Abstract:Based on the survey of benthic algae in the intertidal zone of Ma’an Archipelago from March to July 2007, the algal species composition, distribution, and temperature feature were studied. The dominant algal species in the study area were preliminarily analyzed by using similarity indices (Sc) and index of relative importance (IRIc). A total of 31 species sampled in sublittoral area were identified, among which, 7 species of 5 genera belonged to Chlorophyta, 8 species of 5 genera belonged to Phaeophyta, and 16 species of 14 genera belonged to Rhodophyta. Topical and selective distribution species influenced by wave and tide were identified in the intertidal zone. Ulva pertusa and Sargassum thunbergii were found in all survey area. Rhodophyta was the dominant species, with the occurring frequency being up to 61.1%, and Chlorophyta showed quite uniformed horizontal distribution. In addition, 81% of sampled species were from low-tide zone, and some were extended from mid-tide zone to low-tide zone. The composition comparability between mid-tide and low-tide species was 0.47, and the convergence effect in mid-tide and low-tide zone was higher than that in high-tide and mid-tide zone. The sublittoral area of Ma’an Archipelago showed obvious vertical zoning character, with temperate species being absolute abundant, and the warm-water species dominant. The marine floral texture of Ma’an Archipelago belongs to warm temperate-subtropical transitional marine flora.