Plants are fundamental components of the earth system. Their ability to assimilate atmospheric carbon dioxide, to take up nitrogen and to transpire water shapes the way ecosystems function and controls the provision of ecosystem goods and services that we as people depend on. We investigate the ecophysiological processes in plants that determine the fluxes of water, nitrogen and carbon in natural and agricultural ecosystems. The goals of our research are to understand how plants function in the context of their environment, to reveal the responses of plants and ecosystems to global environmental change, and to establish the ecophysiological and biogeochemical basis for the sustainable use ecosystems.