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High voltage: The molecular properties of redox-active dissolved organic matter in northern high-latitude lakes

May 26, 2023

Redox-active functional groups in dissolved organic matter (DOM) are crucial for microbial electron transfer and methane emissions. However, the extent of aquatic DOM redox properties across northern high-latitude lakes and their relationships with DOM composition have not been thoroughly described. We quantified electron donating capacity (EDC) and electron accepting capacity (EAC) in lake DOM from Canada to Alaska and assessed their relationships with parameters from absorbance, fluorescence, and ultrahigh resolution mass spectrometry (FT-ICR MS) analyses. EDC and EAC are strongly tied to aromaticity and negatively related to aliphaticity and protein-like content. Redox-active formulae spanned a range of aromaticity, including highly unsaturated phenolic formulae, and correlated negatively with many aliphatic N and S-containing formulae. This distribution illustrates the compositional diversity of redox-sensitive functional groups and their sensitivity to ecosystem properties such as local hydrology and residence time. Finally, we developed a reducing index (RI) to predict EDC in aquatic DOM from FT-ICR MS spectra and assessed its robustness using riverine DOM. As the hydrology of the northern high-latitudes continues to change, we expect differences in the quantity and partitioning of EDC and EAC within these lakes, which have implications for local water quality and methane emissions.

Publication Year 2023
Title High voltage: The molecular properties of redox-active dissolved organic matter in northern high-latitude lakes
DOI 10.1021/acs.est.3c01782
Authors Martin R. Kurek, Fenix Garcia-Tigreros, Natalie A. Nichols, Gregory K. Druschel, Kimberly Wickland, Mark M. Dornblaser, Robert G. Striegl, Sydney F. Niles, Amy M. McKenna, Pieter J.K Aukes, Ethan D. Kyzivat, Chao Wang, Laurence C. Smith, Sherry L. Schiff, David Butman, Robert G.M. Spencer
Publication Type Article
Publication Subtype Journal Article
Series Title Environmental Science & Technology
Index ID 70244021
Record Source USGS Publications Warehouse
USGS Organization Geosciences and Environmental Change Science Center