Show simple item record

dc.contributor.authorMasotti, I.
dc.contributor.authorAlvain, S.
dc.contributor.authorMoulin, C.
dc.contributor.authorAntoine, David
dc.contributor.editorEGU General Assembly 2009
dc.identifier.citationMasotti, I. and Alvain, S. and Moulin, C. and Antoine, D. 2009. Variability in global ocean phytoplankton distribution over 1979-2007, in Proceedings of the EGU General Assembly, Apr 19-24 2009. Vienna, Austria: European Geosciences Union.

Recently, reanalysis of long-term ocean color data (CZCS and SeaWiFS; Antoine et al., 2005) has shown that world ocean average phytoplankton chlorophyll levels show an increase of 20% over the last two decades. It is however unknown whether this increase is associated with a change in the distribution of phytoplankton groups or if it simply corresponds to an increase of the productivity. Within the framework of the GLOBPHY project, the distribution of the phytoplankton groups was monitored by applying the PHYSAT method (Alvain et al., 2005) to the historical ocean color data series from CZCS, OCTS and SeaWiFS sensors. The PHYSAT algorithm allows identification of several phytoplankton, like nanoeucaryotes, prochlorococcus, synechococcus and diatoms. Because both sensors (OCTS-SeaWiFS) are very similar, OCTS data were processed with the standard PHYSAT algorithm to cover the 1996-1997 period during which a large El Niño event occurred, just before the SeaWiFS era. Our analysis of this dataset (1996-2006) evidences a strong variability in the distribution of phytoplankton groups at both regional and global scales. In the equatorial region (0°-5°S), a three-fold increase of nanoeucaryotes frequency was detected in opposition to a two-fold decrease of synechococcus during the early stages of El Niño conditions (May-June 1997, OCTS). The impact of this El Niño is however not confined to the Equatorial Pacific and has affected the global ocean.The processing of CZCS data with PHYSAT has required several adaptations of this algorithm due to the lower performances and the reduced number of spectral bands of the sensor. Despites higher uncertainties, the phytoplankton groups distribution obtained with CZCS is globally consistent with that of SeaWiFS. A comparison of variability in global phytoplankton distribution between 1979-1982 (CZCS) and 1999-2002 (SeaWiFS) suggests an increase in nanoeucaryotes at high latitudes (>40°) and in the equatorial region (10°S-10°N ) for prochlorococcus and synechococcus during 1999-2002. Our results show variability in global ocean phytoplankton distribution over a 20-year timescale. Strong variability observed over the inter-annual and inter-decadal scales are shown and tentatively explained using environmental variables.

dc.publisherEGU General Assembly 2009
dc.titleVariability in global ocean phytoplankton distribution over 1979-2007
dc.typeConference Paper
dcterms.source.titleProceedings from EGU General Assembly 2009
dcterms.source.seriesProceedings from EGU General Assembly 2009
dcterms.source.conferenceEGU General Assembly 2009
dcterms.source.conference-start-dateApr 20 2009
dcterms.source.conferencelocationVienna, Austria
dcterms.source.placeVienna, Austria
curtin.accessStatusFulltext not available

Files in this item


This item appears in the following Collection(s)

Show simple item record