The Secret Lives of Roots

Below-ground carbon, including roots, is a crucial factor in the overall carbon cycle. But how much carbon do roots transfer below ground, and how long does it stay? In their Perspective, [Trumbore and Gaudinski][1] highlight the report by [ Matamala et al .][2], who use a new isotope method to measure root lifetimes. Their results suggest that the bulk of fine root mass has a lifetime of 4 to 6 years. However, in situ studies of root growth and mortality generally yield much shorter lifetimes. Trumbore and Gaudinski suggest that these disparate results may be reconciled by acknowledging the complexity of root populations, and that sampling studies must reflect that complexity. [1]: http://www.sciencemag.org/cgi/content/full/302/5649/1344 [2]: http://www.sciencemag.org/cgi/content/short/302/5649/1385