Atmospheric 210Pb as a tracer for soil organic carbon transport in a coniferous forest

Core soils and falling litter samples were collected in a Japanese cypress forest (Chamaecyparis obtusa) to determine the litter-fed 210Pbex and organic carbon transfer from the forest canopy to soil and their subsequent distribution. Of the canopy residing 210Pbex pool, litterfall annually transports 53% to the forest floor while it adds 117 g m−2 per year of organic carbon to the forest soil, implying that litterfall dynamics can influence the distribution of 210Pbex and soil organic carbon (SOC). 210Pbex and SOC showed identical profile shapes and strong correlation in spatial as well as along the soil depth, indicating that both are affected by a similar process. Given the ubiquitous natural source of 210Pbex, it is plausible to infer that radiolead can be a possible tracer to study the SOC redistribution at regional and global scales.