Fabbro, LD ORCiD: 0000-0001-8893-5115; Rockloff, SF ORCiD: 0000-0003-1293-1884; Taylor, BA ORCiD:... more Fabbro, LD ORCiD: 0000-0001-8893-5115; Rockloff, SF ORCiD: 0000-0003-1293-1884; Taylor, BA ORCiD: 0000-0002-8229-3964Urbanisation has altered streamflow and severely degraded our natural aquatic ecosystems. It is vital that we look beyond studies of water quality and hydrogeomorphology and into natural baseflow regimes and whether restoration is possible to within the ecological limits. This review paper examines empirical studies of water sensitive urban design (WSUD) projects which report improvements to baseflow. It is apparent that baseflow is critical to stream health; however, it is inconclusive that current WSUD practices can systematically restore baseflow to within the natural ecological limits. Fortunately, a solution could exist by increasing infiltration within allotments and by expanding WSUD objectives
Seasonal changes in hydrology are important factors influencing abiotic conditions and subsequent... more Seasonal changes in hydrology are important factors influencing abiotic conditions and subsequently the biota. Although these effects have been studied in tropical catchments and in central arid Australia, subtropical ephemeral streams have largely been ignored. In the present study, three ephemeral streams in Central Queensland were monitored over 15 months. We hypothesised that macroinvertebrate abundance would increase gradually following the initial flow pulse and that abundance would increase until the pools began drying, with sensitive taxa only present during higher flow. In all, 69 families from 14 orders were collected in 128 samples. Significant relationships were not detected between low flow conditions and taxa richness (P>0.05). Principal component analysis showed that the macroinvertebrate communities did not change in response to the drying of pools. Significant differences were not observed between taxa richness, abundance nor tolerant taxa during varied periods o...
Mitigation of cyanobacterial or "blue-green algal" blooms is a challenging task for wat... more Mitigation of cyanobacterial or "blue-green algal" blooms is a challenging task for water managers across Australia. In the present study, a regional drinking water source (located in Central Queensland) was studied to identify the potential risks posed by cyanobacteria. Data were collected from the drinking water source (a lagoon) as well as the drinking water supply infrastructure, at monthly intervals between September 2012 and December 2014. In March 2013 there was an extreme rainfall event where floodwaters infiltrated the water supply without passing through bank filtration. The floodwaters also compromised the bank filtration via erosion. The pump well and bank filtration system were subsequently upgraded/maintained in May 2013. Results showed that following the extreme event and infrastructure upgrade, two distinct Limnothrix redekei blooms microscopically identified, were detected in the drinking water supply chain. Further investigations indicated that the specie...
Coal excavation and refinement processes generate substantial volumes of contaminated effluent th... more Coal excavation and refinement processes generate substantial volumes of contaminated effluent that may be detrimental to aquatic ecosystems. As such, understanding the impacts of coal mine water releases on aquatic animals and ecosystems is essential for effectively managing and protecting neighboring environments. Such information will ultimately be applied towards developing ongoing monitoring strategies that are protective of native wildlife. Despite intensive mining operations in Australia, few studies have documented toxicity associated with coal mine wastewater (CMW) on native species. To address existing knowledge gaps, we investigated acute toxicity (48-96 h) using eight native invertebrate species and sub-chronic effects (2 week) using three vertebrate species following exposure to wastewater from two dams (CMW1 and CMW2) located at an open-cut coal mine licensed to discharge into the Fitzroy catchment (Queensland, Australia). Wastewater from these sites is characterized by elevated conductivity, pH, sulfates as well as relatively high total and dissolved metal(loid)s (including As, Al, B, Cu, Mn, Ni, Se and Zn). Acute exposures revealed cladocerans (Daphnia carinata) and planarians (Dugesia sp.) to be the most sensitive species, exhibiting significant mortality after 48 and 96 h exposure to CMW2, respectively. Neither wastewater was found to elicit acute toxicity in vertebrates, but a range of sub-lethal morphological effects were observed following the sub-chronic exposures. The overall response pattern was characterized by decreased condition factor and hepatosomatic index in the fish Hypseleotris compressa and Pseudomugil signifier, and in Limnodynastes peronii tadpoles. Tadpoles were generally more sensitive compared to the two fish species. Differences in responses were observed amongst CMW1 and CMW2, which likely relates to differences in physico-chemical properties between sites. Our results have identified several candidate vertebrate and invertebrate species that show promise for ongoing monitoring of water quality and toxicity risk in Central Queensland, Australia.
