During Summer 2019, Nicole and Heather worked together with Susanne on the quantification of carbon and nitrogen phytoplankton biomass. During this SURFO project, they compared 3D cell volumes obtained using cutting-edge microscopy with the classic 2D biovolume estimates from classic microscopy. They also studied the impact of growth conditions on phytoplankton biovolume, and on C and N cell content. This is the featured articles of the March/April 2021 issue of Journal of Plankton Research, nicely illustrated by the image processing performed by Cynthia Beth-Rubin.