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Published on: February 28, 2017
Aragonite Crystals within Codiacean Algae: Distinctive Morphology and Sedimentary Implications.
Science (New York, N.Y.)
|February 11, 1972
Summary
Two calcification methods in Codiacean algae produce distinct aragonite crystals. Serrated crystals act as tracers for algal particles, while intracellular crystals in Penicillus dumetosus are larger and doubly terminated.
Area of Science:
- Marine biology
- Geology
- Biomineralization
Background:
- Codiacean algae contribute significantly to marine carbonate sediments.
- Understanding algal calcification processes is crucial for marine geology and paleoclimate studies.
- Aragonite crystal morphology can provide insights into biological origins.
Purpose of the Study:
- To investigate the diverse crystal morphologies of aragonite produced by Codiacean algae.
- To differentiate between extracellular and intracellular calcification modes in these algae.
- To assess the potential of algal aragonite crystals as paleoenvironmental tracers.
Main Methods:
- Morphological analysis of aragonite crystals from Codiacean algae using microscopy.
- Characterization of crystal size, shape, and termination.
- Comparison of crystal forms from different calcification locations (extracellular vs. intracellular).
Main Results:
- Two distinct aragonite crystal forms were identified, corresponding to different calcification modes.
- Extracellular calcification yields diagnostic serrated aragonite crystals (approx. 1 micrometer).
- Intracellular calcification within Penicillus dumetosus produces larger, doubly terminated aragonite crystals (48–160 micrometers).
Conclusions:
- Codiacean algae exhibit at least two distinct biomineralization pathways for aragonite precipitation.
- The unique morphology of extracellular aragonite crystals makes them valuable tracers for identifying algal contributions to marine sediments.
- The discovery of intracellular calcification in Penicillus dumetosus expands our understanding of algal biomineralization diversity.
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