title: Effects of the addition of nitrogen and sulfate on CH4and CO2emissions, soil, and pore water chemistry in a high marsh of the Min River estuary in southeastern China.
abstract: Exogenous nitrogen (N) and sulfate (SO42-), resulting from human activity, can strongly influence the emission of CH4and CO2from soil ecosystems. Studies have reported the effects of N and SO42-on CH4and CO2emissions from inland peatlands and paddies. However, very few studies have presented year-round data on the effects of the addition of N and SO42-on CH4and CO2emissions in estuarine marshes. The effects of the addition of N and SO42-on the emission of CH4and CO2were investigated in a Cyperus malaccensis marsh in the high tidal flat of the Min River estuary of southeastern China from September 2014 to August 2015. Dissolved NH4Cl, KNO3, and K2SO4were applied every month, in doses of 24gN/SO42-m-2·yr-1. The emission of CH4and CO2showed distinct monthly and seasonal variations. Compared with the control, the addition of NH4Cl and NH4NO3+K2SO4showed increases in CH4fluxes (p<0.05), while the effects of the addition of KNO3and K2SO4on CH4were minor (p>0.05). NH4Cl had a positive impact on CO2emissions (p<0.01), while the addition of KNO3, K2SO4, and NH4NO3+K2SO4had minor positive impacts, compared to the control (p>0.05). Correlation analysis found that soil sulfate concentration, nitrogen availability and enzyme activity were the dominant factors influencing CH4and CO2variation. Our findings suggest that CH4and CO2emissions were influenced more by ammonium than by nitrate. We propose that the suppressive effect of additional sulfate on CH4production is insignificant, due to which the inhibition may be overestimated in the estuarine brackish marsh.
authors.affiliation: School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China; Key Laboratory of Humid Sub-tropical Eco-geographical Process of Ministry of Education, Fujian Normal University, Fuzhou 350007, China; Research Centre of Wetlands in Subtropical Region, Fujian Normal University, Fuzhou 350007, China.
authors.forename: Minjie
authors.initials: M
authors.lastname: Hu
authors.affiliation: Department of Biological Sciences, Florida International University, Miami, FL 33199, USA.
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Wilson
authors.affiliation: School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China; Key Laboratory of Humid Sub-tropical Eco-geographical Process of Ministry of Education, Fujian Normal University, Fuzhou 350007, China; Research Centre of Wetlands in Subtropical Region, Fujian Normal University, Fuzhou 350007, China.
authors.forename: Zhigao
authors.initials: Z
authors.lastname: Sun
authors.affiliation: School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China; Key Laboratory of Humid Sub-tropical Eco-geographical Process of Ministry of Education, Fujian Normal University, Fuzhou 350007, China; Research Centre of Wetlands in Subtropical Region, Fujian Normal University, Fuzhou 350007, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Ren
authors.affiliation: School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China; Key Laboratory of Humid Sub-tropical Eco-geographical Process of Ministry of Education, Fujian Normal University, Fuzhou 350007, China; Research Centre of Wetlands in Subtropical Region, Fujian Normal University, Fuzhou 350007, China. Electronic address: tongch@fjnu.edu.cn.
authors.forename: Chuan
authors.initials: C
authors.lastname: Tong
keywords: CH(4) and CO(2); High tidal flat; Min River estuary; Nitrogen and sulfate addition; Tidal marshes