Contributions of plant‐ and microbial‐derived residuals to mangrove soil carbon stocks: Implications for blue carbon sequestration

• Published in: Functional ecology Vol. 38; no. 3; pp. 573 - 585
• Main Authors: Qin, Guoming, He, Weijun, Sanders, Christian J., Zhang, Jingfan, Zhou, Jinge, Wu, Jingtao, Lu, Zhe, Yu, Mengxiao, Li, Yingwen, Li, Yongxing, Lambers, Hans, Li, Zhian, Wang, Faming
• Format: Journal Article
• Language: English
• Published: London Wiley Subscription Services, Inc 01.03.2024
• Subjects: Aerobic conditions; amino sugars; Anaerobic conditions; Biomass; blue carbon; Carbon sequestration; carbon sinks; Carbon sources; chronosequences; Climate change; Climate change mitigation; ecology; Ecosystems; Environmental changes; fungi; Lignin; lignin phenols; mangrove restoration; mangrove soils; Mangroves; microbial necromass; Microorganisms; Mineralization; necromass; Organic carbon; phenol; Phenols; Restoration; salinity; Sediments; soil carbon; Soil microorganisms; soil organic carbon; Soil profiles; Soil properties; Soils; Sugar; sugars; Tidal flats; total nitrogen; trees
• DOI: 10.1111/1365-2435.14497
• ISSN: 0269-8463

Coastal blue carbon ecosystems, particularly mangroves, are becoming increasingly recognised for their importance in mitigating climate change. Still, the specific patterns and drivers of plant lignin components and microbial necromass accumulation in these ecosystems are unclear. In response, we carried out a study along a 40‐year mangrove restoration chronosequence, measuring lignin phenol and amino sugar concentrations in soil profiles (0–100 cm) as indicators of plant‐based and microbial‐derived residues, respectively. Our results showed that restoration significantly increased plant lignin phenol and amino sugar concentrations, with mature mangroves having much higher concentrations than tidal flats. During restoration, the fungal necromass was greater than the bacterial necromass. The factors influencing the lignin phenols were tree biomass, total nitrogen, pH and salinity, while those influencing the formation of amino sugars were total biomass, soil C: N ratio and pH. While the amino sugars decreased, the lignin phenols increased with the content of SOC, providing evidence of the important role lignin phenol components play in the formation of SOC in mangrove. Synthesis: By separating soil carbon into plant‐based and microbial‐derived components, our results demonstrate that the carbon stock in mangrove sediments is vulnerable to disturbances and that changes from anaerobic to aerobic conditions cause significant carbon mineralisation. The precise identification of soil carbon sources in blue carbon ecosystems could aid in elucidating the mechanisms of soil carbon sequestration and their responses to environmental changes. Read the free Plain Language Summary for this article on the Journal blog. 摘要 滨海湿地生态系统，尤其是红树林，在缓解全球气候变化过程中起重要作用。植物和微生物残体是土壤有机碳的两大主要来源，但它们在红树林生态系统恢复过程中的分布规律尚不明晰。 本研究以木质素酚和氨基糖分别指示植物和微生物来源的有机碳组分，对比分析了两者在红树林恢复过程中对土壤有机碳的贡献及其影响因子。 结果显示，红树林的恢复显著提高了土壤中木质素酚和氨基糖的含量，真菌残体的累积量要显著高于细菌。木质素酚的形成主要受树木生物量、土壤总氮、pH和盐度的影响，而土壤微生物生物量、土壤碳氮比和pH值是影响氨基糖形成的主要因子。总体而言，随着红树林的恢复，植物来源组分在有机碳中的占比呈增加趋势，而微生物来源组分则呈相反趋势。 本研究通过将土壤有机碳来源分为植物和微生物来源，发现红树林土壤中的有机碳稳定性不高，当土壤从厌氧到好氧的条件转换会导致固存在红树林土壤中的有机碳流失。因此，准确识别蓝碳生态系统中的土壤碳源有助于阐明土壤碳固定机制及其对环境变化的响应。 Read the free Plain Language Summary for this article on the Journal blog.