Thermal small steps staircase and layer migration in the Atlantis II Deep, Red Sea

  • Alaa M. A. AlbarakatiEmail author
  • Daniel F. McGinnis
  • Fazal Ahmad
  • Peter Linke
  • Marcus Dengler
  • Peter Feldens
  • Mark Schmidt
  • Radwan Al-Farawati
Original Paper


Atlantis II Deep, a submarine basin of the Red Sea, is noteworthy because of its hydrothermally active brine pools. High-resolution temperature records from Poseidon Cruise during February 2011 revealed small steps thermal staircase in the lower transition zone from ≈2002 to 2008/2009 m depth at stations. Four vertically well-mixed convective layers, lower convective layer (LCL) and upper convective layers (UCL1–3), separated by high-temperature gradients at the interfaces were observed. The temperature of the layers UCL1–3 has dropped between 2008 and 2011. The top of UCL3 extends to about 2008/2009 m at stations and its average thickness has increased from 3.3 ± 0.5 m in 1992 to 7 m in 2011, whereas the thickness of layers UCL1–2 has decreased from 25.2 ± 0.3 m to 19.8 m and from 16.4 ± 0.5 m to 14.7 m, respectively, during this time. The upward buoyancy flux is 0.032 to 0.038 × 10−7 m2 s−3 which gives migration speed of UCL3 layer from 0.1 to 0.12 m year−1. With this speed, the thermal staircase ≈6 m thick will merge with UCL3 in 50 to 60 years increasing the thickness from 7 m to nearly 13 m.


Atlantis II Deep Red Sea Double-diffusive layering Thermal staircase merger 



The Jeddah Transect Project, a collaboration between King Abdulaziz University and Helmholtz Center for Ocean Research GEOMAR, was funded by King Abdulziz University (KAU) Jeddah, Saudi Arabia, under grant no. (T-065/430-DSR). The authors acknowledge with thanks KAU technical and financial support. The patience and cooperation of the captain and crew of R/V Poseidon in collecting the data are highly appreciated.


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Copyright information

© Saudi Society for Geosciences 2016

Authors and Affiliations

  • Alaa M. A. Albarakati
    • 1
    Email author
  • Daniel F. McGinnis
    • 2
  • Fazal Ahmad
    • 1
  • Peter Linke
    • 3
  • Marcus Dengler
    • 3
  • Peter Feldens
    • 4
  • Mark Schmidt
    • 3
  • Radwan Al-Farawati
    • 1
  1. 1.Faculty of Marine SciencesKing Abdulaziz UniversityJeddahSaudi Arabia
  2. 2.Institute F.-A. Forel, Faculty of ScienceUniversity of GenevaGenevaSwitzerland
  3. 3.GEOMAR | Helmholtz Centre for Ocean Research KielKielGermany
  4. 4.Leibniz Institute for Baltic Sea ResearchWarnemündeGermany

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