Fig. 3

Phylogeny of 116 genera present in ≥ 85% of the samples of each habitat (four macroalgae plus sediment and seawater controls) with ≥ 1% relative abundance in at least one sample. Phylogenies were calculated using RAxML with 1,000 rapid bootstrap replicates based on similarities of full-length 16S rRNA gene sequences of the corresponding genera from SILVA NR Ref v138. Nomenclature: H = Gelidium sp., R = Grateloupia sp., L = Ulva sp., B = Saccharina sp., S = seawater, N = sediment, 1 = autumn, 2 = winter, 3 = spring, 4 = summer. Core phycosphere genera (present on all macroalgae) are highlighted by solid black triangles, and dominant phycosphere genera (present on three macroalgae) by solid black circles. Numbers in the six rightmost columns represent numbers of draft genomes (DGs) and MAGs obtained from all six habitats