Toxin Reviews ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/itxr20 An overview on cyanobacterial blooms and toxins production: their occurrence and influencing factors Isaac Yaw Massey , Muwaffak Al osman & Fei Yang To cite this article: Isaac Yaw Massey , Muwaffak Al osman & Fei Yang (2020): An overview on cyanobacterial blooms and toxins production: their occurrence and influencing factors, Toxin Reviews, DOI: 10.1080/15569543.2020.1843060 To link to this article: https://doi.org/10.1080/15569543.2020.1843060 Published online: 05 Nov 2020. Submit your article to this journal Article views: 6 View related articles View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=itxr20 TOXIN REVIEWS https://doi.org/10.1080/15569543.2020.1843060 REVIEW ARTICLE An overview on cyanobacterial blooms and toxins production: their occurrence and influencing factors Isaac Yaw Masseya, Muwaffak Al osmana and Fei Yanga,b aDepartment of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, Changsha, China; bDepartment of Occupational and Environmental Health, School of Public Health, University of South China, Hengyang, China ABSTRACT ARTICLE HISTORY Cyanobacteria are photosynthetic bacteria inhabiting water surface. They can increase to form a Received 26 January 2020 mass large enough, termed as cyanobacterial bloom. Cyanobacterial blooms can generate an Accepted 24 October 2020 array of harmful toxins, which may disturb water sources, subsequently posing frightful health KEYWORDS threat to living organisms. The occurrence of cyanobacterial blooms and cyanobacterial toxins Cyanobacteria; cyanobacter- are globally reported, mainly trigged by eutrophic conditions and climate change. The aim of ial blooms; cyanobacterial this review was to provide the current knowledge on cyanobacterial blooms and toxins produc- toxins; influencing factors tion; their occurrence and influencing factors. In addition this paper suggests some measures to ensure toxic blooms minimization. 1. Introduction cyanoblooms and cyanotoxins may contaminate water source, making it unsafe for ecological and human The most important natural resource essential for utilization. Thus the present review summarizes recent domestic, agriculture and industrial purposes is water. knowledge on cyanoblooms and cyanotoxins; their Consequently water should be save enough to be occurrence and influencing factors. This paper further consumed or utilized with low risk of immediate or puts forward some pressing measures to ensure toxic long term hazard, thus a vital issue to public health. cyanoblooms minimization. WHO (2011) demonstrated that cyanobacterial blooms (cyanoblooms) producing cyanobacterial toxins (cyano- toxins) are a fast growing water contamination source 2. Cyanobacteria and cyanobacterial blooms (further details are discussed under Cyanobacteria and The ancient cyanobacteria organisms, noticeable in cyanobacterial blooms, Cyanobacterial toxins, and rocks dating from the first thousand million years of Occurrence of cyanobacterial blooms and cyanobacter- the earth’s history and belong to the kingdom monera ial toxins). In addition various factors including natural (Prokaryota), division eubacteria and class cyanobac- and human-influenced may foster bloom occurrences teria (Ressom et al. 1994, Omidi et al. 2018), are a type and toxins production (further details are discussed in of photosynthetic bacteria that live in water surface. section 5). As cyanobacteria colonies occur in shallow water, they Water pollution resulting from cyanoblooms have appear in the fossil record in sedimentary rocks depos- globally been reported in oceans, lakes, rivers, ited in shallow seas and lakes. Cyanobacteria colonies lagoons, streams, wells and water reservoirs (Mowe identified as stromatolites emerge in rocks as fossilized et al. 2015, Ndlela et al. 2016, Meriluoto et al. 2017, mushroom shapes and sheets. Falconer (2005) Svircev et al. 2019, Zhang et al. 2019). Figure 1 illus- reported that the Gunflint chert was one of the best trates examples of cyanoblooms. The massive toxic stromatolite formations known in Lake Erie. It is of blooms of Microcystis sp. which occurred in Lake Taihu interest cyanobacteria was shown to possess a single and the western basin of Lake Erie, further producing circular chromosome completely sequenced in several microcystins affected water usage in Wuxi, China and species, plasmids and small circular strands of DNA Ohio, USA respectively for a period (Zhang et al. 2010, (Schwabe 1988, Kaneko et al. 1996). Whitton and Potts Carmichael and Boyer 2016). This suggests that (2000) found that the chlorophyll-a and pigment CONTACT Fei Yang [email