title: Salinity and nutrient contents of tidal water affects soil respiration and carbon sequestration of high and low tidal flats of Jiuduansha wetlands in different ways.
abstract: Soils were collected from low tidal flats and high tidal flats of Shang shoal located upstream and Xia shoal located downstream with different tidal water qualities, in the Jiuduansha wetland of the Yangtze River estuary. Soil respiration (SR) in situ and soil abiotic and microbial characteristics were studied to clarify the respective differences in the effects of tidal water salinity and nutrient levels on SR and soil carbon sequestration in low and high tidal flats. In low tidal flats, higher total nitrogen (TN) and lower salinity in the tidal water of Shang shoal resulted in higher TN and lower salinity in its soils compared with Xia shoal. These would benefit β-Proteobacteria and Anaerolineae in Shang shoal soil, which might have higher heterotrophic microbial activities and thus soil microbial respiration and SR. In low tidal flats, where soil moisture was high and the major carbon input was active organic carbon from tidal water, increasing TN was a more important factor than salinity and obviously enhanced soil microbial heterotrophic activities, soil microbial respiration and SR. While, in high tidal flats, higher salinity in Xia shoal due to higher salinity in tidal water compared with Shang shoal benefited γ-Proteobacteria which might enhance autotrophic microbial activity, and was detrimental to β-Proteobacteria in Xia shoal soil. These might have led to lower soil microbial respiration and thus SR in Xia shoal compared with Shang shoal. In high tidal flats, where soil moisture was relatively lower and the major carbon input was plant biomass that was difficult to degrade, soil salinity was the major factor restraining microbial activities, soil microbial respiration and SR.
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. Electronic address: celwang@tongji.edu.cn.
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; Collaborative Innovation Center for Regional Environmental Quality, China.
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Fu
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: Jianfang
authors.initials: J
authors.lastname: Yan
authors.affiliation: Ministry of Education, Key Laboratory for Biodiversity Science and Ecological Engineering, School of Life Science, Fudan University, Shanghai 200433, China.
authors.forename: Jihua
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Science and Environmental Studies, Hong Kong Institute of Education, Hong Kong, China.
authors.forename: Yiufai
authors.initials: Y
authors.lastname: 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: Yiquan
authors.initials: Y
authors.lastname: Le
authors.affiliation: Shanghai Jiuduansha Wetland Nature Reserve Administration, Shanghai 200135, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
mesh_terms: D002681:China; D004784:Environmental Monitoring; D054712:Salinity; D012623:Seawater / Q000737:chemistry*; D012988:Soil Microbiology; D053833:Wetlands
keywords: Aggravation of organic pollution and Eutrophication; Sea-level rise; Soil carbon turnover; Soil heterotrophic and autotrophic microbial activities; Soil microbial community; Yangtze River estuary