Metabolomik und Biodiversität von Schnee- und Eisalgen

Metabolomics and Biodiversity of Snow and Ice Phototrophs

Microalgae growing in snowfields and at glacier surfaces are poly-extremophilic organisms, living in one of the harshest ecosystems existing for eukaryotes. They are adapted to excessive irradiation, low temperature, nutrients or water availability. From late spring onwards, alpine and polar blooms cause striking snow colourations depending on the prevailing pigments, “red snow” being the most common phenomenon. Cryoflora reduces surface albedo and increases melting of its environment which on the other hand enhances rising of the sea level. Moreover, global climate change threatens populations in lower mountain ranges due to lack of snowfall. These organisms are pursued not only for understanding principal cellular survival strategies under harsh conditions, but also for highly abundant, commercially valuable plant metabolites. Algal compounds like polyunsaturated fatty acids, secondary pigments, polyphenolics, antioxidants or polyols play significant roles for cell survival. Still, the biochemical strategies of these extremophiles are poorly understood. Moreover, information about geographic distribution is limited, and the true biodiversity of cryoflora remains cryptic.

The proposed project comprises two main tasks. First, we want to evaluate geographical differences in the biodiversity of Alpine and Arctic snow communities by conducting high-throughput sequencing of total environmental samples, combining multiple genes. This efficient tool to qualitatively and quantitatively ascertain the native snow community structure will be applied for the first time for an alpine-polar comparison. The molecular findings will be correlated with physico-chemical snow parameters. Second, we want to understand how the metabolome of snow and ice algae changes related to stress response.  The metabolome in alpine snow populations will be analysed before and after cells have transformed from protected subsurface green flagellates into exposed red spores in the course of the season and their life cycle. Additionally, we want to reveal the strategies of glacial algae uniquely living at bare alpine and polar ice surfaces. These derived green algae, phylogenetically closer to land plants, remain as actively dividing and vegetative cells throughout the season, not relying on protective spores like most of the snow algae.

All measurements will be conducted with both field material and cultured strains under controlled conditions. A GC-MS-based metabolomics approach will be used to elucidate compound-thriven survival strategies. This includes screening and characterizing of promising ‘anti-stress’-like osmolytes, protective pigments and antioxidants. Such natural compounds are of general interest with respect to human health (e.g. skin protection) or as food ingredients.

The project will be conducted by D. Remias and his master students in collaboration with research partners in Prague, Potsdam and Innsbruck.