SS2.06 Microbial Diversity in Time and Space
Date: Tuesday, June 11, 2002
Time: 9:30:00 AM
Location: Lecture Theatre
 
RappeMS, Dept. of Microbiology, Oregon State Univ., Corvallis, Oregon, USA, Michael.Rappe@orst.edu
Giovannoni, S, J, Dept. of Microbiology, Oregon State Univ., Corvallis, Oregon, USA, steve.giovannoni@orst.edu
 
THE MAJOR MARINE BACTERIOPLANKTON rRNA GROUPS: DIVERSITY, DISTRIBUTION, DYNAMICS, AND CULTIVATION
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Cultivation -independent characterization of marine bacterioplankton communities by SSU rRNA gene cloning and sequencing spans over thirteen years, forty samples, and more than one thousand clones. Most rRNA genes from this combined data set do not correspond to cultured species. Instead, ca. 80% of marine bacterial clones fall among nine phylogenetic groups, and nearly all archaeal clones fall within two groups. Most of these groups exhibit cosmopolitan distributions. Coastal and open ocean bacterioplankton communities contain many of the same phylotypes; however, a variety of bacterioplankton, including beta Proteobacteria, appear solely in coastal environments. Until recently, only two of the eleven major groups contained cultivated representatives. Recently we cultivated members of a third group, the SAR11 cluster, by extinction culture. In the Western Sargasso Sea, we have employed rRNA probing methods to track the spatial and temporal distribution of bacterioplankton community members. Vertical stratification of bacterioplankton populations is typical in the Sargasso Sea surface layer, and some of the major bacterioplankton groups exhibit seasonal oscillations in abundance.