Search

Your search keyword '"Li/Mg"' showing total 5 results
Start Over Descriptor "Li/Mg" Topic aragonite
5 results on '"Li/Mg"'

1. Controls of temperature and mineral growth rate on lithium and sodium incorporation in abiotic aragonite.

Author

Brazier, Jean-Michel, Harrison, Anna L., Rollion-Bard, Claire, and Mavromatis, Vasileios

Subjects
*TEMPERATURE control, *ARAGONITE, *CARBONATE minerals, *BIOGENIC amines, *MINERALS, *SURFACE defects
Abstract

The use of Li/Ca, Na/Ca and Li/Mg ratios in biogenic aragonite exhibits high potential for reconstructing environmental parameters such as temperature and/or salinity. To date however, only a little is known about the mechanisms controlling the incorporation of monovalent metals such as Li+ and Na+ in aragonite. In this study, the effects of temperature and growth rate on Li and Na incorporation into abiotically precipitated aragonite were experimentally investigated. The results for aragonite overgrowths at 5, 15 and 25 °C and for the surface normalized growth rate range 10–8.6 ≤ r p ≤ 10–7.1 (mol/m2/s) suggest that apparent distribution coefficients (i.e., D Me + = C Me + C Ca aragonite m Me + m Ca solution) of Li and Na are mainly controlled by mineral growth rate, whereas temperature has a minor effect. The combined effect of growth rate and temperature on D Li and D Na can be described as: Log D Li = 0.836 ± 0.028 Log r p − 0.026 ± 0.002 T + 2.958 ± 0.221 ; R 2 = 0.97 Log D Na = 0.456 ± 0.030 Log r p − 0.018 ± 0.002 T − 0.253 ± 0.234 ; R 2 = 0.90 where Log r p is the growth rate in mol/m2/s and T is the temperature in degrees Celsius. The D Li and D Na values increase at increasing mineral growth rate, but also decrease as a function of temperature in experiments with similar normalized growth rate. These observations suggest that the incorporation of Li and Na in abiotic aragonite is controlled by the density of mineral surface defect sites that are correlated with the degree of saturation of the reactive solution with respect to aragonite. Interestingly, no correlation between Li/Mg in the aragonite overgrowths and temperature of formation was observed in this study. This difference of Li/Mg and temperature correlations between abiotic aragonite and natural biogenic samples is intriguing and underlines the need for robust understanding of elemental incorporation during carbonate mineral formation, and proxy calibrations specific for growth conditions (e.g., abiotic versus biogenic). The results of this study do not support the use of Li/Mg as a temperature proxy in abiotic aragonite. • Mineral growth rate influences the D Li and D Na between aragonite and the fluids. • Temperature has a minor effect on D Li and D Na values compared to the growth rate. • Linear correlations between D Li and D Na and saturation exist at different temperatures. • Incorporation of Li and Na is likely controlled by the density of defect sites. • No correlation between Li/Mg in the aragonite overgrowths and temperature was found. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

2. A simple biomineralization model to explain Li, Mg, and Sr incorporation into aragonitic foraminifera and corals.

Author

Marchitto, T.M., Bryan, S.P., Doss, W., McCulloch, M.T., and Montagna, P.

Subjects
*BIOMINERALIZATION, *FORAMINIFERA, *BENTHIC ecology models, *CORAL ecology, *ARAGONITE
Abstract

In contrast to Li/Ca and Mg/Ca, Li/Mg is strongly anticorrelated with temperature in aragonites precipitated by the benthic foraminifer Hoeglundina elegans and a wide range of scleractinian coral taxa. We propose a simple conceptual model of biomineralization that explains this pattern and is consistent with available abiotic aragonite partition coefficients. Under this model the organism actively modifies seawater within its calcification pool by raising its [Ca 2+ ], using a pump that strongly discriminates against both Li + and Mg 2+ . Rayleigh fractionation during calcification effectively reverses this process, removing Ca 2+ while leaving most Li + and Mg 2+ behind in the calcifying fluid. The net effect of these two processes is that Li/Mg in the calcifying fluid remains very close to the seawater value, and temperature-dependent abiotic partition coefficients are expressed in the biogenic aragonite Li/Mg ratio. We further show that coral Sr/Ca is consistent with this model if the Ca 2+ pump barely discriminates against Sr 2+ . In H. elegans the covariation of Sr/Ca and Mg/Ca requires either that the pump more strongly discriminates against Sr 2+ , or that cation incorporation is affected by aragonite precipitation rate via the mechanism of surface entrapment. In either case Li/Mg is minimally affected by such ‘vital effects’ which plague other elemental ratio paleotemperature proxies. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

