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Susanna A. Wood - One of the best experts on this subject based on the ideXlab platform.
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extracts from benthic anatoxin producing Phormidium are toxic to 3 macroinvertebrate taxa at environmentally relevant concentrations
Environmental Toxicology and Chemistry, 2018Co-Authors: Brian S Anderson, Jennifer P Voorhees, Bryn M Phillips, Rich Fadness, Rosalina Stancheva, Jeanette Nichols, Daniel Orr, Susanna A. WoodAbstract:Toxin-producing cyanobacteria are increasing in rivers and streams globally, leading to growing concerns over their potential impacts on aquatic ecosystems. The present study was designed to culture field-collected Phormidium in the laboratory, identify individual species, conduct chemical analyses to identify cyanotoxins, and conduct toxicity tests to investigate the potential for this genera to impact stream health. Freshwater toxicity tests were conducted with standard US Environmental Protection Agency invertebrate test protocols with culture water used to grow 3 Phormidium strains isolated from the Russian River (CA, USA). Enzyme linked immunosorbent assays were used to measure total anatoxin concentrations. Culture waters from the 3 Phormidium strains were highly toxic to Ceriodaphnia dubia, Hyalella azteca, and Chironomus dilutus. The C. dubia 7-d survival median lethal concentrations were 0.71, 0.49, and 0.56 μg/L anatoxin for Phormidum strains 1, 2, and 3, respectively. The 7-d reproduction inhibitory concentrations, 25% were 0.55, 0.32, and 0.30 μg/L anatoxin for strains 1, 2, and 3, respectively. Chironomus dilutus survival was reduced at concentrations <2 μg/L anatoxin by all 3 strains, and the H. azteca 96-h lethal concentrations, 25% were 2.82, 1.26, and 5.30 μg/L for strains 1, 2, and 3, respectively. Additional liquid chromatography-mass spectrometry analyses demonstrated that the likely anatoxin variant in these cultures was dihydro-anatoxin-a. The results suggest that anatoxins produced by Phormidium have the potential to impact stream macroinvertebrates. Environ Toxicol Chem 2018;37:2851-2859. © 2018 SETAC.
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Multiple processes acting from local to large geographical scales shape bacterial communities associated with Phormidium (cyanobacteria) biofilms in French and New Zealand rivers.
Scientific reports, 2018Co-Authors: Isidora Echenique-subiabre, Susanna A. Wood, Mark W. Heath, Catherine Quiblier, Anouk Zancarini, Jeanfrancois HumbertAbstract:River biofilms dominated by Phormidium (cyanobacteria) are receiving increased attention worldwide because of a recent expansion in their distribution and their ability to produce neurotoxins leading to animal mortalities. Limited data are available on the composition and structure of bacterial communities (BCs) associated with Phormidium biofilms despite the important role they potentially play in biofilm functioning. By using a high-throughput sequencing approach, we compared the BCs associated with Phormidium biofilms in several sampling sites of the Tarn River (France) and in eight New Zealand rivers. The structure of the BCs from both countries displayed spatial and temporal variations but were well conserved at the order level and 28% of the OTUs containing 90% of the reads were shared by these BCs. This suggests that micro-environmental conditions occurring within thick Phormidium biofilms strongly shape the associated BCs. A strong and significant distance-decay relationship (rp = 0.7; P = 0.001) was found in BCs from New Zealand rivers but the Bray-Curtis dissimilarities between French and New Zealand BCs are in the same order of magnitude of those found between New Zealand BCs. All these findings suggest that local environmental conditions seem to have more impact on BCs than dispersal capacities of bacteria.
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Extracts from benthic anatoxin-producing Phormidium are toxic to 3 macroinvertebrate taxa at environmentally relevant concentrations.
