Flooding increases plant-derived carbon accumulation in soils of aquatic-terrestrial ecotone

Yiguo Ran; Ziqiang Mao; Hanzhong Jia; Xianjing He; Shaopan Xia; Fei Ye; Chamindra L Vithana; Siyue Li; Shengjun Wu; Ping Huang

doi:10.1016/j.jenvman.2024.123464

Flooding increases plant-derived carbon accumulation in soils of aquatic-terrestrial ecotone

J Environ Manage. 2024 Nov 27:373:123464. doi: 10.1016/j.jenvman.2024.123464. Online ahead of print.

Authors

Yiguo Ran¹, Ziqiang Mao², Hanzhong Jia³, Xianjing He⁴, Shaopan Xia⁵, Fei Ye⁶, Chamindra L Vithana⁷, Siyue Li⁸, Shengjun Wu⁹, Ping Huang¹⁰

Affiliations

¹ State Key Laboratory of Water Security for Lake and Watershed, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China. Electronic address: ranyiguo@cigit.ac.cn.
² State Key Laboratory of Water Security for Lake and Watershed, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China; Chongqing School, University of China Academy of Sciences, Chongqing, 400714, China.
³ College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, China.
⁴ Laboratoire des Sciences du Climat et de l'Environnement, IPSL-LSCE, CEA/CNRS/UVSQ, Gif sur Yvette, 91191, France.
⁵ Institute of Resource, Ecosystem and Environment of Agriculture, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
⁶ Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou, 510006, China.
⁷ Faculty of Science and Engineering, Southern Cross University, Military Road, East Lismore, NSW, 2480, Australia.
⁸ School of Environmental Ecology and Biological Engineering, Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, Wuhan Institute of Technology, Wuhan, 430205, China.
⁹ State Key Laboratory of Water Security for Lake and Watershed, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China.
¹⁰ State Key Laboratory of Water Security for Lake and Watershed, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China. Electronic address: huangping@cigit.ac.cn.

PMID: 39608241
DOI: 10.1016/j.jenvman.2024.123464

Abstract

Soils in the aquatic-terrestrial zone undergo periodic flooding and act as significant carbon sinks. However, the mechanisms governing soil organic carbon (SOC) formation in these zones are not well understood. This study elucidates the effects of periodic flooding on SOC accumulation at the water level drawdown zone of the Three Gorges Reservoir, using lignin phenols and amino sugars as indicators of plant- and microbial-derived carbon. Results showed that SOC content averaged at 7.52, 8.31, and 8.76 g kg^-1 in 0-20 cm soils at low, intermediate, and high flooding levels, respectively, compared to 5.87 g kg^-1 in control soils. Total lignin phenols and amino sugars averaged at 0.351, 0.377, 0.337 g kg^-1 and 0.697, 0.718, 0.756 g kg^-1 in 0-20 cm soils at high, intermediate, and low flooding levels, respectively, compared to 0.161 and 0.624 g kg^-1 in control soils. Similar patterns were observed in 20-40 cm soils. Periodic flooding significantly enhanced the accumulation of plant-derived carbon and its contribution to SOC accumulation by decreasing lignin phenol oxidation, while microbial-derived carbon contribution remained unaffected. Ratios of cinnamyl to vanillyl (1.13 in flooded soils vs. 1.08 in control) and syringyl to vanillyl (0.20 in flooded soils vs. 0.17 in control) indicated that lignin phenols originated primarily from woody angiosperms and remained stable. Flooding also modified edaphic variables, such as clay mineral and particle feature, enhancing organic compound accumulation. Clay minerals, particularly chlorite and kaolinite, played more pivotal roles than illite in regulating SOC accumulation. These findings underscore the potential for managing flooding regimes as a strategy to enhance carbon sequestration and improve ecosystem resilience in aquatic-terrestrial zones.

Keywords: Amino sugar; Clay minerals; Lignin phenol; Soil organic carbon; Water-level drawdown zone.