Morphological and cytological aspects of algal calcification

Borowitzka, M.A.ORCID: 0000-0001-6504-4563 (1982) Morphological and cytological aspects of algal calcification. In: Bourne, G.H., Danielli, J.F. and Jeon, K.W., (eds.) International Review of Cytology Volume 74. Elsevier Inc., pp. 127-162.

Abstract

This chapter discusses the morphological and cytological aspects of algal calcification. The deposition of calcium salts may occur either extra, inter, or intracellularly. The calcium carbonate is deposited as either the aragonite or the calcite crystal isomorph, and mixtures of the two isomorphs do not occur. The CaCO3-impregnated cell walls in algae make them important sediment and reef-forming organisms. The cell walls of vegetative cells, with the exception of the walls of the genicula, hair cells, and the walls of some cells surrounding the conceptacles, contain extensive deposits of the calcite crystal isomorph of CaCO3 mixed with some magnesium carbonate. Crystal formation basically requires two steps— namely, crystal nucleation and crystal growth (crystallization). Algae, in general, secrete a wide range of organic molecules, and it is possible that these molecules inhibit CaCO3 nucleation and therefore, calcification. Calcium carbonate is not the only mineral deposit formed by algae. Aside from the large and delicately sculpted deposits of silica formed by diatoms and some other algae, algae also deposits calcium oxalate, barium sulfate, and more rarely other mineral salts.

Item Type:	Book Chapter
Publisher:	Elsevier Inc.
Copyright:	© 1982 Academic Press Inc.
URI:	http://researchrepository.murdoch.edu.au/id/eprint/48027

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