Denitrification dynamics in unsaturated soils with different porous structures and water saturation degrees: A focus on the shift in microbial community structures

Sungjik Oh, Kyungjin Cho, Saerom Park, Man Jae Kwon, Jaeshik Chung, Seunghak Lee

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

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.

Original languageEnglish
Article number130413
JournalJournal of hazardous materials
Volume445
DOIs
Publication statusPublished - 2023 Mar 5

Bibliographical note

Funding Information:
Funding: This work was supported by the Korea Environment Industry & Technology Institute (KEITI) through the Subsurface Environment Management (SEM) Project ( 2018002440006 ) funded by the Korea Ministry of Environment (MOE), the National Research Foundation of Korea (NRF) through the ‘Climate Change Impact Minimizing Technology’ Program, funded by the Korean Ministry of Science and ICT(MSIT) (2020M3H5A1080712). The authors also acknowledge the support from the Future Research Program (2E31932), funded by the Korea Institute of Science and Technology (KIST). S. Lee was partly supported by the KU-KIST Graduate School Project .

Publisher Copyright:
© 2022 The Authors

Keywords

  • Denitrification
  • Microbial community structure
  • Nitrate
  • Uniformity coefficient
  • Vadose zone
  • Water saturation degree

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis

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