@article{fdi:010092866,
  title = {{V}ariability of bottom dissolved oxygen on the southern {S}enegalese shelf at intraseasonal to interannual time scales using a modelling approach},
  author = {{T}all, {A}. {W}. and {E}chevin, {V}incent and {C}apet, {X}. and {M}achu, {E}ric},
  editor = {},
  language = {{ENG}},
  abstract = {{R}ecent in-situ measurements on the west {A}frican continental shelf have shown that the bottom waters undergo episodic hypoxia and even anoxia. {I}n this study, we investigate the variability of bottom dissolved oxygen ({DO}) over the southern {S}enegalese shelf at seasonal, intraseasonal and interannual time scales over the period 2015-2019 using a high-resolution (2 km) regional coupled dynamical-biogeochemical model. {T}he model is forced by daily winds to represent synoptic variability during the upwelling-favourable cold season ({N}ovember- {M}ay). {N}ear-bottom {DO} evaluation using data from the {M}elax mooring located over the mid shelf indicates that the model represents well the seasonal and intraseasonal variability. {A} bottom {DO} budget shows that advection of deep, low-oxygenated waters over the shelf edge during the upwelling season generates a {DO} loss, which is overcompensated by ventilation of the entire shelf due to vertical mixing. {B}iogeochemical processes compensate this {DO} supply: {DO} is consumed by organic matter and zooplankton respiration, slightly compensated by regenerated and new primary production. {B}ecause of a sluggish shelf circulation during the summer season ({J}uly-{S}eptember, {JAS}), oxygen concentration declines in parts of the outer shelf bottom layer, in spite of a weaker surface primary production and organic matter export than during the heart of the cold season ({F}ebruary-{A}pril, {FMA}). {A}nalysis of the synoptic variability reveals the complexity of the {DO} response to the duration and intensity of upwelling and relaxation events, with the largest {DO} decrease of similar to 110 mu mo/{O}2{L}-1 associated with a strong upwelling event (cumulative upwelling index similar to 2{N}m-2day) obtained in 2016. {Y}ear to year variability indicates two periods of enhanced hypoxia in {FMA} 2017 and {JAS} 2016 characterized by a high retention of bottom waters over the shelf.},
  keywords = {{D}issolved oxygen ; {M}odelling ; {S}enegalese shelf ; {CROCO}-{PISCES} ; {SENEGAL} ; {ATLANTIQUE} ; {ZONE} {TROPICALE}},
  booktitle = {},
  journal = {{D}eep-{S}ea {R}esearch {P}art {II} : {T}opical {S}tudies in {O}ceanography},
  volume = {221},
  numero = {},
  pages = {105464 [17 p.]},
  ISSN = {0967-0645},
  year = {2025},
  DOI = {10.1016/j.dsr2.2025.105464},
  URL = {https://www.documentation.ird.fr/hor/fdi:010092866},
}