https://repository.kopri.re.kr/handle/201206/14801 2026-03-10T13:00:32Z https://repository.kopri.re.kr/handle/201206/14851 Title: Distributions and potential sources of polychlorinated biphenyls and polycyclic aromatic hydrocarbons in the glacimarine sediments of Arctic Svalbard Authors: Lee Juhee; Kim Youngnam; Cha Jihyun; Kim, Dahae; Jang, Kwangchul; Kim, Jung-Hyun; Nam, Seung-il; Hong Seongjin Abstract: Distribution and sources of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in the glacimarine sediments (35 sites) of Svalbard were investigated. PCBs (32 congeners), traditional PAHs (15 homologs), emerging PAHs (11 homologs), and alkylated PAHs (16 homologs) were widely distributed in the Svalbard sediments (ranges: below method detection limit to 20, 21 to 3600, 1.0 to 1400, and 31 to 15,000 ng g-1 dry weight, respectively). Compositional analysis indicated that PCBs mainly originated from combustion sources, with PAHs being strongly influenced by local sources. Positive matrix factorization analysis showed that PAHs were associated with vehicle and petroleum combustion, coal, and coal combustion. Coal-derived PAHs contributed significantly to the sediments of Van Mijenfjorden. Remnants of coal mining activity trapped in the permafrost appear to enter the coastal environments as ground ice melts. Consequently, PAHs are currently emerging as the most significant contributors to potential risks in the Svalbard ecosystems. 2023-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/14884 Title: Application of Sedimentary Neodymium Isotopes to the Reconstruction of the Arctic Paleoceanography Authors: Jang, Kwangchul; Nam, Seung-il Abstract: Climate and environmental changes in the Arctic Ocean due to global warming have been linked to extreme climate change in mid-latitude regions, including the Korean Peninsula, requiring a better understanding of the Arctic climate system based on the paleo-analog. This review introduces three paleoenvironmental research cases using neodymium isotopes (143Nd/144Nd, εNd) measured on two different fractions of marine sediments: silicate-bound ‘detrital’ and Fe-Mn oxide-dominated ‘authigenic’ fractions. In the first case, detrital εNd in core HH17-1085-GC on the continental shelf off northern Svalbard was used for tracing changes in sediment provenance and associated glacier behavior over the last 16.3 ka. The second case showed the potential use of authigenic εNd as a quasi-conservative water mass tracer. Three prominent εNd peaks and troughs observed in core PS72/410-1 from the Mendeleev Ridge in the western Arctic Ocean over the past 76 ka suggested episodic meltwater discharge events during 51~46, 39~35 and 21~13 ka BP. The last case proposed the use of the difference between authigenic and detrital εNd as a proxy for reconstructing glacier fluctuation. The idea is based on the assumption that enhanced glacial erosion during glacier advances can supply sufficient freshly-exposed rock substrate for incongruent weathering, potentially leading to greater isotopic decoupling between bedrock and dissolved weathering products as recorded in detrital and authigenic εNd, respectively. Thus, it would be worthwhile to take advantage of sedimentary εNd to improve our understanding of past environmental changes in polar regions. 2023-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/14849 Title: Arctic deep-water anoxia and its potential role for ocean carbon sink during glacial periods Authors: Jang, Kwangchul; 우경식; Kim Jin-Kyoung; Nam, Seung-il Abstract: Deep water freshening beneath pan-Arctic ice shelves has recently been proposed based on the absence of excess thorium in glacial Arctic sediments. This profound proposal requires scrutiny of Arctic paleohydrology during past glacial periods. Here, we present structural and geochemical results of inorganic authigenic carbonates in deep-sea glacimarine sediments from the Mendeleev Ridge, western Arctic Ocean over the last 76 kyr. Our results suggest that Polar Deep Water in the western Arctic became brackish and anoxic during stadial periods. We argue that sediment-laden hyperpycnal meltwater discharged from paleo-ice sheets filled much of the water column depending upon the density, substantially reducing the salinity and oxygen content of the Polar Deep Water. Our findings suggest that this phenomenon was more extreme in the western Arctic Ocean and may point to the potential role of the western Arctic Ocean as an additional carbon reservoir in the global carbon cycle across glacial-interglacial cycles. Freshening and oxygen depletion of the polar deep waters of the Amerasian Basin during the last glacial periods probably resulted in significant carbon burial, according to geochemical analyses of inorganic authigenic carbonates in Arctic Ocean sediments. 2023-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/14875 Title: Commentary: Reply to commentary by Noormets and Kirchner on “Glacial history and depositional environments in little Storfjorden and Hambergbukta of Arctic Svalbard since the younger dryas” [Frontiers in Earth Science, (2022), 2211] Authors: Joe, Young Jin; Jang, Kwangchul; Matthias Forwick; Jan Sverre Laberg; Nam, Seung-il Abstract: The commentary by Noormets and Kirchner argues that the entire Terminal Moraine Complex (TMC) at the mouth of Hambergbukta would have formed by multiple glacier advances after the Younger Dryas. They pointed out that Joe et al. (2022) has overlooked the complex morphological features, especially the stacked debris flow lobes and flattened crest areas, of TMC to interpreted its formation. In this reply, we present an additional subbottom profiling data covering two sets (DFL-3 and DFL-2) of debris flow lobes defined by Noormets and Kirchner and further discuss for the the stacked debris lobes, the age model of the studied core, and iceberg-flattened crests of the TMC. Although a further investigation is necessary to better understand the behavior of the former tidewater glacier (Hambergbreen) in Hambergbukta, our conclusion is that the complex morphology of TMC could have formed during the latest Holocene including the Little Ice Age. 2023-01-01T00:00:00Z