Core and abundant OTUs found in the Porphyra umbilicalis microbiome identified using V5V6 (Taxonomic level 2 = phylum, 3 = class, 4 = order, 5 = family, 6 = genus).

a19 OTUs (0.03 distance) shared between Fall, Winter & Lab Groups*present at ≥1% of all sequences on at least one blade (n = 12)*L ≥1% on a lab bladebOTUs (0.03 distance) with sequence abundance greater than 1% on both lab bladescOTUs (0.03 distance) with sequence abundance greater than 1% on at least 3 of the 10 winter (n = 5) and fall (n = 5) bladesDesignations of F = Fall, E = Evenly distributed between fall and winter, W = Winter refer to a ≥3× skew in sequence abundance toward that group.