瀬戸内海から豊後水道にみるガラモ場の変化と水温勾配の関係

摘要

Characteristics of five Sargassum forests were surveyed along the environmental gradients from the western Seto Inland Sea to the Bungo Channel area. Luxuriant forests with many temperate Sargassum species and a kelp(Ecklonia kurome)were observed at the two stations in the Seto Inland Sea(Hiroshima Bay and Iyo-nada sea). Analogous flora and luxuriance was also observed in the northern part(the Sata-Misaki Pen.)and central part(the coast of Uwajima-City)of the Bungo-Channel though increase of coralline algae and sea urchins which symbolizes 'marine desert'(Iso-yake)was also observed. At the southern part(the coast of Ainan-cho), sub-tropical Sargassum and corals appeared and replaced the temperate Sargassum and Ecklonia. Relationship of the shift of Sargassum forests observed and the notable gradient in coastal water temperature along the two sea areas was discussed.