Vertical: epipelagic (0–200 m, lit), mesopelagic (200–1000 m, twilight), bathypelagic (1000–4000 m, dark), abyssopelagic (4000–6000 m), hadopelagic (trenches, >6000 m). Horizontal: neritic (shelf) vs oceanic; benthic divisions track depth…
Vertical: epipelagic (0–200 m, lit), mesopelagic (200–1000 m, twilight), bathypelagic (1000–4000 m, dark), abyssopelagic (4000–6000 m), hadopelagic (trenches, >6000 m). Horizontal: neritic (shelf) vs oceanic; benthic divisions track depth…