Spatiotemporal variations of nitrous oxide distribution and flux in estuaries of Guangdong Province

The concentrations and water-atmosphere fluxes of dissolved N2O were investigated in estuaries of 13 rivers of Guangdong Province during July(flooded season) and December(dry season),2011.N2O concentrations in the surface water were measured by purge and trap-gas chromatography,N2O water-atmosphere fluxes were estimated by Liss Merlivat formula.The results demonstrated that dissolved N2O concentrations in the flooded season were 15.37-175.22 nmol/L,with an average of(73.77±43.58) nmol/L,N2O water-atmosphere fluxes in flooded season were 0.26-5.40 μmol/(m2.d),with an average of(2.53±1.94) μmol/(m2.d).While in dry season,N2O concentrations ranged from 44.26 nmol/L to 366.11 nmol/L,with an average of(126.61±102.74) nmol/L,N2O water-atmosphere fluxes ranged from 0.86 μmol/(m2.d) to 21.88 μmol/(m2.d),with an average of(7.50±6.65) μmol/(m2.d).N2O concentrations and water-atmosphere fluxes of flooded season were lower than those of dry season.Compared with other studies,the estuaries in this study had lower N2O concentrations and water-atmosphere fluxes.