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https://repository.kopri.re.kr/handle/201206/1
2024-01-14T10:50:10ZContrasting optical properties of dissolved organic matter between oceanic regions near the Getz and Dotson ice shelves in the Amundsen Sea, West Antarctica
https://repository.kopri.re.kr/handle/201206/15061
Title: Contrasting optical properties of dissolved organic matter between oceanic regions near the Getz and Dotson ice shelves in the Amundsen Sea, West Antarctica
Authors: 손주영; Jung, Jinyoung; Lee, Youngju; Kim, Tae-Wan; Park, Jisoo; 전미해; 박미옥
Abstract: The Amundsen Sea, located in West Antarctica, is experiencing rapid melting due to the intrusion of Circumpolar Deep Water, which is causing ice sheet thinning and basal melting. The resulting changes can affect the biogeochemical cycle of dissolved organic matter (DOM) by supplying iron from sea ice and/or glacier, thereby influencing primary production and ocean circulation. Therefore, it is crucial to understand the dynamics of the DOM in this region. In this study, our primary focus was to examine the optical properties of DOM in the oceanic regions adjacent to the West Getz Ice Shelf (WGIS) and the Dotson Ice Shelf (DIS). Significant differences in DOM optical properties, including the chromophoric DOM (CDOM) absorption coefficient at 350 nm (a350), spectral slope coefficient (S275-295), and specific UV absorbance at 254 nm (SUVA254), were observed between the WGIS and DIS regions (t-test, p < 0.05). Notably, the WGIS regions exhibited high a350 values. Additionally, the S275-295 and SUVA254 values, which serve as indices of molecular weight, indicated that the DOM pool in the WGIS regions was dominated by high molecular weight compounds with a substantial proportion of aromatic compounds. In contrast, the low values of a350 and SUVA254 along with the high S275-295 values in the DIS region suggested the dominance of low molecular weight CDOM associated with compounds of lower aromaticity. Furthermore, significant negative correlations were found between biomass of Phaeocystis antarctica (P. antarctica) and phosphate (PO4) in the WGIS regions (r2 = 0.82, p < 0.01 for WGIS 1 and r2 = 0.73, p < 0.01 for WGIS 2). However, no significant relationship was observed in the DIS region. These findings suggest that the high value and molecular weight of a350, extending from the surface layer to the deep layer, in the WGIS regions were associated with autochthonous sources, primarily driven by the colony-forming bloom of P. antarctica. These findings demonstrate that the quantity and quality of DOM in the Amundsen Sea are strongly affected by bloom conditions. The results emphasize that a combination of physical and biological processes interacts in complex ways to determine the characteristics of DOM in the Amundsen Sea.2024-01-01T00:00:00ZResponses of soil micro-eukaryotic communities to decadal drainage in a Siberian wet tussock tundra
https://repository.kopri.re.kr/handle/201206/15068
Title: Responses of soil micro-eukaryotic communities to decadal drainage in a Siberian wet tussock tundra
Authors: Myeong, Nu Ri; 권민정; Mathias Gockede; Binu M. Tripathi; Kim, Mincheol
Abstract: Climate warming holds the potential to cause extensive drying of wetlands in the Arctic, but the warming-drying effects on belowground ecosystems, particularly micro-eukaryotes, remain poorly understood. We investigated the responses of soil micro-eukaryotic communities, including fungi, protists, and microbial metazoa, to decadal drainage manipulation in a Siberian wet tundra using both amplicon and shotgun metagenomic sequencing. Our results indicate that drainage treatment increased the abundance of both fungal and non-fungal micro-eukaryotic communities, with key groups such as Ascomycota (mostly order Helotiales), Nematoda, and Tardigrada being notably abundant in drained sites. Functional traits analysis showed an increase in litter saprotrophic fungi and protistan consumers, indicating their increased activities in drained sites. The effects of drainage were more pronounced in the surface soil layer than the deeper layer, as soils dry and warm from the surface. Marked compositional shifts were observed for both communities, with fungal communities being more strongly influenced by drainage-induced vegetation change than the lowered water table itself, while the vegetation effect on non-fungal micro-eukaryotes was moderate. These findings provide insights into how belowground micro-eukaryotic communities respond to the widespread drying of wetlands in the Arctic and improve our predictive understanding of future ecosystem changes.2024-01-01T00:00:00ZEvidential deep learning for trustworthy prediction of enzyme commission number
https://repository.kopri.re.kr/handle/201206/15062
Title: Evidential deep learning for trustworthy prediction of enzyme commission number
Authors: Mingyu Park; So-Ra Han; Sai Kosaraju; JeungMin Lee; Hyun Lee; Lee, Jun Hyuck; Tae-Jin Oh; Mingon Kang
Abstract: The rapid growth of uncharacterized enzymes and their functional diversity urge accurate and trustworthy computational functional annotation tools. However, current state-of-the-art models lack trustworthiness on the prediction of the multilabel classification problem with thousands of classes. Here, we demonstrate that a novel evidential deep learning model (named ECPICK) makes trustworthy predictions of enzyme commission (EC) numbers with data-driven domain-relevant evidence, which results in significantly enhanced predictive power and the capability to discover potential new motif sites. ECPICK learns complex sequential patterns of amino acids and their hierarchical structures from 20 million enzyme data. ECPICK identifies significant amino acids that contribute to the prediction without multiple sequence alignment. Our intensive assessment showed not only outstanding enhancement of predictive performance on the largest databases of Uniprot, Protein Data Bank (PDB) and Kyoto Encyclopedia of Genes and Genomes (KEGG), but also a capability to discover new motif sites in microorganisms. ECPICK is a reliable EC number prediction tool to identify protein functions of an increasing number of uncharacterized enzymes.2024-01-01T00:00:00ZMapping Renewable Energy among Antarctic Research Stations
https://repository.kopri.re.kr/handle/201206/15069
Title: Mapping Renewable Energy among Antarctic Research Stations
Authors: Magnus de Witt; Chung, Changhyun; Lee, Joohan
Abstract: This paper presents an overview of current electricity generation and consumption patterns in the Antarctic. Based on both previously published and newly collected data, the paper describes the current status of renewable-energy use at research stations in the Antarctic. A more detailed view of electricity systems is also presented, demonstrating how different types of resources may be used and combined. The paper will serve as a guide to various renewable-energy generation technologies, highlighting well-established praxis, lessons learned, and potential ideas for im-provement. Several renewable electricity generation technologies that have proven effective for use in the Antarctic environment are described. as well as those that are currently in use. Finally, the paper summarizes the major lessons learned to support future projects and close the knowledge gap. The use of renewable-energy sources has the potential to reduce research stations’ greenhouse gas emissions, making research in Antarctica more sustainable. The availability of high-quality energy is crucial for survival and to allow scientists to conduct meaningful research at research stations under harsh Antarctic conditions.2024-01-01T00:00:00Z