沉水植物恢复对湖泊沉积物产甲烷菌的影响研究

IMPACTS OF SUBMERGED MACROPHYTES REHABILITATION ON THE METHANOGENIC COMMUNITY IN THE SEDIMENT OF FRESHWATER LAKES

为探明沉水植物恢复对湖泊沉积物中产甲烷菌的影响,本文选用杭州西湖沉水植物恢复区域进行研究,同时对比分析未进行沉水植物恢复区域。产甲烷菌多样性和群落结构分析采用限制性片段长度多态性分析(PCR-RFLP)及分子克隆等技术。研究结果表明,沉水植物恢复区产甲烷菌OTU类型均数为13种,高于沉水植物匮乏区域的9种;并且沉水植物恢复区的Shannon指数、Simpson多样性指数较对照区分别高21.7%和9.5%,表明沉水植物的恢复有利于提高沉积物中产甲烷菌群落结构多样性。就产甲烷菌种类而言,沉水植物的恢复对甲烷微菌纲Methanomicrobia等影响不显著,恢复区和匮乏区分别占43.6%—67.4%、41.5%—58.1%。甲烷球菌纲Methanococci在沉水植物恢复区和匮乏区的存在量较少,分别占1.7%和4.1%。而沉水植物的恢复一定程度上提高甲烷杆菌纲Methanobacteria的比例,较匮乏区高14.6%,且仅在恢复区检测到甲烷杆状热菌科Methanothermaceae和甲烷八叠球菌科Methanosarcinaceae。

In this study, we investigated the impacts of submerged macrophytes rehabilitation（SMR） on the methanogenic community structure in the lake sediments. We compared the diversity and structure of methanogenic populations between the SMR areas and the plant scarce areas in the West Lake of Hangzhou by using restriction fragment length polymorphism（PCR-RFLP） and molecular cloning techniques. The results showed that the average OTU type number in the SMR areas was 13, and the number was 9 in the scarce areas. Shannon-Weaver diversity and Simpson＇s evenness in the SMR areas were 21.7% and 9.5% respectively, which were higher than those in the control areas. This indicated that the diversity of the methanogenic community structure could be improved by the rehabilitation of submerged macrophytes. The in-depth analysis suggested that SMR had no significant effect on Methanomicrobia that accounted for 43.6%—67.4% and 41.5%—58.1% in the SMR areas and the scarce areas respectively. Methanococci was rare in both the SMR areas（1.7%） and the scarce areas（4.1%）. We also found that the proportion of Methanobacteria in the SMR areas was 14.6% higher than in the scarce areas. Methanothermaceae and Methanosarcinaceae were only detected in the SMR areas.