New directions in black carbon organic geochemistry

In the past 30 years, the field of black carbon (BC) research has expanded broadly, stretching from its traditional core in the atmospheric sciences into oceanography, soil science, and even anthropology. Results produced in this period of expansion have been exciting: BC has been detected in many important geochemical pools, and interesting new research directions open as we learn about the role of this byproduct of biomass burning in the carbon cycle. Especially important research directions will be the quantification of BC loss processes (both biotic and abiotic), measurement of BC decomposition products in environmentally relevant reservoirs, and exploration of the interactions between BC and its host organo-mineral matrix, including the role of BC in pedogenesis. However, along with exciting results, we have also seen apparent discrepancies between BC studies. These discrepancies occur at least in part because of a lack of a common language, common methods, and a common model of BC. This paper lays out the framework many BC researchers use to understand the role of BC in the carbon cycle, discussing the ‘combustion continuum’ BC model and the methodological continuum that this model implies.