Mapping Oxygen Isotopes in the North Pacific Ocean

Stable oxygen isotope (δ¹⁸O) and salinity measurements collected over the past 50 years have been used to create a gridded data set of seawater δ¹⁸O (LeGrande and Schmidt, 2006) that models characteristics of the water cycle. Paired δ¹⁸O and salinity measurements generally exhibit a linear relationship where the slope depends on regional conditions and is affected by river run-off and sea ice formation. The LeGrande and Schmidt (2006) gridded data set is broadly representative of the long-term mean of surface δ¹⁸O and cannot resolve near shore variability associated with seasonal δ¹⁸O and salinity variations. This project aims to contribute to the existing global gridded data set and create a geographical map of the Northern Pacific Ocean using seawater samples collected during the STEMSEAS May 2019 cruise (SKQ1913) from San Diego, CA to Seward, AK on the R/V Sikuliaq. This data is compared with GEOSECS/GEOTRACES data to determine the local δ¹⁸O-salinity relationship in contrast to the larger-scale global data set. This additional SKQ1913 data can be applied towards modeling climate change, characterizing ocean water masses and the water cycle.