The spatial patterns and driving mechanisms of blue carbon 'loss' and 'gain' in a typical mangrove ecosystem: A case study of Beihai, Guangxi Province of China

Zhenxi Xie; Haonan Li; Yuan Yuan; Wei Hu; Gang Luo; Longtian Huang; Mo Chen; Weimei Wu; Guiling Yan; Xiang Sun

doi:10.1016/j.scitotenv.2023.167241

The spatial patterns and driving mechanisms of blue carbon 'loss' and 'gain' in a typical mangrove ecosystem: A case study of Beihai, Guangxi Province of China

Sci Total Environ. 2023 Dec 20:905:167241. doi: 10.1016/j.scitotenv.2023.167241. Epub 2023 Sep 21.

Authors

Zhenxi Xie¹, Haonan Li¹, Yuan Yuan¹, Wei Hu¹, Gang Luo¹, Longtian Huang¹, Mo Chen¹, Weimei Wu¹, Guiling Yan¹, Xiang Sun²

Affiliations

¹ College of Resources, Environment and Materials, Guangxi University, Guangxi, Nanning 530004, China.
² College of Resources, Environment and Materials, Guangxi University, Guangxi, Nanning 530004, China; Key Laboratory of Environmental Protection (Guangxi University), Education Department of Guangxi Zhuang Autonomous Region, Guangxi, Nanning 530004, China; Guangxi Key Laboratory of Emerging Contaminants Monitoring, Early Warning and Environmental Health Risk Assessment, Guangxi, Nanning 530004, China. Electronic address: sunxiangphd@gxu.edu.cn.

PMID: 37741412
DOI: 10.1016/j.scitotenv.2023.167241

Abstract

The role of mangroves in carbon sequestration is critical in mitigating climate change. For better identifying the carbon conservation hotspots of mangroves influenced by environmental factors, the spatial distribution and driving mechanisms of mangrove vegetation and soil carbon sequestration, as well as the future carbon dynamics of mangroves, required clarification. Firstly, we assessed the spatial pattern of vegetation biomass and soil depth-varied soil total organic carbon (TOC) in Xiaoguansha, Guangxi Province of China, and its relationships with duration of inundation (DTI) were explored. Additionally, the carbon storage capacity of adjacent mangrove tidal flats as potential carbon reservoirs was quantified. Thirdly, freshwater, and nutrient inputs, biotic factors of mangrove, and soil composition were selected as impact factors, and their mechanisms in carbon sequestration were elucidated by using Partial least squares path modeling (PLS-PM). Finally, medium values of environmental factors on mangrove carbon sequestration were revealed, based on which future loss and gain patterns of carbon sequestration under the combined effects were fully discussed. The results showed that: (1) The Above-ground biomass (AGB) and TOC densities were 32.89 Mg C/ha and 185.10 Mg C/ha in the study area, and both were enriched in the Interior areas. The carbon sequestration in the tidal flats was equivalented to >1/5 of total carbon sequestration of mangroves. (2) DTI was the most critical factor affecting the carbon sequestration pattern and was found to be positive correlated with AGB and TOC via changing soil contents (SC), whereas it exhibits a negative correlation with AGB and TOC through influencing canopy density (CD). CD and TP were identified as significant predictors. (3) Median analysis indicated that future carbon 'gain' area will move nearshore, whereas the carbon-rich intertidal area may undergo carbon loss. This study provided new insights and scientific understanding for management of mangrove blue carbon function.

Keywords: Biomass; Carbon loss and gain; Environmental variables; Mangroves; Soil organic carbon.