Fig. 3. Microbial communities represented three water column depth groupings: shallow (0–32 m), middle (40–70 m), and deep (80–95 m).

A Principal components analysis shows communities were highly similar within each depth grouping regardless of the sampling date. B Community composition of representative samples from each of the three depth groupings show both middle and deep water column layers feature high levels (~40% frequency) of a single taxon, the ammonia-oxidizing Nitrosopumilus sp. in the middle water column and the Woesearchaeota in the deepest layers. Samples shown here are from September 2019 at 30 m, 40 m, and 85 m. A taxon is defined as the sum of all SVs classified at the indicated level. Taxa comprising the “Other” category (<5% relative abundance) included Ca. Actinomarina, Rhodospirillales AEGEAN-169 marine group, and SAR202 in the 10 m sample; the alphaproteobacterial family Rhodobacteraceae in the 40 m sample; and the Patescibacterial phylum ABY1 in the 85 m sample.