Community compositions of Bacteria and Archaea in the Sea of Okhotsk during summer

Abstract

We investigated spatial variations of the bacterial and archaeal community composition in surface waters of the Sea of Okhotsk during summer of 2006, using denaturing gradient gel electrophoresis (DGGE). We determined phylogenetic assemblages, including Actinobacteria, Bacteroidetes, Cyanobacteria, Alpha-and Gammaproteobacteria, and Marine Group II Euryarchaea, and successfully revealed their spatial distribution patterns. At most stations, Bacteria had higher diversity than Archaea, indicated by the relatively higher Shannon-Weaver indexes and numbers of operational taxonomic units (OTUs). Canonical correspondence analysis (CCA) and redundancy analysis (RDA) demonstrated that the community compositions of bacterial populations in the Sea of Okhotsk were closely associated with total prokaryote abundance, while the spatial distributions of bacterial phylogenetic groups were more related to both the concentration of dissolved organic nitrogen (DON) and the ratio of DON versus dissolved organic carbon concentration (DOC:DON). On the other hand, the spatial variation of the community composition of Archaea had no significant association with environmental parameters.