scholarly journals Norwegian lakes show widespread recovery from acidification; results from national surveys of lakewater chemistry 1986-1997

1998 ◽  
Vol 2 (4) ◽  
pp. 555-562 ◽  
Author(s):  
B. L. Skjelkvåle ◽  
R. F. Wright ◽  
A. Henriksen
Keyword(s):  
Base Cations ◽  
Chemical Recovery ◽  
N Leaching ◽  
National Scale ◽  
Western Norway ◽  
Acid Neutralising Capacity ◽  
Recovery From Acidification ◽  
Lakewater Chemistry ◽  
Southern Norway ◽  
Eastern Norway

Abstract. Surveys of 485 lakes in Norway conducted in 1986 and again in 1995 reveal widespread chemical recovery from acidification. Sulphate concentrations in lakes have decreased by 40% in acidified areas in southern Norway. This decrease has been compensated about 25% by decreases in concentrations of base cations and of 75% by increased Acid Neutralising Capacity (ANC). The increased ANC in turn reflects lower concentrations of acidic cations Aluminum (ALn+) and Hydrogen (H+). A sub-set of 78 of the 485 lakes sampled yearly between 1986 and 1997 shows that, at first most of the decrease in non-marine sulphate (SO4*) was compensated by a decrease in base cations, such that ANC remained unchanged. Then as SO4* continued to decrease, the concentrations of non- marine calcium and magnesium ((Ca+Mg)*) levelled out. Consequently, ANC increased, and H+ and Aln+ started to decrease. In eastern Norway, this shift occurred in 1989–90, and came slightly later in southern and western Norway. Similar shifts in trends in about 1991–92 can also be seen in the non-acidified areas in central and northern Norway. This shift in trends is not as pronounced in western Norway, perhaps because of the confounding influence of sea-salt episodes on water chemistry. This is the first documented national-scale recovery from acidification due to reduced acid deposition. Future climate warming and potentially increased N-leaching can counteract the positive trends in recovery from acidification.

scholarly journals Recovery from acidification of lochs in Galloway, south-west Scotland, UK: 1979-1998

2001 ◽  
Vol 5 (3) ◽  
pp. 421-432 ◽  
Author(s):  
R. C. Ferrier ◽  
R. C. Helliwell ◽  
B. J. Cosby ◽  
A. Jenkins ◽  
R. F. Wright
Keyword(s):  
General Pattern ◽  
Base Cations ◽  
Rapid Decline ◽  
Sea Salts ◽  
South West ◽  
Acid Neutralising Capacity ◽  
Sulphate Deposition ◽  
Recovery From Acidification ◽  
Chloride Concentrations

Abstract. The Galloway region of south-west Scotland has historically been subject to long-term deposition of acidic precipitation which has resulted in acidification of soils and surface waters and subsequent damage to aquatic ecology. Since the end of the 1970s, however, acidic deposition has decreased substantially. The general pattern is for a rapid decline in non-marine sulphate in rainwater over the period 1978-1988 followed by stable concentrations to the mid-1990s. Concentrations of nitrate and ammonium in deposition have remained constant between 1980 and 1998. Seven water quality surveys of 48 lochs in the Galloway region have been conducted between 1979 and 1998. During the first 10 years, from 1979, there was a major decline in regional sulphate concentrations in the lochs, which was expected to have produced a decline in base cations and an increase in the acid neutralising capacity. But sea-salt levels (as indicated by chloride concentrations) were approximately 25% higher in 1988 than in 1979 and thus short-term acidification due to sea-salts offset much of the long-term recovery trend expected in the lochs. During the next 10 years, however, the chloride concentrations returned to 1979 levels and the lochs showed large increases in acid neutralising capacity despite little change in sulphate concentrations. From the observed decline in sulphate deposition and concentrations of sulphate in the lochs, it appears that approximately 75% of the possible improvement in acid neutralising capacity has already occurred over the 20-year period (1979-1998). The role of acid deposition as a driving factor for change in water chemistry in the Galloway lochs is confounded by concurrent changes in other driving variables, most notably, factors related to episodic and year-to-year variations in climate. In addition to inputs of sea-salts, climate probably also influences other chemical signals such as peaks in regional nitrate concentrations and the sharp increase in dissolved organic carbon during the 1990s. Keywords: acidification, recovery, Galloway, sulphur, nitrogen

