Ouyang Xiaoguang, Guo Fen, Lee Shing Yip
Research Centre of Ecology & Environment for Coastal Area and Deep Sea, Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China; Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, China; Simon F. S. Li Marine Science Laboratory, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong.
Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, China; Simon F. S. Li Marine Science Laboratory, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong.
Sci Total Environ. 2024 Jan 1;906:167511. doi: 10.1016/j.scitotenv.2023.167511. Epub 2023 Oct 2.
Mangroves are highly efficient in sequestering carbon from the atmosphere and can accumulate carbon in sediments for millennials. However, The fate of mangrove carbon has not been well constrained due to the lack of data on different pools of sediment carbon sinks and sources. This study examined the variation of carbon stocks and fluxes at the water-sediment-air interface in both estuarine mangroves (natural: Mai Po, restored: Gei Wai) and oceanic mangroves (Ting Kok). There are divergent patterns in biogeochemical variables at the sediment-water-air interface, likely due to significant variation within sites. Total sediment carbon stocks (TCs) ranked in the order of restored estuarine mangroves (392.5 ± 8.8 Mg ha), natural estuarine mangroves affected by aquaculture (315.2 ± 21.4 Mg ha) and oceanic mangroves (229.1 ± 32.3 Mg ha). Sediment organic carbon stocks (SOC) and inorganic carbon stocks (SIC) accounted for 84.1-90.2 % and 9.8-15.9 % of TC, respectively. The highest sediment-air CO and CH fluxes occurred in restored and natural estuarine mangroves affected by aquaculture, respectively. The isotope of CO fluxes (δC-CO) indicates higher contributions from the degradation of mangrove-derived organic carbon in restored (-25.94 ‰ ± 3.37 ‰) and natural estuarine mangroves affected by aquaculture (-25.54 ‰ ± 0.96 ‰) than in oceanic mangroves (-21.55 ‰ ± 1.36 ‰). The isotope of CH fluxes (δC-CH) indicates CH production dominated by acetate fermentation in restored estuarine mangroves but dominated by the reduction of CO for other sites. Future studies should better constrain the fate of mangrove carbon by considering local drivers.
红树林在从大气中固碳方面效率极高，并且能够在沉积物中积累碳长达数千年。然而，由于缺乏关于沉积物碳汇和碳源不同库的数据，红树林碳的命运尚未得到很好的界定。本研究考察了河口红树林（天然：米埔，恢复：基围）和海洋红树林（汀角）在水 - 沉积物 - 空气界面处碳储量和通量的变化。沉积物 - 水 - 空气界面处的生物地球化学变量存在不同模式，这可能是由于各地点内部存在显著差异。总沉积物碳储量（TCs）的排序为：恢复的河口红树林（392.5 ± 8.8 Mg/公顷）、受水产养殖影响的天然河口红树林（315.2 ± 21.4 Mg/公顷）和海洋红树林（229.1 ± 32.3 Mg/公顷）。沉积物有机碳储量（SOC）和无机碳储量（SIC）分别占TC的84.1 - 90.2%和9.8 - 15.9%。沉积物 - 空气的CO和CH通量最高值分别出现在受水产养殖影响的恢复和天然河口红树林中。CO通量的同位素（δ¹³C - CO）表明，恢复的（-25.94‰ ± 3.37‰）和受水产养殖影响的天然河口红树林（-25.54‰ ± 0.9‰）中，红树林衍生有机碳降解的贡献高于海洋红树林（-21.55‰ ± 1.36‰）。CH通量的同位素（δ¹³C - CH）表明，恢复的河口红树林中CH产生以乙酸发酵为主，而其他地点则以CO还原为主。未来的研究应通过考虑当地驱动因素，更好地界定红树林碳的命运。
