Box plot showing data distribution for estimates of dissolved phosphorus in Archean seawater with 0.67 mM of Si from 3.8 to 2.6 Ga from measured and literature P/Fe ratios (2, 16–22). Average dissolved P concentration for Archean is shown, while one standard deviation is illustrated by the shaded area. Modern seawater is shown for comparison (11). The right panel summarizes the previous estimates of P concentrations in the Archean ocean (e.g. (1) Jones et al. (7); (2) Planavsky et al. (5); (3) Rasmussen et al. (8)). The range of P concentration of Archean seawater increases when assuming that the sediments experienced a 50% loss during early diagenesis.