Current Project

Spatiotemporal Variations of the δ18Osw-SSS relationship in the central Pacific Ocean over the 2015/16 El Niño

Marine carbonates, such as corals, are capable fo recording high-resolution data that are valuable for paleoclimate reconstructions. The stable oxygen isotope ratio δ18O of coral covaries with past SST with incredible accuracy at Kiritimati in the central Pacific (Grothe et al., 2019).

Neat, right? But we have to keep in mind that coral δ18O is the product of seawater δ18O and SST conbined. We can use Sr/Ca to separate the effect of SST, thus extracting seawater δ18O influences. In fact, that is what we've been using to resolve past seawater δ18O. Seawater δ18O has a linear relationship with sea-surface salinity (SSS), but this relationship has different slopes that is specific to the time and place of sampling (Conroy et al., 2017). So, when we attempt to use seawater δ18O to reconstruct paleosalinity, there's bound to be "paleosalinity errors", or discrepancies betweent the real salinity value at that time and location and the reconstructed salinity (Benway and Mix, 2004).

Linear relationship between 4 study sites across equatorial Pacific (Conroy et al. 2017)

To constrain ths relationship at finer spatial and temporal scales, we investigate how it changes throughout an ENSO cycle at the ENSO heart of impact: central and eastern Pacific. Our samples come from the NOAA 2016 El Niño Rapid Response Cruise and the P18 US GO-SHIP cruise.