Microbial communities are the main responsible of biogeochemical cycles (cycling of substances) in aquatic systems. These cycles can be strongly affected by human activities and thus by climate change with consequences on the release of greenhouses gases, such as CO2 and CH4. Viruses are a key and yet neglected component of these microbial communities. They kill and modulate the abundances of bacteria, archaea, protists and fungi, which are a dominant part of the biomass in aquatic systems. Through host lysis, they therefore have an impact on bacterial respiration, CO2 emission and nutrients cycles. Further, viruses are responsible for microbial evolution by selecting microbes resistant to infection and by genetic material transfer. Freshwater ecosystems represent only 0.01% of water on Earth and yet they are of great ecological importance supporting 6% of global biodiversity and offering a wide range of ecological services (e.g. irrigation, fishing, pasturing, tourisms, outdoor activities and hydroelectricity production). Freshwaters are among the most threatened ecosystems globally
Viral communities in freshwaters are globally under-studied, and virtually no information exists on Alpine lakes.
metaVir-Alp aimed to characterise the genetic diversity, structure and function of viral and bacterial communities in freshwater systems along an altitudinal gradient combining metagenomics, microbiology, and advanced computation. As model system, I used the threated Alpine lakes. Specifically, we focused on lake sediments that are hotspots of carbon cycling due to the large deposition of terrestrially derived carbon and the greenhouse gases outgassing (by microbial mineralization).
During the two years, three intensive and challenging sampling sessions (Pre-sampling 2017, Summer 2017 and Winter 2018) were carried out collecting water and sediment from two sites in 4 Alpine lakes along an altitudinal gradients (from 680m to 2000m). We compiled a comprehensive dataset with physico-chemicals data for each sampling point in each lake (D1). We produced a DNA bank of 34 microbial and 34 viral communities (D2), which is and will be used to perform high-throughput sequencing in order to have a comprehensive genetic characterisation of freshwater microbial and viral communities. This resource is a valuable information that will give an insight of the viral genetic diversity and function in freshwater. Further, the successful secondment at the Fondazione Edmund Mach generated also a productive collaboration on a side project on Cyanobacteria. Equally important, this fellowship allowed me to resume successful my career after two years of maternity leave, by completing a novel research project and acquiring key skills that permitted my career to go further.
