Pisciarelli hot springs marker gene sequencing

A combined geochemical and microbiological exploration in ten sampling points along a sharp temperature gradient (90-15 degrees C) within an extremely acidic hot springs (Pisciarelli Spring, Campi Flegrei area, Italy) show how the hydrothermal fluids influence the microbial dynamics. This area is characterized by high levels of reduced gaseous species (e.g. H2S, H2, CH4, CO), and very low pH. Thermodynamic calculations reveal a high microbial catabolic potential in N-, S-, and Fe-bearing species oxidation/reduction reactions. Archaea and Bacteria are present in almost equal cell abundance (up to 1.1 x 109 and 9.3 x 108 cell/g, respectively) in sampling points with temperature below 70 degrees C; on the contrary, high temperature sampling points (85-90 degrees C) are characterized by low abundance of archaeal cells. The high-throughput sequencing of 16S rRNA gene indicate strong differences in archaeal and bacterial communities composition along temperature gradient, but the core microbiome in this extreme environment is mainly constituted by chemoautotrophic microorganisms most likely involved in N-, S-, and Fe-bearing species transformations (e.g. Acidianus infernus, Ferroplasma acidarmanus, Acidithiobacillus), in line from thermodynamic calculations.