2000 Fiscal Year Final Research Report Summary
Mixing processes on the ecosystem of the Izu ridge
| Project/Area Number |
10045026
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Meteorology/Physical oceanography/Hydrology
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| Research Institution | TOKYO UNIVERSITY OF FISHERIES |
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Principal Investigator |
YAMAZAKI Hidekatsu Tokyo University of Fisheries, Department of Ocean Sciences, Associate Professor, 水産学部, 助教授 (80260537)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIDA Jiro Tokyo University of Fisheries, Department of Ocean Sciences, Associate Professor, 水産学部, 助教授 (30174931)
NAGASHIMA Hideki Tokyo University of Fisheries, Department of Ocean Sciences, Professor, 水産学部, 教授 (10087570)
MATSUYAMA Masaji Tokyo University of Fisheries, Department of Ocean Sciences, Professor, 水産学部, 教授 (00092594)
ISHIMARU Takashi Tokyo University of Fisheries, Department of Ocean Sciences, Professor, 水産学部, 教授 (90114371)
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| Project Period (FY) |
1998 – 2000
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| Keywords | turbulence / mixing / plankton |
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| Research Abstract |
We have conducted a series of field observations along the Izu ridge in order to investigate the role of mixing induced from an isolated island due to Kuroshio on the planktonic ecosystem. We have developed a new microstructure free fall profiler, Turbulence-ocean Microstructure Acquisition Profiler (TurboMAP), to measure both turbulence and chlorophyll field simultaneously. We also used a towed hydrographic instrument, Aquashuttle, to map the hydrography of the upper ocean. We studied three islands during the grant period. The first is Oshima, which locates at the northern end of the Izu ridge. Kuroshio extends the branches of the flow around this island. We have identified three distinguished hydrographic patterns : eastward stream, westward stream and no branch effect. All three cases had a common feature being the eastern part of the island showed higher chlorophyll level than the eastern part.
We surveyed Mikura-island as the second investigation site. Aoga-shima is the third inves
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tigation island. Both island locate the southern end of the Izu ridge and Kuroshio hits the island directly. In October 1999, we measured the hydrography of Mikura-island and dropped a few TurboMAP profiles. Unfortunately, the winch designed of TurboMAP during this experiment was not suited for this type of open ocean operation, we did not have sufficient information to get the global picture of the mixing event. In October 2000, we improved the winch system and the cable for TurboMAP.During this experimental period Kuroshio directly hit Aoga-shima. Although the weather was hash, we made successful microstructure measurements behind the island.
In order to the level of understanding on the coupling between mixing and planktonic ecosystem, the head investigator (HI) has collaborating with numerous people from the north America. The HI studied the interaction between turbulence and planktonic organisms using a video system with collaborators from Woods Hole oceanographic institution. The HI also review the coupling problems for small scale physical processes and planktonic organism with collaborators from University of Victoria and Institute of Ocean Science of Canada. Less
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