https://repository.kopri.re.kr/handle/201206/9694 2026-04-16T10:49:06Z 2026-04-16T10:49:06Z Kim, Kang Eun Joo, Hyoung Min Lee, Taek-Kyun Kim, Hyun-Jung Kim, Yu Jin Kim, Bo Kyung Ha, Sun-Yong Jung, Seung Won https://repository.kopri.re.kr/handle/201206/16006 2025-08-21T04:51:39Z 2023-01-01T00:00:00Z

Title: Covariance of Marine Nucleocytoplasmic Large DNA Viruses with Eukaryotic Plankton Communities in the Sub-Arctic Kongsfjorden Ecosystem: A Metagenomic Analysis of Marine Microbial Ecosystems Authors: Kim, Kang Eun; Joo, Hyoung Min; Lee, Taek-Kyun; Kim, Hyun-Jung; Kim, Yu Jin; Kim, Bo Kyung; Ha, Sun-Yong; Jung, Seung Won Abstract: Nucleocytoplasmic large DNA viruses (NCLDVs) infect various marine eukaryotes. However, little is known about NCLDV diversity and their relationships with eukaryotic hosts in marine environments, the elucidation of which will advance the current understanding of marine ecosystems. This study characterizes the interplay between NCLDVs and the eukaryotic plankton community (EPC) in the sub-Arctic area using metagenomics and metabarcoding to investigate NCLDVs and EPC, respectively, in the Kongsfjorden ecosystem of Svalbard (Norway) in April and June 2018. Gyrodinium helveticum (Dinophyceae) is the most prevalent eukaryotic taxon in the EPC in April, during which time Mimiviridae (31.8%), Poxviridae (25.1%), Phycodnaviridae (14.7%) and Pandoraviridae (13.1%) predominate. However, in June, the predominant taxon is Aureococcus anophagefferens (Pelagophyceae), and the NCLDVs, Poxviridae (32.9%), Mimiviridae (29.1%), and Phycodnaviridae (18.5%) appear in higher proportions with an increase in Pelagophyceae, Bacillariophyceae, and Chlorophyta groups. Thus, differences in NCLDVs may be caused by changes in EPC composition in response to environmental changes, such as increases in water temperature and light intensity. Taken together, these findings are particularly relevant considering the anticipated impact of NCLDV-induced EPC control mechanisms on polar regions and, therefore, improve the understanding of the Sub-Arctic Kongsfjorden ecosystem.

2023-01-01T00:00:00Z Gal, Jong-Ku Kim, Bo Kyung Joo, Hyoung Min Shim, Chorom Lee, BoYeon Kim, Il-Nam Jung, Jinyoung Shin, Kyung-Hoon Ha, Sun-Yong https://repository.kopri.re.kr/handle/201206/13302 2022-04-14T06:58:20Z 2022-04-01T00:00:00Z

Title: Spatial distribution and origin of organic matters in an Arctic fjord system based on lipid biomarkers (n-alkanes and sterols) Authors: Gal, Jong-Ku; Kim, Bo Kyung; Joo, Hyoung Min; Shim, Chorom; Lee, BoYeon; Kim, Il-Nam; Jung, Jinyoung; Shin, Kyung-Hoon; Ha, Sun-Yong Abstract: The concentration of n-alkanes (C17-C35) and sterols in marine particulate matter were investigated to trace the origin of organic carbon in Kongsfjorden in early spring (April). The spatial distributions of environmental factors (seawater temperature, salinity, density, turbidity, chlorophyll a (chl. a) and particulate organic carbon (POC) concentrations) and the cell density of phytoplankton differed between the inner and outer fjord regions. In addition, brassicasterol, diatom biomarker, showed a high concentration in the outer fjord and positive correlations with the chl. a and POC concentrations in the water column. In contrast, some sterols originating from terrestrial organic matter (OM), such as stigmasterol and campesterol, showed relatively higher concentrations in the inner fjord than in the outer fjord. Based on the distance-based redundancy analysis (db-RDA) result, the distributions of organic compounds are predominantly controlled by the water density and the POC and chl. a concentrations, and these distributions allowed us to divide the inner and outer fjord regions. However, the hierarchical clustering of principal components (HCPC) results obtained based on principal component analysis (PCA) using lipid biomarkers (C17-C35 alkanes and sterols) and environmental factors indicated that the clusters were distinguished by surface (0 m) and subsurface (>4 m) seawater samples rather than by any regional division. Notably, the concentration of relatively short-chain alkanes (average chain length (ACL): 24.6 +/- 3.7) without a carbon preference for odd numbers (carbon preference index (CPI): 0.97 +/- 0.11) in the sea surface layer was significantly higher than that of subsurface seawater (ACL: 31.1 +/- 0.5 and CPI: 1.06 +/- 0.03) in the early spring. This suggests the potential of these compounds as indicators for tidewater glacier-derived OM and freshwater input by snow melt into the fjord system. Hence, these results demonstrate that the distributions of lipid biomarkers in the water column possibly provide important information for a comprehensive understanding of the origin and transport of OM in an Arctic fjord.

