Monitoring of CO2 exchange and carbon pools in vegetation and soil

Global efforts to reduce the emissions require proper monitoring and understanding of the carbon inputs and outputs by the terrestrial ecosystems i.e. vegetation and soil. Photosynthesis and net primary productivity can be used as indicators of carbon exchange and their estimate can be made through traditional approaches as well as other approaches e.g. mechanistic photosynthesis models and the light use efficiency with satellite data. Advancements have taken place for monitoring the CO2 exchange at different scales viz. leaf, stand-, landscape levels, vertical carbon column- and satellite observations. There are methods to partition the fluxes based on discrimination of isotopes of carbon by terrestrial ecosystem processes. The soil is a vast reservoir of carbon and has a great potential for atmospheric carbon sequestration. Monitoring of carbon and fluxes in soil is therefore an essential aspect in the era of changing climate. The root systems are monitored mostly in a destructive manner but many non-destructive methods have also been devised. Similarly, soil carbon estimation with traditional chemical method can be replaced by reflectance spectroscopy for rapid and large area estimations. Measurement of soil respiration and its partitioning also helps in verifying the capacity of soil as a net source or net sink. Monitoring of the pools and fluxes therefore uses multi-technique and -disciplinary approaches. Uncertainties in the estimates occur due to the multi-factorial effects and have implications on carbon trading. Therefore more effective monitoring and reduction of the uncertainties is needed. © 2013 Indian Society for Plant Physiology.