Sensitivity of Nd isotopic composition in seawater to changes in Nd sources and paleoceanographic implications

Rempfer, J.; Stocker, T.F.; Joos, F.; Dutay, J.-C. (2012). Sensitivity of Nd isotopic composition in seawater to changes in Nd sources and paleoceanographic implications. Journal of geophysical research, 117(C12), C12010. American Geophysical Union 10.1029/2012JC008161

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It has been argued that past changes in the sources of Nd could hamper the use of the Nd isotopic composition (ϵNd) as a proxy for past changes in the overturning of deep water masses. Here we reconsider uncertainties associated with ϵNd in seawater due to potential regional to global scale changes in the sources of Nd by applying a modeling approach. For illustrative purposes we describe rather extreme changes in the magnitude of source fluxes, their isotopic composition or both. We find that the largest effects on ϵNd result from changes in the boundary source. Considerable changes also result from variations in the magnitude or ϵNd of dust and rivers but are largely constrained to depths shallower than 1 km, except if they occur in or upstream of regions where deep water masses are formed. From these results we conclude that changes in Nd sources have the potential to affect ϵNd. However, substantial changes are required to generate large-scale changes inϵNd in deep water that are similar in magnitude to those that have been reconstructed from sediment cores or result from changes in meridional overturning circulation in model experiments. Hence, it appears that a shift in ϵNdcomparable to glacial-interglacial variations is difficult to obtain by changes in Nd sources alone, but that more subtle variations can be caused by such changes and must be interpreted with caution.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Climate and Environmental Physics

UniBE Contributor:

Rempfer, Johannes; Stocker, Thomas and Joos, Fortunat

ISSN:

0148-0227

Publisher:

American Geophysical Union

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 14:44

Last Modified:

08 Oct 2015 07:34

Publisher DOI:

10.1029/2012JC008161

BORIS DOI:

10.7892/boris.18186

URI:

https://boris.unibe.ch/id/eprint/18186 (FactScience: 226052)

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