydrological effects of the current silvicultural conversion from
monocultural conifer stands into mixed or pure deciduous stands the hydrological model BROOK90 was applied to two forested upland catchments in Germany. The Rotherdbach catchment (9.4ha, 93yr-old Norway spruce) is
situated in the Eastern Ore Mountains. The Schluchsee catchment (11ha, 55-yr-old Norway spruce) is located in the higher
altitudes of the Black Forest. The calibrated model is capable to describe rather well the temporal variation of streamflow
but also the portions of the individual flow components. Data for a beech scenario were adapted for each site using a standard
parameter set for deciduous trees provided by BROOK90. The annual discharge in the fictional beech stand at Rotherdbach is 30 to 50% higher compared to spruce with an increase
of soil moisture and especially the slow streamflow components. This mainly results from low interception rates during winter
time. In contrast, the spruce stand has a permanently higher interception rate. Effects of tree species conversion are moderate
at Schluchsee. The annual discharge of a fictional beech stand at Schluchsee is 7 to 14% higher compared to spruce. There
in contrast to Rotherdbach, effects of tree species conversion on soil moisture dynamics are small since vertical percolation
in the highly permeable soil dominates and precipitation is abundant. Practical forestry will favorably establish mixed beech–spruce
rather than pure beech stands. However, it is critical to simulate mixed stands with BROOK90. Therefore, a simple summation of model results from spruce and beech according to their respective area in a fictional mixed
stand can only be a first approximation. Advanced hydrological simulation of mixed stand conditions should regard interactions
of tree species and spatial parameter distribution. However, this is not yet feasible due to a distinct lack of information.
As a consequence, there is a strong need to collect relevant hydrological and ecophysiological data in mixed stands in the
future.
... Many investigators have focused on the role of different lithologies [10,11], different levels of acid deposition [12], and the influence of tree species [13,14] on the biogeochemistry of forest ecosystems. Tree species may greatly influence the biogeochemistry of forest ecosystems [15]. ...
The effect of European beech (Fagus sylvatica) and Norway spruce (Picea abies) on acid deposition and soil water chemistry was studied at a site in the Ore Mts., Czech Republic, that has been subjected to decades of elevated acidic deposition. Dry deposition onto the spruce canopy significantly increased acid input to the soil in comparison to the beech canopy. As a result soil waters were more acidic; Al, SO4(2-), and NO3- concentrations were significantly higher; and Ca and K concentrations were lower in the spruce stand than in the beech stand. The concentrations of potentially toxic inorganic aluminium (Al(in)) were, on average, three times higher in the spruce stand than in the beech stand. Thus, Al played a major role in neutralizing acid inputs to mineral soils in the spruce stand. Despite the higher dissolved organic carbon (DOC) concentrations in spruce organic soil solutions, organic Al (Al(org)) accounted for only 30% of total Al (Al(tot)), whereas in beech organic soil solutions Al(org) was 60% of Al(tot). Soil waters in the beech stand exhibited Al(in) concentrations close to solubility with jurbanite (Al(SO4)OH.5H2O). The more acidic soil waters in the spruce stand were oversaturated with respect to jurbanite. The Bc/Al(in) ratio (Bc = Ca + Mg + K) in O horizon leachate was 4.6 and 70 in spruce and beech stands, respectively. In beech mineral soil solutions, the Bc/Al(in) ratio declined significantly to about 2. In the spruce stand, mineral soil solutions had Bc/Al(in) values below the critical value of 1. The observed Bc/Al(in) value of 0.4 at 30 cm depth in the spruce stand suggests significant stress for spruce rooting systems. A more favourable value of 31 was observed for the same depth in the beech stand. The efficiency of the spruce canopy in capturing acidic aerosols, particulates, and cloud water has resulted in the long-term degradation of underlying soils as a medium for sustainable forest growth.
Bibliographie der im Zeitraum von 2011 – 2015 erschienenen Veröffentlichungen zu geowissenschaftlichen Problemen des sächsischen Territoriums.
German Bibliography for the period from 2011 – 2015 with published publications to geoscientific topics of the Saxon territory (Saxony in Germany).
The essential constituent elements of land plants and animals move in biogeochemical cycles that begin with the uptake of nutrients from the soil, extending through allocations to plant biomass, especially photosynthetic tissues, and nutrient return to the soil in plant detritus. Decomposition of dead plant materials releases these nutrient elements for reuse or potential loss to stream waters. At any given time, this internal cycle of elements dwarfs the new sources of nutrients to the ecosystem from the atmosphere or rock weathering. Essential elements are strongly conserved within ecosystems, whereas nonessential or nonlimiting elements are potentially lost to stream water. For nitrogen, microbial transformations among forms in the soil result in small losses of nitrogen trace gases to the atmosphere. Animals influence the movement of materials within terrestrial ecosystems, and periodic fires result in large losses of nutrients. Human activities, resulting in acid rain, excess nitrogen deposition, rising CO2, and global warming, have all altered the cycle of essential elements in terrestrial ecosystems.
From a biogeochemical perspective, catchments can be regarded as reactors that transform the input of various substances via precipitation, deposition, or human activities as they pass through soils and aquifers towards receiving streams. Understanding and modeling the variability of solute concentration in catchment waters require the identification of prevailing processes, determining their respective contributions to the observed transformation of substances, their interplay with hydrological processes, and the determination of anthropogenic impacts. However, numerous biogeochemical processes often interact in a highly non-linear way and vary on temporal and spatial scales, resulting in temporally and spatially varying water chemistry in catchments. This is particularly true for riparian wetlands. Processes in this catchment area often superimpose the influence of the hill slope (and largest) area of the catchment on surface water quality. Accordingly, the first part of this thesis (Study 1 and 2), focuses on the temporal and spatial variability of biogeochemical processes at the catchment scale. Therefore, the first aim was to identify the prevailing biogeochemical processes which affect the quality of catchment waters in two forested granitic catchments. Based on these results, (i) the long-term behavior of these processes was determined (Study 1) and (ii) hot spots of these processes at the catchment scale along different flow paths were identified (Study 2). The second part (Study 3) focuses on the interplay between hydrological and biogeochemical processes in a riparian wetland, with the aim of systematically tracing back the temporal patterns of stream water chemistry to different biogeochemical processes and antecedent hydrological boundary conditions in the wetland. The third part (Study 4 and 5) focuses on weathering processes with the goal (i) of identifying the mineralogical sources of the groundwater’s buffer capacity against acid atmospheric deposition in a forested granitic catchment and (ii) determining the mineralogical sources of the high cation loads in surface water, induced by intensive agricultural activities in two agricultural granitic catchments. To reach these aims, multivariate statistical methods of dimensionality reduction (linear Principal Component Analysis, non-linear Isometric Feature Mapping), a low-pass filtering of time-series, a Cluster analysis, and major and trace element ratios and strontium isotopes were used. A small number of biogeochemical process bundles explained 94% and 89% of the variance of the data set in Study 1 and 2, respectively. In Study 1, redox and topsoil processes, road salt and sulfate contamination were identified as predominating processes influencing water chemistry in the respective catchments. Low-pass filtered time series of component scores revealed a different long-term behavior at different sampling sites in both catchments, which could be traced back to the