Blar i forfatter "Mohamed, Mohamed Mahmoud Ezat Ahmed"

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    • Active Nordic Seas deep-water formation during the last glacial maximum 

      Larkin, Christina S.; Mohamed, Mohamed Mahmoud Ezat Ahmed; Roberts, Natalie L.; Bauch, Henning A.; Spielhagen, Robert F.; Noormets, Riko; Polyak, Leonid; Moreton, Steven G.; Rasmussen, Tine Lander; Sarnthein, Michael; Tipper, Edward T.; Piotrowski, Alex M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-24)
      The Nordic Seas are the primary location where the warm waters of the North Atlantic Current densify to form North Atlantic Deep Water, which plays a key part in the modern Atlantic Meridional Overturning Circulation. The formation of dense water in the Nordic Seas and Arctic Ocean and resulting ocean circulation changes were probably driven by and contributed to the regional and global climate of ...

    • Large-scale culturing of Neogloboquadrina pachyderma, its growth in, and tolerance of, variable environmental conditions 

      Westgård, Adele; Mohamed, Mohamed Mahmoud Ezat Ahmed; Chalk, Tom; Chierici, Melissa; Foster, Gavin L.; Meilland, Julie (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-09)
      The planktic foraminifera Neogloboquadrina pachyderma is a calcifying marine protist and the dominant planktic foraminifera species in the polar oceans, making it a key species in marine polar ecosystems. The calcium carbonate shells of foraminifera are widely used in palaeoclimate studies because their chemical composition reflects the seawater conditions in which they grow. This species provides ...

    • Sea ice-ocean coupling during Heinrich Stadials in the Atlantic–Arctic gateway 

      el Bani Altuna, Naima; Mohamed, Mohamed Mahmoud Ezat Ahmed; Smik, Lukas; Muschitiello, Francesco; Belt, Simon T.; Knies, Jochen Manfred; Rasmussen, Tine Lander (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-11)
      The variability of Arctic sea-ice during abrupt stadial-interstadial shifts in the last glacial period remain poorly understood. Here, we investigated the millennial-scale relationship, with a focus on Heinrich Stadials (HS), between sea-ice cover and bottom water temperature (BWT) during Marine Isotope Stages (MIS) 3 and 2 (64–13 ka) in the Fram Strait using new molecular sea ice biomarker data and ...

    • Spatial Changes in Gas Transport and Sediment Stiffness Influenced by Regional Stress: Observations From Piezometer Data Along Vestnesa Ridge, Eastern Fram Strait 

      Plaza-Faverola, Andreia; Sultan, Nabil; Lucchi, Renata Giulia; El bani Altuna, Naima; Ramachandran, Hariharan; Singhroha, Sunny; Cooke, Frances Ann; Vadakkepuliyambatta, Sunil; Mohamed, Mohamed Mahmoud Ezat Ahmed; Rasmussen, Tine Lander (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-25)
      Gas transport through sediments to the seabed and seepage occurs via advection through pores, faults, and fractures, and as solubility driven gas diffusion. The pore pressure gradient is a key factor in these processes. Yet, in situ measurements for quantitative studies of fluid dynamics and sediment deformation in deep ocean environments remain scarce. In this study, we integrate piezometer data, ...

    • Uncovering hidden structures: previously undescribed pseudopodia and ectoplasmic structures in planktonic foraminifera 

      Greco, Mattia; Westgård, Adele; Sykes, Freya Elizabeth; Mohamed, Mohamed Mahmoud Ezat Ahmed; Meilland, Julie (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-05)
      The trophic strategies of cold-water planktonic foraminifera are not well understood due to the challenge of culturing them in polar conditions. Here, we identify previously unknown ectoplasmic and cytoplasmic projections in three species of planktonic foraminifera thriving in polar and subpolar marine environments: Globigerina bulloides, Neogloboquadrina incompta and Neogloboquadrina pachyderma. ...