Submesoscale ocean fronts act as biological hotspot for southern elephant seal

• Published in: Scientific Reports
• Main Authors: Siegelman, Lia, O’Toole, Malcolm, Flexas, Mar, Rivière, Pascal, Klein, Patrice
• Other Authors: Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Environmental Science and Engineering Pasadena (ESE), California Institute of Technology (CALTECH), The UWA Oceans Institute, ANR-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: ACL; ANTARCTIC CIRCUMPOLAR CURRENT; AREA-RESTRICTED SEARCH; FORAGING BEHAVIOR; MIROUNGA-LEONINA; MESOSCALE; PREDATOR; VARIABILITY; TURBULENCE; FEATURES; PASSAGE; geo; envir; Antarctic; Kerguelen; Kerguelen Islands; The Antarctic; Antarc*; Elephant Seal; Elephant Seals; Mirounga leonina; Southern Elephant Seal
• Online Access: https://doi.org/10.1038/s41598-019-42117-w; https://hal.archives-ouvertes.fr/hal-02874962/file/Siegelman_etal_SR_2019.pdf; https://hal.archives-ouvertes.fr/hal-02874962

International audience The area west of the Kerguelen Islands (20–70°E/45–60°S) is characterized by a weak mesoscale activity except for a standing meander region of the Antarctic Circumpolar Current (ACC) localized between 20 and 40°E. A unique bio-physical dataset at high-resolution collected by a southern elephant seal (Mirounga leonina) reveals a conspicuous increase in foraging activity at the standing meander site up to 5 times larger than during the rest of her three-month trip west of the Kerguelen Islands. Here, we propose a physical explanation for such high biological activity based on the study of small-scale fronts with scales of 5 to 20 km, also called submesoscales. The standing meander is associated with intensified frontal dynamics at submesoscale, not observed in the rest of the region. Results shed new light on the spatial distribution of submesoscale fronts in the under-sampled area west of the Kerguelen plateau and emphasize their importance for upper trophic levels. Despite that most elephant seals target foraging grounds east of the Kerguelen Plateau, our findings suggest that excursions to the west are not accidental, and may be explained by the recurrently elevated physical and biological activity of the site. As such, other standing meanders of the ACC may also act as biological hotspots where trophic interactions are stimulated by submesoscale turbulence.