Cultivation and Molecular Studies to Reveal the Microbial Communities of Groundwaters Discharge Located in Hungary

In the present study 12 water samples of five sampling sites (Tatabánya, Dandár, Szentendre, Szent Flórián and Ciprián groundwaters) known as nutrient-depleted aquatic environments were studied using amplicon sequencing (NGS) cultivation techniques. Diversity indices cell counts determined to assess species richness in relation within samples, oligocarbophile growth capability isolated bacteria was tested microtiter plates. Altogether, 55 bacterial phyla identified from by sequencing. The microbial communities different times same did not differ significantly. Patescibacteria Proteobacteria all samples. sample dominated Bacteroidetes, while Dandár a high ratio Chloroflexi detected. Rokubacteria WOR-1 Tatabánya had number Epsilonbacteraeota. Nine archaeal also detected; characterized presence unclassified archaea Nanoarchaeota, among them Woesearchaeia, most dominant. Crenarchaeota Altiarchaeota detected ratios Among Thaumarchaeota family Nitrosopumilaceae, orders Nitrosotaleales Nitrososphaerales appeared Key organisms biogeochemical cycles discovered these environments: methanogenic archaea, methanotrophic bacteria, ammonia oxidizer, nitrate reducers, diazotrophs, sulfate sulfur oxidizer. show negative correlation case positive sample. diversity Szentendre are connected low counts, probably due vulnerability groundwaters external environment factors which lead infiltration soil microbes contaminants water. affiliated into four phyla, belonging (59%) followed Actinobacteria (21%), Firmicutes (17%) Verrucomicrobia (1%). members facultative chemolithotrophic genera Sphingobium, Sphingomonas, Sphingopyxis characterizing only Only 10% showed an obligate character. From novel taxa cultivated. As conclusion, our results confirmed predominance unknown subsurface water, pointing importance necessity further studies characterize populations.