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Small and shallow water bodies are particularly sensitive to adverse conditions connected with anthropogenic eutrophication. As model systems, ponds are a good object for ecological research and monitoring of global environmental changes. We examined cyanobacteria along with other groups of algae versus zooplankton and abiotic characteristics of water in 51 aquatic ecosystems exposed to anthropogenic pressure (from natural forest to highly disturbed field ponds) with 3 distinct trophic groups: meso-, eu- and hypertrophic. This study aimed to define how different levels of trophy affect pond-specific cyanobacteria assemblages and to identify species responding to particular trophic states. We demonstrated that trophic type determined the occurrence of certain cyanobacteria species. From among 78 identified taxa, shade- and turbid mixed adapted were the most numerous. Eutrophic ponds had the highest cyanobacteria species and diversity and abundance of zooplankon. Dominating species such as Chroococcus minimus, Anagnostidinema amphibium, Phormidium granulatum or Komvophoron minutum preferred mesotrophic, while e.g. Jaaginema subtilissimum, Limnolyngbya circumcreta, Limnothrix vacuolifera or Romeria leopolienis eutrophic waters and these were not grazed by filtrators. Only 3 species (Aphanizomenon flos-aquae, Dolichospermum circinale, Planktothrix agardhii) were associated with hypertrophic ponds. Therefore, we assume that cyanobacteria taxa have a high indicative potential to distinguish between trophic type of ponds. Reynolds Functional Groups also exhibit responses to changes in water quality. It was partucularly evident in the case of cyanobacteria representatives of codon M which was attributed to eutrophic ponds. Advancing our understanding about trophic preferences of cyanobacteria is crucial, especially in the era of global warming and the persistent issue of water eutrophication, when problems with harmful cyanobacterial blooms are intensifying. The research findings have ecological significance and management implications, highlighting the often-overlooked importance of pond ecosystems in maintaining overall water quality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Control of algal blooms and associated biologically-induced water quality risks in drinking reservoirs is problematic. Copper sulphate (CuSO 4 ) treatment is one intervention that has been utilised for >100 years. Evidence indicates a favourable short-term reduction in Cyanobacterial biomass (e.g. bloom termination), but here we indicate that it may also increase longer-term water quality risk. In 2022, we investigated the impacts of CuSO 4 spraying on Cyanobacterial communities and nutrient levels within a drinking water supply reservoir using environmental DNA (eDNA) to assess community shifts, alongside monitoring nutrient fractions, orthophosphate (OP) and total phosphate (TP), post-treatment. CuSO 4 application successfully reduced Cyanobacterial abundance, however elimination of Cyanobacteria resulted in a shift in bacterial dominance favouring Planctomycetota throughout the summer and a combination of Actinobacteriota and Verrucomicrobiota, throughout autumn. As Cyanobacterial abundance recovered post-treatment, Cyanobacterial genera demonstrated greater diversity compared to only three Cyanobacterial genera present across samples pre-treatment, and included taxa associated with water quality risk (e.g. taste and odour (T&O) metabolite and toxin producers). The increase in Cyanobacteria post-treatment was attributed to an increase in biologically available nutrients, primarily a significant increase in OP. Overall, findings suggest that the significant shift in biodiversity likely induces a less stable ecosystem with greater plasticity of response to changing environmental and biogeochemical variables. Legacy implications of CuSO 4 spraying, in terms of shifts in ecosystem and nutrient balance over time, may have implications for drinking water quality, but importantly also for reservoir management options. As such, the effects of CuSO 4 spraying should be considered carefully before consideration as a contender for in-reservoir biological control., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Crown Copyright © 2024. Published by Elsevier Ltd. All rights reserved.)

Water quality of eutrophic lakes is threatened by harmful cyanobacterial blooms, which are favored by summer heatwaves and expected to intensify with global warming. Societal demands on surface water for drinking, irrigation and recreation are also highest in summer, especially during dry and warm conditions. Here, we analyzed trends in online searches to investigate how public awareness of cyanobacterial blooms is impacted by temperature in nine different countries over almost twenty years. Our findings reveal large seasonal and interannual variation, with more online searches for harmful cyanobacteria in temperate regions during hot summers. Online searches and media attention increased even more steeply with temperature than the incidence of cyanobacterial blooms, presumably because lakes attract more people during warm weather. Overall, our study indicates that warmer summers not only increase cyanobacterial bloom incidence, but also lead to a pronounced increase of the public awareness of toxic cyanobacterial blooms., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

While algal blooms occur frequently in lakes and reservoirs worldwide, the effects of dissolved organic matter (DOM) from lakeside and riparian zones on bloom formation are not well understood. In this study, we characterized the molecular composition of DOM from Cynodon dactylon (L.) Pers. (CD-DOM) and Xanthium sibiricum Patrin ex Widder (XS-DOM) and assessed their effects on the growth, physiology, volatile organic compounds (VOCs), and stable carbon isotope in four bloom-forming algae species (Microcystis aeruginosa, Anabaena sp., Chlamydomonas sp., and Peridiniopsis sp.). Stable carbon isotope analysis showed that the four species were affected by DOM. Both DOM types increased the cell biomass, polysaccharide and protein contents, chlorophyll fluorescence parameter values, and VOCs release of Anabaena sp., Chlamydomonas sp. and Microcystis aeruginosa, suggesting that DOM stimulated algal growth by increasing nutrient sources, photosynthetic efficiency, and stress tolerance. And in general, these three strains exhibited better growth at higher DOM concentrations. However, DOM treatment inhibited the growth of Peridiniopsis sp., as indicated by the increases in reactive oxygen species, damage in photosystem II reaction centers, and blockage in electron transport. Fluorescence analysis showed that tryptophan-like compounds were the main DOM components that affected algal growth. Molecular-level analysis suggested that unsaturated aliphatic compounds may be the most important DOM components. The findings indicate that CD-DOM and XS-DOM promote the blue-green algal blooms formation and thus should be considered in the management of natural water quality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Harmful cyanobacterial blooms plague reservoirs and lakes used for a variety of purposes, such as recreation and drinking water. Chemical controls are frequently used to mitigate the occurrence of cyanobacterial blooms given that many are fast-acting and effective at reducing cyanobacterial abundance. Recent research has identified hydrogen peroxide (H 2 O 2 ) as an environmentally friendly alternative to algaecides that have typically been used, such as copper sulfate. To build on past studies, these experiments sought to further understand how well H 2 O 2 treatments reduce cyanobacteria in complex eutrophic conditions, as well as to assess treatment effects on a non-target phytoplankter, a green alga. We assessed the effectiveness of H 2 O 2 (at treatments of 2-16 mg L -1 ) under varying environmental conditions in a controlled laboratory setting, including (1) dissolved organic matter (DOM) concentrations (humic acid; 0-60 mg L -1 ), (2) temperature (20, 25, and 32 °C), and (3) initial algal biomass (chlorophyll-a; 82-371 µg L -1 ). In contrast to our expectations, neither DOM concentration nor temperature meaningfully impacted the effectiveness of H 2 O 2 at reducing cyanobacteria. However, initial algal biomass as well as H 2 O 2 treatment dose greatly influenced the effectiveness of the algaecide on cyanobacteria. Treatments of ≥ 8 mg H 2 O 2 L -1 on algal biomass were significantly buffered with higher DOM and lower temperature, and the biological significance of these findings should be explored further. Across all experiments, H 2 O 2 concentrations of 0.03-0.12 mg H 2 O 2 L -1  µg chlorophyll L -1 were effective at significantly reducing cyanobacteria with varying effects on algal biomass. Thus, water resource managers are encouraged to consider how ambient levels of phytoplankton biomass may affect the ability of H 2 O 2 to control cyanobacterial blooms prior to treatment., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

In recent years, the consumption of blue-green algae (BGA) dietary supplements is increasing because of their health benefits. However, cyanobacteria can produce cyanotoxins, which present serious health risks. In this work we propose hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry (HILIC-MS/MS) to determine cyanotoxins in BGA dietary supplements. Target toxins, including microcystin-leucine-arginine (MC-LR) and microcystin-arginine-arginine (MC-RR), nodularin, anatoxin-a and three non-protein amino acids, β-N-methylamino-L-alanine (BMAA), 2,4-diaminobutyric acid (DAB) and N-(2-aminoethyl)glycine (AEG), were separated using a SeQuant ZIC-HILIC column. Cyanotoxin extraction was based on solid-liquid extraction (SLE) followed by a tandem-solid phase extraction (SPE) procedure using Strata-X and mixed-mode cation-exchange (MCX) cartridges. The method was validated for BGA dietary supplements obtaining quantification limits from 60 to 300 µg·kg -1 . Nine different commercial supplements were analyzed, and DAB, AEG, and MCs were found in some samples, highlighting the relevance of monitoring these substances as precaution measures for the safe consumption of these products.

