Karenia brevis
Karenia brevis | |
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Scientific classification ![]() | |
Domain: | Eukaryota |
Clade: | Diaphoretickes |
Clade: | SAR |
Clade: | Alveolata |
Phylum: | Myzozoa |
Superclass: | Dinoflagellata |
Class: | Dinophyceae |
Order: | Gymnodiniales |
Family: | Kareniaceae |
Genus: | Karenia |
Species: | K. brevis
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Binomial name | |
Karenia brevis (Davis) G. Hansen et Moestrup
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Karenia brevis is a microscopic, single-celled, photosynthetic organism in the genus
Each cell has two
History
The classification of K. brevis has changed over time as advances in technology are made.[4]
Karenia brevis was named for Dr. Karen A. Steidinger[5] in 2001, and was previously known as Gymnodinium breve and Ptychodiscus brevis. It was first named Gymnodinium brevis in 1948, but was later changed to Gymnodinium breve, which correlates with the guidelines of the International Code of Botanical Nomenclature. In 1979 it was categorized under the genus Ptychodiscus and named Ptychodiscus brevis as new research showed it fit better under this genus because of its morphology, biochemistry, and ultrastructure. Then in 1989, scientists agreed this organism should be referred to as its original name (G. breve). It was then reclassified and transferred to the new genus Karenia, which was established at the University of Copenhagen in 2000.
Karenia brevis was first identified in Florida in 1947, but anecdotal reports in the Gulf of Mexico date back to the 1530s.[1][6] Outbreaks of K. brevis have been known to occur since the Spanish explorers of the 15th and 16th centuries, as documented by Spanish explorers like Cabeza de Vaca.[citation needed] These explorers noted large fish kills that resemble the die offs seen in present-day due to K. brevis. C.C. Davis confirmed these die offs were due to K. brevis in 1948.[7]
Ecology and distribution
Karenia brevis has an optimum temperature range of 22–28 °C (72–82 °F),[8] an optimum salinity range of 25-45 Practical Salinity Units (PSU),[9] has adapted to "low-irradiance environments," and can utilize both organic and inorganic nitrogen and phosphorus compounds to survive.[10] In its normal environment, K. brevis will move in the direction of greater light[11] and against the direction of gravity,[12] which will tend to keep the organism at the surface of whatever body of water it is suspended within. The swimming speed of K. brevis is about one metre per hour[13] and the organism can be found throughout the year in the waters of the Gulf of Mexico at concentrations of ≤ 1,000 cell per liter.[2]
Scientists have been unable to determine a definitive geographic range for K. brevis specifically because it is difficult to separate from the ten other species of Karenia, but K. brevis is the most common species occurring in the Gulf of Mexico.[14]
Karenia brevis is the causative agent of
One researcher has stated that, "There is no single hypothesis that can account for blooms of K. brevis along the west coast of Florida".[10] However, like most algae, their occurrence and survival depends on a variety of factors in their environment including water temperature, salinity, light, and nutrients/compounds present in the water.[10] However it is suspected that abundant use of fertilizers in surrounding coastal areas as well as fertilizer run-off from more distant farms, carried by the rivers, might have an impact on algae growth.
Under favorable conditions, toxin-producing dinoflagellates such as K. brevis flourish and grow to high concentrations, an event termed a "harmful algal bloom" or a "HAB". While there are many different types of these HABs and the effects can vary, K. brevis is the causative agent of Florida Red Tides. Due to the toxin that K. brevis produces, these red tides can be detrimental to marine life and can even affect human populations along coasts where they occur.[16]
Impact on human health and activities
In areas where K. brevis is found at normal population levels, the organism is not known to cause harm to human health. It is only at times of unchecked population growth, resulting in harmful algal blooms, when the organism is of concern to human health and activities.
