Dive 09: "West Palmyra Seamount"
May 10, 2017
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Dive 09: An Easy Meal

During Dive 09 on West Palmyra Seamount, scientists observed this unusual behavior of a sea star evidently eating a crinoid. Video courtesy of the NOAA Office of Ocean Exploration and Research, Mountains in the Deep: Exploring the Central Pacific Basin. Download (mp4, 17.2 MB)

Today we sent the remotel operated vehicles (ROVs) Seirios and Deep Discoverer to ~2,170 meters (~7,120 feet) deep on a site we called "West Palmyra Seamount." The bottom composition was mostly ferro-manganese (Fe-Mn) rock with some soft, light-colored sediment filling the spaces in between. We were greeted immediately by several small anemones attached to a large boulder with tentacles swaying in the current. Nearby were a corallimorph, a stalked sponge, a crinoid, and a black coral with near-perfect symmetry. As we moved along our dive track, we continued to find interesting organisms. Brittle stars clung to a bubblegum coral overgrown with zoanthids, and a rock pen gripped tenaciously to a Fe-Mn rock. Up ahead, two species of holothurians (sea cucumbers) feasted on sediment. Ripples in the sediment indicated currents in the area. Here, sea pens emerged from the sediment while tunicates and sponges were attached to the rocks. A shrimp scurried away from the lights of the ROVs – but not before we noted it for National Shrimp Day!

More crinoids, brittle stars, black corals, chrysogorgiids, and sea pens appeared. We saw urchins, polychaetes, a solitary hydroid, a carnivorous sponge, and a sea star feeding upon a crinoid. A shrimp and a cluster of barnacles were on a large rock. We found what appeared to be an octopus egg on a black coral while a squat lobster crawled on a different black coral nearby. A six-legged sea star used its tube feet to move slowly on a large Fe-Mn crusted rock. We came upon a bamboo coral whip. At this point in the dive, the wind had picked up considerably and we needed to bring the ROVs back to the surface for safety.