Seamounts (underwater mountains) make up a a huge cumulative habitat type in the ocean, and distinct biological communities can exist on the same underwater feature. As a part of an investigation by MBARI, Davidson Seamount and others offshore of California were surveyed with an ROV, and yielded some pretty spectacular underwater footage.
You can read more about this work at Davidson in this PLoS ONE article, authored by Dr. Craig McClain (of DSN notoriety) and colleagues. If you listen closely to the narration in the video, you’ll hear Lonny Lundsten, a coauthor on the study, mention the idea that seamounts, while providing unique habitat in the open ocean, are not necessary the hosts of endemic species (species that are restricted to a single geographic locale). More about that here.[video: MBARI on YouTube]