3. Coral Li/Mg thermometry: Caveats and constraints

Author

Marco Taviani, Louise Bordier, Ana Carolina Ruiz-Fernández, Claudio Mazzoli, Juan P. Carricart-Ganivet, Paolo Montagna, Malcolm T. McCulloch, Simonepietro Canese, Peter Scott, Eric Douville, Stéphanie Reynaud, Julie Trotter, Aleksey Sadekov, Joan-Albert Sanchez-Cabeza, Denis Allemand, Serguei Damián Rico-Esenaro, Kristan Cuny-Guirriec, Marine Canesi, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Géochrononologie Traceurs Archéométrie (GEOTRAC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Centre Scientifique de Monaco (CSM), Dipartimento di Geoscienze [Padova], Universita degli Studi di Padova, Istituto di Scienze Marine [Bologna] (ISMAR), Istituto di Science Marine (ISMAR ), Consiglio Nazionale delle Ricerche (CNR)-Consiglio Nazionale delle Ricerche (CNR), Biology Department - Woods Hole Oceanographic Institution, Woods Hole Oceanographic Institution (WHOI), Stazione Zoologica Anton Dohrn (SZN), Italian National Institute of Environmental Protection and Research (ISPRA), School of Earth and Environment (UWA), The University of Western Australia (UWA), Instituto de Ciencias del Mar y Limnologia, Universidad National Autonoma de Mexico, University of Cambridge [UK] (CAM), Lamont-Doherty Earth Observatory (LDEO), Columbia University [New York], Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Padova = University of Padua (Unipd), and National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)-National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)

Subjects
010504 meteorology & atmospheric sciences, Coral, [SDE.MCG]Environmental Sciences/Global Changes, Porites, Mineralogy, Caryophyllia, engineering.material, 010502 geochemistry & geophysics, 01 natural sciences, Li/Mg, chemistry.chemical_compound, scleractinian corals, Li/Mg, paleo-temperature proxy, organic matter, calcite contamination, Geochemistry and Petrology, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, calcite contamination, Organic matter, 14. Life underwater, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Madrepora oculata, organic matter, chemistry.chemical_classification, Calcite, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, biology, Aragonite, Geology, biology.organism_classification, paleo-temperature proxy, chemistry, 13. Climate action, [SDE]Environmental Sciences, engineering, Seawater, scleractinian corals
Abstract

The coral Li/Mg temperature proxy is revisited through an in-depth trace element analysis of scleractinians collected live from tropical to polar environments. The dataset consists of Li/Ca, Mg/Ca, Sr/Ca and Li/Mg ratios from 64 coral specimens belonging to 8 different taxa, including both reef-building zooxanthellate and cold-water non-zooxanthellate species, from a wide range of water temperature (-1 to 29.5 degrees C), salinity (34.71 to 38.61), and depth (3 to 670m). Our results showed that the reliability of the Li/Mg temperature proxy is strongly limited by the organic matter associated with the coral skeleton, which is most evident within the green bands observed in tropical corals. Organic-rich bands can double the Mg content otherwise present in the skeleton, which may ultimately lead to a temperature overestimation exceeding 15 degrees C. We found that this bias can be overcome by the treatment of coral skeletons with a specific oxidizing cleaning protocol. We also detected the presence of calcite deposits within the aragonite skeleton of some Antarctic living coral specimens, which strongly affects the robustness of the Li/Mg proxy given its temperature sensitivity of similar to 1.5 degrees C/1% calcite. Therefore, to obtain reliable reconstructions a correction needs to be applied when organic matter and/or calcite contamination is present, which requires the scrupulous assessment of the integrity of the aragonite prior to geochemical analyses. Given that some species entrap more organic matter than others, and that some are more prone to calcite contamination, a taxon-related effect is apparent. Here we show that the tropical species Porites spp., Pseudodiploria strigosa and Orbicella annularis, and the cold-water species Madrepora oculata, Caryophyllia antarctica and Flabellum impensum, are all suitable candidates for reconstructing seawater temperatures. The integrated results across a wide temperature range, from extreme cold to tropical shallow waters, yield an overall precision for the Li/Mg-temperature proxy of +/- 1.0 degrees C, as quantified by the standard error of estimates. If calculated from the 95% prediction intervals, the uncertainty of the temperature estimates is +/- 0.9 degrees C at 1 degrees C, +/- 1.5 degrees C at 12 degrees C and +/- 2.6 degrees C at 25 degrees C. However, the uncertainty for the tropical corals (e.g. Porites) can be reduced to +/- 0.6 degrees C if a Li/Mg and Sr/Ca multi-regression approach is applied.

