Cargando…

Canadian permafrost stores large pools of ammonium and optically distinct dissolved organic matter

Permafrost degradation may lead to mobilization of carbon and nutrients and enhance microbial processing rates of previously frozen organic matter. Although the pool size and chemical composition of dissolved organic matter (DOM) are fundamental determinants of the carbon cycle in Arctic watersheds,...

Descripción completa

Detalles Bibliográficos
Autores principales: Fouché, J., Christiansen, C. T., Lafrenière, M. J., Grogan, P., Lamoureux, S. F.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7481224/
https://www.ncbi.nlm.nih.gov/pubmed/32908152
http://dx.doi.org/10.1038/s41467-020-18331-w
_version_ 1783580553861136384
author Fouché, J.
Christiansen, C. T.
Lafrenière, M. J.
Grogan, P.
Lamoureux, S. F.
author_facet Fouché, J.
Christiansen, C. T.
Lafrenière, M. J.
Grogan, P.
Lamoureux, S. F.
author_sort Fouché, J.
collection PubMed
description Permafrost degradation may lead to mobilization of carbon and nutrients and enhance microbial processing rates of previously frozen organic matter. Although the pool size and chemical composition of dissolved organic matter (DOM) are fundamental determinants of the carbon cycle in Arctic watersheds, its source within the seasonally thawing active layer and the underlying permafrost remains largely uncharacterized. Here, we used 25 soil cores that extended down into the permafrost from nine sites across Arctic Canada to quantify dissolved organic carbon (DOC) and nitrogen stocks, and to characterize DOM optical properties. Organic permafrost stores 5–7 times more DOC and ammonium than the active layer and mineral permafrost. Furthermore, the permafrost layers contain substantial low molecular weight DOM with low aromaticity suggesting high biodegradability. We conclude that soil organic matter stoichiometry and cryogenic processes determine permafrost DOM chemistry, and that thawing will mobilize large amounts of labile DOC and ammonium into Arctic watersheds.
format Online
Article
Text
id pubmed-7481224
institution National Center for Biotechnology Information
language English
publishDate 2020
publisher Nature Publishing Group UK
record_format MEDLINE/PubMed
spelling pubmed-74812242020-09-21 Canadian permafrost stores large pools of ammonium and optically distinct dissolved organic matter Fouché, J. Christiansen, C. T. Lafrenière, M. J. Grogan, P. Lamoureux, S. F. Nat Commun Article Permafrost degradation may lead to mobilization of carbon and nutrients and enhance microbial processing rates of previously frozen organic matter. Although the pool size and chemical composition of dissolved organic matter (DOM) are fundamental determinants of the carbon cycle in Arctic watersheds, its source within the seasonally thawing active layer and the underlying permafrost remains largely uncharacterized. Here, we used 25 soil cores that extended down into the permafrost from nine sites across Arctic Canada to quantify dissolved organic carbon (DOC) and nitrogen stocks, and to characterize DOM optical properties. Organic permafrost stores 5–7 times more DOC and ammonium than the active layer and mineral permafrost. Furthermore, the permafrost layers contain substantial low molecular weight DOM with low aromaticity suggesting high biodegradability. We conclude that soil organic matter stoichiometry and cryogenic processes determine permafrost DOM chemistry, and that thawing will mobilize large amounts of labile DOC and ammonium into Arctic watersheds. Nature Publishing Group UK 2020-09-09 /pmc/articles/PMC7481224/ /pubmed/32908152 http://dx.doi.org/10.1038/s41467-020-18331-w Text en © The Author(s) 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Fouché, J.
Christiansen, C. T.
Lafrenière, M. J.
Grogan, P.
Lamoureux, S. F.
Canadian permafrost stores large pools of ammonium and optically distinct dissolved organic matter
title Canadian permafrost stores large pools of ammonium and optically distinct dissolved organic matter
title_full Canadian permafrost stores large pools of ammonium and optically distinct dissolved organic matter
title_fullStr Canadian permafrost stores large pools of ammonium and optically distinct dissolved organic matter
title_full_unstemmed Canadian permafrost stores large pools of ammonium and optically distinct dissolved organic matter
title_short Canadian permafrost stores large pools of ammonium and optically distinct dissolved organic matter
title_sort canadian permafrost stores large pools of ammonium and optically distinct dissolved organic matter
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7481224/
https://www.ncbi.nlm.nih.gov/pubmed/32908152
http://dx.doi.org/10.1038/s41467-020-18331-w
work_keys_str_mv AT fouchej canadianpermafroststoreslargepoolsofammoniumandopticallydistinctdissolvedorganicmatter
AT christiansenct canadianpermafroststoreslargepoolsofammoniumandopticallydistinctdissolvedorganicmatter
AT lafrenieremj canadianpermafroststoreslargepoolsofammoniumandopticallydistinctdissolvedorganicmatter
AT groganp canadianpermafroststoreslargepoolsofammoniumandopticallydistinctdissolvedorganicmatter
AT lamoureuxsf canadianpermafroststoreslargepoolsofammoniumandopticallydistinctdissolvedorganicmatter