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Management of Cyanobacteria and Cyanotoxins in Waters

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A special issue of Toxins (ISSN 2072-6651). This special issue belongs to the section "Marine and Freshwater Toxins".

Deadline for manuscript submissions: closed (20 October 2022) | Viewed by 28419

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Special Issue Editors

Dr. Arash Zamyadi

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Guest Editor

1. Research Manager (Position Hosted by Melbourne Water), Water Research Australia Limited, Adelaide, SA 5001, Australia
2. Senior Lecturer of Chemical Engineering, Department of Chemical Engineering, Faculty of Engineering and Information Technology, The University of Melbourne, Parkville, VIC 3010, Australia
Interests: wastewater treatment; water purification technologies; chlorine; disinfectants; cyanobacteria; water quality; civil engineering; water treatment; freshwater ecology
Special Issues, Collections and Topics in MDPI journals

Dr. Triantafyllos Kaloudis

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Guest Editor

Athens Water Supply & Sewerage Company, EYDAP SA, 11146 Athens, Greece
Interests: cyanotoxins; cyanobacterial metabolites; cyanobacterial blooms; detection/determination of cyanotoxins; mass spectrometry; water treatment; advanced oxidation processes; environmental chemistry
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear colleagues,

Cyanobacteria, also known as blue-green algae, are a diverse group of photosynthetic bacteria with the ability to colonise a range of environmental niches. They range in size from very small solitary cells to large visible colonies and are present in almost all aquatic habitats. Given the right environmental conditions, they can grow rapidly, forming blooms which impact the environment and a range of water uses. As a taxonomic group, cyanobacteria are capable of producing: (i) a large variety of bioactive compounds, including cyanotoxins, defined herein as compounds known to cause harm to humans or animals as a result of environmental exposure; for example, hepatotoxic microcystins and cylindrospermopsin, neurotoxic saxitoxins, anatoxins and BMAA (beta-Methylamino-L-alanine), and cytotoxins; (ii) a large variety of taste-and-odour (T&O) compounds, including the well-known compounds geosmin and MIB (2-methylisoberneol).

New research has demonstrated the breakthrough of cyanobacteria cells (both toxins and nontoxic cells) into water treatment plants. Even in low cell numbers this can lead to the accumulation of cells in plants, potentially leading to the breakthrough of combined chemical and/or microbial contaminants into treated water. Furthermore, the recent discovery of toxic benthic species and new toxins in drinking water and alternative water sources has raised concerns about the fate of cells and their potentially harmful metabolites, both at the source of the water and during the treatment processes. We are therefore inviting researchers across the globe to submit related ground-breaking work for review and publication in the Toxins Special Issue titled “Management of Cyanobacteria and Cyanotoxins in Waters”.

Dr. Arash Zamyadi
Dr. Triantafyllos Kaloudis
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a double-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Toxins is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (10 papers)

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Research

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15 pages, 3603 KiB

Open AccessEditor’s ChoiceArticle

Impact of Stagnation on the Diversity of Cyanobacteria in Drinking Water Treatment Plant Sludge

by Farhad Jalili, Hana Trigui, Juan Francisco Guerra Maldonado, Sarah Dorner, Arash Zamyadi, B. Jesse Shapiro, Yves Terrat, Nathalie Fortin, Sébastien Sauvé and Michèle Prévost

Toxins 2022, 14(11), 749; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins14110749 - 31 Oct 2022

