The Characteristics and Biological Relevance of Inorganic Amorphous Calcium Carbonate (ACC) Precipitated from Seawater

• DOI: 10.1021/acs.cgd.9b00003
• Publication Date: 2019-07-03T19:14:21Z
• Authors: David Evans; Paul B. Webb; Kirsty Penkman; Roland Kröger; Nicola Allison
• Keywords: Amorphous calcium carbonate; Artificial seawater; Ocean Acidification

The importance of amorphous calcium carbonate (ACC) as a precursor phase in the biomineralization marine calcifiers is increasingly being reported, particularly presence ACC has been observed or inferred several major groups. Here, we investigate structure and conditions required for its precipitation from seawater-based solutions, with an emphasis on coinfluence system (pH, dissolved inorganic carbon (DIC) concentration), seawater Mg/Ca ratio, amino acids. We find that Mg2+ aspartic acid, glutamic glycine strongly inhibit precipitation. Moreover, were unable to precipitate chemistry within range thought characterize calcification site certain (i.e., DIC < 6 mM, pH 9.3), although substantial modification ratio (Mg/Casw) allowed at reduced implication this could be important component utilizing pathway. In addition, degree which Mg/Casw acids influences necessary [CO32–] dependent. At lower, more biologically relevant than typical much work, decreasing can result greater long-range order less water crystallization but facilitates considerably lower higher pH.