16S rRNA gene amplicon sequencing of estuarian sediment cores and microcosms thereof originating from Rio Tinto, Huelva (Spain), 2022.

Rio Tinto (Huelva, Spain) is an acid rock drainage-affected fluvial estuarine system where Fe(II)-oxidizing microorganisms were shown to be active both in the water column and in the top sediment layer, contributing to Fe mineral accumulation in the estuarian sediment. DNA and RNA extracted from sediment cores were investigated for their microbial community with 16S rRNA amplicon sequencing. Additionally, microcosms of the oxic layer of the sediment cores were incubated and treated with sodium azide, lactate, nitrate and iron, or nitrate and iron and acetate. Microbial 16S rRNA genes were amplified using primers 515F and 806R targeting the V4 region. Library preparation steps (Nextera, Illumina) and sequencing were performed using Illumina MiSeq sequencing system (Illumina, USA) at the Institute for Medical Microbiology and Hygiene (MGM) of the University of Tuebingen (Germany).