The uncontrolled mass explosions of K. brevis populations resulting in Florida Red Tide also has a significant financial impact on the affected coastal areas. The primary source of revenue generation in many of the communities affected by K. brevis red tides is tourism. During periods of red tides this important source of revenue is often lost to the impacted coastal communities of Florida, often on the scale of tens of millions of dollars.[18]
This particular protist is known to be harmful to humans, large fish, and other marine mammals. It has been found that the survival of scleractinian coral is negatively affected by brevetoxin. Scleractinian coral exhibits decreased rates of respiration when there is a high concentration of K. brevis.[3]
Effect of Karenia brevis on environment
![](http://upload.wikimedia.org/wikipedia/commons/thumb/a/af/Endangered_Florida_manatee_%28Trichechus_manatus%29_%287636816484%29.jpg/220px-Endangered_Florida_manatee_%28Trichechus_manatus%29_%287636816484%29.jpg)
Brevetoxins are a group of neurotoxic compounds released by K. brevis. At high concentration these brevetoxins can be fatal to fish, marine mammals, and birds.[19][20] Brevetoxins also pose a threat to corals.[21]
Large nearshore fish fatalities are caused by red-tide blooms.[22] Shorebirds can also get infected with brevetoxins by consuming fish.[23] Thus, red-tide blooms can have major level effects impacting the whole ecosystem. Additionally infected fish and shellfish pose a threat to the fishing industry and economy.[20][22]
K. brevis red tides have also been found to be a significant factor in the mortality of multiple species of sea turtles.[24] Specifically Kemp's ridleys, loggerheads, green turtles, and hawksbills, particularly along the west Florida coast.[24] Since red tide is a major cause of stranded sea turtles, it contributes to the vulnerability of this endangered species.[24]
K. brevis blooms pose other lethal health risks to marine animals like manatees. Extended occurrences of red tide blooms in the Gulf of Mexico have been associated with substantial instances of mortality in manatee populations[25]. Brevetoxins can lower manatee’s immune systems making them more at risk for other diseases.[25] Additionally, brevetoxin has been correlated with oxidative stress in manatees.[25]
Overall brevetoxins have grave effects on wildlife, and the multitude and compounded effects on entire marine ecosystems are not yet fully understood.
Detection and monitoring
Traditional methods for the detection of K. brevis are based on microscopy or pigment analysis. These are time-consuming, and typically require a skilled microscopist for identification.[26] Cultivation-based identification is extremely difficult and can take several months.
The traditional methods of detection and monitoring of K. brevis blooms from field measurements is labor-intensive and suffers from practical limitations on achieving real-time detection or monitoring. The "Brevebuster" is a deploy-able instrument that can be deployed on automated underwater vehicles or on stationary platforms that can optically detect the Florida red tides.[6] A molecular, real-time PCR-based approach for sensitive and accurate detection of K. brevis cells in marine environments has therefore been developed.[27] A real-time nucleic acid sequence-based amplification (NASBA) assay has been developed for detection of rbcL mRNA from K. brevis. NASBA is sensitive, rapid and effective, and may be used as an additional or alternative method to detect and quantify K. brevis in the marine environment.[28]
Another technique for the detection of K. brevis is multiwavelength spectroscopy, which uses a model-based examination of UV-vis spectra.[29] Methods of detection using satellite spectroscopy have also been developed.[30][31] Satellite images from Medium Resolution Imaging Spectrometer (MERIS) and Moderate Resolution Imaging Spectroradiometer (MODIS) ocean color sensor, identify K. brevis by making use of its chlorophyll fluorescence and low backscattering characteristics.[32][33][34] In addition to methods of detection of cells of K. brevis, enzyme-linked immunosorbent assay (ELISA) and liquid chromatography mass spectrometry (LCMS) have been developed for detecting brevetoxin in shellfish,[6][35] are more sensitive than the standard mouse bioassay, and as of 2008, were being considered by the Interstate Shellfish Sanitation Conference for regulatory use.
References
- ^ ISSN 1568-9883.
- ^ a b c "About Florida Red Tides". myfwc.com. Retrieved 22 October 2018.
- ^ .
