Prokaryotic Metabolic Activity and Community Structure in Antarctic Continental Shelf Sediments

• DOI: 10.1128/aem.69.5.2448-2462.2003
• Publication Date: 2003-05-05T22:24:13Z
• Authors: J. P. Bowman; S. A. McCammon; J. A. E. Gibson; L. Robertson; P. D. Nichols
• Keywords: Psychrophile; Deltaproteobacteria

ABSTRACT The prokaryote community activity and structural characteristics within marine sediment sampled across a continental shelf area located off eastern Antarctica (66°S, 143°E; depth range, 709 to 964 m) were studied. Correlations found between microbial biomass aminopeptidase chitinase rates, which used as proxies for activity. Biomass maximal the 0- 3-cm range declined rapidly with depths below 5 cm. Most-probable-number counting using dilute carbohydrate-containing medium recovered 1.7 3.8% of total bacterial count, mostly facultatively anaerobic psychrophiles cultured. median optimal growth temperature isolates was 15°C. Many identified belonged genera characteristic deep-sea habitats, although most appear be novel species. Phospholipid fatty acid (PLFA) isoprenoid glycerol dialkyl tetraether analyses indicated that samples contained lipid components typical sediments, profiles varying little at same depth; however, significant differences in PLFA 0 1 cm 13 15 cm, reflecting presence different community. Denaturing gradient gel electrophoresis (DGGE) analysis amplified 16S rRNA genes revealed core 4 structure appeared homogenous; principal-component DGGE patterns greater depths, successional shifts evident. Sequencing bands probe hybridization major members delta proteobacteria, putative sulfide oxidizers gamma Flavobacteria , Planctomycetales Archaea . also these groups present similar levels top layer region.