"the steep descent of the seabed from the continental shelf to the abyssal zone"@en-us . . . "108677912"@en-us . . "continental slope"^^ . "09255343-n"^^ . . "continental slope"@en-us . "bathyal zone"@en-us . . "0"^^ . "bathyal district"@en-us . "109255343"^^ . . . "106693841"@en-us . . . . "0"^^ . .