Characterizing the stable oxygen isotopic composition of the southeast Indian Ocean

• Published in: Marine chemistry 2024-05, Vol.262, p.104397, Article 104397
• Main Authors: Glaubke, Ryan H., Wagner, Amy J., Sikes, Elisabeth L.
• Format: Article
• Language: English
• Subjects: Hydroclimate; Oxygen-18; Southeast Indian Ocean; Stable oxygen isotopes; Water mass mixing
• ISSN: 0304-4203; 1872-7581
• DOI: 10.1016/j.marchem.2024.104397

New seawater stable oxygen isotope (δ18O) samples were collected from the southeast Indian Ocean as part of the Coring to Reconstruct Ocean Circulation and Carbon dioxide Across 2 Seas (CROCCA-2S) expedition in November – December of 2018. These data fill a gap in the δ18O sampling coverage of the southern Indian basin, providing new insights into the hydrologic and oceanographic processes influencing the δ18O distribution of the region and its relationship to salinity in the upper ocean. Our surface ocean data ( ∼1500 m), we observe a notable 0.87‰ spread in δ18O. This variability may represent interactions between distinct deep water masses in the region, although additional data are needed to confirm. Overall, our data provide a new look at the hydrography and isotopic chemistry of the southeast Indian Ocean, emphasizing the impact of the region's mesoscale eddy field and its interconnectivity with neighboring basins. •New seawater δ18O and hydrographic observations from the southeast Indian Ocean.•Surface δ18O – salinity relationships reflect regional hydroclimate and ocean mixing.•δ18O and salinity illustrate water mass connectivity across Indo-Australian basin.