東京湾の3干潟における底生珪藻の分布

摘要

To investigate environmental factors affecting the species composition of benthic diatoms, surveys of the surface sediment and overlying water were conducted at three intertidal flats in Tokyo Bay: Marine Park, Edogawa, and Kasai. Species were identified by light microscopy and classified into two growth form types: gliding and adhesive. In total, 67 taxa were identified. Seasonal variations of dominant growth forms differed between the intertidal flats; dominant species were Catenula adhaerens, Cocconeis sp. 1, and Fallacia sp. (adhesive type) on the Marine Park; Fallacia forcipata (gliding type) on the Edogawa; and Amphora copulata, A. laevissima (adhesive type), Gyrosigma fasciola, and Navicula cf. mollis (gliding type) on the Kasai. Cluster analysis based on the similarity of major species differentiated the three sites, while the Kasai cluster was further subdivided by season. Redundancy analysis revealed that (1) the correlative environmental factors differed between growth forms and only the gliding type was positively related to mud content, and (2) diatom species composition on the Kasai was related to salinity. These results indicate that tide and wave disturbance and also salinity strongly affect benthic diatom species composition in Tokyo Bay.%底生微細藻類は干潟における主要な一次生産者であり（MacIntyre et al.,1996；Underwood and Kromkamp，1999）、浅海域の栄養塩のフローや溶存酸素濃度の変化に関わっていることや（Bartoli et al.,2003；Tyler et al.,2003）、細胞外多糖類を分泌して底質を安定化させること（Paterson,1989；Stal,2003；Lundkvist et al.,2007）などから近年その重要性が認識されている。