groundwater; karst aquifers; microbial communities; metagenomics; environmental proteomics
Keiblinger Katharina, Wilhartitz Inés, Schneider Thomas, Roschitzki Bernd, Schmid Emanuel, Eberl Leo, Riedel Kathrin, Zechmeister-Boltenstein Sophie, Comparative evaluation of protein extraction protocols, in
Soil Biology and Biochemistry.
Wilhartitz Inés, Brussaard Corina, Kirschner Alexander, Stadler Hermann, Fischer Ulrike, Wieltschnik Claudia, Farnleitner Andreas, Dynamics of natural prokaryotes, viruses and heterotrophic nanoflagellates inalpine karstic groundwater, in
MicrobiologyOpen.
About 25% of the global population is depending on drinking water from karstic groundwater resources. Consequently, alpine karst research has to provide the basic scientific understanding which enables to take all necessary steps for long term maintaining of the ecological integrity of the respective alpine catchment areas. In contrast to its importance only little knowledge on the ecosystem in karstic groundwater is currently available. Four years ago the applicant and her former working group gave first evidence for the existence of an autochthonous microbial endokarst community (AMEC), whose composition would depend on the prevailing hydro-geological conditions. Furthermore, it was shown that heterotrophic prokaryotic production in aquifer sediment was considerably higher than in the respective water column, confirming the general view that most of the microbial biomass and activity in aquifers is found in the biofilm compartment. The proposed study will be the first comprehensive attempt to establish an ultra-deep sequencing framework of autochthonous karstic aquifer communities in the Central European Region. Arising from earlier results, the hypothesis of a distinct assemblage of prokaryotes, reflecting hydrogeology and lithological composition of an aquifer, has the potential to blaze the way for a plethora of questions, ranging from evolutionary aspects and survival strategies to speculations about endemic subsurface communities.The rapid development in high throughput parallel sequencing approaches and novel tools like total-community divergence measures (such as Unifrac matrix), now allow to verify and expand the AMEC-concept by comparing autochthonous aquifer communities on a regional scale (Central European Region). However, microbial communities present in alpine karst aquifers sometimes have to withstand tremendous changes of environmental parameters such as water levels and nutrient availability. Microbes overcome these challenges often by altering their protein expression profiles but not by immediate genomic rearrangements. Consequently, the mere study of individual genes and their regulation is not sufficient to fully understand microbial adaptation strategies and post-genomic analyses such as proteomics is urgently needed to investigate structure and physiology of complex microbial consortia at a molecular level. These method has contributed substantially to our understanding of individual organisms at the cellular level; however, it has not yet been widely applied in microbial ecology. This study aims at building the base for a robust eco-phylogenetic framework in the karstic subsurface at an unprecedented resolution. It will furthermore use in situ and lab experiments to shed light on interactions between (attached) autochthonous communities and the prevailing hydrogeological conditions in karstic aquifers. The combinations of metagenomics and proteomics will not only identify potential main players of metabolic processes in the saturated karstic subsurface, but also help to understand how communities react to changing conditions. A conceptual model for alpine karst aquifers designed at the end of the project will, for the first time, describe coherences between the occurrence and the possible metabolic potential of autochthonous communities, hitherto unknown. A multi-parametric statistical approach including a wealth of lithological, hydrological, chemical and microbiological background data will put the results in a broader context and establish a basis for pointed research questions in karstic groundwater environments that will reach far beyond the Central European Region.Thereby, this project will not only be groundbreaking for basic research in this relatively young field of environmental microbiology, but it will also be important for sustainable water resource management and provide fundamental data for eco-toxicology and risk assessment in groundwater aquifers