Estimation and analysis of the seasonal, inter-annual and decadal biogeochemical variability of the world’s coastal waters by remote sensing and their impacts on higher trophic levels – GlobCoast

Satellite remote sensing now allows for the collection of various physical and biological parameters at regional and global scales and at different temporal resolutions which are not accessible to other sampling methods. The first objective of the present project is to assess and analyse the seasonal, inter-annual, and decadal evolution of the global coastal waters in terms of biogeochemical composition as revealed from satellite ocean colour observations, for the very first time. Basic (inherent optical properties (IOPs), chlorophyll a (Chl), as a proxy for phytoplankton biomass and suspended particulate matter (SPM) concentrations) as well as more innovative products (particulate and dissolved organic carbon POC and DOC) will be assessed from new approaches developed in the frame of GlobCoast.

In the second part of the project, time series for the latter biogeochemical parameters will be analysed conjointly with various physical forcing parameters as obtained from remote sensing, in situ measurements, and modelling. This will help to gain a better understanding of the origins of the temporal variability of biogeochemical parameters over the coastal ocean. This part will be preferentially performed over three highly contrasted areas covering a great variety of environmental, biological and bio-optical conditions encountered in coastal areas: the English Channel and the North Sea, some major coastal upwelling systems, and the Amazon-influenced coast (mainly French Guiana).

Besides its fundamental role in marine biogeochemical cycles, phytoplankton, which is at the basis of the marine food web, transfers energy to higher trophic levels and its dynamics influences directly and indirectly the biodiversity of some trophic groups such as zooplankton, fishes and marine mammals. The third main objective of this project is to analyse the potential link between the variability of the environmental parameters as assessed in the first parts of the project, and the variance in the recruitment and stocks of higher trophic level organisms (fishes). While fishing pressure has a strong impact on recruitment and stocks, the contribution of environmental fluctuations to the variability in recruitment is now clearly demonstrated, especially thanks to remotely sensed data from satellite. This last part will be performed over the English Channel and the North Sea, and some major coastal upwelling systems.