Environmental Controls on the Geochemistry of Globorotalia truncatulinoides in the Gulf of Mexico: Implications for Paleoceanographic Reconstructions

Authors

Caitlin E. Reynolds, U.S. Geological Survey, St. Petersburg, FL 33701, USA
Julie N. Richey, U.S. Geological Survey, St. Petersburg, FL 33701, USA
Jennifer S. Fehrenbacher, Oregon State University
Brad E. Rosenheim, University of South FloridaFollow
Howard J. Spero, University of California Davis

Document Type

Article

Publication Date

2018

Keywords

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

Digital Object Identifier (DOI)

https://doi.org/10.1016/j.marmicro.2018.05.006

Abstract

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 Globorotalia truncatulinoides 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 G. truncatulinoides tests to investigate differences in the elemental (Mg/Ca) and isotopic composition (δ¹⁸O and δ¹³C) of the encrusted and non-encrusted ontogenetic forms of G. truncatulinoides, and to estimate their calcification depth in the northern Gulf of Mexico. We estimate that non-encrusted and encrusted G. truncatulinoides have mean calcification depths of 66 ± 9 m and 379 ± 76 m, respectively. We validate the Mg/Ca-calcification temperature relationship for G. truncatulinoides and demonstrate that the δ¹⁸O 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 G. truncatulinoides for down core paleoceanographic studies.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

Marine Micropaleontology, v. 142, p. 92-104

Scholar Commons Citation

Reynolds, Caitlin E.; Richey, Julie N.; Fehrenbacher, Jennifer S.; Rosenheim, Brad E.; and Spero, Howard J., "Environmental Controls on the Geochemistry of Globorotalia truncatulinoides in the Gulf of Mexico: Implications for Paleoceanographic Reconstructions" (2018). Marine Science Faculty Publications. 2440.
https://digitalcommons.usf.edu/msc_facpub/2440