College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China.
Chinese Research Academy of Environmental Sciences, Beijing, 100020, China.
BMC Ecol Evol. 2022 Apr 30;22(1):54. doi: 10.1186/s12862-022-01986-y.
Karst tiankeng is a large-scale negative surface terrain, and slope aspects affect the soil conditions, vegetation and microbial flora in the tiankeng. However, the influence of the slope aspect on the soil microbial community in tiankeng has not been elucidated.
In this study, metagenomic sequencing technology was used to analyze the soil microbial community structure and functional potentials on the shady and sunny slopes of karst tiankeng.
The Shannon-Wiener diversity of microbial communities on shady slope (SHS) was significantly higher than that on sunny slope (SUS). Although the composition of dominant phyla on shady slope (SHS) and sunny slope (SUS) was similar, there were significant differences in beta-diversity. The linear discriminate analysis (LDA) results showed that biomarkers mainly belongs to Actinobacteria, Chloroflexi and Proteobacteria. Functional pathways and CAZy (Carbohydrate-Active Enzymes) genes also had a remarkable response to slope aspect change. LEfSe results indicated several biomarker pathways in sunny slope involved in human disease. Moreover, the abundance of CAZy genes was higher in shady slope and had stronger ability in decomposing litter. The microbial communities were mainly correlation with the vegetation characteristics (species richness and coverage) and soil properties (SOC and pH).
These results indicate slope aspect has a pronounced influence on microbial community composition, structure and function at karst tiankeng. In the future, the conservation of karst tiankeng biodiversity should pay more attention to topographical factors.
天坑是一种大型负地形地貌，坡向影响天坑中的土壤条件、植被和微生物区系。然而，坡向对天坑土壤微生物群落的影响尚未阐明。
本研究采用宏基因组测序技术，分析了岩溶天坑阴坡和阳坡土壤微生物群落结构和功能潜力。
阴坡（SHS）的微生物群落 Shannon-Wiener 多样性显著高于阳坡（SUS）。尽管阴坡（SHS）和阳坡（SUS）的优势门组成相似，但β多样性存在显著差异。线性判别分析（LDA）结果表明，生物标志物主要属于放线菌门、绿弯菌门和变形菌门。功能途径和 CAZy（碳水化合物活性酶）基因也对坡向变化有明显的响应。LEfSe 结果表明，阳坡的一些生物标志物途径与人类疾病有关。此外，阴坡 CAZy 基因的丰度较高，具有更强的分解凋落物的能力。微生物群落主要与植被特征（物种丰富度和盖度）和土壤特性（SOC 和 pH）相关。
这些结果表明，坡向对岩溶天坑微生物群落的组成、结构和功能有显著影响。在未来，天坑生物多样性的保护应该更加关注地形因素。
