Klamath Lake AFA

A hand holding dense clumps of Aphanizomenon flos-aquae in water
Upper Klamath Lake AFA

Aphanizomenon flos-aquae harvested from Upper Klamath Lake in Oregon, or simply Klamath Lake AFA or Klamath AFA, is a cyanobacterial biomass that has been harvested wild from Upper Klamath Lake since the 1980s for use in dietary supplements.[1][2] Small amounts of A. flos-aquae can be found in bodies of water worldwide,[3] but it is notable for growing prolifically in Upper Klamath Lake in Oregon.

The primary strain is Aphanizomenon flos-aquae MDT14a.[4][5] Ap. flos-aquae was historically treated as a single homogeneous species, but genome sequencing has revealed significant diversity within the group, with some subgroups more appropriately categorized as distinct species.[6] Average nucleotide identity comparison identifies MDT14a as belonging to the same genomic species as strain LD13 (MDT13), also isolated from the Upper Klamath Lake, at 99.29% ANI.[7][4]: 92 

Taxonomy

The classification of Aphanizomenon flos-aquae has undergone significant taxonomic revision in light of recent genomic studies that have revealed substantial genetic variability, leading to the identification of distinct strains found around the world.[3] These advancements have clarified a longstanding misconception regarding toxin production in Ap. flos-aquae samples from Upper Klamath Lake. Earlier studies attributed the presence of cyanotoxins such as microcystin and cylindrospermopsin directly to production by Ap. flos-aquae. However, genome sequencing and species-specific analysis has revealed that Klamath AFA is incapable of producing microcystins or other toxins,[8][7][9] but were instead the result of cross-contamination from co-occurring toxin-producing cyanobacteria living in the same environment, most commonly with species of Microcystis.[10]

The following cyanobacteria of the "Anabaena, Dolichospermum, and Aphanizomenon" (ADA) clade have been isolated from Upper Klamath Lake, with their full genomes sequenced:[7]

Depositor nomenclatureDriscoll cladeGTDB nomenclature[a]
Anabaena sp. MDT14bADA-2Dolichospermum lemmermannii[11]
Ap. flos-aquae MDT14aADA-4"Dolichospermum flosaquae"[12]
Ap. flos-aquae LD13ADA-4"Dolichospermum flosaquae"[13]

None of the three above strains carry any toxin biosynthetic genes.[4]: 99  None of the ADA-4 strains tested (the two above, WA113 from Cranberry Lake, and WA102 from Anderson Lake) carry any toxin-producing genes.[4]: 99 

Habitat

Upper Klamath Lake in the Cascade Range of south-central Oregon hosts a viable and harvestable population of Ap. flos-aquae, primarily the strain Ap. flos-aquae MDT14a.[14]

Klamath Lake's high levels of dissolved minerals, large surface area, shallow depths, and other nutritional and environmental factors create suitable conditions for the proliferation of Ap. flos-aquae.[15] Some of these factors are the lake's high 4,100 feet (1,259 m) elevation,[16] eutrophic nutrient levels,[17] high alkalinity (8.5 pH or higher),[18] a large surface area of 96 square miles with an average depth of 8 feet,[16] and nearly 300 sunny days per year.[19]

Product recalls

Cross-contamination of products containing Klamath AFA have occurred in the past. From 2018 to 2020, the Food and Drug Administration did three product recalls, all by the same original harvesting company.[20][21][22] Each recall found higher levels of microcystin than suggested by the WHO and EPA provisional guidelines, which is less than 1 microgram per gram.[23] These investigations led to Class 2 voluntary recalls of the affected products. The products were all linked to several batches of AFA harvested by the company between 2015 and 2017. From these recalls, the FDA started working with harvesting companies to outline new industry practices and testing procedures for harvesting AFA.[24] These now include:

  1. At the time of harvest, examining AFA at the harvesting site for contaminating cyanobacteria.
  2. At the time of harvest, testing the water and AFA for microcystins.
  3. After harvest, testing the AFA slurry for microcystins.
  4. Before selling AFA products, testing each lot or batch for microcystins.
  5. Using more than one test method to confirm results.
  6. Using a test method that can detect multiple variant forms of microcystins.
  7. Using certified testing laboratories and validated methods.
  8. Providing a certificate of analysis to purchasers for each lot or batch sold.

