Pyrocystis fusiformis

P. fusiformis's name is derived from its tapered or spindle shape.{{cite web|title=Classification -- Pyrocystis fusiformis|url=https://bioweb.uwlax.edu/bio203/f2013/eigner_rach/classification.htm|website=A Knight in Shining Armor|publisher=University of Wisconsin, La Crosse|access-date=24 January 2015}} P. fusiformis is non-motile, which is a characteristic of all members of family Pyrocystaceae, which lose their flagellum by the time these organisms are adults. P. fusiformis is considered a large dinoflagellate,{{Cite journal|last1=Bhovichitra|first1=Mahn|last2=Swift|first2=Elijah|date=1977|title=Light and dark uptake of nitrate and ammonium by large oceanic dinoflagellates: Pyrocystis noctiluca, Pyrocystis fusiformis, and Dissodinium lunula1|journal=Limnology and Oceanography|language=en|volume=22|issue=1|pages=73–83|doi=10.4319/lo.1977.22.1.0073|bibcode=1977LimOc..22...73B|issn=1939-5590|doi-access=free}}{{Cite journal|last=Sweeney|first=Beatrice M.|date=1982|title=Interaction of the Circadian Cycle with the Cell Cycle in Pyrocystis fusiformis|journal=Plant Physiology|volume=70|issue=1|pages=272–276|doi=10.1104/pp.70.1.272|issn=0032-0889|pmc=1067124|pmid=16662459}} with each cell being approximately 970 x 163 μm long and having a spherical diameter of 374 μm.{{cite web|last1=Foflonker|first1=Fatima|last2=Cowan|first2=John|title=Pyrocystis fusiformis|url=http://microbewiki.kenyon.edu/index.php/Pyrocystis_fusiformis|website=MicrobeWiki|publisher=Kenyon College|access-date=24 January 2015}} The cell's chloroplasts actually change the cell's shape as they move closer to the cell's wall in daytime and retract towards the nucleus at night.P. fusiformis is autotrophic, deriving their energy from the sun through photosynthesis.{{cite web|first1=Ryan|last1=Unknown|title=The Effects of DEET on Bioluminescent Dinoflagellates, Pyrocystis fusiformis|url=http://www.amnh.org/learn-teach/young-naturalist-awards/winning-essays2/2011-winning-essays/the-effects-of-deet-on-bioluminescent-dinoflagellates-pyrocystis-fusiformis|website=American Museum of Natural History|access-date=27 January 2015|date=2011}} P. fusiformis will only photosynthesize during daylight hours and mostly produce bioluminescence during night because of their circadian rhythm which controls both processes.{{cite web|last1=Haddock|first1=S.H.D |author1-link=Steven Haddock|last2=McDougall|first2=C.M.|last3=Case|first3=J.F.|title=Growing dinoflagellates at home|url=http://biolum.eemb.ucsb.edu/organism/dinohome.html|website=The Bioluminescence Web Page|publisher=University of California at Santa|access-date=27 January 2015|date=2011}}

File:Pyrocystis fusiformis bioluminescent dinoflagellates being poured in a flask.jpg

Bioluminescence occurs when an organism emits light through a chemical reaction{{Cite web|url=https://oceanservice.noaa.gov/facts/biolum.html|title=What is bioluminescence?|last=US Department of Commerce|first=National Oceanic and Atmospheric Administration|website=oceanservice.noaa.gov|language=EN-US|access-date=2020-04-27}} with the majority of the world's bioluminescent organisms living in the ocean.{{Cite journal|last=Widder|first=E. A.|date=2010-05-06|title=Bioluminescence in the Ocean: Origins of Biological, Chemical, and Ecological Diversity|journal=Science|volume=328|issue=5979|pages=704–708|doi=10.1126/science.1174269|pmid=20448176|bibcode=2010Sci...328..704W|s2cid=2375135 |issn=0036-8075}} The production of bioluminescence by P. fusiformis is thought to be a defense mechanism that startles grazers which would otherwise eat them or to illuminate grazers so that they, in turn may be more visible to their own predators, known as the "Burglar Alarm" theory.{{Cite journal|last1=Mesinger|first1=A. F.|last2=Case|first2=J. F.|date=1992|title=Dinoflagellate luminescence increases susceptibility of zooplankton to teleost predation|journal=Marine Biology|volume=112|issue=2|pages=207–210|doi=10.1007/bf00702463|bibcode=1992MarBi.112..207M |s2cid=84956226 |issn=0025-3162}}

