Magnesian calcite overgrowths on calcite seeds from seawater (25°C) in the presence of humic acid

Abstract

Precipitation experiments were carried out using chemo-stat technique in order to determine the effect of humic acid on the precipitation rate and composition of magnesian calcite from seawater under laboratory conditions (25°C, 1 atm). Results of our study clearly show that the presence of humic acid in seawater reduces the precipitation rate of magnesian calcite. However, MgCO₃ composition in magnesian calcite overgrowths is not influenced by the presence of up to 9.2 mg C/l of humic acid.