Aphanizomenon flos-aquae

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Aphanizomenon flos-aquae
Aphanizomenon colony fluorescence microscopy.jpg
Scientific classification
Kingdom: Bacteria
Phylum: Cyanobacteria
Class: Cyanophyceae
Order: Nostocales
Family: Nostocaceae
Genus: Aphanizomenon

Aphanizomenon flos-aquae

Aphanizomenon flos-aquae is a brackish and freshwater species of cyanobacteria found around the world, including the Baltic Sea and the Great Lakes.


Aphanizomenon flos-aquae bloom on the Upper Klamath Lake, Oregon

Aphanizomenon flos-aquae can form dense surface aggregations in freshwater (known as "cyanobacterial blooms").[1] These blooms occur in areas of high nutrient loading, historical or current.


Aphanizomenon flos-aquae has both toxic and nontoxic forms.[2][unreliable source?][3] Most sources worldwide are toxic, containing both hepatic and neuroendotoxins.[4]

Most cyanobacteria (including Aphanizomenon) produce BMAA, a neurotoxin amino acid implicated in ALS/Parkinsonism.[5][6][7]

Toxicity of A. flos-aquae has been reported in Canada,[8] Germany[9][10] and China.[11]

Aphanizomenon flos-aquae is known to produce endotoxins, the toxic chemicals released when cells die. Once released (lysed), and ingested, these toxins can damage liver and nerve tissues in mammals. In areas where water quality is not closely monitored, the World Health Organization has assessed toxic algae as a health risk, citing the production of anatoxin-a, saxitoxins, and cylindrospermopsin.[12] Dogs have been reported to have become ill or have fatal reactions after swimming in rivers and lakes containing toxic A. flos-aquae.

Microcystin toxin has been found in all 16 samples of A. flos-aquae products sold as food supplements in Germany and Switzerland, originating from Lake Klamath: 10 of 16 samples exceeded the safety value of 1 µg microcystin per gram.[13] University professor Daniel Dietrich warned parents not to let children consume A. flos-aquae products, since children are even more vulnerable to toxic effects, due to lower body weight, and the continuous intake might lead to accumulation of toxins. Dietrich also warned against quackery schemes selling these cyanobacteria as medicine against illnesses such as attention deficit hyperactivity disorder, causing people to omit their regular drugs.

Medical research[edit]

A Canadian study studying the effect of A. flos-aquae on the immune and endocrine systems, as well as on general blood physiology, found that eating it had a profound effect on natural killer cells (NKCs).[14] A. flos-aquae triggers the movement of 40% of the circulating NKCs from the blood to tissues.

As a food supplement[edit]

Some compressed tablets of powdered A. flos-aquae cyanobacteria (named as "blue green algae") have been sold as food supplements, notably those filtered from Upper Klamath Lake in Oregon.[15]

Klamath Lake[edit]

Main article: Upper Klamath Lake

Upper Klamath Lake (sometimes called Klamath Lake) is a large, shallow freshwater lake east of the Cascade Range in south central Oregon in the United States. The largest freshwater body in Oregon, it is approximately 20 mi (32 km) long and 8 mi (12.9 km) wide and extends northwest from the city of Klamath Falls. It sits at an elevation of 4140 ft (1262 m).

The lake depth fluctuates due to regulation of its water supply, ranging from 8 ft (2.5 m) to 60 f (18 m) deep at average levels. The lake level is kept within 1261 to 1264 m above sea level.[16] It is fed by several sources, including the Williamson River and is drained by the Link River, which issues from the south end of the lake. It is connected by a short channel to the smaller Agency Lake to the north. The Upper Klamath National Wildlife Refuge sits along the north edge of the lake.

Upper Klamath Lake is located in the high desert southernmost part of the state of Oregon. The lake is protected to the northwest by the Cascade Mountains with an arid sagebrush steppe to the east and south. The lake is fed by 17 rivers that deposit an average of 50,000 tons of mineral-rich silt from the surrounding 4,000-square-mile (10,000 km2) volcanic basin, making Upper Klamath Lake one of the richest nutrient traps in the world.[citation needed] The lake waters and its sediments have a high trace element concentration due to a prehistoric volcanic eruption event (more than 7700y/A).[citation needed] The event covered the area with millions of tons of mineral ash as far north as the Canada–US border. The regions volcanic legacy is associated with the Pacific Ring of Fire,[citation needed] a geologically active region that experiences large-scale volcanic, tectonic, and glacial events.

