975 results on '"harmful algae"'
Search Results
202. Growth, Toxin Production and Allelopathic Effects of Pseudo-nitzschia multiseries under Iron-Enriched Conditions
- Author
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Bruna Fernanda Sobrinho, Luana Mocelin de Camargo, Leonardo Sandrini-Neto, Cristian Rafael Kleemann, Eunice da Costa Machado, and Luiz Laureno Mafra
- Subjects
harmful algae ,toxic diatoms ,domoic acid ,phycotoxins ,allelopathy ,iron fertilization ,Biology (General) ,QH301-705.5 - Abstract
In order to assess the effects of Fe-enrichment on the growth and domoic acid (DA) production of the toxigenic diatom Pseudo-nitzschia multiseries, static cultures that received the addition of different iron (Fe) concentrations were maintained for 30 days. Intra- and extracellular DA concentrations were evaluated over time, and growth and chain-formation were compared to those of non-toxic diatoms, Bacillaria sp. Growth rates of P. multiseries (μ = 0.45–0.73 d−1) were similar among cultures containing different Fe concentrations. Likewise, the similar incidence and length of P. multiseries stepped cell chains (usually 2–4; up to 8-cell long) among the treatments reinforces that the cultures were not growth-inhibited under any condition tested, suggesting an efficient Fe acquisition mechanism. Moreover, DA concentrations were significantly higher under the highest Fe concentration, indicating that Fe is required for toxin synthesis. Bacillaria sp. reached comparable growth rates under the same Fe concentrations, except when the dissolved cell contents from a P. multiseries culture was added. The 50–70% reduction in cell density and 70–90% decrease in total chlorophyll-a content of Bacillaria sp. at early stationary growth phase indicates, for the first time, an allelopathic effect of undetermined compounds released by Pseudo-nitzschia to another diatom species.
- Published
- 2017
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203. Screening the toxicity and toxin content of blooms of the cyanobacterium Trichodesmium erythraeum (Ehrenberg) in northeast Brasil
- Author
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LAO Proença, MS Tamanaha, and RS Fonseca
- Subjects
saxitoxin ,microcystin ,harmful algae ,Trichodesmium ,bloom ,Arctic medicine. Tropical medicine ,RC955-962 ,Toxicology. Poisons ,RA1190-1270 ,Zoology ,QL1-991 - Abstract
Blooms of the cyanobacterium Trichodesmium occur in massive colored patches over large areas of tropical and subtropical oceans. Recently, the interest in such events has increased given their role in major nitrogen and carbon dioxide oceanic fluxes. Trichodesmium occurs all along the Brazilian coast and patches frequently migrate towards the coast. In this paper we screen the toxicity and toxin content of Trichodesmium blooms off the coast of Bahia state. Four samples, collected from February to April 2007, were analyzed. Organisms were identified and assessed for toxicity by means of several methods. Analogues of microcystins, cylindrospermopsins and saxitoxins were analyzed using HPLC. Microcystins were also assayed through ELISA. Results showed dominance of T. erythraeum, which makes up as much as 99% of cell counts. Other organisms found in smaller quantities include the dinoflagellates Prorocentrum minimum and P. rhathymum. Extracts from all samples delayed or interrupted sea urchin larval development, but presented no acute toxicity during a mouse bioassay. Saxitoxin congeners and microcystins were present at low concentrations in all samples, occurrences that had not previously been reported in the literature. Despite our finding of saxitoxin analogues and microcystins in Trichodesmium blooms, these toxins do not represent a potential harm to human health by primary contact. We conclude, based on our results and those reported in the recent literature, which differ from results published in 1963, that although toxins are present, there is no evidence that T. erythraeum blooms represent a threat to humans.
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- 2009
- Full Text
- View/download PDF
204. Impacts of ocean acidification on growth and toxin content of the marine diatoms Pseudo-nitzschia australis and P. fraudulenta
- Abstract
This paper present the effects of ocean acidification on growth and domoic acid (DA) content of several strains of the toxic Pseudo-nitzschia australis and the non-toxic P. fraudulenta. Three strains of each species (plus two subclones of P. australis) were acclimated and grown in semi-continuous cultures at three pH levels: 8.07, 7.77, and 7.40, in order to simulate changes of seawater pH from present to plausible future levels. Our results showed that lowering pH from current level (8.07) to predicted pH level in 2100 (7.77) did not affect the mean growth rates of some of the P. australis strains (FR-PAU-17 and L3-100), but affected other strains either negatively (L3-30) or positively (L3.4). However, the growth rates significantly decreased with pH lowered to 7.40 (by 13% for L3-100, 43% for L3-30 and 16% for IFR-PAU-17 compared to the rates at pH 8.07). In contrast, growth rates of the non-toxic P. fraudulenta strains were not affected by pH changing from 8.07 to 7.40. The P. australis strains produced DA at all pH levels tested, and the highest particulate DA concentration normalized to cell abundance (pDA) was found at pH 8.07. Total DA content (pDA and dissolved DA) was significantly higher at current pH (8.07) compared to pH (7.77), exept for one strain (L 3.4) where no difference was found. At lower pH levels 7.77–7.40, total DA content was similar, except for strains IFR-PAU-17 and L3-100 which had the lowest content at the pH 7.77. The diversity in the responses in growth and DA content highlights the inter- and intra-specific variation in Pseudo-nitzschia species in response to ocean acidification. When exploring environmental responses of Pseudo-nitzschia using cultured cells, not only strain-specific variation but also culturing history should be taken into consideration, as the light levels under which the subclones were cultured, afterwards affected both maximum growth rates and DA content.
