Journal of the Graduate School of Biosphere Science, Hiroshima University Volume 47
2008-12-20 発行

周防灘における光環境,クロロフィルa 及び濁度の季節・海域変動

Seasonal and spatial variations of optical properties, chlorophyll a and turbidity in Suo-Sound of the western Seto Inland Sea, Japan
Miyashita, Yukihisa
Yukawa, Shota
Tezuka, Naoaki
Hamaguchi, Masami
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abstract
From May to November 2007, we investigated the seasonal and spatial variations of temperature, salinity, optical properties, chlorophyll-α and turbidity in Suo-Sound of the Seto Inland Sea in relation to the Manila clam (Ruditapes philippinarum) production. The bottom turbid layer was found throughout the Suo-Sound, particularly in the western shallow area (bottom depth: about 10 m) which chlorophyll a concentrations were significantly higher than offshore. Generally, the entire water column of western area (bottom depth: less than 20 m) was mostly the euphotic zone. As the fishery grounds of the Manila clam located in the mud flat and the areas less than 5 m water depth, they inhabit in potentially productive area of phytoplankton and benthic microalgae. Also, the highest chlorophyll-α concentrations were observed in October, approximately a few weeks before their autumn spawning period. These results indicate that the marina clam's production is apparently coupled with local environmental factors and seasonal events related to the phytoplankton production.
description
本研究は,広島大学と水産総合センター瀬戸内海区水産研究所との共同研究「瀬戸内海におけるベントスの生産性評価手法の開発」の一環として行われ,「広島大学地域貢献研究」および「水産基盤整備調査委託事業:広域アサリ漁場整備開発のための海況調査」の予算支援を受けたものである。
subject
海底高濁度層
クロロフィルa
時空間変動
光環境
周防灘
アサリ
bottom turbid water
chlorophyll α
seasonal and spatial variations
optical properties
Suo-Sound
Manila clam