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Chinese Journal of Applied Ecology ›› 2018, Vol. 29 ›› Issue (1): 269-277.doi: 10.13287/j.1001-9332.201801.035

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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.

HE Wen-jun1,2, HAN Guang-xuan1*, XU Yan-ning1, ZHANG Xi-tao3, WANG An-dong3, CHE Chun-guang3, SUN Bao-yu4, ZHANG Xiao-shuai3   

  1. 1Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China;
    2University of Chinese Academy of Sciences, Beijing 100049, China;
    3Administration Bureau of the Yellow River Delta National Nature Zone Reserve, Dongying 257091, Shandong, China;
    4School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
  • Received:2017-07-25 Online:2018-01-18 Published:2018-01-18
  • Contact: * E-mail: gxhan@yic.ac.cn
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (41671089) and the Science and the Technology Service Network Initiative of the Chinese Academy of Sciences (KFJ-EW-STS-127).

Abstract: As a unique hydrological characteristic, the tidal action can strongly affect carbon balance in a salt marsh despite their short duration. Using the eddy covariance technique, we measured the net ecosystem CO2 exchange (NEE) and its environmental factors and tidal change over a salt marsh in the Yellow River Delta. It aimed to investigate the effect of tidal process and drying and wetting cycles induced by tides on NEE. The results showed that the tidal process promoted the daytime CO2 uptake, but it didn’t clearly affect the nighttime CO2 release. Tidal inundation was a major factor influencing daytime NEE. The diurnal change of NEE showed a distinct U-shaped curve on both drought and wet stages, but not with substantial variation in its amplitude during the drought stage. The drying and wetting cycles enhanced the absorption of daytime CO2. Under drought stage, the mean of the maximum photosynthetic rate (Amax), apparent quantum yield (α) and ecosystem respiration (Reco) were higher than those in wet stage. In addition, the drying and wetting cycles suppressed the nighttime CO2 release from the salt marsh but increased its temperature sensitivity.

Key words: tidal action, drying and wetting cycle, net ecosystem CO2 exchange, salt marsh