Mangrove Macroalgal Communities

The present chapter outlined the current state of knowledge on the taxonomy, ecology, cultivation, and chemical diversity of Brazilian mangrove macroalgae. Brazilian mangrove macroalgal community presents low species diversity estimated in 22 species (15 Rhodophyta and 7 Chlorophyta), dominated by a few genera as Bostrychia, Caloglossa, and Catenella, whose assemblage is known as “Bostrychietum.” Among Chlorophyta, species of Gayralia, Boodleopsis, Cladophoropsis, Pseudorhizoclonium, and Rhizoclonium are found on different substrates. Taxonomical studies based on molecular markers in combination with morphological and developmental analyses elucidated the occurrence of cryptic species in Caloglossa and Gayralia. However, further studies are required to elucidate the taxonomy of small filamentous green algae belonging to Bryopsidales and Cladophorales orders. Ecological studies on Brazilian mangroves reported that Bostrychia radicans and B. calliptera are the predominant species in coverage and biomass. Spatial variations on species composition, distribution, and biomass are related to salinity gradients, flooding frequency, and light, while temporal variation is related to temperature, tidal levels, and tolerance of each species to withstand emersion. The strategies of macroalgae to survive in mangroves could explain the large number of compounds biosynthesized and associated endophytic fungi with potential as bioactive compounds. Studies on chemical diversity are focused on Bostrychia and Gayralia from the southern and southeastern regions, and need to be extended to mangroves from other regions of Brazil as well as to other taxonomic groups.