Hydrozincite seasonal precipitation at Naracauli (Sardinia-Italy): hydrochemical factors and morphological features of the biomineralization process

Hydrozincite biomineralization occurs seasonally in the Naracauli creek (SW Sardinia). It depends on several factors, such as the rainfall intensity, hydraulic flow, metal concentration and biological activity. In this work, it is shown that the optimum conditions for hydrozincite precipitation are the attainment of solution saturation and Zn2+/CO3-2 molar ratio close to 1. Microscopic analysis of the morphological features of hydrozincite biomineralization shows that these are dependent on the hydraulic flow. Besides these hydrochemical factors, the biomineralization process also depends on other environmental factors, specifically rainfall intensity.