title: Salinity influence on soil microbial respiration rate of wetland in the Yangtze River estuary through changing microbial community.
abstract: Estuarine wetland, where freshwater mixes with salt water, comprises different regions (rivers and marine ecosystems) with significantly varying tidal salinities. Two sampling areas, ZXS and JS, were selected to investigate the effect of tidal salinity on soil respiration (SR). ZXS and JS were located in Zhongxia Shoal and Jiangyanan Shoal of Jiuduansha Wetland respectively, with similar elevation and plant species, but significantly different in salinity. The results showed that with almost identical plant biomass, the SR and soil microbial respiration (SMR) of the tidal wetland with lower salinity (JS) were significantly higher than those of the tidal wetland with higher salinity (ZXS) (p<0.05). However, unlike SMR and SR, the difference in the soil microbial biomass (SMB) was not significant (p>0.05) with the SMB of ZXS a little higher than that of JS. The higher SMR and SR of JS may be closely connected to the soil microbial community structures and amount of dominant bacteria. Abundant β- and γ-Proteobacteria and Actinobacteria in JS soil, which have strong heterotrophic metabolic capabilities, could be the main reason for higher SMR and SR, whereas a high number of ε-Proteobacteria in ZXS, some of which have carbon fixation ability, could be responsible for relatively lower carbon output. Path analysis indicated that soil salinity had the maximum negative total influencing coefficient with SMR among the various soil physical and chemical factors, suggesting that higher soil salinity, restricting highly heterotrophic bacteria, is the principle reason for lower SMR and SR in the ZXS.
authors.affiliation: Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Collaborative Innovation Center for Regional Environmental Quality, China. Electronic address: xxfei1987@yeah.net.
authors.forename: Xue
authors.initials: X
authors.lastname: Fei Xi
authors.affiliation: Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Collaborative Innovation Center for Regional Environmental Quality, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; College of Civil Engineering, Tongji University, Shanghai 200092, China. Electronic address: celwang@tongji.edu.cn.
authors.forename: Jia
authors.initials: J
authors.lastname: Jun Hu
authors.affiliation: Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Collaborative Innovation Center for Regional Environmental Quality, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Shu Tang
authors.affiliation: Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Collaborative Innovation Center for Regional Environmental Quality, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Collaborative Innovation Center for Regional Environmental Quality, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Hua Fu
authors.affiliation: Shanghai Jiuduansha Wetland Nature Reserve Administration, Shanghai 200135, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Science and Environmental Studies, Hong Kong Institute of Education, Hong Kong, China.
authors.forename: Yiu
authors.initials: Y
authors.lastname: Fai Tsang
authors.affiliation: Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Collaborative Innovation Center for Regional Environmental Quality, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Nan Zhang
authors.affiliation: Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Collaborative Innovation Center for Regional Environmental Quality, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Hai Chen
mesh_terms: D002681:China; D063366:Estuaries; D059013:Microbial Consortia; D045483:Rivers; D054712:Salinity; D053833:Wetlands
keywords: Biomass; Estuarine tides; Jiuduansha; Microbial community; Respiration; Salts