DISSERTATION RESEARCH: Changes in Ectomycorrhizal Fungal Communities Along a Nitrogen Deposition Gradient and Their Consequences for Host Tree Performance

Duke University, Durham NC

Investigators

Abstract

Ectomycorrhizal fungi are abundant, diverse, and ecologically important microorganisms in forest soils throughout the world. Through intimate connections they form with tree roots, they trade essential nutrients obtained from the soil for carbon acquired by trees through photosynthesis. Tree growth in nutrient limited forests can be greatly enhanced in this manner, making the ectomycorrhizal fungal community an important determinant of forest productivity. Increasing amounts of nitrogen produced by the burning of fossil fuels are being deposited in forests of the northeastern U.S. The resulting increases in acidity, aluminum mobility, and N concentration in soil are all factors that can potentially influence ectomycorrhizal fungal communities and their tree hosts. Field research will identify species using DNA-based molecular techniques and measure changes in their abundance and distribution in response to nitrogen pollution. Laboratory experiments will be conducted to examine consequences for tree performance. This will lead to a better understand of the dynamics and consequences of changes in the ectomycorrhizal fungal communities of northeastern forests.