fraction of wetland area in the respective subcatchments as well as by the varying thickness of the regolith. Study 2 revealed that the upper 1 m topsoil layer could be considered as a biogeochemical hot spot for redox processes, acid-induced podsolization, and weathering processes along different flow paths. Up to 97% of the biogeochemical transformation of the chemical composition of soil solution, groundwater and stream water in the Lehstenbach catchment was restricted to this soil layer representing less than 2% of the catchment’s regolith. Wetland stream water, mobilized in the topsoil layer being considered a biogeochemical hot spot, showed a highly dynamic temporal pattern of component scores. Study 3 revealed four different types of wetland stream water chemical status, depending on the interplay between discharge dynamics, biological activity, and the water table position in the wetland. The sequence of different stream water types roughly followed a seasonal pattern, albeit being heavily modified by the respective hydrological boundary conditions for different years. Extended periods of low groundwater level in the second half of the growing season drastically changed the chemical boundary conditions, becoming evident in a drastic reoxidation of reduced species like sulfides and corresponding effects. Weathering processes are one of the predominating biogeochemical process bundles influencing water chemistry in forested catchments. Study 4 showed that the mineralogical sources of the groundwater’s buffer capacity against acid atmospheric deposition were dominated by the release of base cations from apatite dissolution, preferential cation release from feldspars and biotite, and feldspars weathering. In Study 5, determining the mineralogical sources of the high cation loads in surface water induced by intensive agricultural activities revealed a dominant manure contribution in the topsoil, and enhanced mineral dissolution (plagioclase and biotite) by fertilizer application in subsoils, becoming the unique source of base cations in the saprolite. Stream water chemistry differed from that of soil water, suggesting that stream water chemistry was dominated by elements issued from enhanced mineral and rock weathering. Soil acidification induced by agriculture allows the mobilization of cations stored in soil layers, enhances the rock weathering and accelerates plagioclase dissolution, which can highly influence stream water quality. Numerous biogeochemical, hydrological, and anthropogenic processes were found to interact with each other, mostly with non-linear patterns, influencing catchment water chemistry. The integral approach used in this thesis would be a useful prerequisite to develop accurate and parsimonious models commonly used for water management purposes by distinguishing between short- term and long-term shifts, reducing the number of processes to the predominating ones ultimately to be included in the model, focusing on hot spots and including spatial patterns where necessary and appropriate.
We evaluated the nutrient input via incident rainfall in a Eucalyptus dunnii stand in the Brazilian Pampa biome. During the two-year study, we analyzed nutrient concentrations in incident rainfall (P), throughfall via drip (Pi), and stemflow (Et). Ion concentrations (NO2-, NO3-, PO43-, SO42-, Cl-, K+, Ca2+, and Mg2+) were determined from the aqueous solution, and based on the water volume, the quantity per hectare (kg ha-1) was estimated for each element. Statistical differences observed by ANOVA and separation of means contrasts were subjected to Tukey’s test (5%), adopting a completely randomized design. Higher concentrations of SO42- in P; NO3- in Pi solution, and K+, Ca2+, Mg2+, and Cl- in Et were observed. Greater amounts of nutrients such as Cl-, K+, Ca2+, and SO42 were incorporated via Pi.
1. A current need in freshwater acidification research is to explain why biological recovery has not matched unequivocal evidence of chemical reversal. A leading hypothesis is that acid-sensitive species are prevented from recolonising recovering streams because of anthropogenic acid episodes - transient periods of reduced pH during rainstorms or snowmelt (hours to weeks).
2. Intra-annual variation in invertebrate abundance and survival during episodes were assessed in episodic streams at the Llyn Brianne experimental catchments. Survival patterns produced clear evidence that acid episodes are still toxic to sensitive species.
3. Using large-scale surveys data from 89 streams spread across Wales and Scotland, I next tested five predictions required to support the ‘episodic acidification’ hypothesis: i) there should be differences in invertebrate composition between episodic and well-buffered streams; ii) any such effects should differentiate sites where episodes are driven by anthropogenic acidification as opposed to base-cation dilution; iii) chemical variation between base- and storm-flow should be greater in regions receiving the most acid
deposition (Wales and Galloway > the NW Highlands); iv) strong variations in invertebrate assemblages should result and v) they should reflect storm-flow (i.e. episode) chemistry more than base-flow.
4. Strong acid anions -dominantly non-marine sulphate - still contribute to episodic acidification in sensitive areas. pH fell during storm-flow by 0.5-1.8 units in acid and episodic sites everywhere. However, aluminium concentrations were significantly greater, or increased more between flows, in Galloway and Wales than in the NW Highlands. Loss of ANC at acid or episodic sites was greatest in Galloway whereas mean values became
negative only in Wales. Variations in invertebrate assemblages between acid, episodic and circumneutral streams were most marked in Wales and Galloway and effects were greatest in streams with episodes driven largely by non-marine sulphate. Although these patterns reflected both base-flow and storm-flow chemistry, correlations between assemblage structure and aluminium were strongest at storm-flow.
5. Regression models were used to project the effects of base-flow or storm-flow pH on invertebrates using trends apparent across the UK Acid Waters Monitoring Network (UKAWMN). Episode chemistry provided the best predictions of acidification effects on stream invertebrates, but model projections were affected by critical assumptions about future recovery process.
6. These data illustrate that acid episodes still affect stream organisms in spite of continued recovery in air and water quality and this may be a sufficient explanation for slow biological recovery in many locations. Episodic effects may impose important controls on organisms as recovering sites reach the base-flow pH range 5.5-7. The strongest recommendation is for better understanding and monitoring of the hydrochemistry and biological effects of acid episodes as acid deposition abates.
Published by the American Geophysical Union as part of the Water Resources Monograph Series, Volume 19. What are the forms and processes characteristic of mountain rivers and how do we know them? Mountain Rivers Revisited, an expanded and updated version of the earlier volume Mountain Rivers, answers these questions and more. Here is the only comprehensive synthesis of current knowledge about mountain rivers available. While continuing to focus on physical process and form in mountain rivers, the text also addresses the influences of tectonics, climate, and land use on rivers, as well as water chemistry, hyporheic exchange, and riparian and aquatic ecology. With its numerous illustrations and references, hydrologists, geomorphologists, civil and environmental engineers, ecologists, resource planners, and their students will find this book an essential resource. Ellen Wohl received her Ph.D. in geology in 1988 from the University of Arizona. Since then, she has worked primarily on mountain and bedrock rivers in diverse environments.
Soil properties determine to a large extent the functioning of terrestrial ecosystems. Changes in soil solution chemistry and element fluxes with soil solution (seepage) are most important for ground and surface water quality, and in relation to the nutrient uptake by roots. Among other factors, the influences of deposition, tree species, soil properties and hydrology on soil solution chemistry and seepage fluxes in forest ecosystems have been addressed in numerous papers in the past. At our sites the changes in atmospheric deposition in the last two decades were significant (Matzner et al., this Vol., Chap. 14). The effects of these changes on soil solution chemistry and seepage fluxes will be addressed in this chapter.
