Does Nitrogen Addition Alter Competition Between Mycorrhizal and Decomposer Fungi?
Nathan Choi Mentor: Kathleen Treseder Mycorrhizal and decomposer fungi differ in their biological roles in the ecosystem. Mycorrhizal fungi form symbiotic relationships with their host plants, exchanging inorganic nutrients for photosynthetically-derived carbon. Decomposer fungi do not form such relationships, but break down compounds to those that can be used by plants and other organisms. To understand how these two different groups of fungi compete against one another under the effects of human pollution, I surveyed fungi that grow in boreal forests that range from high to low nitrogen levels in the soil. I hypothesized that mycorrhizal fungi will not grow as well under nitrogen fertilization, because plants will reduce carbon allocation to mycorrhizal fungi. This response will reduce the ability of mycorrhizal fungi to compete with decomposer fungi under high nitrogen ability. By measuring the signatures of nitrogen-stable isotopes in mushrooms, I could differentiate mycorrhizal fu
