潮汐作用下短叶茳芏湿地N2O排放规律及踩踏干扰研究

采用静态箱-气相色谱及浮箱-气相色谱法,对闽江河口鳝鱼滩湿地潮间带短叶茳芏（Cyperus malaccensis var.brevifolius）湿地和踩踏造成的裸露湿地N2O通量进行测定。结果表明,短叶茳芏湿地在涨潮前、涨落潮中和落潮后N2O通量差异性极显著（P=0.001〈0.01）,不同潮日（7 d内）的N2O通量差异性不显著（P=0.103〉0.05）。涨潮前、涨落潮过程中和落潮后,短叶茳芏湿地平均通量分别为19.48μg.m-2.h-1、12.80μg.m-2.h-1和51.41μg.m-2.h-1,总平均通量为33.1μg.m-2.h-1,表明白天短叶茳芏湿地为N2O的排放源。涨潮前,末次观测短叶茳芏湿地N2O通量最低,多数都为负值,落潮后过2~3 h,短叶茳芏湿地N2O通量出现日最大值。踩踏改变了短叶茳芏湿地N2O通量规律并降低了短叶茳芏湿地N2O通量。涨潮前,裸露湿地N2O平均排放量（27.25μg.m-2.h-1）低于短叶茳芏湿地（42.51μg.m-2.h-1）,但差异性不显著（P=0.527〉0.05）;落潮后,裸露湿地N2O平均排放量（0.86μg.m-2.h-1）极显著低于短叶茳芏湿地（63.59μg.m-2.h-1）（P=0.006〈0.01）。

Tidal action and tread affecting nitrous oxide fluxes in intertidal Cyperus malaccensis var.brevifolius marsh

The enclosed dark chamber technique was used and the measurements on nitrous oxide fluxes from Cyperus malaccensis var.brevifolius were taken during three periods（before the flood,in the course of rising and ebbing tide,and after the ebb） and bare wetland was tread by people who catch crabs and cattle（before the flood,and after the ebb） in the Shanyutan wetland which is the largest wetland in the Min River estuary region.The results showed that nitrous oxide fluxes from C.malaccensis wetland affected tidal action have very significant difference（P=0.0010.01） before the flood,in the course of rising and ebbing tide,and after the ebb,but not significant difference（P=0.1030.05） in different day.The average nitrous oxide fluxes from C.malaccensis wetland before the flood,in the course of rising and ebbing tide were 19.48 μg.m-2.h-1、12.80 μg.m-2.h-1and 51.41 μg.m-2.h-1,respectively.The average nitrous oxide fluxes in a tidal cycle was 33.1 μg.m-2.h-1.It showed C.malaccensis wetland in the day was a source of nitrous oxide.The nitrous oxide fluxes from C.malaccensis wetland at the end time observation before the flood was lowest than other time,most were negative,the maximum of the nitrous oxide fluxes spring up 2~3 hours after the ebbing tide.The law of nitrous oxide flux was changed by tread of people who catch crabs and cattle.At the same time,tread also decreased the fluxes of nitrous oxide emission.Emission of bare wetland（27.25 μg.m-2.h-1） was lower than C.malaccensis wetland（42.51 μg.m-2.h-1） before the flood,but differentiation is not significant（P=0.5270.05）;Emission of bare wetland（0.86 μg.m-2.h-1） was lower than C.malaccensis wetland（63.59 μg.m-2.h-1） after the ebb,but difference is highly significant（P=0.0060.01）.