what is the drop off in the ocean
Neritic zone In marine biology, the neritic zone, also called coastal waters, the coastal ocean or the sublittoral zone,[3] refers to that zone of the ocean where sunlight reaches the ocean floor, that is, where the water is never so deep as to take it out of the photic zone.[? or entire top-layer clarification needed] It extends from the low tide mark to the edge of the continental shelf, with a relatively shallow depth extending to about 200 meters (667 feet). Above the neritic zone lie the intertidal (or eulittoral) and supralittoral zones; below it the continental slope begins, descending from the continental shelf to the abyssal plain and the pelagic zone.
Seamount A seamount is a mountain rising from the ocean seafloor that does not reach to the water's surface (sea level), and thus is not an island, islet or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abruptly and are usually found rising from the seafloor to 1,000–4,000 m (3,300–13,100 ft) in height. They are defined by oceanographers as independent features that rise to at least 1,000 m (3,281 ft) above the seafloor, characteristically of conical form.[1] The peaks are often found hundreds to thousands of meters below the surface, and are therefore considered to be within the deep sea.[2] During their evolution over geologic time, the largest seamounts may reach the sea surface where wave action erodes the summit to form a flat surface. After they have subsided and sunk below the sea surface such flat-top seamounts are called "guyots" or "tablemounts"[1]