mineralization rates of 13 C-PEG to 13 CO2 and (b, d) the corresponding cumulative mineralization extents expressed as CO2- C formed in percent of initially added PEG-13 C. Incubations in sediment of lake Rotsee (water-dispersed slurries, continuously stirred) and soil LUFA 6S (unsaturated pore water conditions, static) were run at 20°C under oxic conditions. Non-mineralized PEG-added C that remained in the sediment of lake Rotsee (e) and soil LUFA 6S (f) at the end of the incubations (i.e., CNon-Mineralized; in C in percent of total added PEG-13 C) plotted versus cumulative mineralization extents at the end of the incubations (i.e., CMineralized; as CO2-13 C in percent of total added PEG-13 C). Mass balances on PEG-added 13 C (i.e., CMineralized + CNon-Mineralized in % of total added PEG-13 C) were closed as shown by numbers close to 100% below the panels. Incubations were run in triplicates, (doublicates for Soil 6S; t0, dark blue due to limited incubator space and t3 light green due to flushing issues in the incubator) individual triplicate data are shown in panels (a-d), while averages and standard deviations (error bars) are shown in panels e and paned f.