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Cappelli C, Pérez-Huerta A. Testing the Influence of Laser Pulse Energy and Rate in the Atom Probe Tomography Analysis of Minerals. Microsc Microanal 2023; 29:1137-1152. [PMID: 37749699 DOI: 10.1093/micmic/ozad057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 03/22/2022] [Accepted: 04/24/2023] [Indexed: 09/27/2023]
Abstract
The use of atom probe tomography (APT) for mineral analysis is contributing to fundamental studies in Earth Sciences. Meanwhile, the need for standardization of this technique is becoming evident. Pending the use of mineral standards, the optimization of analysis parameters is needed to facilitate the study of different mineral groups in terms of data collection and quality. The laser pulse rate and energy are variables that highly affect the atom evaporation process occurring during APT analysis, and their testing is important to forecast mineral behavior and obtain the best possible data. In this study, five minerals representative of major groups (albite, As-pyrite, barite, olivine, and monazite) were analyzed over a range of laser pulse energies (10-50 pJ) and rates (100-250 kHz) to assess output parameter quality and evaluate compositional estimate stoichiometry. Among the studied minerals, As-pyrite, with the higher thermal conductivity and lower band gap, was the most affected by the laser pulse variation. Chemical composition estimates equal or close to the general chemical formula were achieved for monazite and As-pyrite. The analysis of multihit events has proved to be the best strategy to verify the efficacy of the evaporation process and to evaluate the best laser pulse setting for minerals.
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Affiliation(s)
- Chiara Cappelli
- Department of Geological Sciences, The University of Alabama, 201 7th Ave. Tuscaloosa, AL 35487, USA
| | - Alberto Pérez-Huerta
- Department of Geological Sciences, The University of Alabama, 201 7th Ave. Tuscaloosa, AL 35487, USA
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Cappelli C, Pérez-Huerta A, Alam SB, Prozorov T. Atom Probe Tomography Analysis of Mica. Microsc Microanal 2021; 28:1-14. [PMID: 35179108 DOI: 10.1017/s1431927621012940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Laser-assisted atom probe tomography (APT) is a relatively new, powerful technique for sub-nanometric mineral and biomineral analysis. However, the laser-assisted APT analysis of highly anisotropic and chemically diverse minerals, such as phyllosilicates, may prove especially challenging due to the complex interaction between the crystal structure and the laser pulse upon applying a high electric field. Micas are a representative group of nonswelling clay minerals of relevance to a number of scientific and technological fields. In this study, a Mg-rich biotite was analyzed by APT to generate preliminary data on nonisotropic minerals and to investigate the effect of the crystallographic orientation on mica chemical composition and structure estimation. The difference in results obtained for specimens extracted from the (001) and (hk0) mica surfaces indicate the importance of both experimental parameters and the crystallography. Anisotropy of mica has a strong influence on the physicochemical properties of the mineral during field evaporation and the interpretation of APT data. The promising results obtained in the present study open the way to future innovative APT applications on mica and clay minerals and contribute to the general discussion on the challenges for the analysis of geomaterials by atom probe tomography.
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Affiliation(s)
- Chiara Cappelli
- Department of Geological Sciences, The University of Alabama, Tuscaloosa, AL35487, USA
| | - Alberto Pérez-Huerta
- Department of Geological Sciences, The University of Alabama, Tuscaloosa, AL35487, USA
- Alabama Museum of Natural History, The University of Alabama, Tuscaloosa, AL35487, USA
| | - Sardar B Alam
- Division of Materials Sciences and Engineering, Ames Laboratory, Ames, IA50011, USA
| | - Tanya Prozorov
- Division of Materials Sciences and Engineering, Ames Laboratory, Ames, IA50011, USA
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Kintsu H, Pérez-Huerta A, Ohtsuka S, Okumura T, Ifuku S, Nagata K, Kogure T, Suzuki M. Functional analyses of chitinolytic enzymes in the formation of calcite prisms in Pinctada fucata. Micron 2021; 145:103063. [PMID: 33862321 DOI: 10.1016/j.micron.2021.103063] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/25/2021] [Accepted: 03/26/2021] [Indexed: 11/24/2022]
Abstract
The mollusk shells present distinctive microstructures that are formed by small amounts of organic matrices controlling the crystal growth of calcium carbonate. The shell of Pinctada fucata has the prismatic layer consisting of prisms of single calcite crystals and the nacreous layer consisting of aragonite tablets. The calcite crystal of prisms contains small angle grain boundaries caused by a dense intracrystalline organic matrix network to improve mechanical strength. Previously, we identified chitin and chitinolytic enzymes as components of this intracrystalline organic matrix. In this study, to reveal the function of those organic matrices in calcium carbonate crystallization, calcites synthesized in chitin gel with or without chitinolytic enzymes were analyzed by using transmission electron microscope (TEM) and atom probe tomography (APT), showing ion clusters derived from chitin inside of a calcite and small angle grain boundaries at optimal chitinolytic concentration. Furthermore, we performed the experiment in which chitinase inhibitor was injected into a living P. fucata. Nanoindentation and electron back scattered diffraction (EBSD) show that mechanical properties and crystal orientation were changed. These results suggested that chitinolytic enzymes work cooperatively with chitin to regulate the crystal growth and mechanical properties of the prismatic layer.
