Nd/Ca ratios in plankton-towed and core top foraminifera, supplement to: Martínez-Botí, Miquel Àngel; Vance, Derek; Mortyn, P Graham (2009): Nd/Ca ratios in plankton-towed and core top foraminifera: Confirmation of the water column acquisition of Nd. Geochemistry, Geophysics, Geosystems, 10(8), Q08018


Planktic foraminifera have been used as recorders of the neodymium (Nd) isotopic composition of seawater, although there is still controversy over the precise provenance of the Nd signal. We present an extensive, multispecific plankton tow Nd/Ca data set from several geographic locations (SE Atlantic, NE Atlantic, Norwegian Sea, and western Mediterranean), together with core top samples from the Mediterranean region. The range of Nd/Ca ratios in plankton-towed foraminifera, cleaned only of organic material, from all regions (0.01-0.7 µmol/mol), is similar to previously published analyses of sedimentary foraminifera cleaned using both oxidative and reductive steps, with distribution coefficients (Kd) ranging between 4 and 302. For the Mediterranean, where core top and plankton tow data are both available, the range for plankton tows (0.05-0.7 µmol/mol) is essentially identical to that for the core tops (0.1-0.5 µmol/mol). Readsorption of Nd during cleaning is ruled out by the fact that the plankton tow samples underwent only an oxidative cleaning process. We find a relationship between manganese (Mn) and Nd in plankton tow samples that is mirrored by a similar correlation in core top samples. This relationship suggests that Fe-Mn coatings are of negligible importance to the Nd budgets of foraminifera as the Nd/Mn ratio it implies is over an order of magnitude greater than that seen in other Fe-Mn oxide phases. Rather, since both plankton tows and core tops present a similar behavior, the Nd/Mn relationship must originate in the upper water column. The data are consistent with the acquisition of Nd and Mn from the water column by binding to organic material and the fact that intratest organic material is shielded from both aggressive cleaning and diagenetic processes. Collectively, the results help to explain two abiding puzzles about Nd in sedimentary planktic foraminifera: their high REE contents and the fact that they record a surface water Nd isotopic signal, regardless of the cleaning procedure used.

DOI https://doi.org/10.1594/PANGAEA.728595
Related Identifier https://doi.org/10.1029/2009GC002701
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.728595
Creator Martínez-Botí, Miquel Àngel; Vance, Derek; Mortyn, P Graham
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 2009
Rights Creative Commons Attribution 3.0 Unported
OpenAccess true
Language English
Resource Type Supplementary Collection of Datasets
Format application/zip
Size 8 datasets
Discipline Earth System Research
Spatial Coverage (-20.006W, -50.000S, 12.000E, 69.500N); Alboran Sea; Mediterranean Sea, Western Basin; Tirreno Sea; Western Mediterranean Sea; Norwegian-Greenland Sea
Temporal Coverage Begin 1996-02-13T14:45:00Z
Temporal Coverage End 2007-03-26T22:16:00Z