Photodegradation of pyrogenic dissolved organic matter (Py-DOM): a combined photon counting and distribution-based FT-ICR MS study

Abstract

Quantitative systematic studies are needed to elucidate the both short and long-term environmental implications of increasing pyrogenic dissolved organic matter (Py-DOM) inputs associated with projected increase in wildfire activity over the next century. Time-resolved fluorescence spectroscopy and Fourier transform ion cyclotron resonance were used to characterize extracts of unaltered and pyrolyzed wood and plant material. Upon pyrolysis, extracts shifted from a predominantly phenolic signature to a carboxylic-rich alicyclic configuration. Photodegradation of extracts was commensurate with solar energy exposure. The rate of photodegradation and the degradable fraction of DOM was component driven. Results of this study point to a disproportionate energy-induced response in components common to lignocellulose-derived DOM. Further studies are required to elucidate the mechanistic aspect of photodegradation of DOM, and Py-DOM as relates to energy input.