Fig. 4: DOM elemental composition.

Elemental ratios H/CMF (a), O/CMF (b), N/CMF (c), S/CMF (d), P/CMF (e), and m/z (f) by water type. Boxplots display minimum, first quartile, median, third quartile, maximum, and outliers (black circles), including technical and analytical replicates (n = 35, gray dots) colored by water type.