Abstract
Carbon isotope ratios within nonliving organic matter (NLOM) reflect the processes and rates associated with its production, internal transformations, and ultimate fate. In this chapter, examples from marine and terrestrial systems that demonstrate the power of using isotopic tools to decipher NLOM sources and turnover rates are presented, similarities and differences in a variety of NLOM pools are explored, and new approaches for future study are suggested. The carbon isotopes C-13 and C-14 are emphasized, as they have been most widely applied to NLOM studies.
