Dive 05: Gounod Seamount
September 11, 2017
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Dive 05: Let's Go Swima

While exploring Gounod Seamount at 2,800 meters (1.7 miles), the team encountered this swimming polychaete, which belongs to the aptly named genus, Swima. This worm has bioluminescent organs that can be released as a defense mechanism. Video courtesy of the NOAA Office of Ocean Exploration and Research, Deep-Sea Symphony: Exploring the Musicians Seamounts. Download (mp4, 25.4 MB)

The purpose of Dive 05 was to survey one of a series of small terraced features close to the summit of Gounod Seamount, characterize the distribution and abundance of benthic fauna, and to collect rock samples that can be used to determine the age and geochemistry of the feature. Remotely operated vehicle Deep Discoverer (D2) reached the base of the summit at a depth of 2,908 meters (9,540 feet). The team observed a talus slope consisting of various sizes of broken rock with sediment interspersed. A talus rock sample was collected from the landing area. Dead sponge stalks abounded, although few living animals were observed. As the dive continued, geological observations included alternating intact pillow flows, talus, and sheet flows. Biological observations included sparsely distributed sponges and corals, a polychaete, snails, a squat lobster, various fish, and a sea spider measuring nearly 30 centimeters (one foot) in diameter. While the steep wall did not harbor as dense of community as observed at shallower depths on other seamounts, there was a relatively high diversity and abundance organisms present in comparison to other dives at these depths. In the end, more living sponges were observed than corals, and there actually was an impressive abundance of diversity of life, with over 50 different organisms observed. The dive was slightly shortened due to escalating weather state and D2 left bottom at a water depth of 2,633 meters (8,638 feet).