Cited by 1 | Viewed by 1603

Abstract

Health-related concerns about cyanobacteria-laden sludge of drinking water treatment plants (DWTPs) have been raised in the past few years. Microscopic taxonomy, shotgun metagenomic sequencing, and microcystin (MC) measurement were applied to study the fate of cyanobacteria and cyanotoxins after controlled sludge storage (stagnation) in the dark in a full-scale drinking water treatment plant within 7 to 38 days. For four out of eight dates, cyanobacterial cell growth was observed by total taxonomic cell counts during sludge stagnation. The highest observed cell growth was 96% after 16 days of stagnation. Cell growth was dominated by potential MC producers such as Microcystis, Aphanocapsa, Chroococcus, and Dolichospermum. Shotgun metagenomic sequencing unveiled that stagnation stress shifts the cyanobacterial communities from the stress-sensitive Nostocales (e.g., Dolichospermum) order towards less compromised orders and potential MC producers such as Chroococcales (e.g., Microcystis) and Synechococcales (e.g., Synechococcus). The relative increase of cyanotoxin producers presents a health challenge when the supernatant of the stored sludge is recycled to the head of the DWTP or discharged into the source. These findings emphasize the importance of a strategy to manage cyanobacteria-laden sludge and suggest practical approaches should be adopted to control health/environmental impacts of cyanobacteria and cyanotoxins in sludge. Full article

(This article belongs to the Special Issue Management of Cyanobacteria and Cyanotoxins in Waters)

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13 pages, 1392 KiB

Open AccessArticle

Shotgun Metagenomic Sequencing to Assess Cyanobacterial Community Composition following Coagulation of Cyanobacterial Blooms

by Kim Thien Nguyen Le, Juan Francisco Guerra Maldonado, Eyerusalem Goitom, Hana Trigui, Yves Terrat, Thanh-Luan Nguyen, Barry Husk, B. Jesse Shapiro, Sébastien Sauvé, Michèle Prévost and Sarah Dorner

Toxins 2022, 14(10), 688; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins14100688 - 07 Oct 2022

Viewed by 1810

Abstract

The excessive proliferation of cyanobacteria in surface waters is a widespread problem worldwide, leading to the contamination of drinking water sources. Short- and long-term solutions for managing cyanobacterial blooms are needed for drinking water supplies. The goal of this research was to investigate the cyanobacteria community composition using shotgun metagenomics in a short term, in situ mesocosm experiment of two lakes following their coagulation with ferric sulfate (Fe₂(SO₄)₃) as an option for source water treatment. Among the nutrient paramenters, dissolved nitrogen was related to Microcystis in both Missisquoi Bay and Petit Lac St. François, while the presence of Synechococcus was related to total nitrogen, dissolved nitrogen, dissolved organic carbon, and dissolved phosphorus. Results from the shotgun metagenomic sequencing showed that Dolichospermum and Microcystis were the dominant genera in all of the mesocosms in the beginning of the sampling period in Missisquoi Bay and Petit Lac St. François, respectively. Potentially toxigenic genera such as Microcystis were correlated with intracellular microcystin concentrations. A principal component analysis showed that there was a change of the cyanobacterial composition at the genus level in the mesocosms after two days, which varied across the studied sites and sampling time. The cyanobacterial community richness and diversity did not change significantly after its coagulation by Fe₂(SO₄)₃ in all of the mesocosms at either site. The use of Fe₂(SO₄)₃ for an onsite source water treatment should consider its impact on cyanobacterial community structure and the reduction of toxin concentrations. Full article

(This article belongs to the Special Issue Management of Cyanobacteria and Cyanotoxins in Waters)

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15 pages, 2204 KiB

Open AccessArticle

Microcystin-LR Removal from Water via Enzymatic Linearization and Ultrafiltration

by Abelline Fionah, Cannon Hackett, Hazim Aljewari, Laura Brady, Faisal Alqhtani, Isabel C. Escobar and Audie K. Thompson

Toxins 2022, 14(4), 231; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins14040231 - 22 Mar 2022

