https://repository.kopri.re.kr/handle/201206/13409 Sat, 11 Apr 2026 14:11:37 GMT 2026-04-11T14:11:37Z https://repository.kopri.re.kr/handle/201206/15662 Title: Vulnerability of Brassica oleracea L. (cabbage) grown in microplastic-contaminated soil to extreme climatic events associated with freeze-thaw Authors: Min, Kyungwon; Kim, Gyuwon; Lee, Hyoungseok; Kim, Young-Kwan; Lee, Sung-Eun; Lee, Sang-Ryong Abstract: Climate change and environmental pollution have increased the frequency and severity of extreme weather events, exposing plants to multifactorial stress conditions that are poorly understood. While extensive research has explored plant responses to individual stress factors, the impact of combined stresses-such as microplastic (MP) contamination and freeze-thaw cycles-remains largely unexamined. This research investigated how soil microplastic pollution affects the freezing tolerance of cabbage (Brassica oleracea L.), a crop vulnerable to unexpected frosts. Seedlings were grown in soils containing varying MP concentrations (0 %, 2 %, 5 %, and 10 % w/w), and their physiological responses to freezing events (-2.5 degrees C and -3.5 degrees C) were assessed. Our findings revealed that although MP particles were not detected in leaf tissues, MP contamination significantly reduced freezing tolerance in a dose-dependent manner. Plants grown in 10 % MP-treated soil exhibited higher membrane damage, as indicated by increased ion leakage and malondialdehyde levels, and showed more severe oxidative stress, with elevated superoxide (O-2(center dot-)) and hydrogen peroxide (H2O2) accumulation. These stress responses corresponded with suppressed antioxidant enzyme activities, including catalase (CAT), ascorbate peroxidase (APX), and superoxide dismutase (SOD). Principal component analysis (PCA) demonstrated distinct physiological patterns between control and MP-treated plants, emphasizing the disruptive impact of MP pollution on stress resilience. This study provides the first empirical evidence that soil microplastic contamination compromises plant tolerance to freeze-thaw cycles, highlighting an overlooked risk to crop performance in changing environmental conditions and calling for further research into the long-term ecological consequences of terrestrial MP pollution. Tue, 01 Apr 2025 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/15662 2025-04-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/16223 Title: Microbial assemblages and associated biogeochemical processes in Lake Bonney, a permanently ice-covered lake in the McMurdo Dry Valleys, Antarctica Authors: Lee, Hanbyul; Hwang, Kyuin; Cho, Ahnna; Kim, Soyeon; Kim, Minkyung; Morgan-Kiss Rachael; Priscu John C.; Kim, Kyung Mo; Kim, Ok-Sun Abstract: BackgroundLake Bonney, which is divided into a west lobe (WLB) and an east lobe (ELB), is a perennially ice-covered lake located in the McMurdo Dry Valleys of Antarctica. Despite previous reports on the microbial community dynamics of ice-covered lakes in this region, there is a paucity of information on the relationship between microbial genomic diversity and associated nutrient cycling. Here, we applied gene- and genome-centric approaches to investigate the microbial ecology and reconstruct microbial metabolic potential along the depth gradient in Lake Bonney.ResultsLake Bonney is strongly chemically stratified with three distinct redox zones, yielding different microbial niches. Our genome enabled approach revealed that in the sunlit and relatively freshwater epilimnion, oxygenic photosynthetic production by the cyanobacterium Pseudanabaena and a diversity of protists and microalgae may provide new organic carbon to the environment. CO-oxidizing bacteria, such as Acidimicrobiales, Nanopelagicales, and Burkholderiaceae were also prominent in the epilimnion and their ability to oxidize carbon monoxide to carbon dioxide may serve as a supplementary energy conservation strategy. In the more saline metalimnion of ELB, an accumulation of inorganic nitrogen and phosphorus supports photosynthesis despite relatively low light levels. Conversely, in WLB the release of organic rich subglacial discharge from Taylor Glacier into WLB would be implicated in the possible high abundance of heterotrophs supported by increased potential for glycolysis, beta-oxidation, and glycoside hydrolase and may contribute to the growth of iron reducers in the dark and extremely saline hypolimnion of WLB. The suboxic and subzero temperature zones beneath the metalimnia in both lobes supported microorganisms capable of utilizing reduced nitrogens and sulfurs as electron donors. Heterotrophs, including nitrate reducing sulfur oxidizing bacteria, such as Acidimicrobiales (MAG72) and Salinisphaeraceae (MAG109), and denitrifying bacteria, such as Gracilimonas (MAG7), Acidimicrobiales (MAG72) and Salinisphaeraceae (MAG109), dominated the hypolimnion of WLB, whereas the environmental harshness of the hypolimnion of ELB was supported by the relatively low in metabolic potential, as well as the abundance of halophile Halomonas and endospore-forming Virgibacillus.ConclusionsThe vertical distribution of microbially driven C, N and S cycling genes/pathways in Lake Bonney reveals the importance of geochemical gradients to microbial diversity and biogeochemical cycles with the vertical water column. Mon, 01 Jan 2024 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/16223 2024-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/15165 Title: Ecophysiology of Antarctic Terrestrial Organisms to Reveal Mechanisms of Adaptation to Changing Environment Authors: Lee, Hyoungseok Tue, 28 Feb 2023 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/15165 2023-02-28T00:00:00Z https://repository.kopri.re.kr/handle/201206/14501 Title: The Revision of Lichen Flora Around Maxwell Bay, King George Island, Maritime Antarctic Authors: So, Jae Eun; Halda Josef P. P.; Hong, Soon Gyu; Hur Jae-Seoun; Kim, Ji Hee Abstract: Since the floristic study of lichens at the Barton and Weaver Peninsulas of King George Island in 2006, there have been intense investigations of the lichen flora of the two peninsulas as well as that of Fildes Peninsula and Ardley Island in Maxwell Bay, King George Island, South Shetland Islands, maritime Antarctic. In this study, a total of 104 species belonging to 53 genera, are identified from investigations of lichens that were collected in austral summer seasons from 2008 to 2016. Phenotypic and molecular analyses were incorporated for taxonomic identification. In particular, 31 species are found to be endemic to the Antarctic and 22 species are newly recorded to the Maxwell Bay region. Lepra dactylina, Stereocaulon caespitosum, and Wahlenbergiella striatula are newly recorded in the Antarctic, and the previously reported taxon Cladonia furcata is excluded from the formerly recorded list due to misidentification. We also provide ecological and geographical information about lichen associations and habitat preferences. Sun, 01 Jan 2023 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/14501 2023-01-01T00:00:00Z