Antarctic Microbial Biodiversity: the Importance of Geographical and Ecological factors “AMBIO” (SD/BA/01)

• Main Authors: Wilmotte, Annick, Vyverman, Wim, Willems, Anne, Verleyen, Elie, Peeters, Karolien, Obbels, Dagmar, Souffreau, Caroline, De Carvalho Maalouf, Pedro
• Other Authors: CIP - Centre d'Ingénierie des Protéines - ULiège
• Format: Report
• Language: English
• Published: Belgian Science Policy Office 2012
• Subjects: Antarctica; Biodiversity; Microorganisms; Molecular ecology; biogeography; cyanobacteria; bacteria; microalgae; Life sciences; Environmental sciences & ecology; Microbiology; Aquatic sciences & oceanology; Sciences du vivant; Sciences de l’environnement & écologie; Microbiologie; Sciences aquatiques & océanologie; Antarctic; Baas; The Antarctic; Antarc*
• Online Access: https://orbi.uliege.be/handle/2268/227621; https://orbi.uliege.be/bitstream/2268/227621/1/AMBIO%20FinalReport%20ML.pdf

Microbial organisms dominate most Antarctic ecosystems and play a crucial role in their functioning and primary productivity. Compared with temperate and tropical regions and despite their ecological importance, little is known about Antarctic microbial diversity and its geographical distribution. This is due the lack of systematic sampling and geographical coverage, and the problems associated with species definition, cryptic diversity and cultivability (e.g. Taton et al., 2003). As a result, we largely lack the „baseline‟ data needed to observe possible future changes in microbial diversity and taxonomic composition due to ecosystem change and/or human introductions. Most of the earlier diversity studies were carried out with traditional methods such as isolation of bacterial strains and microscopic identifications of cyanobacteria and protists on the basis of morphological features and „force-fitting‟ of names of temperate taxa on the Antarctic ones. This approach also lacked stability because of the plasticity of the morphology. Molecular tools enabled studies based on the SSU rRNA gene, and have shown a quite different view of the diversity and the existence of not-yet cultivated genotypes. In contrast to phenotypic markers, the genotypic based approaches have a more fine-grained taxonomic resolution and reflect the evolutionary history of the organisms. Molecular-based approaches also have a considerable potential for the study of the geographical distribution of microorganisms. This is important, because it is still unclear whether geographic isolation is present in microorganisms, and hence whether they exhibit a biogeography at all (Martiny et al. 2006). This „ubiquity hypothesis‟ was first formulated by Baas-Becking (1934) and states that „everything is everywhere, but the environment selects‟. It is underlain by the assumption that the vast population sizes of micro-organisms drive ubiquitous dispersal and make local extinction virtually impossible (Finlay et al. 2002). However, various recent studies ...