Comparisons of dissolved organic matter and its optical characteristics in small low and high Arctic catchments
Climate change is affecting the rate of carbon cycling, particularly in the Arctic. Permafrost degradation through deeper thaw and physical disturbances results in the release of carbon dioxide and methane to the atmosphere and to an increase in lateral dissolved organic matter (DOM) fluxes. Whereas...
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ftubpotsdam:oai:kobv.de-opus4-uni-potsdam:47789 2023-12-03T10:15:24+01:00 Comparisons of dissolved organic matter and its optical characteristics in small low and high Arctic catchments Coch, Caroline (Dr.) Juhls, Bennet Lamoureux, Scott F. Lafreniere, Melissa J. Fritz, Michael Heim, Birgit Lantuit, Hugues (Prof. Dr.) 2019-11-29 https://publishup.uni-potsdam.de/frontdoor/index/index/docId/47789 https://doi.org/10.5194/bg-16-4535-2019 eng eng https://publishup.uni-potsdam.de/frontdoor/index/index/docId/47789 https://doi.org/10.5194/bg-16-4535-2019 info:eu-repo/semantics/closedAccess ddc:550 Institut für Geowissenschaften article doc-type:article 2019 ftubpotsdam https://doi.org/10.5194/bg-16-4535-2019 2023-11-05T23:35:04Z Climate change is affecting the rate of carbon cycling, particularly in the Arctic. Permafrost degradation through deeper thaw and physical disturbances results in the release of carbon dioxide and methane to the atmosphere and to an increase in lateral dissolved organic matter (DOM) fluxes. Whereas riverine DOM fluxes of the large Arctic rivers are well assessed, knowledge is limited with regard to small catchments that cover more than 40% of the Arctic drainage basin. Here, we use absorption measurements to characterize changes in DOM quantity and quality in a low Arctic (Herschel Island, Yukon, Canada) and a high Arctic (Cape Bounty, Melville Island, Nunavut, Canada) setting with regard to geographical differences, impacts of permafrost degradation, and rainfall events. We find that DOM quantity and quality is controlled by differences in vegetation cover and soil organic carbon content (SOCC). The low Arctic site has higher SOCC and greater abundance of plant material resulting in higher chromophoric dissolved organic matter (cDOM) and dissolved organic carbon (DOC) than in the high Arctic. DOC concentration and cDOM in surface waters at both sites show strong linear relationships similar to the one for the great Arctic rivers. We used the optical characteristics of DOM such as cDOM absorption, specific ultraviolet absorbance (SUVA), ultraviolet (UV) spectral slopes (S275-295), and slope ratio (SR) for assessing quality changes downstream, at base flow and storm flow conditions, and in relation to permafrost disturbance. DOM in streams at both sites demonstrated optical signatures indicative of photodegradation downstream processes, even over short distances of 2000 m. Flow pathways and the connected hydrological residence time control DOM quality. Deeper flow pathways allow the export of permafrost-derived DOM (i.e. from deeper in the active layer), whereas shallow pathways with shorter residence times lead to the export of fresh surface- and near-surface-derived DOM. Compared to the large Arctic rivers, ... Article in Journal/Newspaper Arctic Cape Arctic Climate change Herschel Herschel Island Nunavut permafrost Melville Island Yukon University of Potsdam: publish.UP Arctic Nunavut Yukon Canada Herschel Island ENVELOPE(-139.089,-139.089,69.583,69.583) Cape Bounty ENVELOPE(-109.542,-109.542,74.863,74.863) Biogeosciences 16 23 4535 4553 |
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Open Polar |
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University of Potsdam: publish.UP |
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ftubpotsdam |
language |
English |
topic |
ddc:550 Institut für Geowissenschaften |
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ddc:550 Institut für Geowissenschaften Coch, Caroline (Dr.) Juhls, Bennet Lamoureux, Scott F. Lafreniere, Melissa J. Fritz, Michael Heim, Birgit Lantuit, Hugues (Prof. Dr.) Comparisons of dissolved organic matter and its optical characteristics in small low and high Arctic catchments |
topic_facet |
ddc:550 Institut für Geowissenschaften |
