오성직 조경진 Park, Saerom Kwon, Man Jae Chung, Jaeshik Lee, Seunghak 2024-01-12T02:31:41Z 2024-01-12T02:31:41Z 2023-01-17 2023-03 0304-3894 https://pubs.kist.re.kr/handle/201004/75779 Despite its environmental significance, little is known about denitrification in vadose zones owing to the complexity of such environments. Here, we investigated denitrification in unsaturated soils with different pore distributions. To this end, we performed batch-type denitrification experiments and analyzed microbial community shifts before and after possible reactions with nitrates to clarify the relevant denitrifying mechanism in the microcosms. For quantitative comparison, pore distribution in the test soil samples was characterized based on the uniformity coefficient (Cu) and water saturation degree (SD). Micro-CT analysis of the soil pore distribution confirmed that the proportion of bigger-sized pores increased with decreasing Cu. However, oxygen diffusion into the system was controlled by SD rather than Cu. Within a certain SD range (51？67%), the pore condition changed abruptly from an oxic to an anoxic state. Consequently, denitrification occurred even under unsaturated soil conditions when the SD increased beyond 51？67%. High throughput sequencing revealed that the same microbial species were potentially responsible for denitrification under both partially (SD 67%), and fully saturated (SD of 100%) conditions, implying that the mechanism of denitrification in a vadose zone, if it exists, might be possibly similar under varying conditions. English Elsevier BV Denitrification dynamics in unsaturated soils with different porous structures and water saturation degrees: A focus on the shift in microbial community structures Article 10.1016/j.jhazmat.2022.130413 1 Journal of Hazardous Materials, v.445 Journal of Hazardous Materials 445 Y scie scopus 000903584100004 Engineering, Environmental Environmental Sciences Engineering Environmental Sciences & Ecology Article SP-NOV. BACTERIAL NITRATE NITRIFICATION GROUNDWATER PERFORMANCE FERTILIZER TRANSPORT SYSTEM Vadose zone Nitrate Denitrification Uniformity coefficient Water saturation degree Microbial community structure