oceanic pelagic zone biome oceanic mesopelagic zone biome 2010-03-15T11:21:03Z ENVO ENVO:01000036 ORCID:0000-0002-4366-3088 The oceanic mesopelagic zone biome comprises regions of the marine water column that occur offshore, beyond a continental shelf. This biome extends through the water column from approximately 200-1000 m depth - the maximal depth of light penetration in all but the clearest oligotrophic ocean regions. In comparison to the epipelagic zone, dominant forms of pelagic organisms do not change very much; however, there are marked changes in species composition and the proportion of smaller-sized individuals decreases.