Biolability of Fresh and Photodegraded Pyrogenic Dissolved Organic Matter From Laboratory?Prepared Chars

Pyrogenic dissolved organic matter (pyDOM) is known to be an important biogeochemical constituent of aquatic ecosystems and the carbon cycle. While recent studies have examined how pyDOM production, composition, photolability varies with parent pyrogenic solid material type, we lack understanding potential microbial mineralization transformation in biogeosphere. Thus, leachates oak, charred at 400 °C 650 °C, as well their photodegraded counterparts were incubated a soil-extracted consortium over 96 days. During incubation, significantly more was biomineralized from lower versus higher temperature char leachate (45% vs. 37% lost, respectively). Further, greater extents than fresh non-photodegraded counterparts. Kinetic modeling identified mineralizable pyDOC fractions half-lives 9–13 Proton nuclear magnetic resonance spectroscopy indicated that majority this loss could attributed low molecular weight constituents (i.e., simple alcohols acids). quantification benzenepolycarboxylic acid (BPCA) markers condensed aromatic compounds much lesser (4.4% 10.1% decrease yields ?BPCA-C 66 days oak pyDOM, respectively), but most biomineralization smaller clusters (four rings or less). These results highlight contrasting bioavailability different portions need examine both evaluate its role soil heterotrophy environmental fate hydrogeosphere.