Weathering extents and anthropogenic influences shape the soil bacterial community along a subsurface zonation

Han Suk Kim, Kanghyun Park, Ho Young Jo, Man Jae Kwon

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Subsurface environments are composed of various active soil layers with dynamic biogeochemical interactions. We investigated soil bacterial community composition and geochemical properties along a vertical soil profile, which was categorized into surface, unsaturated, groundwater fluctuated, and saturated zones, in a testbed site formerly used as farmland for several decades. We hypothesized that weathering extent and anthropogenic inputs influence changes in the community structure and assembly processes and have distinct contributions along the subsurface zonation. Elemental distribution in each zone was strongly affected by the extent of chemical weathering. A 16S rRNA gene analysis indicated that bacterial richness (alpha diversity) was highest in the surface zone, and also higher in the fluctuated zone, than in unsaturated and saturated zones due to the effects of high organic matter, high nutrient levels, and/or aerobic conditions. Redundancy analysis showed that major elements (P, Na), a trace element (Pb), NO3, and the weathering extent were key driving forces shaping bacterial community composition along the subsurface zonation. Assembly processes were governed by specific ecological niches, such as homogeneous selection, in the unsaturated, fluctuated, and saturated zones, while in the surface zone, they were dominated by dispersal limitation. These findings together suggest that the vertical variation in soil bacterial community assembly is zone-specific and shaped by the relative influences of deterministic vs. stochastic processes. Our results provide novel insights into the relationships between bacterial communities, environmental factors, and anthropogenic influences (e.g., fertilization, groundwater, soil contamination), and into the roles of specific ecological niches and subsurface biogeochemical processes in these relationships.

Original languageEnglish
Article number162570
JournalScience of the Total Environment
Volume876
DOIs
Publication statusPublished - 2023 Jun 10

Bibliographical note

Funding Information:
We would like to thank many researchers in the SMART SEM research center for helping with the laboratory analysis. This work was supported by the Korea Environmental Industry and Technology Institute through the Subsurface Environment Management Project, funded by the Korea Ministry of Environment (grant number 2018002440002 ). MJK was partly supported by the Korea University Grant. Authors thank Ph.D. Dayi Zhang (Tsinghua Univ.) for assisting the analysis of microbial assembly process.

Publisher Copyright:
© 2023 Elsevier B.V.

Keywords

  • Anthropogenic influences
  • Ecological assembly process
  • Soil bacterial community
  • Soil core analysis
  • Subsurface zonation

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

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