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- 2021
- Full Text
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205. Polyketide synthase genes and molecular trade-offs in the ichthyotoxic species Prymnesium parvum
- Abstract
Prymnesium parvum is a bloom forming haptophyte that has been responsible for numerous fish kill events across the world. The toxicity of P. parvum has been attributed to the production of large polyketide compounds, collectively called prymnesins, which based on their structure can be divided into A-, B- and C-type. The polyketide chemical nature of prymnesins indicates the potential involvement of polyketide synthases (PKSs) in their biosynthesis. However, little is known about the presence of PKSs in P. parvum as well as the potential molecular trade-offs of toxin biosynthesis. In the current study, we generated and analyzed the transcriptomes of nine P. parvum strains that produce different toxin types and have various cellular toxin contents. Numerous type I PKSs, ranging from 37 to 109, were found among the strains. Larger modular type I PKSs were mainly retrieved from strains with high cellular toxin levels and eight consensus transcripts were present in all nine strains. Gene expression variance analysis revealed potential molecular trade-offs associated with cellular toxin quantity, showing that basic metabolic processes seem to correlate negatively with cellular toxin content. These findings point towards the presence of metabolic costs for maintaining high cellular toxin quantity. The detailed analysis of PKSs in P. parvum is the first step towards better understanding the molecular basis of the biosynthesis of prymnesins and contributes to the development of molecular tools for efficient monitoring of future blooms.
- Published
- 2021
206. Impacts of ocean acidification on growth and toxin content of the marine diatoms Pseudo-nitzschia australis and P. fraudulenta
- Abstract
This paper present the effects of ocean acidification on growth and domoic acid (DA) content of several strains of the toxic Pseudo-nitzschia australis and the non-toxic P. fraudulenta. Three strains of each species (plus two subclones of P. australis) were acclimated and grown in semi-continuous cultures at three pH levels: 8.07, 7.77, and 7.40, in order to simulate changes of seawater pH from present to plausible future levels. Our results showed that lowering pH from current level (8.07) to predicted pH level in 2100 (7.77) did not affect the mean growth rates of some of the P. australis strains (FR-PAU-17 and L3-100), but affected other strains either negatively (L3-30) or positively (L3.4). However, the growth rates significantly decreased with pH lowered to 7.40 (by 13% for L3-100, 43% for L3-30 and 16% for IFR-PAU-17 compared to the rates at pH 8.07). In contrast, growth rates of the non-toxic P. fraudulenta strains were not affected by pH changing from 8.07 to 7.40. The P. australis strains produced DA at all pH levels tested, and the highest particulate DA concentration normalized to cell abundance (pDA) was found at pH 8.07. Total DA content (pDA and dissolved DA) was significantly higher at current pH (8.07) compared to pH (7.77), exept for one strain (L 3.4) where no difference was found. At lower pH levels 7.77–7.40, total DA content was similar, except for strains IFR-PAU-17 and L3-100 which had the lowest content at the pH 7.77. The diversity in the responses in growth and DA content highlights the inter- and intra-specific variation in Pseudo-nitzschia species in response to ocean acidification. When exploring environmental responses of Pseudo-nitzschia using cultured cells, not only strain-specific variation but also culturing history should be taken into consideration, as the light levels under which the subclones were cultured, afterwards affected both maximum growth rates and DA content.
