高寒湿地甲烷氧化菌群落对模拟增温的响应

Response of methane-oxidizing bacteria communities to simulated warming in an alpine wetland

甲烷氧化菌能够氧化湿地生态系统产生的绝大部分甲烷,从而减缓温室效应.高寒湿地对气候变化极为敏感,但目前高寒湿地甲烷氧化菌群落对温度升高如何响应的相关研究较少.以青海湖高寒湿地为研究对象,利用开顶箱(open-top chamber,OTC)模拟增温实验,进一步通过高通量测序来探究温度升高后高寒湿地甲烷氧化菌群落结构及多样性的变化.结果显示,高寒湿地甲烷氧化菌群落的优势菌门为变形菌门;温度升高对高寒湿地甲烷氧化菌群落的多样性指数没有显著影响,但对甲烷氧化菌的群落结构作用显著. LEfSe分析表明,增温处理组与自然对照组共存在29个差异菌群,温度升高降低了属水平优势菌群的相对丰度.增温显著改变了3个优势菌属的相对丰度,甲基球菌属、甲基杆菌属的相对丰度显著降低,甲基弯曲菌属的相对丰度显著升高.高寒湿地甲烷氧化菌群落功能基团为21个,大多与碳、氮代谢过程密切相关.整体而言,对比高寒湿地甲烷氧化菌的群落多样性,其群落结构对温度升高更为敏感,部分菌群的相对丰度发生了显著变化.

Methane-oxidizing bacteria can oxidize most of the methane produced by wetland ecosystems,mitigating the greenhouse effect. Alpine wetlands are extremely sensitive to climate change;however, there are only a few studies on the response of methane-oxidizing bacterial communities to temperature rise in alpine wetlands. In this study, the alpine wetland of Qinghai Lake was investigated, an open-top chamber(OTC)simulation warming experiment was used, and the changes in community structure and diversity of methaneoxidizing bacteria in alpine wetlands after a temperature rise were investigated through high-throughput sequencing. The dominant phylum of the methane-oxidizing bacteria community in the alpine wetland was Proteobacteria. The temperature increase had no significant effect on the diversity index of the methane-oxidizing bacterial communities but had a significant effect on the community structure of methane-oxidizing bacteria. LEfSe analysis showed that there were 29 different microflorae between the warming and natural control groups, and the increase in temperature reduced the relative abundance of dominant microflora at the genus level. Warming significantly changed the relative abundances of the three dominant bacterial genera;the relative abundances of Methylococcus and Methylobacter were significantly decreased, while the relative abundance of Methylosinus was significantly increased. There were 21 functional groups in the methane-oxidizing bacterial community in the alpine wetland, most of which were closely related to carbon and nitrogen metabolism. In general, compared with the community diversity of methane-oxidizing bacteria in alpine wetlands, the community structure was more sensitive to temperature rise, and the relative abundance of some bacteria changed significantly.