In P. fusiformis bright blue light is produced through the reaction of the enzyme luciferase and protein-like compound luciferin in the cell's plasma membrane. Blue is believed to be the most common bioluminescent color produced in the ocean as blue light waves travels the farthest in seawater. The dinoflagellete type of luciferin used in this reaction is one of the four common types of luciferin found in the marine environment,{{Cite journal|last=Widder|first=E. A.|date=2010|title=Bioluminescence in the Ocean: Origins of Biological, Chemical, and Ecological Diversity|journal=Science|volume=328|issue=5979|pages=704–708|doi=10.1126/science.1174269|jstor=40655873|pmid=20448176|bibcode=2010Sci...328..704W|s2cid=2375135 |issn=0036-8075}} and the genome of P. fusiformis contains shared common origin with other dinoflagellates that contain the luciferase enzyme. In the laboratory, two different types bioluminescent flashes have been observed. One is bright and quick, while the other is dim but longer-lasting. The intensity and duration of these flashes are dependent on the time a cell has to recharge in between emitting light, with recovery periods varying between 15–60 minutes and 6 hours for fatigued cells.{{Cite journal|last1=Widder|first1=Edith A.|last2=Case|first2=James F.|date=1981-03-01|title=Two flash forms in the bioluminescent dinoflagellate,Pyrocystis fusiformis|journal=Journal of Comparative Physiology|language=en|volume=143|issue=1|pages=43–52|doi=10.1007/BF00606067|s2cid=41380750 |issn=1432-1351}}

P. fusiformis has a full life cycle of approximately 5–7 days and reproduces asexually. The reproduction phase creates 1 or 2 zoospores which grow inside of the parent's cell wall until they become new cells. Observed in the laboratory under culture, asexual reproduction begins when the protoplast contracts away from the parental cell wall. In P. fusiformis, the protoplasm contracts near the middle of the cell forming two lobes, as opposed to Pyrocystis lunula, which forms crescent moon-like shapes while dividing. Once the protoplasm divides, it differentiates into reproductive cells. These cells then swell very quickly, creating new parent cells.{{Cite journal|last1=Swift|first1=Elijah|last2=Durbin|first2=Edward, G.|date=1971|title=Similarities in the asexual reproduction of the oceanic dinoflagellates Pyrocystis fusiformis, Pyrocystis lunula, and Pyrocystis noctiluca|url=https://www.researchgate.net/publication/229964117|journal=Journal of Phycology|volume=7|issue=2|pages=89–96|doi=10.1111/j.1529-8817.1971.tb01486.x|bibcode=1971JPcgy...7...89S |s2cid=84742546 |via=ResearchGate}}

Phytoplankton including P. fusiformis play a large role in global carbon cycling by fixing carbon while also producing a large amount of oxygen through photosynthesis. Some oxygen produced by phytoplankton is dissolved into marine waters and helps support respiration for heterotrophic organisms. However, large quantities of oxygen diffuse into the atmosphere through surface waters, contributing up to 50% of the world’s atmospheric oxygen.{{Cite journal|last1=Field|first1=Christopher B.|last2=Behrenfeld|first2=Michael J.|last3=R|first3=James T.|last4=Falkowski|first4=Paul|date=1998|title=G.: Primary production of the biosphere: Integrating terrestrial and oceanic components|journal=Science|volume=281|issue=5374|pages=237–40|doi=10.1126/science.281.5374.237|pmid=9657713|bibcode=1998Sci...281..237F|citeseerx=10.1.1.1018.4584}} Phytoplankton also form the basis of the marine food chain and are preyed upon by various organisms, such as grass shrimp, mosquito fish, mysids, and copepods. They contribute to the primary production of the ocean through the fixing of carbon into usable energy.{{Cite journal|last=Morel|first=A.|date=2002-06-14|title=OCEANOGRAPHY: Small Critters--Big Effects|journal=Science|volume=296|issue=5575|pages=1980–1982|doi=10.1126/science.1072561|pmid=12065823|s2cid=83220906 |issn=0036-8075}}

