| Project/Area Number |
63043058
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| Research Category |
Grant-in-Aid for Overseas Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Field Research |
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| Research Institution | University of the Ryukyus |
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Principal Investigator |
NISHIHIRA Moritaka Faculty of Science, Professor University of the Ryukyus, 理学部, 教授 (80004357)
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| Co-Investigator(Kenkyū-buntansha) |
SURAPHOL SUD チュラロンコン大学, 理学部, 助教授
SAKAI Kazuhiko Sesoko Marine Science Center, Instructor University of the Ryukyus, 熱帯海洋科学センター, 助手 (50153838)
KAMURA Shintoku Sesoko Marine Science Center, Professor University of the Ryukyus, 熱帯海洋科学センター, 教授 (90044982)
TSUCHIYA Makoto Faculty of Science, Associate Professor University of the Ryukyus, 理学部, 助教授 (40108460)
YAMAZATO Kiyoshi Faculty of Science, Professor University of the Ryukyus, 理学部, 教授 (80044973)
SUDARA Suraphol Faculty of Science, Assistant Professor Chulalongkorn University
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1988: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | The Gulf of Thailand / Non-reefal Coral Community / Environmental Heterogeneity / Diadema Grazing / Coral-associated Animals / サンゴの無性生殖 |
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| Research Abstract |
In the Sichang Islands, the Gulf of Thailand, intensive field studies were conducted for the non-reefal coral communities and the benthic communities on the sandy substrates adjacent to the coral zone. Our final target is to explain why the coral reefs have not been constructed in the turbid waters even in the tropical seas. Intensive mapping studies of the spatial arrangements and size compositions of the constituent corals in the Porites-dominated coral communities and detailed analysis of the competitive species interactions were conducted. The results, otgether with the observations of the great abundance of Diadema and boring animals, suggested the important roles of the grazing as well as boring animals in the non-reefal coral community structuring process. Our findings suggest that it is important and indispensable to explain why the super abundance of Diadema and other grazers and a variety of boring organisms can be maintained in the suspension-rich turbid waters in the bay environment. On the sandy bottom, we studied the distribution and abundance, and analyzed the ecological role of the sea urchins in the creation of environmental heterogeneity by field survey and field experiments. it was very striking that the continuous feeding activity of a spatangoid urchin, Brissus latecarinatus, creates bottom irregularities by making a funnel (with coarse sands and gravels) and a mound (with fine sands). The role of this urchin is very important for structuring the benthic microhabitats which were proved to support different benthic communities. The other remarkable point of the sandy bottom is the great abundance of free-living corals. Of these, Diaseris fragilis was studied for its distribution, population structure, and asexual reproduction by means of natural autotomy.
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