Biophysical responses near equatorial islands in the Western Pacific Ocean during El Nino/La Nina transitions

The biological response in the western equatorial Pacific Ocean during El Nino/La Nina transitions and the underlying physical mechanisms were investigated. A chlorophyll a bloom was observed near the Gilbert Islands during the 2010 El Nino/La Nina transition, whereas no bloom was observed during the 2007 El Nino/La Nina transition. Compared to the previously observed bloom during the 1998 El Nino/La Nina transition, the 2010 bloom was weaker, lagged by 1-2 months, and was displaced eastward by similar to 200 km. Analysis suggested that the occurrence, magnitude, timing, and spatial pattern of the blooms were controlled by two factors: easterly winds in the western equatorial Pacific during the transition to La Nina and the associated island mass effect that enhanced vertical processes (upwelling and vertical mixing), and the preconditioning of the thermocline depth and barrier layer thickness by the preceding El Nino that regulated the efficiency of the vertical processes. Despite the similar strength of easterly winds in the western equatorial Pacific during the 1998 and 2010 transitions to La Nina, the 20092010 El Nino prompted a deeper thermocline and thicker barrier layer than the 1997-1998 El Nino that hampered the efficiency of the vertical processes in supplying nutrients from the thermocline to the euphotic zone, resulting in a weaker bloom

Hémoglobine C manifestations cliniques et biologiques

No Abstract Available J. Rech. Sci. Univ. Lomé (Togo) 2002, 6(1) : 205-20

Hétérogénéité génotypique du déficit en G6PD à l’Ouest de l’Afrique Sub-saharienne

abstract: Hématologie 2000; 6(HS):45info:eu-repo/semantics/nonPublishe

Boundary influences on HAB phytoplankton ecology in a stratification-enhanced upwelling shadow

International audienc

Combining point correlation maps with self-organising maps to compare observed and simulated atmospheric teleconnection patterns

We use a new method based on point correlation maps and self-organising maps (SOMs) to identify teleconnection patterns in 60 yr of National Centres for Environmental Prediction/National Centre for Atmospheric Research (NCEP/NCAR) sea level pressure (SLP) re-analysis data. The most prevalent patterns are the El Nino Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO) and the Southern Annular Mode (SAM). Asymmetries are found between base points in opposite centres of action of the NAO and the Pacific North America pattern (PNA). The SOM-based method is a powerful tool that allows us to efficiently assess how realistically teleconnections are reproduced in any climate model. The degree of agreement between modelled and re-analysis-based teleconnections (or between different models) can be summarised in a single plot. Here, we illustrate this by assessing the skill of the medium complexity climate model FORTE (Fast Ocean Rapid Troposphere Experiment). FORTE reproduces some realistic teleconnections, such as the Arctic Oscillation (AO), the NAO, the PNA, the SAM, the African Monsoon and ENSO, along with several other teleconnections, which resemble to varying degrees the corresponding NCEP patterns. However, FORTE tends to underestimate the strength of the correlation patterns and the patterns tend to be slightly too zonal. The accuracy of frequency of occurrence is variable between patterns. The Indian Ocean is a region where FORTE performs poorly, as it does not reproduce the teleconnection patterns linked to the Indian Monsoon. In contrast, the North and equatorial Pacific and North Atlantic are reasonably well reproduced

Targeted metagenomics and ecology of globally important uncultured eukaryotic phytoplankton

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