Activities of the 52nd Japanese Antarctic Research Expedition during the RT/V Umitaka-Maru Cruise (UM-10-04)

Abstract

A marine science cruise was undertaken during December 2010 and January 2011 on board the Research and Training Vessel Umitaka-Maru, operated by Tokyo University of Marine Science and Technology (TUMSAT), to accomplish projects of the six-year plan Phase VIII of the Japanese Antarctic Research Expeditions (JARE-52 to -57). The projects and the cruise were planned to investigate the responses of Antarctic marine ecosystems to environmental changes related to global warming and oceanic acidification, and to study plankton community structure and environmental parameters. One of the main aims of the projects was to clarify the life cycle and physiology of plankton with shells of calcium carbonate (e.g., pteropods and coccolithophores), because these plankton are regarded to be the most sensitive to oceanic acidification. We performed net castings to qualitatively estimate the vertical distribution of plankton, made hydrographical observations, took measurements of dissolved inorganic carbonates in seawater, deployed a year-around mooring with sediment traps, made observations of a surface drifting buoy with a sediment trap and sensors to measure environmental parameters, and performed onboard acidified culture experiments using pteropods. The RT/V Umitaka-Maru departed from Fremantle, Australia, on 24 December 2010, cruised to the study area around the marginal sea ice zone (along 110°E and 140°E), and returned to Hobart, Australia, on 22 January 2011. The cruises by the icebreaker Shirase (JARE-52) in December 2010 and March 2011 followed the same study area as that described above, along 110°E, in order to perform repeat observations.