The composition and new records of micro- and mesophytoplankton near the Vitória-Trindade Seamount Chain

Abstract

Abstract In spite of the length of the Brazilian coastline, studies of marine phytoplankton species in offshore areas have been largely neglected. Regarding phytoplankton species composition, the aim was to assess biodiversity status, species frequency, and the similarities at different sites along the Vitoria-Trindade Seamount Chain. Phytoplankton net samples were analyzed. One hundred and seventy five infrageneric taxa were identified. They represented four phyla, viz., Cyanobacteria, Bacillariophyta, Dinophyta, and Ochrophyta. Dinophyta was the most diverse, and its genus Tripos the largest contributor. This genus also represented more than half of the most common taxa in the sampled area. Thirty-five new infrageneric taxa were recorded, 12 of which are new reports for Brazil. Neritic stations assemblages were markedly different from those of seamounts and deep offshore. The high species diversity, especially among dinoflagellates can be considered typical of tropical oligotrophic waters. The new records demonstrate the gap in knowledge of phytoplankton biodiversity in Brazil.