- Published
- 2021
207. Impacts of ocean acidification on growth and toxin content of the marine diatoms Pseudo-nitzschia australis and P. fraudulenta
- Abstract
This paper present the effects of ocean acidification on growth and domoic acid (DA) content of several strains of the toxic Pseudo-nitzschia australis and the non-toxic P. fraudulenta. Three strains of each species (plus two subclones of P. australis) were acclimated and grown in semi-continuous cultures at three pH levels: 8.07, 7.77, and 7.40, in order to simulate changes of seawater pH from present to plausible future levels. Our results showed that lowering pH from current level (8.07) to predicted pH level in 2100 (7.77) did not affect the mean growth rates of some of the P. australis strains (FR-PAU-17 and L3-100), but affected other strains either negatively (L3-30) or positively (L3.4). However, the growth rates significantly decreased with pH lowered to 7.40 (by 13% for L3-100, 43% for L3-30 and 16% for IFR-PAU-17 compared to the rates at pH 8.07). In contrast, growth rates of the non-toxic P. fraudulenta strains were not affected by pH changing from 8.07 to 7.40. The P. australis strains produced DA at all pH levels tested, and the highest particulate DA concentration normalized to cell abundance (pDA) was found at pH 8.07. Total DA content (pDA and dissolved DA) was significantly higher at current pH (8.07) compared to pH (7.77), exept for one strain (L 3.4) where no difference was found. At lower pH levels 7.77–7.40, total DA content was similar, except for strains IFR-PAU-17 and L3-100 which had the lowest content at the pH 7.77. The diversity in the responses in growth and DA content highlights the inter- and intra-specific variation in Pseudo-nitzschia species in response to ocean acidification. When exploring environmental responses of Pseudo-nitzschia using cultured cells, not only strain-specific variation but also culturing history should be taken into consideration, as the light levels under which the subclones were cultured, afterwards affected both maximum growth rates and DA content.
- Published
- 2021
- Full Text
- View/download PDF
208. The Latin America and Caribbean HAB status report based on OBIS and HAEDAT maps and databases
- Abstract
Harmful Algae Blooms (HAB) have been documented for at least fifty years in Latin America and the Caribbean (LAC), however, their impacts at social, ecological and economic levels are still little known. To contribute to the impact assessment of HABs in LAC region, the available information in HAEDAT, OBIS, CAREC, and CARPHA databases, and scientific literature was analyzed. This historical analysis allows identification of the main syndromes and causal organisms. Considering the existence of two regional working groups of the Intergovernmental Oceanographic Commission (IOC): Algas Nocivas del Caribe (ANCA) and Floraciones Algales Nocivas en Sudamérica (FANSA), representing Central American/Caribbean and South American countries, respectively, the analysis is presented both globally and subregional. For the FANSA region, the HAEDAT data base listed 249 records from 1970 to 2019, with a total of 1432 human intoxications, including 37 fatalities. The majority of these events comprised Paralytic Shellfish Toxins (49%), Diarrhetic Shellfish Toxins (34%), Cyanotoxins (12%) and 6 % other toxins. The total number of harmful taxa in the OBIS database includes 79 species distributed over 25 genera. The most commonly reported species are Alexandrium catenella/tamarense, Gymnodinium catenatum and the Dinophysis acuminata complex. Two new species Prorocentrum caipirignum Fraga, Menezes and Nascimento and Alexandrium fragae Branco and Menezes were newly described from Brazilian waters. In the ANCA region, HAEDAT listed 131 records from 1956 to 2018. The main problems are PSP and Ciguatera and common HAB taxa are Gambierdiscus, Gymnodinium, Pyrodinium, Alexandrium and Dinophysis. The most reported HAB forming species are Gymnodinium catenatum, Pyrodinium bahamense and Gambierdiscus spp. In recent years Margalefidinium polykrikoides blooms have become frequent, causing fish and invertebrates massive mortalities and impacts on touristic activities. In the LAC region, the greates
- Published
- 2021
209. Harmful algal blooms and their effects in coastal seas of Northern Europe
- Abstract
Harmful algal blooms (HAB) are recurrent phenomena in northern Europe along the coasts of the Baltic Sea, Kattegat-Skagerrak, eastern North Sea, Norwegian Sea and the Barents Sea. These HABs have caused occasional massive losses for the aquaculture industry and have chronically affected socioeconomic interests in several ways. This status review gives an overview of historical HAB events and summarises reports to the Harmful Algae Event Database from 1986 to the end of year 2019 and observations made in long term monitoring programmes of potentially harmful phytoplankton and of phycotoxins in bivalve shellfish. Major HAB taxa causing fish mortalities in the region include blooms of the prymnesiophyte Chrysochromulina leadbeateri in northern Norway in 1991 and 2019, resulting in huge economic losses for fish farmers. A bloom of the prymesiophyte Prymnesium polylepis (syn. Chrysochromulina polylepis) in the Kattegat-Skagerrak in 1988 was ecosystem disruptive. Blooms of the prymnesiophyte Phaeocystis spp. have caused accumulations of foam on beaches in the southwestern North Sea and Wadden Sea coasts and shellfish mortality has been linked to their occurrence. Mortality of shellfish linked to HAB events has been observed in estuarine waters associated with influx of water from the southern North Sea. The first bloom of the dictyochophyte genus Pseudochattonella was observed in 1998, and since then such blooms have been observed in high cell densities in spring causing fish mortalities some years. Dinoflagellates, primarily Dinophysis spp., intermittently yield concentrations of Diarrhetic Shellfish Toxins (DST) in blue mussels, Mytilus edulis, above regulatory limits along the coasts of Norway, Denmark and the Swedish west coast. On average, DST levels in shellfish have decreased along the Swedish and Norwegian Skagerrak coasts since approximately 2006, coinciding with a decrease in the cell abundance of D. acuta. Among dinoflagellates, Alexandrium species are the m
