| Project/Area Number |
05640720
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
生態
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| Research Institution | National Institute for Environmental Studies |
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Principal Investigator |
NAKAMURA Yasuo National Institute for Environmental Studies, Coastal Environment Research Team, Senior Researcher, 地域環境研究グループ, 主任研究員 (00132853)
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| Project Period (FY) |
1993 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1995: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1994: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1993: ¥700,000 (Direct Cost: ¥700,000)
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| Keywords | Heterotrophic dinoflagellates / Red tides / Microzooplankton / Microbial loop / Ingestion / Growth / 赤潮 / Microbial Loop |
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| Research Abstract |
Ecological roles of heterotrophic dinoflagellates (h-dinos) were investigated based on laboratory culture experiments, field observations and field experiments. In laboratory culture experiments, culture of a h-dinos, Gyrodinium dominans was established and growth and grazing of this species fed 18 species of phytoplankton were examined.G.dominans ingests particles with ESD of 15 um more effectively than those with ESD of ca.5 um. These results also suggested that G.dominans can play a major role in the disappearance of red tides by Gymnodinium mikimotoi (ESD = 15 um).
In the summer of 1995, population of G.dominans and a red tide flagellate, G.mikimotoi was monitored daily in the Seto Inland Sea. Following the outbreak of G.mikimotoi red tide, the abundance of G.mikimotoi increased rapidly by ingesting the red tide cells. In situ growth rate of G.dominans also increased drasticlaay just after the outbreak. These results, together with those obtained in laboratory cultures indicated that heterotrophic dinoflagellates playd major roles in the disappearance of the red tide and in controlling phytoplankton production in eutrophicated coastal area.
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