Isotopic Characterization of Water Masses in the Southeast Pacific Region: Paleoceanographic Implications

Dharma Reyes-Macaya*, Babette Hoogakker, Gema Martínez-Méndez, Pedro J. Llanillo, Patricia Grasse, Mahyar Mohtadi, Alan Mix, Melanie J. Leng, Ulrich Struck, Daniel C. McCorkle, Macarena Troncoso, Eugenia M. Gayo, Carina B. Lange, Laura Farias, Wilson Carhuapoma, Michelle Graco, Marcela Cornejo-D’Ottone, Ricardo De Pol Holz, Camila Fernandez, Diego NarvaezCristian A. Vargas, Francisco García-Araya, Dierk Hebbeln

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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Abstract

In this study, we used stable isotopes of oxygen (δ18O), deuterium (δD), and dissolved inorganic carbon (δ13CDIC) in combination with temperature, salinity, oxygen, and nutrient concentrations to characterize the coastal (71°–78°W) and an oceanic (82°–98°W) water masses (SAAW—Subantarctic Surface Water; STW—Subtropical Water; ESSW—Equatorial Subsurface water; AAIW—Antarctic Intermediate Water; PDW—Pacific Deep Water) of the Southeast Pacific (SEP). The results show that δ18O and δD can be used to differentiate between SAAW-STW, SAAW-ESSW, and ESSW-AAIW. δ13CDIC signatures can be used to differentiate between STW-ESSW (oceanic section), SAAW-ESSW, ESSW-AAIW, and AAIW-PDW. Compared with the oceanic section, our new coastal section highlights differences in both the chemistry and geometry of water masses above 1,000 m. Previous paleoceanographic studies using marine sediments from the SEP continental margin used the present-day hydrological oceanic transect to compare against, as the coastal section was not sufficiently characterized. We suggest that our new results of the coastal section should be used for past characterizations of the SEP water masses that are usually based on continental margin sediment samples.

Original languageEnglish
Article numbere2021JC017525
JournalJournal of Geophysical Research: Oceans
Volume127
Issue number1
Early online date23 Dec 2021
DOIs
Publication statusPublished - Jan 2022

Keywords

  • carbon stable isotopes in dissolved inorganic carbon
  • oxygen and deuterium stable isotopes in seawater
  • paleoceanography proxies
  • Southeast Pacific
  • water mass distribution

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Oceanography

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