scholarly journals Acid deposition and lake chemistry in southwest China

1994 ◽  
Vol 75 (1-2) ◽  
pp. 61-78 ◽  
Author(s):  
H. B. Xue ◽  
J. L. Schnoor
Keyword(s):  
Acid Deposition ◽  
Southwest China ◽  
Lake Chemistry

Water chemistry and dissolved organic carbon trends in lakes from Canada’s Atlantic Provinces: no recovery from acidification measured after 25 years of lake monitoring

2011 ◽  
Vol 68 (4) ◽  
pp. 663-674 ◽  
Author(s):  
Thomas A. Clair ◽  
Ian F. Dennis ◽  
Robert Vet
Keyword(s):  
North America ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Acid Deposition ◽  
Base Cations ◽  
Sampling Period ◽  
Lake Chemistry ◽  
Neutralization Capacity ◽  
Air Temperatures ◽  
Recovery From Acidification

We analyzed chemistry trends for 66 Atlantic Canada lakes using data collected from 1983 to 2007, as well as from 1990 to 2007 and 2000 to 2007 for the original 66 and a further 25 lakes that were later added to the network. Though receiving the lowest acid deposition in eastern North America, the region’s waters are seriously affected by acid rain because of poorly buffering soils and bedrock. Earlier work had shown that despite large decreases in sulfate deposition, lake pH and calculated acid neutralization capacity (ANCc) had not increased as they had elsewhere in North America and Europe. Despite a 50% decrease in acid deposition, a further 10 years of lake chemistry data showed a regional increase in ANCc only at the beginning of the sampling period but no increase since the early 1990s. There were also no increases in pH and base cations in the region’s lakes. We show a regional increase in Gran titration ANC (ANCG) from 2000 to the present, which we ascribe to increases in dissolved organic carbon that is probably due to a regional increase in annual air temperatures.

Acid deposition and watershed characteristics in relation to lake chemistry in northeastern Minnesota

1985 ◽  
Vol 11 (5) ◽  
pp. 425-440 ◽  
Author(s):  
George Rapp ◽  
James D. Allert ◽  
Barbara W. Liukkonen ◽  
Judith A. Ilse ◽  
Orie L. Loucks ◽  
...  
Keyword(s):  
Acid Deposition ◽  
Lake Chemistry ◽  
Watershed Characteristics

scholarly journals Surface water acidification and critical loads: exploring the F-factor

2009 ◽  
Vol 13 (11) ◽  
pp. 2191-2201 ◽  
Author(s):  
L. Rapp ◽  
K. Bishop
Keyword(s):  
Time Series ◽  
Surface Water ◽  
Water Chemistry ◽  
Acid Deposition ◽  
Critical Loads ◽  
Base Cations ◽  
Recovery Phase ◽  
Biogeochemical Model ◽  
Lake Chemistry ◽  
F Factor

Abstract. As acid deposition decreases, uncertainties in methods for calculating critical loads become more important when judgements have to be made about whether or not further emission reductions are needed. An important aspect of one type of model that has been used to calculate surface water critical loads is the empirical F-factor which estimates the degree to which acid deposition is neutralised before it reaches a lake at any particular point in time relative to the pre-industrial, steady-state water chemistry conditions. In this paper we will examine how well the empirical F-functions are able to estimate pre-industrial lake chemistry as lake chemistry changes during different phases of acidification and recovery. To accomplish this, we use the dynamic, process-oriented biogeochemical model SAFE to generate a plausible time series of annual runoff chemistry for ca. 140 Swedish catchments between 1800 and 2100. These annual hydrochemistry data are then used to generate empirical F-factors that are compared to the "actual" F-factor seen in the SAFE data for each lake and year in the time series. The dynamics of the F-factor as catchments acidify, and then recover are not widely recognised. Our results suggest that the F-factor approach worked best during the acidification phase when soil processes buffer incoming acidity. However, the empirical functions for estimating F from contemporary lake chemistry are not well suited to the recovery phase when the F-factor turns negative due to recovery processes in the soil. This happens when acid deposition has depleted the soil store of BC, and then acid deposition declines, reducing the leaching of base cations to levels below those in the pre-industrial era. An estimate of critical load from water chemistry during recovery and empirical F functions would therefore result in critical loads that are too low. Therefore, the empirical estimates of the F-factor are a significant source of uncertainty in the estimate of surface water critical loads and related calculations for quantifying lake acidification status, especially now that acid deposition has declined across large areas of Europe and North America.

