Stable oxygen isotope composition is biased by shell calcification intensity in planktonic Foraminifera

Weinkauf, Manuel; Groeneveld, Jeroen; Waniek, Joanna; Vennemann, Torsten; Martini, Rossana

doi:10.1002/essoar.10502627.1

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Title		Stable oxygen isotope composition is biased by shell calcification intensity in planktonic Foraminifera
Authors		Weinkauf, Manuel Groeneveld, Jeroen Waniek, Joanna Vennemann, Torsten Martini, Rossana
Year		2020
Description		18 p.
Abstract		Planktonic Foraminifera are widely used for environmental reconstructions through measurements of their shell's geochemical characteristics, including its stable oxygen and carbon isotope composition. Using these parameters as unbiased proxies requires a firm knowledge of all potential confounding factors influencing foraminiferal shell geochemistry. One such parameter is the shell calcification intensity (shell weight normalized for shell size) that may influence the shell delta 18O value either bioenergetically (by reducing energy available and required for equilibrium isotope fractionation during faster calcification) or kinetically (by influencing calcification depth through the shell's density contrast with seawater). Specimens from the Globigerinoides ruber/elongatus compound from a sediment trap in the North Atlantic have been used to quantify the influence of shell calcification intensity on shell delta 18O values. Shell calcification intensity was found to have a significant effect on the shell stable oxygen isotope composition in all species. Through model fitting, it is suggested that the effect size may be in a range of 1 to 2‰ (depending on species, depth migration, and local oceanographic conditions). We show that the confounding effect of shell calcification intensity on stable oxygen isotope composition can be of importance, depending on the anticipated precision of the derived reconstructions. A framework is provided to quantify this effect in future studies.
Keywords		Planktonic Foraminifera — Calcification — Stable oxygen isotope
Identifiers		DOI: 10.1002/essoar.10502627.1
Note		Soumis dans : Earth and Space Science Open Archive
Full text		Preprint (3.3 MB) - Free access
Structures		Faculté des sciences / Section des sciences de la Terre et de l'Environnement / Département des sciences de la Terre
Research group		Sedimentology, Biostratigraphy and Micropaleontology
Citation (ISO format)		WEINKAUF, Manuel et al. Stable oxygen isotope composition is biased by shell calcification intensity in planktonic Foraminifera. 2020. doi: 10.1002/essoar.10502627.1 https://archive-ouverte.unige.ch/unige:134085