Bacterial and archaeal diversity of two alkaline Indian hot springs, Jakrem (Meghalaya) and Yumthang (Sikkim), were studied. Thirteen major bacterial phyla were identified of which Firmicutes, Chloroflexi and Thermi were dominant in Jakrem and Proteobacteria in Yumthang. The dominant genera were Clostridium, Chloroflexus and Meiothermus at Jakrem (water temperature 46 °C, pH 9) and Thiobacillus, Sulfuritalea at Yumthang (water temperature 39 °C, pH 8) hot springs. The four Euryarchaeota taxa that were observed in both the hot springs were Methanoculleus, Methanosaeta, Methanosarcina and Methanocorposculum. Elstera litoralis, Thiovirga sp., Turneriella sp. were observed for the first time in association with hot springs along with Tepidibacter sp., Ignavibacterium sp., Teribacillus sp. and Dechloromonas sp. Individual bacterial phyla were found to be specifically correlated with certain physico-chemical factors such as temperature, dissolved SiO2, elemental S, total sulphide, calcium concentrations in hot spring water. Bacterial reads involved in sulfur cycle were identified in both16S rRNA gene library and sulfur metabolism may play key physiological functions in this hot spring. Members within Desulfobacterales and Thermodesulfovibrionaceae were identified and hypothesized their role in regulating sulfur cycle. The presence of many taxonomically unsolved sequences in the 16S rRNA gene tag datasets from these hot springs could be a sign of novel microbe richness in these less known hot water bodies of Northeastern India.
Keywords: Archaeal diversity; Bacterial diversity; Community composition; Hot spring; Illumina sequencing.