RADIOCARBON CONCENTRATION IN SHORT-LIVED HERBACEOUS PLANTS AS INDICATOR OF FOSSIL CO2 EMISSIONS IN URBAN REGIONS
Plant biomass incorporates 14C from the atmospheric CO2 so can potentially be used as indicators of the carbon isotopic composition of the local atmosphere at either high temporal resolution using short-lived plants, or at annual resolution using annual plants and tree-rings.
The aim of this study is to evaluate widely distributed short-lived plants as cheap and easy to sample bioindicators of atmospheric 14C variations related to fossil CO2 emissions with a high temporal resolution. We present a comparison between 14C data from integrated CO2 samples with two species of grass (Stenotaphrum secundatum and Lolium perenne) growing at the same sampling site inside Mexico City for the period 2008 – 2011. The main results suggest that both plant species do record variations in 14C atmospheric concentrations, showing similar trends to those found for integrated CO2 samples. This indicates that the carbon contained in leafs of both studied plant species has been recently assimilated. It can be concluded that it is possible to estimate fossil CO2 emissions with high temporal resolution from 14C concentrations in grasses growing in urban areas.