2022-04-01T00:00:00Z Kim, Kwanwoo Ha, Sun-Yong Kim, Bo Kyung Mundy, C. J. Gough, Kathleen M. Pogorzelec, Nicole M. Lee, Sang Heon https://repository.kopri.re.kr/handle/201206/12050 2022-03-24T07:14:59Z 2020-09-01T00:00:00Z

Title: Carbon and nitrogen uptake rates and macromolecular compositions of bottom-ice algae and phytoplankton at Cambridge Bay in Dease Strait, Canada Authors: Kim, Kwanwoo; Ha, Sun-Yong; Kim, Bo Kyung; Mundy, C. J.; Gough, Kathleen M.; Pogorzelec, Nicole M.; Lee, Sang Heon Abstract: Our understanding of ice algal responses to the recent changes in Arctic sea ice is impeded by limited field observations. In the present study, environmental characteristics of the landfast sea-ice zone as well as primary production and macromolecular composition of ice algae and phytoplankton were studied in the Kitikmeot Sea near Cambridge Bay in spring 2017. Averaged total chlorophyll-a (Chl-a) concentration was within the lower range reported previously for the same region, while daily carbon uptake rates of bottom-ice algae were significantly lower in this study than previously reported for the Arctic. Based on various indicators, the region's low nutrient concentrations appear to limit carbon uptake rates and associated accumulation of bottom-ice algal biomass. Furthermore, the lipids-dominant biochemical composition of bottom-ice algae suggests strong nutrient limitation relative to the distinctly different carbohydrates-dominant composition of phytoplankton. Together, the results confirm strong nitrate limitation of the local marine system.

2020-09-01T00:00:00Z Choi, Hyuntae Ha, Sun-Yong Lee, Seunghan Kim, Jee-Hoon Shin, Kyung-Hoon https://repository.kopri.re.kr/handle/201206/12051 2022-03-24T07:15:32Z 2020-07-01T00:00:00Z

Title: Trophic Dynamics of Zooplankton Before and After Polar Night in the Kongsfjorden (Svalbard): Evidence of Trophic Position Estimated by δ15N Analysis of Amino Acids Authors: Choi, Hyuntae; Ha, Sun-Yong; Lee, Seunghan; Kim, Jee-Hoon; Shin, Kyung-Hoon Abstract: In polar ecology, zooplankton diets and survival rates vary according to the seasonality of solar radiation and oceanographic conditions. Each zooplankton species has evolved feeding strategies to survive in the diet-limited conditions of the “polar night.” Many zooplankton studies have reported seasonal adaptations in feeding activity during polar night based on their trophic niches. Nitrogen isotope analysis of amino acids has provided improved accuracy in estimates of trophic position (TP) in various marine species. In this study, field work was conducted in Kongsfjorden before (October 2017) and after polar night (April 2018). As representative zooplankton, an amphipod (Themisto abyssorum), euphausids (Meganycitiphanes norvegica and Thysanoessa sp.), a chaetognath (Parasagitta elegans), and copepods (Calanus spp. and Oithona similis) were collected. trophic position values of each taxon were estimated using the nitrogen isotope ratio of glutamic acid (δ15NGlu) and phenylalanine (δ15NPhe). Results showed that TP values of P. elegans were relatively constant, averaging 3.2 in both seasons, likely due to continuous feeding activity during polar night. Trophic position values were also constant for Calanus spp., ranging 2.5-3.0 in both seasons, due to their ability to utilize stored high-energy wax. In contrast, average TP values for O. similis, an omnivorous zooplankton, were 2.9 in October and 2.3 the following April. Trophic position values for O. similis before polar night can be attributed to the relatively high availability of algae during longer periods of daylight. We found that TP variation in zooplankton before and after polar night differed according to feeding activities in diet-restricted circumstances.

2020-07-01T00:00:00Z