It is estimated that P. fusiformis occurs most frequently at a depth of 60 and 100 meters in marine waters, tropical and subtropical bays and also oligotrophic waters, and has been found as deep as 200 meters. This species has been found in Taiwan, the Adriatic Sea, Black Sea, Canary Islands, Baja California, Brazil, India, China and Australia.{{cite web|last1=Guiry|first1=M.D.|last2=Guiry|first2=G.M.|title=Pyrocistis fusiformis|url=http://www.algaebase.org/search/species/detail/?species_id=Fe1c4cc44daf9ddfc|website=Algaebase|publisher=National University of Ireland|access-date=24 January 2015|date=29 May 2003}}

In oligotrophic water, nitrogen (N) is a limiting nutrient for phytoplankton growth.{{Cite web|url=https://en.wikipedia.org/w/index.php?title=Trophic_state_index&oldid=952343028|title=Trophic state index|date=April 21, 2020|website=Wikipedia|access-date=April 25, 2020}} Nitrate (NO⁻₃) and ammonium (NH⁺₄), both inorganic form of nitrogen, are most often taken up by phytoplankton and are necessary for growth and metabolic processes. P. fusiformis is known to metabolize both nitrate and ammonium at relatively equal rates during both the day and the night, and is able to take in nitrate at depths of 120m or greater, deeper than many other phytoplankton. P. fusiformis is also able to take advantage of surplus carbon (C) in surface waters by using what it needs for metabolic processes immediately, and then catabolizing and storing excess C for use at greater depths, allowing it have a relatively constant rate of cell division throughout the euphotic zone.{{Cite journal|last1=Rivkin|first1=Richard B.|last2=Swift|first2=Elijah|last3=Biggley|first3=William H.|last4=Voytek|first4=Mary A.|date=1984-04-01|title=Growth and carbon uptake by natural populations of oceanic dinoflagellates Pyrocystis noctiluca and Pyrocystis fusiformis|journal=Deep Sea Research Part A. Oceanographic Research Papers|language=en|volume=31|issue=4|pages=353–367|doi=10.1016/0198-0149(84)90089-X|bibcode=1984DSRA...31..353R|issn=0198-0149}}

P. fusiformis is interesting to humans as a natural phenomenon to observe in the ocean, in addition to being easily cultivated in a controlled environment at home and in classrooms for study. P. fusiformis is commonly grown for science{{cite web|last1=Whyte|first1=David|title=Bioluminescence: Investigating Glow-in-the-Dark Dinoflagellates|url=http://www.sciencebuddies.org/science-fair-projects/project_ideas/BioChem_p033.shtml|publisher=Science Buddies|access-date=24 January 2015|date=9 February 2014}} and art{{cite web|last1=Rober|first1=Mark|title=Glowing Algae Water Fountain|url=https://www.youtube.com/watch?v=mDmFSz8-r7g |archive-url=https://ghostarchive.org/varchive/youtube/20211212/mDmFSz8-r7g| archive-date=2021-12-12 |url-status=live|website=YouTube|access-date=24 January 2015|format=Video|date=30 July 2013}}{{cbignore}} projects.

Because P. fusiformis is important to scientific study as it only flashes when agitated and could be utilized in flow visualization to help spot differences in water flow or disruption of water by predators. P. fusiformis can also be used as a bioassay tool in order to detect pollutants in marine waters. Scientists measure the amount of light that P. fusiformis (and other dinoflagellates) emits in order to measure the effects of pollution since the amount of light produced is related to how healthy these organisms are.

P. fusiformis is also the main subject of a series of works by artist Erika Blumenfeld who has shown her work in museums and galleries around the world.{{cite web|last1=Goodfellow|first1=Melanie|title=CultureLab: Artists join researchers in climate change show|url=https://www.newscientist.com/blogs/culturelab/2012/05/the-many-faces-of-climate-change.html|website=New Scientist|access-date=27 January 2015|date=9 May 2012}} Her large scale photographs demonstrate the blue color that P. fusiformis produces when agitated. Working with scientists at the Scripps Institution of Oceanography, Blumenfeld photographs P. fusiformis in order to "activate a dialogue about our natural environment and our relationship to it."{{cite web|last1=Blumenfeld|first1=Erika|title=Bioluminescence - Work Statement|url=http://www.erikablumenfeld.com/artworks/gallery/bioluminescence|website=Erika Blumenfeld|access-date=27 January 2015|date=2015}}

{{Reflist}}

{{Taxonbar|from=Q7263640}}

Illustration on outer cover and note on inner cover. August 2022 European Journal of Phycology 57 (3)

Category:Protists described in 1885

Category:Gonyaulacales

Category:Bioluminescent dinoflagellates

Category:Dinoflagellate species