Environmental toxicology and chemistry, 2018Co-Authors: Brian S Anderson, Jennifer P Voorhees, Bryn M Phillips, Rich Fadness, Rosalina Stancheva, Jeanette Nichols, Daniel Orr, Susanna A. WoodAbstract:Toxin-producing cyanobacteria are increasing in rivers and streams globally, leading to growing concerns over their potential impacts on aquatic ecosystems. The present study was designed to culture field-collected Phormidium in the laboratory, identify individual species, conduct chemical analyses to identify cyanotoxins, and conduct toxicity tests to investigate the potential for this genera to impact stream health. Freshwater toxicity tests were conducted with standard US Environmental Protection Agency invertebrate test protocols with culture water used to grow 3 Phormidium strains isolated from the Russian River (CA, USA). Enzyme linked immunosorbent assays were used to measure total anatoxin concentrations. Culture waters from the 3 Phormidium strains were highly toxic to Ceriodaphnia dubia, Hyalella azteca, and Chironomus dilutus. The C. dubia 7-d survival median lethal concentrations were 0.71, 0.49, and 0.56 μg/L anatoxin for Phormidum strains 1, 2, and 3, respectively. The 7-d reproduction inhibitory concentrations, 25% were 0.55, 0.32, and 0.30 μg/L anatoxin for strains 1, 2, and 3, respectively. Chironomus dilutus survival was reduced at concentrations
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spatiotemporal dynamics of Phormidium cover and anatoxin concentrations in eight new zealand rivers with contrasting nutrient and flow regimes
Science of The Total Environment, 2018Co-Authors: Tara G Mcallister, Susanna A. Wood, Javier Atalah, Ian HawesAbstract:Abstract Toxic benthic cyanobacterial proliferations, particularly of the genus Phormidium, are a major concern in many countries due to their increasing extent and severity. The aim of this study was to improve the current understanding of the dominant physicochemical variables associated with high Phormidium cover and toxin concentrations. Phormidium cover and anatoxin concentrations were assessed weekly for 30 weeks in eight predominately cobble-bed rivers in the South Island of New Zealand. Phormidium cover was highly variable both spatially (among and within sites) and temporally. Generalized additive mixed models (GAMMs) identified site, month of the year, conductivity and nutrient concentrations over the accrual period as significant variables associated with Phormidium cover. Cover was greatest under low to intermediate accrual dissolved inorganic nitrogen (DIN) and dissolved reactive phosphorus (DRP) concentrations. Accrual nutrients had a strong, negative effect on cover at concentrations > 0.2 mg L− 1 DIN and 0.014 mg L− 1 DRP. The effect of flow was generally consistent across rivers, with cover accruing with time since the last flushing flow. Total anatoxins were detected at all eight study sites, at concentrations ranging from 0.008 to 662.5 mg kg− 1 dried weight. GAMMs predicted higher total anatoxin concentrations between November and February and during periods of accrual DRP
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spatiotemporal dynamics of Phormidium cover and anatoxin concentrations in eight new zealand rivers with contrasting nutrient and flow regimes
Science of The Total Environment, 2018Co-Authors: Tara G Mcallister, Susanna A. Wood, Javier Atalah, Ian HawesAbstract:Toxic benthic cyanobacterial proliferations, particularly of the genus Phormidium, are a major concern in many countries due to their increasing extent and severity. The aim of this study was to improve the current understanding of the dominant physicochemical variables associated with high Phormidium cover and toxin concentrations. Phormidium cover and anatoxin concentrations were assessed weekly for 30weeks in eight predominately cobble-bed rivers in the South Island of New Zealand. Phormidium cover was highly variable both spatially (among and within sites) and temporally. Generalized additive mixed models (GAMMs) identified site, month of the year, conductivity and nutrient concentrations over the accrual period as significant variables associated with Phormidium cover. Cover was greatest under low to intermediate accrual dissolved inorganic nitrogen (DIN) and dissolved reactive phosphorus (DRP) concentrations. Accrual nutrients had a strong, negative effect on cover at concentrations>0.2mgL-1 DIN and 0.014mgL-1 DRP. The effect of flow was generally consistent across rivers, with cover accruing with time since the last flushing flow. Total anatoxins were detected at all eight study sites, at concentrations ranging from 0.008 to 662.5mgkg-1 dried weight. GAMMs predicted higher total anatoxin concentrations between November and February and during periods of accrual DRP<0.02mgL-1. This study suggests that multiple physicochemical variables may influence Phormidium proliferations and also evidenced large site-to-site variability. This result highlights a challenge from a management perspective, as it suggests that mitigation options are likely to be site-specific.
Ian Hawes - One of the best experts on this subject based on the ideXlab platform.
