Phytoplankton phenology in the global ocean

In recent years, phytoplankton phenology has been proposed as an indicator to monitor systematically the state of the pelagic ecosystem and to detect changes triggered by perturbation of the environmental conditions. Here we describe the phenology of phytoplankton growth for the world ocean using remotesensing
ocean colour data, and analyse its variability between 1998 and 2007. Generally, the tropics and subtropics present long growing period (≈15–20 weeks) of low amplitude ( and Southern Annular Mode and negative phases of Multivariate El Ni˜no-Southern Oscillation index (El Ni˜no conditions), associated with enhanced water mixing and nutrients supply, generally sustain longer growth. On the basis of the results, perspectives are drawn on the utility of phenology as an organising principle for the analysis of pelagic ecosystem.