Variabilities in sea-level and upper-ocean chlorophyll reveal the systematic influence of nonlinear eddies. The advent of satellite-based remote sensing of ocean color in the late 1970s ( 1 ) provided the first largescale views of chlorophyll distributions in the upper ocean. These distributions are a proxy for the biomass of phytoplankton, which drive oceanic productivity. More recently, ocean color measurements have been combined with satellite data on sea-surface height (SSH) and other physical properties of the ocean to elucidate the processes that regulate primary production in the sea. On page 328 of this issue, Chelton et al. ( 2 ) further advance this field by showing that ocean eddies exert a strong influence on near-surface chlorophyll.