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Journal of Oceanography

, Volume 52, Issue 3, pp 275–299 | Cite as

The North Atlantic nutrient stream

  • J. L. Pelegrí
  • G. T. Csanady
  • A. Martins
Article

Abstract

Western boundary currents are the locus of intense nutrient transport, or nutrient streams. The largest fraction of this transport takes place in the upper-thermocline layers, between the surface layers (where speed reaches a maximum) and the nutrient bearing strata of the subtropical gyres (where nutrient concentration is maximum). The core of the nutrient stream of the North Atlantic subtropical gyre is located slightly offshore the Gulf Stream, its density coordinate centered on the 26.5−27.3σθ−band, approximately constant along the axis of the stream. During late spring and summer the nutrient stream reaches the surface seasonal mixed layer at the outcropping of this isopycnal band. We argue that this must be a principal factor sustaining the seasonal high productivity of the subpolar North Atlantic Ocean. Additionally, we investigate the possibility of intermittent shear-induced diapycnal mixing in the upper-thermocline layers of the Gulf Stream, induced by frontogenesis taking place during some phase of the meanders. Here we illustrate that diapycnal mixing has a maximum at the location of the nutrient stream, being associated to observed nutrient anomalies. We suggest that diapycnal mixing associated to the passage of steep meanders brings nutrients from the nutrient stream to the shallow photic layers, and sustains intermittent (day-to-week) patchy (10–100 km) productivity over the stream itself.

Keywords

Mixed Layer Late Spring Western Boundary Principal Factor Gulf Stream 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Oceanographic Society of Japan 1996

Authors and Affiliations

  • J. L. Pelegrí
    • 1
  • G. T. Csanady
    • 2
  • A. Martins
    • 2
  1. 1.Facultad de Ciencias del MarUniversidad de Las Palmas de Gran CanariaCanary IslandsSpain
  2. 2.Center for Coastal Physical OceanographyOld Dominion University

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