The colour of the ocean – or the spectra spectrum of light leaving its surface - contains information about the constituents in the water. Several satellites presently in orbit measure ocean colour to obtain measurements of different variables. First and foremost, oceanographers are interested in the amount of phytoplankton present; however, other variables can also be derived, such as the absorption by coloured dissolved organic matter and the backscattering coefficient. Algorithms to obtain such variables have been described since the mid-1990’s and have been improved ever since. In the early 2000’s, satellites with new spectral bands allowed us to measure additional variables. In particular, bands in the red introduced the possibility of measuring the light fluoresced from phytoplankton. Furthermore, new research suggests that ocean colour contains more untapped information. In this talk, I will review the basic concepts of ocean colour and present different aspects that our research group is working on. Dr. Yannick Huot obtained his B.Sc. in physics at the Université Laval and his M.Sc. and Ph.D. in oceanography at Dalhousie University. After pursuing post-doctoral studies at the Observatoire Oceanologique de Villefranche, he joined the Université de Sherbrooke, where he holds the Canada Research Chair in Earth Observation and Phytoplankton Ecophysiology. His field of research covers ocean optics and remote sensing as well as phytoplankton photophysiology. Having crossed the “salty divide”, his research also encompasses phytoplankton ecology in lakes.