Career: impact of elemental limitation on the evolution and composition of bacteria

The National Science Foundation Division of Environmental Biology awarded Loyola University of Chicago $775,664 on June 1, 2026, under the Biological Sciences program (CFDA 47.074) to investigate how bacteria evolve in response to elemental limitation.

The research will examine bacterial evolution under controlled laboratory conditions with varying ratios of carbon, nitrogen, and phosphorus. Researchers will measure elemental composition, genetic changes, and fitness in evolved bacteria to determine whether selection under elemental limitation favors a nutrient-sparing response in which bacteria incorporate less of the limiting element. The project will also test whether evolutionary outcomes differ under selection for faster growth rate versus increased yield, clarifying how differing environmental pressures shape response to elemental scarcity. The work addresses how human alteration of elemental availability through fertilizer application may drive bacterial evolution across natural habitats.

The project integrates education and research by providing community college students the opportunity to conduct an evolution experiment in introductory biology laboratory courses and contribute as undergraduate researchers to the broader investigation.

Work is performed in Chicago, Illinois, with a period of performance from June 1, 2026, through May 31, 2031. This is a Project Grant assistance type.

Abstract

All organisms consist of a mixture of elements in differing ratios. Elements such as carbon, nitrogen, and phosphorus are needed to make the nucleic acids, proteins and other molecules that are the building blocks of cells. However, the availability of these elements in organisms? Environments often differs from the proportions needed by organisms. As a result, the availability of the scarcest element can limit growth. This project will explore how bacteria evolve in response to the scarcity of different elements. Bacteria will evolve under controlled laboratory conditions with varying ratios of carbon, nitrogen, and phosphorus. The researchers will measure elemental composition, genetic changes, and fitness of the evolved bacteria. Human activity has altered elemental availability across a variety of habitats, including addition of nitrogen and phosphorus as fertilizer. The research in this project will help lay the foundation for understanding how organisms may evolve in response to changes in elemental availability. This project will also provide research experiences for community college students who will conduct an evolution experiment as part of their introductory biology laboratory course and then have the opportunity to contribute to the project as undergraduate researchers. This project will address how the elemental composition of bacteria evolves in response to elemental limitation. The researchers will test whether selection under elemental limitation favors a nutrient sparing response in which bacteria evolve to incorporate less of the limiting element in their cells. The evolutionary response to elemental limitation may also depend on other aspects of the environment. This research will test the role of differing selection pressures by comparing the outcome of evolution under selection for faster growth rate and evolution under selection for increased yield. Response to limitation may also depend on the starting characteristics of the organisms. To explore this, the researchers will also test the role of genetic background on the evolutionary response to limitation. 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.- subawards are not planned for this award.