title: Partial nifH sequences from: DNA-150m-26.16 N 158.06 W-May-2016-small fraction-64098
design: Seawater samples were fractionated into the >3 micron and 0.2-3 micron size fractions during filtration. DNA was extracted using the DNeasy Plant Mini Kit with the QIAcube instrument, using extra freeze-fracture, bead-beating and proteinase K treatment steps. Partial nifH sequences were amplified from DNA using nested PCR with the universal primers of Zehr and McReynolds (1989) and Zani (2000). The second PCR included both gene-specific regions and common sequence tags (see Moonsamy et al. 2013). Successful PCRs (visualized by gel electrophoresis) were pooled and sent to the DNA Services Facility at the University of Illinois at Chicago. Here, a third PCR was performed to add sequencing adaptors and barcodes, and amplicons were purified, pooled, and sequenced using MiSeq Standard v.3, 2x300 paired-end sequencing as described by Gradoville et al. (2018).