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| Menkes, Christophe; Kennan, Sc; Flament, Pierre; Dandonneau, Y; Masson, S; Biessy, B; Marchal, E; Eldin, G; Grelet, J; Montel, Y; Morliere, A; Lebourges-dhaussy, A; Moulin, C; Champalbert, G; Herbland, Alain. |
| [1] The equatorial Pacific and Atlantic oceans exhibit remarkable meridional undulations in temperature and chlorophyll fronts visible from space over thousands of kilometers and often referred to as tropical instability waves. Here, we present new observations of an ecosystem ranging through three trophic levels: phytoplankton, zooplankton and small pelagic fish whirling within a tropical vortex of the Atlantic ocean and associated with such undulations. Cold, nutrient and biologically rich equatorial waters are advected northward and downward to form sharp fronts visible in all tracers and trophic levels. The equatorward recirculation experiences upwelling at depth, with the pycnocline and ecosystem progressively moving toward the surface to reconnect... |
| Tipo: Text |
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| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00000/10049/9584.pdf |
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| Dandonneau, Y. |
| Oxygen concentrations were measured at discrete depths (0 to 250 m) at 20-day fixed station in an oligotrophic area (Proligo cruise of R/V Jean Charcot , 15 degree S, 173 degree E, September-October 1985). Measurements are available for both early morning and evening over a period of 14 days. Daily oxygen production is very variable, and does not permit a precise estimation of photosynthetic carbon fixation. Empirical orthogonal function analysis shows that the variability of the oxygen concentrations is null at the surface, increases evenly downwards, reaches a maximum at the depth of the nutricline and at the deep chlorophyll maximum, and decreases to null values at 187 m depth. Absence of a pronounced daily periodicity of the oxygen concentration is... |
| Tipo: Text |
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| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00268/37919/36000.pdf |
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