A primary division of the sea that includes all of the ocean floor. The Benthic Division is subdivided into the Littoral System (the ocean floor lying in water depths ranging from the high watermark to a depth of 200 m or the edge of the continental shelf), and the Deep-Sea System (ocean floor lying in water deeper than 200 m). The systems are further subdivided into the Eulittoral Zone (0 to 50 m), Sublittoral Zone (50 to 200 m), Archibenthic Zone (200 to 1,000 m), and the Abyssal-Benthic Zone (1,000 m and greater).