Viruses cause disease in humans, plants, animals, and even microbes in natural ecosystems. Biologists are only beginning to understand how, through microbial infection and mortality, viruses play a vital role in regulating microbial activities, like the movement of key nutrients in the environment. A keen understanding of nutrient cycling is particularly important in lakes, which are a vital freshwater resource for all Americans. Recent research indicates that viruses may have a bigger and more complex role in nature than previously understood, including serving as a food source for larger microorganisms. The process of consuming viruses as food is called “virovory.” In this project, researchers will examine the importance of viruses as a food source for microbes in lakes, and whether their consumption helps to move nitrogen and phosphorus through aquatic food webs. This project will combine experimental and mathematical approaches to assess the impacts of virovory on nutrient cycling in lakes to determine the degree to which viral nutrients move up through food webs, and to develop a general framework for how these processes function across a variety of lake types. This work will provide potentially transformational insight into the structure and function of nutrient cycles in America’s lakes, with strong potential for applications in biotechnology, and enabling more effective management and helping to improve our understanding of how viruses help maintain important freshwater resources. This study aims to combine manipulative experiments with observational data collection and theoretical modelling to assess the biological impacts of virovorous interactions on both the viral communities of lakes and the cycling of nitrogen and phosphorus within them. Researchers will deploy isotopic tracers to quantify the movement of nitrogen (15N) and phosphorus (32P) from isotopically labelled viral material directly into microzooplankton virovores (ciliate protozoa) and ind