Calcium-alkalinity-nitrate relationship in the north pacific and the Japan Sea

When biogenic particles of calcium carbonate and organic matter are formed or decomposed in sea water, calcium concentration, alkalinity and nitrate concentration are changed according to the following equation: ΔCa=0.5 ΔTA+0.63 ΔNO ₃, where ΔCa, ΔTA and ΔNO ₃ are the differences in calcium, alkalinity and nitrate concentration, respectively, between two waters. This relationship was pointed out in a previous paper of ours, and it holds well for data obtained from the North Pacific and the Japan Sea. Furthermore, in sea water containing little or no nutrients, the variations in calcium concentration and alkalinity are consistent with the variations expected from the formation and dissolution of calcium carbonate alone.