Temperature and organic carbon quality control the anaerobic carbon mineralization in peat profiles via modulating microbes: A case study of Changbai Mountain

Hongyan Wang; Yijie Xu; Amit Kumar; Klaus-Holger Knorr; Xiaoning Zhao; Jeffrey Paulo H Perez; Guoxin Sun; Zhi-Guo Yu

doi:10.1016/j.envres.2023.116904

Temperature and organic carbon quality control the anaerobic carbon mineralization in peat profiles via modulating microbes: A case study of Changbai Mountain

Environ Res. 2023 Nov 15;237(Pt 1):116904. doi: 10.1016/j.envres.2023.116904. Epub 2023 Aug 16.

Authors

Hongyan Wang¹, Yijie Xu², Amit Kumar², Klaus-Holger Knorr³, Xiaoning Zhao⁴, Jeffrey Paulo H Perez⁵, Guoxin Sun⁶, Zhi-Guo Yu⁷

Affiliations

¹ School of Hydrology and Water Resources, Nanjing University of Information Science and Technology, Nanjing, 210044, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua, 321004, China; State Key Lab of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
² School of Hydrology and Water Resources, Nanjing University of Information Science and Technology, Nanjing, 210044, China.
³ University of Münster, Institute for Landscape Ecology, Ecohydrology and Biogeochemistry Group, Heisenbergstr. 2, Münster, 48149, Germany.
⁴ School of Geographical Sciences, Nanjing University of Information Science and Technology, Nanjing, 210044, China.
⁵ Sec. 3.2 Organic Geochemistry, GFZ German Research Centre for Geosciences, Telegrafenberg, 14473, Potsdam, Germany.
⁶ State Key Lab of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
⁷ School of Hydrology and Water Resources, Nanjing University of Information Science and Technology, Nanjing, 210044, China. Electronic address: zhiguo.yu@nuist.edu.cn.

PMID: 37595828
DOI: 10.1016/j.envres.2023.116904

Abstract

Peatlands account for a significant fraction of the global carbon stock. However, the complex interplay of abiotic and biotic factors governing anaerobic carbon mineralization in response to warming remains unclear. In this study, peat sediments were collected from a typical northern peatland-Changbai Mountain to investigate the behavior and mechanism of anaerobic carbon mineralization in response to depth (0-200 cm) and temperature (5 °C, 15 °C and 20 °C), by integrating geochemical and microbial analysis. Several indices including humification indexes (HI), aromaticity, and water extractable organic carbon (WEOC) components were applied to evaluate carbon quality, while 16S rRNA sequencing was used to measure microbial composition. Regardless of temperature, degradations of carbon quality and associated reduction in microbial abundance as well as diversity resulted in a decrease in anaerobic carbon mineralization (both CO₂ and CH₄) towards greater depth. Warming either from 5 °C to 15 °C or 20 °C significantly increased anaerobic carbon mineralization in all depth profiles by improving carbon availability. Enhanced carbon availabilities were mediated by the change in microbial composition (p < 0.01) and an increase in metabolic activities, which was particularly evident in the enhanced β-glucosidase activity and microbial collaborations. A remarkable increase of over 10-fold in the relative abundance of the Geothrix genus was observed under warming. Overall, warming resulted in an enhanced contribution of CH₄ emission and a higher ratio of hydrogenotrophic methanogenesis, as evidenced by carbon isotope fractionation factors. In addition, deep peat soils (>100 cm) with recalcitrant carbon demonstrated greater temperature sensitivity (Q₁₀: ∼2.0) than shallow peat soils (Q₁₀:∼1.2) when temperature increased from 15 °C to 20 °C. The findings of this study have significantly deepened our understanding for mechanisms of carbon quality and microbe-driven anaerobic carbon mineralization in peatlands under global warming.

Keywords: Anaerobic carbon mineralization; Carbon quality; Microbe; Peat profiles; Temperature.