An Evaluation on contribution of organo-metal complexes to enhanced soil CO release during drying-rewetting cycles using buried humic horizon soils

Suzuki, Yuri*; Hiradate, Shuntaro*; Koarashi, Jun   ; Atarashi-Andoh, Mariko  ; Suzuki, Kazuki*; Nakayama, Masataka*; Abe, Yukiko*; Hikosaka, Koki*; Kajino, Hirofumi*; Sase, Hiroyuki*; Urakawa, Rieko*; Nagano, Hirohiko*

Global warming is changing precipitation patterns, leading to more intense drying-rewetting cycles (DWCs) and impacting soil carbon (C). While microbially-derived C is traditionally considered the primary CO source during DWCs, C released from organo-metal complexes is increasingly recognized as significant. This study investigated the role of these complexes in DWC-induced CO release using soils with contrasting complex concentrations and microbial biomass. DWCs consistently increased CO release, with buried soils showing a much larger increase than surface soils. Changes in bacterial/archaeal and fungal communities due to DWCs were also observed. These findings suggest organo-metal complexes are key C sources during DWCs, potentially influencing soil microbial communities.