Drivers of Oxygen Consumption in the Northern Gulf of Mexico Hypoxic Waters—A Stable Carbon Isotope Perspective

Details

• Journal Title:
  Geophysical Research Letters
• Personal Author:
  Wang, Hongjie ; Hu, Xinping ; Rabalais, Nancy N. ; Brandes, Jay
• NOAA Program & Office:
  NOS (National Ocean Service) ; NCCOS (National Centers for Coastal Ocean Science)
• Description:
  We examined the stable carbon isotopic composition of remineralized organic carbon (δ13COCx) in the northern Gulf of Mexico (nGoM) using incubations (sediment and water) and a three-end-member mixing model. δ13COCx in incubating sediments was −18.1‰ ± 1.3‰, and δ13COCx in incubating near-surface and near-bottom waters varied with salinity, ranging from −30.4‰ to −16.2‰ from brackish water to full-strength Gulf water. The average δ13COCx was −18.6‰ ± 1.8‰ at salinity >23. A three-end-member mixing model based on a multiyear data set collected in previous summer hypoxia cruises (2011, 2012, 2014, 2015, and 2016) suggested that δ13COCx in near-bottom waters across the nGoM (5–50 m) was −18.1‰ ± 0.6‰. The close agreement of δ13COCx obtained from the three independent approaches, that is, incubations of water column, surface sediments, and mixing model, suggests that 13C-enriched organic matter of marine origin played the dominant role in near-bottom water and benthic oxygen consumption in the nGoM shelf in summer.
• Keywords:
  Hypoxia
• Source:
  Geophysical Research Letters, 45(19)
• DOI:
  https://doi.org/10.1029/2018gl078571
• ISSN:
  0094-8276 ; 1944-8007
• Format:
  PDF
• Publisher:
  American Geophysical Union (AGU)
• Document Type:
  Journal Article
• Funding:
  Grant no. NA09NOS4780204
• Place as Subject:
  Mexico, Gulf of
• Rights Information:
  Other
• Compliance:
  CHORUS
• Main Document Checksum:
  urn:sha256:d11d7db310f591f975e0b1f335de9dceb9a983499c2086746638868febac69ec
• Download URL:
  https://repository.library.noaa.gov/view/noaa/49929/noaa_49929_DS1.pdf
• File Type:
  [PDF - 1.62 MB ]