Effects of different emergent macrophytes on methane flux and rhizosphere microbial communities in wetlands

Qisheng Li; Hongyang Deng; Rujia He; Siwen Hu; Lijie Sun; Mengyuan Li; Qinglong L Wu; Jin Zeng

doi:10.1016/j.scitotenv.2024.172565

Effects of different emergent macrophytes on methane flux and rhizosphere microbial communities in wetlands

Sci Total Environ. 2024 Apr 19:932:172565. doi: 10.1016/j.scitotenv.2024.172565. Online ahead of print.

Authors

Qisheng Li¹, Hongyang Deng¹, Rujia He², Siwen Hu², Lijie Sun², Mengyuan Li³, Qinglong L Wu⁴, Jin Zeng⁵

Affiliations

¹ State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; The National Key Laboratory of Water Disaster Prevention, Hohai University, Nanjing 210098, China.
³ State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China.
⁴ State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Sino-Danish Centre for Education and Research, University of Chinese Academy of Sciences, Beijing 100039, China; Center for Evolution and Conservation Biology, Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China.
⁵ State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Sino-Danish Centre for Education and Research, University of Chinese Academy of Sciences, Beijing 100039, China; Poyang Lake Wetland Research Station, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Jiujiang 332899, China. Electronic address: jzeng@niglas.ac.cn.

PMID: 38642750
DOI: 10.1016/j.scitotenv.2024.172565

Abstract

Emergent macrophytes are of great importance for the structure and functioning of wetland ecosystems and play a significant role in environmental improvement, element cycling, and greenhouse gas (GHG) emissions. However, our understanding of how GHG fluxes differ among macrophyte species and its links with the microbial communities remain limited. In this study, we investigated the rhizosphere microbial communities (including total bacteria, methanotrophs, and methanogens) and the GHG fluxes associated with four emergent macrophytes-Phragmites australis, Thalia dealbata, Pontederia cordata, and Zizania latifolia-collected from Xuanwu Lake wetland, China. We observed the highest CH₄ flux (FCH₄) (9.35 ± 2.52 mg·m^-2·h^-1) from Z. latifolia zone, followed by P. australis, P. cordata, and T. dealbata zones (5.38 ± 1.63, 2.38 ± 2.91, and 2.02 ± 0.69 mg·m^-2·h^-1, respectively). Methanogenesis was methylotrophic at all sites, as the ¹³C-CH₄ values were higher than -64 ‰ and the fractionation coefficients were lower than 1.055. We found a positive linear relationship between FCH₄ and the methanogen community, in particular the relative abundances of Methanobacterium and Methanosarcina, indicating that the variations in FCH₄ among the studied macrophyte-dominated zones might be attributed to the differences in rhizosphere microbial communities. The methane emissions in various macrophyte zones might be due to the higher capacity of methanogenesis compared to methane oxidation which was inhibited by nutrient-rich sediments. Our findings provide insights for selecting specific emergent macrophytes characterized by low FCH₄ in wetland ecological restoration.

Keywords: Emergent macrophytes; Methane; Methanogens; Methanotrophs; Rhizosphere microbes; Wetlands.