瀬戸内海備後灘における海洋基礎生産に関する研究I : 基礎生産および海況について

On primary production in Bingo-Nada of Seto Inland Sea I : Primary production and hydrographic condition

Endo Takuo

広島大学水畜産学部紀要

Journal of the Faculty of Fisheries and Animal Husbandry, Hiroshima University

In order to know the magnitude of primary production in the Bingo-nada area in the central part of the Seto Inland Sea, the photosynthesis (by 14 C method) and the chlorophyll contents were measured at the two stations, BG-1 and -2. The measurements were carried out once a month from September 1962 to September 1963.

Seasonal changes of the hydrographic conditions are shown in Text-figs. 2-6. Secchi disc depth is small in this area, especially at BG-2.

The results of primary production measurements are shown in Text-figs. 7-10. The primary production is within the rangeof 0.03-l. 79 g/m2/day as Carbon; it is relatively great in May, June, August and September, and relatively small in November, December and February.

The ratio of the photosynthesis determined by the tank experiment to chlorophyll a content is smaller than 6 in most of the cases. The ratio tends to increase as water temperature rises; at the same temperature, however, it sometimes varies remarkably among stations or layers, suggesting that this ratio is affected not only by temperature but also by some other factor(s) (Text-fig. II).

No correlation is found between the chlorophyll a content (in the water column from Om to the Secchi disc depth) and the Secchi disc depth (Text-fig. 12).

Fishing industry. Fisheries [ 660 ]

jpn

広島大学水畜産学部

[ISSN] 0440-8756

[NCID] AN00213563