Acid mine drainage (AMD) harbors all three life forms in spite of its toxic and hazardous nature. In comparison to bacterial diversity, an in-depth understanding of the archaeal diversity in AMD and their ecological significance remain less explored. Archaeal populations are known to play significant roles in various biogeochemical cycles within the AMD ecosystem, and it is imperative to have a deeper understanding of archaeal diversity and their functional potential in AMD system. The present study is aimed to understand the archaeal diversity of an AMD sediment of Malanjkhand Copper Project, India through archaea specific V6 region of 16S rRNA gene amplicon sequencing. Geochemical data confirmed the acidic, toxic, heavy metal-rich nature of the sample. Archaea specific V6-16S rRNA gene amplicon data showed a predominance of Thermoplasmata (BSLdp215, uncultured Thermoplasmata, and Thermoplasmataceae) and Nitrososphaeria (Nitrosotaleaceae) members constituting ~ 95% of the archaeal community. Uncultured members of Bathyarchaeia, Group 1.1c, Hydrothermarchaeota, and Methanomassiliicoccales along with Methanobacteriaceae, Methanocellaceae, Haloferaceae, Methanosaetaceae, and Methanoregulaceae constituted the part of rare taxa. Analysis of sequence reads indicated that apart from their close ecological relevance, members of the Thermoplasmata present in Malanjkhand AMD were mostly involved in chemoheterotrophy, Fe/S redox cycling, and with heavy metal resistance, while the Nitrososphaeria members were responsible for ammonia oxidation and fixation of HCO 3 − through 3-hydroxypropionate/4-hydroxybutyrate cycle at low pH and oligotrophic environment which subsequently played an important role in nitrification process in AMD sediment. Overall, the present study elucidated the biogeochemical significance of archaeal populations inhabiting the toxic AMD environment.

中文翻译：

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Thermoplasmata 和 Nitrososphaeria 是印度 Malanjkhand 铜项目酸性矿山排水沉积物中的主要古菌成员

尽管酸性矿井排水 (AMD) 具有毒性和危险性，但它包含所有三种生命形式。与细菌多样性相比，对 AMD 中古菌多样性及其生态意义的深入了解仍然较少。众所周知，古菌种群在 AMD 生态系统内的各种生物地球化学循环中发挥着重要作用，因此必须更深入地了解古菌多样性及其在 AMD 系统中的功能潜力。本研究旨在通过 16S rRNA 基因扩增子测序的古菌特异性 V6 区域了解印度 Malanjkhand Copper Project AMD 沉积物的古菌多样性。地球化学数据证实了样品的酸性、有毒、富含重金属的性质。古细菌特定的 V6-16S rRNA 基因扩增子数据显示 Thermoplasmata（BSLdp215、未培养的 Thermoplasmata 和 Thermoplasmataceae）和 Nitrososphaeria（Nitrosotaleaceae）成员占古菌群落的 95%。Bathyarchaeia、1.1c 组、Hydrothermarchaeota 和 Methanomassiliicoccales 的未培养成员以及甲烷杆菌科、甲烷菌科、盐藻科、甲烷菌科和甲烷调节菌科构成了稀有分类群的一部分。对序列读数的分析表明，除了它们密切的生态相关性外，存在于 Malanjkhand AMD 中的 Thermoplasmata 成员主要参与化学异养、Fe/S 氧化还原循环和重金属抗性，而 Nitrososphaeria 成员负责氨氧化和 HCO 3 - 在低 pH 值和低营养环境下通过 3-羟基丙酸盐/4-羟基丁酸盐循环固定，随后在 AMD 沉积物的硝化过程中发挥重要作用。总体而言，本研究阐明了居住在有毒 AMD 环境中的古菌种群的生物地球化学意义。