Climate change impacts high-latitude ecosystems, accelerating permafrost thaw, altering hydrology, and affecting carbon cycling. In interior Alaska, we examined the influence of permafrost thaw on dissolved organic carbon (DOC) flux and temporal variation in carbon age across upland headwater streams in the Caribou-Poker Creeks Research Watershed (CPCRW), a boreal forest watershed underlain by discontinuous permafrost. Radiocarbon (¹⁴C) analysis, excitation-emission matrices (EEMs), and end-member mixing model analyses were used to understand DOC sources and transport in subcatchments of the CPCRW. Samples were collected across discharge and permafrost extent gradients. Initial ∆14C-DOC results indicate that DOC near headwaters is significantly older than DOC downstream, with ∆14C-DOC ranging 4,000 to <6,000 years among headwaters, and 2,000 to >4,000 years further downstream. Fluorescence spectroscopy, was used to identify fluorophores associated with terrestrial or microbial sources and track temporal and spatial variations in DOC composition in response to environmental factors such as wildfire, hydrologic change, and permafrost thaw. DOC flux was calculated as the product of stream discharge and DOC concentration to evaluate overall trends in carbon export. To test if carbon fluxes have changed, the measured concentrations of DOC, cation, and anion tracers were compared to values predicted by Bayesian end-member mixing models. To assess long-term hydrological pattern shifts, 20 years of water chemistry data from the Bonanza Creek Long-Term Ecological Research site will be analyzed. An initial linear mixed-effects model on DOC data from the summers of 2001-2023 showed an average yearly decrease in DOC of -8.3 μM (p<0.001).