Published
2019

4. Refining trace metal temperature proxies in cold-water scleractinian and stylasterid corals

Author

Peter T. Spooner, Rachael Bratt, Peter J. Etnoyer, Adina Paytan, Russell D. Day, Ana Samperiz, Melanie J. Leng, Branwen Williams, Andrea Burke, Helena Pryer, Vreni Häussermann, Joseph A. Stewart, James W. B. Rae, Leslie Wickes, Ivo Strawson, Laura F. Robinson, NERC, University of St Andrews. School of Earth & Environmental Sciences, and University of St Andrews. St Andrews Isotope Geochemistry

Subjects
010504 meteorology & atmospheric sciences, Balanophyllia, Scleractinia, Mineralogy, Caryophyllia, engineering.material, 010502 geochemistry & geophysics, 01 natural sciences, Li/Mg, chemistry.chemical_compound, Seawater temperature, Refining, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Trace metal, SDG 14 - Life Below Water, 0105 earth and related environmental sciences, Calcite, GE, biology, Aragonite, Coralline algae, DAS, biology.organism_classification, Geophysics, chemistry, Space and Planetary Science, Isotopes of carbon, Environmental chemistry, Stylasteridae, engineering, Environmental science, Crustose, Geology, GE Environmental Sciences
Abstract

Funding was provided by an Antarctic Bursary awarded to J.A.S., ERC and NERC grants awarded to L.F.R. (278705, NE/S001743/1, NE/R005117/1) and L.F.R. and J.W.B.R. (NE/N003861/1), and a NERC Stable isotope Grant. The Li/Mg, Sr/Ca and oxygen isotopic (δ18O) compositions of many marine biogenic carbonates are sensitive to seawater temperature. Corals, as cosmopolitan marine taxa with carbonate skeletons that can be precisely dated, represent ideal hosts for these geochemical proxies. However, efforts to calibrate and refine temperature proxies in cold-water corals (

Published
2020

5. A simple biomineralization model to explain Li, Mg, and Sr incorporation into aragonitic foraminifera and corals

Author

Paolo Montagna, Malcolm T. McCulloch, S. P. Bryan, Whitney Doss, Thomas M Marchitto, Department of Geological Sciences [Boulder], University of Colorado [Boulder], Colorado State University [Fort Collins] (CSU), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), The University of Western Australia (UWA), Istituto di Scienze Marine [Bologna] (ISMAR), Istituto di Science Marine (ISMAR ), Consiglio Nazionale delle Ricerche (CNR)-Consiglio Nazionale delle Ricerche (CNR), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)-National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Coral, Analytical chemistry, paleotemperature proxies, Mineralogy, Li/Ca, engineering.material, 010502 geochemistry & geophysics, 01 natural sciences, Li/Mg, Foraminifera, Mg/Ca, Sr/Ca, Geochemistry and Petrology, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Earth and Planetary Sciences (miscellaneous), 14. Life underwater, Rayleigh fractionation, 0105 earth and related environmental sciences, biology, Precipitation (chemistry), Aragonite, biology.organism_classification, biomineralization, Partition coefficient, Geophysics, Space and Planetary Science, engineering, Seawater, Geology, Biomineralization
Abstract

International audience; In contrast to Li/Ca and Mg/Ca, Li/Mg is strongly anticorrelated with temperature in aragonites precipitated by the benthic foraminifer Hoeglundina elegans and a wide range of scleractinian coral taxa. We propose a simple conceptual model of biomineralization that explains this pattern and is consistent with available abiotic aragonite partition coefficients. Under this model the organism actively modifies seawater within its calcification pool by raising its [Ca2+], using a pump that strongly discriminates against both Li+ and Mg2+. Rayleigh fractionation during calcification effectively reverses this process, removing Ca2+ while leaving most Li+ and Mg2+ behind in the calcifying fluid. The net effect of these two processes is that Li/Mg in the calcifying fluid remains very close to the seawater value, and temperature-dependent abiotic partition coefficients are expressed in the biogenic aragonite Li/Mg ratio. We further show that coral Sr/Ca is consistent with this model if the Ca2+ pump barely discriminates against Sr2+. In H. elegans the covariation of Sr/Ca and Mg/Ca requires either that the pump more strongly discriminates against Sr2+, or that cation incorporation is affected by aragonite precipitation rate via the mechanism of surface entrapment. In either case Li/Mg is minimally affected by such ‘vital effects’ which plague other elemental ratio paleotemperature proxies.

Published
2018

Catalog

Books, media, physical & digital resources
See catalog results