https://repository.kopri.re.kr/handle/201206/9786 Sun, 05 Apr 2026 19:21:19 GMT 2026-04-05T19:21:19Z https://repository.kopri.re.kr/handle/201206/16004 Title: A study of Arctic Microbial Community Structure Response to Increased Temperature and Precipitation by Phospholipid Fatty Acid Analysis Authors: Nam, Sungjin; Jung, Ji Young Abstract: Climate change is more rapid in the Arctic than elsewhere in the world, and increased precipitation and warming are expected cause changes in biogeochemical processes due to altered microbial communities and activities. It is crucial to investigate microbial responses to climate change to understand changes in carbon and nitrogen dynamics. We investigated the effects of increased temperature and precipitation on microbial biomass and community structure in dry tundra using two depths of soil samples (organic and mineral layers) under four treatments (control, warming, increased precipitation, and warming with increased precipitation) during the growing season (June-September) in Cambridge Bay, Canada (69°N, 105°W). A phospholipid fatty acid (PLFA) analysis method was applied to detect active microorganisms and distinguish major functional groups (e.g., fungi and bacteria) with different roles in organic matter decomposition. The soil layers featured different biomass and community structure; ratios of fungal/bacterial and gram-positive/-negative bacteria were higher in the mineral layer, possibly connected to low substrate quality. Increased temperature and precipitation had no effect in either layer, possibly due to the relatively short treatment period seven years) or the ecosystem type. Mostly, sampling times did not affect PLFAs in the organic layer, but June mineral soil samples showed higher contents of total PLFAs and PLFA biomarkers for bacteria and fungi than those in other months. Despite the lack of response found in this investigation, long-term monitoring of these communities should be maintained because of the slow response times of vegetation and other parameters in high-Arctic ecosystems. Sun, 01 Jan 2023 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/16004 2023-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/10877 Title: Dynamics of microbial communities and CO2 and CH4 fluxes in the tundra ecosystems of the changing Arctic Authors: Kwon, Min Jung; Jung, Ji Young; Tripathi, Binu M.; Gockede, Mathias; Lee, Yoo Kyung; Kim, Mincheol Abstract: Arctic tundra ecosystems are rapidly changing due to the amplified effects of global warming within the northern high latitudes. Warming has the potential to increase the thawing of the permafrost and to change the landscape and its geochemical characteristics, as well as terrestrial biota. It is important to investigate microbial processes and community structures, since soil microorganisms play a significant role in decomposing soil organic carbon in the Arctic tundra. In addition, the feedback from tundra ecosystems to climate change, including the emission of greenhouse gases into the atmosphere, is substantially dependent on the compositional and functional changes in the soil microbiome. This article reviews the current state of knowledge of the soil microbiome and the two most abundant greenhouse gas (CO2 and CH4) emissions, and summarizes permafrost thaw-induced changes in the Arctic tundra. Furthermore, we discuss future directions in microbial ecological research coupled with its link to CO2 and CH4 emissions. Wed, 01 May 2019 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/10877 2019-05-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/10865 Title: Biogeochemical evidence of anaerobic methane oxidation on active submarine mud volcanoes on the continental slope of the Canadian Beaufort Sea Authors: Lee, Dong-Hun; Kim, Junghyun; Lee, Yung Mi; Stadnitskaia, Alina; Jin, Young Keun; Niemann, Helge; Kim, Young-Gyun; Shin, Kyung-Hoon Abstract: TS2In this study, we report lipid biomarker patterns and phylogenetic identities of key microbial communities mediating anaerobic oxidation of methane (AOM)in active mud volcanoes (MVs) on the continental slope of the Canadian Beaufort Sea. The carbon isotopic compositions (d13C) of sn-2- and sn-3-hydroxyarchaeol showed the highly 13C-depleted values (-114‰ to -82 ‰) associated with a steep depletion in sulfate concentrations within 0.7m of sediment depths. This suggested the presence of methan otrophic archaea involved in sulfate-dependent AOM, albeit in a small amount. The ratio of sn-2-hydroxyarchaeol to archaeol (> 1) and operational taxonomic units (OTUs) indicated that archaea of the anaerobic methanotrophic archaea (ANME) CE2 clades ANME-2c and ANME-3 were 15 involved in AOM. Higher d13C values of archaeol and biphytanes (BPs; -55.2+/-10.0‰ and -39.3+/-13.0 ‰, respectively) suggested that archaeal communities were also assimilating AOM-derived inorganic carbon. Furthermore, the distinct distribution patterns of methanotrophs in the three MVs appears to be associated with varying intensities of ascending gas fluids. Consequently, our results suggest that the niche diversification of active mud volcanoes has shaped distinct archaeal communities that play important roles in AOM in the Beaufort Sea. Sat, 01 Dec 2018 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/10865 2018-12-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/10855 Title: Laboratory examination of greenhouse gaseous and microbial dynamics during thawing of frozen soil core collected from a black spruce forest in Interior Alaska Authors: Nagano, Hirohiko; Kim, Yongwon; Lee, Bang Yong; Shigeta, Haruka; Inubushi, Kazuyuki Abstract: In this study, we conducted an incubation experiment on a frozen soil core collected from a black spruce forest in Interior Alaska, in order to investigate potential changes in greenhouse gaseous (GHG) and microbial dynamics during thawing of frozen soil. The soil thawing is an important environmental process determining the annual GHG balance in the northern high-latitude ecosystem. A core spanning the ground surface to upper permafrost with a depth of 90 cm was vertically grouped into three layers (top, middle, and bottom layers). Then, 12 soil samples from 3 layers (i.e., 4 soil samples per layer) were incubated for 3 weeks, and net carbon dioxide (CO2) and methane (CH4) release/uptake rates were estimated. During the incubation, temperature was changed weekly from 0 to 5, then 10°C. The net amounts of CO2 released by six of the eight soil samples from the top and middle layers were 1.5？19.2- fold greater at 5°C than at 0°C, while the release at 10°C was reduced in the cases of three of these six soil samples. Net CH4 release was the greatest in bottom-layer soil samples incubated at 0°C. Then, low but apparent CH4 release was observed in top and middle-layer soil samples incubated at 0°C. At 5 and 10°C, net CH4 release from bottom-layer soil samples was decreased. Then, net CH4 uptake was observed in the top and the middle-layer soil samples. Both net uptake and release of CH4 were reduced upon the addition of a chemical inhibitor (i.e., 2-bromoethane sulfonate) of anaerobic methanotrophic and methanogenic activity. The bacterial and archaeal community structures based on 16S rRNA amplicon analysis were changed along the depth, while they were less changed during thawing. Thus, it was found that soil GHG dynamics responded sensitively and variously to thawing, while there was less change in 16S rRNA-based microbial community structures during the thawing progress. Thu, 01 Nov 2018 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/10855 2018-11-01T00:00:00Z