浙南人工红树林土壤呼吸季节变化特征及其对蓝碳功能的影响

Seasonal variations of soil respiration and its effect on blue carbon sink function in the restored mangrove wetland in southern Zhejiang province

土壤呼吸(soil respiration,R_(soil))是生态系统向大气释放二氧化碳(arbon dioxide,CO_(2))的主要碳源,其微小变化对红树林湿地碳汇有重要影响。本文以2021年原位实时监测的每月浙南人工红树林湿地R_(soil)及其环境因子数据为基础,探究了R_(soil)的季节变化特征及其对生态系统呼吸(ecosystem respiration,R_(eco))的贡献,并分析了R_(soil)对浙南人工红树林生态系统固碳能力的影响。结果表明:(1)浙南人工红树林湿地R_(soil)具有明显的季节变化,在夏季达到峰值;R_(soil)关键环境驱动因子为土壤温度(soil temperature,T_(S))和土壤湿度(soil humidity,W_(S)),二者的综合作用可以解释84.6%的R_(soil)变化;(2)尽管R_(soil)是浙南红树林R_(eco)的主要贡献者,但年平均R_(soil)[(0.69±0.54)μmol/(m^(2)·s)]低于其他滨海湿地;(3)R_(soil)随林龄增大而上升,然而其增长幅度远小于净生态系统CO_(2)交换量(net ecosystem CO_(2)exchange,NEE)的增长幅度,表明浙南引种人工红树林有利于滨海湿地固碳增汇。研究结果有利于深入认识浙南人工红树林R_(soil)变化特征及规律,进而为准确评估浙南红树林碳收支及其碳中和潜力提供数据支撑和理论依据。

Soil respiration(R_(soil))is the largest source of carbon dioxide(CO_(2))released from ecosystems to the atmosphere,and small changes in Rsoil have a great impact on mangrove wetland carbon sequestration.Based on the data of R_(soil) and correlative environmental factors monitored monthly in the restored mangrove wetland in south Zhejiang throughout 2021,we explored the seasonal variations of R_(soil) and its contribution to ecosystem respiration(R_(eco)),and the influence of R_(soil) on carbon sequestration ability.The results showed that the R_(soil) of the mangrove wetland had obvious seasonal variations and reached the peak in summer.The key environmental drivers of R_(soil) were soil temperature(T_(S))and soil humidity(W_(S)),the combined effects of T_(S) and W_(S) could explain 84.6%changes in R_(soil).Though Rsoil was the main contributor to R_(eco) in the restored mangroves wetland,the annual average value of R_(soil)[(0.69±0.54)µmol/(m^(2)·s)]was lower than that of other coastal wetlands.R_(soil) increased gradually with stand age,but the increasing degree of R_(soil) was considerably lower than that of net ecosystem CO_(2) exchange(NEE),indicating that the restored mangrove was conducive to the coastal blue carbon.The results will be beneficial to deepen the understanding of the change characteristics of R_(soil) and carbon budget in order to accurately evaluate carbon neutralization potential of mangroves wetlands in southern Zhejiang province.