Electrochemical and Structural Modifications of Humic Acids in Aerobically and Anaerobically Incubated Peat

Exposure to oxygen and aerobic biological activity during drought periods alters the availability of terminal electron acceptors (TEA) in peat catotelm layer. We investigated changes electrochemical chemical characteristics humic acids (HA) induced by subjecting air-dried sphagnum oxidation or reduction a 90-day incubation experiment. Structural modifications HAs from anaerobically (HAred) aerobically (HAox) incubated were ATR-FTIR, UV–vis, EEM fluorescence spectroscopy. Number strength acid groups characterized titration, while redox properties cyclic voltammetry quantified coulometry with mediated (MEO). had small effects, but compared anaerobic incubation, decreased 20% capacity HA reduce radical ion 2,2′-Azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS●−), passing 2.77 ± 0.13 mmole- gHA−1 HAred 2.21 0.10 HAox. Pseudo-first-order transfer kinetic constants 13.3 1.2 s−1 for HAox 16.7 1.4 HAred. Alterations hydrological status have minor effects on actual situ organic TEA, if coupled intensified they may result significant variations greenhouse gases emissions.