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Affiliation(s)
- Hiroyuki Kintsu
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657, Japan; National Institute for Environmental Studies, Ibaraki, 305-8506, Japan.
| | - Alberto Pérez-Huerta
- Department of Geological Sciences, The University of Alabama, Tuscaloosa, AL, 35487, USA.
| | - Shigeru Ohtsuka
- Institute of Engineering Innovation, The University of Tokyo, Tokyo, 113-8656, Japan.
| | - Taiga Okumura
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
| | - Shinsuke Ifuku
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tottori, Tottori, 680-8552, Japan.
| | - Koji Nagata
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657, Japan.
| | - Toshihiro Kogure
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
| | - Michio Suzuki
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657, Japan.
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Cappelli C, Pérez-Huerta A. Effect of crystallographic orientation on atom probe tomography geochemical data? Micron 2020; 137:102910. [PMID: 32569861 DOI: 10.1016/j.micron.2020.102910] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 06/08/2020] [Accepted: 06/08/2020] [Indexed: 11/16/2022]
Abstract
The recent application of atom probe tomography (APT) to minerals is becoming a powerful tool to unravel geological information from the nanoscale perspective. Yet, there are still unknown fundamental aspects of this microscopy technique for geological applications and the potential crystallographic orientation effect is a significant one. Here, the influence of the crystallographic orientation on the quality of atom probe tomography geochemical data is investigated for two minerals with the same crystal system and different morphology: spinel (isometric, hexoctahedral, octahedron morphology) and galena (isometric, hexoctahedral, cube morphology). Two separate crystals of barite (orthorhombic, dipyramidal, prism morphology) were also analyzed to test the reproducibility of APT data. Despite the general absence of expected stoichiometry, overall bulk and isotopic chemical composition are not affected by crystallographic orientation. 3D data reconstructions of the specimens showed similar spatial distribution of the ion species for each mineral and 2D density maps showed identical (barite, galena) or specular (spinel) patterns for each pair of planes analyzed. Our findings indicate a negligible effect of the crystallographic orientation in APT geochemical data for standard highly symmetric minerals but also suggest the possible influence of the crystallographic structure and composition on the mineral stoichiometry and elements spatial distribution density.
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Affiliation(s)
- Chiara Cappelli
- Department of Geological Sciences, The University of Alabama, Tuscaloosa, AL 35487, USA.
| | - Alberto Pérez-Huerta
- Department of Geological Sciences, The University of Alabama, Tuscaloosa, AL 35487, USA
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Duquette A, McClintock JB, Amsler CD, Pérez-Huerta A, Milazzo M, Hall-Spencer JM. Effects of ocean acidification on the shells of four Mediterranean gastropod species near a CO 2 seep. Mar Pollut Bull 2017; 124:917-928. [PMID: 28823551 DOI: 10.1016/j.marpolbul.2017.08.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 08/02/2017] [Accepted: 08/04/2017] [Indexed: 06/07/2023]
Abstract
Marine CO2 seeps allow the study of the long-term effects of elevated pCO2 (ocean acidification) on marine invertebrate biomineralization. We investigated the effects of ocean acidification on shell composition and structure in four ecologically important species of Mediterranean gastropods (two limpets, a top-shell snail, and a whelk). Individuals were sampled from three sites near a volcanic CO2 seep off Vulcano Island, Italy. The three sites represented ambient (8.15pH), moderate (8.03pH) and low (7.73pH) seawater mean pH. Shell mineralogy, microstructure, and mechanical strength were examined in all four species. We found that the calcite/aragonite ratio could vary and increased significantly with reduced pH in shells of one of the two limpet species. Moreover, each of the four gastropods displayed reductions in either inner shell toughness or elasticity at the Low pH site. These results suggest that near-future ocean acidification could alter shell biomineralization and structure in these common gastropods.
