Abundance and composition of ammonia-oxidising bacteria and archaea of a degraded lake wetland, Inner Mongolian Plateau, China

作者：Wu, Linhui; Hui, Lihua; Wang, Xiaoyi; Li, Jingyu; Yu, Jingli; Zhao, Ji^*

来源：Soil Research, 2013, 51(6): 554-560.

DOI：10.1071/SR13160

• abundance
• ammonia monooxygenase
• ammonia-oxidising archaea (AOA)
• ammonia-oxidising bacteria (AOB)
• diversity
• wetlands

Wetlands are one of the most highly threatened ecosystems on Earth, and their loss and degradation are regarded as major environmental problems. The degradation rate of lake wetlands of the Huitengxile grassland, Inner Mongolia, has increased over recent years. In this study, soil samples were collected in a degraded lake wetland of the Huitengxile grassland. The abundance and composition of soil ammonia-oxidising bacteria (AOB) and ammonia-oxidising archaea (AOA) were assessed by quantitative real-time PCR, cloning, and sequencing approaches. Four sampling sites were selected according to the order of water withdrawal. The lakeshore sample appeared to have the highest copy numbers of AOB amoA genes, and the lowest AOB population size was found in the lakebed sample. Similar to AOB, the AOA were most abundant in the lakeshore sample, and the population size in the lake centre sample was the lowest. Ex2cept in one lakebed sample, AOB were more abundant than AOA in all other samples, with AOB to AOA ratios ranging from 11 to 13. Phylogenetic analysis of the amoA gene fragments showed that all AOB sequences from different sites were affiliated to class -Proteobacteria, order Nitrosomonadales, family Nitrosomonadaceae and can be grouped into two clusters. Little difference was found in AOB community composition among different samples, which indicated that AOB community composition was stable during the drying process of the degraded lake. However, the AOA community compositions were very different between samples. All AOA sequences fell into four clusters. Cluster 1 was dominant in the sample from the centre of the lake, and cluster 2 was dominant in the lakeshore sample, indicating a difference in the community composition of AOA in response to the drying up of the lake. No clear relationship was found between the AOA and AOB community populations and soil physio-chemical properties. This study suggested that the AOA community in wetland systems is more sensitive than the AOB community to the drying process of the wetland ecosystem.

• 出版日期2013
• 单位内蒙古大学; CSIRO