Geophysical Research Letters

The impact of advective transport by the South Indian Ocean Countercurrent on the Madagascar plankton bloom

Authors

  • F. Huhn,

    1. Department of Physics, University of Santiago de Compostela, Santiago de Compostela, Spain
    2. Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida, USA
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  • A. von Kameke,

    1. Department of Physics, University of Santiago de Compostela, Santiago de Compostela, Spain
    2. Department of Engineering Sciences and Applied Mathematics, Northwestern University, Evanston, Illinois, USA
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  • V. Pérez-Muñuzuri,

    1. Department of Physics, University of Santiago de Compostela, Santiago de Compostela, Spain
    2. MeteoGalicia, Consellería de Medio Ambiente, Santiago de Compostela, Spain
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  • M. J. Olascoaga,

    1. Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida, USA
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  • F. J. Beron-Vera

    1. Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida, USA
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Abstract

[1] Based on ten years (1998–2007) of satellite ocean color data we analyze the spatiotemporal patterns in the seasonal Madagascar plankton bloom with respect to the advection of the recently discovered Southern Indian Ocean Countercurrent (SICC). In maps of Finite-time Lyapunov Exponents (FTLE) and Finite-Time Zonal Drift (FTZD) computed from altimetry derived velocities we observe a narrow zonal jet that starts at ∼25°S at the southern tip of Madagascar, an important upwelling region, and extends to the east further than the largest plankton blooms (∼2500 km). In bloom years, the jet coincides with large parts of the northern boundary of the plankton bloom, acting as a barrier to meridional transport. Our findings suggest that advection is an important and so far underestimated mechanism for the eastward propagation and the extent of the plankton bloom. This supports the hypothesis of a single nutrient source south of Madagascar.

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