The Marine Benthic Algae Diversity of Gabon: Case of the Rocky Foreshore of Cap Estérias

Abstract

This study has allowed to classify the marine macroalgae from the intertidal zone on the Atlantic side of Cap Estérias (Gabon). This area has a rich biodiversity but very few studies in the knowledge of benthic macroalgae have been done. The first study on the knowledge of the algae of the Gabonese coast was made in February 1974 by John and Lawson. This article has been revised to transcribe books and our study would aim to update the existing collection . The algae census is spread over a year from August 2020 to August 2021 and is the first detailed study carried out over a year, with regard to this part of the Gabonese coast. This study has allowed to know the specific diversity, to determine the structure of the flora and its spread out over time. The results show a significant algal diversity of thirty f ive (3 5 ) identified species. Three classes of macroalgae were determined and the percentage of species in the class (%EC): Floridaophyceae at 50% EC, Phaeophyceae at 30% EC and Ulvophyceae at 20% EC. The r ed algae are the most common in the area with sixteen (16) species determined against twelve (12) species of brown algae and seven (7) species of green algae. The Phaeophyceae class presents the Dictyotaceae family which is the most diverse with 7 species found. Some species seen appear in the collection of John et al . , but others are new species encountered in Gabon such as Caulerpa sertularioides , Bryopsis plumosa (two Ulvophytes), Padina arborescens which is a Pheophyte and Galaxaura filamentosa , Digenea simplex , Hildenbrandia rubra , Asparagopsis armata and Caulacanthus ustulatus which are Rhodophytes. Some species are permanently present, they are found in all seasons but with significant abundance from July to September.