Alexandrium ostenfeldii

{{Short description|Species of single-celled organism}}

{{Speciesbox

| image =

| image_caption =

| genus = Alexandrium

| species = ostenfeldii

| authority = (Paulsen) Balech & Tangen

}}

Alexandrium ostenfeldii, also known as the sea fire, is a species of dinoflagellates. It is among the group of Alexandrium species that produce toxins causing paralytic shellfish poisoning.{{cite journal|title=The marine dinoflagellate Alexandrium ostenfeldii (Dinophyceae) as the causative organism of spirolide shellfish toxins|journal= Phycologia|year=2000|doi = 10.2216/i0031-8884-39-1-67.1|last1=Cembella|first1=A. D.|last2=Lewis|first2=N. I.|last3=Quilliam|first3=M. A.|volume=39|issue= 1|pages=67–74|bibcode= 2000Phyco..39...67C|s2cid=86509015}} These organisms have been found in the Baltic Sea.{{cite journal|title=Bloom forming Alexandrium ostenfeldii (Dinophyceae) in shallow waters of the Åland Archipelago, Northern Baltic Sea|year=2009|doi=10.1016/j.hal.2008.07.004|last1=Kremp|first1=Anke|last2=Lindholm|first2=Tore|last3=Dreßler|first3=Nicole|last4=Erler|first4=Katrin|last5=Gerdts|first5=Gunnar|last6=Eirtovaara|first6=Sanna|last7=Leskinen|first7=Elina|journal=Harmful Algae|volume=8|issue=2|pages=318–328}}{{cite news|title=Identifying Harmful Marine Dinoflagellates - Alexandrium ostenfeldii / Department of Botany, National Museum of Natural History, Smithsonian Institution|url=https://botany.si.edu/references/dinoflag/Taxa/Aostenfeldii.htm|work=Smithsonian Institution|access-date=1 December 2017}}