Abstract Microalgae are a varied group of organisms with considerable commercial potential as sou... more Abstract Microalgae are a varied group of organisms with considerable commercial potential as sources of various biochemicals, storage molecules and metabolites such as lipids, sugars, amino acids, pigments and toxins. Algal lipids can be processed to bio-oils and biodiesel. The conventional method to estimate algal lipids is based on extraction using solvents and quantification by gravimetry or chromatography. Such methods are time consuming, use hazardous chemicals and are labor intensive. For rapid screening of prospective algae or for management decisions (e.g. decision on timing of harvest), a rapid, high throughput, reliable, accurate, cost effective and preferably nondestructive analytical technique is desirable. This manuscript reviews the application of fluorescent lipid soluble dyes (Nile Red and BODIPY 505/515), nuclear magnetic resonance (NMR), Raman, Fourier transform infrared (FTIR) and near infrared (NIR) spectroscopy for the assessment of lipids in microalgae.
Sub-lethal toxicological responses are common occurrences in aquatic animals exposed to sewage wa... more Sub-lethal toxicological responses are common occurrences in aquatic animals exposed to sewage wastewater and organic wastewater contaminants. Behavioural alterations are particularly sensitive indicators of sub-lethal toxicological stress in animals exposed to various pollutants, and often correlate with higher-level outcomes. Diurnal activity patterns in many fish species are sensitive to changes in natural biotic factors, but few studies have explored how environmental pollutants influence such rhythms. We investigated diurnal activity patterns in the mosquitofish (Gambusia holbrooki), after exposure to UV-treated sewage and a mixture of key contaminants identified through chemical analysis and subsequent risk-based prioritization of the wastewater. Exposure to 50% and 100% wastewater abolished daytime activity levels in male, but not female fish. Chemical analysis identified fluoxetine, diazinon and triclosan above their reported predicted-no-effect-concentrations (PNECs), and fish were thus exposed to a mixture of these compounds at 1, 10 and 100 μg l-1. Behavioural responses were highly consistent between fish exposed to wastewater and the contaminant mixture, indicating that these prioritized contaminants are indeed likely contributing to the observed effects. Effective concentrations of the mixture were considerably lower than those reported as eliciting behavioural effects in previous studies exploring each of these compounds alone. Results warn of the potential for negative higher-level consequences associated with exposures of fish to common organic wastewater contaminants, as altered diurnal activity patterns could conceivably scale-up to influence performance including foraging success and predator avoidance. Further research is necessary to increase our understanding of linkages between alterations to diurnal activities and effects at the population level.
h i g h l i g h t s • Research undertaken in southern Great Barrier Reef World Heritage Area. • P... more h i g h l i g h t s • Research undertaken in southern Great Barrier Reef World Heritage Area. • Profound water quality changes at Capricorn Coast associated with Fitzroy River outflows. • Phyto-pigment composition related to water quality using multivariate analyses. • Phyto-pigments depict presence of cyanobacteria, diatoms, and green flagellates. • DSi:DIN foremost in defining phytoplankton assemblages indicated by phyto-pigments.
Coal mining generates large quantities of complex effluent and may pose a threat to aquatic wildl... more Coal mining generates large quantities of complex effluent and may pose a threat to aquatic wildlife. Despite this, few studies have explored the consequences of exposure to mine wastewater on aquatic organisms, and this is particularly true for the Australian environment. We investigated sub-lethal behavioural responses in a native Australian fish exposed to wastewater from two releasing dams (CMW1 and CMW2) located at an open cut coal mine in Central Queensland. Swimming activity and movement of empire gudgeons (Hypseleotris compressa) were assessed during a two-week exposure using video-tracking software. Increased activity was observed in exposed fish after 7 and 14 days. Specifically, we found a significant increase in the mean velocity and mobility of fish exposed to CMW1 treatments. Exposed fish also spent on average 23% more time in the peripheral zone compared to controls after 14-d exposures. A similar response pattern was observed in fish exposed to CMW2, but differences ...
