Abstract

The spatial distribution and diversity within bacterioplankton assemblages in four coastal sites along the southern points of the Atlantic Ocean were examined using the Illumina high-throughput that targets 16S rRNA genes to examine indigenous bacterial assemblages in the littoral zones along the coast of the ocean. Results of the study showed very similar bacterial representation between the coastal sites with majority of the sequences affiliated with members of the Proteobacteria (52 to 59%), Bacteriodetes (21 to 31%) followed by Actinobacteria (3 to 9.5%) and Planctomycetes (2.1 to 4.5%).  The bacterioplankton assemblages at each site examined were quite diverse, with members of the Gammaproteobacteria found as the most abundant bacterial class among the four sites.  However, clear differences were observed among the sites at the order level, with the Chromatiales the more dominant in the eastern coastal (CPTI) sites, while clades belonging to the Flavobacteriales and Rhodobacterales were more prevalent in the two western (CPTA) coastal sites.  While the results of unweighted pair group method with arithmethic (UPGMA) clustering and principle coordinate (PCoA) revealed two spatially separate clusters among sites, canonical correspondence (CCA) analysis indicated that environmental variables such as temperature, pH and conductivity were probably the major influencers of bacterial occurrences at the coastal sites.

Key words: Bacterioplankton assemblages, ocean, 16S rRNA gene sequencing.