Permafrost Landscape History Shapes Fluvial Chemistry, Ecosystem Carbon Balance, and Potential Trajectories of Future Change
Intensifying permafrost thaw alters carbon cycling by mobilizing large amounts of terrestrial substrate into aquatic ecosystems. Yet, few studies have measured aquatic carbon fluxes and constrained drivers of ecosystem carbon balance across heterogeneous Arctic landscapes. Here, we characterized hyd...
Published in: | Global Biogeochemical Cycles |
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Online Access: | http://www.osti.gov/servlets/purl/1885712 https://www.osti.gov/biblio/1885712 https://doi.org/10.1029/2022gb007403 |
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ftosti:oai:osti.gov:1885712 2023-07-30T04:01:34+02:00 Permafrost Landscape History Shapes Fluvial Chemistry, Ecosystem Carbon Balance, and Potential Trajectories of Future Change Zolkos, Scott Tank, Suzanne E. Kokelj, Steven V. Striegl, Robert G. Shakil, Sarah Voigt, Carolina Sonnentag, Oliver Quinton, William L. Schuur, Edward A.G. Zona, Donatella Lafleur, Peter M. Sullivan, Ryan C. Ueyama, Masahito Billesbach, David Cook, David Humphreys, Elyn R. Marsh, Philip 2023-03-13 application/pdf http://www.osti.gov/servlets/purl/1885712 https://www.osti.gov/biblio/1885712 https://doi.org/10.1029/2022gb007403 unknown http://www.osti.gov/servlets/purl/1885712 https://www.osti.gov/biblio/1885712 https://doi.org/10.1029/2022gb007403 doi:10.1029/2022gb007403 54 ENVIRONMENTAL SCIENCES 2023 ftosti https://doi.org/10.1029/2022gb007403 2023-07-11T10:14:40Z Intensifying permafrost thaw alters carbon cycling by mobilizing large amounts of terrestrial substrate into aquatic ecosystems. Yet, few studies have measured aquatic carbon fluxes and constrained drivers of ecosystem carbon balance across heterogeneous Arctic landscapes. Here, we characterized hydrochemical and landscape controls on fluvial carbon cycling, quantified fluvial carbon fluxes, and estimated fluvial contributions to ecosystem carbon balance across 33 watersheds in four ecoregions in the continuous permafrost zone of the western Canadian Arctic: unglaciated uplands, ice-rich moraine, and organic-rich lowlands and till plains. Major ions, stable isotopes, and carbon speciation and fluxes revealed patterns in carbon cycling across ecoregions defined by terrain relief and accumulation of organics. In previously unglaciated mountainous watersheds, bicarbonate dominated carbon export (70% of total) due to chemical weathering of bedrock. In lowland watersheds, where soil organic carbon stores were largest, lateral transport of dissolved organic carbon (50%) and efflux of biotic CO 2 (25%) dominated. In watersheds affected by thaw-induced mass wasting, erosion of ice-rich tills enhanced chemical weathering and increased particulate carbon fluxes by two orders of magnitude. From an ecosystem carbon balance perspective, fluvial carbon export in watersheds not affected by thaw-induced wasting was, on average, equivalent to 6–16% of estimated net ecosystem exchange (NEE). Finally, in watersheds affected by thaw-induced wasting, fluvial carbon export approached 60% of NEE. Because future intensification of thermokarst activity will amplify fluvial carbon export, determining the fate of carbon across diverse northern landscapes is a priority for constraining trajectories of permafrost region ecosystem carbon balance. Other/Unknown Material Arctic Ice permafrost Thermokarst SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) Arctic Global Biogeochemical Cycles 36 9 |
institution |
Open Polar |
collection |
SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) |
op_collection_id |
ftosti |
language |
unknown |
topic |
54 ENVIRONMENTAL SCIENCES |
spellingShingle |
54 ENVIRONMENTAL SCIENCES Zolkos, Scott Tank, Suzanne E. Kokelj, Steven V. Striegl, Robert G. Shakil, Sarah Voigt, Carolina Sonnentag, Oliver Quinton, William L. Schuur, Edward A.G. Zona, Donatella Lafleur, Peter M. Sullivan, Ryan C. Ueyama, Masahito Billesbach, David Cook, David Humphreys, Elyn R. Marsh, Philip Permafrost Landscape History Shapes Fluvial Chemistry, Ecosystem Carbon Balance, and Potential Trajectories of Future Change |
