NSF PRFB FY23: Soil carbon allocation among mycorrhizal species under global change

Edwards, Joseph, Knoxville TN

Investigators

Abstract

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2023, Integrative Research Investigating the Rules of Life Governing Interactions Between Genomes, Environment, and Phenotypes. The fellowship supports research and training of the fellow that will contribute to the area of Rules of Life in innovative ways. Almost all trees have helpful fungi growing on their roots: mycorrhizas. The fungi provide nutrients from soils and, in exchange, the trees feed these fungi carbon (sugars). Some of this carbon ends up trapped in soils. Forest soils store a large amount of atmospheric carbon dioxide, and mycorrhizas can help promote this carbon storage. However, we know little about how plant and fungal species differ in their carbon and nutrient trade economies. These differences could have major impacts on how forests are managed to promote soil carbon storage. This research will investigate how different plants and fungi trade carbon for nutrients and how much of this carbon gets transferred to soils. This information will be used to test whether mycorrhizal species can help better predict future soil carbon storage in forests. In addition, the fellow will communicate these findings through targeted workshops for primary school students at different age levels. The goal of these workshops will be to increase students’ interest in science as a field and future career path. The fellow will investigate species effects on mycorrhizal carbon allocation at spatially hierarchical scales ranging from the laboratory to across the continent. The project will test the hypothesis that mycorrhizal tree and fungal species modulate the exchange rate of carbon and nutrients based on surrounding environmental conditions, with this economy ultimately influencing overall soil carbon storage in forests. Using isotopic labeling, the “carbon cost” of different mycorrhizal fungal species will be measured from cultured fungi. This experiment will be juxtaposed by measuring belowground “carbon supply” from a plant biodiversity experiment, where various tree species have been planted under similar conditions. The relative variation observed among plant and fungal species from these experiments will be compared with soil carbon measurements taken from forests across the United States to assess the degree to which species-level information can effectively predict soil carbon storage. Throughout these experiments, undergraduates from diverse backgrounds will be recruited and trained, and community outreach events will be organized focused on youth organizations. 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.