SEMINAR: "The global view of marine phytoplankton from ocean colour satellites"

Visible spectrum radiometry (or ocean colour remote sensing) is currently the only means of observing surface ocean biology at synoptic scales with high spatio-temporal resolution and it has long been a goal of the ocean colour community to identify phytoplankton taxa, species or size class. Better understanding of phytoplankton community abundance, structure, distribution and physiological rates is important for improving estimates of ecosystem function, the flux of atmospheric carbon dioxide to the oceans and ocean biogeochemical feedbacks on climate. For example, small cells may absorb nutrients and CO2 with higher efficiency under nutrient-limited conditions, whereas large cells can sink more rapidly and are thought to contribute more to export production. These size classes can be further subdivided into functional types with important roles in a range of elemental cycles (e.g. sulphur, silica). I will give an introductory ‘users guide’ to the approaches we have used to identify phytoplankton groups in the ocean and will present results from several recent studies that have significantly advanced this field through the development and application of satellite algorithms for estimating dominance and fractional contributions of PSC, PFT and size-specific photosynthetic rates.