The dynamic interplay between physical, chemical and biological factors in the development and pe... more The dynamic interplay between physical, chemical and biological factors in the development and persistence of cyanobacterial blooms in impounded rivers is an important topic. Over a 3-year study period, variable climatic conditions were recorded in the Fitzroy River, Queensland, Australia, which is a typical, impounded lowland tropical river. Post-flood turbidity reduced the available light in the well-mixed water column to levels insufficient for cyanobacterial growth. Only when the water column stratified and the slowly sinking particles dropped from the surface layer did the ratio of surface mixed layer depth to euphotic depth approach 1, allowing cyanobacterial growth. By the time the light climate became favorable, most of the dissolved nutrients had been scavenged from the water column by settling particles or sequestered by fringing macrophytes and other biogeochemical processes. Cyanobacterial blooms dominated by Cylindrospermopsis raciborskii persisted for several months un...
A growing list of freshwater cyanobacteria are known to produce toxic agents, a fact which makes ... more A growing list of freshwater cyanobacteria are known to produce toxic agents, a fact which makes these organisms of concern to water authorities. A cultured strain of Limnothrix (AC0243) was recently shown to have toxic effects in in vitro bioassays. It did not produce any of the known cyanobacterial toxins. The intrapertoneal toxicity of aqueous extracts of the material was therefore tested in mice to determine whether the observed effects might be of public health relevance to drinking water supplies. The results indicate that Limnothrix AC0243 is acutely toxic to mice, causing widespread cellular necrosis in the liver, kidneys and gastrointestinal tract within 24 h of exposure. Sub-lethal effects lasted at least 7 d. These results suggest that Limnothrix AC0243 produces a novel toxin ("Limnothrixin") and that further work is therefore urgently required to quantify the potential public health implications.
Fabbro, LD ORCiD: 0000-0001-8893-5115The Fitzroy catchment in Central populated region. This, the... more Fabbro, LD ORCiD: 0000-0001-8893-5115The Fitzroy catchment in Central populated region. This, the largest east coast Australian catchment, consists of several sub-basins including the Connors, Isaac, Nogoa, Mackenzie, Comet and Dawson.Rainfall and streamflows in the region are highly variable with the mean annual discharge of the Fitzroy River past Rockhampton into the southern lagoon the Great Barrier Reef being about 5 million megalitres (ML)
The dynamic interplay between physical, chemical and biological factors in the development and pe... more The dynamic interplay between physical, chemical and biological factors in the development and persistence of cyanobacterial blooms in impounded rivers is an important topic. Over a 3-year study period, variable climatic conditions were recorded in the Fitzroy River, Queensland, Australia, which is a typical, impounded lowland tropical river. Post-flood turbidity reduced the available light in the well-mixed water column to levels insufficient for cyanobacterial growth. Only when the water column stratified and the slowly sinking particles dropped from the surface layer did the ratio of surface mixed layer depth to euphotic depth approach 1, allowing cyanobacterial growth. By the time the light climate became favorable, most of the dissolved nutrients had been scavenged from the water column by settling particles or sequestered by fringing macrophytes and other biogeochemical processes. Cyanobacterial blooms dominated by Cylindrospermopsis raciborskii persisted for several months until the next flood flushed the system. The cyanobacterial species dominating that environment were very small and had high specific phosphorus uptake rates. Their nutrient requirement was met by transfer across the oxycline driven by regular high wind mixing events, entraining nutrient-rich bottom waters. Nutrient fluxes from the sediments into the anoxic bottom layer were sufficient to replace the bottom nutrients lost to the surface layer. M F 0 3 0 4 5 C y a n o b a c t e r i a l b l o o m s i n a t r o p i c a l r i v e r M . B o r m a n s e t a l .
