Figure 1. Seawater chemistry over the Control and High CO₂ tiles.

Black horizontal lines indicate medians; boxes enclose the upper and lower quartiles of the data, whiskers mark the maximum and minimum values excluding outliers, while round circles show outliers. The plots show the median values of 45 Control and 71 High CO₂ tiles, with each of these 45 and 71 median values composed of 4 to 23 measurements taken directly over each of the tiles during four two-week long visits in the period 2011–2012 (data are listed in the Supplementary Tables S1 and S2, online). pH is at total scale, Omega calcite and aragonite = saturation states of calcite and aragonite, TA = total alkalinity, DIC = dissolved inorganic carbon.