Akashiwo sanguinea is a marine dinoflagellate well known for forming blooms that result in red tides. The protist is unarmored (naked). Therefore, it lacks a thick cellulose wall, the theca, common in other genera of dinoflagellates. Reproduction of the phytoplankton species is primarily asexual.
Recently recognized as mixotrophic, A. sanguinea is capable of preying on various organisms. For example, A. sanguinea is found to be capable of ingesting the cyanobacterium Synechococcus sp. at values comparable to other heterotrophic phytoplankton. This suggests implications it may have on the grazing impact of Synechococcus.
Despite it lack of thecal plates, a prominent feature helpful in identifying armored flagellates, A. sanguinea is relatively large and easily recognizable. Like most dinoflagellates, one flagellum is complex, wrapping around the equator of the cell in a groove. The other flagellum extends out from the cell to help aid its movement through the water. A. sanguinea’s most prominent features are the lack of a nuclear envelope chamber and the apical groove’s large, clockwise path when viewed from the front of the cell. These features, along with observations and data from LSU rDNA sequencing, recently helped declare a new genus for this species (Hansen & Moestrup).
A. sanguinea covers a broad range of distributions. Frequent blooms exist off the coast of Florida and Southern California. Blooms dominated by this species have also been observed in Narragansett Bay, Rhode Island.
Behavior and physiology
A. sanguinea exhibits a diurnal vertical migration pattern, observed to move toward the sun in field experiments even before the start of the light cycle. In laboratory settings, the migration is light dependent but the direction of movement is not solely explained by positive phototaxis. It has also been shown to swim across large gradients in temperature. However, more study is needed to determine the organisms’ migratory behavior.
A. sanguinea responds to certain changes in the water column by forming subsurface chlorophyll maximum layers in the marine environment. A study off of Southern California’s coast observed a subsurface layer when nitrate was limiting to the organism. A. sangiunea’s subsurface chlorophyll maximum layer has contributed to the success of larval anchovy growth on California’s coastline. The larva have been observed to ingest this organism and not other species such as Chaetocerus sp. and Thalassiosira sp. suggesting a preference for A. sanguinea over other dinoflagellates.
Context and content
The names listed above were used during prior research on the organism. The genus is now redefined into four new genera. Gymnodinium was one of many dinoflagellate genera declared when taxonomic nomenclature was limited to features only visible with the light microscope. In 2000, Hansen and Moestrup analyzed ultrastructural details of the organism using large-subunit (LSU) rDNA sequencing. Aided by this new technology, the scientists were able to declare variations in the path of the apical groove of the organism (found on the flagellar apparatus). Since the apical groove varies among species, the scientists used it to indicate differences between the unarmored flagellates. Akashiwo was one of four new genera that was redefined using the analysis.
Akashiwo sanguinea has been correlated to Harmful Algal Blooms (HABs), but more study is needed to make sense of the blooms.
The protist can produce mycosporine-like amino acids (MAAs) which are water-soluble surfactants. A red tide caused by A. sanguinea was coincident with widespread seabird mortality across fourteen different species of birds in November–December 2007 in Northeastern Monterey Bay, California. Plankton samples showed A. sanguinea as the dominant flagellate in the bloom. Affected birds accumulated a proteinaceous material on their feathers, causing a loss in the natural water repellency. However no toxins, such as domoic acid, saxitoxin or brevetoxin was detected in the water. It was the first documented case of its tide causing harm to birds.
- P. E. Hargraves (June 14, 2011). "Akashiwo sanguinea". Protists of the Indian River Lagoon. Smithsonian Institution. http://www.sms.si.edu/IRLSPEC/Akashi_sangui.htm. Retrieved October 27, 2011.
- Carol M. Lalli & Timothy R. Parsons (1993). Biological Oceanography: an Introduction (2nd ed.). Elsevier Butterworth-Heinemann. pp. 42–45. ISBN 0-7506-3384-0.
- K. R. Bockstahler & D. W. Coats (1993). "Grazing of the mixotrophic dinoflagellate Gymnodinium sanguineum on ciliate populations of Chesapeake Bay". Marine Biology 116 (3): 477–487. doi:10.1007/BF00350065.
- Hae Jin Jeong, Jae Yeon Park, Jae Hoon Nho, Myung Ok Park, Jeong Hyun Ha, Kyeong Ah Seong, Chang Jeng, Chi Nam Seong, Kwang Ya Lee & Won Ho Yih (2005). "Feeding by red-tide dinoflagellates on the cyanobacterium Synechococcus". Aquatic Microbial Ecology 41 (2): 131–143. doi:10.3354/ame041131.
- Charles B. Miller (2004). Biological Oceanography. Blackwell. pp. 26–32. ISBN 0-632-05536-7.
- N. Daugbjerg, G. Hansen, J. Larsen & Ø. Moestrup (2000). "Phylogeny of some of the major genera of dinoflagellates based on ultrastructure and partial LSU rDNA sequence data, including the erection of three new genera of unarmoured dinoflagellates" (PDF). Phycologia 39 (4): 302–317.
- David A. Jessup, Melissa A. Miller, John P. Ryan, Hannah M. Nevins,, Heather A. Kerkering, Abdou Mekebri, David B. Crane, Tyler A. Johnson & Raphael M. Kudela (2009). "Mass stranding of marine birds caused by a surfactant-producing red tide". PLoS ONE 4 (2): e4550. doi:10.1371/journal.pone.0004550. PMC 2641015. PMID 19234604.
- Reuben Lasker (1975). "Field criteria for survival of anchovy larvae: the relation between inshore chlorophyll maximum layers and successful first feeding" (PDF). Fishery Bulletin 73 (3): 453–462.
- Theodore J. Smayda (1957). "Phytoplankton studies in Lower Narragansett Bay". Limnology and Oceanography 2 (4): 342–359. JSTOR 2832835.
- J. J. Cullen & S. G. Horrigan (1981). "Effects of nitrate on the diurnal vertical migration, carbon to nitrogen ratio, and the photosynthetic capacity of the dinoflagellate Gymnodinium splendens". Marine Biology 62 (2–3): 81–89. doi:10.1007/BF00388169.
- F. M. H. Reid, E. Stewart, R. W. Eppley & D. Goodman (1978). "Spatial distribution of phytoplankton species in chlorophyll maximum layers off Southern California". Limnology and Oceanography 23 (2): 219–226. JSTOR 2835393.