Since these guidelines were developed, no product recalls have occurred. As of 2024, the FDA states that wild-harvested cyanobacteria is safe to eat.[25]

See also

References

  1. ↑ See Aphanizomenon flos-aquae § Genomes for a discussion of the status of GTDB "Dolichospermum flosaquae".
  1. ↑ "Import Health Standard: Stored Plant Products for Human Consumption". Plant Imports and Biosecurity of New Zealand. Ministry for Primary Industries, New Zealand. 2023-05-25. p. 31. 5.14 Algal therapeutic supplement live preparations for Aphanizomenon flos-aquae;
  2. ↑ "Licensed Klamath Lake AFA health products registered in Canada". Health-Products.Canada.ca.
  3. 1 2 Scoglio, Gabriel D.; Jackson, Harry O.; Purton, Saul (2024-08-01). "The commercial potential of Aphanizomenon flos-aquae, a nitrogen-fixing edible cyanobacterium". Journal of Applied Phycology. 36 (4): 1593–1617. Bibcode:2024JAPco..36.1593S. doi:10.1007/s10811-024-03214-0. ISSN 1573-5176. 122 different AFA strains have been reported based on morphological and phylogenetic analyses, and have been isolated from sites around the world... North America, Asia, and all across Europe, from Portugal and Spain to the Baltic Sea and Scandinavia.
  4. 1 2 3 4 Driscoll, Connor B. Comparative Genomics of Freshwater Bloom-Forming Cyanobacteria and Associated Organisms. ir.library.oregonstate.edu (Ph.D. thesis). Retrieved 2024-12-02.
  5. ↑ Underwood, Jennifer C; Hall, Natalie C; Mumford, Adam C; Harvey, Ronald W (2024-05-01). "Relation between the relative abundance and collapse of Aphanizomenon flos-aquae and microbial antagonism in Upper Klamath Lake, Oregon". FEMS Microbiology Ecology. 100 (5) fiae043. doi:10.1093/femsec/fiae043. PMC 11022654. PMID 38533659.
  6. ↑ Rajaniemi, Pirjo; Hrouzek, Pavel; Kaštovská, Klára; Willame, Raphaël; Rantala, Anne; Hoffmann, Lucien; Komárek, Jiří; Sivonen, Kaarina (1 January 2005). "Phylogenetic and morphological evaluation of the genera Anabaena, Aphanizomenon, Trichormus and Nostoc (Nostocales, Cyanobacteria)". International Journal of Systematic and Evolutionary Microbiology. 55 (1): 11–26. doi:10.1099/ijs.0.63276-0.
  7. 1 2 3 Driscoll, C.B.; Meyer, K.A.; Sulcius, S.; Brown, N.M.; Dick, G.J.; Cao, H.; Gasiunas, G.; Timinskas, A.; Yin, Y.; Landy, Z.C.; Otten, T.G.; Davis, T.W.; Watson, S.B.; Dreher, T.W. (2018). "A closely-related clade of globally distributed bloom-forming cyano-bacteria within the Nostocales". Harmful Algae. 77: 93–107. Bibcode:2018HAlga..77...93D. doi:10.1016/j.hal.2018.05.009. PMID 30005805.
  8. ↑ Burdick, S. M. (July 2020). "Effects of harmful algal blooms and associated water-quality on endangered Lost River and shortnose suckers". Harmful Algae. 97 101847. Bibcode:2020HAlga..9701847B. doi:10.1016/j.hal.2020.101847. PMID 32732045.
  9. ↑ Carmichael, W.W.; Drapeau, C.; Anderson, D.M. (2000-12-01). "Harvesting of Aphanizomenon flos-aquae Ralfs ex Born. & Flah. var. os-aquae (Cyanobacteria) from Klamath Lake for human dietary use". Journal of Applied Phycology. 12 (6): 585–595. Bibcode:2000JAPco..12..585C. doi:10.1023/A:1026506713560 – via Springer Nature.
