Interactions between the carbon and nitrogen cycles under elevated CO2
The main topic of my PhD research was on the interactions between the carbon and nitrogen cycles under elevated CO2. We published a review paper synthesizing the ideas I developed during my PhD, describing my own view of the cascading effects of elevated CO2 in a quantitative framework. We review observations from CO2 experiments and suggest potential avenues that most likely explain these dynamics. This framework assumes differentiated effects of CO2 based on the type of mycorrhizal fungi the plant species associate with. The two main types of mycorrhizal fungi (arbuscular mycorrhizae -AM- and ectomycorrhizae -ECM-) have different nutrient economies (transfer different amounts of nutrients to their host plant), which causes differentiated growth and soil responses. Photosynthesis enhancement in response to rising CO2 increases the amount of carbohydrates that the plants can use for different purposes, including trading for nutrients with mycorrhizae, accentuating these dynamics.