FN Archimer Export Format
PT J
TI Effects of upwelling duration and phytoplankton growth regime on dissolved oxygen levels in an idealized Iberian Peninsula upwelling system
BT 
AF Bettencourt, João H.
   Rossi, Vincent
   Renault, Lionel
   Haynes, Peter
   Morel, Yves
   Garçon, Véronique
AS 1:1;2:2;3:5;4:3;5:1;6:4;
FF 1:;2:;3:;4:;5:;6:;
C1 LEGOS, University of Toulouse, CNES, CNRS, IRD, UPS, Toulouse 31400, France
   MIO (UM 110, UMR 7294), CNRS, Aix-Marseille Univ., Univ. Toulon, IRD, 13288, Marseille, France
   Department of Applied Mathematics and Theoretical Physics, University of Cambridge, England
C2 OBSERV MIDI PYRENEES, FRANCE
   UNIV AIX MARSEILLE, FRANCE
   UNIV CAMBRIDGE, UK
   CNRS, FRANCE
   IRD, FRANCE
IF 1.74
TC 5
UR https://archimer.ifremer.fr/doc/00516/62747/67135.pdf
   https://archimer.ifremer.fr/doc/00516/62747/74021.pdf
LA English
DT Article
CR MOUTON 07/01
   MOUTON 07/02
   MOUTON 07/03
BO Pourquoi pas ?
AB We apply a coupled modelling system composed of a state-of-the-art hydrodynamical model and a low complexity biogeochemical model to an idealized Iberian Peninsula upwelling system to identify the main drivers of dissolved oxygen variability and to study its response to changes in the duration of the upwelling season and in phytoplankton growth regime. We find that the export of oxygenated waters by upwelling front turbulence is a major sink for nearshore dissolved oxygen. In our simulations of summer upwelling, when phytoplankton population is generally dominated by diatoms whose growth is largely enhanced by nutrient input, net primary production and air-sea exchange compensate dissolved oxygen depletion by offshore export over the shelf. A shorter upwelling duration causes relaxation of upwelling winds and a decrease in offshore export, resulting in a slight increase of net dissolved oxygen enrichment in the coastal region as compared to longer upwelling durations. When phytoplankton is dominated by groups less sensitive to nutrient inputs, growth rates decrease and the coastal region becomes net heterotrophic. Together with the physical sink, this lowers the net oxygenation rate of coastal waters, that remains positive only because of air-sea exchanges. These findings help disentangling the physical and biogeochemical controls of dissolved oxygen in upwelling systems and, together with projections of increased duration of upwelling seasons and phytoplankton community changes, suggest that the Iberian coastal upwelling region may become more vulnerable to hypoxia and deoxygenation. 
PY 2020
PD MAY
SO Nonlinear Processes In Geophysics
SN 1023-5809
PU European Geosciences Union (EGU)
VL 27
IS 2
UT 000537115200001
BP 277
EP 294
DI 10.5194/npg-27-277-2020
ID 62747
ER

EF