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spatiotemporal dynamics of Phormidium cover and anatoxin concentrations in eight new zealand rivers with contrasting nutrient and flow regimes
Science of The Total Environment, 2018Co-Authors: Tara G Mcallister, Susanna A. Wood, Javier Atalah, Ian HawesAbstract:Abstract Toxic benthic cyanobacterial proliferations, particularly of the genus Phormidium, are a major concern in many countries due to their increasing extent and severity. The aim of this study was to improve the current understanding of the dominant physicochemical variables associated with high Phormidium cover and toxin concentrations. Phormidium cover and anatoxin concentrations were assessed weekly for 30 weeks in eight predominately cobble-bed rivers in the South Island of New Zealand. Phormidium cover was highly variable both spatially (among and within sites) and temporally. Generalized additive mixed models (GAMMs) identified site, month of the year, conductivity and nutrient concentrations over the accrual period as significant variables associated with Phormidium cover. Cover was greatest under low to intermediate accrual dissolved inorganic nitrogen (DIN) and dissolved reactive phosphorus (DRP) concentrations. Accrual nutrients had a strong, negative effect on cover at concentrations > 0.2 mg L− 1 DIN and 0.014 mg L− 1 DRP. The effect of flow was generally consistent across rivers, with cover accruing with time since the last flushing flow. Total anatoxins were detected at all eight study sites, at concentrations ranging from 0.008 to 662.5 mg kg− 1 dried weight. GAMMs predicted higher total anatoxin concentrations between November and February and during periods of accrual DRP
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spatiotemporal dynamics of Phormidium cover and anatoxin concentrations in eight new zealand rivers with contrasting nutrient and flow regimes
Science of The Total Environment, 2018Co-Authors: Tara G Mcallister, Susanna A. Wood, Javier Atalah, Ian HawesAbstract:Toxic benthic cyanobacterial proliferations, particularly of the genus Phormidium, are a major concern in many countries due to their increasing extent and severity. The aim of this study was to improve the current understanding of the dominant physicochemical variables associated with high Phormidium cover and toxin concentrations. Phormidium cover and anatoxin concentrations were assessed weekly for 30weeks in eight predominately cobble-bed rivers in the South Island of New Zealand. Phormidium cover was highly variable both spatially (among and within sites) and temporally. Generalized additive mixed models (GAMMs) identified site, month of the year, conductivity and nutrient concentrations over the accrual period as significant variables associated with Phormidium cover. Cover was greatest under low to intermediate accrual dissolved inorganic nitrogen (DIN) and dissolved reactive phosphorus (DRP) concentrations. Accrual nutrients had a strong, negative effect on cover at concentrations>0.2mgL-1 DIN and 0.014mgL-1 DRP. The effect of flow was generally consistent across rivers, with cover accruing with time since the last flushing flow. Total anatoxins were detected at all eight study sites, at concentrations ranging from 0.008 to 662.5mgkg-1 dried weight. GAMMs predicted higher total anatoxin concentrations between November and February and during periods of accrual DRP<0.02mgL-1. This study suggests that multiple physicochemical variables may influence Phormidium proliferations and also evidenced large site-to-site variability. This result highlights a challenge from a management perspective, as it suggests that mitigation options are likely to be site-specific.
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The effects of velocity and nitrate on Phormidium accrual cycles: a stream mesocosm experiment
Freshwater Science, 2018Co-Authors: Tara G Mcallister, Susanna A. Wood, Michelle J. Greenwood, Felix Broghammer, Ian HawesAbstract:AbstractProliferations of benthic cyanobacteria in the genus Phormidium are a global concern because of their increasing prevalence and ability to produce harmful toxins. Most studies have been obs...
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effect of river flow temperature and water chemistry on proliferations of the benthic anatoxin producing cyanobacterium Phormidium
Freshwater Science, 2017Co-Authors: Susanna A. Wood, Roger G. Young, Javier Atalah, Annika Wagenhoff, Logan Brown, Kati Doehring, Ian HawesAbstract:AbstractProliferations of the benthic anatoxin-producing cyanobacterium Phormidium are increasing in prevalence in cobble-bed rivers worldwide. This proliferation is of particular concern when rivers are used as sources of drinking water or for recreation. Little is known about the physicochemical variables promoting proliferations, and our existing knowledge is based on data from only a few rivers. We assessed Phormidium cover, physicochemical variables, and anatoxin concentrations at 10 sites in 7 New Zealand rivers every week for 2 y. Generalized additive mixed models (GAMMs) identified dissolved inorganic N (DIN) over the accrual period 15°C, and conductivity as having positive and statistically significant effects on % Phormidium cover. Flow intensity, expressed relative to the long-term median, had a positive effect up to 0.4× the median flow and a negative effect when >0.5× the median flow. Quantile regression models showed ma...
