LA-MC-ICP-MS study of boron isotopes in individual planktonic foraminifera: A novel approach to obtain seasonal variability patterns

Mayk, Dennis and Fietzke, Jan and Anagnostou, Eleni and Paytan, Adina (2020) LA-MC-ICP-MS study of boron isotopes in individual planktonic foraminifera: A novel approach to obtain seasonal variability patterns. Chemical Geology, 531. p. 119351. ISSN 0009-2541 DOI https://doi.org/10.1016/j.chemgeo.2019.119351

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Abstract

Boron isotope (δ11B) analysis using bulk foraminifera samples is a widely used method to reconstruct paleo sea water pH conditions. Although, these analyses exhibit high analytical precision, short term information is lost due to the pooling of tests with distinct and diverse boron isotope signatures resulting in average values for the time interval encompassed in the sample. Here we present and assess the analysis of δ11B of individual foraminifera by means of Laser Ablation Multi-Collector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICP-MS) to obtain seasonal variability patterns and to test the limits of precision of LA-MC-ICP-MS on the planktonic foraminifera Orbulina universa. The results show that relative seasonal differences (of �11�) can be captured from either uncleaned or cleaned individual O. universa tests with an average precision of ±2.9� (2 SE). The δ11B variability among foraminifera representing the same season is on average 7.4� (2 SD) irrespective of cleaning state. With our approach, analyses on oxidatively cleaned O. universa do not require the use of a matrix matched standard to obtain B isotope values in the range of those expected for solution multi-specimen analyses. Our results are useful for considering the potential spread caused by foraminifera vital effects and for obtaining information of seasonal ranges of pH and possible bias related to seasonality hidden within conventional solution based δ11B analyses.

Item Type:	Article
Uncontrolled Keywords:	NILAREP; IA76
Subjects:	01 - Climate Change and Earth-Ocean Atmosphere Systems
Divisions:	01 - Climate Change and Earth-Ocean Atmosphere Systems
Journal or Publication Title:	Chemical Geology
Volume:	531
Page Range:	p. 119351
Identification Number:	https://doi.org/10.1016/j.chemgeo.2019.119351
Depositing User:	Dennis Mayk
Date Deposited:	09 Jul 2020 18:08
Last Modified:	09 Jul 2020 18:08
URI:	http://eprints.esc.cam.ac.uk/id/eprint/4527

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