https://repository.kopri.re.kr/handle/201206/5492 Tue, 14 Apr 2026 19:08:52 GMT 2026-04-14T19:08:52Z https://repository.kopri.re.kr/handle/201206/12285 Title: A Novel Paleo Sea Surface Nutrient Proxy Based on Long Chain Alkyl Diols: Nutrient Diol Index (NDI) Authors: Gal, Jong-Ku; Kim, Jung-Hyun; Shin, Kyung-Hoon Abstract: During recent years, several diol-based indices have been introduced to provide information on past climatic and environmental conditions. Here, we investigated the distribution of long chain diols (LCDs) using suspended particulate matter (SPM) collected along a south-north transect ranging from the East Sea of Korea to the Bering Sea in the northwestern Pacific region. Our results shed light on the spatial distribution pattern of LCDs in the Pacific Ocean, showing that both saturated and unsaturated C28 and C30 1,14-diols were dominant in most SPM samples. The principal component analysis (PCA) results indicated that the C28:1 and C30:1 1,14-diols were positively associated with nutrient concentrations. However, only the C28:1 1,14-diol in addition to the C28 1,14-diol was positively associated with nutrient concentrations in the global surface sediment data set previously published, while the C30:1 1,14-diol was related to sea surface temperature (SST). Based on these observations, we developed the nutrient diol index (NDI) as follows: Nutrient diol index (NDI) =([C_28 1,14]+[C_(28:1) 1,14])/([C_28 1,14]+[C_(28:1) 1,14]+[C_30 1,14]+[C_(30:1) 1,14]+[C_28 1,13]+[C_30 1,13]+[C_30 1,15] ) The NDI was positively associated with the ocean atlas values of surface water phosphate and nitrate concentrations for the SPM and surface sediment data sets (Fig. 1). Accordingly, the results of our study showed that the NDI has potential as a quantitative nutrient proxy for estimating sea surface phosphate (or nitrate) changes. Definitely, more works are needed to assess the NDI applicability for reconstructing surface water nutrient variations in the past, by analysing more SPM and sediment cores collected from various oceanic settings. Tue, 01 Jan 2019 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/12285 2019-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/9126 Title: Paleo-sea ice proxy development and validation in the Chukchi Sea and the Ross Sea Authors: Kim, Junghyun Fri, 14 Jul 2017 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/9126 2017-07-14T00:00:00Z https://repository.kopri.re.kr/handle/201206/5863 Title: Distribution of pelagic phytoplankton-derived lipid biomarkers along a transect from the East Sea to the Bering Sea : insights into their suitability as open-water indicators Authors: Gal, Jong-Ku; Shin, Kyung-Hoon; Nam, Seung-il; Simon T. Belt; Ha, Sun-Yong; Lukas Smik; Kim, Junghyun Abstract: In this study we collected suspended particulate matter (SPM) along a transect from the East Sea to the Bering Sea from 18 to 28 July in 2015. We then analyzed the samples for the Arctic sea ice proxy IP25 together with various phytoplankton-derived lipids including a tri-unsaturated highly branched isoprenoid (HBI triene) and two sterols (brassicasterol and dinosterol) to assess the suitability of these compounds for the so-called PIP25 index in the western Arctic region as a proxy for sea ice change in the past. The distributions of some other commonly reported sterols (cholesterol and 24-methylene cholesterol) were also investigated. IP25 could not be detected in any of the samples analyzed, consistent with the nature of the sampling location and season, while the HBI triene was only detected at five sampling sites in the Northwest Pacific and the Bering Sea. In contrast, each of the sterols were detected at each sampling site. Interestingly, brassicasterol concentration showed a strong, positive relationship with cholesterol concentration, but no relationship with chlorophyll a, suggesting that the former might have been associated with not only marine phytoplankton but other sources in the study area, such as zooplankton. Sun, 01 Jan 2017 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/5863 2017-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/5928 Title: Effect of Different GC Columns on the Quantitative Analysisof Long Chain Alkyl Diols (LCDs) Authors: Gal, Jong-Ku; Shin, Kyung-Hoon; Nam, Seung-il; Kim, Junghyun Abstract: Long chain alkyl diols (LCDs)은 다양한 해양 환경 퇴적물에서 관측되고 있다. Rampen et al. (2012)은 해양 표층 퇴적물에서 분석된 LCDs 중 C30 1,15-diol, C28 1,13-diol, C30 1,13-diol를 이용하여 Long chain Diol Index (LDI)라는 고수온 프록시를 제시하였다. 일반 적으로 LCDs의 정성 및 정량 분석은 CP-Sil5CB와 DB-5ms 컬럼을 사용해 GC-MS를 주 기반으로 한다. 본 연구에서는 서로 다른 해 양환경(동해 및 서북극해)에서 획득한 해양퇴적물을 활용하여 특성이 다른 세가지 GC 컬럼(CP-Sil5CB, HP-5ms, DB-5)이 LCDs의 정량 분석에 미치는 영향을 검토하였다. 본 연구를 통해 일반적으로 CP-Sil5CB로 분석된 농도 결과가 HP-5ms와 DB-5로 분석된 농 도 결과와 통계적으로 유의한 차이가 있는 것으로 확인되었다. 하지만 LDI로 복원된 표층수온의 컬럼 간 편차는 동해 퇴적물의 경 우 0.1-0.2°C, 서북극해 퇴적물의 경우 0.2-0.7°C로 LDI의 calibration error 범위(± 1σ) 보다 작았다. 결론적으로 본 연구는 컬럼에 따 라 LCDs의 정량 결과는 현저한 차이를 보일 수 있지만, LDI 프록시 값에 미치는 영향은 상대적으로 미비함을 보여 주었다. 따라서 LDI 프록시를 활용한 동해 및 서북극 해양 퇴적물의 고수온 복원에 특성이 다른 컬럼을 사용 할 수 있음을 시사하였다. Sun, 01 Jan 2017 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/5928 2017-01-01T00:00:00Z