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The rise of toxic benthic Phormidium proliferations: A review of their taxonomy, distribution, toxin content and factors regulating prevalence and increased severity
Harmful algae, 2016Co-Authors: Tara G Mcallister, Susanna A. Wood, Ian HawesAbstract:There has been a marked increase in the distribution, intensity and frequency of proliferations of some species of the benthic mat-forming, toxin-producing genus Phormidium in rivers globally over the last decade. This review summarises current knowledge on their taxonomy, distribution, toxin content, environmental drivers of proliferations, and monitoring and management strategies in New Zealand. Although toxic Phormidium proliferation occurs in rivers worldwide little is known about these factors in most countries. Proliferations, defined as >20% cover of a riverbed, have been identified in 103 rivers across New Zealand. Morphological and molecular data indicate the main species responsible is Phormidium autumnale. In New Zealand Phormidium produces anatoxins (anatoxin-a, homoanatoxin-a, dihydroanatoxin-a, and dihydrohomoanatoxin-a) and these were detected in 67% of 771 samples from 40 rivers. The highest concentration measured was 712mgkg-1 dried weight (Oreti River, Southland), with considerable spatial and temporal variability in anatoxin concentrations between and within rivers. A synthesis of field based studies suggests that Phormidium proliferations are most likely when there is some enrichment of dissolved inorganic nitrogen but when water-column dissolved reactive phosphorus is less than 0.01mgL-1. Once established Phormidium-dominated mats trap sediment and internal mat biogeochemistry can mobilise sediment-bound phosphorus, which is then available for growth. Removal of Phormidium-dominated mats is primarily due to shear stress and substrate disturbance, although there is also evidence for autogenic detachment. A combination of factors including; changes to riparian margins, increased nitrate and fine sediment loads, and alterations in flow regimes are likely to have contributed to the rise in Phormidium proliferations.
Ken G. Ryan - One of the best experts on this subject based on the ideXlab platform.
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The role of nitrogen and phosphorus in regulating Phormidium sp. (cyanobacteria) growth and anatoxin production.
FEMS microbiology ecology, 2016Co-Authors: Mark W. Heath, Roger G. Young, Susie A. Wood, Ken G. RyanAbstract:Benthic proliferations of the cyanobacteria Phormidium can cover many kilometres of riverbed. Phormidium can produce neurotoxic anatoxins and ingestion of benthic mats has resulted in numerous animal poisonings in the last decade. Despite this, there is a poor understanding of the environmental factors regulating growth and anatoxin production. In this study, the effects of nitrogen and phosphorus on the growth of two Phormidium strains (anatoxin-producing and non-anatoxin-producing) were examined in batch monocultures. Cell concentrations were significantly reduced under reduced nitrogen (ca. 407 fg cell−1) in the reduced phosphorus treatments, possibly suggesting that it is produced as a stress response to growth limiting conditions. In all treatments there was a 4–5-fold increase in anatoxin quota in the lag growth phase, possibly indicating it may provide a physiological benefit during initial substrate colonization.
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Development of Habitat Suitability Criteria and In-Stream Habitat Assessment for the Benthic Cyanobacteria Phormidium
River Research and Applications, 2013Co-Authors: Mark W. Heath, Roger G. Young, Susanna A. Wood, K. A. Brasell, Ken G. RyanAbstract:Global demand for freshwater has led to unprecedented levels of water abstraction from riverine systems. This has resulted in large alterations in natural river flows. The deleterious impacts of reduced flows on fish and macroinvertebrate abundances have been thoroughly investigated; in contrast, there is a limited understanding of the potential for changes in the abundance of nuisance benthic algal/cyanobacterial blooms. In New Zealand, Phormidium sp. blooms are common in numerous rivers during summer low flows. In this study, an in-stream habitat assessment is used to examine the relationship between Phormidium habitat availability and reducing flows. Over 650 observations of Phormidium mats, from seven sites (Hutt River, lower North Island, New Zealand), were used to construct habitat suitability curves for depth, velocity and substrate. Preference curves were fitted using both the ‘forage ratio’ and ‘quantile regression’ methods. Phormidium growth, observed at all seven sites, increased significantly from upstream (uppermost site, 5.2% mat cover) to downstream (63.5%). The habitat suitability curves revealed Phormidium had a large tolerance to velocity, depth and substrate type. Consequently, decreases in flow had only negligible effects on available Phormidium habitat. During periods of stable flow, Phormidium abundance positively correlated with increased nitrogen concentrations, potentially explaining the large variation in Phormidium cover from upstream to downstream. Quantile regression generated habitat suitability criteria were a more accurate predictor of available Phormidium habitat than the forage ratio criteria. Copyright © 2013 John Wiley & Sons, Ltd.
