Contrasts in dissolved, particulate, and sedimentary organic carbon from the Kolyma River to the East Siberian Shelf
<p>Arctic rivers will be increasingly affected by the hydrological and biogeochemical consequences of thawing permafrost. During transport, permafrost-derived organic carbon (OC) can either accumulate in floodplain and shelf sediments or be degraded into greenhouse gases prior to final burial....
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-01-01
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| Series: | Biogeosciences |
| Online Access: | https://bg.copernicus.org/articles/20/271/2023/bg-20-271-2023.pdf |
| _version_ | 1797951051108712448 |
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| author | D. Jong L. Bröder L. Bröder T. Tesi K. H. Keskitalo N. Zimov A. Davydova P. Pika N. Haghipour T. I. Eglinton J. E. Vonk |
| author_facet | D. Jong L. Bröder L. Bröder T. Tesi K. H. Keskitalo N. Zimov A. Davydova P. Pika N. Haghipour T. I. Eglinton J. E. Vonk |
| author_sort | D. Jong |
| collection | DOAJ |
| description | <p>Arctic rivers will be increasingly affected by the
hydrological and biogeochemical consequences of thawing permafrost. During
transport, permafrost-derived organic carbon (OC) can either accumulate in
floodplain and shelf sediments or be degraded into greenhouse gases prior to
final burial. Thus, the net impact of permafrost OC on climate will
ultimately depend on the interplay of complex processes that occur along the
source-to-sink system. Here, we focus on the Kolyma River, the largest
watershed completely underlain by continuous permafrost, and marine
sediments of the East Siberian Sea, as a transect to investigate the fate of
permafrost OC along the land–ocean continuum. Three pools of riverine OC
were investigated for the Kolyma main stem and five of its tributaries:
dissolved OC (DOC), suspended particulate OC (POC), and riverbed sediment OC
(SOC). They were compared with earlier findings in marine sediments. Carbon isotopes
(<span class="inline-formula"><i>δ</i><sup>13</sup>C</span>, <span class="inline-formula">Δ<sup>14</sup>C</span>), lignin phenol, and lipid biomarker
proxies show a contrasting composition and degradation state of these
different carbon pools. Dual C isotope source apportionment calculations
imply that old permafrost-OC is mostly associated with sediments (SOC;
contribution of <span class="inline-formula">68±10</span> %), and less dominant in POC (<span class="inline-formula">38±8</span> %), whereas autochthonous primary production contributes around <span class="inline-formula">44±10</span> % to POC in the main stem and up to <span class="inline-formula">79±11</span> % in tributaries.
Biomarker degradation indices suggest that Kolyma DOC might be relatively
degraded, regardless of its generally young age shown by previous studies.
In contrast, SOC shows the lowest <span class="inline-formula">Δ<sup>14</sup>C</span> value (oldest OC), yet
relatively fresh compositional signatures. Furthermore, decreasing mineral
surface area-normalised OC- and biomarker loadings suggest that SOC might be
reactive along the land–ocean continuum and almost all parameters were
subjected to rapid change when moving from freshwater to the marine
environment. This suggests that sedimentary dynamics play a crucial role
when targeting permafrost-derived OC in aquatic systems and support earlier
studies highlighting the fact that the land–ocean transition zone is an efficient
reactor and a dynamic environment. The prevailing inconsistencies between
freshwater and marine research (i.e. targeting predominantly DOC and SOC
respectively) need to be better aligned in order to determine to what degree
thawed permafrost OC may be destined for long-term burial, thereby
attenuating further global warming.</p> |
| first_indexed | 2024-04-10T22:24:39Z |
| format | Article |
| id | doaj.art-df7eeb7242fe41eeaaa4279a670e4156 |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-04-10T22:24:39Z |
| publishDate | 2023-01-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-df7eeb7242fe41eeaaa4279a670e41562023-01-17T09:50:35ZengCopernicus PublicationsBiogeosciences1726-41701726-41892023-01-012027129410.5194/bg-20-271-2023Contrasts in dissolved, particulate, and sedimentary organic carbon from the Kolyma River to the East Siberian ShelfD. Jong0L. Bröder1L. Bröder2T. Tesi3K. H. Keskitalo4N. Zimov5A. Davydova6P. Pika7N. Haghipour8T. I. Eglinton9J. E. Vonk10Department of Earth Sciences, Vrije Universiteit, Amsterdam, the NetherlandsDepartment of Earth Sciences, Vrije Universiteit, Amsterdam, the NetherlandsGeological Institute, Swiss Federal Institute of Technology, Zürich, SwitzerlandInstitute of