First scientific dives of the Nereid Under Ice hybrid ROV in the Arctic Ocean.

Tuesday, 16 December 2014: 3:10 PM
Christopher R German1, Antje Boetius2,3, Louis L Whitcomb4, Michael Jakuba1, John Bailey1, Christopher Judge1, Christopher McFarland4, Stefano Suman1, Stephen Elliott1, Christian Katlein3, Stefanie Arndt3, Andrew Bowen1, Dana Yoerger1, James C Kinsey1, Larry Mayer5, Marcel Nicolaus3, Samuel Laney1, Hanu Singh1 and Ted L Maksym1, (1)WHOI, Woods Hole, MA, United States, (2)Max-Planck-Instutute for Marine Microbiology, Bremen, Germany, (3)Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research Bremerhaven, Bremerhaven, Germany, (4)Johns Hopkins Univ, Baltimore, MD, United States, (5)University of New Hampshire Main Campus, Durham, NH, United States
The first scientific dives of the new Nereid Under Ice (NUI) hybrid ROV were conducted in the Arctic Ocean in July 2014 on RV Polarstern cruise PS86, a German-US collaboration. NUI is the latest in a family of vehicles derived from the Nereus prototype, using a single optical fiber to provide real-time telemetry to and from a battery-powered vehicle allowing much greater lateral maneuverability relative to its support ship than a conventional ROV. During PS86, dives conducted in the Arctic Ocean (typical water depths ~4000m) were completed in >80% ice cover beneath multi-year ice that was typically 2-4m thick (increasing to depths of up to 20m beneath ridges). Dives extended up to 800m away from the ship and, over dive durations of approximately 5 hours each, covered survey tracklines of up to 3.7km at depths varying from “landing” on the underside of the sea-ice to maximum depths of 45m to conduct upward looking multibeam sonar mapping. Ultimately, the vehicle will be capable of both AUV and ROV mode operations at ranges of 10-20km away from the support ship and at up to 2000m water depth (including seafloor as well as under ice operations). During the current cruise, the following major science suites were utilized to prove a range of scientific capabilities of the vehicle in ice-covered oceans: multibeam mapping of rugged topography beneath multi-year sea-ice; video- and digital still photography of the under side of the ice, biota associated with the ice-water interface (algal material) and abundant fauna in the immediately underlying water column (ctenophores, larvaceans, copepods were all notable for their abundance in our study site over the Gakkel Ridge near 83N, 6W). Other scientific activities included: vertical profiles combining CTD data with a suite of biosensors to investigate the structure of primary productivity and biogeochemical cycling in minimally distrubed areas of the sunlit under-ice water column, revealing high stratification associated with meltwater formation; lateral surveys of radiance and irradiance (together with co-registered measurements on top of the same ice-floe on our last dive) to investigate light availability and variability as a function of ice-cover. We will present examples of each of these data sets, together with an outline of suggested future activities that NUI could pursue.