Biogeographical distribution and ecological ranges of benthic cyanobacteria in East Antarctic lakes
Arnaud, T and Grubisic, S and Balthasart, P and Hodgson, DA and Laybourn-Parry, J and Wilmott, A, Biogeographical distribution and ecological ranges of benthic cyanobacteria in East Antarctic lakes, Microbial Ecology, 57, (2) pp. 272-289. ISSN 0095-3628 (2006) [Refereed Article]
For the first time, the cyanobacterial diversity from microbial mats in lakes of
Eastern Antarctica was investigated using microscopic and molecular approaches.
The present study assessed the biogeographical distribution of cyanobacteria in
Antarctica. Five samples were taken from four lakes spanning a range of different
ecological environments in Larsemann Hills, Vestfold Hills and Rauer Islands to
evaluate the influence of lake characteristics on the cyanobacterial diversity.
Seventeen morphospecies and 28 16S rRNA gene-based operational taxonomic
units belonging to the Oscillatoriales, Nostocales and Chroococcales were identified.
The internal transcribed spacer was evaluated to complement the 16S rRNA
gene data and showed similar but more clear-cut tendencies. The molecular
approach suggested that potential Antarctic endemic species, including a previously
undiscovered diversity, are more abundant than has been estimated by
morphological methods. Moreover, operational taxonomic units, also found
outside Antarctica, were more widespread over the continent than potential
endemics. The cyanobacterial diversity of the most saline lakes was found to differ
from the others, and correlations between the sampling depth and the cyanobacterial
communities can also be drawn. Comparison with database sequences
illustrated the ubiquity of several cyanobacterial operational taxonomic units and
their remarkable range of tolerance to harsh environmental conditions.