Sr/Ca and Cd/Ca ratios of benthic foraminifera in surface deep-sea sediments, supplement to: Elderfield, Henry; Bertram, Caroline J; Erez, Jonathan (1996): A biomineralization model for the incorporation of trace elements into foraminiferal calcium carbonate. Earth and Planetary Science Letters, 142(3-4), 409-423

Measurements of Sr/Ca of benthic foraminifera show a linear decrease with water depth which is superimposed upon significant variability identified by analyses of individual foraminifera. New data for Cd/Ca support previous work in defining a contrast between waters shallower and deeper than ~2500 m...

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Bibliographic Details
Main Authors: Elderfield, Henry, Bertram, Caroline J, Erez, Jonathan
Format: Article in Journal/Newspaper
Language:English
Published: PANGAEA - Data Publisher for Earth & Environmental Science 1996
Subjects:
Kasten corer
Box corer
Piston corer
D184
NEAP
V22
V27
Discovery 1962
Charles Darwin
Vema
Biogeochemical Ocean Flux Study BOFS
Joint Global Ocean Flux Study JGOFS
Planktonic foraminifera
Online Access:https://dx.doi.org/10.1594/pangaea.708384
https://doi.pangaea.de/10.1594/PANGAEA.708384
Description
Summary:Measurements of Sr/Ca of benthic foraminifera show a linear decrease with water depth which is superimposed upon significant variability identified by analyses of individual foraminifera. New data for Cd/Ca support previous work in defining a contrast between waters shallower and deeper than ~2500 m. Measured element partition coefficients in foraminiferal calcium carbonate relative to sea water (D) have been described by means of a one-box model in which elements are extracted by Rayleigh distillation from a biomineralization reservoir that serves for calcification with a constant fractionation factor (alpha), such that D = (1 - f**alpha)/(l - f), where f is the proportion of Ca remaining after precipitation. A modification to the model recognises differences in element speciation. The model is consistent with differences between D[Sr], D[Ba], and D[Cd] in benthic but not planktonic foraminifera. Depth variations in D for Sr and Ba are consistent with the model, as are differences in depth variation of D[Cd] in calcitic and aragonitic benthic foraminifera. The shallower depth variations may reflect increasing calcification rates with increasing water depth to an optimum of about 2500 m. Observations of unusually lower DCd for some deep waters, not accompanied by similar [Sr], or D[Ba] may be because of dissolution or a calcification response to a lower carbonate saturation state.

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