The demand for nanoparticles is increasing tremendously, and so is the risk of their foreseeable discharge into the environment. Nanoparticles contain a variety of features, including anti-microbial properties, and have been shown to have toxic effects on aquatic organisms previously. However, the causes of nanoparticle toxicity under environmental conditions are still unknown. Exposure to nanoparticles in the environment is unavoidable as nanomaterials are used more prevalent in our daily lives, and as a result, nanotoxicity research is gaining traction. To understand the impact of nanoparticle toxicity on aquatic biota, cyanobacteria (blue-green algae) are an ideal model system. The cyanobacteria play an important role in ecological balance, nutrient cycling, energy flow, biological nitrogen fixation, and environmental remediation, and their susceptibility to nanoparticles can help in making a wise strategy for the mitigation of possible nano-pollution. This article presents an analysis of recent research findings on the toxicological influences of nanoparticles on the growth rate, biochemical changes, ultra-structural changes as well as the nanoparticle toxicity mechanisms in cyanobacteria. The finding suggests that the shading effect, generation of reactive oxygen species, membrane damage and disintegration of pigments are the main reasons for nanoparticle toxicity to the cyanobacteria., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The recently described genus Rhizonema is among the most important cyanobacterial partners in lichen symbioses, but its morphological characterization in the genus diagnosis-true branching of the T-type-appears at odds with several published figures showing false branching. We investigated cyanobiont branching and cell division with light microscopy in two basidiolichens from Florida and one from Japan, including aposymbiotically cultured material of the latter. Mycobiont species identities (Cyphellostereum jamesianum, Dictyonema darwinianum, and D. moorei) and photobiont genus identity (Rhizonema) were corroborated with ITS and rbcLX sequences, respectively. Single and paired false branching occurred commonly in all three strains examined. False branches developed adjacent to necridic cells or heterocytes, or by separation of vegetative cells at compression folds in the trichome. Non-transverse cell divisions, usually oblique, were observed in two of the three Rhizonema strains examined. T-type true branches sometimes arose from such divisions, although oblique growth from the branch cell often resulted in ambiguous branch junctions. Additionally, Y-type true branches appeared to grow from contorted filaments. In cultured material, a kind of pseudo-branch sometimes arose from single- or several-celled segments liberated from trichome apices. The segments attached secondarily to filaments and grew there as apparent branches. We conclude that Rhizonema is a genus of considerable morphological flexibility, with multiple modes of branching possible in a single strain. While true branching or non-transverse divisions, when observable, may help distinguish Rhizonema from the phenotypically similar Scytonema, false branching occurs commonly in both genera, and therefore cannot be used to distinguish them., (© 2022 Phycological Society of America.)

Cyanobacteria are good candidates for various martian applications as a potential source of food, fertilizer, oxygen, and biofuels. However, the increased levels of highly toxic perchlorates may be a significant obstacle to their growth on Mars. Therefore, in the present study, 17 cyanobacteria strains that belong to Chroococcales, Chroococcidiopsidales, Nostocales, Oscillatoriales, Pleurocapsales, and Synechococcales were exposed to 0.25-1.0% magnesium perchlorate concentrations (1.5-6.0 m M ClO 4 - ions) for 14 days. The exposure to perchlorate induced at least partial inhibition of growth in all tested strains, although five of them were able to grow at the highest perchlorate concentration: Chroococcidiopsis thermalis , Leptolyngbya foveolarum , Arthronema africanum , Geitlerinema cf. acuminatum , and Cephalothrix komarekiana . Chroococcidiopsis sp. Chroococcidiopsis cubana /carotenoids ratio tended to be decreased. The results show that selected cyanobacteria from different orders can tolerate perchlorate concentrations typical for the martian regolith, indicating that they may be useful in Mars exploration. Further studies are required to elucidate the biochemical and molecular basis for the perchlorate tolerance in selected cyanobacteria.a /carotenoids ratio tended to be decreased. The results show that selected cyanobacteria from different orders can tolerate perchlorate concentrations typical for the martian regolith, indicating that they may be useful in Mars exploration. Further studies are required to elucidate the biochemical and molecular basis for the perchlorate tolerance in selected cyanobacteria.

Lake sediment and algal sludge with large output posed significant environmental risks. In this work, an idea of co-utilization of both solid wastes for the production of ceramsite (a sort of porous lightweight aggregates as building materials) was proposed and validated for the first time. The treatment process contained a dewatering step by a flocculation-pressure filtration method, and a sintered ceramsite preparation step. Effects of flocculant type and dosage on the dewatering performance were studied in the first step. An environmental-friendly amphoteric starch flocculant with a dosage of 12 mg/(g dried sample) was found to achieve the best dewatering performance. Effects of raw material mass ratio, sintering temperature and time in the second step were investigated. Under the optimal conditions (60 wt% of dewatered sediment; 20 wt% of dewatered algal sludge; 20 wt% of additives (fly ash: calcium oxide: kaolin = 2:1:2); sintering temperature: 1100 °C; time: 35 min), the obtained ceramsite met the Chinese National Standard as a qualified building material, with reliable environmental safety according to the leaching results for both heavy metals and microcystins. Both environmental and economic benefits of the proposed treatment were assessed. The process completely followed the rules of "reduction, harmlessness and resource utilization" for solid waste treatment and disposal; Meanwhile, the profit of the proposed ceramsite production could be more than 2.3 US dollar/m 3 . The co-utilization method in this work acted as a good example for the comprehensive management of solid wastes in water-rich areas., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Cyanobacterial biomass has constituted a crucial third and fourth-generation biofuel material, with great potential to synthesize a wide range of metabolites, mainly carbohydrates. Lately, carbohydrate-based biofuels from cyanobacteria, such as bioethanol, biohydrogen, and biobutanol, have attracted attention as a sustainable alternative to petroleum-based products. Cyanobacteria can perform a simple process of saccharification, and extracted carbohydrates can be converted into biofuels with two alternatives; the first one consists of a fermentative process based on bacteria or yeasts, while the second alternative consists of an internal metabolic process of their own in intracellular carbohydrate content, either by the natural or genetic engineered process. This study reviewed carbohydrate-enriched cyanobacterial biomass as feedstock for biofuels. Detailed insights on technical strategies and limitations of cultivation, polysaccharide accumulation strategies for further fermentation process were provided. Advances and challenges in bioethanol, biohydrogen, and biobutanol production by cyanobacteria synthesis and an independent fermentative process are presented. Critical outlook on life-cycle assessment and techno-economical aspects for large-scale application of these technologies were discussed., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: There is no financial or personal interest that is potential competing interest to declare., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Macrophytes have often been considered as a prospective tool for the elimination of cyanobacterial bloom, because they may produce chemical compounds that outcompete bloom-forming cyanobacteria. However, a comprehensive, unbiased overview of evidence to support this is missing. Moreover, studies into the effects of individual macrophyte species have often used different methodologies and, thus, cannot be compared. Herein, we firstly carried out a systematic review of studies into the effects of macrophytes on the growth of bloom-forming cyanobacteria. Secondly, we carried out an experiment into the effects of aqueous and ethanol extracts from 19 macrophyte species on the growth of two of the most common cyanobacteria, Aphanizomenon gracile and Microcystis aeruginosa, using a uniform methodological approach. The systematic review revealed that most of the 69 macrophyte species previously studied have shown a combination of inhibitory, stimulatory, and neutral effects. In our own experiment, an inhibitory effect was exhibited only 15 times out of 532 experimental variants, specifically by Chara globularis, Ceratophyllum submersum, Elodea nuttallii, Hydrilla verticillata, Myriophyllum heterophyllum, M. spicatum, and Vallisneria americana. Put together, these results indicate that the practical application of chemical compounds produced by macrophytes to eliminate cyanobacterial bloom may have lower prospects than previously anticipated., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

