Environmental Controls on the Geochemistry of emGloborotalia truncatulinoides/em in the Gulf of Mexico: Implications for Paleoceanographic Reconstructions

Caitlin E. Reynolds, Julie N. Richey, Jennifer S. Fehrenbacher, Brad E. Rosenheim, Howard J. Spero

Research output: Contribution to journalArticlepeer-review

Abstract

<p> <p id="x-x-sp0075"> Modern observations of planktic foraminifera from <a title="Learn more about sediment trap from ScienceDirect's AI-generated Topic Pages"> sediment trap </a> studies help to constrain the regional ecology of paleoceanographically valuable species. Results from a weekly-resolved sediment trap time series (2008&ndash;2014) in the northern <a title="Learn more about Gulf of Mexico from ScienceDirect's AI-generated Topic Pages"> Gulf of Mexico </a> demonstrate that 92% of <em> Globorotalia truncatulinoides </em> 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 <em> G. truncatulinoides </em> tests to investigate differences in the elemental (Mg/Ca) and <a title="Learn more about isotopic composition from ScienceDirect's AI-generated Topic Pages"> isotopic composition </a> (&delta; <sup> 18 </sup> O and &delta; <sup> 13 </sup> C) of the encrusted and non-encrusted ontogenetic forms of <em> G. truncatulinoides </em> , and to estimate their calcification depth in the northern Gulf of Mexico. We estimate that non-encrusted and encrusted <em> G. truncatulinoides </em> have mean calcification depths of 66 &plusmn; 9 m and 379 &plusmn; 76 m, respectively. We validate the Mg/Ca-calcification temperature relationship for <em> G. truncatulinoides </em> and demonstrate that the &delta; <sup> 18 </sup> 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 <em> G. truncatulinoides </em> for down core paleoceanographic studies. </p></p>
Original languageAmerican English
JournalMarine Micropaleontology
Volume142
DOIs
StatePublished - Jan 1 2018

Keywords

  • Globorotalia truncatulinoides
  • Gulf of Mexico
  • Laser ablation
  • Mg/Ca
  • Planktic foraminifer
  • Sediment trap

Disciplines

  • Life Sciences

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