Sea Technology

MAR 2013

The industry's recognized authority for design, engineering and application of equipment and services in the global ocean community

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One of the recovered Scopelocheirus schellenbergi amphipods from more than 8,000 meters in the Puerto Rico Trench. (Photo Credit: Toyonobu Fujii) Amphipod Location The samples recovered by 11k were Scopelocheirus schellenbergi, a species of lysianassoid amphipod that have so far only been found in ultradeep trenches. They are typically found in the deep subduction trenches of the Pacifc Ocean from the Aleutian Trench in the north Pacifc and the Kuril-Kamchatka, Japan, New Hebrides and the Tonga-Kermadec trenches, which run down the western Pacifc Rim. In these trenches S. schellenbergi has been found between 6,000 and 9,104 meters, the deepest of which came from the Kermadec Trench. The interesting point concerning the presence of this species in the Puerto Rico Trench is that there is no direct corridor of equivalent depth between the north and western Pacifc Trenches and the Puerto Rico Trench. This level of isolation offers a tantalizing question as to how the same species came to be in multiple trenches that are isolated from one another. Furthermore, the closest trench to the Puerto Rico Trench is the Peru-Chile Trench. Although thousands of amphipods were captured from 4,000 to 8,000 meters in 2010 by the Hadal Environmental Science Education Program (HADEEP), not a single S. schellenbergi was found. 20 st / MARCH 2013 Extending the Reach of Amphipod Research S. schellenbergi was frst discovered in the Puerto Rico Trench in 1948 when the Swedish vessel Albatross, under the leadership of Hans Pettersson, successfully bottom trawled between depths of 7,625 and 7,900 meters. Among other benthic fauna, the recovered amphipods were later described as S. schellenbergi by Russian scientists J.A. Birstein and M.E. Vinogradov in 1958. In the mid-1970s, a deep trawl was conducted in the trench to 8,800 meters, whereby six amphipods were collected but unfortunately were not identifed to species level. Similarly, two box cores from 8,560 meters were also obtained, recovering more than 30 unidentifed amphipod samples. Given the abundance of this species from the 11k deployment, it is likely that many of these samples were also S. schellenbergi. Technology capable of sampling at such depths is limited with two ROVs (Nereus at the Woods Hole Oceanographic Institution and Abismo at the Japan Agency for Marine-Earth Science and Technology, or JAMSTEC), one submersible (James Cameron���s Deepsea Challenger) and seven landers (four at Aberdeen University, two at the Scripps Institution of Oceanography and one at JAMSTEC). The 11k, particularly in its role as both AUV and ROV, adds to the global capability at these depths. Future Research The samples obtained by the 11k are of immense value to an ongoing sample archive. The HADEEP project has sampled multiple trenches around the Pacifc Rim over the past six years and has successfully performed nearly 40 deployments of cameras and traps in fve trenches from 4,000 to 10,000 meters (more than 30 of which are greater than 6,000 meters). Among these data is now the largest collection of amphipod samples from the ultradeep trenches. These samples are now available for genetic sequencing, allowing scientists to examine the genetic connectivity between these incredibly deep and isolated habitats.

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