Use of dissolved organic matter to support hydrologic investigations in a permafrost-dominated watershed

Pyrolysis-gas chromatography/mass spectrometry (py-GC/MS) is an analytical tool used to produce a “fingerprint” of dissolved organic matter (DOM) in water. Py-GC/MS fingerprinting was used in this research to lend insight into the complex subsurface hydrology of a permafrost-dominated watershed near Fairbanks, AK. Fingerprinting analysis was conducted on groundwater, artesian spring, and stream samples from two watersheds and used to characterize relationships between the individual samples and between the watersheds. Fingerprinting analyses supported the hypothesis that spring water emerging on opposite sides of a hydraulic divide was of the same origin. Results also supported the hypothesis that individual water samples and their probable origin could be distinguished from one another based on their DOM fingerprint alone. This type of analysis could be used for flow path characterization in other complex watersheds or for characterizing important properties of DOM, such as its potential to mobilize contaminants.