The ratio between ecosystem respiration and gross primary production determines ecosystem sink capacity. Knowledge of the relationship between carbon assimilation and respiration across time and space could allow the increasingly accurate global gross primary production estimates to be linked with those of net ecosystem production, for which reliable climatic and biological predictors at the global scale are still not available.
Autotrophic and heterotrophic respiration are both related to assimilation, with time delays ranging from seconds to years. Understanding their linkage in time and the controlling environmental drivers is key to understanding biogeochemical processes.
We will give emphasis to the role of arable systems as there are strong indications that they are a source for greenhouse gases, although the processes underlying GHG fluxes from agricultural systems are some of the least well quantified and most uncertain elements in the terrestrial biogeochemical cycle.
The session aims to bring together experimentalists and modellers to share their results on measuring carbon and water use efficiency and the relationship between assimilation and respiration, at local and global scales, as well as their findings on the environmental factors controlling the time shift between carbon assimilation and release processes.