Spatial distribution of algae in <i>Ahnfeltia tobuchiensis </i>beds in Amursky Bay (Sea of Japan)
Horizontal and vertical distribution of algae in <i>Ahnfeltia tobuchiensis </i>beds was studied in the area of Mt. Stolovaya in Amursky Bay, Sea of Japan. Thirty-four species of macroalgae (2 species of Chlorophyta, 26 Rhodophyta, and 6 Ochrophyta) were found. Two unattached seaweed <i>Ahnfeltia </i>beds were located opposite Mt. Stolovaya and differed in area, macrophyte stock, number and biomass of attendant species, hydrochemical and light conditions. A monodominant community of <i>Ahnfeltia tobuchiensis</i> was formed in the southern bed, and a bidominant community of <i>Ahnfeltia tobuchiensis</i> + <i>Ahnfeltiopsis flabelliformis </i>occurred in the northern bed. The horizontal distribution of common species of macrophytes in the <i>Ahnfeltia</i> beds at Mt. Stolovaya is apparently conditioned by the amount of photosynthetic active radiation on the surface of the bed. Differences in tolerance of <i>Ahnfeltia</i> and attendant species to low light and light conditions across the bed define the vertical distribution of algae in the bed. <i>Chondrus armatus</i> and <i>Ptilota filicina</i> were chiefly common in the upper layer of the bed. <i>A. tobuchiensis, A. flabelliformis, Chaetomorpha linum,</i> and <i>Coccotylus orientalis</i> occurred across the thickness of the bed.