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Affiliation(s)
- Ashley Duquette
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - James B McClintock
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - Charles D Amsler
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Alberto Pérez-Huerta
- Department of Geological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA
| | - Marco Milazzo
- Dipartimento di Scienze della Terra e del Mare, University of Palermo, 90123 Palermo, Italy
| | - Jason M Hall-Spencer
- Marine Biology and Ecology Research Centre, School of Marine Science and Engineering, Plymouth University, Plymouth, UK
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Coronado I, Pérez-Huerta A, Rodríguez S. Analogous biomineralization processes between the fossil coral Calceola sandalina (Rugosa, Devonian) and other Recent and fossil cnidarians. J Struct Biol 2016; 196:173-186. [PMID: 27327265 DOI: 10.1016/j.jsb.2016.06.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 06/12/2016] [Accepted: 06/17/2016] [Indexed: 11/18/2022]
Abstract
The current work represents a distinctive study about the biomineral properties of exceptionally good preserved skeletons of Calceola sandalina from the Middle Devonian of Couvin (Belgium), Smara (Morocco) and (Algeria) and their relation in the evolution of biomineralization of cnidarians. Structural and crystallographic analyses of the skeletons have been done by petrographic microscopy, electron scanning microscopy (SEM), atomic force microscopy (AFM), electron backscatter diffraction (EBSD), computer-integrated polarization microscopy (CIP) and electron microprobe analysis (EMPA). Calceola skeletons have many similarities with other cnidarians, mainly with other Palaeozoic corals as Syringoporicae: The microcrystals are composed of co-oriented nanocrystals that remind to mesocrystals, suggesting a biocrystallization process by particle attachment (CPA). The relationship between the nanocrystals and microcrystals suggest a growth mode similar to mineral bridges. A similar model was described for Syringoporicae corals (Tabulata) and it is similar to the coordinated-growth mode described in scleractinians and molluscs. Calceola skeletons show also a convergent structure with scleractinian forming Rapid Accretion Deposits (RAD), which share some structural and chemical properties. These evidences suggest analogous processes of biomineralization derived from a stem group of cnidarians. The results of this paper highlight the value of biomineralization studies in fossil organisms to understand the evolution of biomineralization mechanism through Phanerozoic.
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Affiliation(s)
- Ismael Coronado
- Departamento de Paleontología, Universidad Complutense de Madrid, C/ José Antonio Nováis 2, Ciudad Universitaria, E-28040 Madrid, Spain.
| | - Alberto Pérez-Huerta
- Department of Geological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA.
| | - Sergio Rodríguez
- Departamento de Paleontología, Universidad Complutense de Madrid, C/ José Antonio Nováis 2, Ciudad Universitaria, E-28040 Madrid, Spain; Instituto de Geociencias (IGEO. CSIC-UCM), C/ José Antonio Nováis 2, Ciudad Universitaria, E-28040 Madrid, Spain.
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Pérez-Huerta A, Dauphin Y. Comparison of the structure, crystallography and composition of eggshells of the guinea fowl and graylag goose. ZOOLOGY 2015; 119:52-63. [PMID: 26711013 DOI: 10.1016/j.zool.2015.11.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 08/22/2015] [Accepted: 11/15/2015] [Indexed: 11/29/2022]
Abstract
The structure and composition of the eggshells of two commercial species (guinea fowl and greylag goose) have been studied. Thin sections and scanning electron microcopy show the similarity of the overall structure, but the relative thickness of the layers differs in these two taxa. Atomic force microscopy shows that the different layers are composed of rounded, heterogeneous granules, the diameter of which is between 50 and 100 nm, with a thin cortex. Infrared data and thermogravimetric analyses show that both eggshells are made of calcite, but differing on the quality and quantity when the organic component is considered. Chemical maps show that chemical element distribution is not uniform within a sample, and differs between the species, but with low magnesium content. Electron back scattered diffraction confirms the eggshells are calcite, but the microtexture strongly differs between the two species. Based on the chemical-structural differences, a species-specific biological control on the biomineralization is found, despite the rapid formation of an eggshell. Overall results indicate that to estimate the quality of eggshells, such as resistance to breakage, is not a straightforward process because of the high complexity of avian eggshell biomineralization.
