Algae calcium carbonate mineralization

Calcium carbonate minerals (CaCOs) are ubiquitous in biomineralizing systems, since they are in the skeletons of organisms ranging from bacteria and algae to humans, most commonly as calcite (rhomboedral) or aragonite (orthorhombic). Thus, their structures and compositions are highly diversified. Here, only some examples are discussed. 

Calcium carbonate minerals are deposited in a wide variety of bacteria, protozoa, algae, higher plants, and invertebrates (Table I). They are also formed, although not as frequently, in vertebrates. The major structural polymorphs identified in biological systems are calcite, aragonite, and vaterite, although there is also evidence for monohydrate, amorphous, and a range of Ca/Mg carbonate phases. 

Biomineralization, 36 137-139 calcium carbonate, 36 163-167 in algae, 36 166-167 gravity sensors, 36 164-166 carbonate/sulfate mineralization mechanisms, 36 171-175... 

Sedimentary calcium carbonates are formed as the shells of marine plants and animals. Biologically produced CaCOs consists primarily of two minerals aragonite and calcite. Shallow-water carbonates, primarily corals and shells of benthic algae (e.g. Halimeda) are heterogeneous in their mineralogy and chemical composition but are composed mainly of aragonite and magnesium-rich calcite (see Morse and Mackenzie (1990) for a discussion). Carbonate tests of microscopic plants and animals, most of which hve in the surface ocean (there are also benthic animals that produce carbonate shells), are primarily made of the mineral calcite, which composes the bulk of the CaCOs... 

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