Molecular analysis of lake-sediment organic matter : long-term dynamics and environmental implications in boreal lakes
Lake sediment organic matter is material composed of residues from plants, algae, animals, fungi and bacteria. Its molecular composition is dependent on the sources as well as secondary biotic and abiotic transformations, which combined generates a highly complex matrix. Considering that organic mat...
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Umeå universitet, Institutionen för ekologi, miljö och geovetenskap
2023
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ftumeauniv:oai:DiVA.org:umu-213753 2023-10-09T21:56:10+02:00 Molecular analysis of lake-sediment organic matter : long-term dynamics and environmental implications in boreal lakes Molekylär analys av organiskt material i sjösediment : långtidsdynamik och miljöpåverkan i boreala sjöar. Ninnes, Sofia 2023 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-213753 eng eng Umeå universitet, Institutionen för ekologi, miljö och geovetenskap Umeå : Umeå University orcid:0000-0001-9659-2722 http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-213753 urn:isbn:978-91-8070-144-0 urn:isbn:978-91-8070-145-7 info:eu-repo/semantics/openAccess Lake sediment Holocene organic matter Pyrolysis-GC/MS mid-infrared spectroscopy boreal Environmental Sciences Miljövetenskap Doctoral thesis, comprehensive summary info:eu-repo/semantics/doctoralThesis text 2023 ftumeauniv 2023-09-22T14:01:05Z Lake sediment organic matter is material composed of residues from plants, algae, animals, fungi and bacteria. Its molecular composition is dependent on the sources as well as secondary biotic and abiotic transformations, which combined generates a highly complex matrix. Considering that organic matter plays a key role in carbon and nitrogen cycle, and its composition affects many different biogeochemical reactions, paleolimnologic studies have payed proportionately little attention to the organic matter composition compared with the other sediment fractions, even though organic matter makes up 20–60 % of the dry sediment mass in boreal and subarctic lakes. This thesis therefore primarily aims to explore and evaluate two methods; pyrolysis-gas chromatography/mass spectrometry (Pyrolysis-GC/MS) and diffuse reflectance Fourier-transform infrared spectroscopy (DRIFTS) for characterisation of bulk organic matter at the molecular level, both which have been extensively used for soils and peat and which balances the need for cost and time-effective analysis and for analytical detail. With pyrolysis-GC/MS the organic matter composition and long-term dynamics in two neighbouring boreal lakes is explored and compared with the conventional bulk carbon and nitrogen contents and their stable isotopes. Both pyrolysis data and conventional data capture the timing of organic matter compositional changes, but only pyrolysis provides detailed information on how the composition changes, which allows for a deeper understanding of the processes behind the changes. The same two lakes are also analysed with DRIFTS and with this approach information on the major organic compound groups aromatics, lignin, aliphatics, proteins and polysaccharides is extracted. In combination with the rapid analysis time and low cost, DRIFTS emerges as a very useful tool for rapid yet informative organic matter analysis. DRIFTS is then evaluated as a stand-alone tool for sediment characterisation in four mountain lakes. The four lakes all have different ... Doctoral or Postdoctoral Thesis Subarctic Umeå University: Publications (DiVA) Four Lakes ENVELOPE(-126.826,-126.826,54.858,54.858) |
institution |
Open Polar |
collection |
Umeå University: Publications (DiVA) |
op_collection_id |
ftumeauniv |
language |
English |
topic |
Lake sediment Holocene organic matter Pyrolysis-GC/MS mid-infrared spectroscopy boreal Environmental Sciences Miljövetenskap |
spellingShingle |
Lake sediment Holocene organic matter Pyrolysis-GC/MS mid-infrared spectroscopy boreal Environmental Sciences Miljövetenskap Ninnes, Sofia Molecular analysis of lake-sediment organic matter : long-term dynamics and environmental implications in boreal lakes |
topic_facet |
Lake sediment Holocene organic matter Pyrolysis-GC/MS mid-infrared spectroscopy boreal Environmental Sciences Miljövetenskap |
description |
Lake sediment organic matter is material composed of residues from plants, algae, animals, fungi and bacteria. Its molecular composition is dependent on the sources as well as secondary biotic and abiotic transformations, which combined generates a highly complex matrix. Considering that organic matter plays a key role in carbon and nitrogen cycle, and its composition affects many different biogeochemical reactions, paleolimnologic studies have payed proportionately little attention to the organic matter composition compared with the other sediment fractions, even though organic matter makes up 20–60 % of the dry sediment mass in boreal and subarctic lakes. This thesis therefore primarily aims to explore and evaluate two methods; pyrolysis-gas chromatography/mass spectrometry (Pyrolysis-GC/MS) and diffuse reflectance Fourier-transform infrared spectroscopy (DRIFTS) for characterisation of bulk organic matter at the molecular level, both which have been extensively used for soils and peat and which balances the need for cost and time-effective analysis and for analytical detail. With pyrolysis-GC/MS the organic matter composition and long-term dynamics in two neighbouring boreal lakes is explored and compared with the conventional bulk carbon and nitrogen contents and their stable isotopes. Both pyrolysis data and conventional data capture the timing of organic matter compositional changes, but only pyrolysis provides detailed information on how the composition changes, which allows for a deeper understanding of the processes behind the changes. The same two lakes are also analysed with DRIFTS and with this approach information on the major organic compound groups aromatics, lignin, aliphatics, proteins and polysaccharides is extracted. In combination with the rapid analysis time and low cost, DRIFTS emerges as a very useful tool for rapid yet informative organic matter analysis. DRIFTS is then evaluated as a stand-alone tool for sediment characterisation in four mountain lakes. The four lakes all have different ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Ninnes, Sofia |
author_facet |
Ninnes, Sofia |
author_sort |
Ninnes, Sofia |
title |
Molecular analysis of lake-sediment organic matter : long-term dynamics and environmental implications in boreal lakes |
title_short |
Molecular analysis of lake-sediment organic matter : long-term dynamics and environmental implications in boreal lakes |
title_full |
Molecular analysis of lake-sediment organic matter : long-term dynamics and environmental implications in boreal lakes |
title_fullStr |
Molecular analysis of lake-sediment organic matter : long-term dynamics and environmental implications in boreal lakes |
title_full_unstemmed |
Molecular analysis of lake-sediment organic matter : long-term dynamics and environmental implications in boreal lakes |
title_sort |
molecular analysis of lake-sediment organic matter : long-term dynamics and environmental implications in boreal lakes |
publisher |
Umeå universitet, Institutionen för ekologi, miljö och geovetenskap |
publishDate |
2023 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-213753 |
long_lat |
ENVELOPE(-126.826,-126.826,54.858,54.858) |
geographic |
Four Lakes |
geographic_facet |
Four Lakes |
genre |
Subarctic |
genre_facet |
Subarctic |
op_relation |
orcid:0000-0001-9659-2722 http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-213753 urn:isbn:978-91-8070-144-0 urn:isbn:978-91-8070-145-7 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1779320696229330944 |