Diversity and distribution of ammonia-oxidizing Archaea in the seasonally frozen soils in Northeastern China

The genetic diversity and distribution of ammonia-oxidizing Archaea (AOA) in nine seasonally frozen soils sampled around the city of Harbin, China, is analyzed based on archaeal amoA gene. Soil samples are divided into four groups by its properties: fertilized/unfertilized mesic (well-balanced supply of moisture) soils and fertilized/unfertilized hydric (abundant of moisture) soils. Clone libraries based on AOA amoA gene polymerase chain reaction products are constructed, and the phylogenetic analysis at 5 % cutoff level shows that AOA members mainly belong to the soil/sediment lineage which includes four clusters, and very few archaeal amoA gene sequences fall into the marine lineage. The four groups of soils have different archaeal amoA gene assemblage, and the available nitrogen and organic carbon are significantly correlated with diversity indexes. The result shows that long-term artificial amendment such as fertilization and agriculture cultivation has an important impact on AOA community shift in terrestrial environment. Moisture may drive the shape of different AOA communities by changing the aerobic environment into anaerobic. Soil composition is another noticeable factor effect AOA community, which can help the shape of a special AOA community with only two species.