Marine Bacterioplankton Diversity and Community Composition in an Antarctic Coastal Environment

• Published in: Microbial ecology Vol. 63; no. 1; pp. 210 - 223
• Main Authors: Giudice, Angelina Lo, Caruso, Consolazione, Mangano, Santina, Bruni, Vivia, De Domenico, Maria, Michaud, Luigi
• Format: Journal Article
• Language: English
• Published: New York Springer Science + Business Media 01-01-2012; Springer-Verlag; Springer; Springer Nature B.V
• Subjects: Actinobacteria; Antarctic Regions; Aquatic Organisms; Bacteria; Bacteria - genetics; Bacteria - growth & development; Bacteria - isolation & purification; Bacterioplankton; Bacteroidetes; Base Sequence; Biodiversity; Biological and medical sciences; Biomedical and Life Sciences; Carbon sources; Chemical analysis; Coastal environments; Community composition; Cytophaga; DNA, Bacterial - genetics; DNA, Ribosomal - genetics; Ecology; Ecosystem; Flavobacter; Fundamental and applied biological sciences. Psychology; Gammaproteobacteria; Gelidibacter; Geoecology/Natural Processes; In Situ Hybridization, Fluorescence; Life Sciences; Marine environment; Microbial Consortia; Microbial Ecology; Microbiology; MICROBIOLOGY OF AQUATIC SYSTEMS; Molecular Sequence Data; Nature Conservation; Nitrogen cycle; Phylogenetics; Plankton - genetics; Plankton - growth & development; Plankton - isolation & purification; Polaribacter; Pseudoalteromonas; Ribosomal DNA; RNA, Ribosomal, 16S - genetics; Salt tolerance; Sea ice; Sea water; Seas; Seawater; Seawater - microbiology; Sequence Analysis, DNA; Water analysis; Water column; Water Quality/Water Pollution; Antarctica; Antarctic Regions; PS, Antarctica, Ross Dependency, Terra Nova Bay; PS, Ross Sea; Alphaproteobacteria; Actinobacteria; Bacterioplankton Community; Bacteroidetes; Gammaproteobacteria; Marine environment; Community structure; Bacterioplankton; Plankton; Ecology; Coastal environment; Polar region; Climatic zone
• ISSN: 0095-3628; 1432-184X
• DOI: 10.1007/s00248-011-9904-x

The bacterial community inhabiting the water column at Terra Nova Bay (Ross Sea, Antarctica) was examined by the fluorescent in situ hybridization (FISH) technique and the genotypic and phenotypic characterization of 606 bacterial isolates. Overall, the FISH analysis revealed a bacterioplankton composition that was typical of Antarctic marine environments with the Cytophaga/Flavobacter (CF) group of Bacteroidetes that was equally dominant with the Actinobacteria and Gammaproteobacteria. As sampling was performed during the decay of sea-ice, it is plausible to assume the origin of Bacteroidetes from the sea-ice compartment where they probably thrive in high concentration of DOM which is efficiently remineralized to inorganic nutrients. This finding was supported by the isolation of Gelidibacter, Polaribacter, and Psychroflexus members (generally well represented in Antarctic sea-ice) which showed the ability to hydrolyze macromolecules, probably through the production of extracellular enzymes. A consistently pronounced abundance of the Gammaproteobacteria (67.8%) was also detected within the cultivable fraction. Altogether, the genera Psychromonas and Pseudoalteromonas accounted for 65.4% of total isolates and were ubiquitous, thus suggesting that they may play a key role within the analyzed bacterioplankton community. In particular, Pseudoalteromonas isolates possessed nitrate reducíase and were able to hydrolyze substrates for protease, esterase, and β-galactosidase, thus indicating their involvement in the carbon and nitrogen cycling. Finally, the obtained results highlight the ability of the Actinobacteria to survive and proliferate in the Terra Nova Bay seawater as they generally showed a wide range of salt tolerance and appeared to be particularly competitive with strictly marine bacteria by better utilizing supplied carbon sources.