Neolyngbya gen. nov. (Cyanobacteria, Oscillatoriaceae): A new filamentous benthic marine taxon widely distributed along the Brazilian coast.

Brazil has an extensive and environmentally diverse coastline, which favors the occurrence of numerous cyanobacterial morpho- and ecotypes. Nevertheless, this coastline is still poorly studied and its diversity is underestimated. Considering the family Oscillatoriaceae, Lyngbya deserves special attention. It includes many clades which are phylogenetically non-related but morphologically similar. Such clades occur in marine and freshwater environments and are traditionally treated as a single genus. In the current study, we sampled both mediolittoral and estuarine zones along the Brazilian coast. Based on a polyphasic characterization, we described a new genus of marine filamentous cyanobacteria: Neolyngbya. It includes six new species sampled in Brazil, which are described in this study (N. maris-brasilis, N. granulosa, N. irregularis, N. nodulosa, N. arenicola and N. tenuis). Additionally, the characterization included a Neolyngbya sp. from Japan in the clade, but only based on molecular data. All species presented irregular arrangement of thylakoids as described for Oscillatoriaceae. The new genus shares morphological characteristics with species in different clades of the Lyngbya complex. The ultrastructural analyses of Neolyngbya, however, showed numerous gas vesicles, especially in the interthylakoid space; such feature is not observed in benthic Lyngbya species. Neolyngbya formed a well-supported clade (16S rRNA phylogeny), however distantly related to L. aestuarii and L. confervoides, both marine species clusters. The Limnoraphis clade is in a sister relationship to the Neolyngbya clade, however the former occurs in freshwater plankton. Secondary structures of 16S-23S rRNA ITS sequences were congruent with the phylogeny. The polyphasic characterization was helpful to clarify the diversity and ecological aspects of benthic filamentous cyanobacteria and the evolutionary history of the group. This favors a better understanding of inter and infrageneric taxa. The number of novel taxa described in this study emphasizes the importance of conducting additional floristic surveys, mainly in underexplored marine environments, to reveal the real cyanobacterial biodiversity in these areas.

Structure of macroalgal communities on tropical rocky shores inside and outside a marine protected area.

The structure of marine macroalgal communities and morpho-functional groups were investigated in a poorly characterized region on the Tropical Southwestern Atlantic coast, Brazil. The survey was conducted at six rocky shores located on the mainland and on coastal islands distributed inside a marine protected area (MPA) and outside the MPA (near a densely populated area). We hypothesized that tropical rocky shores inside the MPA and islands have higher species richness, diversity, and evenness of marine macroalgae. Results confirmed that species richness, diversity and evenness were significantly higher inside the MPA than in rocky shores outside the MPA. Only species richness was higher on islands than on the mainland. The results suggest that human impacts could lead to a competitive advantage and dominance in the articulated calcareous morphotype, resulting in community differences and lower benthic biodiversity in tropical ecosystems near urbanized sites.

MORPHOLOGICAL AND ULTRASTRUCTURAL FEATURES OF A STRAIN OF BOTRYOCOCCUS TERRIBILIS (TREBOUXIOPHYCEAE) FROM BRAZIL(1).

The genus Botryococcus comprises a group of cosmopolitan species of freshwater colonial green algae, some of which synthesize and accumulate an unusually high level (15-76%) of liquid hydrocarbons. This characteristic suggests the possibility of exploiting species from this group as renewable sources for jet fuel. An oil-rich strain of Botryococcus (Trebouxiophyceae) was isolated from a freshwater pond in the state of Bahia, Brazil, and is presently maintained under standard conditions at the Culture Collection of the Institute of Biology, Federal University of Bahia. The taxonomic classification of the species was based on light microscopy (LM); and TEM and SEM were used to better characterize its features, which have never before been described at this level. The LM characterization included the size of the colonies (35.7-157 µm) and cells (8-10 × 5-9 µm) and their connection in sub-colonies by mucilaginous strands, as well as the presence of mucilaginous processes on the periphery of some of the colonies, with most of the cells included inside the colony. Reproduction occurred through divisions into two to four autospores. These features characterized the species as Botryococcus terribilis Komárek and Marvan. The TEM study showed, in addition to the presence of starch grains, pyrenoids that are penetrated by thick thylakoids. The pyrenoid bodies appear as electron-dense protein inclusions located in the chloroplast and surrounded by a starch sheath. These structures, which contain most if not all of the Ribulose-1,5-bisphosphate carboxylase oxygenase in several algal species that have been studied closely, are newly discovered for this species.