“…In this study, we have examined the distribution and abundance of fusobacterial members in the Black Sea water column. The Black Sea is the largest permanent anoxic basin on Earth, with a maximum depth of approximately 2200 m. The Black Sea deep waters (>2000 m) are characterized recalcitrant nutrient conditions (i.e., the presence of difficult to degrade sulfurized dissolved organic matters; Gomez-Saez et al, 2021), elevated hydrostatic pressure and high sulfide concentration (400 μM; Volkov and Neretin, 2007), conditions that are expected to harbour microorganisms adapted to deal with those conditions (e.g., Vetriani et al, 2003;Wakeham et al, 2003Wakeham et al, , 2007Lin et al, 2006;Leloup et al, 2007;Henkel et al, 2019;Yadav et al, 2020;Suominen et al, 2021aSuominen et al, , 2021b. Here, we have successfully enriched members of the genus Psychrilyobacter (up to 58% of the total microbial community) of the phylum Fusobacteria and isolated two representative strains (Psychrilyobacter sp.…”