Inferring the seasonal evolution of phytoplankton groups in the Senegalo‐Mauritanian upwelling region from satellite ocean‐color spectral measurements. Issue 9 (30th September 2015)

• Record Type: Journal Article
• Authors: Farikou, O.; Sawadogo, S.; Niang, A.; Diouf, D.; Brajard, J.; Mejia, C.; Dandonneau, Y.; Gasc, G.; Crepon, M.; Thiria, S.
• Is Part Of: Journal of geophysical research. Volume 120:Issue 9(2015:Sep.)
• Page Start: 6581
• Page End: 6601
• Publication Date: 2015-09-30
• Subjects: Oceanography -- Periodicals; 551.4605
• DOI: 10.1002/2015JC010738
• Languages: English
• ISSNs: 2169-9275

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>We have investigated the phytoplankton dynamics of the Senegalo‐Mauritanian upwelling region, which is a very productive region, by processing a 13 year set of SeaWiFS satellite ocean‐color measurements using a PHYSAT‐like method. We clustered the spectra of the ocean‐color normalized reflectance (reflectance normalized by a reflectance dependent on chlorophyll‐<italic>a</italic> concentration only) into 10 significant spectral classes using a Self‐Organized Map (SOM) associated with a hierarchical ascendant classification (HAC). By analyzing a 13 year climatology of these classes, we have been able to outline a coherent scenario describing the Senegalo‐Mauritanian upwelling region in terms of spatiotemporal variability of phytoplankton groups: during the onset of the upwelling (December–February), we mainly observed nanoeukaryote‐type phytoplankton in the coastal area; in April–May, the period corresponding to the maximum chlorophyll‐<italic>a</italic> concentration, the nanoeukaryote types were replaced by diatom types. This scenario is in agreement with microscope phytoplankton cell observations done during several past cruises.</p> </abstract>