在全球气候变暖和盐水入侵的背景下,探究湿地枯落物分解和CO2释放对盐度和水淹的响应具有重要意义.以闽江河口湿地的短叶茳芏为研究对象,模拟不同盐度和水淹条件下枯落物分解.研究结果表明:(1)盐度升高抑制枯落物的分解(p〈0.01),低盐(5)、中盐(10)、高盐(15)在非水淹条件下分别比对照(0)的失重率平均减少10.83%、17.93%和29.39%,水淹条件下平均减少24.18%、31.62%和47.46%.(2)对照组的枯落物分解速率为水淹条件(0.0070 d^-1,t(0.95)=0.76 a)大于非水淹条件(0.0051 d^-1,t0.95=0.94 a),而处理组的枯落物分解速率和CO2释放速率均呈现出非水淹条件大于水淹条件.非水淹的枯落物CO2释放通量比水淹条件的增长7.05%-86.23%.(3)在枯落物分解95%的干物质的期间内,与水淹条件相比,非水淹对照组平均每g干物质释放的CO2高于水淹对照组34.49%;然而,随盐度升高,非水淹条件下的平均每g干物质释放的CO2受抑制.(4)盐度和水淹对枯落物残留量的贡献率分别为24.82%和14.29%,对枯落物CO2释放通量的贡献率分别为75.62%和6.13%.
Response of litter decomposition and carbon dioxide( CO2) releases to salinity and inundation has an important significance under the background of global climate warming and saltwater intrusion. This study used a microcosm experiment to determine the impact of different salinity and inundation on litter decomposition and CO2 releases of Cyperus malaccensis from the Min River estuary,SE China. The results show that,(1)the litter mass loss rates of in the high salinity( 15 pus),middle salinity( 10 psu) and low salinity( 5 psu) treatments decreased about 10.83%,17.93% and 29.39%compared with control treatment( 0 psu) under the flooded condition,and about 24. 18%,31. 62% and 47. 46% under the un-flooded condition,respectively;(2) the decomposition rates of C. Malaccensis in the flooded condition of the control treatment was 0. 0070 d^-1( t0.95= 0. 76 a),which was significantly higher than that in the un-flooded condition of 0.0051 d^-1( t0.95= 0.94 a)( p〈0.05). However,the decomposition rates of C. Malaccensis andits CO2 release rates were higher in un-flooded condition than in flooded condition for all treatments. Overall,the CO2 releases rate of C. Malaccensis litter in un-flooded condition increased by 7.05% - 86. 23% as compared with in flooded condition.(3) During the decomposition period of 95% dry matter,compared with flooded condition,CO2 releases in un-flooded were higher about 34.49% in control treatment,but inhibited by an increase of salinity.(4)Salinity and inundation contributed about 24.82% and 14.29% to litter mass loss,respectively,and about 75.62% and 6.13% to CO2 release rates.