ICE-COLD: Microbial Diversity in a Lake Ice Ecosystem

The project P14201-BIO had the objective to investigate the colonization and settlement concerning microbes of the winter cover of a high mountain lake. High mountain lakes in the Alps, Pyrenees and probably also other high mountaineous regions are known to have a highly microbial active winter cover which is built up of white ice, clear ice and slush layers. Three main mechanisms for settlement could be observed: The main source for microbes is the lake itself: As soon as snow falls is depressing the ice cover lake water is penetrating the ice, mixing bacteria into the snow. The second known source are the surrounding slopes of the catchment area during ablation phase. Melting streams bring also terrestrial material into the ice cover, speaking of bacteria and nutrients. The third source are atmospheric depositions. Sometimes depositions of saharan dust can be observed at the surface of the lake as well as pollen which are brought up to higher regions from the valleys. All these sources are loaded with various strains of bacteria which differ very much, visible in the attatched dendrograms. The high microbial activity in snow and ice is depicting a completely new understanding of permanent or seasonal ice and snow packs which were normally ssen as sterile. The northern as well as the southern hemispere are covered over long periods (if not over the whole year) with snow and ice which is settled by microbes which are as well capable to degrade various substances and are able to maintain metabolism which can be important for the filtering and degrading characteristics of snow. The findings helped our division to depict an internationally accepted working group on ice and snow ecology which as well led to the nomination of one of the coworkers of the project to represent Austria in the European Polar Board. Furthermore, we are able by invitations by competent nations which have large resources and logistics in polar programmes to participate in comparisons between alpine and polar regions. Our division is supervising various diploma thesis to this topic and are invited to numerous talk which are held at international symposia. The methods used are designed for mostly marine studies and this is one of the few studies where we can establish modern methods in oligotrophic environments as it is the case for high mountain lakes, ice and snow.