Research interests:

I am interested in interactions between climate and terrestrial biogeochemical cycles. Anthropogenic emissions of fossil carbon and and emission of nitrogen from fertilizer and fuel consumption have changed the cycling of carbon and nutrients in forest and grasslands. Future climate change largely depends of how much of the anthropogenic emissions of CO2 remains in the atmosphere. Recent integrations of global models point towards a substantial terrestrial sink of anthropogenic CO2, caused by plants being more productive at elevated CO2 concentrations. This is often referred to as CO2 fertilization. However, currently it is not known whether this mechanism plays out in the future as plant growth might be restricted by the availability of nutrients. In collaboration with the Geophysic Fluid Dynamic Laboratory (GFDL) and Steve Pacala's group, we are developing a dynamic vegetation models that captures the dynamics of nutrients in addition to carbon and hydrological cycles. The model is part of an Earth System Model, that integrates circulation of atmosphere and ocean, as well as terrestrial and oceanic biogeochemical cycles. The model will allow us to quantify nutrient constraints on the CO2-fertilization effect. Moreover the models serves as a tool to address questions such as

- what are the conditions that lead to nitrogen limitation in terrestrial systems?

- what are the consequences of anthropogenic emissions of nitrogen that can readily be absorbed by plants?

- what is the influence of terrestrial nutrient cycling on downstream lakes and estuary system?

- what can we learn from past changes in climate and biogeochemical cycles?

PUBLICATIONS