https://repository.kopri.re.kr/handle/201206/5359 2026-04-19T03:49:54Z 2026-04-19T03:49:54Z Kwon, Min Jung Jung, Ji Young Tripathi, Binu M. Gockede, Mathias Lee, Yoo Kyung Kim, Mincheol https://repository.kopri.re.kr/handle/201206/10877 2022-03-24T07:14:48Z 2019-05-01T00:00:00Z

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.

2019-05-01T00:00:00Z Lee, Dong-Hun Kim, Junghyun Lee, Yung Mi Stadnitskaia, Alina Jin, Young Keun Niemann, Helge Kim, Young-Gyun Shin, Kyung-Hoon https://repository.kopri.re.kr/handle/201206/10865 2022-03-24T07:14:17Z 2018-12-01T00:00:00Z

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.

2018-12-01T00:00:00Z Nagano, Hirohiko Kim, Yongwon Lee, Bang Yong Shigeta, Haruka Inubushi, Kazuyuki https://repository.kopri.re.kr/handle/201206/10855 2022-03-24T07:14:13Z 2018-11-01T00:00:00Z

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.

2018-11-01T00:00:00Z Park, Keunbo Kim, Dongwook Lee, Bang Yong Yang, Heekwon https://repository.kopri.re.kr/handle/201206/9527 2022-03-24T07:14:14Z 2018-10-01T00:00:00Z

Title: Development of Shallow-Depth Soil Temperature Estimation Model Based on Thermal Response in Permafrost Area Authors: Park, Keunbo; Kim, Dongwook; Lee, Bang Yong; Yang, Heekwon Abstract: A soil temperature estimation model for increasing depth in a permafrost area in Alaska near the Bering Sea is proposed based on a thermal response concept. Thermal response is a measure of the internal physical heat transfer of soil due to transferred heat into the soil. Soil temperature data at different depths from late spring to the early autumn period at multiple permafrost sites were collected using automatic sensor measurements. From the analysis results, a model was established based on the relationship between the normalized cumulative soil temperatures (CRCST*i,m and CST*ud,m) of two different depths. CST*ud,m is the parameter of the soil temperature measurement at a depth of 5 cm, and CRCST*i,m is the parameter of the soil temperature measured at deeper depths of i cm (i = 10, 15, 20, and 30). Additionally, the fitting parameters of the mathematical models of the CRCST*i,m？CST*ud,m relationship were determined. The measured soil temperature depth profiles at a different site were compared with their predicted soil temperatures using the developed model for the model validation purpose. Consequently, the predicted soil temperatures at different soil depths using the soil temperature measurement of the uppermost depth (5 cm) were in good agreement with the measured results.

2018-10-01T00:00:00Z