K
Koji Hamasaki
Researcher at University of Tokyo
Publications - 81
Citations - 1486
Koji Hamasaki is an academic researcher from University of Tokyo. The author has contributed to research in topics: Roseobacter & Phytoplankton. The author has an hindex of 21, co-authored 73 publications receiving 1243 citations. Previous affiliations of Koji Hamasaki include Hiroshima University.
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Differing growth responses of major phylogenetic groups of marine bacteria to natural phytoplankton blooms in the western North Pacific Ocean.
Yuya Tada,Akito Taniguchi,Ippei Nagao,Takeshi Miki,Mitsuo Uematsu,Atsushi Tsuda,Koji Hamasaki +6 more
TL;DR: Canonical correspondence analysis showed that organic matter supply was critical for determining bacterial community structures, and the growth potential of each bacterial group as a function of Chl-a concentration showed a bell-shaped distribution, indicating an optimal organic matter concentration to promote growth.
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Variability in Toxicity of the Dinoflagellate Alexandrium Tamarense Isolated from Hiroshima Bay, Western Japan, as a Reflection of Changing Environmental Conditions
TL;DR: The results ecologically imply that the cells become highly toxic in environments with low salinity and high ammonium concentration, and successive cloudy days, and such environmental conditions may lead to increasing risk of shellfish toxification.
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Nitrification and its influence on biogeochemical cycles from the equatorial Pacific to the Arctic Ocean
Takuhei Shiozaki,Minoru Ijichi,Kazuo Isobe,Fuminori Hashihama,Ken-ichi Nakamura,Makoto Ehama,Ken Ichi Hayashizaki,Kazutaka Takahashi,Koji Hamasaki,Ken Furuya +9 more
TL;DR: The relationship between ammonia oxidation and primary production does not simply indicate that ammonia oxidation increased with ammonium supply through decomposition of organic matter produced by primary production but that ammonia oxidizers might also be controlled by micronutrient availability as with primary production.
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Basin scale variability of active diazotrophs and nitrogen fixation in the North Pacific, from the tropics to the subarctic Bering Sea
Takuhei Shiozaki,Takuhei Shiozaki,Deniz Bombar,Lasse Riemann,Fuminori Hashihama,Shigenobu Takeda,Tamaha Yamaguchi,Makoto Ehama,Koji Hamasaki,Ken Furuya +9 more
TL;DR: This study provides evidence for nitrogen fixation in the Bering Sea and suggests a clear contrast in the composition of diazotrophs between the tropical/subtropical gyre and the separate waters in the cold northern regions of the North Pacific.