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Within-Mat Variability in Anatoxin-a and Homoanatoxin-a Production among Benthic Phormidium (Cyanobacteria) Strains
Toxins, 2012Co-Authors: Susanna A. Wood, Roger G. Young, Mark W. Heath, Francine M. J. Smith, Thomas Palfroy, Sally Gaw, Ken G. RyanAbstract:Benthic Phormidium mats can contain high concentrations of the neurotoxins anatoxin-a and homoanatoxin-a. However, little is known about the co-occurrence of anatoxin-producing and non-anatoxin-producing strains within mats. There is also no data on variation in anatoxin content among toxic genotypes isolated from the same mat. In this study, 30 Phormidium strains were isolated from 1 cm2 sections of Phormidium-dominated mats collected from three different sites. Strains were grown to stationary phase and their anatoxin-a, homoanatoxin-a, dihydroanatoxin-a and dihydrohomoanatoxin-a concentrations determined using liquid chromatography-mass spectrometry. Each strain was characterized using morphological and molecular (16S rRNA gene sequences) techniques. Eighteen strains produced anatoxin-a, dihydroanatoxin-a or homoanatoxin-a. Strains isolated from each mat either all produced toxins, or were a mixture of anatoxin and non-anatoxin-producing genotypes. Based on morphology these genotypes could not be separated. The 16S rRNA gene sequence comparisons showed a difference of at least 17 nucleotides among anatoxin and non-anatoxin-producing strains and these formed two separate sub-clades during phylogenetic analysis. The total anatoxin concentration among toxic strains varied from 2.21 to 211.88 mg kg−1 (freeze dried weight), representing a 100 fold variation in toxin content. These data indicate that both the relative abundance of anatoxin and non-anatoxin-producing genotypes, and variations in anatoxin producing capability, can influence the overall toxin concentration of benthic Phormidium mat samples.
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spatial and temporal variability in Phormidium mats and associated anatoxin a and homoanatoxin a in two new zealand rivers
Aquatic Microbial Ecology, 2011Co-Authors: Mark W. Heath, Susanna A. Wood, Ken G. RyanAbstract:Toxic benthic cyanobacterial proliferations in freshwater are becoming increasingly prevalent, and associated animal poisonings are being reported with greater regularity. Despite this, few studies have investigated spatial and temporal variations in freshwater mat-forming Cyanobac- teria and their associated toxin production. Some sections of the Hutt and Wainuiomata rivers (lower North Island, New Zealand) contain extensive Phormidium sp. proliferations that sometimes produce anatoxin-a (ATX) and homoanatoxin-a (HTX). The percentage coverage of Phormidium sp., ATX and/or HTX concentrations and a suite of physicochemical parameters were monitored at 8 sites for 12 mo. The percentage coverage of Phormidium mats was greater in the summer months and these correlated with warmer water temperatures and stable river flows. Flows in excess of 3 times the mean resulted in the removal of Phormidium mats. There was no correlation between the presence/absence of Phormidium mats and water-soluble nutrients. The presence and concentration of ATX and/or HTX and their degradation products, dihydroanatoxin-a and dihydrohomoanatoxin-a, was highly variable across all sites and over time. Anatoxin-a and HTX occurrence was restricted to periods of warm water temperatures (above 13.4°C) and below average river flows.
Gonul Donmez - One of the best experts on this subject based on the ideXlab platform.
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microbial oil production from thermophile cyanobacteria for biodiesel production
Applied Energy, 2011Co-Authors: Sevgi Ertugrul Karatay, Gonul DonmezAbstract:Compared to lipid extraction from algae, little work has been performed for cyanobacteria. In this article it is aimed to show high lipid accumulation potential of Synechococcus sp., Cyanobacterium aponinum and Phormidium sp. cells in BG-11 medium. Four different pH values (6–9) and NaNO3 (0.25, 0.5, 1.0, 1.5g/L) concentrations were examined at different incubation days to discover the highest lipid accumulation. The maximum lipid content could be achieved in the medium containing 0.25g/L NaNO3 at pH 7 for Synechococcus sp., pH 8 for C. aponinum and pH 9 for Phormidium sp. after 15days. The maximum lipid contents and C16 and C18 methyl ester yields were measured as 42.8% and 46.9% for Synechococcus sp., 45.0% and 67.7% for C. aponinum, 38.2% and 90.6% for Phormidium sp. The saturated compounds were 74.5%, 77.9%, 84.7% for Synechococcus sp., C. aponinum and Phormidium sp., respectively. These crude lipids could be promising feedstock for biodiesel production.
