Calcification in algae: Mechanisms and the role of metabolism

The deposition of CaCO3 by algae (calcification) is a widespread phenomenon and the deposits of either aragonite or calcite may be extra‐, inter‐, or intracellular. This variability in location and crystal isomorph suggests that different calcification mechanisms operate in different algal groups. Despite this difference, all algal calcification systems have some common features. These include the need for a suitable CaCO3‐crystal nucleation mechanism and the stimulation of calcification by photosynthesis. The physiology and biochemistry of algal calcification are discussed in relation to the above processes and compared to noncalcareous algae