Stirring of the northeast Atlantic spring bloom: A Lagrangian analysis based on multisatellite data
Article first published online: 4 AUG 2007
Copyright 2007 by the American Geophysical Union.
Journal of Geophysical Research: Oceans (1978–2012)
Volume 112, Issue C8, August 2007
How to Cite
2007), Stirring of the northeast Atlantic spring bloom: A Lagrangian analysis based on multisatellite data, J. Geophys. Res., 112, C08005, doi:10.1029/2006JC003927., , , and (
- Issue published online: 4 AUG 2007
- Article first published online: 4 AUG 2007
- Manuscript Accepted: 16 MAY 2007
- Manuscript Revised: 26 JAN 2007
- Manuscript Received: 7 SEP 2006
- spring bloom;
- Lyapunov exponents
 The effect of the geostrophic stirring on phytoplankton variability during the northeast Atlantic spring bloom is studied by analyzing satellite derived surface chlorophyll, sea surface temperature, and sea surface height. The calculation of unstable manifolds is used as a diagnostic of the transport properties of the geostrophic velocity field (calculated from the sea surface height). We identify two mechanisms by which the geostrophic velocity field acts on chlorophyll patterns. The first mechanism is a direct effect of the horizontal transport on already formed chlorophyll. By acting as “sticking” transport barriers, the unstable manifolds are shown to (1) modulate the fronts of already formed phytoplankton in lobular structures, (2) create spiralling chlorophyll anomalies within eddies, and (3) produce chlorophyll filaments. The second mechanism is an indirect effect on in situ chlorophyll production mediated by nutrient upwelling. Supported by a recent study on the vertical velocities of the northeast Atlantic (Legal et al., 2006), we argue that the horizontal unstable manifolds also shape the filamentary, vertical velocity cells, and hence the patterns of in situ produced chlorophyll through submesoscale vertical nutrient injection.