In the past decades, the intensity and duration of cyanobacterial blooms are increasing due to anthropogenic factors. These phenomena worry drinking water companies and water managers because cyanobacteria produce a diverse range of cyanotoxins, which can cause liver, digestive and neurological diseases. The main exposure routes for humans are the consumption of drinking water that has not been effectively treated and the recreational use of polluted waters. For risk assessment and to conduct studies on large-scale occurrence, the development of reliable but simple, sensitive and cost-effective analytical approaches able to cover a wide range of cyanotoxins is essential. Additionally, the determination of intracellular and extracellular toxins separately is advantageous for risk management. To the best of our knowledge, this is the first time that a method for the multi-class determination of cyanotoxins in fresh water, which is able to separately report intra- and extracellular toxins, meet the criteria of simplicity (not requiring multiple sample preparation procedures or time-consuming steps) and it is based on highly specific high resolution mass spectrometry (potential for wide screening and retrospective analysis). Matrix effects, trueness and precision met general validation criteria for a group of nine cyanotoxins, including anatoxins, cylindrospermopsin and microcystins. Considering a 50 mL sample, the method quantification limits were within the range of 8-45 ng L -1 and 25-129 ng L -1 for intra- and extracellular cyanotoxins, respectively. Anatoxin-a, cylindrospermopsin and some microcystins were found in three out of four Dutch lakes included in the study, at concentrations up to 52 μg L -1 ., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The cyanobacterial oligopeptides are recognized for being highly selective, efficacious and relatively safer compounds with diverse bioactivities. Azoline-based natural compounds consist of heterocycles which are reduced analogues of five-membered heterocyclic azoles. Among other varieties of azoline-based natural compounds, the heteropeptides bearing oxazoline or thiazoline heterocycles possess intrinsic structural properties with captivating pharmacological profiles, representing excellent templates for the design of novel therapeutics. The specificity of heteropeptides has been translated into prominent safety, tolerability, and efficacy profiles in humans. These peptidic congeners serve as ideal intermediary between small molecules and biopharmaceuticals based on their typically low production complexity compared to the protein-based biopharmaceuticals. The distinct bioproperties and unique structures render these heteropeptides one of the most promising lead compounds for drug discovery. The high degree of chemical diversity in cyanobacterial secondary metabolites may constitute a prolific source of new entities leading to the development of new pharmaceuticals. This review focuses on the azoline-based natural oligopeptides with emphasis on distinctive structural features, stereochemical aspects, biological activities, structure activity relationship, synthetic and biosynthetic aspects as well as mode of action of cyanobacteria-derived peptides., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Taste and odor episodes caused by off-flavor secondary metabolites, such as 2-methylisoborneol (MIB) and geosmin, pose one of the greatest challenges for drinking water utilities around the world. The prevalence of these compounds is predicted to increase in the future as a function of nutrient enrichment and elevated temperatures of surface drinking water sources. We conducted a manipulative field experiment in a drinking water reservoir to elucidate patterns for two taste and odor compounds, MIB and geosmin, as well as two taxa known to produce these compounds, phytoplankton (more specifically, cyanobacteria) and actinobacteria, across different depths in response to nutrient enrichment with two common dissolved nitrogen forms, organic urea or inorganic nitrate. In general, we found that MIB levels increased by greater than 250% with nutrient enrichment mediated by increased phytoplankton biomass. However, the effect of the fertilization treatments on MIB decreased with depth with a 35% reduction at 7 m versus 1.5 m. In contrast, geosmin levels reached a maximum at the lowest measured depth (7 m), were unaffected by the fertilization treatments, and followed a similar pattern to the abundance of actinobacteria. Thus, our data suggest that the positive response of phytoplankton (e.g., cyanobacteria, such as Oscillatoria species) to the fertilization treatments is likely responsible for increased MIB, while geosmin concentrations may be a function of actinobacteria-mediated decomposition in the hypolimnion in our study system.

A high incidence of harmful algal bloom in eutrophic surface waters causes many environmental problems. Thermophilic aerobic composting enables effective treatment and disposal of algal sludge that remains after the dewatering of algae slurries, and provides a value-added organic fertiliser. Previous studies have either only dealt with the composting of a single waste component or were conducted at a lab-/pilot-scale; however, this work is a comprehensive assessment of full-scale mechanized thermophilic aerobic co-composting of algal sludge and other typical biomass-based wastes, including chicken faeces and rice straw, in a water-rich rural area in the Tai lake basin, China. With the optimised feedstock material mass ratio (6.0:1.8:1.0 for straw:algae:faeces; initial C/N ratio of 20; and initial moisture of 60 wt%), the co-composting process effectively achieved the reduction, harmlessness, and reuse of waste. The moisture content (28.36 wt% of wet weight), organic matter content (57.91 wt% of dried weight), total nutrient content (6.59 wt% for TN + TP + TK of dried weight), and heavy metal contents as well as the pH of the final product fully met the Chinese National Agricultural Organic Fertiliser Standard requirements. The reduction rates of microcystin and toxic volatile fatty acid contents were higher than 99.5%, and the seed germination index of the product was 114.5%. A notable economic benefit with a gross profit margin of 167-434% of the process was highlighted. Investigation of the associated mechanisms, including statistical analysis, spectral characterisation, micro-morphological observation, and microbial community analysis, revealed that a decreased particle sizes with a looser structure and an efficient humification effect, resulting from the work of several identified dominant microbial species, contributed to the high product quality. The current study provided a demonstration of the promising full-scale co-composting technology for comprehensive management of the environment in water-rich rural areas and the construction of a sustainable watershed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Cyanobacteria or blue-green algae are becoming increasingly abundant in North American fresh water lakes. Toxins produced by cyanobacteria have been associated with gastrointestinal injury, liver failure, and nephrotoxicity. They have also been implicated in the pathogenesis of gastrointestinal and liver cancers. The purpose of the present study was to determine whether the incidence rates of gastrointestinal, liver, and urologic cancers are increasing in the province of Manitoba and, if so, whether these increases spatially and/or temporally correlate with areas where cyanobacterial contamination of fresh water lakes have been identified. Cancer incidence data were obtained from the Manitoba Cancer Registry. Cyanobacterial contamination data, as reflected by microcystin toxin concentrations, were available from the Manitoba Water Stewardship. ArcGIS mapping was employed to document spatial and temporal relationships between cancer incidence and cyanobacterial data. The results revealed that although the incidence rates for all three cancers have increased over the past 20-25 years, these increases were not disproportionally higher in zones with high microcystin toxin determinations. The results of this study argue against increased exposure to cyanotoxins as an explanation for the increase in gastrointestinal, liver and urologic cancers in Manitoba.

