辽河三角洲滨海湿地生态系统CO2释放机制

二氧化碳(CO2)是滨海湿地生态系统主要释放的温室气体,对其释放机制的研究是碳循环研究的重要内容。利用LI-8100A土壤呼吸速率检测系统,应用封闭系统的动态气室法,通过2012年5月对辽河三角洲光滩、翅碱蓬(Suaeda salsa)和芦苇(Phragmites australis)2种典型植被湿地类型的系统呼吸通量及其不同实验处理后的呼吸通量研究,探讨在这一季节条件下湿地生态系统的CO2释放途径与机制。研究表明,芦苇湿地呼吸通量高于翅碱蓬湿地,且站立植物的呼吸量的贡献在翅碱蓬湿地仅占24%,在芦苇湿地占40%。特别地,当湿地植物被移除后,湿地系统所产生的CO2通量会显著增高,由此揭示了滨海湿地植物一旦被破坏,其生态系统在短时间内会向大气释放大量的CO2。

EMISSION OF CARBON DIOXIDE IN THE COASTAL WETLANDS OF THE LIAOHE DELTA,CHINA

Carbon dioxide is likely the major greenhouse gas in the coastal wetland as the availability of sulfate inhibits CH4 release.Therefore,the study of the CO2 emission mechanism in the eco-system of the coastal wetland is of significance to carbon cycle and its budget.For this purpose,the LI-8100 A soil respiration system was adopted to measure the soil CO2 flux in the Liaohe Delta during May,2012,and the method of enclosure chamber measurement was used to explore wetland CO2 emission mechanism for three types of coastal wetlands：unvegetated wetlands,Suaeda salsa and Phragmites australis wetlands.It discovered that during this season of a year the Phragmites wetland has a higher respiration rate（3 041.59±320.66mg·m-2·h-1）than the Suaeda wetland（534.09±56.06mg·m-2·h-1）,and both are higher than relevant records of CO2 flux from literatures.Aboveground biomass has a positive liner correlation with the plant respiration rate.In the wetland ecosystem,CO2 released from the soil accounts for~60% of total CO2 emission.It is also observed that the CO2 emission will be significantly increased after wetland vegetation being destroyed,that means that the harvest of wetland plants is the cause of significant release of greenhouse gas CO2.