<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE article PUBLIC "-//NLM//DTD Journal Publishing DTD v3.0 20080202//EN" "https://jats.nlm.nih.gov/nlm-dtd/publishing/3.0/journalpublishing3.dtd">
<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" article-type="research-article" specific-use="SMUR" dtd-version="3.0" xml:lang="en">
<front>
<journal-meta>
<journal-id journal-id-type="publisher">EGUsphere</journal-id>
<journal-title-group>
<journal-title>EGUsphere</journal-title>
<abbrev-journal-title abbrev-type="publisher">EGUsphere</abbrev-journal-title>
<abbrev-journal-title abbrev-type="nlm-ta">EGUsphere</abbrev-journal-title>
</journal-title-group>
<publisher><publisher-name>Copernicus Publications</publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/egusphere-2026-6242</article-id>
<title-group>
<article-title>Benthic habitat zonation across oceanographic gradients and seafloor morphology from the mesophotic to the deep zone of the Gulf of Aqaba and the Northern Red Sea</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Marchese</surname>
<given-names>Fabio</given-names>
<ext-link>https://orcid.org/0000-0001-8384-3019</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Chimienti</surname>
<given-names>Giovanni</given-names>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Ouhssain</surname>
<given-names>Mustapha</given-names>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Terraneo</surname>
<given-names>Tullia Isotta</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Ezeta Watts</surname>
<given-names>Marta Andrea</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Vicario</surname>
<given-names>Silvia</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Macrina</surname>
<given-names>Laura</given-names>
<ext-link>https://orcid.org/0000-0003-1863-0134</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Purkis</surname>
<given-names>Sam J.</given-names>
</name>
<xref ref-type="aff" rid="aff5">
<sup>5</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Pieribone</surname>
<given-names>Vincent</given-names>
</name>
<xref ref-type="aff" rid="aff6">
<sup>6</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Rodrigue</surname>
<given-names>Mattie</given-names>
</name>
<xref ref-type="aff" rid="aff6">
<sup>6</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Craig</surname>
<given-names>Andrew</given-names>
</name>
<xref ref-type="aff" rid="aff6">
<sup>6</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Eweida</surname>
<given-names>Ameer Abdullah</given-names>
</name>
<xref ref-type="aff" rid="aff7">
<sup>7</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Benzoni</surname>
<given-names>Francesca</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, Bari, Italy</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Center for Remote Sensing Applications (CRSA), Mohammed VI Polytechnic University (UM6P), Ben Guerir, Morocco</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>Marine Science Program, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia</addr-line>
</aff>
<aff id="aff5">
<label>5</label>
<addr-line>Department of Marine Geosciences, Rosenstiel School of Marine, Atmospheric, and Earth Science, University of Miami, Miami, U.S.A.</addr-line>
</aff>
<aff id="aff6">
<label>6</label>
<addr-line>OceanX, New York, U.S.A.</addr-line>
</aff>
<aff id="aff7">
<label>7</label>
<addr-line>Red Sea Authority, Riyadh, Kingdom of Saudi Arabia</addr-line>
</aff>
<pub-date pub-type="epub">
<day>22</day>
<month>10</month>
<year>2026</year>
</pub-date>
<volume>2026</volume>
<fpage>1</fpage>
<lpage>54</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2026 Fabio Marchese et al.</copyright-statement>
<copyright-year>2026</copyright-year>
<license license-type="open-access">
<license-p>This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit <ext-link ext-link-type="uri"  xlink:href="https://creativecommons.org/licenses/by/4.0/">https://creativecommons.org/licenses/by/4.0/</ext-link></license-p>
</license>
</permissions>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2026-6242/">This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-6242/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2026-6242/egusphere-2026-6242.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-6242/egusphere-2026-6242.pdf</self-uri>
<abstract>
<p>The Gulf of Aqaba and Northern Red Sea are among the least explored basins of the Indo-Pacific region. There, while the shallow Red Sea coastal benthic habitats have been extensively characterised and their zonation in relation to environmental factors described, mesophotic and deep-sea habitats remain comparatively poorly characterised. These habitats develop in a water column that, unlike in most of the global ocean, remains warm (~21 &amp;deg;C) and hypersaline (~40.6) below the pycnocline. In this context, we present the first regional assessment of benthic habitat zonation from the mesophotic to the deep zone (70&amp;ndash;700 m) along the Saudi Arabian margin of the Gulf of Aqaba and Northern Red Sea. Using high-resolution multibeam bathymetry, CTD profiles, and over 135 hours of high-definition footage from underwater vehicles, we developed a hierarchical habitat classification, integrating physiography, substrate, terrain analysis, and visually identified biota. Fourteen distinct benthic habitats were identified, including crustose coralline algae- and rariphotic coral-dominated bioconstructions, octocoral-dominated assemblages and deep scleractinian coral frameworks. Oceanographic parameters (temperature, salinity, oxygen concentration) and seafloor morphology were both associated with habitat spatial distribution across the two basins. Multivariate analyses revealed a consistent vertical zonation, with three ecological breaks at approximately 100, 120, and 160&amp;ndash;180 m depth, delineating four successive zones from the lower mesophotic to the deep azooxanthellate assemblages. This work fills a major knowledge gap for the Red Sea&apos;s deep-water ecosystems, providing a critical baseline to support future monitoring, conservation, and management strategies in a rapidly developing region.</p>
</abstract>
<counts><page-count count="54"/></counts>
</article-meta>
</front>
<body/>
<back>
</back>
</article>