SUBTIDAL BENTHIC MARINE ALGAE OF THE TODOS OS SANTOS BAY, BAHIA STATE, BRAZIL

Abstract

The Todos os Santos bay is a Brazilian coastal marine area that was appointed as top priority for biological conservation. However, there are still too few studies about the local composition of marine communities. The aim of the present investigation was to survey the diversity of marine algae in the sub-tidal zone around the reefs of the Todos os Santos bay. Samples from seven different sites in the bay were obtained by scuba diving through qualitative and quantitative methods, being the collections repeated in rainy and dry seasons. One-hundred and forty-two taxa were found: 31 Chorophyta, 27 Ochrophyta, 83 Rhodophyta, and one Macrophyte. Higher diversity and evenness indices were found during the dry season. Sargassum spp., Dictyopteris delicatula, and Halimeda opuntia were the most abundant macroalgae in the bay. Greatest number of species and most abundant samples were obtained in the oceanic region of the bay, while fewer species and less abundant samples were obtained in areas that are more exposed to the effects of human disturbance. The composition of the flora and abundance of macroalgae in each area of Todos os Santos bay seem to be determined by the quality of local seawater (i.e. degree of eutrophication).