Cyanobacteria harmful blooms (CyanoHABs) in lakes and reservoirs represent a major risk for water authorities globally due to their toxicity and economic impacts. Anticipating bloom occurrence and understanding the main drivers of CyanoHABs are needed to optimize water resources management. An extensive review of the application of CyanoHABs forecasting and predictive models was performed, and a summary of the current state of knowledge, limitations and research opportunities on this topic is provided through analysis of case studies. Two modelling approaches were used to achieve CyanoHABs anticipation; process-based (PB) and data-driven (DD) models. The objective of the model was a determining factor for the choice of modelling approach. PB models were more frequently used to predict future scenarios whereas DD models were employed for short-term forecasts. Each modelling approach presented multiple variations that may be applied for more specific, targeted purposes. Most models reviewed were site-specific. The monitoring methodologies, including data frequency, uncertainty and precision, were identified as a major limitation to improve model performance. A lack of standardization of both model output and performance metrics was observed. CyanoHAB modelling is an interdisciplinary topic and communication between disciplines should be improved to facilitate model comparisons. These shortcomings can hinder the adoption of modelling tools by practitioners. We suggest that water managers should focus on generalising models for lakes with similar characteristics and where possible use high frequency monitoring for model development and validation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Degradation of lake conditions could result from many stressors generated by human disturbance. Accurately defining lake ecological condition by multimetric index (MMI) method is of great importance for tracking source of stressors and lake management. For algal assessment, seldom have structural and functional attributes of soft-bodied planktonic algae metrics, one important dimension of biological condition, been used to develop MMI in conjunction with diatom metrics. Another thing is that some researchers found MMI method does not perform well in mid- and high-disturbed lakes. To test the aforementioned questions, we used data sets of the 2007 National Lake Assessment project of the USEPA to develop MMIs with and without using soft-bodied planktonic algae metrics for plains and lowlands area (PLNLOW, high disturbed region of the US) and across the conterminous US. Compared to site groups modeled by single diatom assemblages, we found integrating soft-bodied planktonic algae metric (especially blue-green algae metric) into developing MMIs can significantly improve performance of MMI in PLNLOW region. The separation powers of MMIs of five level III ecoregions, developed by incorporating blue-green algae metric, are consistently higher than those developed by single diatom assemblages (p-value = 0.029). However, when blue-green algae metric was applied to develop MMI along with diatom metrics in the national scale assessment, performances of MMIs are similar to that developed by diatom metrics (0.14 < p-value < 0.86). Different performance of MMIs developed by integrating blue-green algae metric at different spatial scales indicated the usefulness of blue-green algae metric in ecological assessment in mid- and high- disturbed lakes and a tiered approach for using diatom and blue-green algae metric in ecological assessment. We suggest using blue-green algae metric in combined with diatom metric to develop MMI when lakes are mid- and high-disturbed, while a routine diatom assessment would be enough for minimally disturbed sites., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The potential usage of cyanobacteria and microalgae as a promising and alternative source for new and safe therapeutic compounds is recently caught the attention, due to its versatile properties as antitumor, antioxidant, antifungal, and antiviral agents. Primarily, the cyanobacteria and microalgae from fresh and marine water are previously studied, however those isolated from soil and agriculture drain water were poorly investigated. Therefore, this study aimed to screen and characterize the antioxidant profile, as well as the potential anticancer assessment of 12 species of cyanobacteria and two species of microalgae strains isolated from soil and agriculture drain water. The data showed that total phenol contents were highest in Anabaena oryzae and Aphanizomenon gracile (27.39 and 26.83 mg GAE/g, respectively), followed by Leptolyngbya fragilis (22.96 mg GAE/g). Out of the 14 species identified, the cyanobacterium Dolichospermum flos-aquae HSSASE2 exhibited the most elevated antioxidant activity in terms of NO scavenging activity and anti-lipid peroxidation potential (IC 50  = 28.7 ± 0.1 and 11.9 ± 0.2 μg/ml, respectively) and the lowest DPPH radical scavenging activity (467.7 μg/ml). Screening of the anticancer potential of all studied strains against four different human cancer cell lines (Caco-2, MCF-7, PC3, and HepG-2) demonstrated that Dolichospermum crassum HSSASE20 has the highest anticancer effect among all tested species against colon and prostate cancer cell lines (IC 50  = 57.9 ± 0.4 and 44.1 ± 0.2 μg/ml, respectively), while Oscillatoria sancta HSSASE19 recorded the most anticancer effect against MCF-7 (breast cancer) cell line (IC 50  = 15.1 ± 0.7 μg/ml). Dolichospermum spiroides HSSASE18 obtained the highest anticancer effect HepG-2 (hepatic cancer) cell line (IC 50  = 48.8 ± 0.7 μg/ml). Additionally, cytotoxicity against healthy peripheral blood mononuclear cells was studied and revealed that Oscillatoria sancta was the safest one among all studied strains. Data obtained from the sensitivity index demonstrated that Dolichospermum crassum was the most sensitive strain against the four cancerous cell lines. Cyanobacteria and microalgae from the soil and drain water sources are efficient free radical scavengers, containing apoptogens capable of stimulating apoptotic cascades and overcoming chemo-resistance in cancer therapy. Thus, these novel secondary metabolites are an excellent alternative, safe, and low-cost antioxidant and anticancer therapeutic compounds.

The growth of cyanobacteria (blue-green algae) is a typical phenomenon in water bodies worldwide. The use of silver carp (Hypophthalmichthys molitrix) to reduce excessive phytoplankton development is controversial. In the case of cyanobacteria, many of which are toxic, understanding their possible digestion mechanism by fish is particularly desirable. A unique methodical approach, which consists of applying intestinal contents or extracts to a cyanobacteria culture, was used. Unicellular cyanobacteria (Cyanothece) were incubated in vitro with bile, contents of different parts of the intestinal tract, and cytosolic and microsomal extracts of the intestinal tissue of silver carp. The abundance of cyanobacteria decreased in all treatments containing either exclusively bile or its combination with intestinal contents. This research provides the first evidence of non-mechanical digestion of cyanobacteria by silver carp. Cyanobacteria incubated with intestinal contents or extracts reached mostly higher abundances than those incubated with the nutrient medium. The existence of non-mechanical digestion mediated via intestinal contents and extracts or its compensation connected with organic substance uptake is discussed.

A redefinition of the cyanobacterial lineage has been proposed based on phylogenomic analysis of distantly related nonphototrophic lineages. We define Cyanobacteria here as "Organisms in the domain bacteria able to carry out oxygenic photosynthesis with water as an electron donor and to reduce carbon dioxide as a source of carbon, or those secondarily evolved from such organisms.", (© 2019 The Authors. Journal of Phycology published by Wiley Periodicals, Inc. on behalf of Phycological Society of America.)

