RESEARCH ARTICLE

Benthic bioturbations weaken the stability of blue carbon storage

¹ School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
² Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China
³ Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Fujian Key Laboratory of Coastal Pollution Prevention and Control, College of the Environment & Ecology, Xiamen University, Xiamen 361102, China
⁴ Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen 318055, China
⁵ Center for Turbulence Research, Stanford University, Stanford, CA 94305, USA
⁶ Eastern Institute for Advanced Study, Eastern Institute of Technology, Ningbo 315200, China
⁷ Department of Ocean Science, and Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong 999077, China
⁸ Hubei Key Laboratory of Multi-Media Pollution Cooperative Control in Yangtze Basin, School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
⁹ School of Geography and Tourism, Huizhou University, Huizhou 516007, China
¹⁰ State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710061, China
¹¹ Faculty of Science and Engineering, Southern Cross University, Lismore, New South Wales 2480, Australia
¹² CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China

^* Corresponding authors (emails: liuy8@sustech.edu.cn (Yan Liu); wangk3@sustech.edu.cn (Kai Wang); kxiao@yic.ac.cn (Kai Xiao))

Received: 26 September 2024
Revised: 25 November 2024
Accepted: 16 December 2024

Abstract

Coastal ecosystems are known for their ability to sequester organic carbon (OC), termed “blue carbon”. The molecular composition of dissolved organic matter (DOM) can affect sediment OC content; however, the impact of benthic bioturbation on DOM properties and OC storage stability is not well understood. This study examined the effects of bioturbation by fiddler crabs on DOM molecular properties and OC storage stability along the Chinese coastline. These findings indicate that crab bioturbation enhanced the release of labile molecules by 59% on average. This increase is controlled by the coupling reactions of iron and manganese minerals, and is influenced by climatic gradients. Moreover, fiddler crab bioturbation diminishes the durability of blue carbon storage, with the most significant effects observed in mangrove forests, followed by bare mudflats, tidal creek banks, and saltmarshes. These results underscore the critical role of benthic bioturbation in global blue carbon budgets.