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Affiliation(s)
- Alberto Pérez-Huerta
- Department of Geological Sciences, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Yannicke Dauphin
- UFR TEB, Université P. & M. Curie, case 104, 4 place Jussieu, 75252 Paris cedex 05, France.
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Hancock LG, Walker SE, Pérez-Huerta A, Bowser SS. Population Dynamics and Parasite Load of a Foraminifer on Its Antarctic Scallop Host with Their Carbonate Biomass Contributions. PLoS One 2015; 10:e0132534. [PMID: 26186724 PMCID: PMC4505869 DOI: 10.1371/journal.pone.0132534] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 06/15/2015] [Indexed: 11/19/2022] Open
Abstract
We studied the population dynamics and parasite load of the foraminifer Cibicides antarcticus on its host the Antarctic scallop Adamussium colbecki from three localities differing by sea ice cover within western McMurdo Sound, Ross Sea, Antarctica: Explorers Cove, Bay of Sails and Herbertson Glacier. We also estimated CaCO3 biomass and annual production for both species. Cibicides populations varied by locality, valve type, and depth. Explorers Cove with multiannual sea ice had larger populations than the two annual sea ice localities, likely related to differences in nutrients. Populations were higher on Adamussium top valves, a surface that is elevated above the sediment. Depth did not affect Cibicides distributions except at Bay of Sails. Cibicides parasite load (the number of complete boreholes in Adamussium valves) varied by locality between 2% and 50%. For most localities the parasite load was < 20%, contrary to a previous report that ~50% of Cibicides were parasitic. The highest and lowest parasite load occurred at annual sea ice localities, suggesting that sea ice condition is not important. Rather, the number of adults that are parasitic could account for these differences. Cibicides bioerosion traces were categorized into four ontogenetic stages, ranging from newly attached recruits to parasitic adults. These traces provide an excellent proxy for population structure, revealing that Explorers Cove had a younger population than Bay of Sails. Both species are important producers of CaCO3. Cibicides CaCO3 biomass averaged 47-73 kg ha(-1) and Adamussium averaged 4987-6806 kg ha(-1) by locality. Annual production rates were much higher. Moreover, Cibicides represents 1.0-2.3% of the total host-parasite CaCO3 biomass. Despite living in the coldest waters on Earth, these species can contribute a substantial amount of CaCO3 to the Ross Sea and need to be incorporated into food webs, ecosystem models, and carbonate budgets for Antarctica.
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Affiliation(s)
- Leanne G. Hancock
- Department of Geology, University of Georgia, Athens, Georgia, United States of America
| | - Sally E. Walker
- Department of Geology, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
| | - Alberto Pérez-Huerta
- Department of Geological Sciences, University of Alabama, Tuscaloosa, Alabama, United States of America
| | - Samuel S. Bowser
- Wadsworth Center, New York State Department of Health, Albany, New York, United States of America
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Pérez-Huerta A, Etayo-Cadavid MF, Andrus CFT, Jeffries TE, Watkins C, Street SC, Sandweiss DH. El Niño impact on mollusk biomineralization-implications for trace element proxy reconstructions and the paleo-archeological record. PLoS One 2013; 8:e54274. [PMID: 23405078 PMCID: PMC3566134 DOI: 10.1371/journal.pone.0054274] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 12/10/2012] [Indexed: 11/23/2022] Open
Abstract
Marine macroinvertebrates are ideal sentinel organisms to monitor rapid environmental changes associated with climatic phenomena. These organisms build up protective exoskeletons incrementally by biologically-controlled mineralization, which is deeply rooted in long-term evolutionary processes. Recent studies relating potential rapid environmental fluctuations to climate change, such as ocean acidification, suggest modifications on carbonate biominerals of marine invertebrates. However, the influence of known, and recurrent, climatic events on these biological processes during active mineralization is still insufficiently understood. Analysis of Peruvian cockles from the 1982–83 large magnitude El Niño event shows significant alterations of the chemico-structure of carbonate biominerals. Here, we show that bivalves modify the main biomineralization mechanism during the event to continue shell secretion. As a result, magnesium content increases to stabilize amorphous calcium carbonate (ACC), inducing a rise in Mg/Ca unrelated to the associated increase in sea-surface temperature. Analysis of variations in Sr/Ca also suggests that this proxy should not be used in these bivalves to detect the temperature anomaly, while Ba/Ca peaks are recorded in shells in response to an increase in productivity, or dissolved barium in seawater, after the event. Presented data contribute to a better understanding of the effects of abrupt climate change on shell biomineralization, while also offering an alternative view of bivalve elemental proxy reconstructions. Furthermore, biomineralization changes in mollusk shells can be used as a novel potential proxy to provide a more nuanced historical record of El Niño and similar rapid environmental change events.
