Metagenome or environmental sample from deep-underground water metagenome

500 liters of water were collected using in-line 0.1 μm Millipore® polycarbonate filters (47 mm diameter) in a Pall® polycarbonate filter housing directly attached to the tap, providing biomass for DNA extraction. Total DNA was extracted using the UltraClean™ Water DNA Isolation Kit (MoBio Laboratories; Carlsbad, CA USA). The resulting DNA was preserved at -20°C until further use. Approximately 1μg of total genomic DNA was submitted to the Marine Biological Laboratory (Woods Hole, MA) where metagenomic libraries were constructed and sequenced using an Illumina HiSeq platform (2 × 110 paired ends).