Cited by 4 | Viewed by 3739

Abstract

Microcystin-LR (MC-LR) is a toxin produced by cyanobacteria that can bloom in freshwater supplies. This study describes a new strategy for remediation of MC-LR that combines linearization of the toxin using microcystinase A, MlrA, enzyme with rejection of linearized byproducts using membrane filtration. The MlrA enzyme was expressed in Escherichia coli (E. coli) and purified via a His-tag with 95% purity. Additionally, composite membranes made of 95% polysulfone and 5% sulfonated polyether ether ketone (SPEEK) were fabricated and used to filter a solution containing cyclic and linearized MC-LR. Tests were also performed to measure the adsorption and desorption of MC-LR on polysulfone/SPEEK membranes. Liquid chromatography-mass spectrometry (LC-MS) was used to characterize the progress of linearization and removal of MC-LR. Results indicate that the MlrA was successful at linearizing MC-LR. Membrane filtration tests showed rejection of 97% of cyclic MC-LR and virtually all linearized MC-LR, with adsorption to the membranes being the main rejection mechanism. Adsorption/desorption tests indicated that methanol could be used to strip residual MC-LR from membranes to regenerate them. This study demonstrates a novel strategy of remediation of microcystin-tainted water, combining linearization of MC-LR to a low-toxicity byproduct along with removal by membrane filtration. Full article

(This article belongs to the Special Issue Management of Cyanobacteria and Cyanotoxins in Waters)

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16 pages, 2170 KiB

Open AccessEditor’s ChoiceArticle

Warming and Salt Intrusion Affect Microcystin Production in Tropical Bloom-Forming Microcystis

by Bui Trung, Marlies E. Vollebregt and Miquel Lürling

Toxins 2022, 14(3), 214; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins14030214 - 16 Mar 2022

Cited by 1 | Viewed by 2297

Abstract

The Vietnamese Mekong Delta is predicted to be one of the regions most impacted by climate change, causing increased temperature and salinity in inland waters. We hypothesized that the increase in temperature and salinity may impact the microcystin (MC) production of two Microcystis strains isolated in this region from a freshwater pond (strain MBC) and a brackish water pond (strain MTV). The Microcystis strains were grown at low (27 °C), medium (31 °C), high (35 °C) and extremely high (37 °C) temperature in flat photobioreactors (Algaemist). At each temperature, when cultures reached a stable state, sea salt was added to increase salinity to 4‰, 8‰, 12‰ and 16‰. MC concentrations and cell quota were reduced at high and extremely high temperatures. Salinity, in general, had comparable effects on MC concentrations and quota. At a salinity of 4‰ and 8‰, concentrations of MC per mL of culture and MC cell quota (based on chlorophyll, dry-weight and particle counts) were higher than at 0.5‰, while at the highest salinities (12‰ and 16‰) these were strongly reduced. Strain MBC produced five MC variants of which MC-RR and MC-LR were most abundant, followed by MC-YR and relatively low amounts of demethylated variants dmMC-RR and dmMC-LR. In strain MTV, MC-RR was most abundant, with traces of MC-YR and dmMC-RR only in cultures grown at 16‰ salinity. Overall, higher temperature led to lower MC concentrations and cell quota, low salinity seemed to promote MC production and high salinity reduced MC production. Hence, increased temperature and higher salinity could lead to less toxic Microcystis, but since these conditions might favour Microcystis over other competitors, the overall biomass gain could offset a lower toxicity. Full article

(This article belongs to the Special Issue Management of Cyanobacteria and Cyanotoxins in Waters)

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18 pages, 2690 KiB

Open AccessArticle

First Report on Microcystin-LR Occurrence in Water Reservoirs of Eastern Cuba, and Environmental Trigger Factors

by José Carlos Rodríguez Tito, Liliana Maria Gomez Luna, Wim Noppe Noppe and Inaudis Alvarez Hubert

Toxins 2022, 14(3), 209; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins14030209 - 15 Mar 2022

