Vertical distribution of bacterial communities in the Greater Khingan
Mountain permafrost region
Abstract
Soil microorganisms are crucial contributors to the function of
permafrost ecosystems, as well as the regulation of biogeochemical
cycles. However, little is known about the distribution patterns and
drivers of high-latitude permafrost microbial communities subject to
climate change and human activities. In this study, the vertical
distribution patterns of soil bacterial communities in the Greater
Khingan Mountain permafrost region were systematically analyzed via
Illumina Miseq high-throughput sequencing. Bacterial alpha diversity
varied significantly at different soil depths, and the bacterial
diversity and richness in the active layer were significantly higher
than in the permafrost layer. The relative abundance of the dominant
phyla Chloroflexi (17.92%–52.79%) and Actinobacteria
(6.34%–34.52%) was significantly higher in the permafrost layer than
in the active layer, whereas that of Acidobacteria (4.98%–38.82%)
exhibited the opposite trend, and the abundance of Proteobacteria
(2.49%–22.51%) generally decreased with depth. More importantly, the
abundance of microorganisms linked to human infectious diseases was
significantly higher in the permafrost layer according to Tax4Fun
prediction analysis. Redundancy analysis (RDA) showed that NH4+-N, TOC
and TP were major factors affecting the bacterial community composition.
Collectively, our findings provide insights into the soil bacteria at
different depths in high-latitude permafrost regions, as well as their
vertical distribution patterns and major environmental drivers, which is
key to grasping the response of cold region ecosystem processes to
global climate changes.