https://repository.kopri.re.kr/handle/201206/15842 Wed, 08 Apr 2026 22:16:42 GMT 2026-04-08T22:16:42Z https://repository.kopri.re.kr/handle/201206/16474 Title: Environmental gradients shape microbial community structure and ecosystem processes in Antarctic lakes on King George Island Authors: Yoon, Jiyoung; Lee, Hanbyul; Han, Yeongcheol; Ha, Sun-Yong; Lee, Min Kyung; Park, Kitae; Jung, HyeJin; Kang, Cheon Yun; Chae, Yong-Un; Cho, Jang-Cheon; Kim, Ok-Sun Abstract: Antarctic lakes are extreme, oligotrophic habitats that contain microbial communities distinct from those of temperate freshwater systems. Our central question was whether these lakes host microbial communities distinct from those of non-Antarctic freshwater systems, and how environmental variability drives community differences among Antarctic lakes themselves. We analyzed the microbial community across five lakes on King George Island via high-throughput sequencing of amplicon sequence variants (ASVs) and biogeochemical profiling. The microbial communities were dominated by Bacteroidota, Actinomycetota, and Pseudomonadota, but varied strongly with environmental gradients such as salinity, sulfate, methane, and organic carbon. Hybrid ASVs, which were ubiquitous in both water and sediment, comprised the majority of sequences and indicate that dispersal processes, alongside environmental filtering, jointly structure lake microbial communities. Functional predictions further revealed lake- and habitat-specific pathways for carbon, nitrogen, and sulfur cycling, linking microbial diversity to ecosystem processes. These findings highlight how Antarctic lake microbes are shaped by both local selective pressures and cross-habitat exchange, providing critical insights into the resilience and vulnerability of polar freshwater ecosystems under climate change. Wed, 01 Oct 2025 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/16474 2025-10-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/16020 Title: Humic substance turnover by bacterial decomposers in the maritime Antarctic soil Authors: Kim, Dockyu; Kim, Mincheol; Woo, Sungho; Kim, Eungbin; Lee, Hyoungseok Abstract: Context Soil fungi and bacteria play a crucial role in decomposing soil organic matter (SOM) and providing nutrients to terrestrial ecosystems. However, in polar environments, their relative contributions to decomposition remain unclear.Aims This study aimed to determine whether fungi or bacteria contributes more to humic substances (HS) decomposition (the largest constituent of SOM) in maritime Antarctic soils under controlled laboratory conditions with elevated temperature and moisture levels.Methods Soil culturing method was used to select for soil microbes that efficiently degrade HS. During culturing at 18 degrees C for 30 days, Antarctic soils were treated with selective antimicrobials to manipulate microbial communities. After culturing, HS degradation and bacterial communities were analysed. The effects of soil culturing on plant growth were also evaluated using Arabidopsis thaliana as a surrogate for Antarctic plants.Key results HS decomposition and solubilisation were more pronounced in antifungal-treated soils compared to antibacterial-treated soils. Antifungal treatment reduced bacterial alpha diversity, altered bacterial composition, and increased the abundance of rhizosphere-associated Saccharibacteria. Bacterial growth resumed quickly after antibacterial treatment indicating resilience to antimicrobials. Soil culturing resulted in a higher water-soluble HS fraction, which significantly enhanced the fresh and dry weights of A. thaliana.Conclusions Antarctic bacteria exhibit higher degradative activity and resilience to antimicrobials compared to fungi, promoting HS decomposition and solubilisation. This indicates that bacteria have a greater impact on Antarctic soil functioning than fungi.Implications These findings highlight the critical role of bacteria in nutrient cycling and plant growth in polar ecosystems. Tue, 01 Jul 2025 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/16020 2025-07-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/16083 Title: Impacts of deglaciation on biodiversity and ecosystem function Authors: Gianalberto Losapio; Jasmine R. Lee; Ceridwen I. Fraser; Mark A. K. Gillespie; Nicky R. Kerr; Krzysztof Zawierucha; Trinity L. Hamilton; Scott Hotaling; Rudiger Kaufmann; Kim, Ok-Sun; Christian Klopsch; Yongqin Liu; Dzmitry Lukashanets; Sharon A. Robinson; Lee E. Brown Abstract: Glaciers and glacially influenced ecosystems host unique biodiversity spanning all kingdoms of life, but glaciers are retreating as the global climate warms, threatening specialist species, ecosystem functions and stability. We outline the impacts and consequences of glacier retreat, identifying key drivers and mechanisms of change, focusing on biodiversity and interactions among glacier, terrestrial, freshwater and marine ecosystems. We identify global glacial biodiversity patterns and local nuances, highlighting taxa that are likely to thrive or decline with the loss of glaciers. Following glacier retreat, the availability and size of ice-free areas initially increase, leading to a ‘biodiversity peak’. However, as glaciers disappear, the formation of novel habitats decreases while communities become more homogeneous and competition increases, leading to local-to-regional biodiversity decline. Glacier loss influences multiple ecosystem functions that contribute to climate regulation, freshwater resources, carbon and nutrient cycling, soil development, primary productivity and food-web stability. Key challenges in glacier ecosystem science include improving our knowledge of the relationships between biodiversity and ecosystem functions and quantifying species interactions at local-to-global scales to improve mechanistic understanding. Such advances will enhance predictions of how biodiversity will change with the loss of glaciers, enabling informed and effective conservation and management. Thu, 01 May 2025 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/16083 2025-05-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/16128 Title: Transcriptomic responses of Antarctic plants to in situ warming: uncovering molecular mechanisms behind physiological adjustments Authors: Min, Kyungwon; Syahril Sulaiman; Lee, Jungeun; Bravo Leon A.; Saez Patricia L.; Lee, Hyoungseok Abstract: ？ Background and Aims Previous studies using open-topped chambers to simulate warming in Antarctic field conditions have shown distinct physiological responses between the two Antarctic vascular plants Colobanthus quitensis and Deschampsia antarctica. Colobanthus quitensis exhibited significantly increased photosynthetic capacity and growth during in situ warming conditions, whereas D. antarctica showed no differences in these parameters. To understand the differences in ecological strategies of these plants in response to climate change, it is important to elucidate the molecular mechanisms underlying physiological responses. ？ Methods Transcriptome profiling was performed on plants from open-topped chambers and a control open area on King George Island, after three growing seasons. Differential gene expression was analysed using RNA sequencing, followed by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses to identify key biological processes affected by in situ warming. ？ Key Results Colobanthus quitensis exhibited significant upregulation of photosynthesis-related genes, including aquaporins, carbonic anhydrases and Rubisco activase, enhancing CO2 diffusion and assimilation. Conversely, D. antarctica showed downregulation of photosynthetic pathways but upregulation of genes related to flowering, including flowering-promoting factor and phytochrome-regulatory proteins. Both species showed molecular signatures suggesting reduced freezing tolerance in warming conditions, potentially increasing their susceptibility to frost damage. ？ Conclusions The results indicate distinct ecological strategies between the two plants in response to in situ warming. Colobanthus quitensis enhances its photosynthetic efficiency, whereas D. antarctica appears to accelerate its reproductive phase rather than focusing on growth. These findings contribute to our understanding of how Antarctic plants might respond to ongoing climate changes, with potential implications for their future resilience to extreme environmental conditions. Thu, 01 May 2025 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/16128 2025-05-01T00:00:00Z