Mineralization pattern, mineral phases, and selected elemental analysis of the dorsal carapace of postecdysial blue crabs, Callinectes sapidus

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
Samantha Johnson (Creator)
Institution
The University of North Carolina Wilmington (UNCW )
Web Site: http://library.uncw.edu/
Advisor
Richard Dillaman

Abstract: The present investigation revealed the mineralization pattern, the mineral phases, and the selected elemental analysis of the dorsal carapace of the blue crab during postecdysis (1, 4, and 8 days) and intermolt (16 and 32 days) stages. Ten regions within the cuticle were examined using the scanning electron microscope (SEM) in secondary electron (SE), back-scattered electron (BSE), and x-ray microanalysis modes. X-ray microanalysis data were statistically analyzed using CATMOD (SAS). Amorphous mineral, presumably amorphous calcium carbonate (ACC) or amorphous calcium phosphate (ACP) was present in all regions of the cuticle and transformed to calcite or calcium phosphate over time in a spatial and temporal pattern for most regions. The middle and lower regions of the interprismatic septae were the only regions where the mineral did not transform with time. The statistical analyses of the quantitative data from x-ray microanalysis showed that the concentrations of selected elements relative to carbon and the P/Ca and Mg/Ca ratios changed within and among the regions of the cuticle over time. The results also suggested that there are three elementally distinct regions in the cuticle: the epicuticle and the distal exocuticle (EDE), the exocuticle, and the endocuticle. This study suggests that Callinectes sapidus uses ACC for its isotropic properties and as a precursor phase to a more stable, crystalline mineral. Amorphous mineral in combination with a crystalline phase may be used by blue crabs to create an exoskeleton with superior mechanical properties.

Additional Information

Publication
Thesis
A Thesis Submitted to the University of North Carolina at Wilmington in Partial Fulfillment of the Requirement for the Degree of Masters of Science
Language: English
Date: 2009
Keywords
Blue crab, Callinectes--Morphology, Callinectes--Physiology
Subjects
Blue crab
Callinectes -- Physiology
Callinectes -- Morphology