Biogeochemistry-winner of a 2014 Textbook Excellence Award (Texty) from the Text and Academic Authors Association-considers how the basic chemical conditions of the Earth, from atmosphere to soil to seawater, have been and are being affected by the existence of life. Human activities in particular, from the rapid consumption of resources to the destruction of the rainforests and the expansion of smog-covered cities, are leading to rapid changes in the basic chemistry of the Earth. This expansive text pulls together the numerous fields of study encompassed by biogeochemistry to analyze the increasing demands of the growing human population on limited resources and the resulting changes in the planet's chemical makeup. The book helps students extrapolate small-scale examples to the global level, and also discusses the instrumentation being used by NASA and its role in studies of global change. With extensive cross-referencing of chapters, figures and tables, and an interdisciplinary coverage of the topic at hand, this updated edition provides an excellent framework for courses examining global change and environmental chemistry, and is also a useful self-study guide.
Soil water chemistry in forest soils over 20years was studied at nine sites in southern Sweden. The aim was to investigate the recovery from acidification and the influence of strong sea salt episodes that occur in the region. All sites but one showed signs of recovery from acidification along with the reduced sulphur deposition, but the recovery progress was slow and the soil water was in most cases still highly acidic at the end of the period. In several cases the recovery was delayed by episodes of sea salt deposition, leading to transient acidification. The less marked decrease of sulphur concentrations in soil water than of sulphur deposition, highlighted the importance of sulphur adsorption/desorption in the acidification and recovery process. Nitrogen retention capacity was exceeded on one site, leading to nitrate leaching and extremely low pH. Storm fellings on two sites in the end of the period led to effects similar to those of regeneration fellings. It was concluded that the soils in the region are in an early stage of recovery. The future progress of recovery strongly depends on future nitrogen retention of forest soils and the frequency of sea salt episodes.
Acid atmospheric emissions within Europe and North America have decreased strongly since 1985 and most recent acidification studies have focused on the changes occurring within ecosystems as a result of this decreased deposition. This current study documents a soil acidification trend under ambient N deposition conditions over a 13year period, suggesting that acidification continues to be a process of concern at this Calluna vulgaris dominated heathland with an acidic sandy soil. The annual manipulation of climatic conditions on this heathland simulated the predicted summer rainfall reduction (drought) and resulted in a long term retardation of the soil acidification trend. The pH of the soil solution significantly decreased over the course of the trial for both treatments, however, in the final 2years the decline continued only in the Control treatment. This retardation is primarily associated with the reduction in rainfall leading to lower drainage rates, reduced loss of cations and therefore reduced lowering of the soil acid neutralizing capacity (ANC). However, a change in the underlying mechanisms also indicated that N transformations became less important in the Drought treatment. This change corresponded to an increase in groundcover of an air-pollution tolerant moss species and it is hypothesized that this increasing moss cover filtered an increasing quantity of deposited N, thus reducing the N available for transformation. A soil acidification lag time is expected to increase between the two treatments due to the cumulative disparity in cation retention and rates of proton formation. To the authors' knowledge, this is the first study in which such acidification trends have been demonstrated in a field-scale climate manipulation experiment.
Elevated atmospheric inputs of NH4+ and NO3– have caused N saturation of many forest ecosystems in Central Europe, but the fate of deposited N that is not bounded by trees remains largely unknown. It is expected that an increase of NO3– leaching from forest soils may harm the quality of groundwater in many regions. The objective of this study was to analyze the input and output of NH4+ and NO3– at 57 sites with mature forest stands in Germany. These long-term study sites are part of the European Level II program and comprise 17 beech, 14 spruce, 17 pine, and 9 oak stands. The chloride balance method was used to calculate seepage fluxes and inorganic N leaching below the rooting zone for the period from 1996 to 2001. Nitrogen input by throughfall was significantly different among most forest types, and was in the order: spruce > beech/oak > pine. These differences can be largely explained by the amount of precipitation and, thus, it mirrors the regional and climatic distribution of these forest types in Germany. Mean long-term N output with seepage was log-normal distributed, and ranged between 0 and 26.5 kg N ha–1 yr–1, whereby 29 % of the sites released more than 5 kg N ha–1 yr –1. Leaching of inorganic N was only significantly lower in the pine stands (P < 0.05) compared with leaching rates of the spruce stands. Median N output : input ratio ranged between 0.04 and 0.11 for the beech, oak, and pine stands, while the input : output ratio of the spruce stands was 0.24, suggesting a higher risk of NO3– leaching in spruce forests. Following log-transformation of the data, N input explained 38 % of the variance in N output. The stratification of the data by the C : N ratio of the O horizon or the top mineral soil revealed that forests soils with a C : N ratio < 25 released significantly more NO3– (median of 4.6 kg N ha–1 yr–1) than forests with a C : N ratio > 25 (median of 0.8 kg N ha–1 yr–1). The stratification improved the correlation between N input and N output for sites with C : N ratios < 25 (r2 = 0.47) while the correlation for sites with C : N ratios > 25 was weaker (r = 0.21) compared with the complete data set. Our results suggest that NO3– leaching may increase in soils with wide C : N ratios when N deposition remains on a high level and that the potential to store inorganic N decreases with C : N ratios in the O horizons becoming more narrow.
Nitratauswaschung aus Waldböden: eine Analyse von Dauerbeobachtungsflächen in Deutschland
Erhöhte NH4+- und NO3–-Einträge haben zu einer N-Sättigung vieler Wälder in Mitteleuropa geführt. Der Verbleib des deponierten Stickstoffs, der nicht in den Bäumen gebunden ist, ist jedoch weitgehend unbekannt. Es wird angenommen, dass ein Anstieg der NO3–-Auswaschung aus Waldböden die Grundwasserqualität in vielen Regionen gefährdet. In dieser Studie wurden die Eintrags- und Austragsraten von NH4+ und NO3– von 57 Waldflächen in Deutschland analysiert. Diese Dauerbeobachtungsflächen sind Teil des europäischen Level-II-Programms und setzen sich aus 17 Buchen-, 14 Fichten-, 17 Kiefern- und 9 Eichenbeständen zusammen. Die Cl–-Bilanz-Methode wurde angewandt, um die Sickerwassermengen unterhalb des Wurzelraumes für die Periode von 1996 bis 2001 zu berechnen. Die N-Einträge waren in vielen Waldtypen signifikant unterschiedlich und zeigten folgende Ordnung: Fichte > Buche/Eiche > Kiefer. Diese Unterschiede können weitgehend mit der Niederschlagsmenge erklärt werden und spiegeln somit die regionale und klimatische Verteilung dieser Waldtypen in Deutschland wider. Der mittlere, langjährige N-Austrag war log-normal verteilt and variierte zwischen 0 und 26,5 kg N ha–1 a–1, wobei 29 % der Flächen mehr als 5 kg N ha–1 a–1 freisetzten. Nur die Kiefernbestände wiesen eine signifikant (P < 0,05) geringere NO3–-Auswaschung auf als die Fichtenbestände. Der Median des Verhältnisses N-Austrag : N-Eintrag lag zwischen 0,04 und 0,11 für die Buchen-, Eichen- bzw. Kiefernbestände, während die Fichtenbestände ein Verhältnis von 0,24 aufwiesen und damit ein höheres Risiko der NO3–-Auswaschung darstellen. Nach Logarithmierung der Daten konnte der N-Eintrag zu 38 % die Varianz der N-Austräge erklären. Die Stratifizierung der Daten nach dem C:N-Verhältnis der Humusauflage oder dem obersten Mineralboden ergab, dass Waldböden mit einem C:N-Verhältnis < 25 (Median von 4,6 kg N ha–1 a–1) signifikant mehr NO3– freisetzten als Wälder mit einem C:N-Verhältnis > 25 (Median von 0,8 kg N ha–1 a–1). Im Vergleich zu dem gesamten Datensatz verbesserte die Stratifizierung der Daten nur die Beziehung zwischen N-Eintrag und N-Austrag für Flächen mit einem C:N-Verhältnis < 25 (r2 = 0,47) während die Beziehung für Flächen mit einem C:N-Verhältnis > 25 schwächer (r = 0,21) war. Unsere Ergebnisse deuten darauf hin, dass die NO3–-Auswaschung in deutschen Wäldern mit weiten C:N-Verhältnissen in der Humusauflage zunehmen kann, sofern die N-Deposition auf einem hohen Niveau verbleibt. Ferner kann das Potenzial der Wälder, anorganischen N zu speichern, mit enger werdenden C:N-Verhältnissen in den Humusauflagen abnehmen.