- Published
- 2021
210. Impacts of ocean acidification on growth and toxin content of the marine diatoms Pseudo-nitzschia australis and P. fraudulenta
- Abstract
This paper present the effects of ocean acidification on growth and domoic acid (DA) content of several strains of the toxic Pseudo-nitzschia australis and the non-toxic P. fraudulenta. Three strains of each species (plus two subclones of P. australis) were acclimated and grown in semi-continuous cultures at three pH levels: 8.07, 7.77, and 7.40, in order to simulate changes of seawater pH from present to plausible future levels. Our results showed that lowering pH from current level (8.07) to predicted pH level in 2100 (7.77) did not affect the mean growth rates of some of the P. australis strains (FR-PAU-17 and L3-100), but affected other strains either negatively (L3-30) or positively (L3.4). However, the growth rates significantly decreased with pH lowered to 7.40 (by 13% for L3-100, 43% for L3-30 and 16% for IFR-PAU-17 compared to the rates at pH 8.07). In contrast, growth rates of the non-toxic P. fraudulenta strains were not affected by pH changing from 8.07 to 7.40. The P. australis strains produced DA at all pH levels tested, and the highest particulate DA concentration normalized to cell abundance (pDA) was found at pH 8.07. Total DA content (pDA and dissolved DA) was significantly higher at current pH (8.07) compared to pH (7.77), exept for one strain (L 3.4) where no difference was found. At lower pH levels 7.77–7.40, total DA content was similar, except for strains IFR-PAU-17 and L3-100 which had the lowest content at the pH 7.77. The diversity in the responses in growth and DA content highlights the inter- and intra-specific variation in Pseudo-nitzschia species in response to ocean acidification. When exploring environmental responses of Pseudo-nitzschia using cultured cells, not only strain-specific variation but also culturing history should be taken into consideration, as the light levels under which the subclones were cultured, afterwards affected both maximum growth rates and DA content.
- Published
- 2021
211. Harmful algal blooms and their effects in coastal seas of Northern Europe
- Abstract
Harmful algal blooms (HAB) are recurrent phenomena in northern Europe along the coasts of the Baltic Sea, Kattegat-Skagerrak, eastern North Sea, Norwegian Sea and the Barents Sea. These HABs have caused occasional massive losses for the aquaculture industry and have chronically affected socioeconomic interests in several ways. This status review gives an overview of historical HAB events and summarises reports to the Harmful Algae Event Database from 1986 to the end of year 2019 and observations made in long term monitoring programmes of potentially harmful phytoplankton and of phycotoxins in bivalve shellfish. Major HAB taxa causing fish mortalities in the region include blooms of the prymnesiophyte Chrysochromulina leadbeateri in northern Norway in 1991 and 2019, resulting in huge economic losses for fish farmers. A bloom of the prymesiophyte Prymnesium polylepis (syn. Chrysochromulina polylepis) in the Kattegat-Skagerrak in 1988 was ecosystem disruptive. Blooms of the prymnesiophyte Phaeocystis spp. have caused accumulations of foam on beaches in the southwestern North Sea and Wadden Sea coasts and shellfish mortality has been linked to their occurrence. Mortality of shellfish linked to HAB events has been observed in estuarine waters associated with influx of water from the southern North Sea. The first bloom of the dictyochophyte genus Pseudochattonella was observed in 1998, and since then such blooms have been observed in high cell densities in spring causing fish mortalities some years. Dinoflagellates, primarily Dinophysis spp., intermittently yield concentrations of Diarrhetic Shellfish Toxins (DST) in blue mussels, Mytilus edulis, above regulatory limits along the coasts of Norway, Denmark and the Swedish west coast. On average, DST levels in shellfish have decreased along the Swedish and Norwegian Skagerrak coasts since approximately 2006, coinciding with a decrease in the cell abundance of D. acuta. Among dinoflagellates, Alexandrium species are the m
- Published
- 2021
212. Harmful algal blooms and their effects in coastal seas of Northern Europe
- Abstract