Acid Rain, Catchment Characteristics and Fishery Status

1983 ◽  
Vol 15 (12) ◽  
pp. 47-58
Author(s):  
P F Chester
Keyword(s):  
Acid Rain ◽  
Acid Deposition ◽  
Lake Chemistry ◽  
Catchment Characteristics ◽  
Water Composition ◽  
Fishery Status

In this paper data on lake chemistry and fishery status in the Sorlandet area of South Norway are examined for relationships between acid inputs, water composition and fishery status. The concept of the “effective reactivity” of a catchment is introduced to enable comparisons to be made between like lakes. It is found that the effective catchment reactivity is a much better predictor of fishery status than is acid input to these catchments. The factors underlying these relationships are discussed as is the possibility that acid deposition has changed the reactivity of these catchments in recent decades. Proposals are made for resolving some of the questions raised.

scholarly journals Surface water acidification and critical loads: exploring the F-factor

2009 ◽  
Vol 6 (3) ◽  
pp. 3917-3945
Author(s):  
L. Rapp ◽  
K. Bishop
Keyword(s):  
Time Series ◽  
Surface Water ◽  
Acid Deposition ◽  
Critical Loads ◽  
Recovery Phase ◽  
Annual Runoff ◽  
Biogeochemical Model ◽  
Lake Chemistry ◽  
Empirical Estimates ◽  
F Factor

Abstract. As acid deposition decreases, uncertainties in methods for calculating critical loads become more important when judgements have to be made about whether or not further emission reductions are needed. An important aspect of one type of model that has been used to calculate surface water critical loads is the empirical F-factor which estimates the degree to which acid deposition is neutralised before it reaches a lake at any particular point in time relative to the pre-industrial, steady-state water chemistry conditions. In this paper we will examine how well the empirical F-functions are able to estimate pre-industrial lake chemistry as lake chemistry changes during different phases of acidification and recovery. To accomplish this, we use the dynamic, process-oriented biogeochemical model SAFE to generate a plausible time series of annual runoff chemistry for ca 140 Swedish catchments between 1800 and 2100. These annual hydrochemistry data are then used to generate empirical F-factors that are compared to the "actual" F-factor seen in the SAFE data for each lake and year in the time series. The dynamics of the F-factor as catchments acidify, and then recover are not widely recognised. Our results suggest that the F-factor approach worked best during the acidification phase when soil processes buffer incoming acidity. However, the empirical functions for estimating F from contemporary lake chemistry are not well suited to the recovery phase when the F-factor turns negative due to recovery processes in the soil. Therefore, the empirical estimates of the F-factor are a significant source of uncertainty in the estimate of surface water critical loads and related calculations for quantifying lake acidification status, especially now that acid deposition has declined across large areas of Europe and North America.

scholarly journals Probable changes in lake chemistry in Canada’s Atlantic Provinces under proposed North American emission reductions

2003 ◽  
Vol 7 (4) ◽  
pp. 574-582 ◽  
Author(s):  
T. A. Clair ◽  
I. F. Dennis ◽  
B. J. Cosby
Keyword(s):  
Water Chemistry ◽  
Acid Deposition ◽  
Base Cations ◽  
Trend Detection ◽  
Atlantic Canada ◽  
Monitoring Networks ◽  
Initial Water ◽  
Lake Chemistry ◽  
Magic Model ◽  
The Government

Abstract. Atlantic Canada, located in the extreme north-eastern portion of North America, receives acid precipitation from all major acid emission sources on the eastern part of the continent. The region was glaciated and has thin soils over a generally poorly acid buffering bedrock. Because of regional topography, large groupings of lakes occur in a number of regions. Environment Canada and the Government of New Brunswick have operated lake sampling networks in trend detection studies and have concentrated their work on these lake groupings. The MAGIC model has been applied to these lakes and their catchments to see: a) what initial water chemistry conditions existed before acidification began, b) what the chemistry was like during the worst of regional acid deposition, and c) what it would be like under deposition conditions predicted for new Canadian and US emission reduction proposals. While pH, sulphate, acid neutralisation capacity (ANC) and the sum of the base cations (SBC) of all lakes have been significantly affected by acid deposition, water chemistry conditions are now considerably better than they were in 1975, at the worst of the deposition. However, a 50% reduction in acid deposition from Year 2000 deposition amounts will not return water chemistry to original conditions in most of the region. Keywords: Atlantic Canada, monitoring networks, acidification, predictions, MAGIC

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