Composition of microbiome of nudibranch Doriopsilla fulva and associated samples

Samples of six nudibranchs Doriopsilla fulva collected from the same sampling site (Pillar Point tide pools, Half Moon Bay, California) in June 2017, November 2020, February 2021, May 2021 and July 2021 were characterized by 16S rDNA amplicon sequencing on Illumina MiSeq platform. DNA was extracted by alkaline lysis from homogenized tissues filtered through 5 um pore filters to enrich for the bacterial fraction. The sample set contained tissues from nudibranch mantle, gills, reproductive organs, digestive system and slime collected directly from the mantle surface or collected after overnight incubation in sterile seawater. We also analyzed seawater samples in which the nudibranchs were transported from the sampling site to laboratory (aprox. 2 hours) and a control seawater sample collected on a day when no nudibranchs were collected. The results indicated large compositional differences between nudibranch mantle microbiome, internal organs, slime and water samples.