Cited by 6 | Viewed by 2413

Abstract

The factors related to cyanotoxin occurrence and its social impact, with comprehension and risk perception being the most important issues, are not yet completely understood in the Cuban context. The objectives of this research were to determine the risk extension and microcystin-LR levels, and to identify the environmental factors that trigger the toxic cyanobacteria growth and microcystin-LR occurrence in 24 water reservoirs in eastern Cuba. Samplings were performed in the early morning hours, with in situ determination and physicochemical analysis carried out in the laboratory. Microcystin-LR were determined in water and within the cells (intracellular toxins) using UPLC–MS analysis after solid phase extraction. The reservoirs studied were found to be affected by eutrophication, with high levels of TN:TP ratio and phytoplankton cell concentrations, high water temperatures and low transparency, which cause collateral effect such as cyanobacterial bloom and microcystin-LR occurrence. In Hatillo, Chalóns, Parada, Mícara, Baraguá, Cautillo, La Yaya, Guisa and Jaibo reservoirs, concentrations of MC-LR higher than the WHO limits for drinking water (1 µg·L⁻¹), were detected. Full article

(This article belongs to the Special Issue Management of Cyanobacteria and Cyanotoxins in Waters)

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12 pages, 1313 KiB

Open AccessEditor’s ChoiceArticle

Different Algicidal Modes of the Two Bacteria Aeromonas bestiarum HYD0802-MK36 and Pseudomonas syringae KACC10292^T against Harmful Cyanobacteria Microcystis aeruginosa

by Bum Soo Park, Chong-Sung Park, Yuna Shin, Sungae Yoon, Myung-Soo Han and Yoon-Ho Kang

Toxins 2022, 14(2), 128; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins14020128 - 08 Feb 2022

Cited by 5 | Viewed by 2400

Abstract

Blooms of harmful cyanobacteria Microcystis aeruginosa lead to an adverse effect on freshwater ecosystems, and thus extensive studies on the control of this cyanobacteria’s blooms have been conducted. Throughout this study, we have found that the two bacteria Aeromonas bestiarum HYD0802-MK36 and Pseudomonas syringae KACC10292^T are capable of killing M. aeruginosa. Interestingly, these two bacteria showed different algicidal modes. Based on an algicidal range test using 15 algal species (target and non-target species), HYD0802-MK36 specifically attacked only target cyanobacteria M. aeruginosa, whereas the algicidal activity of KACC10292^T appeared in a relatively broad algicidal range. HYD0802-MK36, as a direct attacker, killed M. aeruginosa cells when direct cell (bacterium)-to-cell (cyanobacteria) contact happens. KACC10292^T, as an indirect attacker, released algicidal substance which is located in cytoplasm. Interestingly, algicidal activity of KACC10292^T was enhanced according to co-cultivation with the host cyanobacteria, suggesting that quantity of algicidal substance released from this bacterium might be increased via interaction with the host cyanobacteria. Full article

(This article belongs to the Special Issue Management of Cyanobacteria and Cyanotoxins in Waters)

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12 pages, 1168 KiB

Open AccessEditor’s ChoiceArticle

Comparative Assessment of Physical and Chemical Cyanobacteria Cell Lysis Methods for Total Microcystin-LR Analysis

by Katherine E. Greenstein, Arash Zamyadi and Eric C. Wert

Toxins 2021, 13(9), 596; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13090596 - 26 Aug 2021

