腾格里沙漠东南缘不同生物土壤结皮细菌多样性及其季节动态特征

微生物多样性对于生物土壤结皮在沙漠生态系统中改善局部环境以及提升生态功能具有重要作用。本研究对腾格里沙漠东南缘沙坡头地区藻结皮、藓结皮及其下层的四季样品进行了16S rDNA高通量测序, 以期阐明细菌多样性及其在生物土壤结皮演替过程中的季节变化规律。结果表明4种类型样品的细菌丰富度在夏季显著低于其他3个季节。4种类型样品中主要的细菌类群为变形菌门、放线菌门、绿弯菌门、酸杆菌门、蓝细菌门等, 其中变形菌门和放线菌门为优势类群, 夏季时变形菌门的相对多度显著高于春季、秋季、冬季, 且在结皮层中相对多度显著高于结皮下层。放线菌门的相对多度在春季、夏季显著高于秋季、冬季, 且结皮下层相对多度高于结皮层。生物土壤结皮演替过程中细菌多样性及其相对多度季节动态变化表明其对沙漠土壤局部环境的变化作出了响应, 这为深入理解生物土壤结皮在沙漠生态系统中的生态功能提供了微生物多样性数据。

Diversity and seasonal dynamics of bacteria among different biological soil crusts in the southeast Tengger Desert

Microbial diversity plays important roles in improving local soil environment and ecological functions of biological soil crusts in desert ecosystems. In this study, high throughput sequencing of 16S rDNA was carried out to reveal the seasonal dynamics of bacterial diversity of algae crusts, moss crusts and their sublayer soils for four seasons during the evolution of biological soil crusts in the southeast Tengger Desert. The results showed that the bacterial richness of the sampled soils was significantly lower in summer than in the other three seasons. The main bacterial groups in the four soils were Proteobacteria, Actinobacteria, Chloroflexi, Acidobacteria and Cyanobacteria, of which Proteobacteria and Actinobacteria were the dominant groups. The relative abundance of Proteobacteria was significantly higher in summer than in spring, autumn and winter, and significantly higher in the biocrust samples than in the sublayers. The relative abundance of Actinobacteria was significantly higher in spring and summer than in autumn and winter, and significantly higher in sublayers of biocrusts than in biocrusts. The seasonal dynamics of bacterial diversity and relative abundance during the processes of biocrust succession indicate that it responds to changes in the local desert environment, which provides bacteria diversity data for understanding the ecological functions of biocrusts in the desert ecosystems.