(DFG, 2004-2008, Special Priority Program Research in Antarctica and adjacent polar regions)
This project aims to investigate the distribution, diversity and abundance of a recently defined narrow Roseobacter cluster, the Roseobacter Clade Affiliated (RCA) cluster, in comparison to the Roseobacter clade and the SAR11 clade of alpha-subclass Proteobacteria in the Southern Ocean by real time PCR. This will be achieved by target group-specific primers for amplifying fragments of the 16S rRNA gene. A previous study of the applicants showed that the RCA cluster constitutes around 20% of the domaine Bacteria in the Southern Ocean thus indicating that it is an important structural component of the bacterioplankton. The diversity within the Roseobacter and SAR11 clades will be analyzed by DGGE and clade-specific primers and sequencing of prominent DGGE bands. The investigation is based on samples which were collected during cruise ANT XVI/3 with RV Polarstern from March to May 1999, spanning regions from north of the Subtropical Front to the Antarctic Coastal Current and including the Subantarctic region, the polar frontal region, the Antarctic Circumpolar Current and the eastern Weddell Sea. The results will lead to a better understanding of the occurrence and dynamics of the major players of the bacterioplankton in the Southern Ocean.
Individuals working in the project:
Helge-Ansgar Giebel, Thorsten Brinkhoff, Meinhard Simon.
Giebel HA, Kalhoefer D, Lemke A, Thole S, Gahl-Janssen R, Simon M, Brinkhoff T (2011) Distribution of Roseobacter RCA and SAR11 lineages in the North Sea and characteristics of an abundant RCA isolate, ISME J 5: 8-19 (doi:10.1038/ismej.2010.87).
Giebel HA, Brinkhoff T, Zwisler W, Selje N, Simon M (2009) Distribution of Roseobacter RCA and SAR11 lineages and distinct bacterial communities from the subtropics to the Southern Ocean. Environ. Microbiol. 11/8:2164-2178 (doi:10.1111/j.1462-2920.2009.01942.x).