Microbial crossroads: How does virovory influence phosphorus bioavailability in lakes?

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 indirectly into their mesozooplankton predators (copepods). This will provide quantitative measurements of the rate of nutrient flux from the viral fraction into higher trophic levels. These measurements will be compared with microcosm trials measuring the rates of virus removal by virovores, the changes in viral abundance and community composition (using metagenomic approaches), and the growth response of higher trophic levels. The experiments will employ both lab strains and extant communities collected from local lakes and reservoirs, providing a window into the impacts of virovory at both the community and ecosystem scales. Data will be synthesized into a mathematical model to assess in situ rates of virovory in lakes spanning a trophic gradient, providing a tool to determine the impacts of virovory on a variety of natural systems of societal interest. The viral metagenomic data generated in this project will comply with data standards set by the National Center for Biotechnology Information (NCBI) and may facilitate discovery of novel viruses and genetic segments with potential biotechnological applications. Undergraduate and graduate students will be trained in the collection and analysis of metagenomic data, providing a significant and directed focus on education and workforce development for the future of biotechnology. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria. NSF Award ID: 2533822 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Jessica Corman | Institution: University of Nebraska-Lincoln, LINCOLN, NE | Award Amount: $1,085,162 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2533822 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2533822.html