Ecotoxicology and environmental safety, Jan 18, 2016
Coal mining represents an important industry in many countries, but concerns exist about the poss... more Coal mining represents an important industry in many countries, but concerns exist about the possible adverse effects of minewater releases on aquatic animals and ecosystems. Coal mining generates large volumes of complex wastewater, which often contains high concentrations of dissolved solids, suspended solids, metals, hydrocarbons, salts and other compounds. Traditional toxicological testing has generally involved the assessment of acute toxicity or chronic toxicity with longer-term tests, and while such tests provide useful information, they are poorly suited to ongoing monitoring or rapid assessment following accidental discharge events. As such, there is considerable interest in developing rapid and sensitive approaches to environmental monitoring, and particularly involving the assessment of sub-lethal behavioural responses in locally relevant aquatic species. We therefore investigated behavioural responses of a native Australian fish to coal mine wastewater, to evaluate its p...
Juvenile empire gudgeons were exposed to coal mine wastewater from two dams. Increased activity w... more Juvenile empire gudgeons were exposed to coal mine wastewater from two dams. Increased activity was observed in exposed fish after 7 and 14 days. Exposed fish generally spent more time in the peripheral zone after 14 days. a b s t r a c t Coal mining generates large quantities of complex effluent and may pose a threat to aquatic wildlife. Despite this, few studies have explored the consequences of exposure to mine wastewater on aquatic organisms, and this is particularly true for the Australian environment. We investigated sub-lethal behavioural responses in a native Australian fish exposed to wastewater from two releasing dams (CMW1 and CMW2) located at an open cut coal mine in Central Queensland. Swimming activity and movement of empire gudgeons (Hypseleotris compressa) were assessed during a two-week exposure using video-tracking software. Increased activity was observed in exposed fish after 7 and 14 days. Specifically, we found a significant increase in the mean velocity and mobility of fish exposed to CMW1 treatments. Exposed fish also spent on average 23% more time in the peripheral zone compared to controls after 14-d exposures. A similar response pattern was observed in fish exposed to CMW2, but differences between treated and control fish did not generally reach statistical significance. Alterations to normal swimming activity and movement patterns can be indicative of a stress response in fish, and could subsequently lead to negative population-level impacts by increasing the conspicuousness of exposed individuals to predators, or by altering foraging abilities. More research is warranted to explore relationships between behavioural and physiological outcomes, including endocrine disruption, and subsequent population-level outcomes in aquatic organisms at risk of exposure to coal process-affected water.
This paper describes the vertical water column distribution of the cyanobacterial toxins cylindro... more This paper describes the vertical water column distribution of the cyanobacterial toxins cylindrospermopsin and deoxycylindrospermopsin in a water body containing the cyanobacteria Aphanizomenon ovalisporum and Cylindrospermopsis raciborskii. The study site was Cobaki Village Lake, a small stratified anthropogenic lake in north-eastern New South Wales, Australia. Water quality analysis indicated that stratification and oxygenation of the water column were significant in both the distribution of the cyanobacterial populations and their associated toxin concentrations. Toxin was distributed throughout the entire water column, but the highest concentrations were recorded in the hypolimnion. Maximum toxin concentrations were detected in February 2007 (38.2 µg L −1 cylindrospermopsin (CYN) and 42.2 µg L −1 deoxy-CYN). The relative distribution of CYN and deoxy-CYN paralleled the distribution of NH 3 H and NO X within the water column, with oxygenated chemical species dominating above 15 m and de-oxygenated chemical species dominating below 15 m. Cyanobacterial cell concentrations were highest in the oxic, warm and low conductivity waters of the epilimnion and cyanobacterial species succession was associated with nutrient and trace-metal depletion in this surface layer. These research findings are directly relevant to the management of water supplies affected by toxic blue-green algal blooms, particularly with respect to the considered placement of off-take devices to avoid layers of cyanobacterial cell and toxin concentrations.
Sublethal effects in the aquatic snail Melanoides tuberculata were examined during exposure to wh... more Sublethal effects in the aquatic snail Melanoides tuberculata were examined during exposure to whole cell extracts of Cylindrospermopsis raciborskii and live C. raciborskii cultures, containing varying concentrations of algal cells, cellular debris, and the blue-...
This paper describes the species-specific responses recorded from two toxin-producing cyanobacter... more This paper describes the species-specific responses recorded from two toxin-producing cyanobacteria Aphanizomenon ovalisporum(Forti) and Cylindrospermopsis raciborskii (Woloszynska) Seenaya and Subba Raju as they approached an overwintering phase in Cobaki Lake (New South ...
