Mesoscale Eddies Structure Mesopelagic Communities

• Published in: Frontiers in Marine Science
• Main Authors: Della Penna, Alice, Gaube, Peter
• Other Authors: Applied Physics Laboratory Seattle (APL-UW), University of Washington Seattle, 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 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)-Centre National de la Recherche Scientifique (CNRS), AD is grateful for the support of the Applied Physics Laboratory Science and Engineering Enrichment Development (SEED) fellowship and to the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement no. 749591. PG is grateful for the support of the NASA Physical Oceanography Program and NASA grant NNX16AH59G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: ACL; echosounder; fish; noise; deep scattering layers; eddies; mesoscale; naames; micronekton; bioacoustics; features; intermediate trophic levels; North Atlantic Aerosols; whales; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Elephant Seals; North Atlantic
• Online Access: https://hal.science/hal-02921207; https://hal.science/hal-02921207/document; https://hal.science/hal-02921207/file/fmars-07-00454.pdf; https://doi.org/10.3389/fmars.2020.00454

WOS:000551093900001 International audience Mesoscale eddies play a key role in structuring open ocean ecosystems, affecting the entire trophic web from primary producers to large pelagic predators including sharks and elephant seals. Recent advances in the tracking of pelagic predators have revealed that these animals forage in the mesopelagic and the depth and duration of their foraging dives are affected by the presence of eddies. The ways in which eddies impact the distribution of mesopelagic micronekton, however, remain largely unknown. During a multi-seasonal experiment we used a shipboard scientific echosounder transmitting at 38 kHz to observe the distribution of acoustic backscattering in the energetic mesoscale eddy field of the northwestern Atlantic. Observations were collected at 24 stations with 6 located in anticyclonic and 7 in cyclonic eddies. The sampled anticyclonic eddies are characterized by intense acoustic backscattering in the mesopelagic and changes in the intensity of acoustic backscattering layers match gradients of surface properties. Furthermore, mesopelagic daytime backscattering is positively correlated with sea level anomaly. These results suggest that anticyclonic eddies in the northwestern Atlantic impact the distribution of mesopelagic micronekton and may have the potential to locally enhance or structure spatially mesopelagic communities.