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Influence of Tropical Instability Waves on Phytoplankton Biomass near the Marquesas Islands

Authors :
Martinez, Elodie
Raapoto, Hirohiti
Maes, Christophe
Maamaatuaihutapu, Keitapu
Laboratoire Terre-Ocean
Université de la Polynésie Française (UPF)
Laboratoire d'Océanographie Physique et Spatiale (LOPS)
Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Géopôle du Pacifique Sud (GePaSUD)
Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Source :
Remote Sensing, Vol 10, Iss 4, p 640 (2018), Remote Sensing, Remote Sensing, MDPI, 2018, 10 (4), ⟨10.3390/rs10040640⟩, Remote Sensing (2072-4292) (Mdpi), 2018-04, Vol. 10, N. 4, P. 640 (12p.), Remote Sensing, 2018, 10 (4), ⟨10.3390/rs10040640⟩, Volume 10, Issue 4, Pages: 640
Publication Year :
2018
Publisher :
MDPI AG, 2018.

Abstract

The Marquesas form an isolated group of small islands in the Central South Pacific where quasi-permanent biological activity is observed. During La Niña events, this biological activity, shown by a net increase of chlorophyll-a concentration (Chl, a proxy of phytoplankton biomass), is particularly strong. It has been hypothesized that this strong activity is due to iron-rich waters advected from the equatorial region to the Marquesas by tropical instability waves (TIWs). Here we investigate this hypothesis over 18 years by combining satellite observations, re-analyses of ocean data, and Lagrangian diagnostics. Four La Niña events ranging from moderate to strong intensity occurred during this period, and our results show that the Chl plume within the archipelago can be indeed influenced by such equatorial advection, but this was observed during the strong 1998 and 2010 La Niña conditions only. Chl spatio-temporal patterns during the occurrence of other TIWs rather suggest the interaction of large-scale forcing events such as an uplift of the thermocline or the enhancement of coastal upwelling induced by the tropical strengthening of the trades with the islands leading to enhancement of phytoplankton biomass within the surface waters. Overall, whatever the conditions, our analyses suggest that the influence of the TIWs is to disperse, stir, and, therefore, modulate the shape of the existing phytoplankton plume.

Details

Language :
English
ISSN :
20724292
Volume :
10
Issue :
4
Database :
OpenAIRE
Journal :
Remote Sensing
Accession number :
edsair.dedup.wf.001..be63028d1dfa7b8d632e6892082cceba
Full Text :
https://doi.org/10.3390/rs10040640⟩