| Project/Area Number |
14405038
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | National Institute of Polar Research |
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Principal Investigator |
ODATE Tsuneo National Institute of Polar Research, Division for Research and Education, Professor, 研究教育系, 教授 (60224250)
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| Co-Investigator(Kenkyū-buntansha) |
HIRAWAKE Toru National Institute of Polar Research, Division for Research and Education, Research Associate, 研究教育系, 助手 (70311165)
WATANABE Shuichi Independent Administrative Institution, Japan Agency for Marine-Earth Science and Technology Mutsu Institute for Oceanography, Group Leader, むつ研究所研究グループ, グループリーダー (00167131)
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| Project Period (FY) |
2002 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥14,500,000 (Direct Cost: ¥14,500,000)
Fiscal Year 2005: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2004: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2003: ¥5,100,000 (Direct Cost: ¥5,100,000)
Fiscal Year 2002: ¥5,500,000 (Direct Cost: ¥5,500,000)
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| Keywords | Antarctic Ocean / Global environment / Time-serial observation / Green-house gasses / Biological production / dimethylsulfide / International collaboration (Australia : New Zealand) / Japanese Antarctic Research Expedition / 国際研究者交流 |
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| Research Abstract |
Dimethylsulfide (DMS) is the most abundant form of volatile sulfur in the ocean. According to the CLAW hypothesis (Charlson et al. 1987), marine DMS production may act as a climate regulatory mechanism via a feedback loop involving surface ocean temperature, phytoplankton, DMS, sulfate aerosol formation, and cloud albedo, although the existence of this feedback has not been proven. Recently, attention has been focused on assessing sinks and sources of DMS in the oceans and on the processes controlling the cycling of DMS in the marine environment. DMS is produced by the enzymatic cleavage of dimethylsulfoniopropionate (DMSP), an organic compound synthesized by many phytoplankton species. The objective of this study was to determine the influence of biological processes on DMS dynamics in the Antarctic Ocean during the summertime, based on the time-serial observations in the austral summers of 2002/03, 2003/04, and 2004/05. The field data collected in the present study was synthesized in 2005. The present results show that sloppy feeding by Antarctic krill, which is the dominant herbivorousis macrozooplankton of the Antarctic Ocean, a more likely mechanism for producing DMS and dissolved DMSP. Moreover growth phase seems to be related DMSP production by diatoms. This may result in the low concentrations of dissolved DMSP observed in the early stage of diatom blooms under natural conditions. Since these processes on biological production as well as DMS and DMSP production are seem to be affected by variations of sea ice distribution, further study must be required to fully understand the global environment change.
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