Summary

• Main Authors: Guus Roeselers, Tracy B. Norris, Richard W. Castenholz, Søren Rysgaard, Ronnie N. Glud, Michael Kühl, Gerard Muyzer
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Arctic; Greenland
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.520.2798; http://www.mbl.ku.dk/mkuhl/pages/pdf/roeselers_et_al_2006pre.pdf

We investigated the genotypic diversity of oxygenic and anoxygenic phototrophic microorganisms in microbial mat samples collected from three hot spring localities on the east coast of Greenland. These hot springs harbour unique Arctic microbial ecosystems that have never been studied in detail before. Specific oligonucleotide primers for cyano-bacteria, purple sulfur bacteria, green sulfur bacteria and Choroflexus/Roseiflexus-like green non-sulfur bacteria were used for the selective amplification of 16S rRNA gene fragments. Amplification products were separated by denaturing gradient gel electro-phoresis (DGGE) and sequenced. In addition, several cyanobacteria were isolated from the mat samples, and classified morphologically and by 16S rRNA-based methods. The cyanobacterial 16S rRNA sequences obtained from DGGE represented a diverse, polyphyletic collection of cyanobacteria. The microbial mat communities were dominated by heterocystous and non-heterocystous filamentous cyanobacteria. Our results indicate that the cyano-bacterial community composition in the samples were different for each sampling site. Different layers of the same heterogeneous mat often contained dis-tinct and different communities of cyanobacteria. We observed a relationship between the cyanobacterial community composition and the in situ temperatures of different mat parts. The Greenland mats exhibited a low diversity of anoxygenic phototrophs as compared with other hot spring mats which is possibly related to the photochemical conditions within the mats resulting from the Arctic light regime.