Cited by 12 | Viewed by 3544

Abstract

Standardization and validation of alternative cell lysis methods used for quantifying total cyanotoxins is needed to improve laboratory response time goals for total cyanotoxin analysis. In this study, five cell lysis methods (i.e., probe sonication, microwave, freeze-thaw, chemical lysis with Abraxis QuikLyse^TM, and chemical lysis with copper sulfate) were assessed using laboratory-cultured Microcystis aeruginosa (M. aeruginosa) cells. Methods were evaluated for destruction of cells (as determined by optical density of the sample) and recovery of total microcystin-LR (MC-LR) using three M. aeruginosa cell densities (i.e., 1 × 10⁵ cells/mL (low-density), 1 × 10⁶ cells/mL (medium-density), and 1 × 10⁷ cells/mL (high-density)). Of the physical lysis methods, both freeze-thaw (1 to 5 cycles) and pulsed probe sonication (2 to 10 min) resulted in >80% destruction of cells and consistent (>80%) release and recovery of intracellular MC-LR. Microwave (3 to 5 min) did not demonstrate the same decrease in optical density (<50%), although it provided effective release and recovery of >80% intracellular MC-LR. Abraxis QuikLyse^TM was similarly effective for intracellular MC-LR recovery across the different M. aeruginosa cell densities. Copper sulfate (up to 500 mg/L Cu²⁺) did not lyse cells nor release intracellular MC-LR within 20 min. None of the methods appeared to cause degradation of MC-LR. Probe sonication, microwave, and Abraxis QuikLyse^TM served as rapid lysis methods (within minutes) with varying associated costs, while freeze-thaw provided a viable, low-cost alternative if time permits. Full article

(This article belongs to the Special Issue Management of Cyanobacteria and Cyanotoxins in Waters)

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Review

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24 pages, 2950 KiB

Open AccessReview

Evidence-Based Framework to Manage Cyanobacteria and Cyanotoxins in Water and Sludge from Drinking Water Treatment Plants

by Farhad Jalili, Saber Moradinejad, Arash Zamyadi, Sarah Dorner, Sébastien Sauvé and Michèle Prévost

Toxins 2022, 14(6), 410; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins14060410 - 15 Jun 2022

Cited by 7 | Viewed by 3026

Abstract

Freshwater bodies and, consequently, drinking water treatment plants (DWTPs) sources are increasingly facing toxic cyanobacterial blooms. Even though conventional treatment processes including coagulation, flocculation, sedimentation, and filtration can control cyanobacteria and cell-bound cyanotoxins, these processes may encounter challenges such as inefficient removal of dissolved metabolites and cyanobacterial cell breakthrough. Furthermore, conventional treatment processes may lead to the accumulation of cyanobacteria cells and cyanotoxins in sludge. Pre-oxidation can enhance coagulation efficiency as it provides the first barrier against cyanobacteria and cyanotoxins and it decreases cell accumulation in DWTP sludge. This critical review aims to: (i) evaluate the state of the science of cyanobacteria and cyanotoxin management throughout DWTPs, as well as their associated sludge, and (ii) develop a decision framework to manage cyanobacteria and cyanotoxins in DWTPs and sludge. The review identified that lab-cultured-based pre-oxidation studies may not represent the real bloom pre-oxidation efficacy. Moreover, the application of a common exposure unit CT (residual concentration × contact time) provides a proper understanding of cyanobacteria pre-oxidation efficiency. Recently, reported challenges on cyanobacterial survival and growth in sludge alongside the cell lysis and cyanotoxin release raised health and technical concerns with regards to sludge storage and sludge supernatant recycling to the head of DWTPs. According to the review, oxidation has not been identified as a feasible option to handle cyanobacterial-laden sludge due to low cell and cyanotoxin removal efficacy. Based on the reviewed literature, a decision framework is proposed to manage cyanobacteria and cyanotoxins and their associated sludge in DWTPs. Full article

(This article belongs to the Special Issue Management of Cyanobacteria and Cyanotoxins in Waters)

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25 pages, 1311 KiB

Open AccessFeature PaperEditor’s ChoiceReview

A Review of Cyanophage–Host Relationships: Highlighting Cyanophages as a Potential Cyanobacteria Control Strategy

by Christopher R. Grasso, Kaytee L. Pokrzywinski, Christopher Waechter, Taylor Rycroft, Yanyan Zhang, Alyssa Aligata, Michael Kramer and Anisha Lamsal

Toxins 2022, 14(6), 385; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins14060385 - 31 May 2022

