摘要
以长江口滨海湿地的九段沙湿地和西沙湿地为研究区域,探究了滨海湿地水体中溶解态CH4浓度和通量的变化过程及影响因子.采样期间,CH4溶存浓度有显著的季节变化:九段沙秋季的CH4平均溶存浓度最大,为(0.30±0.19)μmol·L^(-1);西沙夏季的CH4平均溶存浓度最大,为(1.16±1.52)μmol·L^(-1).西沙的CH4平均溶存浓度((0.56±0.91)μmol·L^(-1))高于九段沙((0.18±0.17)μmol·L^(-1)).通过主成分分析发现,CH4的时空变化主要与滨海湿地的季节更替及潮汐作用有关,低温、高盐度和富氧环境都将抑制CH4的合成.对于不同的季节和研究区域,溶解态CH4的通量变化也有显著差异.九段沙和西沙水环境向大气扩散的CH4通量分别在秋季((0.45±0.43)nmol·m^(-2)·s^(-1))和夏季((3.34±5.21)nmol·m^(-2)·s^(-1))最大.两者向长江口水平输送的CH4通量分别在秋季((2.32±9.32)nmol·m^(-2)·s^(-1))和夏季((1.66±5.06)nmol·m^(-2)·s^(-1))最大.利用水质参数与CH4溶存浓度拟合多元回归方程,获得高频率、连续观测的CH4溶存浓度.进一步计算得到九段沙和西沙的溶解态CH4年均横向输送通量,分别为1.46 mg·m^(-2)·d^(-1)和0.34 mg·m^(-2)·d^(-1),年均垂向扩散通量分别为1.85 mg·m^(-2)·d^(-1)和2.90 mg·m^(-2)·d^(-1).还揭示了滨海湿地中溶解态CH4是大气和沿岸水体中CH4的重要来源之一.
The process of change and factors influencing dissolved CH4 concentration and flux in the coastal wetlands of Jiuduansha(JDS)and Xisha(XS)in the Yangtze Estuary were explored.The concentration of dissolved CH4 varied significantly during the sampling period,with the highest in JDS wetland being(0.30±0.19)μmol·L^(-1) during autumn,while that in XS wetland being(1.16±1.52)μmol·L^(-1) during summer.The average dissolved CH4 concentration in XS wetland((0.56±0.91)μmol·L^(-1))was slightly higher than that in JDS wetland((0.18±0.17)μmol·L^(-1)).Principal component analysis revealed that the temporal and spatial variations in CH4 were mainly related to seasonal variation and tidal cycling in coastal wetlands.The CH4 emission under low-temperature,high-salinity,and oxygen-rich water environments was limited.The fluxes of dissolved CH4 also showed seasonal and regional variations.The water-to-air diffusion of CH4 was the largest in autumn in JDS wetlands((0.45±0.43)nmol·m^(-2)·s^(-1))and in summer in XS wetlands((3.34±5.21)nmol·m^(-2)·s^(-1)).The lateral fluxes of dissolved CH4 were maximum in autumn in JDS wetlands((2.32±9.32)nmol·m^(-2)·s^(-1))and in summer in XS wetlands((1.66±5.06)nmol·m^(-2)·s^(-1)).Use of water quality parameters and dissolved CH4 concentration to fit a multiple regression equation produced a high-frequency and continuous CH4 concentration.The annual average lateral transport flux(JDS wetland:1.46 mg·m^(-2)·d^(-1);XS wetland:0.34 mg·m^(-2)·d^(-1))and annual average vertical diffusion flux(JDS wetland:1.85 mg·m^(-2)·d^(-1);XS wetland:2.90 mg·m^(-2)·d^(-1))of dissolved CH4 was calculated.The results show that dissolved CH4 in coastal wetlands is an important sources of CH4 in the atmosphere and coastal waters.
作者
张颖
张晓慧
刘婷婷
杨芷璇
唐剑武
ZHANG Ying;ZHANG Xiaohui;LIU Tingting;YANG Zhixuan;TANG Jianwu(State Key Laboratory of Estuarine and Coastal Research,East China Normal University,Shanghai 200241,China;Institute of Eco-Chongming,Shanghai 202162,China;Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station,Ministry of Education&Shanghai Science and Technology Committee,Shanghai 200241,China)
出处
《华东师范大学学报（自然科学版）》
CAS
CSCD
北大核心
2023年第3期93-107,共15页
Journal of East China Normal University(Natural Science)
基金
自然资源部海洋生态监测与修复技术重点实验室开放基金(MEMRT202001)
龙港市河口红树林生态系统监测项目(LGCG2021350)
蓝色海湾项目工程监测与评估项目。
