title: Responses of ecosystem carbon dioxide exchange to nitrogen addition in a freshwater marshland in Sanjiang Plain, Northeast China.
abstract: It has widely been documented that nitrogen (N) stimulates plant growth and net primary production. But how N affects net ecosystem CO2 exchange (NEE) is still dispute. We conduct an experimental study to assess the response of NEE to N addition in a freshwater marsh. Experimental treatments involved elevated N and control treatments on triplicate 1 m(2) plots. Gas exchange, air temperature, plant biomass and leaf area as well as N% of leaf were measured from 2004 to 2005. The results indicated that N addition initially decreased the CO2 sequestration but the trend changed in the second year. It was concluded that N addition enhanced the greenhouse effect in marshland as far as global warming potential (GWP) is concerned. This increase was attributed to a substantial increase in CH4 and N2O emissions after N addition. We recommended long-term studies to further clarify the effect of N addition on NEE.
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Lihua
authors.initials: L
authors.lastname: Zhang
authors.forename: Changchun
authors.initials: C
authors.lastname: Song
authors.forename: Philip N
authors.initials: PN
authors.lastname: Nkrumah
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D057486:Carbon Cycle; D002245:Carbon Dioxide / Q000032:analysis*; D002681:China; D005618:Fresh Water / Q000737:chemistry*; D017752:Greenhouse Effect; D008697:Methane / Q000032:analysis; D009584:Nitrogen / Q000032:analysis*; D009585:Nitrogen Dioxide / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*; D053833:Wetlands
chemical_list: D000393:Air Pollutants; D014874:Water Pollutants, Chemical; D002245:Carbon Dioxide; D009584:Nitrogen; D008697:Methane; D009585:Nitrogen Dioxide
keywords: Freshwater marshland; Global warming potential; Net ecosystem carbon exchange; Nitrogen addition