Chemical composition of the Tatra Mountain lakes: Recovery from acidification

Biologia ◽  
2006 ◽  
Vol 61 (18) ◽  
Author(s):  
Jiří Kopáček ◽  
Evžen Stuchlík ◽  
David Hardekopf
Keyword(s):  
Base Cations ◽  
Water Recovery ◽  
Total Organic Nitrogen ◽  
Alpine Zone ◽  
Acid Neutralising Capacity ◽  
Forest Lakes ◽  
Recovery From Acidification ◽  
Regional Basis ◽  
The Tatra Mountains ◽  
Norway Spruce Forest

AbstractNinety-one lakes distributed along the Tatra Mountains (most of lakes > 1 ha and 65% of lakes > 0.01 ha) were sampled and analysed for ionic and nutrient composition in September 2004 (15 years after reduction in acid deposition). Eighty-one lakes were in alpine zone and ten lakes in Norway spruce forest. The results were compared to similar lake surveys from 1994 (the beginning of water recovery from acidification) and 1984 (maximum acidification). Atmospheric deposition of SO42− and inorganic N decreased 57% and 35%, respectively, in this region from the late 1980s to 2000. Lake water concentrations of SO42− and NO3− have decreased both by ∼50% on average (to 23 and 19 μmol L−1, respectively, in 2004) since 1984. While the decrease in SO42− concentrations was stable throughout 1984–2004, most of the NO3− decrease occurred from 1994 to 2004. The declines in SO42− and NO3− concentrations depended on catchment coverage with vegetation, being most rapid for SO42− in forest lakes and for NO3− in rocky lakes. Concentrations of the sum of base cations (dominated by Ca2+) significantly decreased between 1984 and 2004, with the highest change in rocky lakes. Most of this decline occurred between 1994 and 2004. Acid neutralising capacity (ANC) did not change in the 1984–1994 period, but increased on average by 29 μmol L−1 between 1994 and 2004, with the highest change in rocky lakes. Over the last decade, the proportion of lakes with ANC > 150 μmol L−1 increased from 15% to 21% and that of ANC < 20 μmol L−1 decreased from 37% to 20%. The highest decline in H+ and Al concentrations occurred in the most acid lakes. On a regional basis, no significant change was observed for total phosphorus, total organic nitrogen, and dissolved organic carbon (DOC) in the 1994–2004 period. However, these parameters increased in forest lakes, which exhibited an increasing trend in DOC concentrations, inversely related (P < 0.001) to their decreasing ionic strength (30% on average in 1994–2004).

scholarly journals Recovery from acidification in European surface waters

2001 ◽  
Vol 5 (3) ◽  
pp. 283-298 ◽  
Author(s):  
C. D. Evans ◽  
J. M. Cullen ◽  
C. Alewell ◽  
J. Kopácek ◽  
A. Marchetto ◽  
...  
Keyword(s):  
Surface Waters ◽  
Base Cations ◽  
Quality Data ◽  
Water Quality Data ◽  
Large Spatial Scale ◽  
The United Kingdom ◽  
Acid Neutralising Capacity ◽  
Recovery From Acidification ◽  
The Uk

Abstract. 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

scholarly journals Recovery from acidification of lakes in Finland, Norway and Sweden 1990–1999

2001 ◽  
Vol 5 (3) ◽  
pp. 327-338 ◽  
Author(s):  
B. L. Skjelkvåle ◽  
J. Mannio ◽  
A. Wilander ◽  
T. Andersen
Keyword(s):  
Base Cations ◽  
Strong Acid ◽  
Nordic Countries ◽  
Sulphur Deposition ◽  
Ionic Strength Effect ◽  
National Monitoring ◽  
Acid Neutralising Capacity ◽  
Sulphate Deposition ◽  
Recovery From Acidification ◽  
A Minor

