Origin and genesis of dissolved organic matter : a study by Py-GC/MS-IRMS

Dissolved organic matter (DOM) is influenced by the diversity of potential sources and processes which results in a heterogeneous mixture with a characteristic organic chemical signature for individual aquatic ecosystems. Reference samples (DFG-Special Research Program ROSIG) from natural systems such as a bog lake, groundwater and soil percolate but also from anthropogenically influenced systems like a brown coal processing waste water reservoir and a waste water treatment plant were taken to identify common characteristics and differences with respect to the origin and genesis of the DOM. This was achieved by a new analytical approach where fragments of the DOM resulting from thermal degradation (Curie-point pyrolysis at 773 K) were hromatographically separated, identified, and analyzed for their isotopic content (Py-GC/MS-IRMS). The applicability of the analytical method was manifested and additionally used for a comparison of the DOM from a bog lake with a set of samples from different depths of the surrounding moss vegetation.