Exploring foraminiferal Sr/Ca as a new carbonate system proxy
Abstract
In present day paleoclimate research one of the most pressing challenges is the reconstruction of atmospheric CO2 concentrations. A variety of proxies for several components of the marine inorganic carbon system have been developed in this context (e.g. B isotopes, B/Ca, U/Ca) to allow reconstruction of past seawater pH, HCO3- and CO32- and thereby facilitate estimates of past atmospheric pCO2. Based on culture experiments using the benthic foraminifera Ammonia sp. we describe a positive correlation between Sr/Ca and the carbonate system, namely DIC/bicarbonate ion concentration. Foraminiferal Sr/Ca ratios provide potentially additional constraints on the carbonate system proxy, because the analysis of foraminiferal carbonate Sr/Ca is straightforward and not easily contaminated. Applying our calibration to a published dataset of paleo-Sr/Ca suggests the validity of Sr/Ca as a carbonate system proxy. Furthermore, we explore how our data can be used to advance conceptual understanding of the foraminiferal biomineralization mechanism.
- Publication:
-
Geochimica et Cosmochimica Acta
- Pub Date:
- April 2017
- DOI:
- Bibcode:
- 2017GeCoA.202..374K
- Keywords:
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- C-system;
- Proxies;
- Ammonia;
- Strontium;
- DIC;
- Foraminifera;
- Sr/Ca;
- Calibration