Abstract. Sulphate deposition has decreased by about 60% in the Nordic countries since the early 1980s. Nitrogen deposition has been roughly constant during the past 20 years, with only a minor decrease in the late 1990s. The resulting changes in the chemistry of small lakes have been followed by national monitoring programmes initiated in the 1980s in Finland (163 lakes), Norway (100 lakes) and Sweden (81 lakes). These lakes are partly a subset from the survey of 5690 lakes in the Northern European lake survey of 1995. Trend analyses on data for the period 1990-1999 show that the non-marine sulphate concentrations in lakes have decreased significantly in 69% of the monitored lakes. Changes were largest in lakes with the highest mean concentrations. Nitrate concentrations, on the other hand, were generally low and showed no systematic changes. Concentrations of non-marine base cations decreased in 26% of the lakes, most probably an ionic-strength effect due to the lower concentrations of mobile strong-acid anions. Acid neutralising capacity increased in 32% of the lakes. Trends in recovery were in part masked by large year-to-year variations in sea-salt inputs and by increases in total organic carbon concentrations. These changes were most probably the result of climatic variations. Nordic lakes, therefore, show clear signs of recovery from acidification. Recovery began in the 1980s and accelerated in the 1990s. Reductions in sulphur deposition are the major "driving force" in the process of recovery from acidification. Further recovery can be expected in the next 10 years if the Gothenburg protocol on emissions of acidifying pollutants is implemented. Keywords: Nordic countries, sulphur deposition, lakes, recovery

scholarly journals Acid deposition, land-use change and global change: MAGIC 7 model applied to Aber, UK (NITREX project) and Risdalsheia, Norway (RAIN and CLIMEX projects)

1998 ◽  
Vol 2 (4) ◽  
pp. 385-397 ◽  
Author(s):  
R. F. Wright ◽  
B. A. Emmett ◽  
A. Jenkins
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Acid Deposition ◽  
Base Cations ◽  
Nitrogen Addition ◽  
Scale Model ◽  
N Leaching ◽  
Catchment Scale ◽  
Acid Neutralising Capacity ◽  
Potential Tool

Abstract. Nitrogen processes are now included in a new version of MAGIC (version 7), a process-oriented catchment-scale model for simulating runoff chemistry. Net retention of nitrogen (N) is assumed to be controlled by plant uptake and the carbon/nitrogen (C/N) ratio of soil organic matter, the latter as evidenced by empirical data from forest stands in Europe. The ability of this version of MAGIC 7 to simulate and predict inorganic N concentrations in runoff is evaluated by means of data from whole-ecosystem manipulation experiments at Aber, Wales, UK, (nitrogen addition as part of the NITREX project) and Risdalsheia, Norway (exclusion of acid deposition as part of the RAIN project and climate change as part of the CLIMEX project). MAGIC 7 simulated the changes in N leaching satisfactorily as well as changes in base cations and acid neutralising capacity observed at these two sites. MAGIC 7 offers a potential tool for regional assessments and scenario studies of the combined effects of acid deposition, land-use and climate change.

scholarly journals Arctic charr (Salvelinus alpinus) re-established in a formerly acidified and highly dilute mountain lake under declining acidic deposition

2018 ◽  
Vol 38 ◽  
pp. 30-36
Author(s):  
Trygve Hesthagen ◽  
Randi Saksgård
Keyword(s):  
Water Quality ◽  
Calcium Concentration ◽  
Acidic Deposition ◽  
Salvelinus Alpinus ◽  
Arctic Charr ◽  
Age Groups ◽  
Mountain Lake ◽  
Dense Population ◽  
Acid Neutralising Capacity ◽  
Southern Norway

