Long-Term Trends in Lake Water pH and Metal Concentrations Inferred from Diatoms and Chrysophytes in Three Lakes near Sudbury, Ontario

1992 ◽  
Vol 49 (S1) ◽  
pp. 17-24 ◽  
Author(s):  
Aruna S. Dixit ◽  
Sushil S. Dixit ◽  
John P. Smol
Keyword(s):  
Lake Water ◽  
Sediment Cores ◽  
Chemical Recovery ◽  
Metal Concentrations ◽  
Acid Lakes ◽  
Water Ph ◽  
Long Term Trends ◽  
The 1960S ◽  
Provincial Park

Diatom valves and chrysophyte scales were analyzed in sediment cores to assess historical (post-1860) and recent (since 1970) trends in lake water pH, total [Al], and [Ni] in Lumsden, George, and Acid lakes (Killarney Provincial Park, Ontario). Although acidification in Lumsden and Acid lakes started in the 1930s, rapid acidification only occurred since the 1960s. As lake water pH declined, inferred [Al] greatly increased causing the extirpation of the sport fisheries. In nearby George Lake, acidification started in the 1920s, and inferred lake water pH declined about 0.5 of a pH unit by 1960. The fish community in George Lake survived where the inferred acidification was less severe than Acid and Lumsden lakes. As in previous paleolimnological studies, chrysophytes generally indicate earlier and more marked acidification trajectories when compared with trends inferred from diatoms, probably because the vernal blooming and euplanktonic chrysophytes are tracking spring pH depressions. Although all three lakes have acidified and metal concentrations have increased during this century, our study provides evidence that these lakes, located as far as 60 km away from Sudbury, are showing signs of biological and chemical recovery as a result of recent reductions in SO2 emissions from the Sudbury smelters.

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

A Climatic Model of Solar Radiation and Temperature Change

1974 ◽  
Vol 4 (1) ◽  
pp. 25-38 ◽  
Author(s):  
Clayton H. Reitan
Keyword(s):  
Solar Radiation ◽  
Energy Budget ◽  
Temperature Data ◽  
Direct Solar Radiation ◽  
Response Ratio ◽  
Radiation Data ◽  
Long Term Trends ◽  
The 1960S ◽  
The Relationship

Mean monthly temperatures for the Northern Hemisphere were determined for the years 1955 through 1968 following the same procedures used by H. C. Willett and J. M. Mitchell, Jr., in their studies of long-term trends. It was found that the downward trend they reported starting in the 1940s continued, though interrupted, into the 1960s.The temperature data when combined with radiation data and other components of the hemispheric energy budget led to the formulation of the response ratio, the relationship between change in incoming solar radiation and change in temperature. When this response ratio was applied to the reported trends in direct solar radiation and to the decrease in direct solar radiation following the eruption of Agung in 1963, a probable cause-effect relationship was suggested.

Long Term Trends in Mass Support for European Unification

1977 ◽  
Vol 12 (2) ◽  
pp. 150-177 ◽  
Author(s):  
Ronald Inglehart
Keyword(s):  
Active Role ◽  
The Political ◽  
Political Integration ◽  
Political Skills ◽  
Long Term Trends ◽  
Silent Revolution ◽  
The 1960S ◽  
Western Politics ◽  
Political Decisions

BENEATH THE ACTIVISM OF THE 1960s AND THE SEEMING QUIESCENCE of the 1970s a silent revolution has been occurring which is changing the infrastructure of Western politics in two ways: first, the values of Western publics have been shifting from an almost exclusive emphasis on material and physical security toward greater concern with intangible aspects of life; and secondly, there has been an increase in the political skills of Western publics that enables them to play a more active role in making important political decisions. Both processes tend to broaden the political horizons of these people and have important implications for supranational political integration.

Analysis of Long-Term Trends in Lake Water Quality Observations

2012 ◽  
Vol 12 (1) ◽  
pp. 231-238 ◽  
Author(s):  
Eung Seok Kim ◽  
Jo Hee Yoon ◽  
Jae Woon Lee ◽  
Hyun Il Choi
Keyword(s):  
Water Quality ◽  
Lake Water ◽  
Lake Water Quality ◽  
Long Term Trends

Historical Writing in Poland, Czechoslovakia, and Hungary

2018 ◽  
Author(s):  
Maciej Górny
Keyword(s):  
Historical Writing ◽  
East Central Europe ◽  
East Central ◽  
Central European ◽  
Considerable Impact ◽  
Long Term Trends ◽  
Post War ◽  
Control Education ◽  
The 1960S

This chapter focuses on historical writing in three central European states—Poland, Hungary, and Czechoslovakia. It looks at the long-term trends and phenomena in historical writing in the region. The first is the coexistence during the immediate post-war years of communist policy, together with more or less nationalistic historical interpretations. The next stage is typified by attempts to control education and research, and to reshape the organizational structure of historiography. An output of both of these phenomena was the ‘final’ or mature Marxist interpretations of Polish, Hungarian, Czech, and Slovak history. The next regional stage to have a considerable impact on the region’s historiography is the ‘golden age’ of the 1960s, when most of the innovative and influential books were published, and historians from East Central Europe came into closer contact with their colleagues from the western part of the continent.

scholarly journals Worldwide lake level trends and responses to background climate variation

2020 ◽  
Vol 24 (5) ◽  
pp. 2593-2608 ◽  
Author(s):  
Benjamin M. Kraemer ◽  
Anton Seimon ◽  
Rita Adrian ◽  
Peter B. McIntyre
Keyword(s):  
Water Level ◽  
Lake Water ◽  
Environmental Changes ◽  
Southern Oscillation ◽  
Climate Variation ◽  
Water Levels ◽  
P Value ◽  
Long Term Trends ◽  
Background Climate