Cited by 18 | Viewed by 4151

Abstract

Harmful algal blooms (HABs) are naturally occurring phenomena, and cyanobacteria are the most commonly occurring HABs in freshwater systems. Cyanobacteria HABs (cyanoHABs) negatively affect ecosystems and drinking water resources through the production of potent toxins. Furthermore, the frequency, duration, and distribution of cyanoHABs are increasing, and conditions that favor cyanobacteria growth are predicted to increase in the coming years. Current methods for mitigating cyanoHABs are generally short-lived and resource-intensive, and have negative impacts on non-target species. Cyanophages (viruses that specifically target cyanobacteria) have the potential to provide a highly specific control strategy with minimal impacts on non-target species and propagation in the environment. A detailed review (primarily up to 2020) of cyanophage lifecycle, diversity, and factors influencing infectivity is provided in this paper, along with a discussion of cyanophage and host cyanobacteria relationships for seven prominent cyanoHAB-forming genera in North America, including: Synechococcus, Microcystis, Dolichospermum, Aphanizomenon, Cylindrospermopsis, Planktothrix, and Lyngbya. Lastly, factors affecting the potential application of cyanophages as a cyanoHAB control strategy are discussed, including efficacy considerations, optimization, and scalability for large-scale applications. Full article

(This article belongs to the Special Issue Management of Cyanobacteria and Cyanotoxins in Waters)

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Other

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15 pages, 3384 KiB

Open AccessCase Report

Evaluating Ultrasonicator Performance for Cyanobacteria Management at Freshwater Sources

by Liam Vaughan, Dean Barnett, Elisa Bourke, Hamish Burrows, Fiona Robertson, Brad Smith, Jenna Cashmore, Michael Welk, Michael Burch and Arash Zamyadi

Toxins 2023, 15(3), 186; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins15030186 - 01 Mar 2023

Viewed by 1461

Abstract

Algal blooms consisting of potentially toxic cyanobacteria are a growing source water management challenge faced by water utilities globally. Commercially available sonication devices are designed to mitigate this challenge by targeting cyanobacteria-specific cellular features and aim to inhibit cyanobacterial growth within water bodies. There is limited available literature evaluating this technology; therefore, a sonication trial was conducted in a drinking water reservoir within regional Victoria, Australia across an 18-month period using one device. The trial reservoir, referred to as Reservoir C, is the final reservoir in a local network of reservoirs managed by a regional water utility. Sonicator efficacy was evaluated through qualitative and quantitative analysis of algal and cyanobacterial trends within Reservoir C and surrounding reservoirs using field data collected across three years preceding the trial and during the 18-month duration of the trial. Qualitative assessment revealed a slight increase in eukaryotic algal growth within Reservoir C following device installation, which is likely due to local environmental factors such as rainfall-driven nutrient influx. Post-sonication quantities of cyanobacteria remained relatively consistent, which may indicate that the device was able to counteract favorable phytoplankton growth conditions. Qualitative assessments also revealed minimal prevalence variations of the dominant cyanobacterial species within the reservoir following trial initiation. Since the dominant species were potential toxin producers, there is no strong evidence that sonication altered Reservoir C’s water risk profiles during this trial. Statistical analysis of samples collected within the reservoir and from the intake pipe to the associated treatment plant supported qualitative observations and revealed a significant elevation in eukaryotic algal cell counts during bloom and non-bloom periods post-installation. Corresponding cyanobacteria biovolumes and cell counts revealed that no significant changes occurred, excluding a significant decrease in bloom season cell counts measured within the treatment plant intake pipe and a significant increase in non-bloom season biovolumes and cell counts as measured within the reservoir. One technical disruption occurred during the trial; however, this had no notable impacts on cyanobacterial prevalence. Acknowledging the limitations of the experimental conditions, data and observations from this trial indicate there is no strong evidence that sonication significantly reduced cyanobacteria occurrence within Reservoir C. Full article

(This article belongs to the Special Issue Management of Cyanobacteria and Cyanotoxins in Waters)

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