Abstract

The abandoned Sitarjevec mine represents a specific environment (complete darkness; 10 °C) with waters of pH 3 and it contains various ores (e.g. lead, mercury, zinc, iron, copper) and many different minerals (e.g. anglesite, baryte, cinnabar, pyrite, cerussite, quartz, siderite). The aim of this study was to characterize the iron oxide/hydroxide speleothems that show rapid growth of up to 5 cm/year. Their morphological and chemical characterization showed that they have a layered structure with different ferrihydrite minerals (i.e. goethite, feroxyhyte, lepidocrocite). Scanning electron microscopy–energy dispersive X-ray spectrometry confirmed that the surface layers were very porous, while for the inner parts, the bulk was compact. Bacterial populations in these speleothems and their environment were analyzed using 16S rRNA sequencing. These data revealed a great diversity of bacteria, which included 19–34 phyla across different samples. Proteobacteria were dominant in all of the samples (60–95%), although the highest bacterial diversity was seen for a water sample from the base of the speleothem, with 670 different genera and 100 different species detected. Among these there were typical iron-oxidizing bacteria, like Gallionella capsiferriformans, Sideroxydans lithotrophicus, Sphingomonas echinoides, Candidatus Nitrotoga Nitrotoga, Leptospirillum ferrooxidans, and Ferrovum myxofaciens. These iron-oxidizing bacteria were not present in other samples from the mine. Therefore, these bacteria might be involved in the structural growth of these speleothems. The specific bacterial interactions with the minerals under the environmental conditions in the mine need to be further analyzed and evaluated.

摘要

废弃的Sitarjevec矿场具有特定的环境（完全黑暗； 10°C），pH为3的水，其中包含各种矿石（例如铅，汞，锌，铁，铜）和许多不同的矿物（例如角铁矿，重晶石，朱砂，黄铁矿，陶粒，石英，菱铁矿）。这项研究的目的是表征显示出每年高达5厘米的快速增长的氧化铁/氢氧化物鞘脂。它们的形态和化学特征表明它们具有不同的水铁矿矿物（针铁矿，铁矿铁，锂云母）的层状结构。扫描电子显微镜–能量色散X射线光谱法证实表面层非常多孔，而内部部分的体积很紧凑。使用以下方法分析了这些脾脏中的细菌种群及其环境16S rRNA测序。这些数据显示出细菌的多样性，其中包括不同样本中的19–34个门。在所有样品中，变形杆菌都占主导地位（60-95％），尽管从鞘翅目基地发现的水样中细菌多样性最高，共检测到670个不同属和100个不同物种。这其中有典型的铁氧化细菌，如嘉利翁氏菌capsiferriformans，Sideroxydans lithotrophicus，鞘氨醇echinoides，暂定Nitrotoga Nitrotoga，钩端螺旋体氧化亚铁硫杆菌和Ferrovum myxofaciens。这些铁氧化细菌在矿山的其他样品中不存在。因此，这些细菌可能参与这些脾细胞的结构生长。在矿山环境条件下，与矿物的特定细菌相互作用需要进一步分析和评估。