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stimulation of reactive dye removal by cyanobacteria in media containing triacontanol hormone
Journal of Hazardous Materials, 2009Co-Authors: Pinar Karacakaya, Nur Kocberber Kilic, Ergin Duygu, Gonul DonmezAbstract:In this study, Reactive Red, Remazol Blue, and Reactive Black B removal capacities of Synechocystis sp. and Phormidium sp. were investigated. The microorganisms were cultivated in 100 ml BG 11 medium and incubated at 30 ◦ C under continuous illumination (12.5 w m −2 (2400 lx)) for 20 days in plant growth chamber. Trials were carried out at pH 9.5 for Reactive Red, pH 8.5 for Remazol Blue and Reactive Black B removal in media without and with triacontanol (TRIA). Removal capacities of Synechocystis sp. and Phormidium sp. were found higher in media containing TRIA. So that, Synechocystis sp. and Phormidium sp. removed Reactive Red with 25.7% and 35.4%, Remazol Blue with 37.5% and 25.5%, and Reactive Black B with 29.2% and 28.3% yield at 25 mg l −1 dye concentrations, respectively. There is no report investigating dye removal by Synechocystis sp. and removal of pollutants in media including TRIA hormone. Our data indicated the cyanobacteria tested in this study were suitable for effective treatment processes of such wastewaters including reactive dyes, and their removal capacity could be increased by TRIA, through stimulation of the biomass production.
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Stimulation of reactive dye removal by cyanobacteria in media containing triacontanol hormone.
Journal of hazardous materials, 2009Co-Authors: Pinar Karacakaya, Nur Kocberber Kilic, Ergin Duygu, Gonul DonmezAbstract:In this study, Reactive Red, Remazol Blue, and Reactive Black B removal capacities of Synechocystis sp. and Phormidium sp. were investigated. The microorganisms were cultivated in 100ml BG 11 medium and incubated at 30 degrees C under continuous illumination (12.5 wm(-2) (2400 lx)) for 20 days in plant growth chamber. Trials were carried out at pH 9.5 for Reactive Red, pH 8.5 for Remazol Blue and Reactive Black B removal in media without and with triacontanol (TRIA). Removal capacities of Synechocystis sp. and Phormidium sp. were found higher in media containing TRIA. So that, Synechocystis sp. and Phormidium sp. removed Reactive Red with 25.7% and 35.4%, Remazol Blue with 37.5% and 25.5%, and Reactive Black B with 29.2% and 28.3% yield at 25 mg l(-1) dye concentrations, respectively. There is no report investigating dye removal by Synechocystis sp. and removal of pollutants in media including TRIA hormone. Our data indicated the cyanobacteria tested in this study were suitable for effective treatment processes of such wastewaters including reactive dyes, and their removal capacity could be increased by TRIA, through stimulation of the biomass production.
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Treatment of dye-rich wastewater by an immobilized thermophilic cyanobacterial strain: Phormidium sp.
Ecological Engineering, 2008Co-Authors: Sevgi Ertuğrul, Melike Bakir, Gonul DonmezAbstract:Abstract The removal of Remazol Blue and Reactive Black B by the immobilized thermophilic cyanobacterial strain Phormidium sp. was investigated under thermophilic conditions in a batch system, in order to determine the optimal conditions required for the highest dye removal. In the experiments, performed at pH 8.5, with different initial dye concentrations between 9.1 mg l −1 and 82.1 mg l −1 and at 45 °C, calcium alginate immobilized Phormidium sp. showed high dye decolorization, with maximum uptake yields ranging from 50% to 88% at all dye concentrations tested. When the effects of high dye concentrations on dye removal were investigated, the highest uptake yield in the beads was 50.3% for 82.1 mg l −1 Remazol Blue and 60.0% for 79.5 mg l −1 Reactive Black B. The highest color removal was detected at 45 °C and 50 °C incubation temperatures for all dye concentrations. As the temperature decreased, the removal yield of immobilized Phormidium sp. also decreased. At about 75 mg l −1 initial dye concentrations, the highest specific dye uptake measured was 41.29–41.17 mg g −1 for Remazol Blue and 47.69–43.82 mg g −1 for Reactive Black B at 45 °C and 50 °C incubation temperatures, respectively, after 8 days incubation.