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Affiliation(s)
- Alberto Pérez-Huerta
- Department of Geological Sciences, The University of Alabama, Tuscaloosa, AL, USA.
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Pérez-Huerta A, Dauphin Y, Cusack M. Biogenic calcite granules—Are brachiopods different? Micron 2013; 44:395-403. [DOI: 10.1016/j.micron.2012.09.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 08/28/2012] [Accepted: 09/04/2012] [Indexed: 10/27/2022]
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Carmichael RH, Jones AL, Patterson HK, Walton WC, Pérez-Huerta A, Overton EB, Dailey M, Willett KL. Assimilation of oil-derived elements by oysters due to the Deepwater Horizon Oil Spill. Environ Sci Technol 2012; 46:12787-12795. [PMID: 23131011 DOI: 10.1021/es302369h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
During and after the Deepwater Horizon Oil Spill (DWHOS), oysters (Crassostrea virginica) were exposed to oil and susceptible to incidental consumption of surface and subsurface oil materials. We determined the contribution of oil materials from the DWHOS to diet of oysters by comparing carbon (C) and nitrogen (N) stable isotope ratios in oyster shell to ratios in suspended particulate matter (SPM) and in fresh and weathered oil. Average δ(13)C and δ(15)N values in oyster shell (-21 ± 1‰ and 9-11‰, respectively) were consistent with consumption of naturally available SPM as opposed to values in oil (-27 ± 0.2‰, 1.6 ± 0.4‰). Stable isotope ratios in oyster adductor muscle were similar to shell for δ(15)N but not δ(13)C, suggesting either a recent shift in diet composition or differential assimilation of C between tissue types. We found no evidence of assimilation of oil-derived C and N and, therefore, no evidence of an oyster-based conduit to higher trophic levels. Trace elements in shell were inconclusive to corroborate oil exposure. These findings are not an indication that oysters were not exposed to oil; rather they imply oysters either did not consume oil-derived materials or consumed too little to be detectable compared to natural diet.
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Pérez-Huerta A, Dauphin Y, Cuif JP, Cusack M. High resolution electron backscatter diffraction (EBSD) data from calcite biominerals in recent gastropod shells. Micron 2011; 42:246-51. [DOI: 10.1016/j.micron.2010.11.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 11/04/2010] [Accepted: 11/04/2010] [Indexed: 10/18/2022]
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Moureaux C, Pérez-Huerta A, Compère P, Zhu W, Leloup T, Cusack M, Dubois P. Structure, composition and mechanical relations to function in sea urchin spine. J Struct Biol 2010; 170:41-9. [DOI: 10.1016/j.jsb.2010.01.003] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Revised: 12/28/2009] [Accepted: 01/02/2010] [Indexed: 11/29/2022]
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Abstract
Electron backscatter diffraction (EBSD) is becoming a widely used technique to determine crystallographic orientation in biogenic carbonates. Despite this use, there is little information available on preparation for the analysis of biogenic carbonates. EBSD data are compared for biogenic aragonite and calcite in the common blue mussel, Mytilus edulis, using different types of resin and thicknesses of carbon coating. Results indicate that carbonate biomineral samples provide better EBSD results if they are embedded in resin, particularly epoxy resin. A uniform layer of carbon of 2.5 nm thickness provides sufficient conductivity for EBSD analyses of such insulators to avoid charging without masking the diffracted signal. Diffraction intensity decreases with carbon coating thickness of 5 nm or more. This study demonstrates the importance of optimizing sample preparation for EBSD analyses of insulators such as carbonate biominerals.
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Affiliation(s)
- Alberto Pérez-Huerta
- Department of Geographical and Earth Sciences, University of Glasgow, G12 8QQ Glasgow, UK.