- ^ "Red Tide K. Reikowski BIO 203". bioweb.uwlax.edu. Retrieved 24 October 2018.
- ^ "Bay Soundings". baysoundings.com.
- ^ a b c Lopez CB, Dortch Q, Jewett EB, Garrison D (2008). Scientific assessment of marine harmful algal blooms. Interagency Working Group on Harmful Algal Blooms, Hypoxia, and Human Health of the Joint Subcommittee on Ocean Science and Technology. Washington, D.C.
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- ^ ISSN 1568-9883.
- ^ Geesey, M. E., and P. A. Tester. 1993. Gymnodinium breveGymnodinium breve: ubiquitous in Gulf of Mexico waters, p. 251-256. InIn T. J. S. Smayda and Shimizu (ed.), Toxic phytoplankton blooms in the sea: Proceedings of the Fifth International Conference on Toxic Marine Phytoplankton. Elsevier Science Publishing, Inc., New York, N.Y.
- .
- ^ Steidinger, K. A.; Joyce Jr, E. A. (1973). "Florida red tides". State Fla. Dep. Nat. Resour. Educat. Ser. 17: 1–26.
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- ^ PMID 24727069.
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- ^ PMID 36781942.
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- ^ ISSN 0171-8630.
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- ^ PMID 30628577.
- ^ PMID 25678466.
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- ^ Spear, H. Adam, K. Daly, D. Huffman, and L. Garcia-Rubio. 2009. Progress in developing a new detection method for the harmful algal bloom species, Karenia brevis, through multiwavelength spectroscopy. HARMFUL ALGAE. 8:189–195.
- ^ Hu, C., et al. (2005) Red tide detection and tracing using MODIS fluorescence data: A regional example in SW Florida coastal waters, Remote Sensing of Environment 97(2005) 311–321 http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.115.4645&rep=rep1&type=pdf
- ^ Carvalho, G., et al. (2007) Detection of Florida "red tides" from SeaWiFS and MODIS imagery, Anais XIII Simposio Brasileiro de Sensoriamento Remoto, 21–26 Abril 2007 http://marte.dpi.inpe.br/col/dpi.inpe.br/sbsr@80/2006/11.07.00.35/doc/4581-4588.pdf
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Further reading
- Campbell, Lisa; Pepper, Alan E.; Ryan, Darcie E. (11 October 2014). "De novo assembly and characterization of the transcriptome of the toxic dinoflagellate Karenia brevis". BMC Genomics. 15 (888): 888. PMID 25306556.
- Ryan, Darcie; Pepper, Alan; Campbell, Lisa (11 October 2014). "De novo assembly and characterization of the transcriptome of the toxic dinoflagellate Karenia brevis". BMC Genomics. 15 (1): 888. PMID 25306556.
- Kirkpatrick, Barbara; Kohler, Kate; Byrne, Margaret (15 September 2014). "Human responses to Florida red tides: Policy awareness and adherence to local fertilizer ordinances". Science of the Total Environment. 493: 898–909. PMID 25003583.
- Özhan, Koray; Bargu, Sibel (10 June 2014). "Responses of sympatric Karenia brevis, Prorocentrum minimum, and Heterosigma akashiwo to the exposure of crude oil". Ecotoxicology. 23 (8): 1387–1398. S2CID 25052081.
- Naar, Jerome; Bourdelais, Andrea; Tomas, Carmelo (February 2002). "A Competitive ELISA to Detect Brevetoxins from Karenia brevis (Formerly Gymnodinium breve) in Seawater, Shellfish, and Mammalian Body Fluid". Environmental Health Perspectives. 110 (2): 179–185. PMID 11836147.
- Meyer, Kevin A.; O' Neil, Judith M.; Hitchcock, Gary L.; Heil, Cynthia A. (September 2014). "Microbial production along the West Florida Shelf: Responses of bacteria and viruses to the presence and phase of Karenia brevis blooms". Harmful Algae. 38 (Sp. Iss): 110–8. .