Sedimentary organic carbon dynamics in a glaciated Arctic fjord: tracing contributions of terrestrial and marine sources in the context of Atlantification over recent centuries

<p>In this study, we investigated sedimentary organic carbon (OC) dynamics in Kongsfjorden, Svalbard, using three multicores collected during the HH22 and HH23 cruises aboard the RV <i>Helmer Hanssen</i> in 2022 and 2023. We assessed the relative contributions of petrogenic, soil-d...

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Main Authors: D. Kim, J.-H. Kim, Y. Ahn, M. Forwick, S.-I. Nam
Format: Article
Language:English
Published: Copernicus Publications 2025-08-01
Series:Biogeosciences
Online Access:https://bg.copernicus.org/articles/22/4087/2025/bg-22-4087-2025.pdf
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author D. Kim
J.-H. Kim
Y. Ahn
M. Forwick
S.-I. Nam
author_facet D. Kim
J.-H. Kim
Y. Ahn
M. Forwick
S.-I. Nam
author_sort D. Kim
collection DOAJ
description <p>In this study, we investigated sedimentary organic carbon (OC) dynamics in Kongsfjorden, Svalbard, using three multicores collected during the HH22 and HH23 cruises aboard the RV <i>Helmer Hanssen</i> in 2022 and 2023. We assessed the relative contributions of petrogenic, soil-derived, plant-derived, and marine OC by applying a four-source apportionment approach based on <span class="inline-formula">Δ<sup>14</sup></span>C<span class="inline-formula"><sub>org</sub></span>, <span class="inline-formula"><i>δ</i><sup>13</sup></span>C<span class="inline-formula"><sub>org</sub></span>, and lignin parameters, including the (Ad <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M5" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="93e47eb16cb371fe6916d3191efc4f1d"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-22-4087-2025-ie00001.svg" width="8pt" height="14pt" src="bg-22-4087-2025-ie00001.png"/></svg:svg></span></span> Al)<span class="inline-formula"><sub><i>v</i></sub></span> ratio and lignin phenol concentrations, with Monte Carlo (MC) analysis. Age–depth models based on <span class="inline-formula"><sup>210</sup></span>Pb and <span class="inline-formula"><sup>226</sup></span>Ra data were used to evaluate temporal variations in the accumulation rates (ARs) of sedimentary OC. Our results revealed a marked increase in marine OC ARs over the past decades, closely linked to enhanced Atlantic Water (AW) inflow. The increasing AW influence in Arctic fjords observed in our record points to the potential for continued Atlantification under Arctic warming, as retreating sea ice and glaciers lower barriers to AW intrusion, enabling deeper and more persistent inflow. By putting this recent AW trend into historical context, our study provides valuable insights into the biogeochemical consequences of ongoing and future climate change in Arctic fjord systems.</p>
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spelling doaj-art-044efb80265243f199e325c5c4e94b842025-08-25T05:57:14ZengCopernicus PublicationsBiogeosciences1726-41701726-41892025-08-01224087410510.5194/bg-22-4087-2025Sedimentary organic carbon dynamics in a glaciated Arctic fjord: tracing contributions of terrestrial and marine sources in the context of Atlantification over recent centuriesD. Kim0J.-H. Kim1Y. Ahn2M. Forwick3S.-I. Nam4Division of Glacier and Earth Sciences, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 21990, South KoreaDivision of Glacier and Earth Sciences, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 21990, South KoreaDivision of Glacier and Earth Sciences, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 21990, South KoreaDepartment of Geosciences, UiT The Arctic University of Norway, 9037 Tromsø, NorwayDivision of Glacier and Earth Sciences, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 21990, South Korea<p>In this study, we investigated sedimentary organic carbon (OC) dynamics in Kongsfjorden, Svalbard, using three multicores collected during the HH22 and HH23 cruises aboard the RV <i>Helmer Hanssen</i> in 2022 and 2023. We assessed the relative contributions of petrogenic, soil-derived, plant-derived, and marine OC by applying a four-source apportionment approach based on <span class="inline-formula">Δ<sup>14</sup></span>C<span class="inline-formula"><sub>org</sub></span>, <span class="inline-formula"><i>δ</i><sup>13</sup></span>C<span class="inline-formula"><sub>org</sub></span>, and lignin parameters, including the (Ad <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M5" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="93e47eb16cb371fe6916d3191efc4f1d"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-22-4087-2025-ie00001.svg" width="8pt" height="14pt" src="bg-22-4087-2025-ie00001.png"/></svg:svg></span></span> Al)<span class="inline-formula"><sub><i>v</i></sub></span> ratio and lignin phenol concentrations, with Monte Carlo (MC) analysis. Age–depth models based on <span class="inline-formula"><sup>210</sup></span>Pb and <span class="inline-formula"><sup>226</sup></span>Ra data were used to evaluate temporal variations in the accumulation rates (ARs) of sedimentary OC. Our results revealed a marked increase in marine OC ARs over the past decades, closely linked to enhanced Atlantic Water (AW) inflow. The increasing AW influence in Arctic fjords observed in our record points to the potential for continued Atlantification under Arctic warming, as retreating sea ice and glaciers lower barriers to AW intrusion, enabling deeper and more persistent inflow. By putting this recent AW trend into historical context, our study provides valuable insights into the biogeochemical consequences of ongoing and future climate change in Arctic fjord systems.</p>https://bg.copernicus.org/articles/22/4087/2025/bg-22-4087-2025.pdf
spellingShingle D. Kim
J.-H. Kim
Y. Ahn
M. Forwick
S.-I. Nam
Sedimentary organic carbon dynamics in a glaciated Arctic fjord: tracing contributions of terrestrial and marine sources in the context of Atlantification over recent centuries
Biogeosciences
title Sedimentary organic carbon dynamics in a glaciated Arctic fjord: tracing contributions of terrestrial and marine sources in the context of Atlantification over recent centuries
title_full Sedimentary organic carbon dynamics in a glaciated Arctic fjord: tracing contributions of terrestrial and marine sources in the context of Atlantification over recent centuries
title_fullStr Sedimentary organic carbon dynamics in a glaciated Arctic fjord: tracing contributions of terrestrial and marine sources in the context of Atlantification over recent centuries
title_full_unstemmed Sedimentary organic carbon dynamics in a glaciated Arctic fjord: tracing contributions of terrestrial and marine sources in the context of Atlantification over recent centuries
title_short Sedimentary organic carbon dynamics in a glaciated Arctic fjord: tracing contributions of terrestrial and marine sources in the context of Atlantification over recent centuries
title_sort sedimentary organic carbon dynamics in a glaciated arctic fjord tracing contributions of terrestrial and marine sources in the context of atlantification over recent centuries
url https://bg.copernicus.org/articles/22/4087/2025/bg-22-4087-2025.pdf
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