(a.) Relating to the deepest zone or region of the ocean.

Bassalian abyssal aquatic balneal bathyal bathybic bathymetric bathyorographical bathypelagic bathysmal benthal benthonic benthopelagic blue-water deep-water estuarine grallatorial hydrographic littoral marine maritime natant natatorial natatory nautical oceanic oceanographic pelagic seashore shore swimming terriginous thalassic tidal water-dwelling water-growing water-living water-loving