The aim of this study was to combine data on photosynthetic performance, growth and mineral nutrition of Quercus petraea, Fagus sylvatica and Acer pseudoplatanus growing six years under a Norway spruce canopy. Three years old saplings were planted on several adjoining plots from the
forest edge up to 35m inside the spruce forest on nutrient poor dystric cambisols. Growth parameters, photosynthetic capacity
and leaf nutrition were repeatedly measured on 11 to 13 selected plants for each species every year from 1996 to 2001. The
general performance of the plants growing along the light gradient from forest edge into the closed canopy decreased in the
order F.sylvatica, Q.petraea and A.pseudoplatanus. The photosynthetic performance of Acer declined from the second year onwards as consequence of low nutrient supply. The plants had in most cases higher leaf nitrogen
concentration in shade. This increase going along with declining light input was the best in Quercus and was found in Acer leaves only in the second year after the planting. The growth parameters of all investigated plants were not correlated to
the light environment within the range of canopy gap fraction between 0.05 and 0.62. However, the total leaf area as well
as nutrient amounts in the foliage were good predictors for total plant height and plant diameter at root collar of Fagus and Quercus, but failed in most cases for Acer. These results emphasise the important role of nutrient acquisition for young broadleaves introduced in Norway spruce stands
and underline the different requirements for nutrient supply at the species level.
Over the last 6 decades, atmospheric S deposition has peaked in some parts of the world, while simultaneously it continues to impact other regions of the globe. During this same time, we have increased considerably our ecosystem-level understanding of the consequences of atmospheric S deposition on aquatic, terrestrial and wetland systems. Biogeochemical cycling of S is highly complex in ecosystems having predominantly anaerobic zones, yet even in well-drained upland forests, we now know that many of the processes thought only to be dominant in wetlands must be considered to accurately evaluate S fluxes and cycling patterns.
This study evaluates chemical trends of seven acidified reservoirs and 22 tributaries in the Erzgebirge from 1993 to 2003. About 85% of these waters showed significantly (p < 0.05) declining concentrations of protons (-69%), nitrate (-41%), sulfate (-27%), and reactive aluminum (-50% on average). This reversal is attributed to the intense reduction of industrial SO2 and NOx emissions from formerly high levels, which declined by 99% and 82% in the German-Czech border region between 1993 and 1999. The deposition rates of protons and sulfur decreased by 70-90%. Since 1993, the dry deposition of total inorganic nitrogen diminished to a minor degree, but the wet deposition remained unchanged. The surface waters reflect a substantial decrease in Al exchange processes, a release of sulfur previously stored in soils, and an uptake of nitrate by forest vegetation. The latter effect may be supported by soil protection liming which contributed to the chemical reversal in almost 20% of the study waters.
In a previous study, a rapid acidification of soil solution was observed between 1987 and 1997 in a cryptopodzolic soil in southern Switzerland despite a reduction in acidic deposition. The molar ratio of base nutrient cations to aluminum (BC/Al) in the soil solution was used to assess acidification. The monitoring of the soil solution chemistry was continued at the same site between 1998 and 2003 to find out how long the delay in reaction to reduced deposition would last and whether the BC/Al ratios would recover. The reevaluation of all data collected during the 16-year observation period showed no clear improvement in the BC/Al ratios, except below the litter layer where the ratios greatly increased after 1998. Initial signs of recovery were also detected in the mineral horizons, the ratios stabilizing in the second part of the observation period. Sulfate concentrations decreased significantly below the litter mat in response to decreased S deposition. BC concentrations markedly declined below the litter layer and in the mineral horizons, which was attributed to the depletion of the BC exchangeable pool as a result of continued acidic deposition.
The mitigating effect of decreasing anthropogenic SO4 deposition on acidified soils and waters can be delayed by the release of previously stored soil SO4. We investigated SO4 pools and desorption in the weathered substrata (0.5-10 m depth) of a forested catchment on granite to quantify the importance of these layers to SO4 dynamics. Solid-phase materials from 10 boreholes to a maximum depth of 10 m were analyzed for water- and phosphate-extractable SO4, SO4 desorption, cation-exchange capacity (CEC), pH, and dithionite- and oxalate-extractable Fe (Fe(d) and Fe(o)) and Al (Al(d) and Al(o)). Seven of the investigated boreholes were used to monitor water table depth and to obtain samples for measurement of solution SO4 concentrations. The storage of phosphate-extractable SO4 in the weathered substrata was estimated at 90 kmol ha-1, of which ≃50 kmol ha-1 were water soluble. Sulfate pools and their desorption behavior were highly variable, which could partly be explained by the variation of pH and extractable Fe and Al contents of the samples. Sulfate concentrations in groundwater were dependent on the depth of groundwater table and corresponded with the depth gradients of solid-phase SO4. The SO4 pools of the substrata were apparently regulating solution concentrations. Thus, groundwater acidification in such aquifers will not be easily reversed by decreasing SO4 deposition because of the release of previously stored SO4.
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.
Long term trends of element fluxes in atmospheric deposition and of concentrations in seepage output of seven coniferous and deciduous forest stands in northwestern Germany have been evaluated for the period 1981 – 1994. Decreasing deposition rates of SO4 (50 – 70%) and H+ (60 – 80%) occured at all sites concomitant with the decline of SO2 emission rates in the former Federal Republic of Germany. Deposition of Ca, Mg, and K decreased at the Soiling and Gttinger Wald stands. During this period no consistent trends in the flux rates of NH4 and NO3 were apparent. Sulfate concentrations in soil solution decreased at the Soiling and Gttinger Wald stands, whereas an increase occured at Lange Bramke south slope. As a consequence of reduced deposition and mobile anion concentrations a decrease of Ca, Mg, K, Al, and Mn in soil solution has been observed at the Soiling stands. At the other stands trends of cations in soil solution are not consistent. Nitrate concentrations in soil solution decreased at the Gttinger Wald. A rising tendency with great fluctuations of NO3 concentrations occured at the Soiling spruce stand.
