Pyrogenic organic matter, or black carbon (BC), is derived from the incomplete combustion of biomass and fossil fuels, and is now recognized for its potential impact on soil chemistry, transport of pollutants, climate and global carbon cycling. Further, its impacts will likely grow due to increased climate change-related wildfires and intentional addition of BC (as biochar) to soils to enhance soil fertility and C sequestration. However, while knowledge of the properties of natural and anthropogenic particulate BC has increased in recent years, there has been relatively little study of the properties and cycling of pyrogenic dissolved organic matter (py-DOM). Although its release into the environment may have unrecognized C cycling and environmental impacts, py-DOM has been quantified in only a few systems using methods that have not been comprehensively evaluated. It is necessary to establish a strong foundation for progress in the field of BC research by examining the fundamental chemical properties and mechanisms associated with py-DOM production and fate and the chemical markers used to quantify it. To accomplish this, the proposed project will: 1) produce py-DOM from a logical series of BC solids, both freshly produced and ’aged’ via microbial and photic treatments, 2) chemically characterize these BC parent solids and their aqueous dissolved products using FTIR, Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) and 1- and 2-dimensional NMR, 3) examine py-DOM loss and transformation after mineral sorption and microbial and photodegradation treatments, and 4) quantify the yields of putative pyrogenic molecular markers; levoglucosan, benzenepolycarboxylic acids (BPCA) and oxygenated polycyclic aromatic hydrocarbons (O-PAH), from fresh and ’aged’ BC solids and leachates. Using the same methods and experiments, the leachates and leachate alteration products of potentially interfering non-pyrogenic terrestrial organic materials, some of which we have recently shown to contain ’BC-like’ compounds will also be examined.