Figure 3

Mean layer concentration trends of dissolved inorganic carbon components in Northeast Atlantic water masses versus atmospheric CO₂ concentration. Mean layer (a) total DIC concentration (μmol kg⁻¹) and its separation into (b) natural (DIC_nat, μmol kg⁻¹) and (c) anthropogenic (C_ant, μmol kg⁻¹) components versus atmospheric CO₂ concentration (ppm) for the main water masses in the Northeast Atlantic: NACW (cyan), MW (orange), LSW (purple) and upper and lower NADW (pink and light green). Only linear trends (μmol kg⁻¹ ppm⁻¹) with a statistical p-value < 0.001 (Supplementary Information Table S1) have been depicted, and the grey shading accounts for the trend errors. Uncertainties in the mean properties are two times the standard error of the mean (i.e., 95% confidence interval). The year of the cruise is represented in the upper x-axis.