Some of the characteristics that complicate the analysis of water quality time series are non‐normal distributions, seasonality, flow relatedness, missing values, values below the limit of detection, and serial correlation. Presented here are techniques that are suitable in the face of the complications listed above for the exploratory analysis of monthly water quality data for monotonie trends. The first procedure described is a nonparametric test for trend applicable to data sets with seasonality, missing values, or values reported as ‘less than’: the seasonal Kendall test. Under realistic stochastic processes (exhibiting seasonality, skewness, and serial correlation), it is robust in comparison to parametric alternatives, although neither the seasonal Kendall test nor the alternatives can be considered an exact test in the presence of serial correlation. The second procedure, the seasonal Kendall slope estimator, is an estimator of trend magnitude. It is an unbiased estimator of the slope of a linear trend and has considerably higher precision than a regression estimator where data are highly skewed but somewhat lower precision where the data are normal. The third procedure provides a means for testing for change over time in the relationship between constituent concentration and flow, thus avoiding the problem of identifying trends in water quality that are artifacts of the particular sequence of discharges observed (e.g., drought effects). In this method a flow‐adjusted concentration is defined as the residual (actual minus conditional expectation) based on a regression of concentration on some function of discharge. These flow‐adjusted concentrations, which may also be seasonal and non‐normal, can then be tested for trend by using the seasonal Kendall test.
Statistical tests for monotonic trend in seasonal (e.g., monthly) hydrologic time series are commonly confounded by some of the following problems: nonnormal data, missing values, seasonality, censoring (detection limits), and serial dependence. An extension of the Mann‐Kendall test for trend (designed for such data) is presented here. Because the test is based entirely on ranks, it is robust against nonnormality and censoring. Seasonality and missing values present no theoretical or computational obstacles to its application. Monte Carlo experiments show that, in terms of type I error, it is robust against serial correlation except when the data have strong long‐term persistence (e.g., ARMA (1, 1) monthly processes with ϕ > 0.6) or short records (∼ 5 years). When there is no serial correlation, it is less powerful than a related simpler test which is not robust against serial correlation.
Water quality data for 56 long-term monitoring sites in eight European countries are used to assess freshwater responses to reductions in acid deposition at a large spatial scale. In a consistent analysis of trends from 1980 onwards, the majority of surface waters (38 of 56) showed significant (p ?0.05) decreasing trends in pollution-derived sulphate. Only two sites showed a significant increase. Nitrate, on the other hand, had a much weaker and more varied pattern, with no significant trend at 35 of 56 sites, decreases at some sites in Scandinavia and Central Europe, and increases at some sites in Italy and the UK. The general reduction in surface water acid anion concentrations has led to increases in acid neutralising capacity (significant at 27 of 56 sites) but has also been offset in part by decreases in base cations, particularly calcium (significant at 26 of 56 sites), indicating that much of the improvement in runoff quality to date has been the result of decreasing ionic strength. Increases in acid neutralising capacity have been accompanied by increases in pH and decreases in aluminium, although fewer trends were significant (pH 19 of 56, aluminium 13 of 53). Increases in pH appear to have been limited in some areas by rising concentrations of organic acids. Within a general trend towards recovery, some inter-regional variation is evident, with recovery strongest in the Czech Republic and Slovakia, moderate in Scandinavia and the United Kingdom, and apparently weakest in Germany.
Keywords: acidification, recovery, European trends, sulphate, nitrate, acid neutralising capacity
Long-term records of nitrogen in deposition and streamwater were analysed at 30 sites covering major acid sensitive regions in Europe. Large regions of Europe have received high inputs of inorganic nitrogen for the past 20-30 years, with an approximate 20% decline in central and northern Europe during the late 1990s. Nitrate concentrations in streamwaters are related to the amount of N deposition. All sites with less than 10 kgN ha -1 yr -1 deposition have low concentrations of nitrate in streamwater, whereas all sites receiving > 25 kgN ha -1 yr -1 have elevated concentrations. Very few of the sites exhibit significant trends in nitrate concentrations; similar analyses on other datasets also show few significant trends. Nitrogen saturation is thus a process requiring many decades, at least at levels of N deposition typical for Europe. Declines in nitrate concentrations at a few sites may reflect recent declines in N deposition. The overall lack of significant trends in nitrate concentrations in streams in Europe may be the result of two opposing factors. Continued high deposition of nitrogen (above the 10 kgN ha -1 yr -1 threshold) should tend to increase N saturation and give increased nitrate concentrations in run-off, whereas the decline in N deposition over the past 5-10 years in large parts of Europe should give decreased nitrate concentrations in run-off. Short and long-term variations in climate affect nitrate concentrations in streamwater and, thus, contribute "noise" which masks long-term trends. Empirical data for geographic pattern and long-term trends in response of surface waters to changes in N deposition set the premises for predicting future contributions of nitrate to acidification of soils and surface waters. Quantification of processes governing nitrogen retention and loss in semi-natural terrestrial ecosystems is a scientific challenge of increasing importance.
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.
Coweeta is one of the oldest continuously operating laboratories of its type in the world. For the first time, a complete review and summary of more than 50 years study of the hydrological and ecological responses of baseline and managed Southern Appalachian hardwood forests at Coweeta is now supplied by this volume. The long-term research approach represents a continuum of theory, experimentation and application using watersheds as landscape units of investigation. Thus, the information encompasses a wide range of interpretations and interests. In addition to in-depth analyses of terrestrial and stream processes, the breadth of coverage includes historical perspectives and relevance of ecosystem science to management needs. In a broader sense, the Coweeta research effort is considered from a perspective of national and international forest hydrology and ecology programs.
The isotopic composition of SO
42- in bulk precipitation, canopy throughfall, seepage water at three different soil depths, stream water, and groundwater was monitored in two forested catchments in the Black Forest (Germany) between November 1989 and February 1992. Isotope measurements on aqueous sulfate were complemented by δ34S-analyses on SO2 in the air, total sulfur and inorganic sulfate in the soil, and bedrock sulfur, in order to identify sources and biogeochemical processes affecting S cycling in catchments with base poor, siliceous bedrock. Stable S isotope data indicated that atmospheric deposition and not mineral weathering is the major source of S in both catchments since δ34S-values for sulfate in the soil, in seepage water, and in stream water were generally found to be similar to the mean δ34S-values of precipitation SO
42- (+2.1. However, δ18O-values of seepage water SO
42- at 30 cm and especially at 80 cm depth were depleted by several per mil with respect to those of the atmospheric deposition (+7.5 to +13.5. This indicates that in both catchments a considerable proportion of the seepage water SO
42- is derived from mineralization of carbon-bonded soil S and must therefore have cycled through the organic soil S pool. δ34S-values for different S compounds in the solid soil were found to differ markedly depending on S fraction and soil depth. Since atmospheric S deposition with rather constant δ34S-values was identified as the dominant S source in both catchments, this is interpreted as a result ofin situ isotope fractionation rather than admixture of isotopically different S. The differences between the δ34S-values of seepage water and soil sulfate and those of organic soil S compounds are consistent with a model in which SO
42- uptake by vegetation and soil microorganisms favours34SO
42- slightly, whereas during mineralization of organic soil S to aqueous SOSO
42-,32S reacts preferentially. However, the data provide evidence for negligible isotope fractionation during physico-chemical S transformations such as adsorption/desorption in aerated forest soils.
