Cryosphere Research Station on the Qinghai-Tibetan Plateau, State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resource, Chinese Academy of Sciences, Lanzhou, 730000, Gansu, China.
School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, China.
BMC Ecol. 2018 Aug 22;18(1):27. doi: 10.1186/s12898-018-0183-y.
Permafrost degradation may develop thermokarst landforms, which substantially change physico-chemical characteristics in the soil as well as the soil carbon stock. However, little is known about changes of bacterial community among the microfeatures within thermokarst area.
We investigated bacterial communities using the Illumina sequencing method and examined their relationships with soil parameters in a thermokarst feature on the northern Qinghai-Tibetan Plateau. We categorized the ground surface into three different micro-relief patches based on the type and extent of permafrost collapse (control, collapsing and subsided areas). Permafrost collapse significantly decreased the soil carbon density and moisture content in the upper 10 cm samples in the collapsing areas. The highest loading factors for the first principal component (PC) extracted from the soil parameters were soil carbon and nitrogen contents, while soil moisture content and C:N ratios were the highest loading factors for the second PC. The relative abundance of Acidobacteria decreased with depth. Bacterial diversity in subsided areas was higher than that in control areas.
Bacterial community structure was significantly affected by pH and depth. The relative abundance of Gemmatimonadetes and Firmicutes were significantly correlated with the first and second PCs extracted from multiple soil parameters, suggesting these phyla could be used as indicators for the soil parameters in the thermokarst terrain.
多年冻土退化可能会形成热喀斯特地貌，这会极大地改变土壤的理化特性和土壤碳储量。然而，对于热喀斯特区微地貌内细菌群落的变化，人们知之甚少。
我们利用 Illumina 测序方法调查了细菌群落，并研究了它们与青藏高原北部热喀斯特地貌土壤参数之间的关系。我们根据多年冻土塌陷的类型和范围，将地面分为三个不同的微地貌斑块（对照区、塌陷区和沉降区）。多年冻土塌陷显著降低了塌陷区上层 10cm 土壤样本的土壤碳密度和土壤含水量。从土壤参数中提取的第一主成分（PC）的最高载荷因子是土壤碳和氮含量，而第二 PC 的最高载荷因子是土壤水分含量和 C:N 比。酸杆菌的相对丰度随深度降低。沉降区的细菌多样性高于对照区。
细菌群落结构受 pH 值和深度的显著影响。芽单胞菌门和厚壁菌门的相对丰度与从多个土壤参数中提取的第一和第二 PC 显著相关，这表明这些门可以作为热喀斯特地形土壤参数的指示生物。
