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6 - Diatoms as indicators of surface-water acidity
- from Part II - Diatoms as indicators of environmental change in flowing waters and lakes
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- By Richard W. Battarbee, Department of Geography, UCL, Donald F. Charles, Patrick Center for Environmental Research, Christian Bigler, Umeå University, Brian F. Cumming, Queen's University, Ingemar Renberg, Umeå University
- Edited by John P. Smol, Queen's University, Ontario, Eugene F. Stoermer, University of Michigan, Ann Arbor
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- Book:
- The Diatoms
- Published online:
- 05 June 2012
- Print publication:
- 30 September 2010, pp 98-121
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Summary
Introduction
Lake acidification became an environmental issue of international significance in the late 1960s and early 1970s when Scandinavian scientists claimed that “acid rain” was the principal reason why fish populations had declined dramatically in Swedish and Norwegian lakes (Odén, 1968; Jensen & Snekvik, 1972; Almer et al., 1974). Similar claims were being made at about the same time in Canada (Beamish & Harvey, 1972). However, these claims were not immediately accepted by all scientists. It was argued by some that acidification was due to natural factors or to changes in catchment land use and management (Rosenqvist 1977, 1978; Krug & Frink, 1983; Pennington, 1984).
In the scientific debate that followed, diatom analysis played a pivotal role. It enabled the timing and extent of lake acidification to be reconstructed (Charles et al., 1989; Battarbee et al., 1990; Dixit et al., 1992a) and allowed the various competing hypotheses concerning the causes of lake acidification to be evaluated (Battarbee et al., 1985; Battarbee & Charles, 1994; Emmett et al., 1994). However, diatoms had been recognized and used as indicators of water pH well before the beginning of this controversy. The acid rain issue served to highlight the importance of diatoms and stimulated the advance of more robust and sophisticated techniques, especially the development of transfer functions for reconstructing lake-water pH and related hydrochemical variables.
This chapter outlines the history of diatoms as pH indicators, and describes how diatoms are currently used in studies of acid and acidified waters. It then describes how diatom-based paleolimnological methods have been used to trace the pH and acidification history of lakes and how diatoms are being used to monitor acidity trends in streams and lakes.
5 - Diatoms as indicators of surface water acidity
- Edited by E. F. Stoermer, University of Michigan, Ann Arbor, John P. Smol, Queen's University, Ontario
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- Book:
- The Diatoms
- Published online:
- 16 January 2010
- Print publication:
- 29 April 1999, pp 85-127
-
- Chapter
- Export citation
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Summary
Introduction
Lake acidification became an environmental issue of international significance in the late 1960s and early 1970s when Scandinavian scientists claimed that ‘acid rain’ was the principal reason why fish populations had declined dramatically in Swedish and Norwegian lakes (Odén, 1968; Jensen & Snekvik, 1972; Almer et al., 1974). Similar claims were being made at about the same time in Canada (Beamish & Harvey, 1972). However, these claims were not immediately accepted by all scientists. It was argued instead that acidification was due to natural factors or to changes in catchment land-use and management (Rosenqvist 1977, 1978; Pennington 1984; Krug & Frink, 1983).
In the scientific debate that followed, diatom analysis played a pivotal role. It enabled the timing and extent of lake acidification to be reconstructed (Charles et al., 1989; Battarbee et al., 1990; Dixit et al., 1992a) and allowed the various competing hypotheses concerning the causes of lake acidification to be evaluated (Battarbee et al., 1985; Battarbee & Charles 1994; Emmett et al., 1994). However, diatoms had been recognized and used as indicators of water pH well before the beginning of this controversy. The ‘acid rain’ issue served to highlight the importance of diatoms and stimulated the advance of more robust and sophisticated techniques, especially the development of transfer functions for reconstructing lakewater pH and related hydrochemical variables.
This chapter outlines the history of diatoms as pH indicators, and describes how diatoms are currently used in studies of acid and acidified waters.
An experimental and palaeoecological study of algal responses to lake acidification and liming in three central Swedish lakes
- N. JOHN ANDERSON, PETER BLOMQVIST, INGEMAR RENBERG
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- Journal:
- European Journal of Phycology / Volume 32 / Issue 1 / February 1997
- Published online by Cambridge University Press:
- 01 February 1997, pp. 35-48
- Print publication:
- February 1997
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Contemporary phytoplankton and palaeolimnological studies were made of the algal response to acidification and liming in three lakes in Hälsingland, central Sweden (Njupfatet, Sjösjön, Djuptjärn). Surveys and experimental studies of the phytoplankton response to liming were undertaken at Njupfatet, together with an experiment designed to determine the possible role of lake sediments as an inoculum for any new species arriving in the water column. Liming had little quantitative or qualitative effect on the phytoplankton diversity at Njupfatet, but did result in the loss of the dominant contributor to algal biomass, Merismopedia tenuissima. None of the four new species recorded in the lake following liming was hatched from the sediment inoculum experiment. A freeze core from Njupfatet was dated by 210Pb and carbonaceous fly-ash particle profiles were also determined for Njupfatet and Sjösjön, which provided an approximate chronology for the latter lake. Diatom analyses were made of the three lakes and pH and dissolved organic carbon inferred using weighted averaging methodology. Njupfatet had no planktonic diatoms over the last 200–300 years, and was dominated by benthic diatoms, but the diatom-inferred pH suggests that the lake was acidified to pH < 5 prior to liming in 1989. Both Djuptjärn and Sjösjön were dominated by planktonic diatoms, and were acidifying from (c. 1970) prior to liming, Sjösjön from pH 6 to ∼ 5 and Djuptjärn from 6·5 to ∼ 5·5. These pH inferences suggest that at least some lakes in this region are susceptible to atmospheric acidification. The response of the diatoms to liming is discussed, in particular the rapid expansion at Njupfatet, of Cyclotella glomerata a diatom which was also present in Sjösjön for a period prior to acidification, and at other lakes in south-west Sweden. Possible reasons for the expansion of this small centric diatom are discussed.
V - Palaeolimnological studies
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- By Ingemar Renberg, Department of Ecological Botany, University of Umeå, S-901 87 Umeå, Sweden, Richard W. Battarbee, Palaeoecology Research Unit, Department of Geography, University College London, 26 Bedford Way, London WC1H 0AP, U.K.
- Edited by B. J. Mason
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- Book:
- The Surface Waters Acidification Programme
- Published online:
- 05 February 2012
- Print publication:
- 21 February 1991, pp 281-326
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Summary
Physical, chemical and biological (microfossil) analyses of lake sediment cores enable lake, catchment and atmospheric histories to be reconstructed with high resolution over a range of timescales. In the SWAP Palaeolimnology Programme these techniques have been used to trace the recent (post 1800 A.D.) history of a number of specially selected study sites in Norway, Sweden and the U.K. For this purpose a large calibration data-set of diatoms and water chemistry has been assembled and new statistical techniques of pH reconstruction have been developed. In addition, by comparing temporal trends and spatial patterns within and between sites, various explanations for recent lake acidification have been evaluated.
Studies of complete post-glacial (10000 years) sediment sequences at a number of sites showed that long-term acidification has occurred at some sites but the rate of change before 1800 A.D. at all sites was zero or less than 0.1 pH unit per 1000 years. Tests of the ‘land-use change’ hypothesis involving studies of past analogues, sites with no decrease in grazing intensity, sites above the treeline and sites with minimal catchments all failed and tended instead to support the acid deposition hypothesis. The only observed land-use effect was an acceleration in the rate of acidification followed afforestation at a site in the Scottish Trossachs.