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Bioaccumulation of reactive dyes by thermophilic cyanobacteria
Process Biochemistry, 2006Co-Authors: Sevgil Sadettin, Gonul DonmezAbstract:Abstract Thermophilic cyanobacterial strains that could grow in the BG 11 media was isolated from hot springs and their reactive dye bioaccumulation was studied under thermophilic conditions in a batch system, in order to determine the optimal conditions required for the highest dye accumulation. In the experiments performed with newly isolated Synechococcus sp. and Phormidium sp., the optimum pH value of each microorganisms at about 25 mg l −1 initial reactive dye concentration was determined as 8.5 for Remazol Blue and Reactive Black B dyes and 9.5 for Reactive Red RB dye. At the optimum pH value of each dye, dye bioaccumulation by thermophilic cyanobacteria was investigated between 10 mg l −1 and 78 mg l −1 initial dye concentrations at 45 °C. At the end of the experiments, Phormidium sp. was shown high dye bioaccumulation than the Synechococcus sp., with maximum uptake yields ranging from 13% to 97% at all tested dye concentrations. In the experiments with Synechococcus sp., the maximum uptake yields were ranged from 8% to 66% for all dye concentrations. When the effect of temperatures on dye bioaccumulation were investigated, the highest uptake yields at high dye concentrations for Synechococcus sp. was measured as 23.0% for 78.3 mg l −1 Reactive Red RB, 39.9% for 72.4 mg l −1 Remazol Blue and 13.7% for 62.0 mg l −1 Reactive Black B at 40 °C temperatures. At the same temperature, the uptake yield of Phormidium sp. varied between 38.5% and 40.7% at 75 mg l −1 initial dye concentration. When the high temperature (50 °C) was used, Phormidium sp. was showed to have high dry weight and bioaccumulation yield than the Synechococcus sp., which can be considered as satisfactory in terms of dye removal from subject wastewater effluents under thermophilic conditions.
Mark W. Heath - One of the best experts on this subject based on the ideXlab platform.
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Multiple processes acting from local to large geographical scales shape bacterial communities associated with Phormidium (cyanobacteria) biofilms in French and New Zealand rivers.
Scientific reports, 2018Co-Authors: Isidora Echenique-subiabre, Susanna A. Wood, Mark W. Heath, Catherine Quiblier, Anouk Zancarini, Jeanfrancois HumbertAbstract:River biofilms dominated by Phormidium (cyanobacteria) are receiving increased attention worldwide because of a recent expansion in their distribution and their ability to produce neurotoxins leading to animal mortalities. Limited data are available on the composition and structure of bacterial communities (BCs) associated with Phormidium biofilms despite the important role they potentially play in biofilm functioning. By using a high-throughput sequencing approach, we compared the BCs associated with Phormidium biofilms in several sampling sites of the Tarn River (France) and in eight New Zealand rivers. The structure of the BCs from both countries displayed spatial and temporal variations but were well conserved at the order level and 28% of the OTUs containing 90% of the reads were shared by these BCs. This suggests that micro-environmental conditions occurring within thick Phormidium biofilms strongly shape the associated BCs. A strong and significant distance-decay relationship (rp = 0.7; P = 0.001) was found in BCs from New Zealand rivers but the Bray-Curtis dissimilarities between French and New Zealand BCs are in the same order of magnitude of those found between New Zealand BCs. All these findings suggest that local environmental conditions seem to have more impact on BCs than dispersal capacities of bacteria.
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The role of nitrogen and phosphorus in regulating Phormidium sp. (cyanobacteria) growth and anatoxin production.
FEMS microbiology ecology, 2016Co-Authors: Mark W. Heath, Roger G. Young, Susie A. Wood, Ken G. RyanAbstract:Benthic proliferations of the cyanobacteria Phormidium can cover many kilometres of riverbed. Phormidium can produce neurotoxic anatoxins and ingestion of benthic mats has resulted in numerous animal poisonings in the last decade. Despite this, there is a poor understanding of the environmental factors regulating growth and anatoxin production. In this study, the effects of nitrogen and phosphorus on the growth of two Phormidium strains (anatoxin-producing and non-anatoxin-producing) were examined in batch monocultures. Cell concentrations were significantly reduced under reduced nitrogen (ca. 407 fg cell−1) in the reduced phosphorus treatments, possibly suggesting that it is produced as a stress response to growth limiting conditions. In all treatments there was a 4–5-fold increase in anatoxin quota in the lag growth phase, possibly indicating it may provide a physiological benefit during initial substrate colonization.