Polar Sciences, National Research Council, Bologna, ItalyDepartment of Earth Sciences, Vrije Universiteit, Amsterdam, the NetherlandsPacific Geographical Institute, Far East Branch, Russian Academy of Sciences, Northeast Science Station, Cherskiy, RussiaPacific Geographical Institute, Far East Branch, Russian Academy of Sciences, Northeast Science Station, Cherskiy, RussiaDepartment of Earth Sciences, Vrije Universiteit, Amsterdam, the NetherlandsGeological Institute, Swiss Federal Institute of Technology, Zürich, SwitzerlandGeological Institute, Swiss Federal Institute of Technology, Zürich, SwitzerlandDepartment of Earth Sciences, Vrije Universiteit, Amsterdam, the Netherlands<p>Arctic rivers will be increasingly affected by the hydrological and biogeochemical consequences of thawing permafrost. During transport, permafrost-derived organic carbon (OC) can either accumulate in floodplain and shelf sediments or be degraded into greenhouse gases prior to final burial. Thus, the net impact of permafrost OC on climate will ultimately depend on the interplay of complex processes that occur along the source-to-sink system. Here, we focus on the Kolyma River, the largest watershed completely underlain by continuous permafrost, and marine sediments of the East Siberian Sea, as a transect to investigate the fate of permafrost OC along the land–ocean continuum. Three pools of riverine OC were investigated for the Kolyma main stem and five of its tributaries: dissolved OC (DOC), suspended particulate OC (POC), and riverbed sediment OC (SOC). They were compared with earlier findings in marine sediments. Carbon isotopes (<span class="inline-formula"><i>δ</i><sup>13</sup>C</span>, <span class="inline-formula">Δ<sup>14</sup>C</span>), lignin phenol, and lipid biomarker proxies show a contrasting composition and degradation state of these different carbon pools. Dual C isotope source apportionment calculations imply that old permafrost-OC is mostly associated with sediments (SOC; contribution of <span class="inline-formula">68±10</span> %), and less dominant in POC (<span class="inline-formula">38±8</span> %), whereas autochthonous primary production contributes around <span class="inline-formula">44±10</span> % to POC in the main stem and up to <span class="inline-formula">79±11</span> % in tributaries. Biomarker degradation indices suggest that Kolyma DOC might be relatively degraded, regardless of its generally young age shown by previous studies. In contrast, SOC shows the lowest <span class="inline-formula">Δ<sup>14</sup>C</span> value (oldest OC), yet relatively fresh compositional signatures. Furthermore, decreasing mineral surface area-normalised OC- and biomarker loadings suggest that SOC might be reactive along the land–ocean continuum and almost all parameters were subjected to rapid change when moving from freshwater to the marine environment. This suggests that sedimentary dynamics play a crucial role when targeting permafrost-derived OC in aquatic systems and support earlier studies highlighting the fact that the land–ocean transition zone is an efficient reactor and a dynamic environment. The prevailing inconsistencies between freshwater and marine research (i.e. targeting predominantly DOC and SOC respectively) need to be better aligned in order to determine to what degree thawed permafrost OC may be destined for long-term burial, thereby attenuating further global warming.</p>https://bg.copernicus.org/articles/20/271/2023/bg-20-271-2023.pdf |
| spellingShingle | D. Jong L. Bröder L. Bröder T. Tesi K. H. Keskitalo N. Zimov A. Davydova P. Pika N. Haghipour T. I. Eglinton J. E. Vonk Contrasts in dissolved, particulate, and sedimentary organic carbon from the Kolyma River to the East Siberian Shelf Biogeosciences |
| title | Contrasts in dissolved, particulate, and sedimentary organic carbon from the Kolyma River to the East Siberian Shelf |
| title_full | Contrasts in dissolved, particulate, and sedimentary organic carbon from the Kolyma River to the East Siberian Shelf |
| title_fullStr | Contrasts in dissolved, particulate, and sedimentary organic carbon from the Kolyma River to the East Siberian Shelf |
| title_full_unstemmed | Contrasts in dissolved, particulate, and sedimentary organic carbon from the Kolyma River to the East Siberian Shelf |
| title_short | Contrasts in dissolved, particulate, and sedimentary organic carbon from the Kolyma River to the East Siberian Shelf |
| title_sort | contrasts in dissolved particulate and sedimentary organic carbon from the kolyma river to the east siberian shelf |
| url | https://bg.copernicus.org/articles/20/271/2023/bg-20-271-2023.pdf |
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