Seasonal variability in particulate organic carbon degradation in the Kolyma River, Siberia
Abstract Major Arctic rivers are undergoing changes due to climate warming with higher discharge and increased amounts of solutes and organic carbon (OC) draining into rivers and coastal seas. Permafrost thaw mobilizes previously frozen OC to the fluvial network where it can be degraded into greenho...
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Online Access: | http://dx.doi.org/10.1088/1748-9326/ac4f8d https://iopscience.iop.org/article/10.1088/1748-9326/ac4f8d https://iopscience.iop.org/article/10.1088/1748-9326/ac4f8d/pdf |
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crioppubl:10.1088/1748-9326/ac4f8d 2024-09-15T18:17:00+00:00 Seasonal variability in particulate organic carbon degradation in the Kolyma River, Siberia Keskitalo, Kirsi H Bröder, Lisa Jong, Dirk Zimov, Nikita Davydova, Anna Davydov, Sergei Tesi, Tommaso Mann, Paul J Haghipour, Negar Eglinton, Timothy I Vonk, Jorien E H2020 European Research Council 2022 http://dx.doi.org/10.1088/1748-9326/ac4f8d https://iopscience.iop.org/article/10.1088/1748-9326/ac4f8d https://iopscience.iop.org/article/10.1088/1748-9326/ac4f8d/pdf unknown IOP Publishing http://creativecommons.org/licenses/by/4.0 https://iopscience.iop.org/info/page/text-and-data-mining Environmental Research Letters volume 17, issue 3, page 034007 ISSN 1748-9326 journal-article 2022 crioppubl https://doi.org/10.1088/1748-9326/ac4f8d 2024-09-02T04:13:53Z Abstract Major Arctic rivers are undergoing changes due to climate warming with higher discharge and increased amounts of solutes and organic carbon (OC) draining into rivers and coastal seas. Permafrost thaw mobilizes previously frozen OC to the fluvial network where it can be degraded into greenhouse gases and emitted to the atmosphere. Degradation of OC during downstream transport, especially of the particulate OC (POC), is however poorly characterized. Here, we quantified POC degradation in the Kolyma River, the largest river system underlain with continuous permafrost, during 9–15 d whole-water incubations (containing POC and dissolved OC—DOC) during two seasons: spring freshet (early June) and late summer (end of July). Furthermore, we examined interactions between dissolved and particulate phases using parallel incubations of filtered water (only DOC). We measured OC concentrations and carbon isotopes (δ 13 C, Δ 14 C) to define carbon losses and to characterize OC composition, respectively. We found that both POC composition and biodegradability differs greatly between seasons. During summer, POC was predominantly autochthonous (47%–95%) and degraded rapidly (∼33% loss) whereas freshet POC was largely of allochthonous origin (77%–96%) and less degradable. Gains in POC concentrations (up to 31%) were observed in freshet waters that could be attributed to flocculation and adsorption of DOC to particles. The demonstrated DOC flocculation and adsorption to POC indicates that the fate and dynamics of the substantially-sized DOC pool may shift from degradation to settling, depending on season and POC concentrations—the latter potentially acting to attenuate greenhouse gas emissions from fluvial systems. We finally note that DOC incubations without POC present may yield degradation estimates that do not reflect degradation in the in situ river conditions, and that interaction between dissolved and particulate phases may be important to consider when determining fluvial carbon dynamics and feedbacks under a ... Article in Journal/Newspaper kolyma river permafrost Siberia IOP Publishing Environmental Research Letters |
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Abstract Major Arctic rivers are undergoing changes due to climate warming with higher discharge and increased amounts of solutes and organic carbon (OC) draining into rivers and coastal seas. Permafrost thaw mobilizes previously frozen OC to the fluvial network where it can be degraded into greenhouse gases and emitted to the atmosphere. Degradation of OC during downstream transport, especially of the particulate OC (POC), is however poorly characterized. Here, we quantified POC degradation in the Kolyma River, the largest river system underlain with continuous permafrost, during 9–15 d whole-water incubations (containing POC and dissolved OC—DOC) during two seasons: spring freshet (early June) and late summer (end of July). Furthermore, we examined interactions between dissolved and particulate phases using parallel incubations of filtered water (only DOC). We measured OC concentrations and carbon isotopes (δ 13 C, Δ 14 C) to define carbon losses and to characterize OC composition, respectively. We found that both POC composition and biodegradability differs greatly between seasons. During summer, POC was predominantly autochthonous (47%–95%) and degraded rapidly (∼33% loss) whereas freshet POC was largely of allochthonous origin (77%–96%) and less degradable. Gains in POC concentrations (up to 31%) were observed in freshet waters that could be attributed to flocculation and adsorption of DOC to particles. The demonstrated DOC flocculation and adsorption to POC indicates that the fate and dynamics of the substantially-sized DOC pool may shift from degradation to settling, depending on season and POC concentrations—the latter potentially acting to attenuate greenhouse gas emissions from fluvial systems. We finally note that DOC incubations without POC present may yield degradation estimates that do not reflect degradation in the in situ river conditions, and that interaction between dissolved and particulate phases may be important to consider when determining fluvial carbon dynamics and feedbacks under a ... |
author2 |
H2020 European Research Council |
format |
Article in Journal/Newspaper |
author |
Keskitalo, Kirsi H Bröder, Lisa Jong, Dirk Zimov, Nikita Davydova, Anna Davydov, Sergei Tesi, Tommaso Mann, Paul J Haghipour, Negar Eglinton, Timothy I Vonk, Jorien E |
spellingShingle |
Keskitalo, Kirsi H Bröder, Lisa Jong, Dirk Zimov, Nikita Davydova, Anna Davydov, Sergei Tesi, Tommaso Mann, Paul J Haghipour, Negar Eglinton, Timothy I Vonk, Jorien E Seasonal variability in particulate organic carbon degradation in the Kolyma River, Siberia |
author_facet |
Keskitalo, Kirsi H Bröder, Lisa Jong, Dirk Zimov, Nikita Davydova, Anna Davydov, Sergei Tesi, Tommaso Mann, Paul J Haghipour, Negar Eglinton, Timothy I Vonk, Jorien E |
author_sort |
Keskitalo, Kirsi H |
title |
Seasonal variability in particulate organic carbon degradation in the Kolyma River, Siberia |
title_short |
Seasonal variability in particulate organic carbon degradation in the Kolyma River, Siberia |
title_full |
Seasonal variability in particulate organic carbon degradation in the Kolyma River, Siberia |
title_fullStr |
Seasonal variability in particulate organic carbon degradation in the Kolyma River, Siberia |
title_full_unstemmed |
Seasonal variability in particulate organic carbon degradation in the Kolyma River, Siberia |
title_sort |
seasonal variability in particulate organic carbon degradation in the kolyma river, siberia |
publisher |
IOP Publishing |
publishDate |
2022 |
url |
http://dx.doi.org/10.1088/1748-9326/ac4f8d https://iopscience.iop.org/article/10.1088/1748-9326/ac4f8d https://iopscience.iop.org/article/10.1088/1748-9326/ac4f8d/pdf |
genre |
kolyma river permafrost Siberia |
genre_facet |
kolyma river permafrost Siberia |
op_source |
Environmental Research Letters volume 17, issue 3, page 034007 ISSN 1748-9326 |
op_rights |
http://creativecommons.org/licenses/by/4.0 https://iopscience.iop.org/info/page/text-and-data-mining |
op_doi |
https://doi.org/10.1088/1748-9326/ac4f8d |
container_title |
Environmental Research Letters |
_version_ |
1810454991301771264 |