Zhang Xinyu, Song Zhaoliang, Wu Yuntao, Wu Lele, Li Qiang, Hao Qian, Xia Shaopan, Wang Yidong, Ran Xiangbin, Fang Yunying, Wang Hailong
Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China; Haihe Laboratory of Sustainable Chemical Transformations, Tianjin, China.
Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China; Haihe Laboratory of Sustainable Chemical Transformations, Tianjin, China.
J Environ Manage. 2025 Sep;392:126891. doi: 10.1016/j.jenvman.2025.126891. Epub 2025 Aug 7.
Carbon (C), nitrogen (N), and phosphorus (P) are essential elements for plants, while silicon (Si) is a beneficial element. Plants play a crucial role in sustainable C sequestration in coastal salt marshes. This study investigated the patterns, driving factors, and effects on ecosystem productivity of C, N, P, and Si contents and ratios in stems, leaves, and sheaths of coastal salt marsh plants of China, including Phragmites australis, Spartina alterniflora, and Suaeda glauca. Our results showed that P. australis had the highest C (459 ± 1.56 g kg), Si (14.1 ± 0.62 g kg), and Si/P (19.9 ± 1.63), S. glauca had the highest N (11.8 ± 1.68 g kg), P (1.28 ± 0.23 g kg), C/Si (266 ± 46.7), and N/Si (7.10 ± 1.20). The growth of salt marsh plants in coastal wetlands in China was affected by N limitation (N/P = 11.4), with S. alterniflora demonstrating the most severe N deficiency (N/P = 7.92 ± 0.40). Plant elements contents were mainly influenced by species and tissues. The climate factors in this study include mean annual temperature (MAT), mean annual precipitation (MAP), and Palmer Drought Severity Index (PDSI). Soil factors include pH, electrical conductivity (EC), soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), and available silicon (ASi). Multivariate regression analysis revealed that soil salinity was the main factor affecting the overall stoichiometry of salt marsh plants by altering the vegetation types from Broad-salt type (P. australis) to Salt-tolerant halophytes (S. glauca and S. alterniflora). The stoichiometry of P. australis was mainly affected by climate factors, S. alterniflora and S. glauca were greatly affected by soil factors. Random forest results showed that C/Si, Si/P, N/P, and N/Si ratios were the main influencing factors of net primary productivity (NPP). Environmental factors altered NPP by regulating ratios (e.g., PDSI increased in Si/P of P. australis, SOC and TN decreased N/P of S. glauca). In addition, the Si cycle affected the NPP of coastal salt marsh plants by influencing the C/Si, Si/P and N/Si. The effects of Si cycling and its stoichiometric ratios on productivity and C sequestration in coastal salt marshes should be given importance when implementing C management in coastal wetlands.
碳（C）、氮（N）和磷（P）是植物必需的元素，而硅（Si）是有益元素。植物在沿海盐沼的可持续碳固存中起着关键作用。本研究调查了中国沿海盐沼植物芦苇、互花米草和碱蓬的茎、叶和叶鞘中C、N、P和Si含量及比率的模式、驱动因素及其对生态系统生产力的影响。我们的结果表明，芦苇的C含量最高（459±1.56 g/kg）、Si含量最高（14.1±0.62 g/kg）、Si/P最高（19.9±1.63）；碱蓬的N含量最高（11.8±1.68 g/kg）、P含量最高（1.28±0.23 g/kg）、C/Si最高（266±46.7）、N/Si最高（7.10±1.20）。中国沿海湿地盐沼植物的生长受氮限制（N/P = 11.4）影响，互花米草表现出最严重的氮缺乏（N/P = 7.92±0.40）。植物元素含量主要受物种和组织的影响。本研究中的气候因子包括年均温度（MAT）、年平均降水量（MAP）和帕尔默干旱严重度指数（PDSI）。土壤因子包括pH值、电导率（EC）、土壤有机碳（SOC）、总氮（TN）、总磷（TP）和有效硅（ASi）。多元回归分析表明，土壤盐度是影响盐沼植物整体化学计量的主要因素，它使植被类型从广盐型（芦苇）转变为耐盐盐生植物（碱蓬和互花米草）。芦苇的化学计量主要受气候因子影响，互花米草和碱蓬则受土壤因子影响较大。随机森林结果表明，C/Si、Si/P、N/P和N/Si比率是净初级生产力（NPP）的主要影响因素。环境因子通过调节比率改变NPP（例如，PDSI增加芦苇的Si/P，SOC和TN降低碱蓬的N/P）。此外，硅循环通过影响C/Si、Si/P和N/Si影响沿海盐沼植物的NPP。在沿海湿地实施碳管理时，应重视硅循环及其化学计量比率对沿海盐沼生产力和碳固存的影响。