The massive blooms of A. flos-aquae in Upper Klamath Lake affect the dynamics of the system significantly. In many years the blooms crash during the summer. The subsequent decomposition of the massive amounts of organic matter can deplete the water column of dissolved oxygen producing severely impaired conditions for fish species, including redband trout (Oncorhynchus mykiss) and two endangered species of suckers, the Lost River sucker (Deltistes luxatus) and shortnose sucker (Chasmistes brevirostris). This decomposition also releases previously unavailable nitrogen into the water, often fueling rapid growth of the cyanobacterium Microcystis aeruginosa, which is known to produce the hepatotoxin microcystin. It is widely believed that these dynamics are a central factor in the lack of recruitment of the two endangered sucker species, thereby contributing to their continued decline.

See also[edit]


  1. ^ "Cyanobacteria/Cyanotoxins". US EPA. Retrieved 23 Oct 2015. 
  2. ^ Jensen, Gitte S.; Ginsberg, Donald I.; Drapeau, Christian (2001). "Blue-Green Algae as an Immuno-Enhancer and Biomodulator" (PDF). Journal of the American Nutraceutical Association. 3 (4): 24–30. Retrieved 18 May 2012. 
  3. ^ Carmichael, Wayne W. (January 1994). "The Toxins of Cyanobacteria". Scientific American. 270 (1): 78–86. doi:10.1038/scientificamerican0194-78. ISSN 0036-8733. PMID 8284661. 
  4. ^ Karina Preußela, Fastnera Jutta; Federal Environmental Agency, FG II 3.3, Corrensplatz 1, 14195 Berlin, Germany; Department of Limnology of Stratified Lakes, Institute of Freshwater Ecology and Inland Fisheries, Alte Fischerhütte 2, 16775 Stechlin, Germany; 15 October 2005[verification needed]
  5. ^ Cox, PA; Sacks, OW. (2002). "Cycad neurotoxins, consumption of flying foxes, and ALS-PDC disease in Guam". Neurology. 58 (6): 956–9. doi:10.1212/wnl.58.6.956. PMID 11914415. 
  6. ^ Holtcamp W (2012). "The Emerging Science of BMAA: Do Cyanobacteria Contribute to Neurodegenerative Disease?". Environmental Health Perspectives. 120 (3): 110–16. doi:10.1289/ehp.120-a110. PMC 3295368free to read. PMID 22382274. 
  7. ^ Jonasson S, Eriksson J, Berntzon L, Spácil Z, Ilag LL, Ronnevi LO, Rasmussen U, Bergman B (2010). "Transfer of a cyanobacterial neurotoxin within a temperate aquatic ecosystem suggests pathways for human exposure". Proceedings of the National Academy of Sciences. 107 (20): 9252–7. Bibcode:2010PNAS..107.9252J. doi:10.1073/pnas.0914417107. 
  8. ^ Saker ML, Jungblut AD, Neilan BA, Rawn DF, Vasconcelos VM (October 2005). "Detection of microcystin synthetase genes in health food supplements containing the freshwater cyanobacterium Aphanizomenon flos-aquae". Toxicon. 46 (5): 555–62. doi:10.1016/j.toxicon.2005.06.021. PMID 16098554. 
  9. ^ Preussel K, Stüken A, Wiedner C, Chorus I, Fastner J (February 2006). "First report on cylindrospermopsin producing Aphanizomenon flos-aquae (Cyanobacteria) isolated from two German lakes". Toxicon. 47 (2): 156–62. doi:10.1016/j.toxicon.2005.10.013. PMID 16356522. 
  10. ^ Toxin content and cytotoxicity of algal dietary supplements Archived 19 December 2013 at the Wayback Machine.‹The template Wayback is being considered for merging.› , by Dr. Alexandra H. Heussner
  11. ^ Chen Y, Liu J, Yang W (May 2003). "Effect of Aphanizomenon flos-aquae toxins on some blood physiological parameters in mice". Wei Sheng Yan Jiu [Journal of Hygiene Research] (in Chinese). 32 (3): 195–7. PMID 12914277. 
  12. ^ World Health Organization (2006). Guidelines for drinking-water quality. First addendum to third edition. Volume 1. Recommendations. Geneva: World Health Organization. ISBN 978-92-4-154674-4. 
  13. ^ "AFA-Algen – Giftcocktail oder Gesundheitsbrunnen?" [AFA algae - toxic cocktail fountain or health?] (Translated from German). Universität Konstanz. Archived from the original on 1 May 2008. Retrieved 18 May 2012. 
  14. ^ Effects of the Blue Green Algae Aphanizomenon flos-aquae on Human Natural Killer Cells. — Chapter 3.1 of the IBC Library Series, Volume 1911, Phytoceuticals: Examining the health benefit and pharmaceutical properties of natural antioxidants and phytochemicals
  15. ^ Spolaore P, Joannis-Cassan C, Duran E, Isambert A (February 2006). "Commercial applications of microalgae". Journal of Bioscience and Bioengineering. 101 (2): 87–96. doi:10.1263/jbb.101.87. PMID 16569602. 
  16. ^ Klamath Lake

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