The process of photosynthesis: carbon fixation and reduction
carbon isotopes found - Live Science
As you can see in the table above, almost all but three of the carbon isotopes are unstable and exist for very short periods of time, before they decay.
Carbon isotopes in biological carbonates: Respiration …
The ratio of 13C/12C for photosynthetic tissues of 22 aquatic species was unrelated to photosynthetic pathway. In three aquatic environments CAM and non-CAM species were shown to have similar δ13C values. Although these CAM species derive up to half of their net carbon gain through dark fixation their δ13C values are similar to associated non-CAM species in part because the carbon source for dark CO2 uptake is CO2 released, through respiration or decomposition, from organic carbon. Thus, the carbon source for CAM reflects previous isotope discrimination events. As carbon isotopes are not able to distinguish the photosynthetic pathway, there is good evidence that they may prove invaluable in the study of diffusional resistance to photosynthesis. Such evaluations require careful analysis of the photosynthetic pathway, carbon species utilized and δ13C value of the source carbon. Although stable carbon isotope values do not allow differentiation between CAM and non-CAM aquatic species, there is evidence that hydrogen isotopes may be able to distinguish these two groups. Aquatic CAM species were shown to accumulate greater levels of deuterium than associated non-CAM species.
Photosynthetic Fractionation of Carbon Isotopes | …
Environmental scientists measure the isotope signature of living and nonliving things by comparing 13C to 12C isotopes. This proportion, or ratio, of carbon isotopes (13C/12C) in plants is different from the ratio of carbon isotopes in the atmosphere. Because most plants prefer the 12C isotope, the ratio of 13C/12C in plants is lower than the ratio of 13C/12C in the atmosphere (where no biological process chooses one isotope over the other).