Ecosystem and Oceanographic Structure in the Indian Sector of the Antarctic Ocean

Three cruises by T/V Umitaka-Maru were conducted in the Indian sector of the Antaractic Ocean in 2002/03，2004/05，2005/06austral summer。Survey areas were the eastern shelf of Keruguelen plateau and off Wilkes Land，off Lutzow-Holm Bay and off Wilkes Land off Luzow-Holm Bay，respectively.Main themes were the circulation of deep water formed off Adelie Land，the relationships between surface ecosystems and physical and chemical environments and the relationships between surface ecosystems and mesopelagic ecosystems.Hydrographic observations were conducted by using ship mount ADCP，CTD and LADCP，and seawater was sampled from various depths for macro-nutrient and trace metal analyses.Bio-optical observations，measurements of primary production and collections of surface phytoplankton and zooplankton by a plankton net and mesopelagic organisms by a multiple opening/closing trawl were also conducted。Aerosol observations were carried out off Luzow-Holm Bay，coincide with those fro…More m the Showa Station。A Continuous Plankton Recorder was towed during cruising from each port to observation area for the study on the long term change of surface plankton communities in combination with samples collected by R/V Aurora Australis and R/V Shirase.Until now，papers on following topics have been published：on the pathway and volume of deepwater formed off Adelie Land；on the remote sensing obollowing topics have been published：on the pathway and volume of deepwater formed off Adelie Land；Inter-annual changes in community composition and biomass of zooplankton along 140°E meridian related to the development of the Antarctic Divergence and the meander of the Antarctic Circumpolar Current were elucidated and some of the results will be submitted soon。Analyses of trace metals，aerosols and photosynthetic pigments are still undergoing.Mesopelagic organisms have been sorted into major taxa and detailed studies are also still undergoing.Less：Less

Three cruises by T/V Umitaka-Maru were conducted in the Indian sector of the Antaractic Ocean in 2002/03, 2004/05, 2005/06 austral summer. Survey areas were the eastern shelf of Keruguelen plateau and off Wilkes Land, off Lutzow-Holm Bay and off Wilkes Land and off Luzow-Holm Bay, respectively. Main themes were the circulation of deep water formed off Adelie Land, the relationships between surface ecosystems and physical and chemical environments and the relationships between surface ecosystems and mesopelagic ecosystems. Hydrographic observations were conducted by using ship mount ADCP, CTD and LADCP, and seawater was sampled from various depths for macro-nutrient and trace metal analyses. Bio-optical observations, measurements of primary production and collections of surface phytoplankton and zooplankton by a plankton net and mesopelagic organisms by a multiple opening/closing trawl were also conducted. Aerosol observations were carried out off Luzow-Holm Bay, coincide with those fro … More m the Showa Station. A Continuous Plankton Recorder was towed during cruising from each port to observation area for the study on the long term change of surface plankton communities in combination with samples collected by R/V Aurora Australis and R/V Shirase.Until now, papers on following topics have been published : on the pathway and volume of deepwater formed off Adelie Land ; on the remote sensing observations of eddies and annual variability of chlorophyll and sea-ice around the Antarctic Divergence ; on the parameters for precise estimation of Antarctic Krill biomass by quantitative echo-sounder. Inter-annual changes in community composition and biomass of zooplankton along 140゜E meridian related to the development of the Antarctic Divergence and the meander of the Antarctic Circumpolar Current were elucidated and some of the results will be submitted soon. Analyses of trace metals, aerosols and photosynthetic pigments are still undergoing. Mesopelagic organisms have been sorted into major taxa and detailed studies are also still undergoing. Less