摘要：Atmosphere-Biosphera Interaction in the Terrestrial Carbone Cycle. The global cycle of carbon can be considered as a sum of several partial cycles. Carbon isotopes can be used to characterize different partial cycles of carbon, to study the source-consumer relationship and the way this relationship is built. This research is focused on the method of obtaining the necessary information to determine the isotopic mark of terrestrial ecosystems respiration – called Keeling plots – and we presents the interpretation of the results obtained by using this method. The samples were collected from the air layers near the ground when the metabolism of plants is manifested, thus influencing the two parameters measured. We also want to point out the fact that the respiration flow it is added the CO2 flux from the soil produced by organic matter in the soil and the respiration of the roots in the ground. The way the isotopic composition of 13C changes when CO2 concentration changes suggests that, when there is additional CO2, which has d13C different from d13C of CO2 already present in the atmosphere, the isotopic composition of the total atmospheric CO2 will be in inverse proportion to the molar concentration.
