Despite their pivotal role as primary producers, there is little information as to the diversity and physiology of cyanobacteria in the meltwater ecosystems of polar regions. Thirty cyanobacterial mats from Adelaide Island, Antarctica were investigated using 16S rRNA gene pyrosequencing and automated ribosomal intergenic spacer analysis, and screened for cyanobacterial toxins using molecular and chemical approaches. A total of 274 operational taxonomic units (OTUs) were detected. The richness ranged between 8 and 33 cyanobacterial OTUs per sample, reflecting a high mat diversity. Leptolyngbya and Phormidium (c. 55% and 37% of the OTUs per mat) were dominant. Cyanobacterial community composition was similar between mats, particularly those obtained from closely adjacent locations. The cyanotoxin microcystin was detected in 26 of 27 mats (10-300 ng g(-1) organic mass), while cylindrospermopsin, detected for the first time in Antarctica, was present in 21 of 30 mats (2-156 ng g(-1) organic mass). The latter was confirmed via liquid chromatography-mass spectrometry and by the presence of the cyrAB and cyrJ genes. This study demonstrates the usefulness of pyrosequencing for characterizing diverse cyanobacterial communities, and confirms that cyanobacteria from extreme environments produce a similar range of cyanotoxins as their temperate counterparts.
We acknowledge the Carl Zeiss Stiftung and the Excellence Initiative of the University of Konstanz, Germany, for funding the PhD project of JK. JK is now
a BeIPD Marie-Curie COFUND research fellow at the University of Liège. We are grateful to UK Natural Environment Research Council (NERC) and British Antarctic Survey (BAS) for funding the AFI-CGS-70 grant and the field trip to Antarctica, as well as all BAS staff for their logistic and scientific support, especially the team of Rothera Research Station. FCK gratefully acknowledges further funding support from NERC (Oceans 2025 WP 4.5 and NF-3 core funding to the Culture Collection of Algae and Protozoa). We thank the Antarctic Science Bursary for funding the 454® sequencing. This research was supported by a Marie Curie International Research Staff Exchange Scheme Fellowship within the 7th European Community Framework Programme (DRD and SAW). For technical support and stimulating discussion, we are very grateful to Dr David Schleheck, Dr Dominik Martin-Creuzburg, Lisa Zimmermann, Julia Stifel, Martina Sattler and Dr Anne Jungblut. FH is supported by the Research Foundation – Flanders (FWO). We would also like to thank the reviewers for their valuable comments on the manuscript.
- automated ribosomal intergenic spacer analysis
- liquid chromatography-mass spectrometry
- fresh-water ecosystems