Acidification trends in Swedish lakes : an assessment of past water chemistry conditions using lake sediments
This thesis presents temporal perspectives of lake acidification in Sweden. Sediment records have been used to study timing, trends and causes of acidification, and two different techniques for assessing past lake-water acidity are presented. A new technique for pH prediction, based on near-infrared...
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Umeå universitet, Institutionen för ekologi, miljö och geovetenskap
1993
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ftumeauniv:oai:DiVA.org:umu-140821 2023-10-09T21:54:38+02:00 Acidification trends in Swedish lakes : an assessment of past water chemistry conditions using lake sediments Korsman, Tom 1993 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-140821 eng eng Umeå universitet, Institutionen för ekologi, miljö och geovetenskap Umeå : Umeå universitet http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-140821 urn:isbn:91-7174-838-5 info:eu-repo/semantics/openAccess Palaeolimnology acidification history alkalization acid deposition land-use lake sediments near infrared spectroscopy diatoms multivariate calibration Sweden Ecology Ekologi Doctoral thesis, comprehensive summary info:eu-repo/semantics/doctoralThesis text 1993 ftumeauniv 2023-09-22T13:49:53Z This thesis presents temporal perspectives of lake acidification in Sweden. Sediment records have been used to study timing, trends and causes of acidification, and two different techniques for assessing past lake-water acidity are presented. A new technique for pH prediction, based on near-infrared (NIR) spectroscopy of surface sediments, is developed. This study shows that there is a pH related fraction of lake sediments that can be recorded by NIR analysis. Relationships between NIR spectra of surface sediment samples and measured lake-water pH values, and between NIR spectra of sediment cores and historical pH values inferred by diatom analysis, are modelled by partial least squares regression. The prediction errors of the models are comparable to those obtained by modelling of diatom and lake-water pH data. By further development NIR spectroscopy can become useful for inferring past pH, as well as several other lake-water parameters, from sediment cores. Diatom-based predictive models, using multivariate calibration methods, are developed for inferences of lake-water pH, alkalinity and colour. These models are used to provide a regional assessment of recent lake acidification in the provinces of Västerbotten and Norrbotten, northern Sweden. The study shows that a pH decline has occurred in some southeastern lakes, but that most of the lakes have not faced significant changes in lake-water pH, alkalinity and colour. The inferred water chemistiy changes are discussed in relation to atmospheric deposition and land-use. In a study of eight acid-sensitive Swedish boreal-forest lakes a past-analogue approach is used to test whether contemporary expansion of conifers could cause lake acidification. Water chemistry changes associated with the natural pre-historic colonization and expansion of spruce in Sweden (≈3000 years B.P.), at times of background atmospheric acidity, are inferred to evaluate the acidification ability of spruce per se on surface waters. This study shows that under natural, unpolluted conditions ... Doctoral or Postdoctoral Thesis Northern Sweden Norrbotten Umeå University: Publications (DiVA) |
institution |
Open Polar |
collection |
Umeå University: Publications (DiVA) |
op_collection_id |
ftumeauniv |
language |
English |
topic |
Palaeolimnology acidification history alkalization acid deposition land-use lake sediments near infrared spectroscopy diatoms multivariate calibration Sweden Ecology Ekologi |
spellingShingle |
Palaeolimnology acidification history alkalization acid deposition land-use lake sediments near infrared spectroscopy diatoms multivariate calibration Sweden Ecology Ekologi Korsman, Tom Acidification trends in Swedish lakes : an assessment of past water chemistry conditions using lake sediments |
topic_facet |
Palaeolimnology acidification history alkalization acid deposition land-use lake sediments near infrared spectroscopy diatoms multivariate calibration Sweden Ecology Ekologi |
description |
This thesis presents temporal perspectives of lake acidification in Sweden. Sediment records have been used to study timing, trends and causes of acidification, and two different techniques for assessing past lake-water acidity are presented. A new technique for pH prediction, based on near-infrared (NIR) spectroscopy of surface sediments, is developed. This study shows that there is a pH related fraction of lake sediments that can be recorded by NIR analysis. Relationships between NIR spectra of surface sediment samples and measured lake-water pH values, and between NIR spectra of sediment cores and historical pH values inferred by diatom analysis, are modelled by partial least squares regression. The prediction errors of the models are comparable to those obtained by modelling of diatom and lake-water pH data. By further development NIR spectroscopy can become useful for inferring past pH, as well as several other lake-water parameters, from sediment cores. Diatom-based predictive models, using multivariate calibration methods, are developed for inferences of lake-water pH, alkalinity and colour. These models are used to provide a regional assessment of recent lake acidification in the provinces of Västerbotten and Norrbotten, northern Sweden. The study shows that a pH decline has occurred in some southeastern lakes, but that most of the lakes have not faced significant changes in lake-water pH, alkalinity and colour. The inferred water chemistiy changes are discussed in relation to atmospheric deposition and land-use. In a study of eight acid-sensitive Swedish boreal-forest lakes a past-analogue approach is used to test whether contemporary expansion of conifers could cause lake acidification. Water chemistry changes associated with the natural pre-historic colonization and expansion of spruce in Sweden (≈3000 years B.P.), at times of background atmospheric acidity, are inferred to evaluate the acidification ability of spruce per se on surface waters. This study shows that under natural, unpolluted conditions ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Korsman, Tom |
author_facet |
Korsman, Tom |
author_sort |
Korsman, Tom |
title |
Acidification trends in Swedish lakes : an assessment of past water chemistry conditions using lake sediments |
title_short |
Acidification trends in Swedish lakes : an assessment of past water chemistry conditions using lake sediments |
title_full |
Acidification trends in Swedish lakes : an assessment of past water chemistry conditions using lake sediments |
title_fullStr |
Acidification trends in Swedish lakes : an assessment of past water chemistry conditions using lake sediments |
title_full_unstemmed |
Acidification trends in Swedish lakes : an assessment of past water chemistry conditions using lake sediments |
title_sort |
acidification trends in swedish lakes : an assessment of past water chemistry conditions using lake sediments |
publisher |
Umeå universitet, Institutionen för ekologi, miljö och geovetenskap |
publishDate |
1993 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-140821 |
genre |
Northern Sweden Norrbotten |
genre_facet |
Northern Sweden Norrbotten |
op_relation |
http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-140821 urn:isbn:91-7174-838-5 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1779318308748656640 |