topic_facet |
54 ENVIRONMENTAL SCIENCES |
description |
Intensifying permafrost thaw alters carbon cycling by mobilizing large amounts of terrestrial substrate into aquatic ecosystems. Yet, few studies have measured aquatic carbon fluxes and constrained drivers of ecosystem carbon balance across heterogeneous Arctic landscapes. Here, we characterized hydrochemical and landscape controls on fluvial carbon cycling, quantified fluvial carbon fluxes, and estimated fluvial contributions to ecosystem carbon balance across 33 watersheds in four ecoregions in the continuous permafrost zone of the western Canadian Arctic: unglaciated uplands, ice-rich moraine, and organic-rich lowlands and till plains. Major ions, stable isotopes, and carbon speciation and fluxes revealed patterns in carbon cycling across ecoregions defined by terrain relief and accumulation of organics. In previously unglaciated mountainous watersheds, bicarbonate dominated carbon export (70% of total) due to chemical weathering of bedrock. In lowland watersheds, where soil organic carbon stores were largest, lateral transport of dissolved organic carbon (50%) and efflux of biotic CO 2 (25%) dominated. In watersheds affected by thaw-induced mass wasting, erosion of ice-rich tills enhanced chemical weathering and increased particulate carbon fluxes by two orders of magnitude. From an ecosystem carbon balance perspective, fluvial carbon export in watersheds not affected by thaw-induced wasting was, on average, equivalent to 6–16% of estimated net ecosystem exchange (NEE). Finally, in watersheds affected by thaw-induced wasting, fluvial carbon export approached 60% of NEE. Because future intensification of thermokarst activity will amplify fluvial carbon export, determining the fate of carbon across diverse northern landscapes is a priority for constraining trajectories of permafrost region ecosystem carbon balance. |
author |
Zolkos, Scott Tank, Suzanne E. Kokelj, Steven V. Striegl, Robert G. Shakil, Sarah Voigt, Carolina Sonnentag, Oliver Quinton, William L. Schuur, Edward A.G. Zona, Donatella Lafleur, Peter M. Sullivan, Ryan C. Ueyama, Masahito Billesbach, David Cook, David Humphreys, Elyn R. Marsh, Philip |
author_facet |
Zolkos, Scott Tank, Suzanne E. Kokelj, Steven V. Striegl, Robert G. Shakil, Sarah Voigt, Carolina Sonnentag, Oliver Quinton, William L. Schuur, Edward A.G. Zona, Donatella Lafleur, Peter M. Sullivan, Ryan C. Ueyama, Masahito Billesbach, David Cook, David Humphreys, Elyn R. Marsh, Philip |
author_sort |
Zolkos, Scott |
title |
Permafrost Landscape History Shapes Fluvial Chemistry, Ecosystem Carbon Balance, and Potential Trajectories of Future Change |
title_short |
Permafrost Landscape History Shapes Fluvial Chemistry, Ecosystem Carbon Balance, and Potential Trajectories of Future Change |
title_full |
Permafrost Landscape History Shapes Fluvial Chemistry, Ecosystem Carbon Balance, and Potential Trajectories of Future Change |
title_fullStr |
Permafrost Landscape History Shapes Fluvial Chemistry, Ecosystem Carbon Balance, and Potential Trajectories of Future Change |
title_full_unstemmed |
Permafrost Landscape History Shapes Fluvial Chemistry, Ecosystem Carbon Balance, and Potential Trajectories of Future Change |
title_sort |
permafrost landscape history shapes fluvial chemistry, ecosystem carbon balance, and potential trajectories of future change |
publishDate |
2023 |
url |
http://www.osti.gov/servlets/purl/1885712 https://www.osti.gov/biblio/1885712 https://doi.org/10.1029/2022gb007403 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Ice permafrost Thermokarst |
genre_facet |
Arctic Ice permafrost Thermokarst |
op_relation |
http://www.osti.gov/servlets/purl/1885712 https://www.osti.gov/biblio/1885712 https://doi.org/10.1029/2022gb007403 doi:10.1029/2022gb007403 |
op_doi |
https://doi.org/10.1029/2022gb007403 |
container_title |
Global Biogeochemical Cycles |
container_volume |
36 |
container_issue |
9 |
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1772812336790241280 |