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Pérez-Huerta A, Cusack M, McDonald S, Marone F, Stampanoni M, MacKay S. Brachiopod punctae: a complexity in shell biomineralisation. J Struct Biol 2009; 167:62-7. [PMID: 19341799 DOI: 10.1016/j.jsb.2009.03.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Revised: 03/24/2009] [Accepted: 03/25/2009] [Indexed: 11/27/2022]
Abstract
Perforations ("punctae") are one of the most characteristic morphological shell features in calcite brachiopods. The significance of punctae is that they represent discontinuities in shell biomineralisation and thus add a level of complexity that must be accounted for in any model of brachiopod shell formation. A significant hindrance to understanding punctae growth and formation is the absence of sufficient information on volume, size and density. Here, we use synchrotron-radiation X-ray tomographic microscopy (SRXTM) to obtain three-dimensional information about punctae of five species of calcite brachiopods. X-ray tomography shows that punctae morphology is species-specific and reveals previously unknown levels of complexity for each species. This information is combined with previous data on morphology to discuss the function and growth of punctae. Overall the present study demonstrates the need to increase our understanding of discontinuities and the role of cell biology in the context of biomineralisation.
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Affiliation(s)
- A Pérez-Huerta
- Dept. of Geographical & Earth Sciences, University of Glasgow, G12 8QQ Glasgow, UK.
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Pérez-Huerta A, Cusack M, Janousch M, Finch AA. Influence of crystallographic orientation of biogenic calcite on in situ Mg XANES analyses. J Synchrotron Radiat 2008; 15:572-575. [PMID: 18955762 DOI: 10.1107/s0909049508026484] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Accepted: 08/17/2008] [Indexed: 05/27/2023]
Abstract
Micro X-ray absorption near-edge spectroscopy at the Mg K-edge is a useful technique for acquiring information about the environment of Mg(2+) in biogenic calcite. These analyses can be applied to shell powders or intact shell structures. The advantage of the latter is that the XANES analyses can be applied to specific areas, at high (e.g. micrometre) spatial resolution, to determine the environment of Mg(2+) in a biomineral context. Such in situ synchrotron analysis has to take into account the potential effect of crystallographic orientation given the anisotropy of calcite crystals and the polarized nature of X-rays. Brachiopod shells of species with different crystallographic orientations are used to assess this crystallographic effect on in situ synchrotron measurements at the Mg K-edge. Results show that, owing to the anisotropy of calcite, in situ X-ray absorption spectra (XAS) are influenced by the crystallographic orientation of calcite crystals with a subsequent potentially erroneous interpretation of Mg(2+) data. Thus, this study demonstrates the importance of crystallography for XAS analyses and, therefore, the necessity to obtain crystallographic information at high spatial resolution prior to spectroscopic analysis.
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Cusack M, Dauphin Y, Chung P, Pérez-Huerta A, Cuif JP. Multiscale structure of calcite fibres of the shell of the brachiopod Terebratulina retusa. J Struct Biol 2008; 164:96-100. [DOI: 10.1016/j.jsb.2008.06.010] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Revised: 06/15/2008] [Accepted: 06/16/2008] [Indexed: 11/15/2022]
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Abstract
Mineral-producing organisms exert exquisite control on all aspects of biomineral production. Among shell-bearing organisms, a wide range of mineral fabrics are developed reflecting diverse modes of life that require different material properties. Our knowledge of how biomineral structures relate to material properties is still limited because it requires the determination of these properties on a detailed scale. Nanoindentation, mostly applied in engineering and materials science, is used here to assess, at the microstructural level, material properties of two calcite brachiopods living in the same environment but with different modes of life and shell ultrastructure. Values of hardness (H) and the Young modulus of elasticity (E) are determined by nanoindentation. In brachiopod shells, calcite semi-nacre provides a harder and stiffer structure (H approximately 3-6 GPa; E=60-110/120 GPa) than calcite fibres (H=0-3 GPa; E=20-60/80 GPa). Thus, brachiopods with calcite semi-nacre can cement to a substrate and remain immobile during their adult life cycle. This correlation between mode of life and material properties, as a consequence of ultrastructure, begins to explain why organisms produce a wide range of structures using the same chemical components, such as calcium carbonate.
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Affiliation(s)
- Alberto Pérez-Huerta
- Department of Geographical and Earth Sciences, University of GlasgowGlasgow G12 8QQ, UK
| | - Maggie Cusack
- Department of Geographical and Earth Sciences, University of GlasgowGlasgow G12 8QQ, UK
- Author for correspondence ()
| | - Wenzhong Zhu
- Scottish Centre for Nanotechnology in Construction Materials, School of Engineering and Sciences, University of PaisleyPaisley PA1 2BE, UK
| | - Jennifer England
- Department of Geographical and Earth Sciences, University of GlasgowGlasgow G12 8QQ, UK
| | - John Hughes
- Scottish Centre for Nanotechnology in Construction Materials, School of Engineering and Sciences, University of PaisleyPaisley PA1 2BE, UK
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