Permafrost degradation and nitrogen cycling in Arctic rivers::insights from stable nitrogen isotope studies
Across the Arctic, vast areas of permafrost are being degraded by climate change, which has the potential to release substantial quantities of nutrients, including nitrogen into large Arctic rivers. These rivers heavily influence the biogeochemistry of the Arctic Ocean, so it is important to underst...
Published in: | Biogeosciences |
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2023
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Online Access: | https://pure.uhi.ac.uk/en/publications/1b3d40fd-efb8-41aa-b385-98ac9bf4ff52 https://doi.org/10.5194/bg-20-365-2023 https://pureadmin.uhi.ac.uk/ws/files/32982444/bg_20_365_2023.pdf https://bg.copernicus.org/articles/20/365/2023/ |
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ftuhipublicatio:oai:pure.atira.dk:publications/1b3d40fd-efb8-41aa-b385-98ac9bf4ff52 2024-05-19T07:33:14+00:00 Permafrost degradation and nitrogen cycling in Arctic rivers::insights from stable nitrogen isotope studies Francis, Adam Ganeshram, Raja S. Tuerena, Robyn E. Spencer, Robert G. M. Holmes, Robert M. Rogers, Jennifer A. Mahaffey, Claire 2023-01-24 application/pdf https://pure.uhi.ac.uk/en/publications/1b3d40fd-efb8-41aa-b385-98ac9bf4ff52 https://doi.org/10.5194/bg-20-365-2023 https://pureadmin.uhi.ac.uk/ws/files/32982444/bg_20_365_2023.pdf https://bg.copernicus.org/articles/20/365/2023/ eng eng https://pure.uhi.ac.uk/en/publications/1b3d40fd-efb8-41aa-b385-98ac9bf4ff52 info:eu-repo/semantics/openAccess Francis , A , Ganeshram , R S , Tuerena , R E , Spencer , R G M , Holmes , R M , Rogers , J A & Mahaffey , C 2023 , ' Permafrost degradation and nitrogen cycling in Arctic rivers: insights from stable nitrogen isotope studies ' , Biogeosciences , vol. 20 , no. 2 , pp. 365-382 . https://doi.org/10.5194/bg-20-365-2023 article 2023 ftuhipublicatio https://doi.org/10.5194/bg-20-365-2023 2024-05-02T00:07:13Z Across the Arctic, vast areas of permafrost are being degraded by climate change, which has the potential to release substantial quantities of nutrients, including nitrogen into large Arctic rivers. These rivers heavily influence the biogeochemistry of the Arctic Ocean, so it is important to understand the potential changes to rivers from permafrost degradation. This study utilized dissolved nitrogen species (nitrate and dissolved organic nitrogen (DON)) along with nitrogen isotope values (δ15N-NO and δ15N-DON) of samples collected from permafrost sites in the Kolyma River and the six largest Arctic rivers. Large inputs of DON and nitrate with a unique isotopically heavy δ15N signature were documented in the Kolyma, suggesting the occurrence of denitrification and highly invigorated nitrogen cycling in the Yedoma permafrost thaw zones along the Kolyma. We show evidence for permafrost-derived DON being recycled to nitrate as it passes through the river, transferring the high 15N signature to nitrate. However, the potential to observe these thaw signals at the mouths of rivers depends on the spatial scale of thaw sites, permafrost degradation, and recycling mechanisms. In contrast with the Kolyma, with near 100 % continuous permafrost extent, the Ob River, draining large areas of discontinuous and sporadic permafrost, shows large seasonal changes in both nitrate and DON isotopic signatures. During winter months, water percolating through peat soils records isotopically heavy denitrification signals in contrast with the lighter summer values when surface flow dominates. This early year denitrification signal was present to a degree in the Kolyma, but the ability to relate seasonal nitrogen signals across Arctic Rivers to permafrost degradation could not be shown with this study. Other large rivers in the Arctic show different seasonal nitrogen trends. Based on nitrogen isotope values, the vast majority of nitrogen fluxes in the Arctic rivers is from fresh DON sourced from surface runoff through organic-rich topsoil ... Article in Journal/Newspaper Arctic Arctic Arctic Ocean Climate change kolyma river ob river permafrost University of the Highlands and Islands: Research Database of UHI Biogeosciences 20 2 365 382 |
institution |
Open Polar |
collection |
University of the Highlands and Islands: Research Database of UHI |
op_collection_id |
ftuhipublicatio |
language |
English |
description |
