Figure 4: Environmental and OC compositional controls on the age of carbon supporting freshwater microbial demand.
From: Utilization of ancient permafrost carbon in headwaters of Arctic fluvial networks

Δ14C values of DOC utilized (±propagated s.e.m.) in parallel incubations conducted (a) at 20 and 4 °C (n=19) and (b) under ambient and nutrient-enriched conditions (n=11). Dashed line represents 1:1 line. (c) Δ14C of mean DOC utilized across sites in relation to initial DOC aromaticity (inferred from SUVA254, see text for details). Decreasing SUVA254 indicates declining DOC aromaticity34.