From the view point of the receiving ecosystem, a distinction is made between precipitation deposition and interception deposition. Precipitation deposition occurs by gravity and is the sum of deposition with rain and snow and as dust particles; the receiving surface has no influence on the deposition rate. Interception deposition is the sum of impaction of aerosols and droplets (fog, cloud droplets), and of gas absorption; the receiving surface influences the deposition rate greatly by its size, kind and chemistry. An approach is presented to calculate the rate of interception deposition on forest canopies and to account for the various processes. The approach rests on the measurement of precipitation (wet) deposition and throughfall. Flux balance equations are used to account for sink and source terms of the canopy. The approach is demonstrated with data from a beech and a spruce forest covering the period from 1969 to 1981. The data indicate that the S02 absorption in the canopy (dry deposition) is limited by the ability of the trees to buffer the protons produced during SO2 absorption in water films at inner and outer plant surfaces. Under conditions of high soil acidity and low tree vitality, the buffer ability of the trees can cease. This limits dry deposition of SO2 to very low rates.
Zusammenfassung In zwei kleinen Wassereinzugsgebieten im Hochschwarzwald wurde im Zeitraum 1989–1998 die zeitliche Dynamik der Wasserqualität
in Abhängigkeit von der Abflussmenge untersucht. In einem der Einzugsgebiete war 1990 eine forstübliche dolomitische Kalkung
(4 t ha−1) erfolgt. Für eine episodische Versauerung bei hohen Abflüssen ist in erster Linie die Mobilisierung von Nitrat verantwortlich.
Säurepufferung und Kationenzusammensetzung sind stark an die zeitlich variablen Fließwege im Einzugsgebiet gekoppelt. Die
Bodenkalkung bewirkte nur verhältnismäßig geringe Veränderungen der Wasserqualität. Allerdings war die Säureneutralisationskapazität
bei Spitzenwerten des Abflusses tendenziell leicht erhöht. Trotz kalkungsbedingter verstärkter mikrobieller Aktivität und
Nitrifikation in den Oberböden blieben die Nitrat-Konzentrationen im Bachwasser nahezu unverändert. Angesichts der veränderten
Depositionssituation, wonach der S-Eintrag in jüngster Vergangenheit stark zurückgegangen ist, der N-Eintrag aber anhält,
ist mittel- bis langfristig mit einer weiteren Verbesserung der N-Verfügbarkeit in Wäldern zu rechnen. Somit besteht ein zunehmendes
Risiko für NO3
−-Auswaschung nach Kalkung. Diese Entwicklung ist bei der künftigen Planung großflächiger Waldkalkungen zu beachten.
In two small watersheds in the upper Black Forest (SW Germany) the temporal variation of water quality in relation to runoff dynamics was investigated during the period of 1989 through 1998. In 1990, one of the two watersheds was limed according to forest management practice (4t dolomite ha-1). Episodic acidification during high-flow conditions is primarily due to the mobilization of nitrate. Acid buffering and cation composition were related to the time-variable flow paths in the watershed. The effects of soil liming on water quality were relatively small. Nevertheless, the acid neutralizing capacity during peak runoff events tended to be slightly improved. Even though microbial activity and nitrification were enhanced in the top-soils as a result of liming, the nitrate concentrations in the stream increased only slightly. With regard to recent changes in the atmospheric deposition pattern (distinct decline in S while N endures) in the middle to long term a better availability of N in forests can be expected. As a consequence, there is an increasing risk of NO3- leaching after liming. This development should be taken into account when large-scale liming operations in forests are planned in the future.
A group of Nordic experts has tried to draw conclusions on critical loads for sulphur and nitrogen. The critical load is defined as “The highest load that will not cause chemical changes leading to long-term harmful effects on most sensitive ecological systems”.
Most soils, shallow groundwaters and surface waters would probably not be significantly changed by a load of 10–20 keq H+·km2·yr−1 in areas with a low content of base cations in the deposition. The total deposition of hydrogen ions in southwestern Scandinavia is in the order of 100 keq ·km−2·yr−1.
The long-term critical load for nitrogen is in the range of 10–20 kg N·ha·1-yr−1 in most forest ecosystems. In high productive sites it might be as high as 20–45 kg N·ha− yr−1 in southern Sweden, and amounts to 30–40 kg·ha−1·yr−1 and even more over large areas in central Europe.
The current deposition of sulphur and nitrogen must be substantially reduced to keep the long-term changes in sensitive ecosystems within acceptable limits.
A procedure was developed for the fractionation of aqueous aluminum. This procedure results in the determination of acid-soluble aluminum, non-labile monomeric aluminum and labile monomeric aluminum. Acid-soluble aluminum is thought to include colloidal aluminum and extremely non-labile organic complexes. Non-labile monomeric aluminum is thought to include monomeric alumino-organic complexes. Labile monomeric is comprised of aquo aluminum as well as inorganic complexes of aluminum. The inorganic speciation of aluminum may be calculated by using labile monomeric aluminum, pH, fluoride and sulfate data with a chemical equilibrium model.This procedure was evaluated using synthetic and natural water solutions. In natural waters, levels of labile monomeric aluminum increased exponentially with decreases in solution pH, while non-labile monomeric aluminum was strongly correlated with organic carbon concentration. Non-labile monomeric aluminum was observed to be relatively insensitive to changes in solution pH. Results of the aluminum fractionation procedure were in relative agreement with an independent evaluation using the fluoride ion selective electrode.
The acid-base chemistry of streams and lakes is regulated by the amount and composition of atmospheric deposition and by biogeochemical processes in the catchment and within streams and lakes. In this paper the influence of nitrogen (N) and sulfur (S) compounds will be discussed (a) because they are major constituents of atmospheric deposition that have recently become the focus of critical loads assessments in Europe and North America, and (b) because they are essential nutrients for most biota and cycle naturally through terrestrial and aquatic ecosystems. In order to evaluate the relative impact of atmospheric inputs on freshwater acidity, it is necessary to clearly define acidification'' and to understand; the mechanisms of change caused or mediated by natural and anthropogenic processes.
There has been a significant reduction in anthropogenic acid deposition
in Europe and North America, and now we need to gauge the rate and extent
of ecosystem recovery. Stoddard et al.1 have reported
a widespread aquatic recovery from acidification in European ecosystems in
response to a fall in sulphate deposition. But many sites in central Europe
are showing a significant delay in aquatic recovery from acidification, or
even no recovery at all, and only some of them show biological recovery of
waters or a recovery from soil acidification. Ecosystem management still needs
to consider the consequences of acidification.