Bioreductive capabilities of four morphologically different strains of cyanobacteria have been assessed in this work. Arthrospira maxima, Leptolyngbya foveolarum, Nodularia sphaerocarpa and Synechococcus bigranulatus were applied as catalysts for the reduction of acetophenone to the corresponding chiral phenylethyl alcohol. The process was modified regarding substrate concentration, duration of pre-cultivation period, duration of biotransformation, light regime and glucose addition to the culture media. Obtained results clearly showed that cyanobacteria were active towards acetophenone what resulted in the substrate reduction to (S)-1-phenylethanol with high enantiomeric excess. The reaction efficiency increased with the biotransformation time, but the higher concentration of substrate limited the process yield. Also, all tested strains performed reaction with the highest efficacy under continuous light regime. The most active strains - N. sphaerocarpa and S. bigranulatus carried out the conversion of 1 mM acetophenone with high efficiency of respectively 97.6% and 96.2% after 13 days of biotransformation. A. maxima reached 45.8% of conversion after 13 days of biotransformation whereas L. foveolarum did not exceed 20%. The enantiomeric excesses were respectively 98.8%- A. maxima, 91.7%- L. foveolarum, 72.6%- S. bigranulatus and N. sphaerocarpa 16.2%., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Cyanobacteria are known to produce a wide variety of bioactive, toxic secondary metabolites generally described as hepatotoxins, neurotoxins, cytotoxins, or dermatoxins. In Brazil, the regular monitoring of cyanobacterial toxins has intensified after the death of 65 patients in a hemodialysis clinic in Caruaru in the state of Pernambuco due to microcystin exposure. The primary objective of this study was to use multivariate statistics that incorporated environmental parameters (both biotic and abiotic) to forecast blooms of cyanobacteria and their toxic secondary metabolites in 20 drinking water reservoirs managed by the Water Treatment Company of Ceará (CAGECE) in the semi-arid region of Ceará, Brazil. Across four years (January 2013 to January 2017), 114 different phytoplankton taxa were identified, including 24 cyanobacterial taxa. In general, Ceará reservoirs were dominated by cyanobacteria due to eutrophication but also because of the dry and warm climate found throughout the region. Interestingly, specific cyanobacterial taxa were influenced by different biotic and abiotic factors. For example, nitrogen-to-phosphorus (N:P) and evaporation were positively related to saxitoxin-producing taxa, especially Raphidiopsis raciborskii, while temperature, electrical conductivity, total phosphorus, and transparency (measured as Secchi depth) were positively associated with microcystin-producing taxa, such as Microcystis aeruginosa. Climate forecasts predict higher evaporation and temperatures in the semi-arid Ceará region, which will likely magnify droughts and water scarcity as well as promote toxic cyanobacterial blooms in reservoirs in the future. Therefore, understanding the factors associated with algal blooms dominated by specific taxa is paramount for water resource management., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Cyanobacteria are an important component of microalgae communities in aquatic ecosystems, however, their response to environmental factors in different habitats and catchment areas of small water bodies is still not well recognised. We examined ponds from two types of surroundings (field vs. forest) in order to find the best triggers for the distribution of cyanobacteria species, and analysed different habitats (open water and macrophyte-dominated zones) to find the habitat preferences of cyanobacteria species. Our results underline the important role of habitats in the determination of the abundance of cyanobacteria species in small water bodies. Cyanobacteria as a group preferred macrophyte-dominated sites with stable water column conditions, which to lesser extent were inhabited by representatives of other systematic groups of algae. The co-occurrence of many cyanobacteria species and zooplankton in the studied ponds may have indirectly resulted from biotic interactions in the food web. In the open water a positive relationship between zooplankton and cyanobacteria suggests stimulation of their development through the elimination of smaller edible taxa or by nutrient resupply through zooplankton excretion. The type of catchment area also impacted the cyanobacterial community. Field ponds with significantly higher values of pH and NO 3 were characterised by a higher abundance of cyanobacteria compared with ponds within the forest catchment. A positive relationship between pH and cyanobacteria indicates that they raise pH during photosynthesis. However, some species were negatively associated with water temperature and occurred exclusively only in forest ponds. The study revealed that cyanobacteria in small water bodies can be a valuable indicator of important ecosystem conditions. Despite the fact that their prevalence in agricultural ponds may confirm their potential as an indicator of pollution, their high diversity associated with macrophytes contributes to an increase of overall landscape biodiversity., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The hazardous effects of current nanoparticle synthesis methods have steered researchers to focus on the development of newer environmentally friendly and green methods for synthesizing nanoparticles using nontoxic chemicals. The development of environmentally friendly methods of nanoparticle synthesis with different sizes and shapes is one of the pressing challenges for the current nanotechnology. Several novel green approaches for the synthesis of AuNPs have been explored using different natural sources, such as plants, algae, bacteria, and fungi. Among organisms, algae and blue-green algae are of particular interest for nanoparticle synthesis. Gold nanoparticles (AuNPs) have a range of applications in medicine, diagnostics, catalysis, and sensors because of their significant key roles in important fields. AuNPs have attracted a significant interest for use in a variety of applications. The widespread use of AuNPs can be accredited to a combination of optical, physical, and chemical properties as well as the miscellany of size, shape, and surface composition that has been adopted through green synthesis methods.

The Blue Lagoon is a geothermal aquifer with a diverse ecosystem located within the Reykjanes UNESCO Global Geopark on Iceland's Reykjanes Peninsula. Blue Lagoon Ltd., which exploits the aquifer, isolated a strain of coccoid cyanobacteria Cyanobacterium aponinum (C. aponinum) from the geothermal fluid of the Blue Lagoon more than two decades ago. Since then Blue Lagoon Ltd. has cultivated it in a photobioreactor, for use as an active ingredient in its skin care products. Until recently, the cultivation of C. aponinum was achieved by feeding it on 99.99% (4N) bottled carbon dioxide (CO 2 ). In this investigation, C. aponinum was cultivated using unmodified, non-condensable geothermal gas (geogas) emitted from a nearby geothermal powerplant as the feed-gas instead of the 4N-gas. The geogas contains roughly 90% vol CO 2 and 2% vol hydrogen sulfide (H 2 S). A comparison of both CO 2 sources was made. It was observed that the use of geogas did enhance the conversion efficiency. A 13 weeks' average CO 2 conversion efficiency of C. aponinum was 43% and 31% when fed on geogas and 4N-gas, respectively. Despite the high H 2 S concentration in the geogas, sulfur accumulation in the cultivated biomass was similar for both gas sources. Our results provide a model of a CO 2 sequestration by photosynthetic conversion of otherwise unused geothermal emission gas into biomass.

Carotenoids from cyanobacteria Aphanothece microscopica Nageli and green microalgae Chlorella vulgaris and Scenedesmus obliquus were identified. The total carotenoid content, based on dry weight of biomass, of A. microscopica Nägeli, C. vulgaris and S. obliquus were 1398.88μg/g, 1977.02μg/g and 2650.70μg/g, respectively. A total of 23 different carotenoids were separated in all the extracts, the major ones being all-trans-β-carotene (29.3%) and all-trans-lutein (28.1%) in Scenedesmus; all-trans-echinenone (22.8%) and all-trans-β-carotene (17.7%) in Chlorella; all-trans-echinenone (28.3%) and all-trans-β-carotene (26.2%) in Aphanothece. The carotenoid extracts were shown to be a potent scavenger of peroxyl radical, with values of 31.1 (Chlorella), 14.0 (Scenedesmus) and 7.3 (Aphanothece) times more potent than α-tocopherol., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Cyanobacterial blooms are a potential health hazard due to the ability of some species to produce toxins that are harmful to other living organisms. This review provides a comprehensive summary of anecdotal and case reports on acute poisonings in animals and humans attributable to cyanotoxin exposure in fresh- and brackish-waters. Approximately two-thirds of reported poisonings have occurred in Europe and the United States. Dogs and livestock account for the majority of reported cases involving animal exposure to cyanotoxins, while recreational activities are responsible for approximately half of reported incidents involving human exposure. Due to data limitations it is difficult to estimate the total number of animals and humans affected by cyanotoxins, however, some general observations regarding frequency and numbers affected are made. The review demonstrates that cyanotoxins have, and will likely to continue to have, potentially serious consequences for public health and animal welfare worldwide., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The cyanobacteria are well recognized as producers of a wide array of bioactive metabolites including toxins, and potential drug candidates. However, a limited number of taxa are generally considered with respect to both of these aspects. That said, the order Stigonematales, although largely overlooked in this regard, has become increasingly recognized as a source of bioactive metabolites relevant to both human and environmental health. In particular, the hapalindoles and related indole alkaloids (i.e., ambiguines, fischerindoles, welwitindolinones) from the order, represent a diverse, and phylogenetically characteristic, class of secondary metabolites with biological activity suggestive of potential as both environmental toxins, and promising drug discovery leads. The present review gives an overview of the chemical diversity of biologically active metabolites from the Stigonematales-and particularly the so-called hapalindole-type alkaloids-including their biosynthetic origins, and their pharmacologically and toxicologically relevant bioactivities. Taken together, the current evidence suggests that these alkaloids, and the associated cyanobacterial taxa from the order, warrant future consideration as both potentially harmful (i.e., "toxic") algae, and as promising leads for drug discovery.

