Nevertheless, for ZAP-C 3 the CO2 partial pressure and temperature are higher than systems using DAC or relying on the solubility of CO2 in the sea water . A further advantage of the ZAP-C 3 system is that the injection of the CO2 source at the bottom of the unit, while insertion of fresh mineral occurs at the top of the unit, means that the highest CO2 concentration (and highest temperature) occurs where the mineral is partially carbonated and thus reacts slower.