Novel Analytical Approaches for the Characterization of Natural Organic Matter in the Cryosphere and its Potential Impacts on Climate Change
Climate change is predicted to be the most pronounced in high latitude ecosystems, however very little is known about their vulnerability to the projected warmer temperatures. In particular, natural organic matter (NOM) in the high latitude cryosphere which includes dissolved organic matter (DOM) an...
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ftcanadathes:oai:collectionscanada.gc.ca:OTU.1807/43704 2023-05-15T13:49:55+02:00 Novel Analytical Approaches for the Characterization of Natural Organic Matter in the Cryosphere and its Potential Impacts on Climate Change Pautler, Brent Gregory Simpson, Myrna J. 2013-11 http://hdl.handle.net/1807/43704 en_ca eng http://hdl.handle.net/1807/43704 Organic Geochemistry NMR Spectroscopy Natural Organic Matter Cryosphere Paleoclimate Chromatography Isotope Geochemistry Biomarkers 0485 0486 0425 0996 Thesis 2013 ftcanadathes 2014-01-19T00:45:02Z Climate change is predicted to be the most pronounced in high latitude ecosystems, however very little is known about their vulnerability to the projected warmer temperatures. In particular, natural organic matter (NOM) in the high latitude cryosphere which includes dissolved organic matter (DOM) and cryoconite organic matter (COM) from glaciers and soil organic matter (SOM) in permafrost, is highly susceptible to climate change which may lead to severe consequences on both local and global carbon biogeochemical cycles. Examination of DOM in glacier ice by a novel 1H nuclear magnetic resonance (NMR) water suppression pulse sequence at its natural abundance revealed and quantified the composition and the organic constituents in ice samples from Antarctica. 1H NMR spectra of samples from several glaciers were acquired and compared to the dominant fluorescent DOM fraction. This comprehensive approach showed that glacier ice DOM was mainly composed of small, labile biomolecules associated with microbes. Examination of the organic debris found on glacier surfaces (COM) from both Arctic and Antarctic glaciers were determined to be derived from microbes. Samples from Arctic glaciers were more chemically heterogeneous with small inputs of plant-derived material detected after targeted extractions. Therefore the COM carbon composition was determined to be dependent on the local glacier environment, suggesting a site specific contribution to the carbon cycle. Finally, the distribution of extracted branched glycerol dialkyl glycerol tetraether (GDGT)microbial membrane lipids and the deuterium incorporation of plant-wax n-alkane biomarkers extracted from dated permafrost SOM (paleosols) were independently applied for Canadian Arctic climate reconstruction during the last glacial maximum. Overall, the branched GDGT based temperature reconstructions from the Arctic paleosols reconstruct higher temperatures, likely when bacterial activity was optimal. The deuterium composition of the C29 n-alkane plant lipids appears to integrate an average annual signal. Further analysis by both non-selective NMR spectroscopic and targeted biomarker techniques on these paleosol samples revealed that the major vegetative sources from this paleoecosystem originated from woody and non-woody angiosperms. This thesis demonstrates several novel analytical characterization techniques, along with the major sources and composition of NOM in the cryosphere while demonstrating its use in paleoclimate applications. Thesis Antarc* Antarctic Antarctica Arctic Climate change Ice permafrost Theses Canada/Thèses Canada (Library and Archives Canada) Antarctic Arctic |
institution |
Open Polar |
collection |
Theses Canada/Thèses Canada (Library and Archives Canada) |
op_collection_id |
ftcanadathes |
language |
English |
topic |
Organic Geochemistry NMR Spectroscopy Natural Organic Matter Cryosphere Paleoclimate Chromatography Isotope Geochemistry Biomarkers 0485 0486 0425 0996 |
spellingShingle |
Organic Geochemistry NMR Spectroscopy Natural Organic Matter Cryosphere Paleoclimate Chromatography Isotope Geochemistry Biomarkers 0485 0486 0425 0996 Pautler, Brent Gregory Novel Analytical Approaches for the Characterization of Natural Organic Matter in the Cryosphere and its Potential Impacts on Climate Change |