Arctic charr in Lake Ronvatn, a mountain lake in southern Norway was re-established through stocking. The population went extinction during the early 1980s due to acidification, when the lake was highly acidified with a mean pH of 5.2-5.4 with occasional declines to 4.3-4.7. However, from the mid to late 1990s, the pH and acid-neutralising capacity (ANC) of the lake rose to 5.8-5.9 and 13-15 µeq L-1, respectively. The lake is extremely dilute with a mean conductivity and calcium concentration of 7.7 µS cm-1 and 0.35 mg L-1, respectively. The lake was stocked with 250 Arctic charr from a neighbouring lake between 1998 and 2000. These introductions were highly successful, as test-fishing in 2004, 2008 and 2012 revealed a relatively dense population of Arctic charr, and the presence of several young age groups. Water quality has remained stable since the late 1990s, or has slightly improved.

scholarly journals Land use influences on acidification and recovery of freshwaters in Galloway, south-west Scotland

2001 ◽  
Vol 5 (3) ◽  
pp. 451-458 ◽  
Author(s):  
R. C. Helliwell ◽  
R. C. Ferrier ◽  
L. Johnston ◽  
J. Goodwin ◽  
R. Doughty
Keyword(s):  
Surface Waters ◽  
Chemical Recovery ◽  
Dry Period ◽  
Sulphur Deposition ◽  
South West ◽  
Recovery From Acidification ◽  
Long Term Trends ◽  
Acid Status ◽  
Annual Discharge

Abstract. The long term response of surface waters to changes in sulphur deposition and afforestation is investigated for three upland river systems in the Galloway region of south-west Scotland. From 1984-1999, these rivers exhibited a statistically significant decline in non-marine sulphate concentrations in response to reduced acid deposition. This reduction in non-marine sulphate was, however, insufficient to induce a pH recovery over the period. A statistically significant increase in river pH was observed between 1956-1970 (0.05 yr-1) when subsidised agricultural lime payments were at a maximum. In 1976, this subsidy ceased and surface waters have progressively acidified. In addition, climatic change is found to influence long-term trends in pH. Mean annual pH was greatest during a dry period between 1969-1973 when total annual discharge was low. Thereafter, pH declined gradually in response to higher rainfall and increased total annual discharge. Overall, surface waters draining the afforested catchments of the Rivers Cree and Bladnoch are more acid than those draining the moorland catchment of the Luce. These results indicate that in afforested catchments, current reductions in sulphur emissions have not led to an observed improvement in the acid status of surface waters. Forestry, therefore, represents a confounding factor with regard to chemical recovery from acidification in this region. Keywords: acidification, afforestation, deposition, rivers, lochs, non-marine sulphate, pH

scholarly journals Nitrogen Risk Assessment Model for Scotland: II. Hydrological transport and model testing

2004 ◽  
Vol 8 (2) ◽  
pp. 205-219 ◽  
Author(s):  
S. M. Dunn ◽  
A. Lilly ◽  
J. DeGroote ◽  
A. J. A. Vinten
Keyword(s):  
Risk Assessment ◽  
Transport Model ◽  
Meteorological Data ◽  
Preceding Paper ◽  
Assessment Model ◽  
Balance Model ◽  
N Leaching ◽  
Risk Assessment Model ◽  
National Scale ◽  
Catchment Scale

Abstract. The amount and concentration of N in catchment runoff is strongly controlled by a number of hydrological influences, such as leaching rates and the rate of transport of N from the land to surface water bodies. This paper describes how the principal hydrological controls at a catchment scale have been represented within the Nitrogen Risk Assessment Model for Scotland (NIRAMS); it demonstrates their influence through application of the model to eight Scottish catchments, contrasting in terms of their land use, climate and topography. Calculation of N leaching rates, described in the preceding paper (Dunn et al., 2004), is based on soil water content determined by application of a weekly water balance model. This model uses national scale datasets and has been developed and applied to the whole of Scotland using five years of historical meteorological data. A catchment scale transport model, constructed from a 50m digital elevation model, routes flows of N through the sub-surface and groundwater to the stream system. The results of the simulations carried out for eight different catchments demonstrate that the NIRAMS model is capable of predicting time-series of weekly stream flows and N concentrations, to an acceptable degree of accuracy. The model provides an appropriate framework for risk assessment applications requiring predictions in ungauged catchments and at a national scale. Analysis of the model behaviour shows that streamwater N concentrations are controlled both by the rate of supply of N from leaching as well as the rate of transport of N from the land to the water. Keywords: nitrogen, diffuse pollution, hydrology, model, transport, catchment

