title: Marine metabarcoding at a kelp farm in Scotland
design: Environmental DNA was amplified using a two-step PCR amplicon metabarcoding approach targeting the mitochondrial cytochrome c oxidase subunit I (COI) gene. In the first PCR, the 313 bp Leray-XT COI fragment was amplified using the mlCOIintF-XT and jgHCO2198 primer pair. Primers included partial adapter sequences to enable addition of Illumina indices in a second PCR. A limited-cycle second PCR was used to add dual Illumina barcodes. Indexed amplicons were pooled equimolarly and sequenced using paired-end Illumina sequencing (2  250 bp).