  10. ↑ Scoglio, Gabriel D.; Jackson, Harry O.; Purton, Saul (2024-08-01). "The commercial potential of Aphanizomenon flos-aquae, a nitrogen-fixing edible cyanobacterium". Journal of Applied Phycology. 36 (4): 1593–1617. Bibcode:2024JAPco..36.1593S. doi:10.1007/s10811-024-03214-0. ISSN 1573-5176. Aphanizomenon flos-aquae typically cohabits with other cyanobacteria, most commonly Microcystis species: mainly M. aeruginosa, Dolichospermum/Anabaena flos-aquae and Gloeotrichia echinulate.
  11. ↑ "GCA_001672195.1". gtdb.ecogenomic.org.
  12. ↑ "GTDB - GCA_001672095.1". gtdb.ecogenomic.org.
  13. ↑ "GTDB - GCA_001672165.1". gtdb.ecogenomic.org.
  14. ↑ Scoglio, Gabriel D.; Jackson, Harry O.; Purton, Saul (2024-08-01). "The commercial potential of Aphanizomenon flos-aquae, a nitrogen-fixing edible cyanobacterium". Journal of Applied Phycology. 36 (4): 1593–1617. Bibcode:2024JAPco..36.1593S. doi:10.1007/s10811-024-03214-0. ISSN 1573-5176. The AFA biomass used for commercial products is exclusively harvested from the wild; specifically from Klamath Lake in Oregon, USA.
  15. ↑ Baker, J.P. "Water Quality Conditions in Upper Klamath and Agency Lakes, Oregon, 2006". pubs.usgs.gov. U.S. Geological Survey. Retrieved 2024-12-06. The lake's large surface area and shallow depths contribute to its high nutrient concentrations, fostering AFA blooms.
  16. 1 2 "Upper Klamath Lake: The Largest Lake in Oregon". Lakepedia. 2024. Retrieved 24 April 2026. Elevation: 1259 meters
  17. ↑ "Causes and Effects of Nutrient Conditions in the Upper Klamath River" (PDF). PacifiCorp. November 2006. The extreme abundance of chlorophyll, and the growth of phytoplankton are a natural consequence of the occurrence of excess nutrients...
  18. ↑ "Water and Endangered Fish in the Klamath River Basin". Oregon Water Science Center. 2023-01-01. Retrieved 2016-12-20. High pH values observed in Upper Klamath Lake have been associated with algal photosynthesis during the rapid early growth phase of the A. flos-aquae blooms...often greater than 9.5.
  19. ↑ "History of Klamath Falls". City of Klamath Falls. 2026. Retrieved 24 April 2026.
  20. ↑ "Beverage with AFA Product Recall". FDA. 2020-12-10.
  21. ↑ "AFA Supplement Capsules Recalled". FDA. 2018-08-07.
  22. ↑ "AFA Capsules Supplement, Product Recall". FDA. 2018-07-27.
  23. ↑ Schaeffer, David J.; Malpas, Phyllis B.; Barton, Larry L. (1999-09-01). "Risk Assessment of Microcystin in Dietary Aphanizomenon flos-aquae". Ecotoxicology and Environmental Safety. 44 (1): 73–80. Bibcode:1999EcoES..44...73S. doi:10.1006/eesa.1999.1816. ISSN 0147-6513. PMID 10499991.
  24. ↑ Program, Human Foods (2024-09-09). "Blue-Green Algae Products and Microcystins". FDA.
  25. ↑ "Natural Toxins in Food". US Food and Drug Administration. 26 September 2024. Retrieved 6 December 2024.
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