has increased levels of chlorophyll aquatic layer deep chlorophyll maximum layer A subsurface layer in a water body, typically an ocean or lake, in which chlorophyll concentrations reach their maximum. envoPolar ORCID:0000-0002-4366-3088 Logical def is incomplete. Need to express the idea of maximum chlorophyll. This could follow a pattern like: X has_maximum_levels_of Y relative_to Z, i.e. DCM has_maximum_levels_of chlorophyll relative_to subsurface_aquatic_layer May also be useful to include has_decreased_levels_of light intensity relative_to surface aquatic layer Further discussion in Issue #126. DCM subsurface chlorophyll maximum layer The DCM may or may not indicate greater abundance of photosynthetic, chlorophyll-bearing cells, as shade-adapted cells may have a greater chlorophyll to biomass ration than surface variants. Further, some DCMs may be formed by the sinking of cells from surface zones or the subduction of surface waters, rather than through biotic, community-level processess.