Quantifying Litter Decomposition Losses to Dissolved Organic Carbon and Respiration.

As litter decomposes its carbon is lost from the terrestrial ecosystem to the atmosphere through microbial respiration.  However, much of the carbon lost from the litter layer during decomposition is not truly lost from the ecosystem but gets transferred from the litter layer to the soil through leaching of dissolved organic carbon (DOC).  This DOC in the soil acts as a stock of soil organic carbon to be utilized by microbes, stabilized in the soil, or leached further through the soil profile.  The rate of DOC leaching from litter to the soil, as well as its chemical composition has strong implications on the degradability or long-term storage of litter derived C in the soil.  In this study we aim to quantify a proportional relationship between CO₂ efflux and DOC production during decomposition of five types of litter.  Our results indicate that litter chemistry can be used to predict DOC production from CO₂ efflux measurements over different phases of decomposition based on litter chemical characteristics. Mid-IR-FTIR analyses of DOC and decomposing litter reveal the various compounds released as DOC during litter decomposition.  The ability to predict DOC leaching from litter to the soil based on litter chemistry and CO₂ efflux greatly enhances our ability to model carbon transformations during decomposition.