Coadic, R. and Bassinot, F. and Dissard, D. and Douville, E. and Greaves, M. J. and Michel, E. (2013) A core-top study of dissolution effect on B/Ca inGlobigerinoides sacculiferfrom the tropical Atlantic: Potential bias for paleo-reconstruction of seawater carbonate chemistry. Geochemistry, Geophysics, Geosystems, 14 (4). n/a-n/a. ISSN 15252027 DOI 10.1029/2012GC004296
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Abstract
It has been recently shown that B/Ca in planktonic foraminiferal calcite can be used as a proxy for seawater pH. Based on the study of surface sediments (multi-cores) retrieved along a depth transect on the Sierra Leone Rise (Eastern Equatorial Atlantic), we document the decrease of B/Ca and Mg/Ca of Globigerinoides sacculifer shells with increasing water depth and dissolution. This effect of dissolution on B/Ca may potentially represent a severe bias for paleo-pH reconstructions using this species. Samples of G. sacculifer were analyzed independently at two laboratories for B/Ca and Mg/Ca. Both sets of results show a systematic decrease of B/Ca and Mg/Ca along the depth transect, with an overall loss of ~14 mmol/mol (~15%) for B/Ca and of ~0.7 mmol/mol (~21%) for Mg/Ca between the shallowest (2640 m) and the deepest (4950 m) sites. Because of this dissolution effect, surface water pH reconstructed from B/Ca of G. sacculifer decreases by ~0.11 units between the shallowest site and the deepest site, a magnitude similar to the expected glacial/interglacial surface water pH changes.
| Item Type: | Article |
|---|---|
| Subjects: | 01 - Climate Change and Earth-Ocean Atmosphere Systems |
| Divisions: | 01 - Climate Change and Earth-Ocean Atmosphere Systems 08 - Green Open Access |
| Journal or Publication Title: | Geochemistry, Geophysics, Geosystems |
| Volume: | 14 |
| Page Range: | n/a-n/a |
| Identification Number: | 10.1029/2012GC004296 |
| Depositing User: | Sarah Humbert |
| Date Deposited: | 03 Jul 2014 17:21 |
| Last Modified: | 03 Jul 2014 17:21 |
| URI: | http://eprints.esc.cam.ac.uk/id/eprint/3078 |
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