Permafrost conditions in peatlands regulate magnitude, timing, and chemical composition of catchment dissolved organic carbon export
Abstract Permafrost thaw in peatlands has the potential to alter catchment export of dissolved organic carbon ( DOC ) and thus influence downstream aquatic C cycling. Subarctic peatlands are often mosaics of different peatland types, where permafrost conditions regulate the hydrological setting of e...
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crwiley:10.1111/gcb.12607 2024-10-06T13:52:06+00:00 Permafrost conditions in peatlands regulate magnitude, timing, and chemical composition of catchment dissolved organic carbon export Olefeldt, David Roulet, Nigel T. NSERC Sweden America Foundation Abisko Scientific Research Station Global Environmental and Climate Change Centre 2014 http://dx.doi.org/10.1111/gcb.12607 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fgcb.12607 https://onlinelibrary.wiley.com/doi/pdf/10.1111/gcb.12607 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Global Change Biology volume 20, issue 10, page 3122-3136 ISSN 1354-1013 1365-2486 journal-article 2014 crwiley https://doi.org/10.1111/gcb.12607 2024-09-11T04:14:52Z Abstract Permafrost thaw in peatlands has the potential to alter catchment export of dissolved organic carbon ( DOC ) and thus influence downstream aquatic C cycling. Subarctic peatlands are often mosaics of different peatland types, where permafrost conditions regulate the hydrological setting of each type. We show that hydrological setting is key to observed differences in magnitude, timing, and chemical composition of DOC export between permafrost and nonpermafrost peatland types, and that these differences influence the export of DOC of larger catchments even when peatlands are minor catchment components. In many aspects, DOC export from a studied peatland permafrost plateau was similar to that of a forested upland catchment. Similarities included low annual export (2–3 g C m −2 ) dominated by the snow melt period (~70%), and how substantial DOC export following storms required wet antecedent conditions. Conversely, nonpermafrost fens had higher DOC export (7 g C m −2 ), resulting from sustained hydrological connectivity during summer. Chemical composition of catchment DOC export arose from the mixing of highly aromatic DOC from organic soils from permafrost plateau soil water and upland forest surface horizons with nonaromatic DOC from mineral soil groundwater, but was further modulated by fens. Increasing aromaticity from fen inflow to outlet was substantial and depended on both water residence time and water temperature. The role of fens as catchment biogeochemical hotspots was further emphasized by their capacity for sulfate retention. As a result of fen characteristics, a 4% fen cover in a mixed catchment was responsible for 34% higher DOC export, 50% higher DOC concentrations and ~10% higher DOC aromaticity at the catchment outlet during summer compared to a nonpeatland upland catchment. Expansion of fens due to thaw thus has potential to influence landscape C cycling by increasing fen capacity to act as biogeochemical hotspots, amplifying aquatic C cycling, and increasing catchment DOC export. Article in Journal/Newspaper permafrost Subarctic Wiley Online Library Global Change Biology 20 10 3122 3136 |
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Wiley Online Library |
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English |
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Abstract Permafrost thaw in peatlands has the potential to alter catchment export of dissolved organic carbon ( DOC ) and thus influence downstream aquatic C cycling. Subarctic peatlands are often mosaics of different peatland types, where permafrost conditions regulate the hydrological setting of each type. We show that hydrological setting is key to observed differences in magnitude, timing, and chemical composition of DOC export between permafrost and nonpermafrost peatland types, and that these differences influence the export of DOC of larger catchments even when peatlands are minor catchment components. In many aspects, DOC export from a studied peatland permafrost plateau was similar to that of a forested upland catchment. Similarities included low annual export (2–3 g C m −2 ) dominated by the snow melt period (~70%), and how substantial DOC export following storms required wet antecedent conditions. Conversely, nonpermafrost fens had higher DOC export (7 g C m −2 ), resulting from sustained hydrological connectivity during summer. Chemical composition of catchment DOC export arose from the mixing of highly aromatic DOC from organic soils from permafrost plateau soil water and upland forest surface horizons with nonaromatic DOC from mineral soil groundwater, but was further modulated by fens. Increasing aromaticity from fen inflow to outlet was substantial and depended on both water residence time and water temperature. The role of fens as catchment biogeochemical hotspots was further emphasized by their capacity for sulfate retention. As a result of fen characteristics, a 4% fen cover in a mixed catchment was responsible for 34% higher DOC export, 50% higher DOC concentrations and ~10% higher DOC aromaticity at the catchment outlet during summer compared to a nonpeatland upland catchment. Expansion of fens due to thaw thus has potential to influence landscape C cycling by increasing fen capacity to act as biogeochemical hotspots, amplifying aquatic C cycling, and increasing catchment DOC export. |
author2 |
NSERC Sweden America Foundation Abisko Scientific Research Station Global Environmental and Climate Change Centre |
format |
Article in Journal/Newspaper |
author |
Olefeldt, David Roulet, Nigel T. |
spellingShingle |
Olefeldt, David Roulet, Nigel T. Permafrost conditions in peatlands regulate magnitude, timing, and chemical composition of catchment dissolved organic carbon export |
author_facet |
Olefeldt, David Roulet, Nigel T. |
author_sort |
Olefeldt, David |
title |
Permafrost conditions in peatlands regulate magnitude, timing, and chemical composition of catchment dissolved organic carbon export |
title_short |
Permafrost conditions in peatlands regulate magnitude, timing, and chemical composition of catchment dissolved organic carbon export |
title_full |
Permafrost conditions in peatlands regulate magnitude, timing, and chemical composition of catchment dissolved organic carbon export |
title_fullStr |
Permafrost conditions in peatlands regulate magnitude, timing, and chemical composition of catchment dissolved organic carbon export |
title_full_unstemmed |
Permafrost conditions in peatlands regulate magnitude, timing, and chemical composition of catchment dissolved organic carbon export |
title_sort |
permafrost conditions in peatlands regulate magnitude, timing, and chemical composition of catchment dissolved organic carbon export |
publisher |
Wiley |
publishDate |
2014 |
url |
http://dx.doi.org/10.1111/gcb.12607 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fgcb.12607 https://onlinelibrary.wiley.com/doi/pdf/10.1111/gcb.12607 |
genre |
permafrost Subarctic |
genre_facet |
permafrost Subarctic |
op_source |
Global Change Biology volume 20, issue 10, page 3122-3136 ISSN 1354-1013 1365-2486 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/gcb.12607 |
container_title |
Global Change Biology |
container_volume |
20 |
container_issue |
10 |
container_start_page |
3122 |
op_container_end_page |
3136 |
_version_ |
1812180427481284608 |