The vast majority of the ocean floor is flat, soft, and featureless. Certain parts of the seafloor where we find ridges, seamounts, and escarpments contain substantial amounts of exposed hard-bottom surfaces. Unlike soft-bottom habitats, rocky substrates can allow for the colonization of many large organisms, including deepwater corals and sponges. These relatively stable rocky habitats allow some of these organisms to grow very old and large. This video from Dive 9 of the expedition shows some of the massive organisms that we find attached to hard, rocky substrates in the Caribbean Sea.

Text contributed by Steve Auscavitch, Temple University.