SUPSI - Institute of Microbiology

Microbial hydrobiology

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The research is centred on the microbial ecology of the anoxygenic phototrophic sulfur bacteria living in the depth, water column (chemocline and monimolimnion) and in the sediments (microbial mats), of the meromictic Lake Cadagno. Especially in the oxic-anoxic transition zone, known as chemocline, the presence of light and hydrogen sulfide (H₂S) promotes the development of an abundant community of anaerobic phototrophic sulfur bacteria. During summer, the concentration of microorganisms in the chemocline can reach values up to 10⁷ cells per milliliter, which turns the water pink, an effect that is visible to the naked eye. Each bacterial population living in this ecological niche is subject to physical, chemical, and biological constraints that imply survival and persistence strategies. Moreover, due to the photosynthetic activity of the anaerobic sulfurous bacteria of the chemocline (i.e. their particular role in the carbon cycle), Lake Cadagno can support much more fish biomass than other alpine lakes, which makes it very popular with fishermen.

The main objectives are the monitoring of the composition and the distribution of key anaerobical microbial species during the year and between the season (up to 20 years), as well as more physiological studies, in the laboratory (in vitro) and in the lake (in situ), increasing the knowledge on two key bio-geochemicals cycles such as sulfur and carbon cycles.

Nicola Storelli

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Biodiversity and functional ecology

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Microscopic saprotrophic fungi of the group aquatic hyphomycetes carry out important processes in the ecosystems of forested streams. They drive the degradation of detritus, especially dry leaves, which are the main basal resource of the food webs in these streams. This field of research studies these processes, the importance of biodiversity, and their sensitivity to environmental change, including pollution and climate change. Projects in this research area use a combination of cultivation of aquatic hyphomycetes, their microscopic, molecular (DNA sequencing) and proteomic characterization (MALDI TOF MS), and quantification of biomarkers for estimates of biomass and enzyme expression.

Andreas Bruder

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Microbial Alpine ecology

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The region of Val Piora offers a singular natural arena for the study and dissemination of ecology in the alpine environment. In fact, thanks to the constant collaboration with the Center for Alpine Biology Foundation (CBA), it is possible to monitor and analyze the ecology of lakes, streams and peatlands using modern instrumentation available in its laboratories.

The CBA's facilities also allow the opportunity to provide practical internships for biology students from leading Swiss universities. Specifically, the EcoMic sector offers a course on microbial hydrobiology on the ecosystems of the meromictic Lake Cadagno and adiacient peat bog (14B641), and a course on stream ecology (14B026).

Synergy with the CBA has also enabled the collection of scientific data during the past 30 years by fostering an accurate monitoanalysis of the phenomenon of climate change (see also CCCT).

Samuele Roman, Nicola Storelli and Andreas Bruder