Harmful algal blooms (HAB) are recurrent phenomena in northern Europe along the coasts of the Baltic Sea, Kattegat-Skagerrak, eastern North Sea, Norwegian Sea and the Barents Sea. These HABs have caused occasional massive losses for the aquaculture industry and have chronically affected socioeconomic interests in several ways. This status review gives an overview of historical HAB events and summarises reports to the Harmful Algae Event Database from 1986 to the end of year 2019 and observations made in long term monitoring programmes of potentially harmful phytoplankton and of phycotoxins in bivalve shellfish. Major HAB taxa causing fish mortalities in the region include blooms of the prymnesiophyte Chrysochromulina leadbeateri in northern Norway in 1991 and 2019, resulting in huge economic losses for fish farmers. A bloom of the prymesiophyte Prymnesium polylepis (syn. Chrysochromulina polylepis) in the Kattegat-Skagerrak in 1988 was ecosystem disruptive. Blooms of the prymnesiophyte Phaeocystis spp. have caused accumulations of foam on beaches in the southwestern North Sea and Wadden Sea coasts and shellfish mortality has been linked to their occurrence. Mortality of shellfish linked to HAB events has been observed in estuarine waters associated with influx of water from the southern North Sea. The first bloom of the dictyochophyte genus Pseudochattonella was observed in 1998, and since then such blooms have been observed in high cell densities in spring causing fish mortalities some years. Dinoflagellates, primarily Dinophysis spp., intermittently yield concentrations of Diarrhetic Shellfish Toxins (DST) in blue mussels, Mytilus edulis, above regulatory limits along the coasts of Norway, Denmark and the Swedish west coast. On average, DST levels in shellfish have decreased along the Swedish and Norwegian Skagerrak coasts since approximately 2006, coinciding with a decrease in the cell abundance of D. acuta. Among dinoflagellates, Alexandrium species are the majo
- Published
- 2021
213. Elucidation of the Algicidal Mechanism of the Marine Bacterium Pseudoruegeria sp. M32A2M Against the Harmful Alga Alexandrium catenella Based on Time-Course Transcriptome Analysis
- Author
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Byung-Kwan Cho, Hee-Mock Oh, Chi-Yong Ahn, Sangrak Jin, Sang-Hyeok Cho, Bo-Seong Jeong, Eunju Lee, Yujin Jeong, Byung-Ha Oh, So-Ra Ko, and Suhyung Cho
- Subjects
Alexandrium catenella ,Science ,algicidal bacteria ,Alexandrium ,Ocean Engineering ,Oxidative phosphorylation ,QH1-199.5 ,Aquatic Science ,Oceanography ,Transcriptome ,medicine ,harmful algae ,Paralytic shellfish poisoning ,Water Science and Technology ,Global and Planetary Change ,biology ,Chemistry ,Dinoflagellate ,General. Including nature conservation, geographical distribution ,biology.organism_classification ,medicine.disease ,symbiosis ,Citric acid cycle ,Metabolic pathway ,Biochemistry ,transcriptome ,Bacteria - Abstract
The marine dinoflagellate Alexandrium is associated with harmful algal blooms (HABs) worldwide, causing paralytic shellfish poisoning (PSP) in humans. We found that the marine bacterium Pseudoruegeria sp. M32A2M exhibits algicidal activity against Alexandrium catenella (Group I), inhibiting its motility and consequently inducing cell disruption after 24 h of co-culture. To understand the communication between the two organisms, we investigated the time-course cellular responses through genome-wide transcriptome analysis. Functional analysis of differentially expressed genes revealed that the core reactions of the photosystem in A. catenella were inhibited within 2 h, eventually downregulating the entire pathways of oxidative phosphorylation and carbon fixation, as well as associated metabolic pathways. Conversely, Pseudoruegeria upregulated its glycolysis, tricarboxylic acid cycle, and oxidative phosphorylation pathways. Also, the transporters for nutrients such as C3/C4 carbohydrates and peptides were highly upregulated, leading to the speculation that nutrients released by disrupted A. catenella cells affect the central metabolism of Pseudoruegeria. In addition, we analyzed the secondary metabolite-synthesizing clusters of Pseudoruegeria that were upregulated by co-culture, suggesting their potential roles in algicidal activity. Our time-course transcriptome analysis elucidates how A. catenella is affected by algicidal bacteria and how these bacteria obtain functional benefits through metabolic pathways.
- Published
- 2021
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214. Detection of the Benthic Dinoflagellates, Ostreopsis cf. ovata and Amphidinium massartii (Dinophyceae), Using Loop-Mediated Isothermal Amplification
- Author
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Jun-Ho Hyung, Jinik Hwang, Jae Yeon Park, and Eun Sun Lee
- Subjects
Detection limit ,In situ ,Chromatography ,biology ,Amphidinium ,Chemistry ,Naval architecture. Shipbuilding. Marine engineering ,Loop-mediated isothermal amplification ,Dinoflagellate ,VM1-989 ,Ocean Engineering ,GC1-1581 ,biology.organism_classification ,Oceanography ,molecular detection ,monitoring ,Real-time polymerase chain reaction ,Benthic zone ,harmful algae ,Jeju coastal waters ,Water Science and Technology ,Civil and Structural Engineering ,Dinophyceae - Abstract
For the in situ and sensitive detection of benthic dinoflagellates, we have established an integrated loop-mediated isothermal amplification (LAMP) assay based on Ostreopsis cf. ovata and Amphidinium massartii. To detect the two species, a set of species-specific primers was constructed between the ITS gene and D1–D6 LSU gene, and the reaction temperature, time, and buffer composition were optimized to establish this method. In addition, the specificity of the LAMP primers was verified both in strains established in the laboratory and in field samples collected from the Jeju coastal waters, Korea. With the LAMP assay, the analysing time was within 45 to 60 min, which may be shorter than that with the conventional PCR. The detection sensitivity of the LAMP assay for O. cf. ovata or A. massartii was comparable to other molecular assays (PCR and quantitative PCR (qPCR)) and microscopy examination. The detection limit of LAMP was 0.1 cell of O. cf. ovata and 1 cell of A. massartii. The optimized LAMP assay was successfully applied to detect O. cf. ovata and A. massartii in field samples. Thus, this study provides an effective method for detecting target benthic dinoflagellate species, and could be further implemented to monitor phytoplankton in field surveys as an altenative.
