Abstract
The Cape Verde (CV) Basin is the site of fronts and currents that function as both barriers and connectors between the tropical and subtropical oceans. Here we review former studies and analyze historical, satellite and numerical data in order to portray the oceanography of the CV Basin, with emphasis on its eastern boundary —the Mauritania Slope (MS) Ocean. This is complemented with the analysis of novel hydrographic data from the continental slope . The CV Basin is a dynamic region, forced by seasonally varying winds that drive both coastal and offshore upwelling , the latter linked to the Guinea Dome . Its circulation is controlled by the seasonally changing Dome to the south and southwest, with associated cyclonic currents, and by the CV frontal system to the north, with along-slope flow convergence and offshore export. The MS Ocean is the site of the Poleward Undercurrent , undistinguishable from the offshore Mauritania Current during winter–spring. The predominant thermocline water–mass is the nutrient-rich South Atlantic Central Water, almost pure in upper layers (100–300 m)—providing for the high primary production in the entire region—and with substantial North–Atlantic contribution in its lower part (300–550 m)—in what constitutes the poorly–ventilated low oxygen minimum zone ; nutrient concentrations keep increasing with depth until the core of the Antarctic Intermediate Water s (700–800 m). The CV Basin holds both the highest primary production and lowest oxygen concentrations for the entire tropical and subtropical North Atlantic gyres, with extensive implications on fisheries, but yet remains a largely unexplored oceanic region.
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Abbreviations
- AAIW:
-
Antarctic Intermediate Water
- ADT:
-
absolute dynamic topography
- ASCAT:
-
Advanced Scatterometer
- CC:
-
Canary Current
- CTD:
-
conductivity-temperature-depth
- CUC :
-
Canary Upwelling Current
- CV:
-
Cape Verde
- CVC:
-
Cape Verde Current
- CVFS:
-
Cape Verde frontal system
- CW:
-
central water
- dPUC:
-
deep Poleward Undercurrent
- ECCO2:
-
Estimating the Circulation and Climate of the Ocean phase II circulation model
- CG:
-
Guinea Current
- GD:
-
Guinea Dome
- ITCZ:
-
Inter-Tropical Convergence Zone
- lCW:
-
lower SACW
- MODIS:
-
Moderate Resolution Imaging Spectroradiometer
- MS:
-
Mauritania Slope
- NACW:
-
North Atlantic Central Water
- NADW:
-
North Atlantic Deep Water
- nCVC:
-
northern Cape Verde Current
- nNECC:
-
northern branch of the North Equatorial Counter Current
- PUC:
-
Poleward Undercurrent
- SACW:
-
South Atlantic Central Water
- SST:
-
sea surface temperature
- SW:
-
surface water
- uCW:
-
upper SACW
- WOA13:
-
World Ocean Atlas 2013 climatology
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Acknowledgements
The authors thank the crew, technicians and scientists on-board the R/V Vizconde de Eza during the Maurit cruises for their professionalism and assistance in the CTD sampling. We are also very grateful to our two reviewers, Dr Aissa Benazzouz and Dr Alonso Hernández-Guerra, for a number of useful comments and suggestions; we also wish to thank Dr Ana Ramos for encouraging us to write this chapter. This research has been supported by the VA-DE-RETRO project (CTM2014-56987) with funding from the Spanish government. We also wish to thank the national and international agencies (NOAA, NASA, Argo Data Center, AVISO) for making openly available the oceanographic data sets.
This work was undertaken within the framework of the EcoAfrik project and is ECOAFRIK publication number 20.
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Pelegrí, J.L., Peña-Izquierdo, J., Machín, F., Meiners, C., Presas-Navarro, C. (2017). Oceanography of the Cape Verde Basin and Mauritanian Slope Waters. In: Ramos, A., Ramil, F., Sanz, J. (eds) Deep-Sea Ecosystems Off Mauritania. Springer, Dordrecht. https://doi.org/10.1007/978-94-024-1023-5_3
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