芦苇在微咸水河口湿地甲烷排放中的作用  

Effects of Phragmites australis on methane emission from a brackish estuarine wetland

作　　者：马安娜[1] 陆健健[1] 

机构地区：[1]华东师范大学河口海岸国家重点实验室,上海200062

出　　处：《生态学报》2011年第8期2245-2252,共8页Acta Ecologica Sinica

基　　金：高等学校学科创新引智计划(B08022);上海市科学技术委员会项目(07DZ12039);华东师范大学优秀博士研究生培养基金(2009012)

摘　　要：以长江口微咸水河口湿地为研究对象,通过模拟潮汐淹没和改进的静态箱法,针对芦苇在不同淹水条件下对甲烷的传输作用进行了研究。结果表明,长期淹没样点割除芦苇前后平均甲烷释放分别为1.60 mgCH4 m-2h-1和0.50 mgCH4 m-2h-1,而短期淹没样点割除芦苇前后平均甲烷释放分别为0.94 mgCH4 m-2h-1和0.55 mgCH4 m-2h-1。芦苇的存在增加了大约41.5%—69%的甲烷释放,割除芦苇导致长期淹没样点甲烷释放显著地减少。从淹水前到淹水后的一个潮周期内,长期淹没样点和短期淹没样点的甲烷释放分别在淹没期达到最小和最大释放(1.21 mgCH4 m-2h-1和1.18 mgCH4 m-2h-1),说明芦苇对甲烷的传输作用受到潮汐淹没程度的影响。实验室针对芦苇自身产甲烷的可能性进行的离体芦苇茎干和叶片的甲烷释放研究发现,离体茎干释放大约0.7μL/L和0.2μL/L甲烷,且下部茎干的甲烷释放量要明显高于上部茎干和叶片,随后均不再增加。结果进一步证实芦苇增加的甲烷排放来自对土壤气体的传输。同时,传输作用主要发生在植株的下部茎干。A self-deigned pond with different height steps was used to simulate the real flood current and ebb current by controlling water influx and efflux,and improved static closed chambers were placed on two steps of different heights to study methane facilitated by P.australis from different submergence condition,long-term submergence and short-term submergence,respectively.The results showed that mean methane emissions from the site of long-term submergence with and without P.australis were 1.60 mgCH4 m-2h-1 and 0.50 mgCH4 m-2h-1,respectively,while mean methane emissions from the site of short-term submergence with and without P.australis were 0.94 mgCH4 m-2h-1 and 0.55 mgCH4 m-2h-1,respectively.These sites at which P.australis were clipped had lower emission rates indicating an overall stimulating effect of plants on methane emission.The P.australis contributed 41.5%-69% of the total methane emission.In the site of long-term submergence,methane emission reduced obviously when the P.australis was clipped.During a cycle of flood current and ebb current,from pre-submergence,during the period of submergence to post-submergence,methane emissions from the site of long-term submergence and the site of short-term submergence reached the minimum（1.21 mgCH4 m-2h-1） and maximum（1.18 mgCH4 m-2h-1） when sites were submerged,and methane emission during the period of submergence differed significantly from pre-submergence and post-submergence,indicating that the transport effect of P.australis was affected directly by tidal submergence. Incubation experiment was further conducted to study other possible reasons of different methane emissions besides transport effect.The study mainly focused on aerobic methane emission from aboveground tissues of P.australis.The stems and leaves were cut into small sections and sealed for measuring methane emission from these detached tissues.The results showed that methane emissions from detached stems were 0.2-0.7μL/L.Physically cutting the stems hastened elimination of methane from the

关 键 词：长江口 传输作用 淹没周期 芦苇 

分 类 号：X173[环境科学与工程—环境科学]