Anisotropic lattice distortions in the mollusk-made aragonite: A widespread phenomenon

Pokroy, Boaz; Fitch, Andrew N.; Lee, Peter L.; Quintana, J. P.; Caspi, E. N.; Zolotoyabko, E.

doi:10.1016/j.jsb.2005.10.009

Cited by 133 publications

(185 citation statements)

References 15 publications

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“…Similar results have been achieved on a variety of biogenic calcium carbonates (Pokroy et al, 2006a(Pokroy et al, ,b, 2009Stolarski et al, 2007;Zolotoyabko et al, 2007;Reggi et al, 2014;Zolotoyabko, 2017), including corals, and have been attributed to the degradation of intra-crystalline SOM by heating. While Raman spectroscopy cannot be used to quantify the unit cell parameters with the precision of XRD, we expect the unit cell changes to manifest in the Raman ν 1 peak as (1) a decrease in FWHM due to decreased disorder, and (2) an increase in wavenumber due to the shorter bond lengths, and thus higher frequency vibrations, in the contracted unit cell.…”

Section: Insights From Annealing Experimentssupporting

confidence: 79%

“…However, if this is the case, then the lattice strains are not specific to organic matter produced by the coral and could be the result of removing seawater-sourced organic matter from the crystals. Another possibility is that no organic matter was removed or that lattice strains are unrelated to organic matter, which is consistent with the lack of any changes in the lattices of chemically bleached (i.e., treated with NaOCl) biogenic aragonites (Pokroy et al, 2006a;Nehrke et al, 2011). It is important to recognize that the changes in lattice parameters could result directly from the annealing process.…”

Section: Insights From Annealing Experimentsmentioning

confidence: 88%

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The Origin and Role of Organic Matrix in Coral Calcification: Insights From Comparing Coral Skeleton and Abiogenic Aragonite

DeCarlo¹,

Ren²,

Farfán³

2018

Front. Mar. Sci.

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Understanding the mechanisms of coral calcification is critical for accurately projecting coral reef futures under ocean acidification and warming. Recent suggestions that calcification is primarily controlled by organic molecules and the biological activity of the coral polyp imply that ocean acidification may not affect skeletal accretion. The basis for these suggestions relies heavily on correlating the presence of organic matter with the orientation and disorder of aragonite crystals in the skeleton, carrying the assumption that organic matter observed in the skeleton was produced by the polyp to control calcification. Here we use Raman spectroscopy to test whether there are differences in organic matter content between coral skeleton and abiogenic aragonites precipitated from seawater, both before and after thermal annealing (heating). We measured the background fluorescence and intensity of C-H bonding signals in the Raman spectra, which are commonly attributed to coral polyp-derived skeletal organic matrix (SOM) and have been used to map its distribution. Surprisingly, we found no differences in either fluorescence or C-H bonding between abiogenic aragonite and coral skeleton. Annealing reduced the molecular disorder in coral skeleton, potentially due to removal of organic matter, but the same effect was also observed in the abiogenic aragonites. The presence of organic molecules in the abiogenic aragonites is further supported by measurements of N content and δ 15 N. Together, our data suggest that some of what has been interpreted in previous studies as polyp-derived SOM may actually be seawater-sourced organic matter or some other signal not unique to biogenic aragonite. Finally, we create a high-resolution Raman map of a Pocillopora skeleton to demonstrate how patterns of fluorescence and elevated calcifying fluid aragonite saturation state ( Ar ) along centers of calcification are consistent with both biological and physico-chemical controls. Our aim is to advance discussion on biological mediation of calcification and the implications for coral resilience in a high-CO 2 world.

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Section: Insights From Annealing Experimentssupporting

confidence: 79%

Section: Insights From Annealing Experimentsmentioning

confidence: 88%

The Origin and Role of Organic Matrix in Coral Calcification: Insights From Comparing Coral Skeleton and Abiogenic Aragonite

DeCarlo¹,

Ren²,

Farfán³

2018

Front. Mar. Sci.

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“…Organics occur both within (intracrystalline; Pokroy et al, 2006;Jacob et al, 2008) and between (intercrystalline) CaCO 3 crystals. During shell formation, these organic components mediate biomineralization (Lowenstam, 1981;Veis, 2003).…”

Section: Introductionmentioning

confidence: 99%

Effect of organic matrices on the determination of the trace element chemistry (Mg, Sr, Mg/Ca, Sr/Ca) of aragonitic bivalve shells (<i>Arctica islandica</i>)—Comparison of ICP-OES and LA-ICP-MS data

Schöne¹,

Zhang²,

Jacob³

et al. 2010

Geochem. J.

