Fig. 3.

Heatmap showing Spearman correlation between oxidative potential indicators; this includes all measurements across four sites. Eh_G and Eh_C are the estimated SELF redox potentials based on GSH/GSSG (i.e. Eh_GSH-GSSG) and CSH/CSSC (i.e. Eh_CSH-CSSC) redox pair. AA, CSH, and GSH denote loss rates of these antioxidants (i.e. OP_AA, OP_CSH, and OP_GSH; nmol min⁻¹ m⁻³), and CSSC and GSSG denote the formation rates of the two oxidation products (nmol min⁻¹ m⁻³). Correlations are shown as coefficients × 100 and as color-coded ellipses. The latter can be seen as the visual illustration of scatterplots, with high positive correlations appearing as narrow ellipses at 45°and low correlations appearing as ovals.