https://repository.kopri.re.kr/handle/201206/15871 2026-04-08T16:11:07Z https://repository.kopri.re.kr/handle/201206/16567 Title: Holocene climate driving spatially variable mercury input to an Arctic fjord environment Authors: Son, Eun Jin; Lee, Ju Hyeon; Jang, Kwangchul; Ahn, Youngkyu; Jochen Knies; Matthias Forwick; Kim, Jung-Hyun; Nam, Seung-il; Kwon, Sae Yun Abstract: Mercury (Hg) is a globally distributed pollutant, affecting the Arctic through ocean and atmospheric circulation, coastal erosion, and riverine export from continents. We employ Hg stable isotopes and geochemical proxies to evaluate how climatic variation over the Holocene has influenced Hg sources in Arctic fjord environments. Hg isotopes measured in four sediment cores from western Svalbard are compared to gather insights into spatiotemporal variability of Hg sources and depositional history. Compared to other pre-industrial marine sediments, which are primarily influenced by wet deposition (precipitation) and terrestrial runoff, Hg sourced from bedrock erosion and Hg bound to particulate organic matter (pHg) transported by Atlantic Ocean currents are the dominant Hg sources to the Svalbard fjords. The temporal profiles of these two Hg sources vary spatially, with Kongsfjorden showing greater bedrock-Hg around 12.6 ka BP, while Woodfjorden and Dicksonfjorden exhibit higher influences at 8 ka and 4 ka BP, respectively. Despite these temporal differences, colder periods are generally dominated by Hg sourced from bedrock, whereas warmer periods are characterized by the contribution of pHg. In modern times, global anthropogenic activities have widespread Hg influences, whereas regional activities such as coal mining have little Hg influence. Our study highlights the importance of regional environmental setting and the global rise in anthropogenic activities in determining the spatiotemporal variation in Hg sources in Arctic over the Holocene. The findings provide insights into complex interactions between climate change and the Hg cycle in an Arctic fjord ecosystem. 2025-11-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/16571 Title: Climate, Fjord Morphology, and Oceanographic controls on Glacier Retreat and Sedimentation in Bellsund, Southwestern Svalbard Authors: Joe, Young Jin; Jang, K.; Ahn, Youngkyu; Matthias Forwick; Jan Sverre Laberg; CHRISTOPH VOGT; XIAO XIAOTONG; Son, Yeong Ju; Kim, Jung-Hyun; Nam, Seung-il Abstract: We investigate subbottom acoustic data combined with sedimentology and stratigraphy from a 470 cm­long sediment core from Bellsund, southwestern Svalbard, to reconstruct glacier dynamics and environmental change since the last deglaciation. Our results indicate that a marine­based glacier occupied Bellsund around 15 ka BP, subsequently retreated, with a temporary stillstand near the inner basin around 14 ka BP. By the onset of the Younger Dryas (YD), the glacier fronts had reached the mouths of the tributary fjords. Notably, glacier retreat in Bellsund progressed more slowly than in the adjacent Isfjorden, most likely due to topographic constrictions at the mouths of its tributary fjords (e.g., Eholmen and Akseløya), which acted as pinning points. No evidence is found for glacier re­advance during the YD. Following the YD, rapid glacier retreat into the tributary fjords contributed to meltwater discharge and terrestrial input, which in turn was associated with glacier­distal, glacimarine sedimentation with reduced ice rafting until 10.7 ka BP. During the early to middle Holocene (9.5？3.3 ka BP), Bellsund experienced a condensed sedimentary environment, likely reflecting the combined influence of intensified bottom current activity driven by Atlantic Water inflow, relative sea­level fall due to glacio­isostatic uplift, and local bathymetric highs. Since 3.3 ka BP, glacial influence in Bellsund has been dominated by input from the adjacent southern tributary fjord (Recherchefjorden). Our findings highlight the interplay of climate forcing, fjord morphology, and oceanographic processes in shaping glacier behavior and environmental change in glaciated Arctic fjord systems. 2025-09-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/16129 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 Authors: Kim, Dahae; Kim, Jung-Hyun; Ahn, Youngkyu; Forwick Matthias; Nam, Seung-il Abstract: 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 Helmer Hanssen 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 Delta 14Corg, delta 13Corg, and lignin parameters, including the (Ad / Al)v ratio and lignin phenol concentrations, with Monte Carlo (MC) analysis. Age-depth models based on 210Pb and 226Ra 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. 2025-08-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/16003 Title: Arctic fjord ecosystem adaptation to cryosphere meltdown over the past 14,000 years Authors: Knies Jochen; Ahn, Youngkyu; Ebner Berenice; Smik Lukas; Jang Kwangchul; Nam, Seung-il; Belt Simon T.; Schubert Carsten J. Abstract: The Arctic cryosphere is the epicentre of acute global change impact, with abrupt warming and amplification driving rapid sea ice decline and irreversible glacial ice loss. A key challenge is understanding how the cryosphere meltdown will impact Arctic marine carbon cycles and ecosystems. Here, we use organic geochemical biomarkers to trace the contribution of different planktonic groups to organic carbon in Arctic fjord sediments (Kongsfjorden, Svalbard) during past warmer and colder (than present) climate states. We show that phytoplankton community structures changed abruptly with variable sea ice cover and glacial ice loss. Our results imply that future deglaciation of Svalbard fjords will likely increase primary productivity in a "blue" (summer ice-free) scenario; however, the potential for fjords to serve as hotspots of marine organic carbon burial will likely be constrained due to warmer, stratified waters and reduced meltwater-induced supply of critical nutrients. 2025-04-01T00:00:00Z