The ocean depths include a numberof distinct habitats. Immediately below the epipelagic lies the
mesopelagic,
or“middle pelagic,”
zone
(Fig. 16.1). Theepipelagic is roughly equivalent to the
photic zone,
the surface layer down to150 to 200 m (500 to 650 ft) where thereis enough light to support primary pro-duction by photosynthesis