Abstract
Biofouling is the formation of composite deposits consisting of living organic matter and inorganic salts. So far there is little mechanistic information on biofouling. In this work, the role of the presence of microalgae on the nucleation and growth of calcium carbonate from aqueous supersaturated solutions was investigated with free drift and constant supersaturation batch experiments, at 25°C. Living and dead microalgae colonies were used to inoculate aqueous solutions supersaturated with respect to calcium carbonate. The presence of algae accelerated the crystal growth of calcium carbonate while at the same time affected the nucleation process showing catalytic activity. Higher acceleration was found for higher microalgae populations. The extracellular components of the test microalgae are believed to play an important role on the nucleation and the subsequent rate of precipitation of calcite, which was the only polymorph found to grow on algae substrates. It is suggested that the polysaccharides present, exert a templating effect for the formation of the mineral phase on the organic matter.
