Characterizing seawater oxygen isotopic variability in a regional ocean modeling framework: Implications for coral proxy records

A new ocean modeling approach reveals significant local variability in seawater oxygen isotopic ratios (δ18O) that affects coral proxy records, particularly at Palmyra Atoll. The study found that tropical instability waves (TIWs) generate large temperature and δ18O excursions, introducing nonlinear processes that alter the relationship between salinity and seawater δ18O. These findings highlight the importance of considering mesoscale oceanographic features when interpreting coral δ18O data for reconstructing climate phenomena like El Niño–Southern Oscillation (ENSO). The research used a high-resolution regional ocean model to simulate δ18O variations over three decades, providing critical insights into the physical context of reef environments that can improve paleoclimate reconstructions.

Stevenson, S., Powell, B. S., Merrifield, M. A., Cobb, K. M., Nusbaumer, J., & Noone, D. (2015). Characterizing seawater oxygen isotopic variability in a regional ocean modeling framework: Implications for coral proxy records. Paleoceanography, 30(11), 1573–1593. Portico. https://doi.org/10.1002/2015pa002824