土壤氨氧化细菌对大气CO_2浓度增高的响应

Response of soil ammonia-oxidizing bacteria to enriched atmospheric CO_2.

利用FACE(free aircarbondioxideenrichment,开放式空气CO2浓度增高)试验平台,研究大气CO2浓度增高对土壤氨氧化细菌的数量、优势菌群及其硝化活性的影响。结果表明,大气CO2浓度增高时,土壤氨氧化细菌的数量在常氮水平上趋于减少,而在高氮水平上与对照没有差异。大气CO2浓度增高对土壤氨氧化细菌的优势菌群也产生明显影响。CO2浓度增高条件下,亚硝化球菌(Nitrosococcussp )和亚硝化弧菌(Nitrosovibriosp )是优势菌属;而在对照条件下,亚硝化单胞菌(Nitrosomonassp )和亚硝化球菌(Nitrosococcussp )是优势菌属。另外,CO2浓度增高条件下优势菌株的硝化活性也有不同程度的减弱。

A FACE system(free-air carbon dioxide enrichment)was used to investigate effects of elevated atmospheric CO_2 on soil ammonia-oxidizing bacterial population,dominant bacteria and their nitrification activities.It was found that the enrichment of atmospheric CO_2 reduced the population of ammonia-oxidizing bacteria in soil when N was in normal level,but had no difference when N was in high level.The elevation of atmospheric CO_2 also affected dominancy of ammonia-oxidizing bacteria with Nitrosococcus sp.and Nitrosovibrio sp. replacing Nitrosomonas sp. and Nitrosococcus sp.in the ambient soils.In addition,nitrification activities of the dominant genera were decreased to various extents under elevated CO_2.