Presentation of the project
AMBIO will determine the microbial diversity,
community composition and taxonomic turnover in permanently and seasonally wet
habitats (lakes, cryoconites and seepages) across Antarctica, and assess
the relative importance of ecological versus historical factors in explaining
the geographical distribution of particular taxa and communities. To
this end, we will study regions at a circum-Antarctic level and along a
latitudinal gradient ranging from high-latitude continental sites in East and
West Antarctica (including the site of the future Belgian Base near the
Utsteinen nunatak), to the Sub-Antarctic islands.
The first two years will be devoted to a systematic inventory of the
diversity and community composition as well as to the establishment of culture
collections of focal groups. Focus will be on Proteobacteria,
Bacteroidetes, Cyanobacteria, Chlorophyta and Bacillariophyta, all known to be
well-represented in Antarctic microbial communities. A mid-term assessment will
identify regions and taxa particularly important to test hypotheses
about the driving factors behind Antarctic microbial diversity and its
evolution. These will be the focus of the two following years of the project.
Importantly, the results will help identifying Antarctic Special Protected
Areas (ASPA).
This proposal results from the successful partnership developed within
the framework of the EU-project MICROMAT
and the Belgian Science Policy projects LAQUAN and HOLANT,
which so far resulted in more than 20 joint publications. During these
projects, the Belgian teams have developed novel expertise in the study of
actual and past microbial communities in lake sediments with molecular tools
and inference models for water balance and productivity changes (e.g. Verleyen
et al. 2003; 2004c; Taton et al. 2003; 2005; Schmoker et al. in prep., Verleyen
et al. subm.). In addition, we have recently established collaborative links
with Japanese researchers (Prof. Dr. T. Naganuma and Dr. S. Imura) in order to
extend the recently developed datasets within the JARE REGAL project on the succession and evolution of lacustrine biota
in the lakes in Syowa Oasis. The project is further firmly integrated within
international initiatives including the IPY proposal n55 MERGE (Microbiological and Ecological
Responses to Global Environmental Changes in Polar Regions) where it will
contribute to the Theme 1 Diversity and biogeography.
The experience acquired during preceding projects will be used to improve the
methodologies for the isolation of strains and characterisation of the
phenotypic and genotypic diversity of samples and strains. There will be
interactions with MERGE concerning the harmonised protocols to be used by all
partners during IPY. The project will further contribute documented new
microbial isolates to the BCCM culture collections of bacteria, polar
cyanobacteria and green algae and diatoms and will itself benefit from expertise gained in the
culture collection projects.
The specific aims of the current proposal are:
- to expand the existing database
of rRNA operon sequences of bacteria, cyanobacteria and microalgae with
new samples from Maritime and Continental Antarctica, as well as from
Sub-Antarctica based upon isolates, clone libraries and DGGE of
environmental DNA,
- to enlarge the existing
collections of Antarctic bacteria (particularly Proteobacteria and
Bacteroidetes), Cyanobacteria and diatoms, with new documented isolates,
- to study the microbial
diversity in wet terrestrial habitats in the three biogeographic regions
of the continent: Sub-Antarctica, Maritime and East Antarctica,
- to study the community turnover
within each taxonomic group between different habitats (e.g., lakes,
cryoconites and seepages) and among comparable habitats along ecological
and geographical gradients to analyse the congruence and disparity in
patterns of diversity and taxonomic turnover observed for different taxa,
- to select in each of the groups
(Proteobacteria, Bacteroidetes, Cyanobacteria, green algae and diatoms),
particular taxa (genus to infraspecific level, phylotype) that display
striking distribution patterns (e.g. potentially endemic or cosmopolitan
with or without apparent environmental specialisations), for further
detailed study of these patterns. The presence of the selected taxa will
be monitored with more specific and more sensitive genotypic methods in an
enlarged set of samples so as to allow a more precise analysis and
facilitate interpretation in relation to other ecological and historic
factors,
- to identify regions of unique
microbial diversity that deserve to be protected.
