Seneca Randolph and Sophia Gomez at Florida State University are thanked for help with sample preparation for DOC analysis. Dr. Vennemann (University of Lausanne) and NOSAMS are thanked for water and carbon isotopic analysis, respectively. A portion of this work was funded by the Vanishing Glaciers Project from the NOMIS foundation. FT-ICR MS analysis was performed in the Ion Cyclotron Resonance User Facility at the National High Magnetic Field Laboratory, which is supported by the National Science Foundation Division of Chemistry and Division of Materials Research through DMR 16-44779, and the State of Florida. E.H. was supported by an award to Alaska EPSCoR from the National Science Foundation (OIA 1757348).
All software used for data processing are publicaly available: https://nationalmaglab.org/user-facilities/icr/icr-software.