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Development of Habitat Suitability Criteria and In-Stream Habitat Assessment for the Benthic Cyanobacteria Phormidium
River Research and Applications, 2013Co-Authors: Mark W. Heath, Roger G. Young, Susanna A. Wood, K. A. Brasell, Ken G. RyanAbstract:Global demand for freshwater has led to unprecedented levels of water abstraction from riverine systems. This has resulted in large alterations in natural river flows. The deleterious impacts of reduced flows on fish and macroinvertebrate abundances have been thoroughly investigated; in contrast, there is a limited understanding of the potential for changes in the abundance of nuisance benthic algal/cyanobacterial blooms. In New Zealand, Phormidium sp. blooms are common in numerous rivers during summer low flows. In this study, an in-stream habitat assessment is used to examine the relationship between Phormidium habitat availability and reducing flows. Over 650 observations of Phormidium mats, from seven sites (Hutt River, lower North Island, New Zealand), were used to construct habitat suitability curves for depth, velocity and substrate. Preference curves were fitted using both the ‘forage ratio’ and ‘quantile regression’ methods. Phormidium growth, observed at all seven sites, increased significantly from upstream (uppermost site, 5.2% mat cover) to downstream (63.5%). The habitat suitability curves revealed Phormidium had a large tolerance to velocity, depth and substrate type. Consequently, decreases in flow had only negligible effects on available Phormidium habitat. During periods of stable flow, Phormidium abundance positively correlated with increased nitrogen concentrations, potentially explaining the large variation in Phormidium cover from upstream to downstream. Quantile regression generated habitat suitability criteria were a more accurate predictor of available Phormidium habitat than the forage ratio criteria. Copyright © 2013 John Wiley & Sons, Ltd.
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Within-Mat Variability in Anatoxin-a and Homoanatoxin-a Production among Benthic Phormidium (Cyanobacteria) Strains
Toxins, 2012Co-Authors: Susanna A. Wood, Roger G. Young, Mark W. Heath, Francine M. J. Smith, Thomas Palfroy, Sally Gaw, Ken G. RyanAbstract:Benthic Phormidium mats can contain high concentrations of the neurotoxins anatoxin-a and homoanatoxin-a. However, little is known about the co-occurrence of anatoxin-producing and non-anatoxin-producing strains within mats. There is also no data on variation in anatoxin content among toxic genotypes isolated from the same mat. In this study, 30 Phormidium strains were isolated from 1 cm2 sections of Phormidium-dominated mats collected from three different sites. Strains were grown to stationary phase and their anatoxin-a, homoanatoxin-a, dihydroanatoxin-a and dihydrohomoanatoxin-a concentrations determined using liquid chromatography-mass spectrometry. Each strain was characterized using morphological and molecular (16S rRNA gene sequences) techniques. Eighteen strains produced anatoxin-a, dihydroanatoxin-a or homoanatoxin-a. Strains isolated from each mat either all produced toxins, or were a mixture of anatoxin and non-anatoxin-producing genotypes. Based on morphology these genotypes could not be separated. The 16S rRNA gene sequence comparisons showed a difference of at least 17 nucleotides among anatoxin and non-anatoxin-producing strains and these formed two separate sub-clades during phylogenetic analysis. The total anatoxin concentration among toxic strains varied from 2.21 to 211.88 mg kg−1 (freeze dried weight), representing a 100 fold variation in toxin content. These data indicate that both the relative abundance of anatoxin and non-anatoxin-producing genotypes, and variations in anatoxin producing capability, can influence the overall toxin concentration of benthic Phormidium mat samples.
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spatial and temporal variability in Phormidium mats and associated anatoxin a and homoanatoxin a in two new zealand rivers
Aquatic Microbial Ecology, 2011Co-Authors: Mark W. Heath, Susanna A. Wood, Ken G. RyanAbstract:Toxic benthic cyanobacterial proliferations in freshwater are becoming increasingly prevalent, and associated animal poisonings are being reported with greater regularity. Despite this, few studies have investigated spatial and temporal variations in freshwater mat-forming Cyanobac- teria and their associated toxin production. Some sections of the Hutt and Wainuiomata rivers (lower North Island, New Zealand) contain extensive Phormidium sp. proliferations that sometimes produce anatoxin-a (ATX) and homoanatoxin-a (HTX). The percentage coverage of Phormidium sp., ATX and/or HTX concentrations and a suite of physicochemical parameters were monitored at 8 sites for 12 mo. The percentage coverage of Phormidium mats was greater in the summer months and these correlated with warmer water temperatures and stable river flows. Flows in excess of 3 times the mean resulted in the removal of Phormidium mats. There was no correlation between the presence/absence of Phormidium mats and water-soluble nutrients. The presence and concentration of ATX and/or HTX and their degradation products, dihydroanatoxin-a and dihydrohomoanatoxin-a, was highly variable across all sites and over time. Anatoxin-a and HTX occurrence was restricted to periods of warm water temperatures (above 13.4°C) and below average river flows.