Fig. 3.

UV absorbance (λ = 242 nm) versus volume of eluent (mL) for the seawater-soluble NOM fraction of the Craggie Burn. The UV signal (solid red curved line) represents the NOM and is superimposed with the conductivity signal (solid blue curved line), the chloride concentration (green-colored bar graph), and the sulfate concentration (brown-colored bar graph). The mobile phase is 4.5% methanol in ultrapure water. Flow rate is 0.1 mL min^− 1. The UV-absorbing NOM is clearly separated into three peaks (CB_0, CB_1 and CB_2). Larger molecules elute first, smaller molecules elute later.