Fabbro, LD ORCiD: 0000-0001-8893-5115; Rockloff, SF ORCiD: 0000-0003-1293-1884; Taylor, BA ORCiD:... more Fabbro, LD ORCiD: 0000-0001-8893-5115; Rockloff, SF ORCiD: 0000-0003-1293-1884; Taylor, BA ORCiD: 0000-0002-8229-3964Urbanisation has altered streamflow and severely degraded our natural aquatic ecosystems. It is vital that we look beyond studies of water quality and hydrogeomorphology and into natural baseflow regimes and whether restoration is possible to within the ecological limits. This review paper examines empirical studies of water sensitive urban design (WSUD) projects which report improvements to baseflow. It is apparent that baseflow is critical to stream health; however, it is inconclusive that current WSUD practices can systematically restore baseflow to within the natural ecological limits. Fortunately, a solution could exist by increasing infiltration within allotments and by expanding WSUD objectives
Seasonal changes in hydrology are important factors influencing abiotic conditions and subsequent... more Seasonal changes in hydrology are important factors influencing abiotic conditions and subsequently the biota. Although these effects have been studied in tropical catchments and in central arid Australia, subtropical ephemeral streams have largely been ignored. In the present study, three ephemeral streams in Central Queensland were monitored over 15 months. We hypothesised that macroinvertebrate abundance would increase gradually following the initial flow pulse and that abundance would increase until the pools began drying, with sensitive taxa only present during higher flow. In all, 69 families from 14 orders were collected in 128 samples. Significant relationships were not detected between low flow conditions and taxa richness (P>0.05). Principal component analysis showed that the macroinvertebrate communities did not change in response to the drying of pools. Significant differences were not observed between taxa richness, abundance nor tolerant taxa during varied periods o...
Mitigation of cyanobacterial or "blue-green algal" blooms is a challenging task for wat... more Mitigation of cyanobacterial or "blue-green algal" blooms is a challenging task for water managers across Australia. In the present study, a regional drinking water source (located in Central Queensland) was studied to identify the potential risks posed by cyanobacteria. Data were collected from the drinking water source (a lagoon) as well as the drinking water supply infrastructure, at monthly intervals between September 2012 and December 2014. In March 2013 there was an extreme rainfall event where floodwaters infiltrated the water supply without passing through bank filtration. The floodwaters also compromised the bank filtration via erosion. The pump well and bank filtration system were subsequently upgraded/maintained in May 2013. Results showed that following the extreme event and infrastructure upgrade, two distinct Limnothrix redekei blooms microscopically identified, were detected in the drinking water supply chain. Further investigations indicated that the specie...
Coal excavation and refinement processes generate substantial volumes of contaminated effluent th... more Coal excavation and refinement processes generate substantial volumes of contaminated effluent that may be detrimental to aquatic ecosystems. As such, understanding the impacts of coal mine water releases on aquatic animals and ecosystems is essential for effectively managing and protecting neighboring environments. Such information will ultimately be applied towards developing ongoing monitoring strategies that are protective of native wildlife. Despite intensive mining operations in Australia, few studies have documented toxicity associated with coal mine wastewater (CMW) on native species. To address existing knowledge gaps, we investigated acute toxicity (48-96 h) using eight native invertebrate species and sub-chronic effects (2 week) using three vertebrate species following exposure to wastewater from two dams (CMW1 and CMW2) located at an open-cut coal mine licensed to discharge into the Fitzroy catchment (Queensland, Australia). Wastewater from these sites is characterized by elevated conductivity, pH, sulfates as well as relatively high total and dissolved metal(loid)s (including As, Al, B, Cu, Mn, Ni, Se and Zn). Acute exposures revealed cladocerans (Daphnia carinata) and planarians (Dugesia sp.) to be the most sensitive species, exhibiting significant mortality after 48 and 96 h exposure to CMW2, respectively. Neither wastewater was found to elicit acute toxicity in vertebrates, but a range of sub-lethal morphological effects were observed following the sub-chronic exposures. The overall response pattern was characterized by decreased condition factor and hepatosomatic index in the fish Hypseleotris compressa and Pseudomugil signifier, and in Limnodynastes peronii tadpoles. Tadpoles were generally more sensitive compared to the two fish species. Differences in responses were observed amongst CMW1 and CMW2, which likely relates to differences in physico-chemical properties between sites. Our results have identified several candidate vertebrate and invertebrate species that show promise for ongoing monitoring of water quality and toxicity risk in Central Queensland, Australia.
