Mountain environments are home to extremophilic terrestrial microalgae that become loaded with pigments to protect them from strong light conditions (notably, high UV irradiance). The red staining of snow and ice surfaces characteristic of such microbial activity at high altitude (known as ‘glacier blood’) is now noticeably more frequent and is evidence that warming is impacting mountain ecology at the most fundamental of levels, with potentially destablising consequences for mountain ecosystems and ice masses . Although algae residing within the surface of high-latitude ice masses is now well-known to play globally significant roles in biogeochemical cycling and ice-albedo feedbacks, the distribution, diversity, and function of algal communities specific to alpine regions has been poorly studied, meaning little is understood regarding their origin and dynamics, means of production, and impact on carbon cycling and glacier melt. This project will couple Earth Observation approaches that will quantify algal community expansion at the Alpine scale with plot- and catchment-level sampling to enable: (a) metagenomic and metaproteomic analyses that will establish microbial community composition, processes and metabolic pathways; and (b) carbon quality and carbon isotope analysis that will quantify carbon fluxes from biological and geological sources. This novel suite of methods aims to provide unique insight into algal community functioning and dynamics and their role in biogeochemical processes that sequester atmospheric CO2.