The decrease in anthropogenic deposition, namely SO42— and SO2, in European forest ecosystems during the last 20 years has raised questions concerning the recovery of forest ecosystems. The aim of this study was to evaluate if the long term data of element concentrations at the Fichtelgebirge (NE-Bavaria, Germany) monitoring site indicates a relationship between the nutrient content of needles and the state of soil solution acidity. The soil at the site is very acidic and has relatively small pools of exchangeable Ca and Mg. The trees show medium to severe nutrient deficiency symptoms such as needle loss and needle yellowing. The Ca and Mg concentrations in throughfall decreased significantly during the last 12 years parallel to the significant decline in the throughfall of H+ and SO42— concentrations. Soil solution concentrations of SO42—, Ca and Mg generally decreased while the pH value remained stable. Aluminum concentrations decreased slightly, but only at a depth of 90 cm. Simultaneously a decrease in the molar Ca/Al and Mg/Al ratios in the soil solution was observed. Ca and Mg contents in the spruce needles decreased, emphasizing the relevance of soil solution changes for tree nutrition. The reasons for the delay in ecosystem recovery are due to a combination of the following two factors: (1) the continued high concentrations of NO3— and SO42— in the soil solution leading to high Al concentrations and low pH values and, (2) the decreased rates of Ca and Mg deposition cause a correlated decrease in the concentration of Ca and Mg in the soil solution, since little Ca and Mg is present in the soil's exchangeable cation pools. It is our conclusion that detrimental soil conditions with respect to Mg and Ca nutrition as well as to Al stress are not easily reversed by the decreasing deposition of H+ and SO42—. Thus, forest management is still confronted with the necessity of frequent liming to counteract the nutrient depletion in soils and subsequent nutrient deficiencies in trees.Einfluss reduzierter atmosphärischer Deposition auf die Bodenlösungschemie und Elementgehalte in Fichtennadeln in NO-BayernDie Abnahme der anthropogenen Deposition, vor allem des SO42—, während der letzten 20 Jahre in Europa wirft die Frage nach einer Erholungsfähigkeit von Waldökosystemen auf. Das Ziel dieser Studie war eine Bewertung von Nährstoffgehalten in Nadeln im Zusammenhang mit dem Versauerungsgrad der Bodenlösung auf einer Dauerbeobachtungsfläche im Fichtelgebirge (NO-Bayern, Deutschland). Die Böden der Fläche sind extrem sauer und haben niedrige Vorräte an austauschbarem Ca und Mg. Der Baumbestand zeigt mittlere bis starke Schädigung in Form von Nadelvergilbung und Nadelverlusten. Aufgrund einer drastischen Reduktion der anthropogenen Emissionen ist neben den signifikant abnehmenden H+- und SO42—-Konzentrationen ein paralleler Rückgang der Ca- und Mg-Konzentrationen im Bestandsniederschlag während der letzten 12 Jahre zu verzeichnen. Während die SO42—-, Ca- und Mg-Konzentrationen in der Bodenlösung generell abnahmen, blieb der pH-Wert unverändert. Die Aluminiumkonzentration in der Bodenlösung zeigte einen leichten Rückgang, allerdings nur in 90 cm Tiefe. Dabei war ein Rückgang der molaren Ca/Al- und Mg/Al-Verhältnisse zu beobachten. Gleichzeitig nahmen die Ca- und Mg-Gehalte in den Fichtennadeln ab, was die Bedeutung der Bodenlösungschemie für den Ernährungszustand der Bäume verdeutlicht. Die Gründe für eine Verzögerung der Erholung des Ökosystems ergeben sich aus der Kombination von (1) anhaltend hohen NO3—- und SO42—-Konzentrationen in der Bodenlösung, die gleichbleibend niedrige pH-Werte und hohe Al-Konzentrationen verursachen und (2) den rückläufigen Ca- und Mg-Depositionen, die zusammen mit geringeren austauschbaren Vorräten niedrige Bodenlösungskonzentrationen von Ca und Mg verursachen. Wir schließen daraus, dass ungünstige Bodenbedingungen hinsichtlich der Ca- und Mg-Versorgung und des Al-Stresses sich nicht nur durch eine Abnahme der H+- und SO42—-Einträge verbessern. Daher werden Forstwirtschaftler auch weiterhin Kalkungsmaßnahmen einplanen müssen, um Bodenverarmung und Nährstoffmangel in Bäumen entgegenzuwirken.
The deposition of nitrogen from the atmosphere to coniferous forests poses the risk of N saturation and disruption of the N cycle. Beginning in April 1991, we have conducted a whole-ecosystem manipulation of N deposition at a mature coniferous forested-catchment at Gårdsjön, SW Sweden. We have added in weekly portions of about 40 kg NH4NO3N ha−1 yr−1 in 5% extra water to the ambient 11 kg NH4NO3N ha−1 yr−1 in throughfall. The Gårdsjön experiment is part of the European NITREX project (Nitrogen saturation experiments). Both the annual mean concentrations and peak concentrations of nitrate in runoff increased dramatically in response to the chronic additions of N. The seasonal pattern and the yearly amount of N loss changed during the 5 years of treatment. During the first years of treatment, concentrations of NO3− were low during the growing season and high during the winter; during the fourth and fifth years, elevated concentrations were present also during the summer. Ammonium concentrations, although generally much lower than NO3−, followed the same seasonal pattern. The inorganic N lost during the 5 years of treatment was 0.6%, 1.1%, 5.0%, 5.7% and 4.5% respectively, of the annual inorganic N input. In the fifth year, drought and generally very low runoff led to moderate N loss despite the high NO3− and NH4+ concentrations. Sulphate, inorganic Aln+, H+ and Na+ concentrations were significantly lower during the treatment period relative to the untreated control catchment while NO3−, NH4+, K+ and Ca2+ concentrations increased. The N concentrations in the runoff indicate incipient N saturation at the manipulated catchment. But the experimental dramatic increase in N deposition occurred so rapidly that the forest ecosystem has not yet had the opportunity to adjust and respond. Although symptoms of N saturation were induced over a relatively short time by increasing atmospheric deposition of N, the nitrogen status of the ecosystem is clearly in a state of transition. The rate of response suggests that at ambient N, deposition of 11 kg inorganic N ha−1 yr−1, the ecosystem is near the threshold at which additional N inputs cause significant NO3− leaching.
As a basis for experimentation, inputs and outputs of biogeochemicals were observed in coniferous stands in Denmark, the Netherlands, Germany and Ireland. The range of deposition observed is characteristic of populated regions of northwest Europe, from only moderately polluted Atlantic areas through decreasing marine influence and increasing deposition of anthropogenic nitrogen and sulphur. In intensive agricultural regions, ammonium inputs are high enough to cause nitrogen saturation of ecosystems, and nitrificationacidification is a major soil process. Co-deposition of ammonia and sulphur dioxide may be significantly increasing loads of N and S in forests in the region. Input-outputs are balanced for seasalts in the maritime sites, and sulphur outputs from the rooting zone also reflect the inputs to a large degree on these sites. Mobilisation of cations, notably aluminium, apparently occurs as a result of acidity generated by nitrogen transformations.
Results are presented from the research project Arinus which investigates biogeochemical cycling in Norway spruce (Picea abies KARST.) ecosystems in the Black Forest (SW Germany) and effects of experimental (NH4
2SO4 additions. The interaction of the terrestrial and aquatic system is assessed using an integrated approach which combines flux measurements in representative plots on the stand level with input-output budgets of small catchments. The approach, field installations and experimental manipulations are described. Results from element flux measurements in the untreated systems are presented and processes controlling N and S transformations are discussed for two catchments representing contrasting site conditions. Even though the S budget is negative for both systems there is a distinct difference in the relation between organicvs. inorganic S fractions in the soil. Sulfate mineralization and desorption, respectively are discussed as controlling processes. Sulfate retention is not only a function of soil properties, but also of water fluxes and pathways. The uptake of added SO
4
2–
was highly controlled by the counter-cation. Microbial N retention in the soil was highly influenced by the site management history. The extent of streamwater acidification was highly dependent on the transformations and mobility of N and S in the soils which in turn controlled cation leaching and alkalinity.