109

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The element chemistry of biogenic carbonates can provide important data on past environments. However, the Sr/Ca and Mg/Ca ratios as well as the Mg and Sr concentrations of biological carbonates, especially aragonitic bivalves often depart from apparent thermodynamic equilibrium. When measured in situ by means of LA-ICP-MS, the Mg concentration is often substantially enriched (two-to threefold) near the organic-rich, annual growth lines. To test the hypothesis that some organic components exert a major influence on the skeletal metal content, the element chemistry of different shell components (insoluble organic matrix, IOM; dissolved CaCO 3 and soluble organics, SOM) of Arctica islandica was measured by means of ICP-OES and LA-ICP-MS. The ICP-OES data indicate that the IOM is strongly enriched in Mg (130 ppm) and depleted in Sr and Ca (10 ppm and 0.22 wt%, respectively) when compared to the whole biomineral (Mg: 68 to 99 ppm, Sr: 860 to 1,060 ppm, Ca: ~35.72 wt%). Although the average relative abundance of the IOM barely exceeds 0.46 wt%, its chemical composition in combination with its heterogeneous distribution across the shell can significantly increase estimates of the Mg concentration if measured in situ by LA-ICP-MS. Depending on the distribution of the IOM, the Ca concentration may be significantly lower locally than the average Ca concentration of the whole shell (35.72 wt%). If this remains undetected, the Mg concentration of shell portions with higher than average IOM content is overestimated by LA-ICP-MS and, conversely, the Mg concentration is underestimated in shell portions with lower than average IOM content. Removal of the IOM prior to the chemical analysis by LA-ICP-MS or mathematical correction for the IOMderived magnesium concentrations is therefore strongly advised. The different chemistry of the IOM may also exert a major control on the trace element to calcium ratios. Shell portions enriched in IOM will show up to 200 times higher Mg/ Ca and up to two times higher Sr/Ca ratios than the average shell of A. islandica. Without removal of the IOM prior to the analysis, Mg/Ca and Sr/Ca ratios of shell portions with higher IOM content cannot be used as paleothermometers. Because it is currently impossible to remove the IOM prior to chemical analyses by LA-ICP-MS, we recommend the use of wet chemical techniques (= possibility to separate and measure individual shell components) such as ICP-OES at the expense of lower sampling resolution. The results of this study will significantly improve our understanding of shellbased climate and environmental proxies.

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“…The final lattice constants do not display any significant dependency on pyrophosphate concentration indicating that only slight macrostrain is inflicted upon the crystals even though very specific interactions take place. This is in contrast to the impact of organic additives on CaCO 3 biominerals [33][34][35][36][37], ZnO [38,39], and apatite [25].…”

Section: Impact Of Pyrophosphatementioning

confidence: 83%

Pyrophosphate-Inhibition of Apatite Formation Studied by In Situ X-Ray Diffraction

Ibsen

Birkedal

2018

Minerals

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Abstract:The pathways to crystals are still under debate, especially for materials relevant to biomineralization, such as calcium phosphate apatite known from bone and teeth. Pyrophosphate is widely used in biology to control apatite formation since it is a potent inhibitor of apatite crystallization. The impacts of pyrophosphate on apatite formation and crystallization kinetics are, however, not fully understood. Therefore, we studied apatite crystallization in water by synchrotron in situ X-ray diffraction. Crystallization was conducted from calcium chloride (0.2 M) and sodium phosphate (0.12 M) at pH 12 where hydrogen phosphate is the dominant phosphate species and at 60 • C to allow the synchrotron measurements to be conducted in a timely fashion. Following the formation of an initial amorphous phase, needle shaped crystals formed that had an octacalcium phosphate-like composition, but were too small to display the full 3D periodic structure of octacalcium phosphate. At later growth stages the crystals became apatitic, as revealed by changes in the lattice constant and calcium content. Pyrophosphate strongly inhibited nucleation of apatite and increased the onset of crystallization from minute to hour time scales. Pyrophosphate also reduced the rate of growth. Furthermore, when the pyrophosphate concentration exceeded~1% of the calcium concentration, the resultant crystals had reduced size anisotropy suggesting that pyrophosphate interacts in a site-specific manner with the formation of apatite crystals.

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Anisotropic lattice distortions in the mollusk-made aragonite: A widespread phenomenon

Cited by 133 publications

References 15 publications

The Origin and Role of Organic Matrix in Coral Calcification: Insights From Comparing Coral Skeleton and Abiogenic Aragonite

The Origin and Role of Organic Matrix in Coral Calcification: Insights From Comparing Coral Skeleton and Abiogenic Aragonite

Effect of organic matrices on the determination of the trace element chemistry (Mg, Sr, Mg/Ca, Sr/Ca) of aragonitic bivalve shells (<i>Arctica islandica</i>)—Comparison of ICP-OES and LA-ICP-MS data

Pyrophosphate-Inhibition of Apatite Formation Studied by In Situ X-Ray Diffraction

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Anisotropic lattice distortions in the mollusk-made aragonite: A widespread phenomenon

Cited by 133 publications

References 15 publications

The Origin and Role of Organic Matrix in Coral Calcification: Insights From Comparing Coral Skeleton and Abiogenic Aragonite

The Origin and Role of Organic Matrix in Coral Calcification: Insights From Comparing Coral Skeleton and Abiogenic Aragonite

Effect of organic matrices on the determination of the trace element chemistry (Mg, Sr, Mg/Ca, Sr/Ca) of aragonitic bivalve shells (<i>Arctica islandica</i>)&mdash;Comparison of ICP-OES and LA-ICP-MS data

Pyrophosphate-Inhibition of Apatite Formation Studied by In Situ X-Ray Diffraction

Contact Info

Product

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Effect of organic matrices on the determination of the trace element chemistry (Mg, Sr, Mg/Ca, Sr/Ca) of aragonitic bivalve shells (<i>Arctica islandica</i>)—Comparison of ICP-OES and LA-ICP-MS data