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- 2021
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215. Impacts of ocean acidification on growth and toxin content of the marine diatoms Pseudo-nitzschia australis and P. fraudulenta
- Author
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Fabienne Hervé, Nour Ayache, Nina Lundholm, Amandine M.N. Caruana, Frederik Frøsig Gai, and Zouher Amzil
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0106 biological sciences ,Oceans and Seas ,Aquatic Science ,Oceanography ,medicine.disease_cause ,010603 evolutionary biology ,01 natural sciences ,Domoic acid ,chemistry.chemical_compound ,Animal science ,Amnesic shellfish poisoning ,medicine ,Harmful algae ,Seawater ,Diatoms ,Kainic Acid ,Ph level ,biology ,Strain (chemistry) ,Toxin ,010604 marine biology & hydrobiology ,Ocean acidification ,General Medicine ,Hydrogen-Ion Concentration ,biology.organism_classification ,Pollution ,chemistry ,Pseudo-nitzschia ,Marine Toxins - Abstract
This paper present the effects of ocean acidification on growth and domoic acid (DA) content of several strains of the toxic Pseudo-nitzschia australis and the non-toxic P. fraudulenta. Three strains of each species (plus two subclones of P. australis) were acclimated and grown in semi-continuous cultures at three pH levels: 8.07, 7.77, and 7.40, in order to simulate changes of seawater pH from present to plausible future levels. Our results showed that lowering pH from current level (8.07) to predicted pH level in 2100 (7.77) did not affect the mean growth rates of some of the P. australis strains (FR-PAU-17 and L3-100), but affected other strains either negatively (L3-30) or positively (L3.4). However, the growth rates significantly decreased with pH lowered to 7.40 (by 13% for L3-100, 43% for L3-30 and 16% for IFR-PAU-17 compared to the rates at pH 8.07). In contrast, growth rates of the non-toxic P. fraudulenta strains were not affected by pH changing from 8.07 to 7.40. The P. australis strains produced DA at all pH levels tested, and the highest particulate DA concentration normalized to cell abundance (pDA) was found at pH 8.07. Total DA content (pDA and dissolved DA) was significantly higher at current pH (8.07) compared to pH (7.77), exept for one strain (L 3.4) where no difference was found. At lower pH levels 7.77–7.40, total DA content was similar, except for strains IFR-PAU-17 and L3-100 which had the lowest content at the pH 7.77. The diversity in the responses in growth and DA content highlights the inter- and intra-specific variation in Pseudo-nitzschia species in response to ocean acidification. When exploring environmental responses of Pseudo-nitzschia using cultured cells, not only strain-specific variation but also culturing history should be taken into consideration, as the light levels under which the subclones were cultured, afterwards affected both maximum growth rates and DA content.
- Published
- 2021
216. Acclimation traits determine the macromolecular basis of harmful dinoflagellate Alexandrium minutum in response to changing climate conditions.