description |
Climate change is affecting the rate of carbon cycling, particularly in the Arctic. Permafrost degradation through deeper thaw and physical disturbances results in the release of carbon dioxide and methane to the atmosphere and to an increase in lateral dissolved organic matter (DOM) fluxes. Whereas riverine DOM fluxes of the large Arctic rivers are well assessed, knowledge is limited with regard to small catchments that cover more than 40% of the Arctic drainage basin. Here, we use absorption measurements to characterize changes in DOM quantity and quality in a low Arctic (Herschel Island, Yukon, Canada) and a high Arctic (Cape Bounty, Melville Island, Nunavut, Canada) setting with regard to geographical differences, impacts of permafrost degradation, and rainfall events. We find that DOM quantity and quality is controlled by differences in vegetation cover and soil organic carbon content (SOCC). The low Arctic site has higher SOCC and greater abundance of plant material resulting in higher chromophoric dissolved organic matter (cDOM) and dissolved organic carbon (DOC) than in the high Arctic. DOC concentration and cDOM in surface waters at both sites show strong linear relationships similar to the one for the great Arctic rivers. We used the optical characteristics of DOM such as cDOM absorption, specific ultraviolet absorbance (SUVA), ultraviolet (UV) spectral slopes (S275-295), and slope ratio (SR) for assessing quality changes downstream, at base flow and storm flow conditions, and in relation to permafrost disturbance. DOM in streams at both sites demonstrated optical signatures indicative of photodegradation downstream processes, even over short distances of 2000 m. Flow pathways and the connected hydrological residence time control DOM quality. Deeper flow pathways allow the export of permafrost-derived DOM (i.e. from deeper in the active layer), whereas shallow pathways with shorter residence times lead to the export of fresh surface- and near-surface-derived DOM. Compared to the large Arctic rivers, ... |
format |
Article in Journal/Newspaper |
author |
Coch, Caroline (Dr.) Juhls, Bennet Lamoureux, Scott F. Lafreniere, Melissa J. Fritz, Michael Heim, Birgit Lantuit, Hugues (Prof. Dr.) |
author_facet |
Coch, Caroline (Dr.) Juhls, Bennet Lamoureux, Scott F. Lafreniere, Melissa J. Fritz, Michael Heim, Birgit Lantuit, Hugues (Prof. Dr.) |
author_sort |
Coch, Caroline (Dr.) |
title |
Comparisons of dissolved organic matter and its optical characteristics in small low and high Arctic catchments |
title_short |
Comparisons of dissolved organic matter and its optical characteristics in small low and high Arctic catchments |
title_full |
Comparisons of dissolved organic matter and its optical characteristics in small low and high Arctic catchments |
title_fullStr |
Comparisons of dissolved organic matter and its optical characteristics in small low and high Arctic catchments |
title_full_unstemmed |
Comparisons of dissolved organic matter and its optical characteristics in small low and high Arctic catchments |
title_sort |
comparisons of dissolved organic matter and its optical characteristics in small low and high arctic catchments |
publishDate |
2019 |
url |
https://publishup.uni-potsdam.de/frontdoor/index/index/docId/47789 https://doi.org/10.5194/bg-16-4535-2019 |
long_lat |
ENVELOPE(-139.089,-139.089,69.583,69.583) ENVELOPE(-109.542,-109.542,74.863,74.863) |
geographic |
Arctic Nunavut Yukon Canada Herschel Island Cape Bounty |
geographic_facet |
Arctic Nunavut Yukon Canada Herschel Island Cape Bounty |
genre |
Arctic Cape Arctic Climate change Herschel Herschel Island Nunavut permafrost Melville Island Yukon |
genre_facet |
Arctic Cape Arctic Climate change Herschel Herschel Island Nunavut permafrost Melville Island Yukon |
op_relation |
https://publishup.uni-potsdam.de/frontdoor/index/index/docId/47789 https://doi.org/10.5194/bg-16-4535-2019 |
op_rights |
info:eu-repo/semantics/closedAccess |
op_doi |
https://doi.org/10.5194/bg-16-4535-2019 |
container_title |
Biogeosciences |
container_volume |
16 |
container_issue |
23 |
container_start_page |
4535 |
op_container_end_page |
4553 |
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1784262315108990976 |