The Research on the Characters Variation of the Fluxes of CH4 Were Affected by the Tide in Jiangsu Salt Marsh Wetlands

YAN Wen; WANG Jinxin; ZHAO Yunhao; GUO Nan

Abstract：Methane is one of the most important greenhouse gases in the atmosphere,it has an significant contribution to the global warming and also play an important role in global carbon cycle.We had used chambers over an annual cycle in July 2013(growing season) and in December 2013 (non-growing season) in Jiangsu salt marsh wetlands to measure the fluxes of CH4.The results showed that the fluxes of CH4 were 0.26±0.44mg · m-2 · d-1,25.83±4.25mg · m 2 · d-1 and 2.68±1.47mg · m-2 · d-1 in the bare flat,Spartina alterniflora,Aeluropus littoralis,which were was regarded as a source for CH4.The fluxes of CH4 were-0.56±0.94mg · m-2 · d-1in Suaeda salsa were considered as a sink of CH4.The fluxes of CH4were 16.90±3.71mg · m-2 · d-1 in the tidal creek higher than the fluxes of CH4are 5.17±2.llmg · m-2 · d-1and 8.93 3.21mg m-2 d-1in the recent tidal creek andfar away from the tidal creek.The fluxes of CH4 in growing season were 10.48 2.90mg m-2 d-1 higher than the fluxes of CH4were 9.65 2.29mg m-2 d-1 in non-growing season,but the fluxes were approximate in vegetation zone.The fluxes of CH4 in growing season tide cyclical variation at flood tide were higher than the fluxes of CH4at slack tide and ebb tide.Above ground plant biomass had different effects on the CH4 fluxes,the fluxes were increasing in Spartina alterniflora,the fluxes were decreasing in Suaeda salsa and Aeluropus littoralis.Salt marsh CH4 emissions were associated with abundant organic matter.The organic matter provided the CH4with the substrate.In the alkali salt marsh environment,the fluxes of CH4 were positively correlated to pH.The concentration of SO42 between 530mg/L and 1100mg/L were positively correlated to the fluxes of CH4,were negatively correlated to the fluxes of CH4.The light intensity and temperate were positively correlated to the fluxes of CH4 in growing season.