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous detection and quantitation of seven microcystin congeners (1-7) and nodularin-R (8) in blue-green algal dietary supplements. Single-laboratory method validation data were collected in four supplement matrices (capsule, liquid, powder, and tablet) fortified at toxin concentrations from 0.25-2.00 μg/g (ppm). Average recoveries and relative standard deviations (RSD) using matrix-corrected solvent calibration curves were 101% (6% RSD) for all congeners and supplements investigated. Limits of detection (0.006-0.028 μg/g) and quantitation (0.018-0.084 μg/g) were sufficient to confirm the presence of microcystin contamination at the Oregon-mandated guidance concentration of 1.0 μg of microcystin-LReq/g. Quantitated concentrations of microcystin contamination in market-available Aphanizomenon flos-aquae blue-green algal supplements ranged from 0.18-1.87 μg of microcystin-LReq/g for detected congeners microcystin-LR, microcystin-LA, and microcystin-LY (3-5). Microcystin-RR, -YR, -LW, and -LF and nodularin-R (1, 2, and 6-8) were not detected in the supplements examined.

Background: The incidence of liver cancer has been increasing in Canada over the past decade, as has cyanobacterial contamination of Canadian freshwater lakes and drinking water sources. Cyanotoxins released by cyanobacteria have been implicated in the pathogenesis of liver cancer., Objective: To determine whether a geographic association exists between liver cancer and surrogate markers of cyanobacterial contamination of freshwater lakes in Canada., Methods: A negative binomial regression model was employed based on previously identified risk factors for liver cancer., Results: No association existed between the geographic distribution of liver cancer and surrogate markers of cyanobacterial contamination. As predicted, significant associations existed in areas with a high prevalence of hepatitis B virus infection, large immigrant populations and urban residences., Discussion and Conclusions: The results of this study suggest that cyanobacterial contamination of freshwater lakes does not play an important role in the increasing incidence of liver cancer in Canada.

Lake Erie, the world's tenth largest freshwater lake by area, has had recurring blooms of toxic cyanobacteria for the past two decades. These blooms pose potential health risks for recreation, and impact the treatment of drinking water. Understanding the timing and distribution of the blooms may aid in planning by local communities and resources managers. Satellite data provides a means of examining spatial patterns of the blooms. Data sets from MERIS (2002-2012) and MODIS (2012-2014) were analyzed to evaluate bloom patterns and frequencies. The blooms were identified using previously published algorithms to detect cyanobacteria (~25,000 cells mL-1), as well as a variation of these algorithms to account for the saturation of the MODIS ocean color bands. Images were binned into 10-day composites to reduce cloud and mixing artifacts. The 13 years of composites were used to determine frequency of presence of both detectable cyanobacteria and high risk (>100,000 cells mL-1) blooms. The bloom season according to the satellite observations falls within June 1 and October 31. Maps show the pattern of development and areas most commonly impacted during all years (with minor and severe blooms). Frequencies during years with just severe blooms (minor bloom years were not included in the analysis) were examined in the same fashion. With the annual forecasts of bloom severity, these frequency maps can provide public water suppliers and health departments with guidance on the timing of potential risk.

Cyanobacteria contain various types of bioactive compounds, which could cause adverse effects on organisms. They are released into surface waters during cyanobacterial blooms, but there is little information on their potential relevance for effects in vivo. In this study presence of bioactive compounds was characterized in cyanobacteria Microcystis aeruginosa (Chroococcales), Planktothrix agardhii (Oscillatoriales) and Aphanizomenon gracile (Nostocales) with selected in vitro assays. The in vivo relevance of detected bioactivities was analysed using transgenic zebrafish embryos tg(cyp19a1b-GFP). Teratogenic potency was assessed by analysis of developmental disorders and effects on functions of the neuromuscular system by video tracking of locomotion. Estrogenicity in vitro corresponded to 0.95-54.6 ng estradiol equivalent(g dry weight (dw))(-1). In zebrafish embryos, estrogenic effects could not be detected potentially because they were masked by high toxicity. There was no detectable (anti)androgenic/glucocorticoid activity in any sample. Retinoid-like activity was determined at 1-1.3 μg all-trans-retinoic acid equivalent(g dw)(-1). Corresponding to the retinoid-like activity A. gracile extract also caused teratogenic effects in zebrafish embryos. Furthermore, exposure to biomass extracts at 0.3 gd wL(-1) caused increase of body length in embryos. There were minor effects on locomotion caused by 0.3 gd wL(-1)M. aeruginosa and P. agardhii extracts. The traditionally measured cyanotoxins microcystins did not seem to play significant role in observed effects. This indicates importance of other cyanobacterial compounds at least towards some species or their developmental phases. More attention should be paid to activity of retinoids, estrogens and other bioactive substances in phytoplankton using in vitro and in vivo bioassays., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Monoterpenes are widely used in food technology, cosmetic and pharmaceutical industries and as compounds of agricultural importance. It is known that compounds comprising this class can be transformed by a variety of organisms, namely by: bacteria, fungi, yeasts, plants or isolated enzymes. Biotransformations, as one of the most important tools of green chemistry, allow obtaining new products using whole cells of micro-organisms or isolated enzymes in mild reaction conditions. Therefore, biotransformations of monoterpenes, by different type of reaction such as: epoxidation, oxidation and stereoselective hydroxylation, resulted in the production of so desired, enantiomerically defined compounds that can be advised as natural seem to be interesting. Bearing in mind that such processes are carried out also by easy to maintain, photoautotrophic micro-organisms cultivated at large scale, this paper is focused on biotransformations of acyclic, monocyclic and bicyclic monoterpenes by freshwater or haliphylic cyanobacteria and microalgae on the way of mainly stereoselective hydroxylation. Moreover, aspects of potential industrial application of obtained products in medicine, perfume, cosmetics and food industry are discussed., (© 2014 The Society for Applied Microbiology.)

The phenomenon of cyanobacterial bloom, among other things, is chronic and periodic pollution, which is mainly caused by phosphorus and nitrogen, as well as high temperatures and direct sunlight. To carry out this experiment, in order to obtain blooming cyanobacteria in the warm water pond fish, water samples were taken from 5 farms and after purification, mass culture of 4 species of cyanobacteria that had the highest density was prepared. Then kaolin with a concentration of 0.5 g/liter and separately with two sizes of 50 and 100 micrometers was added to the pure culture of any cyanobacteria species using a 1-meter column. The amount of reduction of cyanobacteria was checked by counting by Neubauer chamber at 0, 3, 9 and 24 hours after adding to it. The results showed the decrease in the number of cyanobacteria Chroococcus sp. For kaolin with two sizes of 100 and 50 micrometers, it was 24.4 and 39%, respectively. This rate was 25.8 and 15.5% for the cyanobacterium Gloeocapsa sp. Also, for cyanobacterium Oscillatoria sp., 23.5 and 35.3% were calculated and finally for cyanobacterium Microcystis sp., 29.4 and 33.3% were calculated. The results of this research showed that the separate use of two sizes of kaolin, 100 and 50 micrometers, is effective for the immediate control of cyanobacterial bloom, and also, comparing the two sizes of kaolin, kaolinite with the size of 50 micrometers had better operation. [ABSTRACT FROM AUTHOR]

