Yan Chuman, Li Qiunan, Wang Yasong, Li Xinxin, Baki Mohammad Abdul, Saha Shilpi, Zhou Jiaodi, Xu Yunping
College of Oceanography and Ecological Science, Shanghai Ocean University, Shanghai, 201306, China.
Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China.
Mar Environ Res. 2025 Sep;210:107323. doi: 10.1016/j.marenvres.2025.107323. Epub 2025 Jun 22.
Black carbon (BC) is produced by the incomplete combustion of biomass and fossil fuels and plays an important role in global climate change and carbon cycling. Mangroves, seagrass beds, and salt marshes are collectively recognized as the three major blue carbon systems. However, research on BC in mangroves remains limited. We investigated mangrove sediments from three regions, Hong Kong (HK), Guangxi (GX), and Bangladesh (BD). Using Chemical Thermal Oxidation (CTO-375) and Benzene Polycarboxylic Acids (BPCA) analytical methods, along with elemental analysis, stable carbon isotope (δC), and MixSIAR model source apportionment, we explored the content, source, and composition of BC in sediments from these three mangrove ecosystems. The results indicate that the BC content is the highest in HK, followed by BD and GX (0.18 ± 0.02 %, 0.11 ± 0.01 % and 0.05 ± 0.01 %, respectively), while the BC/Total Organic Carbon (TOC) ratio is the highest in BD, followed by GX and HK (0.18 ± 0.01, 0.14 ± 0.02 and 0.08 ± 0.01, respectively). The contributions of fossil fuel combustion to the mangrove sediments are in a decreasing order of HK (59.0 ± 0.3 %), BD (55.1 ± 1.3 %), and GX (50.0 ± 3.4 %). These spatial variabilities are related to the development levels and energy structures in surrounding areas. In HK mangrove sediments, BC may be more influenced by long-distance transport and has undergone more pronounced photodegradation prior to burial, resulting in the lowest aromaticity, as indicated by the (B5CA + B6CA)/BPCAs ratio. We demonstrated BC as an important but heterogeneous component of the carbon pool in mangrove sediments.
黑碳（BC）由生物质和化石燃料不完全燃烧产生，在全球气候变化和碳循环中起着重要作用。红树林、海草床和盐沼被公认为三大主要蓝碳系统。然而，关于红树林中黑碳的研究仍然有限。我们调查了来自香港（HK）、广西（GX）和孟加拉国（BD）三个地区的红树林沉积物。使用化学热氧化（CTO - 375）和苯多元羧酸（BPCA）分析方法，结合元素分析、稳定碳同位素（δC）和MixSIAR模型源解析，我们探究了这三个红树林生态系统沉积物中黑碳的含量、来源和组成。结果表明，黑碳含量在香港最高，其次是孟加拉国和广西（分别为0.18±0.02%、0.11±0.01%和0.05±0.01%），而黑碳/总有机碳（TOC）比值在孟加拉国最高，其次是广西和香港（分别为0.18±0.01、0.14±0.02和0.08±0.01）。化石燃料燃烧对红树林沉积物的贡献顺序为香港（59.0±0.3%）、孟加拉国（55.1±1.3%）、广西（50.0±3.4%）递减。这些空间变异性与周边地区的发展水平和能源结构有关。在香港红树林沉积物中，黑碳可能受远距离传输影响更大，且在埋藏前经历了更显著的光降解，导致其芳香性最低，这由（B5CA + B6CA）/BPCAs比值表明。我们证明了黑碳是红树林沉积物碳库中一个重要但不均一的组分。
