The phrase "deep seafloor" refers to the bottom part of the ocean that is far beneath the surface. It is the ocean's floor in the deep, dark and often unexplored areas of the sea. Full definition
«Satellite radar data have given us a detailed picture of where natural seeps are concentrated across deep seafloor of the Gulf of Mexico,» said co-author Ian MacDonald, an oceanographer and professor at Florida State University. (sciencedaily.com)
Scientists have been bowled over by the diversity that has turned up in unexpected places, from crustaceans and worms on the deep seafloor to carnivorous sponges in the Antarctic Ocean. (discovermagazine.com)
But naturally as we explore more environments (the deep seafloor, for example), we discover organisms we have never encountered. (sciencenews.org)