Abstract Microalgae are a varied group of organisms with considerable commercial potential as sou... more Abstract Microalgae are a varied group of organisms with considerable commercial potential as sources of various biochemicals, storage molecules and metabolites such as lipids, sugars, amino acids, pigments and toxins. Algal lipids can be processed to bio-oils and biodiesel. The conventional method to estimate algal lipids is based on extraction using solvents and quantification by gravimetry or chromatography. Such methods are time consuming, use hazardous chemicals and are labor intensive. For rapid screening of prospective algae or for management decisions (e.g. decision on timing of harvest), a rapid, high throughput, reliable, accurate, cost effective and preferably nondestructive analytical technique is desirable. This manuscript reviews the application of fluorescent lipid soluble dyes (Nile Red and BODIPY 505/515), nuclear magnetic resonance (NMR), Raman, Fourier transform infrared (FTIR) and near infrared (NIR) spectroscopy for the assessment of lipids in microalgae.
Sub-lethal toxicological responses are common occurrences in aquatic animals exposed to sewage wa... more Sub-lethal toxicological responses are common occurrences in aquatic animals exposed to sewage wastewater and organic wastewater contaminants. Behavioural alterations are particularly sensitive indicators of sub-lethal toxicological stress in animals exposed to various pollutants, and often correlate with higher-level outcomes. Diurnal activity patterns in many fish species are sensitive to changes in natural biotic factors, but few studies have explored how environmental pollutants influence such rhythms. We investigated diurnal activity patterns in the mosquitofish (Gambusia holbrooki), after exposure to UV-treated sewage and a mixture of key contaminants identified through chemical analysis and subsequent risk-based prioritization of the wastewater. Exposure to 50% and 100% wastewater abolished daytime activity levels in male, but not female fish. Chemical analysis identified fluoxetine, diazinon and triclosan above their reported predicted-no-effect-concentrations (PNECs), and fish were thus exposed to a mixture of these compounds at 1, 10 and 100 μg l-1. Behavioural responses were highly consistent between fish exposed to wastewater and the contaminant mixture, indicating that these prioritized contaminants are indeed likely contributing to the observed effects. Effective concentrations of the mixture were considerably lower than those reported as eliciting behavioural effects in previous studies exploring each of these compounds alone. Results warn of the potential for negative higher-level consequences associated with exposures of fish to common organic wastewater contaminants, as altered diurnal activity patterns could conceivably scale-up to influence performance including foraging success and predator avoidance. Further research is necessary to increase our understanding of linkages between alterations to diurnal activities and effects at the population level.
h i g h l i g h t s • Research undertaken in southern Great Barrier Reef World Heritage Area. • P... more h i g h l i g h t s • Research undertaken in southern Great Barrier Reef World Heritage Area. • Profound water quality changes at Capricorn Coast associated with Fitzroy River outflows. • Phyto-pigment composition related to water quality using multivariate analyses. • Phyto-pigments depict presence of cyanobacteria, diatoms, and green flagellates. • DSi:DIN foremost in defining phytoplankton assemblages indicated by phyto-pigments.
Coal mining generates large quantities of complex effluent and may pose a threat to aquatic wildl... more Coal mining generates large quantities of complex effluent and may pose a threat to aquatic wildlife. Despite this, few studies have explored the consequences of exposure to mine wastewater on aquatic organisms, and this is particularly true for the Australian environment. We investigated sub-lethal behavioural responses in a native Australian fish exposed to wastewater from two releasing dams (CMW1 and CMW2) located at an open cut coal mine in Central Queensland. Swimming activity and movement of empire gudgeons (Hypseleotris compressa) were assessed during a two-week exposure using video-tracking software. Increased activity was observed in exposed fish after 7 and 14 days. Specifically, we found a significant increase in the mean velocity and mobility of fish exposed to CMW1 treatments. Exposed fish also spent on average 23% more time in the peripheral zone compared to controls after 14-d exposures. A similar response pattern was observed in fish exposed to CMW2, but differences ...
