Reversibility of acidification of mountain lakes after reduction in nitrogen and sulphur emissions in Central Europe

Abstract

Abstract-The reversal of water acidification has been recently indicated by both empirical data and experiments. The world's largest whole-ecosystem "experiment" involving -30% and -40% reduction in nitrogen and sulfur emissions, respectively, has occurred in Central Europe due to the political and economic changes in the postcommunist countries since 1989. Parallel decreases in deposition rates of SO,*-, NO,-, and NH,+ have resulted in ,a rapid reversal in hydrochemistry of acidified lakes in the Sumava Mountains and the High Tatra Mountains. Concentrations of SO,>-and NO,-in lakes were reduced by 11-14 and 13-32 mmol m-', respectively, between the late 1980s and middle 1990s. Leaching of calcium, magnesium, and aluminum from the watersheds decreased while lake water pH and alkalinity increased. The immediate decline in NO,-concentrations after reduced nitrogen emissions has suggested a rapid reversibility of nitrogen saturation of the mountainous ecosystems in response to decreased amounts of nitrogen deposition.In the last two decades, studies have focused on the level of freshwater acidification in response to two opposing processes: reduction of acid deposition, and nitrogen saturation of terrestrial ecosystems. Reversibility of soil and water acidification has been indicated by both empirical data and experiments. Decreases in sulfur emission in North America and Europe, as well as experimentally reduced acid deposition, have initiated reversal of acidification and the recovery of affected ecosystems (Schindler 1988;Wright and Hauhs 1991). In contrast to the reported decreasing trends in SOd2-concentrations in acidified lakes, levels of NO,-have largely increased in the last two decades (e.g. Henriksen and Brakke 1988;Murdoch and Stoddard 1992). The reason for this is increased leaching of NO,-from N-saturated watersheds exposed to chronically high atmospheric deposition of N (Stoddard 1994;Dise and Wright 1995). NO,-outputs from the N-saturated watersheds have been thus far decreased only in large-scale experiments with drastically reduced loads of SO, 2-, NO,-, and NH, ' (Wright et al. 1988). Because the level of N emissions over the Northern Hemisphere was relatively stable in the last decade, no empirical evidence exists on the response of NO,-leaching from N-saturated terrestrial ecosystems to reduced N deposition.We herein integrate results from published and original data in order to evaluate (1) historical changes in acidifica-$on of lakes in two Central European mountain ranges (the Sumava Mountains and the High Tatra Mountains) in response to the trends in Central European emissions of S and N pollutants, and (2) empirical data on reversibility of acidification of the lakes after economically derived reduction in S and N emissions in former East Germany, Poland; Czech Republic, and Slovakia in the early 1990s. Our data represent the first observations of an immediate response of the N-saturated sites to the nonexperimental reduction in the atmospheric deposition of NO,-and NH,'.The mountain lakes...

Sulphur and nitrogen fluxes and budgets in the Bohemian Forest and Tatra Mountains during the Industrial Revolution (1850-2000)

“…data). The carbonate buffering system of WS and MO was not depleted during acidification and has been recently recovered in VW (Kopácek et al, 1998). Trends in concentrations of SO 4 and NO 3 in WS, MO, and VW come from Stangenberg (1938), Bombówna, (1965, Henriksen et al (1992), Bombówna and Wojtan (1996), and Kopácek and Stuchlík (1994 and unpubl.…”

“…Despite their relatively rapid reversal from acidification and N saturation (Kopácek et al, 1998;Veselý et al, 1998), both lakes are still acidic, with elevated concentrations of aluminium (Al) ( Table 1). Trends in concentrations of SO 4 , NO 3 , and NH 4 in CN and CT come from Jírovec and Jírovcová (1937), Veselý et al (1998), Procházková and Blažka (1999), and Stuchlík and Kopácek (unpubl.…”

“…Parallel decreases in deposition rates of SO 4 , nitrate (NO 3 ), and ammonium (NH 4 ) have resulted in relatively rapid improvement in water quality in acidified mountain lakes in this area (e.g. Kopácek et al, 1998;Veselý et al, 1998).…”

Recovery from acidification in European surface waters

“…Christophersen et al, 1990;Reynolds et al, 1997), regions (e.g. Harriman et al, 1995;Soulsby et al, 1997;Veselý et al, 1998;Kopácek et al, 1998;Mosello et al, 2000) and countries (e.g. Mannio and Vuorenmaa, 1995;Skjelkvåle et al 1998;Wilander and Lundin, 1999;Monteith and Evans, 2000).…”

Forest Die-Back Modified Plankton Recovery from Acidic Stress

“…Moreover, the Bohemian Forest has exhibited the largest changes in acidic deposition due to 86, 53, and 35 % reduction in sulfur dioxide, nitrogen oxides, and ammonia emissions, respectively, in central Europe since the late 1980s (Kopáček et al 2012). Due to small and geologically sensitive catchments covered with coniferous forests, the Bohemian Forest lakes have rapidly shown substantial recovery of water chemistry (Kopáček et al 1998;Vrba et al 2003a). The biotic response, however, has lagged for a decade or even longer .…”