Antarctic microbial biodiversity: the importance of geographical and ecological factors

• Main Authors: Wilmotte, Annick, De Carvalho Maalouf, Pedro, De Wever, Aaike, Obbels, Dagmar, Peeters, Karolien, Verleyen, Elie, Vyverman, Wim, Willems, Anne
• Format: Conference Object
• Language: English
• Published: 2010
• Subjects: Earth and Environmental Sciences; bacteria; Antarctic microbial biodiversity; cyanobacteria; algae; Antarctica; Antarctic; Baas; Antarc*
• Online Access: https://biblio.ugent.be/publication/978400; http://hdl.handle.net/1854/LU-978400

Two contrasting views dominate the vivid debate on microbial biogeography. Proponents of the ubiquity or Baas-Becking hypothesis, which states that ‘everything is everywhere, but the environment selects’, argue that unlimited dispersal prevents isolation and thus allopatric speciation. Opponents of this ‘ubiquity’ concept argue that, similar to larger organisms, dispersal limitation matters in microorganisms and that restricted patterns in geographical distribution and endemism do exist. Antarctic continental ecosystems (including coastal and inland lakes, meltwater streams, cryoconites) are dominated by microbial organisms, which play a crucial role in their functioning. However, little is known about Antarctic microbial biodiversity in comparison with more temperate and/or accessible regions of the world. The BelSPO funded project AMBIO aims to test whether (i) microbial communities are structured by the same factors as those shaping communities of macroorganisms, and (ii) endemism among microbes does exist. To this end, we analysed the microbial biodiversity (cyanobacteria, bacteria, and green algae) in a variety of lacustrine and terrestrial habitats and determined the ‘baseline’ data needed to understand the contribution of various processes that are responsible for the distribution patterns in Antarctic microbial diversity. In all groups studied, we observed a relatively large amount of potentially endemic taxa. A study of the uncultivated diversity of cyanobacteria using Denaturing Gradient Gel Electrophoresis (DGGE) analysis of the SSU rRNA gene revealed that ca 25% of the Operational Taxonomic Units (OTU) is potentially endemic. In bacteria, the cultivated diversity was large and distributed over the major phylogenetic groups with Actinobacteria and Alphaproteobacteria well represented in all samples and with many species and genera new to science. In green algae, microchlorophyte strains isolated from lacustrine habitats were analysed on the basis of SSU rRNA sequences, which revealed a wide ...