Amorphous and crystalline calcium carbonate distribution in the tergite cuticle of moulting Porcellio scaber (Isopoda, Crustacea)

Abstract

a b s t r a c tThe main mineral components of the isopod cuticle consists of crystalline magnesium calcite and amorphous calcium carbonate. During moulting isopods moult first the posterior and then the anterior half of the body. In terrestrial species calcium carbonate is subject to resorption, storage and recycling in order to retain significant fractions of the mineral during the moulting cycle. We used synchrotron X-ray powder diffraction, elemental analysis and Raman spectroscopy to quantify the ACC/calcite ratio, the mineral phase distribution and the composition within the anterior and posterior tergite cuticle during eight different stages of the moulting cycle of Porcellio scaber. The results show that most of the amorphous calcium carbonate (ACC) is resorbed from the cuticle, whereas calcite remains in the old cuticle and is shed during moulting. During premoult resorption of ACC from the posterior cuticle is accompanied by an increase within the anterior tergites, and mineralization of the new posterior cuticle by resorption of mineral from the anterior cuticle. This suggests that one reason for using ACC in cuticle mineralization is to facilitate resorption and recycling of cuticular calcium carbonate. Furthermore we show that ACC precedes the formation of calcite in distal layers of the tergite cuticle.

Textured fluorapatite bonded to calcium sulphate strengthen stomatopod raptorial appendages

“…To complement these fracture data, we also acquired Raman spectra in the impact regions. A Raman shift doublet near 3,000 cm À 1 corresponding to chitin, as well as minor bands in the range 1,300-1,400 cm À 1 also attributed to chitin 24 , were detected in the smasher dactyl club impact region but not in the spearer species (Fig. 7b).…”

Reconstructing skeletal fiber arrangement and growth mode in the coral <i>Porites lutea</i> (Cnidaria, Scleractinia): a confocal Raman microscopy study

“…than Cuif et al (2011) for Galaxea fascicularis. Nothdurft and Webb (2007) observed that a vertical extension of 384 µm equals 36 µm in lateral growth by tracking growth lines in a skeletal rod of Porites lobata. This vertical distance was deposited within 12 days (derived from mean growth rates for this species; see Nothdurft and Webb, 2007) and equals a lateral growth of 3 µm per day.…”

“…They are arranged along the central axis and surrounded by fibers that represent the bulk of the skeleton (e.g. Cohen and McConnaughey, 2003;Nothdurft and Webb, 2007). These different skeletal morphological levels reflect the complex arrangement of coral skeletal elements and are specific for each taxon.…”

“…1c) or to temporal differences in formation of different skeletal elements and areas, such as secondary thickening of septa and the formation of dissepiments at the base of the polyp. A better understanding of coral growth patterns is desirable in order to improve the interpretation of high-resolution proxy data (Nothdurft and Webb, 2007). The high spatial resolution (sub-micrometer scale) of confocal Raman microscopy (CRM) has been demonstrated to be ideally suited to describe the structural relation between organic and inorganic phases in biogenic materials (e.g.…”

“…The high spatial resolution (sub-micrometer scale) of confocal Raman microscopy (CRM) has been demonstrated to be ideally suited to describe the structural relation between organic and inorganic phases in biogenic materials (e.g. Hild et al, 2008;Nehrke and Nouet, 2011;Neues et al, 2011;Nehrke et al, 2012). Recently, one study (Zhang et al, 2011) used CRM to map the skeleton of a blue coral (Heliopora coerulea, Octocorallia).…”