Heavy metals such as mercury (Hg) can cause disturbances in the metabolic and phycoremediation activities of microalgae. γ-aminobutyric acid or GABA is a non-protein amino acid and has a signaling role that can regulate the homeostasis of reactive oxygen species (ROS) under environmental stress. In this research, the effect of exogenous GABA on the physiological responses of blue-green algae (cyanobacterium) Spirulina platensis under mercury stress was investigated. HgCl2 in 4 and 8 μM, and GABA in 2 and 4 mM, individually and as a combined treatment, were applied to the microalgal cell suspensions for 48 hours. Then, the indices; dry weight, chlorophyll a, carotenoid, phycobilins, phenol, carbohydrate, protein, malondialdehyde, and polyphenol oxidase and peroxidase activities were evaluated. HgCl2 treatment (individually) decreased dry weight, chlorophyll a, carotenoid, phycoerythrin, phenol, carbohydrate and protein compared to those in control and increased the level of lipid peroxidation and the activities of polyphenol oxidase and peroxidase enzymes. Single treatment of GABA increased dry weight, phycobilin, phenol, malondialdehyde, protein and enzyme activity. But the combined treatments (GABA + HgCl2) improved most of the physiological indices. HgCl2 treatment in one or both concentrations caused a negative effect on the physiological indicators of Spirulina platensis and decreased metabolites such as phenol and proteins, but GABA treatment in most cases reduced the negative effects of mercury and improved the indices. According to the literature, Hg toxicity can be caused by disrupting the biosynthesis of photosynthetic pigments and the activity of enzymes and the occurrence of oxidative stress. While, exogenous GABA can improve the metabolic and physiological cell condition as a signaling molecule through the occurrence of some intracellular events. [ABSTRACT FROM AUTHOR]

Commercially produced cyanobacteria preparations sold under the name spirulina are widely consumed, due to their traditional use as a nutrient-rich foodstuff and subsequent marketing as a superfood. Despite their popularity, the microbial composition of ponds used to cultivate these bacteria is understudied. A total of 19 pond samples were obtained from small-scale spirulina farms and subjected to metagenome and/or virome sequencing, and the results were analysed. A remarkable level of prokaryotic and viral diversity was found to be present in the ponds, with Limnospira sp. and Arthrospira sp. sometimes being notably scarce. A detailed breakdown of prokaryotic and viral components of 15 samples is presented. Twenty putative Limnospira sp.-infecting bacteriophage contigs were identified, though no correlation between the performance of these cultures and the presence of phages was found. The high diversity of these samples prevented the identification of clear trends in sample performance over time, between ponds or when comparing successful and failed fermentations. [ABSTRACT FROM AUTHOR]

Harmful Algal Blooms (HABs) are outbreaks of aquatic toxic microalgae emerging as a global problem driven by nutrient enrichment, global climate change and invasive species. We uniquely describe a HAB of unprecedented duration, extent and magnitude during 2023 in Lough Neagh; the UK and Ireland’s largest freshwater lake, using an unparalleled combination of satellite imagery, nutrient analysis, 16S rRNA gene sequencing and cyanotoxin profiling. The causative agent Microcystis aeruginosa accounted for over a third of DNA in water samples though common bacterioplankton species also bloomed. Water phosphate levels were hypertrophic and drove local algal biomass. The HAB pervaded the entire ecosystem with algal mats accumulating around jetties, marinas and lock gates. Over 80 % of bacterial DNA isolated from algal mat samples consisted of species associated with wildfowl or livestock faeces and human-effluent wastewater including 13 potential pathogens that can cause serious human illness including: E. coli, Salmonella, Enterobacter and Clostridium among others. Ten microcystins, nodularin and two anabaenopeptin toxins were confirmed as present (with a further microcystin and four anabaenopeptins suspected), with MC-RR and -LR in high concentrations at some locations (1,137–18,493 μg/L) with MC-LR exceeding World Health Organisation (WHO) recreational exposure guidelines in all algal mats sampled. This is the first detection of anabaenopeptins in any waterbody on the island of Ireland. Notwithstanding the ecological impacts, this HAB represented an environmental and public health risk, curtailing recreational activities in-and-around the lake and damaging local businesses. Reducing agricultural runoff and discharge from human-effluent wastewater treatment to manage nutrient loading, and the public health risk, should be the top priority of stakeholders, especially government. Key recommendations include Nature-based Solutions that avoid conflict with the productivity and profitability of the farming sector enhancing sustainability. We hope this stimulates real-world action to resolve the problems besetting this internationally important ecosystem.

A unicellular cyanobacterium, strain VI4D9, was isolated from thermophilic microbial mats thriving in a hot spring of the Ahousaht territory of Vancouver Island, Canada, and characterized using optical and electron microscopy, genome sequencing and cultivation approaches. The cells were elongated rods (5.1 µm in length and 1.2 µm in width, on average). Their UV visible absorption spectra revealed that they contain chlorophyll a, phycocyanin and carotenoids. Transmission electron microscopy showed the presence of thylakoids concentrated on one side of the cells. The strain grew within a temperature range of 37–50°C, with an optimum growth at 45°C. Its genome had a size of 3 049 282 bp and a DNA G + C content of 51.8 mol%. The cells contained numerous intracellular spherical granules easily visible under scanning electron microscopy. Energy dispersive X-ray spectroscopy revealed that these granules were made of Ca-, Ba- and Sr-containing carbonates. A phylogenetic 16S rRNA gene tree robustly placed this strain as sister to several environmental sequences and the described species Gloeomargarita lithophora, also characterized by the possession of intracellular carbonate inclusions. We consider strain VI4D9 to represent a new Gloeomargarita species based on its marked phenotypic differences with G. lithophora, notably, its thermophilic nature and different thylakoid organization, therefore we propose the name Gloeomargarita ahousahtiae sp. nov. The type strain is VI4D9 (Culture Collection of Algae and Protozoa strain 1472/1; Laboratorio de Algas Continentales Mexico strain LAC 140). Gloeomargarita ahousahtiae is the second species described within the recently discovered order Gloeomargaritales. Gloeomargarita ahousahtiae is a new thermophilic cyanobacterium. Growth temperature and thylakoid morphology differentiate G. ahousahtiae and G. lithophora. All described Gloeomargaritales synthesize intracellular carbonate inclusions. [ABSTRACT FROM AUTHOR]

The blue-green algae are known as Anabaena flos-aquae, which is a nutrient-rich food supply. The 2nd and 4th larval instars of the cotton bollworm, Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) were tested in a lab using a crude extract of the cyanobacterial isolates of the Anabaena flos-aquae alga. The algal extract was administered to larvae via contact and feeding techniques. Depending on the larval instars and the applying technique, the algal extract's effects changed. Contact algal treatment was more successful than the feeding treatment. Also, the second larval instar was more vulnerable than the fourth. In terms of contact treatment, the LC50 value for the second larval instar was 0.0125 ml/l, while the fourth instar's 0.025 ml/l. In terms of feeding treatment, the LC50 value was 0.05 and 0.1 ml/l for the second and fourth instars, respectively. In contrast to controls, where adults emerged at a rate of 100% compared to 85%- 86% adults emerged as second instar and fourth instar in terms of feeding method, respectively. While adults emerged of second instar and fourth instar in terms of contact method was 81%-93%, respectively. The contact method's LC50 value for the second larval instar caused a highly significant increase in larval and pupal durations and a drop in adult emergence. Also, the contact method's LC50 value for the second larval instar caused the greatest percentage of pupation malformation 37%, and adult malformation (19%). Also, adults that emerged from the contact-treated 4th larval instar showed a significant decrease in egg hatchability to 82.4%. It was found that the proportion of pupation had significantly decreased. Additionally, adult longevity and adult emergence percentage were decreased for contact or feeding treatments on the fourth larval instar. [ABSTRACT FROM AUTHOR]