Across the Arctic, vast areas of permafrost are being degraded by climate change, which has the potential to release substantial quantities of nutrients, including nitrogen into large Arctic rivers. These rivers heavily influence the biogeochemistry of the Arctic Ocean, so it is important to understand the potential changes to rivers from permafrost degradation. This study utilized dissolved nitrogen species (nitrate and dissolved organic nitrogen (DON)) along with nitrogen isotope values (δ15N-NO and δ15N-DON) of samples collected from permafrost sites in the Kolyma River and the six largest Arctic rivers. Large inputs of DON and nitrate with a unique isotopically heavy δ15N signature were documented in the Kolyma, suggesting the occurrence of denitrification and highly invigorated nitrogen cycling in the Yedoma permafrost thaw zones along the Kolyma. We show evidence for permafrost-derived DON being recycled to nitrate as it passes through the river, transferring the high 15N signature to nitrate. However, the potential to observe these thaw signals at the mouths of rivers depends on the spatial scale of thaw sites, permafrost degradation, and recycling mechanisms. In contrast with the Kolyma, with near 100 % continuous permafrost extent, the Ob River, draining large areas of discontinuous and sporadic permafrost, shows large seasonal changes in both nitrate and DON isotopic signatures. During winter months, water percolating through peat soils records isotopically heavy denitrification signals in contrast with the lighter summer values when surface flow dominates. This early year denitrification signal was present to a degree in the Kolyma, but the ability to relate seasonal nitrogen signals across Arctic Rivers to permafrost degradation could not be shown with this study. Other large rivers in the Arctic show different seasonal nitrogen trends. Based on nitrogen isotope values, the vast majority of nitrogen fluxes in the Arctic rivers is from fresh DON sourced from surface runoff through organic-rich topsoil ... |
format |
Article in Journal/Newspaper |
author |
Francis, Adam Ganeshram, Raja S. Tuerena, Robyn E. Spencer, Robert G. M. Holmes, Robert M. Rogers, Jennifer A. Mahaffey, Claire |
spellingShingle |
Francis, Adam Ganeshram, Raja S. Tuerena, Robyn E. Spencer, Robert G. M. Holmes, Robert M. Rogers, Jennifer A. Mahaffey, Claire Permafrost degradation and nitrogen cycling in Arctic rivers::insights from stable nitrogen isotope studies |
author_facet |
Francis, Adam Ganeshram, Raja S. Tuerena, Robyn E. Spencer, Robert G. M. Holmes, Robert M. Rogers, Jennifer A. Mahaffey, Claire |
author_sort |
Francis, Adam |
title |
Permafrost degradation and nitrogen cycling in Arctic rivers::insights from stable nitrogen isotope studies |
title_short |
Permafrost degradation and nitrogen cycling in Arctic rivers::insights from stable nitrogen isotope studies |
title_full |
Permafrost degradation and nitrogen cycling in Arctic rivers::insights from stable nitrogen isotope studies |
title_fullStr |
Permafrost degradation and nitrogen cycling in Arctic rivers::insights from stable nitrogen isotope studies |
title_full_unstemmed |
Permafrost degradation and nitrogen cycling in Arctic rivers::insights from stable nitrogen isotope studies |
title_sort |
permafrost degradation and nitrogen cycling in arctic rivers::insights from stable nitrogen isotope studies |
publishDate |
2023 |
url |
https://pure.uhi.ac.uk/en/publications/1b3d40fd-efb8-41aa-b385-98ac9bf4ff52 https://doi.org/10.5194/bg-20-365-2023 https://pureadmin.uhi.ac.uk/ws/files/32982444/bg_20_365_2023.pdf https://bg.copernicus.org/articles/20/365/2023/ |
genre |
Arctic Arctic Arctic Ocean Climate change kolyma river ob river permafrost |
genre_facet |
Arctic Arctic Arctic Ocean Climate change kolyma river ob river permafrost |
op_source |
Francis , A , Ganeshram , R S , Tuerena , R E , Spencer , R G M , Holmes , R M , Rogers , J A & Mahaffey , C 2023 , ' Permafrost degradation and nitrogen cycling in Arctic rivers: insights from stable nitrogen isotope studies ' , Biogeosciences , vol. 20 , no. 2 , pp. 365-382 . https://doi.org/10.5194/bg-20-365-2023 |
op_relation |
https://pure.uhi.ac.uk/en/publications/1b3d40fd-efb8-41aa-b385-98ac9bf4ff52 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/bg-20-365-2023 |
container_title |
Biogeosciences |
container_volume |
20 |
container_issue |
2 |
container_start_page |
365 |
op_container_end_page |
382 |
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1799471323909455872 |