Chlorophyll fluorometers are inexpensive, easy to use, and consume little power. Their deployment in global and regional observation systems forms a basis for understanding primary production and ocean carbon cycles via estimates of chlorophyll concentration from fluorescence as a proxy for phytoplankton biomass. Yet, studies have shown large global biases in estimates of chlorophyll concentration based on fluorometry. Dr. Eric Rehm, Senior Oceanographer at Sea-Bird Scientific, will take you through our method towards an improved chlorophyll fluorometer in this session of Sea-Bird University.