Abstract

Caves are semi-closed ecosystems that experience the absence of sunlight and often, poor organic matter conditions due to physical isolation. Therefore, microbial activity is a crucial factor for sustaining life in caves. However, the heterogeneity of microbial diversity and community structure in relation to different types of habitats in karstic caves (e.g., drip water residue, mineral deposits, rock varnish) remains largely unknown. In this study, cave deposit samples in various morphology were analyzed to reveal its bacterial and archaeal diversity of İnsuyu Cave in Burdur Province that is located in central Turkey. Illumina MiSeq sequencing of seven cave deposit samples (S1–S7) from the zones with a diverse array of environmental conditions revealed a total of four bacterial phyla including (1) Proteobacteria ranging from 80.20% to 98.72%, (2) Actinobacteria ranging from 0.23–13.03%, (3) Firmicutes ranging from 0.18 to 12.61% and (4) Bacteroidetes ranging from 0.00% to 3.80%, while none of the samples exhibits sign for archaeal life form. The heatmap diagram on abundance and distribution of the genera, referring to the results of 16S rRNA gene-based metagenomic analysis of the cave-dwelling microbial communities in İnsuyu Cave, revealed that the structures of the bacterial communities were significantly different across the samples (S1–S7). The high abundance of taxa that is relevant to anthropogenic activity revealed a strong impact of agricultural activity on the bacterial composition of İnsuyu Cave.

摘要

洞穴是半封闭的生态系统，缺乏阳光，通常由于物理隔离而有机质条件差。因此，微生物活动是维持洞穴生命的关键因素。然而，与岩溶洞穴中不同类型栖息地（例如滴水残渣、矿床、岩漆）相关的微生物多样性和群落结构的异质性在很大程度上仍然未知。在这项研究中，对各种形态的洞穴沉积物样本进行了分析，以揭示位于土耳其中部布尔杜尔省 İnsuyu 洞穴的细菌和古菌多样性。Illumina MiSeq来自具有多种环境条件的区域的七个洞穴沉积物样本（S1-S7）的测序显示总共有四种细菌门，包括（1）范围从 80.20% 到 98.72% 的变形菌，（2）范围从 0.23-13.03 的放线菌%, (3) Firmicutes 范围从 0.18% 到 12.61% 和 (4) Bacteroidetes 范围从 0.00% 到 3.80%，而没有一个样本显示出古细菌生命形式的迹象。属的丰度和分布的热图，参考了印苏玉洞穴洞穴微生物群落的基于 16S rRNA 基因的宏基因组分析结果，显示细菌群落的结构在样品之间存在显着差异（S1 -S7）。