Spatial and temporal patterns in microcystin toxins in Lake of the Woods surface waters

Zastepa, Arthur; Watson, Susan B.; Kling, Hedy; Kotak, Brian G.

doi:10.1080/10402381.2017.1384415

Cited by 22 publications

(12 citation statements)

References 21 publications

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“…MCs are hepatotoxic cyclic heptapeptides produced by several bloom-forming cyanobacteria belonging to several genera such as Microcystis , Nostoc , Oscillatoria , Planktothrix and Dolichospermum [ 8 , 9 , 10 , 11 , 12 , 13 ]. Owing to their ring structure, MCs are chemically stable under several field and laboratory conditions with half-life ranging from 0.4 to 22 days [ 14 , 15 , 16 , 17 , 18 , 19 ] and total concentrations varying from less than 1 µg·L −1 to 29,000 µg·L −1 in surface waters [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ]. Dissolved MCs in water bodies are recognized as a major public health hazard and disrupting agents of certain fundamental ecological processes [ 31 , 32 , 33 ].…”

Section: Introductionmentioning

confidence: 99%

Protective Role of Native Rhizospheric Soil Microbiota Against the Exposure to Microcystins Introduced into Soil-Plant System via Contaminated Irrigation Water and Health Risk Assessment

Redouane

Lahrouni²,

Martins³

et al. 2021

Toxins

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Microcystins (MCs) produced in eutrophic waters may decrease crop yield, enter food chains and threaten human and animal health. The main objective of this research was to highlight the role of rhizospheric soil microbiota to protect faba bean plants from MCs toxicity after chronic exposure. Faba bean seedlings were grown in pots containing agricultural soil, during 1 month under natural environmental conditions of Marrakech city in Morocco (March–April 2018) and exposed to cyanobacterial extracts containing up to 2.5 mg·L−1 of total MCs. Three independent exposure experiments were performed (a) agricultural soil was maintained intact “exposure experiment 1”; (b) agricultural soil was sterilized “exposure experiment 2”; (c) agricultural soil was sterilized and inoculated with the rhizobia strain Rhizobium leguminosarum RhOF34 “exposure experiment 3”. Overall, data showed evidence of an increased sensitivity of faba bean plants, grown in sterilized soil, to MCs in comparison to those grown in intact and inoculated soils. The study revealed the growth inhibition of plant shoots in both exposure experiments 2 and 3 when treated with 2.5 mg·L−1 of MCs. The results also showed that the estimated daily intake (EDI) of MCs, in sterilized soil, exceeded 2.18 and 1.16 times the reference concentrations (0.04 and 0.45 µg of microcysin-leucine arginine (MC-LR). Kg−1 DW) established for humans and cattle respectively, which raises concerns about human food chain contamination.

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Section: Introductionmentioning

confidence: 99%

Protective Role of Native Rhizospheric Soil Microbiota Against the Exposure to Microcystins Introduced into Soil-Plant System via Contaminated Irrigation Water and Health Risk Assessment

Redouane

Lahrouni²,

Martins³

et al. 2021

Toxins

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“…The specific objectives of this study were to (1) determine the distribution of microcystin congeners between sediment particles and pore waters in lake sediment cores; (2) estimate sediment deposition rates of microcystin congeners; and (3) determine whether sediments are a significant sink or source of microcystins to the overlying water, and whether there are congener-specific differences in these sediment-water diffusion fluxes. To achieve these objectives, we analyzed microcystins in sediment and pore waters from dated lake sediment cores from Lake of the Woods, Ontario, where toxic cyanobacterial blooms are pervasive (Chen et al 2007, Watson and Kling 2017, Zastepa et al 2017a).…”

mentioning

confidence: 99%

Distribution and flux of microcystin congeners in lake sediments

Zastepa

Blais

2017

Lake and Reservoir Management

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Sediment concentrations of microcystin congeners and exchange across the sediment-water interface were determined in Lake of the Woods, a large water body between Canada and the United States experiencing cyanobacterial blooms. Dated sediment cores were used to examine historical occurrence of microcystins and showed that microcystins were below detection prior to the 2000s. In more recent sediments the most abundant congeners were MC-LA and-LR with-RR,-YR,-7dmLR,-WR,-LF,-LY, and-LW also present. MC-LA and-LR were also distributed in the pore waters whereas MC-RR and-YR were more strongly adsorbed to sediment particles. Sediment burial rates for MC-LA and-LR were determined from the product of the microcystin concentration on sediment particles (ng/g dw) and the burial rate (based on 210 Pb radiochronology [g/m 2 /d]). Diffusion from sediments was estimated from the concentration gradient between pore water of surficial sediments and overlying water using Fick's first law. Overall, burial rates were low across sites (2.6 to 298.1 ng/m 2 /d) when compared to diffusion of microcystins from sediments to overlying water (303.1 to 1078.0 ng/m 2 /d) suggesting that sediments can be a source of microcystins to the water column. However, the relatively high diffusive flux may be short term and the result of a temporal disconnect between water column productivity and sediment processes. The higher diffusion fluxes and lower burial rates of MC-LA compared to MC-LR point to differences in environmental fate. Given that microcystin congeners vary in their toxicity, these results highlight the need for congener-specific measurements of environmental fate and persistence.

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“…Increasingly, studies have focused on microcystin regulation in situ, in particular through the incorporation of molecular techniques such as metatranscriptomics into field ecological studies, e.g., [28]. However, most studies that have measured microcystins in situ track the toxin at one location over long temporal scales, or if they have focused on spatial variability they have assessed total microcystins rather than determining microcystin quotas [29,30]. Examining microcystin quotas, rather than total microcystins, may allow greater insight into the variables that regulate production of the toxin.…”

Section: Introductionmentioning

confidence: 99%

Variability in microcystin quotas during a Microcystis bloom in a eutrophic lake

et al. 2021

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Microcystis is a bloom-forming genus of cyanobacteria with some genotypes that produce highly toxic microcystin hepatotoxins. In waterbodies where biological and physical factors are relatively homogenous, toxin quotas (the average amount of toxin per cell), at a single point in time, are expected to be relatively constant. In this study we challenged this assumption by investigating the spatial distribution of microcystin quotas at a single point in time on two separate occasions in a lake with a major Microcystis bloom. Microcystis cell concentrations varied widely across the lake on both sampling occasions (730- and 137-fold) together with microcystin quotas (148- and 362-fold). Cell concentrations and microcystin quotas were strongly positively correlated (R2 = 0.89, P < 0.001, n = 28; R2 = 0.67, P < 0.001, n = 25). Analysis of Microcystis strains using high-throughput sequencing of the 16S-23S rRNA intergenic spacer region showed no relationship between microcystin quota and the relative abundance of specific sequences. Collectively, the results of this study indicate an association between microcystin production and cell density that magnifies the potential for bloom toxicity at elevated cell concentrations.

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Spatial and temporal patterns in microcystin toxins in Lake of the Woods surface waters

Cited by 22 publications

References 21 publications

Protective Role of Native Rhizospheric Soil Microbiota Against the Exposure to Microcystins Introduced into Soil-Plant System via Contaminated Irrigation Water and Health Risk Assessment

Protective Role of Native Rhizospheric Soil Microbiota Against the Exposure to Microcystins Introduced into Soil-Plant System via Contaminated Irrigation Water and Health Risk Assessment

Distribution and flux of microcystin congeners in lake sediments

Variability in microcystin quotas during a Microcystis bloom in a eutrophic lake

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