SRX4928337 Glaciar Sample 3b-18S_S96_L001_R2_001 SRP137588 PRJNA430179 Purified DNA was quantified and 1ng of input DNA was used in a first PCR of 20 cycles with Q5 Hot Start High-Fidelity DNA Polymerase (New England Biolabs) in the presence of 100nM primers for 16S and 18S amplification (Table S1). After the first PCR, a second PCR of 15 cycles was performed with Q5 Hot Start High-Fidelity DNA Polymerase (New England Biolabs) in the presence of 400nM of primers (5'-AATGATACGGCGACCACCGAGATCTACACTGACGACATGGTTCTACA-3' and 5'-CAAGCAGAAGACGGCATACGAGAT-[10 nucleotides barcode]-TACGGTAGCAGAGACTTGGTCT-3') of the Access Array Barcode Library for Illumina Sequencers (Fluidigm). The finally obtained amplicons were validated and quantified by Bioanalyzer and an equimolecular pool was purified using AMPure beads and titrated by quantitative PCR using the Kapa-SYBR FAST qPCR kit for LightCycler 480 and a reference standard for quantification. The pool of amplicons were denatured prior to be seeded on a flowcell at a density of 10pM, where clusters were formed and sequenced using a MiSeq Reagent Kit v3, in a 2x300 pair-end sequencing run on a MiSeq sequencer to obtain 100000 reads per sample aproximately. Genomic data were analyzed with Base Space platform. SRS3125555 SAMN08367430 Glaciar Sample 3b-18S_S96_L001_R2_001 RNA-Seq METAGENOMIC PCR Illumina MiSeq