Aragonite Crystals within Codiacean Algae: Distinctive Morphology and Sedimentary Implications

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Science  11 Feb 1972:
Vol. 175, Issue 4022, pp. 624-626
DOI: 10.1126/science.175.4022.624


Morphologic studies of single crystals of aragonite within Codiacean algae reveal characteristic crystal forms produced by two distinctly different modes of calcification. Diagnostic serrated crystals (1 micrometer in length) of aragonite originating within the extracellular sheaths of capitular filaments are incorporated into modern lime sediments and may serve as effective tracers for particles of algal origin. Intracellular calcification within Penicillus dumetosus, previously unueported, is represented by doubly terminated aragonite crystals ranging in size from 48 to 160 micrometers.