<論文>1993年夏期の北太平洋亜寒帯表層域における珪藻の東西分布

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Thirty six surface water samples were collected on board T/S Oshoro-Maru, Hokkaido University, during 13 July-19 August 1993 along an east-west transect from Seattle, USA to Hakodate, Japan. Diatom standing stock ranged from 1.5×10^4 cells/l to 3 X 10^5 cells/l depending on the sampled localities. The high standing stocks occurred between 158° and 165°E where the Western Subarctic Gyre exists. These high values may stem from upwelling conditions in the gyre postulated by Otani (1988). Pennate diatoms dominated numerically (>70% of total diatoms) throughout the transect except for a coastal station off Hokkaido. Among the pennates Nitzschia pseudonana group with, pico-nanoplankton sized taxa, contributed between 72 and 98%. Quantitative distributions of Neodenticula seminae and Nitzschia pseudonana group are inversely correlated. Centric diatoms were mainly composed of two genera : Thalassiosira and Chaetoceros. Distributions of Chaetoceros atlanticum, Chaetoceros concavicorne, Thalassiosira oestrupii and Thalassiosira lineata did not overlap significantly in their standing stock. It appears that each of these relatively numerous centric taxa prefers particular environmental conditions persisting in each of the water masses.
北海道東海大学の論文
1995-03-25