The dynamic interplay between physical, chemical and biological factors in the development and pe... more The dynamic interplay between physical, chemical and biological factors in the development and persistence of cyanobacterial blooms in impounded rivers is an important topic. Over a 3-year study period, variable climatic conditions were recorded in the Fitzroy River, Queensland, Australia, which is a typical, impounded lowland tropical river. Post-flood turbidity reduced the available light in the well-mixed water column to levels insufficient for cyanobacterial growth. Only when the water column stratified and the slowly sinking particles dropped from the surface layer did the ratio of surface mixed layer depth to euphotic depth approach 1, allowing cyanobacterial growth. By the time the light climate became favorable, most of the dissolved nutrients had been scavenged from the water column by settling particles or sequestered by fringing macrophytes and other biogeochemical processes. Cyanobacterial blooms dominated by Cylindrospermopsis raciborskii persisted for several months un...
A growing list of freshwater cyanobacteria are known to produce toxic agents, a fact which makes ... more A growing list of freshwater cyanobacteria are known to produce toxic agents, a fact which makes these organisms of concern to water authorities. A cultured strain of Limnothrix (AC0243) was recently shown to have toxic effects in in vitro bioassays. It did not produce any of the known cyanobacterial toxins. The intrapertoneal toxicity of aqueous extracts of the material was therefore tested in mice to determine whether the observed effects might be of public health relevance to drinking water supplies. The results indicate that Limnothrix AC0243 is acutely toxic to mice, causing widespread cellular necrosis in the liver, kidneys and gastrointestinal tract within 24 h of exposure. Sub-lethal effects lasted at least 7 d. These results suggest that Limnothrix AC0243 produces a novel toxin ("Limnothrixin") and that further work is therefore urgently required to quantify the potential public health implications.
Fabbro, LD ORCiD: 0000-0001-8893-5115The Fitzroy catchment in Central populated region. This, the... more Fabbro, LD ORCiD: 0000-0001-8893-5115The Fitzroy catchment in Central populated region. This, the largest east coast Australian catchment, consists of several sub-basins including the Connors, Isaac, Nogoa, Mackenzie, Comet and Dawson.Rainfall and streamflows in the region are highly variable with the mean annual discharge of the Fitzroy River past Rockhampton into the southern lagoon the Great Barrier Reef being about 5 million megalitres (ML)
The dynamic interplay between physical, chemical and biological factors in the development and pe... more The dynamic interplay between physical, chemical and biological factors in the development and persistence of cyanobacterial blooms in impounded rivers is an important topic. Over a 3-year study period, variable climatic conditions were recorded in the Fitzroy River, Queensland, Australia, which is a typical, impounded lowland tropical river. Post-flood turbidity reduced the available light in the well-mixed water column to levels insufficient for cyanobacterial growth. Only when the water column stratified and the slowly sinking particles dropped from the surface layer did the ratio of surface mixed layer depth to euphotic depth approach 1, allowing cyanobacterial growth. By the time the light climate became favorable, most of the dissolved nutrients had been scavenged from the water column by settling particles or sequestered by fringing macrophytes and other biogeochemical processes. Cyanobacterial blooms dominated by Cylindrospermopsis raciborskii persisted for several months until the next flood flushed the system. The cyanobacterial species dominating that environment were very small and had high specific phosphorus uptake rates. Their nutrient requirement was met by transfer across the oxycline driven by regular high wind mixing events, entraining nutrient-rich bottom waters. Nutrient fluxes from the sediments into the anoxic bottom layer were sufficient to replace the bottom nutrients lost to the surface layer. M F 0 3 0 4 5 C y a n o b a c t e r i a l b l o o m s i n a t r o p i c a l r i v e r M . B o r m a n s e t a l .
