Spatiotemporal dynamics of dissolved organic carbon in a subtropical wetland and their implications for methane emissions

Yiming Zhang; Xianyu Huang; Zhiqing Zhang; Jerome Blewett; B D A Naafs

doi:10.1016/j.geoderma.2022.115876

Spatiotemporal dynamics of dissolved organic carbon in a subtropical wetland and their implications for methane emissions

Yiming Zhang, Xianyu Huang^*, Zhiqing Zhang, Jerome Blewett, B D A Naafs

^*Corresponding author for this work

Research output: Contribution to journal › Article (Academic Journal) › peer-review

19 Citations (Scopus)

66 Downloads (Pure)

Abstract

Wetlands represent about one-third of the global soil organic carbon storage and are the largest natural source of atmospheric methane, a powerful greenhouse gas. Understanding the factors that influence the carbon dynamics in wetlands, and their influence on methane emission, is therefore important. Dissolved organic carbon (DOC) is a major form of carbon export from wetlands and plays an essential role in the aquatic carbon cycling process. However, constraints on spatial and temporal dynamics of DOC in vertical peat layers and their relationship to wetland methane emissions are still rare. Here we investigated spatiotemporal changes in porewater DOC concentration and optical properties (SUVA254, E2/E3, E4/E6) in surface (0–10 cm) and deep (20–30 cm, 50–60 cm, 100–110 cm) peat layers in a subtropical wetland complex, central China, with the aim to explore DOC dynamics and their relationship to methane emissions from wetlands. DOC dynamics and environmental controls were investigated in the context of high-resolution environmental monitoring, including air temperature, rainfall, water table depth, water chemistry, and methane emissions. DOC of surface peat layers generally had higher concentrations, higher aromaticity, lower humification, and greater temporal variations compared to deeper peat layers. During summer floods and high water table conditions, DOC concentrations in the surface peat increased significantly, whilst DOC exports from rivers and lakes also increased synchronously. In contrast, DOC concentrations and spectral properties of deep peat layers remained constant across the sampling months and water table fluctuations. Methane emissions were positively correlated with air temperature and DOC concentration in the porewater of surface peat layers, and negatively correlated with water table depth. Our results suggest that DOC concentration in the porewater of surface peat layers may also have affected the flux of methane emission from wetlands.

Original language	English
Article number	115876
Number of pages	14
Journal	Geoderma
Volume	419
Early online date	12 Apr 2022
DOIs	https://doi.org/10.1016/j.geoderma.2022.115876
Publication status	Published - 1 Aug 2022

Bibliographical note

Funding Information:
This work was supported by the National Natural Science Foundation of China ( U20A2094 , 91951208 ), and the Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan) (CUG170103). Jiantao Xue, Bingyan Zhao, Yang Yang, Meiling Zhao, Xiaofang Yu, Dongxiang Wang and Ruicheng Wang are thanked for their help in the field and laboratory analyses. BDAN acknowledges funding through a Royal Society Tata University Research Fellowship. We thank two anonymous reviewers for their constructive comments that greatly improved the quality of this manuscript.

Publisher Copyright:
© 2022 Elsevier B.V.

Keywords

wetland
dissolved organic carbon
Water table level
VERTICAL PROFILES
Methane emissions

Access to Document

10.1016/j.geoderma.2022.115876

Full-text PDF (author accepted manuscript)
This is the accepted author manuscript (AAM). The final published version (version of record) is available online via Elsevier at https://doi.org/10.1016/j.geoderma.2022.115876. Please refer to any applicable terms of use of the publisher.
Accepted author manuscript, 2.24 MBLicence: CC BY-NC-ND

Handle.net

Persistent link

Cite this

@article{5baab68bc4424ad1b346537743659183,

title = "Spatiotemporal dynamics of dissolved organic carbon in a subtropical wetland and their implications for methane emissions",

abstract = "Wetlands represent about one-third of the global soil organic carbon storage and are the largest natural source of atmospheric methane, a powerful greenhouse gas. Understanding the factors that influence the carbon dynamics in wetlands, and their influence on methane emission, is therefore important. Dissolved organic carbon (DOC) is a major form of carbon export from wetlands and plays an essential role in the aquatic carbon cycling process. However, constraints on spatial and temporal dynamics of DOC in vertical peat layers and their relationship to wetland methane emissions are still rare. Here we investigated spatiotemporal changes in porewater DOC concentration and optical properties (SUVA254, E2/E3, E4/E6) in surface (0–10 cm) and deep (20–30 cm, 50–60 cm, 100–110 cm) peat layers in a subtropical wetland complex, central China, with the aim to explore DOC dynamics and their relationship to methane emissions from wetlands. DOC dynamics and environmental controls were investigated in the context of high-resolution environmental monitoring, including air temperature, rainfall, water table depth, water chemistry, and methane emissions. DOC of surface peat layers generally had higher concentrations, higher aromaticity, lower humification, and greater temporal variations compared to deeper peat layers. During summer floods and high water table conditions, DOC concentrations in the surface peat increased significantly, whilst DOC exports from rivers and lakes also increased synchronously. In contrast, DOC concentrations and spectral properties of deep peat layers remained constant across the sampling months and water table fluctuations. Methane emissions were positively correlated with air temperature and DOC concentration in the porewater of surface peat layers, and negatively correlated with water table depth. Our results suggest that DOC concentration in the porewater of surface peat layers may also have affected the flux of methane emission from wetlands.",

keywords = "wetland, dissolved organic carbon, Water table level, VERTICAL PROFILES, Methane emissions",

author = "Yiming Zhang and Xianyu Huang and Zhiqing Zhang and Jerome Blewett and Naafs, {B D A}",

