Chrysochromulina rotalis is a marine haptophyte alga in the family Prymnesiaceae. Its specific epithet may reference the circular or rotating arrangement of scales observed on the cell surface. Like all Chrysochromulina species, cells are biflagellate and equipped with a haptonema — the coiling, three-membrane appendage unique to haptophytes. Organic scales of species-specific morphology cover the outer cell surface, constituting the primary taxonomic diagnostic feature for species identification within this morphologically similar genus. C. rotalis inhabits the photic zone of coastal marine and shelf waters, particularly in temperate and subarctic seas. The genus as a whole is a dominant component of the haptophyte nanoplankton community in North Atlantic and Arctic waters. Some congeners are capable of sustained bloom formation under conditions of thermal stratification and elevated nutrient availability. Chrysochromulina blooms have ecological consequences for marine food webs and, in the case of toxic species, for fisheries and aquaculture. The IUCN has not assessed the conservation status of C. rotalis, and the species remains Not Evaluated. Its ecology, physiology, and population genetics across oceanic regions are incompletely documented.