protected] Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, Changsha, China ß 2020 Informa UK Limited, trading as Taylor & Francis Group 2 I. Y. MASSEY ET AL. Figure 1. Examples of bloom-forming cyanobacteria in China lakes; (A) Lake Taihu and (B) Dongfang hong pond. phycocyanin observed in cyanobacteria photosynthetic and crop yields (Runnegar et al. 1994, Sivonen and membranes were responsible for the characteristic Jones 1999, Osswald et al. 2007, Drobac et al. 2017, blue-green color of the many species. Pigments such Suleiman et al. 2017, Massey et al. 2018a, Alosman as carotenoids and phycoerythrin which give a strong et al. 2020). Animals and humans may be exposed to red color to some species may also be present the harmful effects of these toxins either through dir- (Bryant 1994). ect ingestion of cyanobacteria producing cells, con- It is well established that natural conditions sumption of contaminated water or body contact together with human-influenced activities enriching (Massey et al. 2018a, Cao et al. 2019a) and irrigation in water can rapidly increase to form a mass large the case of plants and crops (Drobac et al. 2017). enough that is visible to the naked eye. This phenom- enon is called cyanobloom (Mowe et al., 2015, Ndlela 3. Cyanobacterial toxins et al. 2016, Meriluoto et al. 2017, Svircev et al. 2019). Microcystis sp., Anabaena sp., Nostoc sp., The development of cyanoblooms has progressed to Cylindrospermopsis sp., and Planktothrix sp. are some promote natural compounds that are toxic to living of the common bloom-forming species. Occurrence of organisms. The toxins referred to as cyanotoxins exhibit toxic cyanoblooms is of great importance regarding animal, human, plant and crop toxicity. In this section the production of drinking water in both developed the most commonly reported cyanotoxins including and developing countries. This is due to the fact that, microcystin, nodularin, cylindrospermopsin, anatoxin-a presence of toxic cyanoblooms in drinking water sour- and saxitoxin (Sivonen and Jones 1999, Mowe et al., ces may reduce the water quality and create potential 2015, Ndlela et al. 2016,Meriluotoet al. 2017,Svircev risk of toxin exposure for water consumers which have et al. 2019) were reviewed. Cyanotoxins such as guani- become a global health concern (Runnegar et al. 1994, toxin (formerly anatoxin-a(s)), BMAA and lipopolysac- Sivonen and Jones 1999, Osswald et al. 2007, charides were not considered in this section. Suleiman et al. 2017, Massey et al. 2018a, Zhang et al. 2019). Further the oxygen depletion induced may 3.1. Microcystin result to hypoxia and anoxia in aquatic animals and vegetations (Rabalais et al. 2010). Health threats occur The most frequently reported cyanotoxin globally when dense accumulation of cyanobacteria cells found in freshwaters, marine habitats and desert envi- appears on water surface. This is the period where ronments is cyclic heptapeptide hepatotoxin microcys- death and lysis of bacteria cells result to the release of tin. Species of cyanobacteria including Microcystis, toxins in the watershed consequently destroying the Anabaena, Planktothrix, Nostoc, and Cylindrospermopsis quality of drinking water, by giving it an unpleasant can produce this toxin (Metcalf et al. 2012, Ma and Li taste and smell (Falconer 1999). Researchers demon- 2018, Massey et al. 2018a, 2018b, Yang et al. 2018a, strated that the occurrence of these toxins have 2020). Microcystin was named after Microcystis aerugi- caused a number of animal poisoning and deaths, nosa, the cyanobacterium in which the toxin was ini- posed great threat to human health and affected plant tially isolated and described (Carmichael et al. 1988). TOXIN REVIEWS 3 Bishop et al. (1959) originally identified microcystin as 3.2. Nodularin Fast-Death Factor which was subsequently renamed Nodularin is a group of cyclic pentapeptide hepato- by Konst et al. (1965). Currently over 270 microcystin toxin that consists of five variable amino acids. variants have been isolated from cyanoblooms Nodularin mostly produced by Nodularia spumigena, (Bouaicha et al. 2019, Massey et al. 2020a), with the Nostoc and Iningainema (Scytonemataceae) are widely most widespread and acutely toxic being MC-LR, MC- disseminated around the subtropical and temperate RR and MC-YR (Liu et al. 2018, Yang et al. 2018b, 2020, regions, and are primarily found in coastal sea and Massey et al. 2020b). Microcystins share a common freshwater (McGregor and Sendall 2017). The chemical genetic structure cyclo-(-D-Ala1-L-X2-D-MeAsp3-L- structure of nodularin molecule is cyclo-(D-MeAsp1-L- Z4-Adda5-D-Glu6-Mdha7). Adda is (2S, 3S, 8S, 9S) Arg2-Adda3-DGlu4-Mdhb5),