Brazilian Coast: A Significant Gap in the Knowledge of Cyanobacteria and Their Applications

Abstract

Brazil has 10.959 km of coastline which includes three ecoregions based on the biogeographic system, exhibiting a wide range of environments that favor the occurrence of numerous cyanobacterial morpho- and ecotypes. These organisms have a great adaptive capacity, which explains their occupancy in numerous environments and the high diversification of the group. Historically, the cyanobacteria have been classified only based on morphology, which makes their taxonomy quite challenging. There is usually little morphological variation between taxa, which makes it difficult to identify diacritical characteristics between some genera and species, making intergeneric and intraspecific delimitation tough. Thereby, the polyphasic approach based on different tools allows the identification of new taxa and the reassessment of those already established with more reliability, contributing to a better systematic resolution of the world ‘cyanoflora’, a term that we propose herein to describe the diversity of Cyanobacteria into Phycoflora area. However, the use of these tools is still not widely applied to most genera and species, especially those from tropical and subtropical environments, which has limited the real recognition of their biodiversity, as well as the knowledge about the cyanobacteria’s evolutionary history and biogeography. In Brazil, even with the great development of phycological studies, the knowledge about Cyanobacteria from marine benthic environments has not evolved to the same degree. This phylum has been neglected in floristic surveys, presenting only 46 benthic species reported to the long Brazilian coastline, evidencing the still incipient knowledge about the diversity and distribution of this microorganism’s group. Furthermore, biotechnological properties of Brazilian marine cyanobacteria are still almost completely unknown, with only three studies carried out to date, underestimating one of the most diverse groups and with promising potential for the possibility of isolating new biochemically active compounds. The ten new taxa related to the Brazilian coast in the last decade emphasizes the challenge of conducting further floristic surveys in the underexplored marine environments in order to fill an important lacune in the cyanoflora knowledge, as well as their biogeographic distribution and biotechnological potential. Besides, the recognition of the Brazilian cyanoflora makes an important contribution to the understanding of the functioning and monitoring of marine ecosystems and provide data for the construction of future public policies, which is a goal of the United Nations Decade for Ocean Science for Sustainable Development.