RAIN Project: Results after 8 Years of Experimentally Reduced Acid Deposition to a Whole Catchment

1993 ◽  
Vol 50 (2) ◽  
pp. 258-268 ◽  
Author(s):  
Richard F. Wright ◽  
Erik Lotse ◽  
Arne Semb
Keyword(s):  
Acid Deposition ◽  
Soil Chemistry ◽  
Nitrogen Saturation ◽  
Base Cations ◽  
Strong Acid ◽  
Catchment Scale ◽  
Exclusion Experiment ◽  
Surface Water Chemistry ◽  
Southern Norway

At Risdalsheia (southern Norway), an ongoing catchment-scale acid-exclusion experiment has been conducted since 1984 as part of the RAIN project (Reversing Acidification In Norway). Acid precipitation is collected on a 1200-m2 transparent roof, treated by ion exchange, sea salts readded, and reapplied as clean rain beneath the roof Up to 1990 annual surveys of soil chemistry have revealed no significant trends. The chemical composition of runoff has changed: sulfate decreased from about 111 μeq/L in 1984 to 38 μeq/L in 1992 and nitrate from about 33 to 5 μeq/L. Base cations decreased and alkalinity increased over the 8-yr period from −88 to −29 μeq/L to compensate for this change in strong acid anions. Much of the alkalinity change is due to the increased role of organic anions. The results fit an empirical nomograph relating alkalinity, base cations, and strong acid anions and a new empirical nomograph relating alkalinity, H+, and total organic carbon. The acid-exclusion experiment provides the first catchment-scale evidence for the reversibility of nitrogen saturation; RAIN results corroborate field observations of changes in surface water chemistry in response to reduced acid deposition as well as process-oriented, conceptual acidification models.

scholarly journals Winter climate affects long-term trends in stream water nitrate in acid-sensitive catchments in southern Norway

2007 ◽  
Vol 4 (5) ◽  
pp. 3055-3085 ◽  
Author(s):  
H. A. de Wit ◽  
A. Hindar ◽  
L. Hole
Keyword(s):  
Snow Depth ◽  
Stream Water ◽  
N Deposition ◽  
Climatic Changes ◽  
N Leaching ◽  
Forested Catchments ◽  
Discharge Temperature ◽  
Long Term Trends ◽  
Southern Norway

Abstract. Controls of stream water NO3 in mountainous and forested catchments are not thoroughly understood. Long-term trends in stream water NO3 are positive, neutral and negative, often apparently independent of trends in N deposition. Here, time series of NO3 in four small acid-sensitive catchments in southern Norway were analysed in order to identify likely drivers of long-term changes in NO3. In two sites, stream water NO3 export declined ca 50% over a period of 25 years while in the other sites NO3 export increased with roughly 20%. Discharge and N deposition alone were poor predictors of these trends. The most distinct trends in NO3 were found in winter and spring. Empirical models explained between 45% and 61% of the variation in weekly concentrations of NO3, and described both upward and downward seasonal trends tolerably well. Key explaining variables were snow depth, discharge, temperature and N deposition. All catchments showed reductions in snow depth and increases in winter discharge. In two inland catchments, located in moderate N deposition areas, these climatic changes appeared to drive the distinct decreases in winter and spring concentrations and fluxes of NO3. In a coast-near mountainous catchment in a low N deposition area, these climatic changes appeared to have the opposite effect, i.e. lead to increases in especially winter NO3. This suggests that the effect of a reduced snow pack may result in both decreased and increased catchment N leaching depending on interactions with N deposition, soil temperature regime and winter discharge.

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