[Effects of drying and wetting cycles induced by tides on net ecosystem exchange of CO2 over a salt marsh in the Yellow River Delta, China.]

• DOI: 10.13287/j.1001-9332.201801.035
• Publication Date: 2018-01-01
• Authors: Wen He; Guang Xuan Han; Yan Xu; Xi Tao Zhang; Andong Wang; Chun Guang; Bao Yu Sun; Xiao Shuai Zhang
• Keywords: Salt marsh

As a unique hydrological characteristic, the tidal action can strongly affect carbon balance in salt marsh despite their short duration. Using eddy covariance technique, we measured net ecosystem CO2 exchange (NEE) and its environmental factors change over Yellow River Delta. It aimed to investigate effect of process drying wetting cycles induced by tides on NEE. The results showed that promoted daytime uptake, but it didn't clearly nighttime release. Tidal inundation was major factor influencing diurnal NEE distinct U-shaped curve both drought wet stages, not with substantial variation amplitude during stage. enhanced absorption CO2. Under stage, mean maximum photosynthetic rate (Amax), apparent quantum yield (α) respiration (Reco) were higher than those In addition, suppressed release from increased temperature sensitivity.潮汐作用作为盐沼湿地独特的水文特征能在短时间内强烈影响盐沼湿地的碳平衡.利用涡度相关和微气象监测技术,对黄河三角洲盐沼湿地净生态系统CO2交换(NEE)和环境因子进行监测,并同步监测潮汐变化,探究潮汐过程及潮汐作用下干湿交替对NEE的影响.结果表明: 潮汐过程促进了白天生态系统CO2的吸收但未对夜晚CO2的释放产生显著影响,潮汐淹水成为影响白天NEE的主要因子.干旱阶段和湿润阶段NEE的日平均动态均呈“U”型曲线,但干旱阶段NEE的变幅较小.干湿交替增强了白天生态系统CO2的吸收,干旱阶段最大光合速率(Amax)、表观量子产量(α)和生态系统呼吸(Reco)的均值均高于湿润阶段.此外,干湿交替减少了盐沼湿地夜晚NEE释放的同时增强了其温度敏感性.