Julie N. Richey
Jennifer S. Fehrenbacher
Brad E. Rosenheim
Howard J. Spero
Caitlin E. Reynolds
2018
<p><span>Modern observations of planktic foraminifera from sediment trap studies help to constrain the regional ecology of paleoceanographically valuable species. Results from a weekly-resolved sediment trap time series (2008–2014) in the northern Gulf of Mexico demonstrate that 92% of </span><i>Globorotalia truncatulinoides</i><span> flux occurs in winter (January, February, and March), and that encrusted and non-encrusted individuals represent calcification in distinct depth habitats. We use individual foraminiferal analysis (IFA) of </span><i>G. truncatulinoides</i><span> tests to investigate differences in the elemental (Mg/Ca) and isotopic composition (δ</span><sup>18</sup><span>O and δ</span><sup>13</sup><span>C) of the encrusted and non-encrusted ontogenetic forms of </span><i>G. truncatulinoides</i><span>, and to estimate their calcification depth in the northern Gulf of Mexico. We estimate that non-encrusted and encrusted </span><i>G. truncatulinoides</i><span> have mean calcification depths of 66 ± 9 m and 379 ± 76 m, respectively. We validate the Mg/Ca-calcification temperature relationship for </span><i>G. truncatulinoides</i><span> and demonstrate that the δ</span><sup>18</sup><span>O and Mg/Ca of the non-encrusted form is a suitable proxy for winter surface mixed layer conditions in the Gulf of Mexico. Care should be taken not to combine encrusted and non-encrusted individuals of </span><i>G. truncatulinoides</i><span> for down core paleoceanographic studies.</span></p>
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10.1016/j.marmicro.2018.05.006
en
Elsevier
Environmental controls on the geochemistry of Globorotalia truncatulinoides in the Gulf of Mexico: Implications for paleoceanographic reconstructions
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