Chrysochromulina laurentiana is a marine haptophyte microalga in the genus Chrysochromulina, class Prymnesiophyceae, order Prymnesiales. The species epithet laurentiana may reference the Gulf of St. Lawrence or Laurentian waters of the North Atlantic, suggesting a type locality or early collection site in the western North Atlantic, though it has also been recorded from Norwegian and Swedish coastal environments. This transatlantic pattern is consistent with oceanic dispersal of marine microplankton or with convergent description from morphologically identical but geographically distinct populations. C. laurentiana is a nanoplankton organism characterized by the standard Chrysochromulina features: golden-brown chloroplasts, two flagella, a coiling haptonema, and a cell surface bearing organic scales whose specific morphology is species-diagnostic. The species inhabits coastal marine photic zones, contributing to primary production and microbial food web dynamics. In northern Atlantic waters, Chrysochromulina species including C. laurentiana form part of the mixed phytoplankton community that drives seasonal productivity cycles, particularly in spring and early summer when nutrient availability and stratification favor nanoplankton growth. The genus as a whole is known for sporadic bloom-forming behavior in eutrophic or stratified coastal fjords, though such events are not universally associated with all species. C. laurentiana has not been formally assessed under IUCN Red List criteria and is classified as Not Evaluated, consistent with the standard treatment of widely distributed marine microalgal taxa.