Contribution of benthic microalgae to the whole water algal biomass and primary production in Suo Nada, the Seto Inland Sea, Japan

瀬戸内海周防灘における水柱全体の藻類バイオマスと一次生産に対する底生微細藻の寄与

Sarker Md. Jahangir

Yamamoto Tamiji

Hashimoto Toshiya

Jouranal of Ocennography

周防灘全域において, 2001年度に行った季節ごとの観測結果から, 微細藻のバイオマスと一次生産について, 浮遊微細藻および底生微細藻の比較を行った。光補償深度と水深の比較から, 周防灘南西部が底生微細藻が潜在的に生息可能な海域であるとみなすことができた。海底には上層水柱から沈降してきた浮遊微細藻が多いが, 南西部海域ではバイオマス・一次生産ともに底生微細藻のそれが大きいことが分かった。しかしながら, 南西部海域で水柱全体に占める底生微細藻のバイオマスの割合は, 冬に7%, 夏に2%であった。また, 底生微細藻の一次生産量は4.0-74.0 mg C m-2 d-1 の範囲であり, これは水柱全体の2-12%に相当した。底生微細藻の役割は, それ以外に, 底泥から水柱への栄養塩フラックスを減少させたり, 底泥表層を酸化的に保ったり, 動物ベントスの餌となったりするので, これらについても考察を加えた。

Biomass and primary productivity of benthic microalgae (BMA) and planktonic algae in Suo Nada, the western part of the Seto Inland Sea, Japan were compared in terms of unit area with regard to their seasonal and spatial distribution in 2002. Judging from light compensation depth and water depth, the southwestern part of Suo Nada was considered to be a potential habitat for BMA. Whereas the contribution of sedimented planktonic algae was high in biomass at the sediment surface, BMA was obviously significant both in biomass and primary production in the shallow southwestern part. However, the contribution of BMA to the total biomass in the entire water column was 7% in winter and 2% in summer. The primary production of BMA varied between 4.0 and 74.0 mg C m(-2) d(-1) in the southwestern part, accounting for 2-12% of the whole water column primary production. The ecological roles of BMA in the Suo Nada ecosystem are discussed, such as reduction of benthic nutrient flux, oxidation of surface sediments and feed for higher animals.

Benthic microalgae

planktonic algae

biomass

primary production

Suo Nada

水産業 [ 660 ]

英語

Springer

Copyright (c) 2009 Springer-Verlag. "The original publication is available at www.springerlink.com"

[ISSN] 0916-8370

[DOI] 10.1007/s10872-009-0029-5

[NCID] AA10833529

[DOI] http://dx.doi.org/10.1007/s10872-009-0029-5