Comment on egusphere-2026-1925

Abstract

Abstract. Hypersaline overflows from Marginal seas contribute to global ocean circulation and climate variability. The Persian/Arabian Gulf (P/AG) contributes dense, saline, oxygenated deep outflow into the Arabian Sea’s Oxygen Minimum Zone (OMZ). Here, we present high-resolution hydrographic mapping of the UAE-Oman margin in the northwestern Arabian Sea, integrating CTD profiles, multibeam bathymetry and ROV imagery. The P/AG outflow forms a thin bottom-attached layer that thickens dramatically over the rough, irregular seafloor of the unstable shelf, where dilution and loss of bottom contact occur. Near-bottom salinity, oxygen, and pH decrease systematically downstream in association with enhanced mixing. Distinct benthic assemblages coincide with attached versus detached flow sectors, consistent with differing near-bed hydrodynamic regimes. These observations indicate that bathymetric roughness controls the near-field transformation of the outflow. Because outflow density depends on Gulf warming and evaporation, modest climatic shifts may alter detachment depth, pathway geometry, and intermediate-depth ventilation of the Arabian Sea OMZ.

Authors 5

1. Ahmed J. Abdelmaksoud corresponding

   Khalifa University of Science and Technology

   Affiliation as printed

   Earth Sciences Department, Khalifa University, 127788, Abu Dhabi, United Arab Emirates

2. Aisha Al-Suwaidi

   Khalifa University of Science and Technology

   Affiliation as printed

   Earth Sciences Department, Khalifa University, 127788, Abu Dhabi, United Arab Emirates

3. Gerd Bruss

   Sultan Qaboos University

   Affiliation as printed

   Department of Marine Science and Fisheries, Sultan Qaboos University, Muscat, Oman

4. Kaveh Samimi‐Namin Aachen Marine Evolution and Ecology Group Naturalis Biodiversity Center

   Naturalis Biodiversity Center · Natural History Museum · University of Oxford

   Affiliation as printed

   Department of Biology, University of Oxford, Oxford, OX1 3SZ, UK

   Marine Evolution and Ecology Group, Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA, Leiden, The Netherlands

   Natural History Museum, Cromwell Road, London, SW7 5BD, UK

5. Mohammed Y. Ali

   Khalifa University of Science and Technology

   Affiliation as printed

   Earth Sciences Department, Khalifa University, 127788, Abu Dhabi, United Arab Emirates