Interlaboratory comparison study of Mg/Ca and Sr/Ca measurements in planktonic foraminifera for paleoceanographic research

• Published in: Geochemistry, Geophysics, Geosystems
• Main Authors: Rosenthal, Y, Perron-Cashman, S, Lear, Ch, Bard, E., Barker, S, Billups, K, Bryan, M, Delaney, ML, deMenocal, PB, Dwyer, GS, Elderfield, H, German, CR, Greaves, M, Lea, DW, Marchitto, TM, Pak, DK, Paradis, GL, Russell, AD, Schneider, RR, Scheiderich, K, Stott, L, Tachikawa, K, Tappa, E, Thunell, R, Wara, M, Weldeab, S, Wilson, PA
• Other Authors: Rutgers, The State University of New Jersey New Brunswick (RU), Rutgers University System (Rutgers), IMCS, Rutgers University System (Rutgers)-Rutgers University System (Rutgers), School of Earth and Ocean Sciences Cardiff, Cardiff University, Chaire Evolution du climat et de l'océan, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Department of Earth Sciences Cambridge, UK, University of Cambridge UK (CAM)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2004
• Subjects: [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph]; Planktonic foraminifera
• Online Access: https://hal.archives-ouvertes.fr/hal-01463331; https://hal.archives-ouvertes.fr/hal-01463331/document; https://hal.archives-ouvertes.fr/hal-01463331/file/2003GC000650.pdf; https://doi.org/10.1029/2003GC000650

International audience [1] Thirteen laboratories from the USA and Europe participated in an intercomparison study of Mg/Ca and Sr/Ca measurements in foraminifera. The study included five planktonic species from surface sediments from different geographical regions and water depths. Each of the laboratories followed their own cleaning and analytical procedures and had no specific information about the samples. Analysis of solutions of known Mg/Ca and Sr/Ca ratios showed that the intralaboratory instrumental precision is better than 0.5% for both Mg/Ca and Sr/Ca measurements, regardless whether ICP-OES or ICP-MS is used. The interlaboratory precision on the analysis of standard solutions was about 1.5% and 0.9% for Mg/Ca and Sr/Ca measurements, respectively. These are equivalent to Mg/Ca-based temperature repeatability and reproducibility on the analysis of solutions of +/- 0.2 degreesC and +/- 0.5 degreesC, respectively. The analysis of foraminifera suggests an interlaboratory variance of about +/-8% (%RSD) for Mg/Ca measurements, which translates to reproducibility of about +/- 2 - 3 degreesC. The relatively large range in the reproducibility of foraminiferal analysis is primarily due to relatively poor intralaboratory repeatability (about +/- 1 - 2 degreesC) and a bias (about 1 degreesC) due to the application of different cleaning methods by different laboratories. Improving the consistency of cleaning methods among laboratories will, therefore, likely lead to better reproducibility. Even more importantly, the results of this study highlight the need for standards calibration among laboratories as a first step toward improving interlaboratory compatibility.