35 pages, 23 figures, 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 offshoreupwelling, 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 AntarcticIntermediate Waters (700–800 m). The CV Basin holds both the highest primary production and lowest oxygen concentrations for the entire tropical and subtropicalNorth Atlantic gyres, with extensive implications on fisheries, but yet remains a largely unexplored oceanic region, This research has been supported by the VA-DE-RETRO project (CTM2014-56987) with funding from the Spanish government, Peer Reviewed

28 pages, We present the historical development of the nutrient stream concept, from the initial ideas on the nutrient‐bearing stratum and the transport of inorganic nutrients by the Gulf Stream to the large‐scale inorganic and organic connections in the entire Atlantic Ocean. We mostly analyze and discuss available literature but also present some novel calculations using cruise data and the velocity fields from numerical re‐analysis data. We first examine and discuss the structure of the Gulf Nutrient Stream, the significance of boundary exchange, and the importance of epipycnal and diapycnal processes. We then move to explore the subtropical and remote pathways into the Gulf Nutrient Stream, including the effect of the returning limb of the global overturning circulation, and end up reviewing the concept of nutrient irrigation of the subpolar gyre and its relevance in the spring–fall maintenance of the spring bloom. We close the chapter with some thoughts on the role of streams in the Earth system, as the key conduit for recycling properties within any ocean subsystem while simultaneously connecting the different subsystems, hence bringing about the complexity of the living planet, This research has been supported by the Spanish government through project VA-DE-RETRO (reference number CTM2014-56987-P). Ignasi VallèsCasanova and Dorleta Orúe-Echeverria have been supported by scholarships from the Spanish government, respectively from the FPI and FPU programs