- Author
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Thangaraj, Satheeswaran, Liu, Haijiao, Kim, Il-Nam, and Sun, Jun
- Subjects
- *
ACCLIMATIZATION , *CLIMATE change , *ALEXANDRIUM , *OCEAN acidification , *CARBON dioxide , *CELL physiology - Abstract
• Combined temperature and p CO 2 elevation, were investigated at a different transitional period of A. minutum for its acclimation. • This is the first study to consider depicting conditions of ocean warming and acidification on the element storage and related functional processes modification in A. minutum. • Combined temperature and p CO 2 elevation induced luxurious nitrogen and phosphate contents during the acclimation process. • Both nitrogen and phosphate molecules have unique functions to promote efficient growth and proliferation of A. minutum in the future ocean conditions. Ocean warming and acidification are expected to have profound impacts on the marine ecosystem, although the dinoflagellate Alexandrium minutum is reported to be acclimated to such conditions. However, it is unknown on the transition time scale how this species physiologically adjusts their element accumulation and associated resource allocation for this process. We designed a set of experiments to examine how different culture generations (1st, 5th, and 10th) change their cell physiology, cellular quotas and macromolecular cellular contents related to functional processes in A. minutum grown with future (p CO 2 , 1000 ppm; 25°C) and present (p CO 2 , 400 ppm; 21°C) ocean conditions. The differing cell sizes and storage capacity at different generations confirmed that compared to ancestors (1st generation), acclimation cells (10th generation) gained increases in quota carbon (Q C ; 55%; [ p < 0.05]) and quota phosphate (Q P ; 23% [ p < 0.05]). This variation in C:P and N:P influences was transition-specific and largely determined by phosphate-based molecules. It was observed that A. minutum was initially dependent on P molecules, which help cells act as alternative lipids for quick acclimation until N molecules resume carbon-based lipids for their long-term acclimation. Our study demonstrated that rising temperature and p CO 2 concentrations in ocean may increase A. minutum based on the comprehensive analysis of different physiological modifications, including its growth, element accumulation, transformation, and functional allocation. [ABSTRACT FROM AUTHOR]
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- 2022
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217. Toxic dinoflagellates (Dinoflagellata) the coast of Chiapas , Mexico , Eastern Pacific center
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Ebodio Maciel-Baltazar
- Subjects
Dinoflagellates ,red tide ,harmful algae ,ficotoxins ,Chiapas ,General Works - Abstract
In this paper are given to know toxic species with public health importance, samples were obtained during 2010-2012 in the coast of Chiapas, México, by net (20 μm mesh) in vertical hauls (up to 15 m), fixed with Lugol’s solution and studied by light microscope bright field, Twenty-four species were documented to be present in the study área: Gymnodinium (1); Alexandrium (5); Pyrodinium (1); Phalacroma (2); Dinophysis (4);Prorocentrum (4); Karenia (4); Protoceratium (1); Gonyaulax (1); Lingulodinium (1), It was found corresponding with 64-89% of the species from coastal waters of México.
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- 2015
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218. Gene expression in the mixotrophic prymnesiophyte, Prymnesium parvum, responds to prey availability
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Zhenfeng eLiu, Adriane C Jones, Victoria eCampbell, K. David eHambright, Karla B Heidelberg, and David A Caron
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Gene Expression ,Transcriptomics ,harmful algae ,Prymnesium parvum ,Mixotrophic Protist ,Golden Alage ,Microbiology ,QR1-502 - Abstract
The mixotrophic prymnesiophyte, Prymnesium parvum, is a widely distributed alga with significant ecological importance. It produces toxins and can form ecosystem disruptive blooms that result in fish kills and changes in planktonic food web structure. However, the relationship between P. parvum and its prey on the molecular level is poorly understood. In this study, we used RNA-Seq technology to study changes in gene transcription of P. parvum in three treatments with different microbial populations available as potential prey: axenic P. parvum (no prey), bacterized P. paruvm, and axenic P. parvum with ciliates added as prey. Thousands of genes were differentially expressed among the three treatments. Most notably, transcriptome data indicated that P. parvum obtained organic carbon, including fatty acids, from both bacteria and ciliate prey for energy and cellular building blocks. The data also suggested that different prey provided P. parvum with macro- and micronutrients, namely organic nitrogen in the form of amino acids from ciliates, and iron from bacteria. However, both transcriptomic data and growth experiments indicated that P. parvum did not grow faster in the presence of prey despite the gains in nutrients, although algal abundances attained in culture were slightly greater in the presence of prey. The relationship between phototrophy, heterotrophy and growth of P. parvum is discussed.
