Unraveling Salinity Extreme Events in Coastal Environments: A Winter Focus on the Bay of Brest

Type Article
Date 2021-07
Language English
Author(s) Poppeschi ColineORCID1, Charria GuillaumeORCID1, Goberville Eric2, Rimmelin-Maury Peggy3, Barrier Nicolas4, Petton SebastienORCID5, Unterberger Maximilian1, Grossteffan Emilie3, Repecaud Michel6, Quemener LoicORCID6, Theetten SebastienORCID1, Le Roux Jean-FrancoisORCID1, Treguer Paul7
Affiliation(s) 1 : Laboratoire d’Océanographie Physique et Spatiale (LOPS), IUEM, CNRS, IRD, Ifremer, Université de Brest, Brest, France
2 : Unité Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Muséum National d’Histoire Naturelle, CNRS, IRD, Sorbonne Université, Université de Caen Normandie, Université des Antilles, Paris, France
3 : UMS 3113, OSU-Institut Universitaire Européen de la Mer (IUEM), Plouzané, France
4 : CNRS, Ifremer, IRD, MARBEC, University of Montpellier, Sète, France
5 : CNRS, IRD, LEMAR, Ifremer, Université de Brest, Argenton, France
6 : REM/RDT/DCM, Ifremer, Centre de Brest, Plouzané, France
7 : CNRS, IRD, Ifremer, Institut Universitaire Européen de la Mer, LEMAR, Université de Brest, Plouzané, France
Source Frontiers In Marine Science (2296-7745) (Frontiers Media), 2021-07 , Vol. 8 , P. 705403 (14p.)
DOI 10.3389/fmars.2021.705403
Keyword(s) Bay of Brest, salinity, river plume, atmospheric weather regimes, extreme events
Abstract

Extreme weather events affect coastal marine ecosystems. The increase in intensity and occurrence of such events drive modifications in coastal hydrology and hydrodynamics. Here, focusing on the winter period (from December to March), we investigated multi-decade (2000–2018) changes in the hydrological properties of the Bay of Brest (French Atlantic coast) as an example of the response of a semi-enclosed bay to extreme weather episodes and large-scale atmospheric circulation patterns. The relationships between extreme weather events and severe low salinity conditions (as a proxy for changes in water density) were investigated using high-frequency in situ observations and high-resolution numerical simulations. The identification of intense episodes was based on the timing, duration, and annual occurrence of extreme events. By examining the interannual variability of extreme low salinity events, we detect a patent influence of local and regional weather conditions on atmospheric and oceanic circulation patterns, precipitation, and river runoff. We revealed that low salinity events in Brittany were controlled by large-scale forcings: they prevailed during the positive phase of the North Atlantic Oscillation and periods of low occurrences of the Atlantic Ridge weather regime. The increase in severe storms observed in western France since 2010 has led to a doubling of the occurrence and duration of extreme low salinity events in Brittany.

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Poppeschi Coline, Charria Guillaume, Goberville Eric, Rimmelin-Maury Peggy, Barrier Nicolas, Petton Sebastien, Unterberger Maximilian, Grossteffan Emilie, Repecaud Michel, Quemener Loic, Theetten Sebastien, Le Roux Jean-Francois, Treguer Paul (2021). Unraveling Salinity Extreme Events in Coastal Environments: A Winter Focus on the Bay of Brest. Frontiers In Marine Science, 8, 705403 (14p.). Publisher's official version : https://doi.org/10.3389/fmars.2021.705403 , Open Access version : https://archimer.ifremer.fr/doc/00706/81774/