topic_facet |
Organic Geochemistry NMR Spectroscopy Natural Organic Matter Cryosphere Paleoclimate Chromatography Isotope Geochemistry Biomarkers 0485 0486 0425 0996 |
description |
Climate change is predicted to be the most pronounced in high latitude ecosystems, however very little is known about their vulnerability to the projected warmer temperatures. In particular, natural organic matter (NOM) in the high latitude cryosphere which includes dissolved organic matter (DOM) and cryoconite organic matter (COM) from glaciers and soil organic matter (SOM) in permafrost, is highly susceptible to climate change which may lead to severe consequences on both local and global carbon biogeochemical cycles. Examination of DOM in glacier ice by a novel 1H nuclear magnetic resonance (NMR) water suppression pulse sequence at its natural abundance revealed and quantified the composition and the organic constituents in ice samples from Antarctica. 1H NMR spectra of samples from several glaciers were acquired and compared to the dominant fluorescent DOM fraction. This comprehensive approach showed that glacier ice DOM was mainly composed of small, labile biomolecules associated with microbes. Examination of the organic debris found on glacier surfaces (COM) from both Arctic and Antarctic glaciers were determined to be derived from microbes. Samples from Arctic glaciers were more chemically heterogeneous with small inputs of plant-derived material detected after targeted extractions. Therefore the COM carbon composition was determined to be dependent on the local glacier environment, suggesting a site specific contribution to the carbon cycle. Finally, the distribution of extracted branched glycerol dialkyl glycerol tetraether (GDGT)microbial membrane lipids and the deuterium incorporation of plant-wax n-alkane biomarkers extracted from dated permafrost SOM (paleosols) were independently applied for Canadian Arctic climate reconstruction during the last glacial maximum. Overall, the branched GDGT based temperature reconstructions from the Arctic paleosols reconstruct higher temperatures, likely when bacterial activity was optimal. The deuterium composition of the C29 n-alkane plant lipids appears to integrate an average annual signal. Further analysis by both non-selective NMR spectroscopic and targeted biomarker techniques on these paleosol samples revealed that the major vegetative sources from this paleoecosystem originated from woody and non-woody angiosperms. This thesis demonstrates several novel analytical characterization techniques, along with the major sources and composition of NOM in the cryosphere while demonstrating its use in paleoclimate applications. |
author2 |
Simpson, Myrna J. |
format |
Thesis |
author |
Pautler, Brent Gregory |
author_facet |
Pautler, Brent Gregory |
author_sort |
Pautler, Brent Gregory |
title |
Novel Analytical Approaches for the Characterization of Natural Organic Matter in the Cryosphere and its Potential Impacts on Climate Change |
title_short |
Novel Analytical Approaches for the Characterization of Natural Organic Matter in the Cryosphere and its Potential Impacts on Climate Change |
title_full |
Novel Analytical Approaches for the Characterization of Natural Organic Matter in the Cryosphere and its Potential Impacts on Climate Change |
title_fullStr |
Novel Analytical Approaches for the Characterization of Natural Organic Matter in the Cryosphere and its Potential Impacts on Climate Change |
title_full_unstemmed |
Novel Analytical Approaches for the Characterization of Natural Organic Matter in the Cryosphere and its Potential Impacts on Climate Change |
title_sort |
novel analytical approaches for the characterization of natural organic matter in the cryosphere and its potential impacts on climate change |
publishDate |
2013 |
url |
http://hdl.handle.net/1807/43704 |
geographic |
Antarctic Arctic |
geographic_facet |
Antarctic Arctic |
genre |
Antarc* Antarctic Antarctica Arctic Climate change Ice permafrost |
genre_facet |
Antarc* Antarctic Antarctica Arctic Climate change Ice permafrost |
op_relation |
http://hdl.handle.net/1807/43704 |
_version_ |
1766252511635701760 |