1996 Fiscal Year Final Research Report Summary
Studies on non-dominancy of large diatoms and the mechanism for maintaining their populations in the pelagic ocean
| Project/Area Number |
06454009
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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 | 一般 |
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| Research Field |
生態
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| Research Institution | The University of Tokyo |
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Principal Investigator |
TAKAHASHI Masayuki The University of Tokyo, Graduate School of Arts and Sciences Professor, 大学院・総合文化研究科, 教授 (50111357)
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| Project Period (FY) |
1994 – 1996
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| Keywords | diatoms / non-dominancy / pelagic ocean Ecosystem / water masses / population / distribution / Pacific Ocean / ocean ecosystem |
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| Research Abstract |
During the past 3 years of research, field observations and samplings were carried out covering a large area from 50ﾟN to 65ﾟS in the central and western Pacific Ocean. In the central Pacific, repeated observations in a same period of season were made several times during 3 to 5 years as well as making observations in different seasons in the same area. Large diatom species of >100um in length of cell or colony were particularly concerned because of their easy recognition from natural community. Several to a few 10 species of large diatoms were always found in the entire study area, which demonstrated a wide generous distribution of the large diatoms. No species was distributed throuout the study area but some species occurred in the area of over few 1000km and some others were within a few 100km. The distribution was grouped in 6-8 types. Numerical abundances of each diatom species reached a few % in high latitudes but they were <10^<-4> in the rest of areas. Due to a large biomass of each diatom species, dominancy of biomass became fairly large reaching over 50% at high latitudes, but they were <10^<-2> in the rest of areas. From the present study, ocean areas and seasons where the large diatoms possibly occurred in non-dominance were identified. This has given us a promise to study non-demonancy of species in the ocean.
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