Magnesium deficiency has played a prominent role in recent forest decline phenomena. Symptoms of acute Mg deficiency (conifers:
tip yellowing of older needles; deciduous species: intercostal chlorosis in leaves) have been observed in many regions of
the world (Hüttl, 1991). In order to understand the differences in Mg supply between sites and temporal developments, a thorough
analysis of the bio-geochemical cycling of this element and major processes is necessary.
NITREX is a consortium of European experiments in which nitrogen deposition is drastically changed for whole catchments or large forest stands at eight sites spanning the present-day gradient of nitrogen deposition across Europe. NITREX focuses on the impact of nitrogen deposition on forest ecosystems, in particular the factors and processes affecting ‘nitrogen saturation’. A large number of ecosystem processes and components are investigated as part of NITREX to identify and quantify the factors which lead to changes in nitrogen cycling and outputs due to experimental changes in nitrogen inputs. The data are used to develop and test several types of nitrogen models. NITREX is linked to several other European research projects, as well as to similar large-scale ecosystem experiments in North America.
Eminent contributors present articles which evaluate the causes, consequences and reversibility of freshwater acidification--past, present and future.
One of the most pressing issues currently facing environmental scientists is the need to predict the effects of acid deposition on terrestrial and aquatic ecosystems. This book focuses on those systems in which acid deposition is most widespread and deleterious and analyzes the effects on the soil-plant system and on the composition of the solution that is released to surface waters and groundwaters. With the help of a quantitative model, the authors synthesize existing knowledge into a conceptual model consistent with established physio-chemical principles and the bulk of information available. Contents: Introduction. - Soil Acidification: Fundamental Concepts. - The Sulfur System. - The Nitrogen System. - Soil Solution Interactions. - Forest Element Cycling. - The Aquatic Interface. - Soil Sensitivity. - Conclusion. - References. - Appendix: Model Documentation. - Index.
Dresden, Techn. Univ., Fak. für Forst-, Geo- u. Hydrowiss. [Tharandt], Diss., 1998.
Dresden, Techn. Universiẗat, Diss., 1995.
We investigated the relations between mountain streamwater chemistry and atmospheric pollution in an arca of 1611 km2 of the Czech Republic by comparing concentrations of SO4. NO3, Cl, Ca and the pH at 432 localities at the time of high (1984-1986) and relatively low (1996-2000) acidic atmospheric deposition. Medians of Cl. SO4, and NO3 decreased by 17, 96 and 60 microeq l(-1), or by 23, 17 and 49%, respectively, during 12 +/- 2 years. The decreased Cl corresponds to decreased emission of industrial Cl (as HCl). The decreased stream SO4 was proportionally lower than the 71% decrease in S-emissions due to leaching of previously accumulated SO4 from soils and non-zero background concentrations. Decreases of NO3 up to 60% in streamwaters with pH < or = 6 was greater than the decrease of N emission in central Europe, about 35%. Extensive regional decrease of NO3 is surprising and is probably described for the first time. The difference in NO3 concentrations between the two periods was probably enhanced by (a) an increase of mineralisation of forest floor in the mid-1980s and (b) by higher uptake of N in the late-1990s. The median pH of the 432 streams did not change but the pH of the sub-population with pH < 6 in the mid-1980s recovered substantially. The pH of circum-neutral streams (pH > 6.5) decreased even as acidic atmospheric deposition decreased.
Nitrogen saturation, in the sense that nitrogen additions to an ecosystem lead to losses of the same order of magnitude, is analyzed as an interplay between a plant subsystem and a soil subsystem. The plant system is defined by its nitrogen productivity, which allows calculations of the maximum amount of nitrogen that can be held in, and the maximum nitrogen flux density that can be utilized by, the plant subsystem. The most important response of the soil subsystem is a change in the microbial nitrogen concentration, from which the nitrogen absorption capacity can be derived. It is shown that of the two subsystems the soil must always saturate first. The time to reach saturation depends strongly on site history in terms of the sources of litter forming the soil organic matter and on the ratio between the external nitrogen inflows and the litter nitrogen flow.
Transboundary acid deposition in Europe. EMEP (Co-operative Programme for Monitoring and Evaluation of the Long-Range Transmission of Air pollutants in Europe) summary report 1999
Tarrasón L. and Schaug J. (eds) 1999. Transboundary acid deposition in Europe. EMEP (Co-operative
Programme for Monitoring and Evaluation of the Long-Range Transmission of Air pollutants in Europe) summary report 1999. Norwegian Meteorological Institute Research Report 83.
Sulfat-Dynamik in sauren Waldböden -Sorptionsvermögen und Prognose bei nachlassenden Depositionen
- C Alewell
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Are there signs of acidification reversal after two decades of reduced acid input in the low mountain ranges of Germany?
- C Alewell
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Zeitliche Dynamik der Wasser/ -und Elementflüsse in Waldökosystemen
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Armbruster M. 1998. Zeitliche Dynamik der Wasser/ -und Elementflüsse in Waldökosystemen.
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Brahmer G. 1990. Wasser-und Stoffbilanzen bewaldeter Einzugsgebiete im Schwarzwald unter beson-derer Berücksichtigung naturräumlicher Ausstattung und atmogener Einträge. Freiburger Boden-kundl. Abh Vol. 25., 295 p. Cummins T., Beier C., Blanck K., de Visser P.H.B., Farrell E.P., Rasmussen L. et al. 1995. The EX-MAN project. Biogeochemical fluxes in plantation forests on acid soils. Water Air Soil Pollut. 85: 1653–1658.
Sulfat-Dynamik in sauren Waldböden – Sorptionsvermögen und Prognose bei nachlas-senden Depositionen Are there signs of acidification reversal after two decades of reduced acid input in the low mountain ranges of Germany?
- C Alewell
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Dynamik von Aluminium und ökotoxischen Al-Bindungsformen in kleinen Fließgewässern nach Forstdüngung mit sulfatischen Magnesiumsalzen
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The relative importance of sulfur and nitrogen compounds in the acidification of fresh water Acidification of Freshwater Ecosystems: Implications for the Future. Dahlem Workshop Reports
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van Miegroet H. 1994. The relative importance of sulfur and nitrogen compounds in the acidification of fresh water. In: Steinberg C.E.W. and Wright R.F. (eds), Acidification of Freshwater Ecosystems: Implications for the Future. Dahlem Workshop Reports. Environmental Sciences Research Report 14. Wiley and Sons, Chichester, pp. 33–49.
Untersuchungen von Waldökosystemen im Erzgebirge als Grundlage für einen ökologisch begründeten Waldumbau
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Die chemische Zusammensetzung der wichtigsten Grundgesteine Sachsens als Grundlage für eine Beurteilung der Nährstoffverhältnisse in Waldböden
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Bedeutung von ökosysteminternen Umsätzen und Nutzungseingriffen für den Stoff-haushalt von Waldökosystemen. Freiburger Bodenkundl Solute fluxes and sulfur cycling in forested catchments in SW Germany as influenced by experimental (NH 4 ) 2 SO 4 treatments
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Feger K.H. 1993. Bedeutung von ökosysteminternen Umsätzen und Nutzungseingriffen für den Stoff-haushalt von Waldökosystemen. Freiburger Bodenkundl. Abh Vol. 31., 237 p. Feger K.H. 1995. Solute fluxes and sulfur cycling in forested catchments in SW Germany as influenced by experimental (NH 4 ) 2 SO 4 treatments. Water Air Soil Pollut. 79: 109–130.