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Your search keyword '"Li/Mg"' showing total 4 results
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4 results on '"Li/Mg"'

1. 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

2. 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

3. 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

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

Author

Stewart, Joseph A., Robinson, Laura F., Day, Russell D., Strawson, Ivo, Burke, Andrea, Rae, James W.B., Spooner, Peter T., Samperiz, Ana, Etnoyer, Peter J., Williams, Branwen, Paytan, Adina, Leng, Melanie J., Häussermann, Vreni, Wickes, Leslie N., Bratt, Rachael, and Pryer, Helena

Subjects
*SCLERACTINIA, *DEEP-sea corals, *OCEAN temperature, *TRACE metals, *CORALLINE algae, *CARBON isotopes, *METAL refining, *ALKALINE earth metals
Abstract

• Li/Mg shows strong relationship with temperature across all biogenic aragonites. • Aragonitic stylasterid Li/Mg is the most robust temperature proxy. • Li/Mg of high-Mg calcites also exhibit an exponential relationship to temperature. • Database of temperature proxy data compiled and corrected for interlaboratory bias. The Li/Mg, Sr/Ca and oxygen isotopic (δ 18 O) 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 (<20 °C) remain limited. Here we present skeletal Li/Mg, Sr/Ca, δ 18 O and carbon isotope (δ 13 C) data from live-collected specimens of aragonitic scleractinian corals (Balanophyllia, Caryophyllia, Desmophyllum, Enallopsammia, Flabellum, Lophelia , and Vaughanella), both aragonitic and high-Mg calcitic stylasterid genera (Stylaster and Errina), and shallow-water high-Mg calcite crustose coralline algae (Lithophyllum, Hydrolithon , and Neogoniolithon). We interpret these data in conjunction with results from previously explored taxa including aragonitic zooxanthellate scleractinia and foraminifera, and high-Mg calcite octocorals. We show that Li/Mg ratios covary most strongly with seawater temperature, both for aragonitic and high-Mg calcitic taxa, making for reliable and universal seawater temperature proxies. Combining all of our biogenic aragonitic Li/Mg data with previous calibration efforts we report a refined relationship to temperature: Li/Mg All Aragonite = 5.42 exp ⁡ (− 0.050 × T (° C)) (R 2 = 0.97). This calibration now permits paleo-temperature reconstruction to better than ±3.4 °C (95% prediction intervals) across biogenic aragonites, regardless of taxon, from 0 to 30 °C. For taxa in this study, aragonitic stylasterid Li/Mg offers the most robust temperature proxy (Li/Mg Stylasterid (Arag) = 5.64 exp ⁡ (− 0.046 × T (° C)) (R 2 = 0.95)) with a reproducibility of ±2.3 °C. For the first time, we show that high-Mg calcites have a similar exponential relationship with temperature, but with a lower intercept value (Li/Mg = 0.63 exp ⁡ (− 0.050 × T (° C) (R 2 = 0.92)). This calibration opens the possibility of temperature reconstruction using high-Mg calcite corals and coralline algae. The commonality in the relationship between Li/Mg and temperature transcends phylogeny and suggests a similar abiogenic trace metal incorporation mechanism. [ABSTRACT FROM AUTHOR]

Published
2020
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