note = "Funding Information: This work was supported by the National Natural Science Foundation of China ( U20A2094 , 91951208 ), and the Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan) (CUG170103). Jiantao Xue, Bingyan Zhao, Yang Yang, Meiling Zhao, Xiaofang Yu, Dongxiang Wang and Ruicheng Wang are thanked for their help in the field and laboratory analyses. BDAN acknowledges funding through a Royal Society Tata University Research Fellowship. We thank two anonymous reviewers for their constructive comments that greatly improved the quality of this manuscript. Publisher Copyright: {\textcopyright} 2022 Elsevier B.V.",

year = "2022",

month = aug,

day = "1",

doi = "10.1016/j.geoderma.2022.115876",

language = "English",

volume = "419",

journal = "Geoderma",

issn = "0016-7061",

publisher = "Elsevier B.V.",

}

TY - JOUR

T1 - Spatiotemporal dynamics of dissolved organic carbon in a subtropical wetland and their implications for methane emissions

AU - Zhang, Yiming

AU - Huang, Xianyu

AU - Zhang, Zhiqing

AU - Blewett, Jerome

AU - Naafs, B D A

N1 - Funding Information: This work was supported by the National Natural Science Foundation of China ( U20A2094 , 91951208 ), and the Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan) (CUG170103). Jiantao Xue, Bingyan Zhao, Yang Yang, Meiling Zhao, Xiaofang Yu, Dongxiang Wang and Ruicheng Wang are thanked for their help in the field and laboratory analyses. BDAN acknowledges funding through a Royal Society Tata University Research Fellowship. We thank two anonymous reviewers for their constructive comments that greatly improved the quality of this manuscript. Publisher Copyright: © 2022 Elsevier B.V.

PY - 2022/8/1

Y1 - 2022/8/1

N2 - Wetlands represent about one-third of the global soil organic carbon storage and are the largest natural source of atmospheric methane, a powerful greenhouse gas. Understanding the factors that influence the carbon dynamics in wetlands, and their influence on methane emission, is therefore important. Dissolved organic carbon (DOC) is a major form of carbon export from wetlands and plays an essential role in the aquatic carbon cycling process. However, constraints on spatial and temporal dynamics of DOC in vertical peat layers and their relationship to wetland methane emissions are still rare. Here we investigated spatiotemporal changes in porewater DOC concentration and optical properties (SUVA254, E2/E3, E4/E6) in surface (0–10 cm) and deep (20–30 cm, 50–60 cm, 100–110 cm) peat layers in a subtropical wetland complex, central China, with the aim to explore DOC dynamics and their relationship to methane emissions from wetlands. DOC dynamics and environmental controls were investigated in the context of high-resolution environmental monitoring, including air temperature, rainfall, water table depth, water chemistry, and methane emissions. DOC of surface peat layers generally had higher concentrations, higher aromaticity, lower humification, and greater temporal variations compared to deeper peat layers. During summer floods and high water table conditions, DOC concentrations in the surface peat increased significantly, whilst DOC exports from rivers and lakes also increased synchronously. In contrast, DOC concentrations and spectral properties of deep peat layers remained constant across the sampling months and water table fluctuations. Methane emissions were positively correlated with air temperature and DOC concentration in the porewater of surface peat layers, and negatively correlated with water table depth. Our results suggest that DOC concentration in the porewater of surface peat layers may also have affected the flux of methane emission from wetlands.

AB - Wetlands represent about one-third of the global soil organic carbon storage and are the largest natural source of atmospheric methane, a powerful greenhouse gas. Understanding the factors that influence the carbon dynamics in wetlands, and their influence on methane emission, is therefore important. Dissolved organic carbon (DOC) is a major form of carbon export from wetlands and plays an essential role in the aquatic carbon cycling process. However, constraints on spatial and temporal dynamics of DOC in vertical peat layers and their relationship to wetland methane emissions are still rare. Here we investigated spatiotemporal changes in porewater DOC concentration and optical properties (SUVA254, E2/E3, E4/E6) in surface (0–10 cm) and deep (20–30 cm, 50–60 cm, 100–110 cm) peat layers in a subtropical wetland complex, central China, with the aim to explore DOC dynamics and their relationship to methane emissions from wetlands. DOC dynamics and environmental controls were investigated in the context of high-resolution environmental monitoring, including air temperature, rainfall, water table depth, water chemistry, and methane emissions. DOC of surface peat layers generally had higher concentrations, higher aromaticity, lower humification, and greater temporal variations compared to deeper peat layers. During summer floods and high water table conditions, DOC concentrations in the surface peat increased significantly, whilst DOC exports from rivers and lakes also increased synchronously. In contrast, DOC concentrations and spectral properties of deep peat layers remained constant across the sampling months and water table fluctuations. Methane emissions were positively correlated with air temperature and DOC concentration in the porewater of surface peat layers, and negatively correlated with water table depth. Our results suggest that DOC concentration in the porewater of surface peat layers may also have affected the flux of methane emission from wetlands.

KW - wetland

KW - dissolved organic carbon

KW - Water table level

KW - VERTICAL PROFILES

KW - Methane emissions

U2 - 10.1016/j.geoderma.2022.115876

DO - 10.1016/j.geoderma.2022.115876

M3 - Article (Academic Journal)

SN - 0016-7061

VL - 419

JO - Geoderma

JF - Geoderma

M1 - 115876

ER -

Spatiotemporal dynamics of dissolved organic carbon in a subtropical wetland and their implications for methane emissions

Abstract

Bibliographical note

Keywords

Access to Document

Handle.net

Fingerprint

Cite this