We investigated the Early Pliocene (5.3 to 3.6 million years ago) history of oceanic exchange across the Central American Seaway using a suite of geochemical measurements on planktonic foraminifera at Ocean Drilling Program Sites 165-999A (Caribbean Sea) and 1241 (Eastern Tropical North Pacific). Foraminifera-bound nitrogen isotopes were performed on Trilobatus sacculifer and combined samples of Globortalia menardii and Globortalia tumida, and measured via the persulfate-denitrifier methodology at Max Planck Institute for Chemistry. We also collated existing planktonic foraminifer oxygen isotope measurements and Mg/Ca in T. sacculifer from Sites 165-999A and 202-1241 (Haug et al., 2001; Groeneveld & Tiedemann, 2005; Steph et al., 2006). These data were used to calculate sea surface temperature and the oxygen isotope composition of seawater using PSU Solver (Thirumalai et al., 2016).

Funding for this project provided by the Max Planck Society.