Shewanella sp. MR-4 and MR-7 are two isolates that were obtained from different depths of the Black Sea representing the oxic (5 m depth) and anoxic (60 m) zones of the water column (Venkateswaran et al. 1999). A comparative analysis will offer novel insights into the genetic basis of this intriguing physiological difference and the environmental stimuli that control it. Strains MR-4 and MR-7 will provide additional genomic information on the other phylogenetic branch of the S. baltica species.