Ecotoxicology and environmental safety, Jan 18, 2016
Coal mining represents an important industry in many countries, but concerns exist about the poss... more Coal mining represents an important industry in many countries, but concerns exist about the possible adverse effects of minewater releases on aquatic animals and ecosystems. Coal mining generates large volumes of complex wastewater, which often contains high concentrations of dissolved solids, suspended solids, metals, hydrocarbons, salts and other compounds. Traditional toxicological testing has generally involved the assessment of acute toxicity or chronic toxicity with longer-term tests, and while such tests provide useful information, they are poorly suited to ongoing monitoring or rapid assessment following accidental discharge events. As such, there is considerable interest in developing rapid and sensitive approaches to environmental monitoring, and particularly involving the assessment of sub-lethal behavioural responses in locally relevant aquatic species. We therefore investigated behavioural responses of a native Australian fish to coal mine wastewater, to evaluate its p...
Juvenile empire gudgeons were exposed to coal mine wastewater from two dams. Increased activity w... more Juvenile empire gudgeons were exposed to coal mine wastewater from two dams. Increased activity was observed in exposed fish after 7 and 14 days. Exposed fish generally spent more time in the peripheral zone after 14 days. a b s t r a c t Coal mining generates large quantities of complex effluent and may pose a threat to aquatic wildlife. Despite this, few studies have explored the consequences of exposure to mine wastewater on aquatic organisms, and this is particularly true for the Australian environment. We investigated sub-lethal behavioural responses in a native Australian fish exposed to wastewater from two releasing dams (CMW1 and CMW2) located at an open cut coal mine in Central Queensland. Swimming activity and movement of empire gudgeons (Hypseleotris compressa) were assessed during a two-week exposure using video-tracking software. Increased activity was observed in exposed fish after 7 and 14 days. Specifically, we found a significant increase in the mean velocity and mobility of fish exposed to CMW1 treatments. Exposed fish also spent on average 23% more time in the peripheral zone compared to controls after 14-d exposures. A similar response pattern was observed in fish exposed to CMW2, but differences between treated and control fish did not generally reach statistical significance. Alterations to normal swimming activity and movement patterns can be indicative of a stress response in fish, and could subsequently lead to negative population-level impacts by increasing the conspicuousness of exposed individuals to predators, or by altering foraging abilities. More research is warranted to explore relationships between behavioural and physiological outcomes, including endocrine disruption, and subsequent population-level outcomes in aquatic organisms at risk of exposure to coal process-affected water.
This paper describes the vertical water column distribution of the cyanobacterial toxins cylindro... more This paper describes the vertical water column distribution of the cyanobacterial toxins cylindrospermopsin and deoxycylindrospermopsin in a water body containing the cyanobacteria Aphanizomenon ovalisporum and Cylindrospermopsis raciborskii. The study site was Cobaki Village Lake, a small stratified anthropogenic lake in north-eastern New South Wales, Australia. Water quality analysis indicated that stratification and oxygenation of the water column were significant in both the distribution of the cyanobacterial populations and their associated toxin concentrations. Toxin was distributed throughout the entire water column, but the highest concentrations were recorded in the hypolimnion. Maximum toxin concentrations were detected in February 2007 (38.2 µg L −1 cylindrospermopsin (CYN) and 42.2 µg L −1 deoxy-CYN). The relative distribution of CYN and deoxy-CYN paralleled the distribution of NH 3 H and NO X within the water column, with oxygenated chemical species dominating above 15 m and de-oxygenated chemical species dominating below 15 m. Cyanobacterial cell concentrations were highest in the oxic, warm and low conductivity waters of the epilimnion and cyanobacterial species succession was associated with nutrient and trace-metal depletion in this surface layer. These research findings are directly relevant to the management of water supplies affected by toxic blue-green algal blooms, particularly with respect to the considered placement of off-take devices to avoid layers of cyanobacterial cell and toxin concentrations.
Sublethal effects in the aquatic snail Melanoides tuberculata were examined during exposure to wh... more Sublethal effects in the aquatic snail Melanoides tuberculata were examined during exposure to whole cell extracts of Cylindrospermopsis raciborskii and live C. raciborskii cultures, containing varying concentrations of algal cells, cellular debris, and the blue-...
This paper describes the species-specific responses recorded from two toxin-producing cyanobacter... more This paper describes the species-specific responses recorded from two toxin-producing cyanobacteria Aphanizomenon ovalisporum(Forti) and Cylindrospermopsis raciborskii (Woloszynska) Seenaya and Subba Raju as they approached an overwintering phase in Cobaki Lake (New South ...
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