Abstract. Lakes provide many important benefits to society, including drinking water, flood attenuation, nutrition, and recreation. Anthropogenic environmental changes may affect these benefits by altering lake water levels. However, background climate oscillations such as the El Niño–Southern Oscillation and the North Atlantic Oscillation can obscure long-term trends in water levels, creating uncertainty over the strength and ubiquity of anthropogenic effects on lakes. Here we account for the effects of background climate variation and test for long-term (1992–2019) trends in water levels in 200 globally distributed large lakes using satellite altimetry data. The median percentage of water level variation associated with background climate variation was 58 %, with an additional 10 % explained by seasonal variation and 25 % by the long-term trend. The relative influence of specific axes of background climate variation on water levels varied substantially across and within regions. After removing the effects of background climate variation on water levels, long-term water level trend estimates were lower (median: +0.8 cm yr−1) than calculated from raw water level data (median: +1.2 cm yr−1). However, the trends became more statistically significant in 86 % of lakes after removing the effects of background climate variation (the median p value of trends changed from 0.16 to 0.02). Thus, robust tests for long-term trends in lake water levels which may or may not be anthropogenic will require prior isolation and removal of the effects of background climate variation. Our findings suggest that background climate variation often masks long-term trends in environmental variables but can be accounted for through more comprehensive statistical analyses.

How Much Acidification Has Occurred in Adirondack Region Lakes (New York, USA) since Preindustrial Times?

1992 ◽  
Vol 49 (1) ◽  
pp. 128-141 ◽  
Author(s):  
B. F. Cumming ◽  
J. P. Smol ◽  
J. C. Kingston ◽  
D. F. Charles ◽  
H. J. B. Birks ◽  
...  
Keyword(s):  
New York ◽  
Lake Water ◽  
Sediment Cores ◽  
Target Population ◽  
Acid Neutralizing Capacity ◽  
Lake Water Chemistry ◽  
Neutralizing Capacity ◽  
Average Rainfall ◽  
Water Ph ◽  
Adirondack Lakes

Preindustrial and present-day lake water pH, acid neutralizing capacity (ANC), total monomeric aluminum (Alm), and dissolved organic carbon (DOC) were inferred from the species composition of diatom and chrysophyte microfossils in the tops (present-day inferences) and bottoms (pre-1850 inferences) of sediment cores collected from a statistically selected set of Adirondack lakes. Results from the study lakes were extrapolated to a predefined target population of 675 low-alkalinity Adirondack region lakes. Estimates of preindustrial to present-day changes in lake water chemistry show that approximately 25–35% of the target population has acidified. The magnitude of acidification was greatest in the low-alkalinity lakes of the southwestern Adirondacks, an area with little geological ability to neutralize acidic deposition and receives the highest annual average rainfall in the region. We estimate that ~80% of the target population lakes with present-day measured pH [Formula: see text] and 30–45% of lakes with pH between 5.2 and 6.0 have undergone large declines in pH and ANC, and concomitant increases in [Alm]. Estimated changes in [DOC] were small and show no consistent pattern in the acidified lakes. This study provides the first statistically based regional evaluation of the extent of lake acidification in the Adirondacks.

Intergenerational Social Mobility in Twentieth-Century Spain

2020 ◽  
pp. 224-250
Author(s):  
Carlos J. Gil-Hernández ◽  
Fabrizio Bernardi ◽  
Ruud Luijkx
Keyword(s):  
Twentieth Century ◽  
Structural Changes ◽  
Educational Expansion ◽  
Class Mobility ◽  
Political Modernization ◽  
Long Term Trends ◽  
Modernization Process ◽  
The 1960S ◽  
Social Fluidity

This chapter studies long-term trends in intergenerational class mobility in Spain across the twentieth century drawing from a large pooled dataset (n = 81,475). From the 1960s, Spain underwent a late but intense economic, cultural, and political modernization process. During this period of far-reaching institutional change, men and women experienced a significant increase in upward mobility rates and social fluidity: steady and substantial for women, more modest for men. We disentangle different pathways driving this change in social fluidity using counterfactual simulations. The main drivers of the observed equalization of opportunities were the educational expansion and the direct effect of social origins. We argue that women were particularly benefited from dramatic structural changes in labor force participation, occupational upgrading, and educational expansion in which more room at the top allowed disadvantaged social classes to depart from their origins.

Diatom-inferred pH calibration of lakes near Wawa, Ontario

1986 ◽  
Vol 64 (6) ◽  
pp. 1129-1133 ◽  
Author(s):  
Sushil S. Dixit
Keyword(s):  
Multiple Regression ◽  
Surface Sediment ◽  
Lake Water ◽  
Ph Indicator ◽  
Lake Region ◽  
Water Ph ◽  
Sedimentary Diatoms ◽  
Inferred Ph ◽  
Ph Calibration

In the absence of long-term pH records for lakes, sedimentary diatoms have often been used to detect the extent of recent lake acidification. Although various methods have been used to relate surface-sediment diatom remains to contemporary lake-water pH, their usefulness and selection criteria have not been clearly defined for Canadian lakes. Surface-sediment diatoms of 28 lakes (pH 4.0–8.13) located northeast of Lake Superior were identified and enumerated. Lake-water pH estimates were made using multiple regression analyses of selected diatom taxa and Hustedt's pH indicator groups, as well as by index α and index B. Multiple regression, using the abundance of pH indicator assemblages, appears to be the most suitable method for the studied lake region. Discrepancies associated with other methods are discussed in details.

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