Papahānaumokuākea ROV and Mapping expedition Dive 16 began in a high-density and high-diversity coral and sponge community that included numerous species of Chrysogorgia, Hemicorallium, and bamboo corals; Poliopogon, Stelodoryx, Farrea, and Bolosoma sponges; and a variety of smaller associates, including brittle stars, squat lobsters, mollusks, foraminifera, hydroids, and many other taxa. Throughout the dive, we observed rapid transitions between high-density, high-diversity communities to sparse, low-diversity communities that appeared to correlate with changes in seafloor geology and/or current strength.