Freshwater organic matter: Characteristics and reactivity

Freshwater organic matter acts as a key link between the landscape and the eventual fate of organic carbon in the modern carbon cycle, i.e., remineralization to CO2 or burial in sediments. As freshwater organic matter includes both organic matter fixed in situ and soil and land-plant-derived material, it encompasses a wide range of elemental stoichiometries and molecular formulas (intrinsic variables in terms of organic matter reactivity). The various freshwater systems themselves provide a wide range of environmental (or extrinsic) variables. The combined variations in extrinsic and intrinsic variables influence the reactivity of freshwater organic matter, ultimately driving the balance between organic matter remineralization and organic carbon burial.