Cyanobacteria blooms represent a global problem with human health and economic and ecosystem nuisance effects. Until now, we have used arbitrary and sometimes confusing criteria to decide whether we are in the presence of a Cyanobacteria bloom. Through scientometric analysis of studies published between 1953 and 2022, I aimed to identify a threshold value that can be used to quantify Cyanobacteria blooms numerically. I considered several methodological approaches (field, field-experimental, and satellite data) and kinds of environments (coastal, marine, and continental ecosystems). The analysis revealed that 48% of the papers used "cyanobacteria bloom" or similar terms qualitatively without providing or employing a quantitative definition. These papers were focused on other topics related to the ecology of Cyanobacteria (78%), while some others (21%) defined blooms by using visual criteria (scum visualization or water discoloration). Of the other half (52%), a few were mathematical models or review papers (5%), while the rest (65%) defined blooms quantitatively. Of these, most reports (approximately 80%) were from eutrophic inland waters and reported mean values for blooms between 80 000 and 249 000 cells mL−1 or 41 and 69 µg L−1 of chlorophyll-a. Calculations were also carried out for oligotrophic to mesotrophic inland waters and marine-coastal waters, which had fewer reports available in the literature. This is a first attempt to identify a consensual definition based on values reported as blooms in nature, a threshold that can undoubtedly be useful in the future to make possible comparisons among several environments and temporal scales. [ABSTRACT FROM AUTHOR]

Commercially produced cyanobacteria preparations sold under the name spirulina are widely consumed, due to their traditional use as a nutrient-rich foodstuff and subsequent marketing as a superfood. Despite their popularity, the microbial composition of ponds used to cultivate these bacteria is understudied. A total of 19 pond samples were obtained from small-scale spirulina farms and subjected to metagenome and/or virome sequencing, and the results were analysed. A remarkable level of prokaryotic and viral diversity was found to be present in the ponds, with Limnospira sp. and Arthrospira sp. sometimes being notably scarce. A detailed breakdown of prokaryotic and viral components of 15 samples is presented. Twenty putative Limnospira sp.-infecting bacteriophage contigs were identified, though no correlation between the performance of these cultures and the presence of phages was found. The high diversity of these samples prevented the identification of clear trends in sample performance over time, between ponds or when comparing successful and failed fermentations.

A multifunctional weir was built on the Nakdong River. As a result, changes in the river environment occurred, such as an increase in river residence time. This causes changes in water quality, including green algae. The occurrence of green algae in the Nakdong River, which is used as a water source, also affects the purified water supply system. In particular, the mass spread of harmful algae is becoming a major problem as the frequency and intensity of occurrences increase. There are various causes of blue-green algae. We would like to examine the relationships between causal factors through a decision tree-based algorithm. Additionally, we would like to predict the occurrence of green algae based on the combination of these factors. For prediction, we studied categorical prediction based on the blue-green algae warning system used in Korea. RF, Catboost and XGBoost algorithms were used. Optimal hyperparameters were applied. We compared the prediction performance of each algorithm. In addition, the predictability of using sensor-based data was reviewed for a preemptive response to the occurrence of blue-green algae. By applying sensor-based data, the accuracy was over 80%. Prediction accuracy by category was also over 75%. It is believed that real-time prediction is possible through sensor-based factors. The optimal forecast period was analyzed to determine whether a preemptive response was possible and the possibility of improvement was examined through the segmentation of prediction categories. When there were three categories, 79% of predictions were possible by the 21st day. In seven categories, 75% prediction was possible up to 14 days. In this study, sensor-based categorical predictability was derived. In addition, real-time response and proactive response were determined. Such sensor-based algae prediction research is considered important for future blue-green algae management and river management. [ABSTRACT FROM AUTHOR]

In 2019, cyanobacterial samples were collected from thermal sites in Yellowstone National Park. In this paper, we discuss the considerable richness of representatives of simple filamentous cyanobacteria. Using a polyphasic approach, one new genus, Copelandiella, with two species (C. yellowstonensis and C. thermalis) and eight additional new species Albertania prattii, K. anagnostidisii, Kovacikia brockii, Leptolyngbya tildenae, L. vaporiphila, Nodosilinea calida, N. igneolacustris, and Oculatella castenholzii were described. At the same time, by analyzing our new molecular data, we concluded that other genera of trichal cyanobacteria can be merged with existing genera: species within the genus Plectolyngbya are herein transferred to Leptolyngbya, and if some nomenclatural issues are resolved, species within the genus Leptothermofonsia will be subsequently transferred to the genus Kovacikia, an earlier synonym. [ABSTRACT FROM AUTHOR]

Climate and anthropogenic change, particularly agricultural runoff, increase blue-green algae/cyanobacteria blooms. This article researches cyanobacteria alert-level identification, management, and risk communication in Lake Hume, Australia. Two methods, document and content analysis, evidence contamination events and risk communication, reflect water governance and data management limitations. Results found that Lake Hume had amber or red alerts for only one week, December 2021–December 2022. This failed to prevent government tourism promotion of recreational usage, contravening water authority red alert advice. Lake-use restrictions lacked compliance enforcement. Events during amber alerts lacked risk communication to vulnerable populations (children). Lake Hume's governance by the Murray–Darling Basin Authority restricted risk communication to one authority that reproduced generic advice in minimal outlets/time points. Geophysical signage failed to address diversity needs (language, literacy, age, and disabilities). No risk communication was found for residents with diseases exacerbated by aerosolization. Despite WHO promoting cyanotoxin investigation, Australian research is absent in international literature. Further, Lake Hume cyanobacteria produce potentially carcinogenic microcystein. This coexists with census data revealing cancer rates higher than the national average in a waterside town. The results demonstrate the need to incorporate robust public health risk assessments, communication, and management into water management and advocate international legislation changes based on evidence-based research to reduce blooms and prevent agricultural runoff. [ABSTRACT FROM AUTHOR]

There is an urgent demand for biostimulant amendments that can sustainably alleviate osmotic stress. However, limited information is available about the integrated application of vermicompost and a cyanobacteria extract on cotton plants. In 2020 and 2021, two field experiments were carried out in which twelve combinations of three irrigation intervals were employed every 14 days (Irrig.14), 21 days (Irrig.21), and 28 days (Irrig.28) along with four amendment treatments (a control, vermicompost, cyanobacteria extract, and combination of vermicompost + cyanobacteria extract) in salt-affected soil. The integrative use of vermicompost and a cyanobacteria extract resulted in an observed improvement in the physicochemical attributes; non-enzymatic antioxidants (free amino acids, proline, total soluble sugars, and phenolics); and antioxidant enzyme activities of catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) and a decrease in the levels of oxidative damage indicators (H2O2 and MDA). Significant augmentation in the content of chlorophyll a and b, carotenoid concentration, relative water content, stomatal conductance, and K+ was also observed. In conjunction with these findings, noticeable decreases in the content of Na+ and hydrogen peroxide (H2O2) and the degree of lipid peroxidation (MDA) proved the efficacy of this technique. Consequently, the highest cotton yield and productivity as well as fiber quality were achieved when vermicompost and a cyanobacteria extract were used together under increasing irrigation intervals in salt-affected soil. In conclusion, the integrated application of vermicompost and a cyanobacteria extract can be helpful for obtaining higher cotton productivity and fiber quality compared with the studied control and the individual applications of the vermicompost or the cyanobacteria extract under increasing irrigation intervals within salt-affected soil. Additionally, it can also help alleviate the harmful impact of these abiotic stresses. [ABSTRACT FROM AUTHOR]