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- 2015
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219. Harmful algae and toxis in paranaguá bay , Brazil: bases for monitoring
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Luiz Laureno Mafra Junior, Luciano Felício Fernandes, and Luís Antonio O. Proença
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Fitoplâncton ,Algas Nocivas ,Monitoramento ,Toxinas ,Mytella guyanensis ,Paranaguá ,Sul do Brasil ,Phytoplankton ,Harmful Algae ,Monitoring ,Toxins ,South Brazil ,Oceanography ,GC1-1581 - Abstract
The estuarine complex of Paranaguá - ECP (South Brazil, 25º30'S, 48º30'W) is a large subtropical system, where pristine mangrove forests are still present, and fishery and aquaculture are important economic activities. This work investigated the occurrence of harmful algae in Paranaguá Bay, as well as the presence of toxins in the filter feeding mussel Mytella guyanensis, a local fishery resource. Samples along the Paranaguá sub-system were collected almost monthly from August 2002 to October 2003. Besides physical and chemical variables, cell densities of harmful species and presence of toxins in the mussel by mouse bioassay (DSP, PSP) and HPLC (ASP) were performed. HAB species included Pseudo-nitzschia spp., Dinophysis acuminata,Prorocentrum minimum,Gymnodinium catenatum,Phaeocystis spp., Chattonella spp. and Heterosigma akashiwo.Trichodesmium erythraeum and Coscinodiscus wailesii were also included in this study due to their potential for harmful bloom formation. Toxin results showed the occurrence of DSP (December 2002) in shellfish related to the presence of D. acuminata (max. 4,566 cells.l-1). Additionally, cultivated strains produced paralytic and amnesic toxins in laboratory. Spring (October to December, Southern Hemisphere) and late summer (February to April) were the periods of higher abundance of harmful algae, mainly in euhaline and inner polyhaline sectors of the ECP.O complexo estuarino de Paranaguá (CEP; 25º30'S, 48º30'W), localizado no litoral sul do Brasil, abriga extensas áreas preservadas de manguezais e tem a pesca e aqüicultura como importantes atividades econômicas. Este trabalho investigou a ocorrência de microalgas nocivas no CEP e a presença de ficotoxinas no molusco bivalve Mytella guyanensis. Para tanto, foram coletadas amostras com periodicidade aproximadamente mensal, entre agosto de 2002 e outubro de 2003. Foram avaliadas variáveis físico-químicas, densidade de espécies nocivas e a presença de toxinas nos moluscos através de bioensaio com camundongos (DSP e PSP) e por cromatografia líquida (ASP). As espécies nocivas encontradas foram Pseudo-nitzschia spp., Dinophysis acuminata,Prorocentrum minimum,Gymnodinium catenatum,Phaeocystis spp., Chattonella spp. e Heterosigma akashiwo. Além dessas, Trichodesmium erythraeum e Coscinodiscus wailesii foram também incluídas no estudo pelo potencial de produzirem eventos nocivos na região. Toxinas diarréicas (DSP) foram detectadas em moluscos em dezembro de 2002 associadas à presença de D. acuminata (até 4.566 cel.l-1). Toxinas paralisantes e amnésicas foram produzidas por cepas cultivadas em laboratório. Primavera (de outubro a dezembro no hemisfério Sul) e final do verão (fevereiro a abril) foram os períodos de maior abundância de algas nocivas principalmente nos setores euhalino e polihalino interno do CEP.
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- 2006
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220. Dynamics of phytoplankton communities in eutrophying tropical shrimp ponds affected by vibriosis.
- Author
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Lemonnier, Hugues, Lantoine, François, Courties, Claude, Guillebault, Delphine, Nézan, Elizabeth, Chomérat, Nicolas, Escoubeyrou, Karine, Galinié, Christian, Blockmans, Bernard, and Laugier, Thierry
- Subjects
PHYTOPLANKTON ,VIBRIOSIS in fishes ,FISH mortality ,AQUACULTURE ,BACTERIA phylogeny ,DISEASE susceptibility ,FLOW cytometry - Abstract
Tropical shrimp aquaculture systems in New Caledonia regularly face major crises resulting from outbreaks of Vibrio infections. Ponds are highly dynamic and challenging environments and display a wide range of trophic conditions. In farms affected by vibriosis, phytoplankton biomass and composition are highly variable. These conditions may promote the development of harmful algae increasing shrimp susceptibility to bacterial infections. Phytoplankton compartment before and during mortality outbreaks was monitored at a shrimp farm that has been regularly and highly impacted by these diseases. Combining information from flow cytometry, microscopy, pigment and phylogenetic analysis, the presence of Picocyanobacteria, Prasinophyceae and Diatomophyceae were detected as dominant phytoplankton groups and Cryptophyceae, Prymnesiophyceae and Dinophyceae as minor components. At the onset of the first shrimp mortalities, Bacillariophyceae increased while Cyanobacteria, Prymnesiophyceae and Dinophyceae decreased in the water column, followed by proliferation of Prasinophyceae. Several taxa were identified as potential harmful algae (Cyanobacteria, dinoflagellates and Phaeocystis ). [ABSTRACT FROM AUTHOR]
- Published
- 2016
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221. Quaternized chitosan-intercalated montmorillonite composite for cyanobacterial bloom inhibition.
- Author
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Na Gu, Jinlong Gao, Kuitao Wang, Yuan Zhao, Heng Li, and Yulin Ma
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MONTMORILLONITE ,CYANOBACTERIAL blooms ,FOURIER transform infrared spectroscopy ,TRANSMISSION electron microscopy - Abstract
A composite based on quaternized chitosan and montmorillonite was developed as an environment-friendly algaecide for emergency management of harmful algae bloom. The composites were prepared via the ultrasonic intercalation solution method. X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), differential scanning calorimetry- thermogravimetry analysis (DSG/TG) and high-resolution transmission electron microscopy (HRTEM) were used to characterize the composite. The quaternized chitosan was intercalated into the interlayer of montmorillonite, leading to a greater disorder degree of montmorillonite lamella, and the mass fraction of intercalation was approximately 20.6%. Quaternized chitosan intercalated montmorillonite effectively removed Oscillatoria by the deposition netting and electrostatic neutralization mechanism and cleared up the cyanobacterial bloom in natural landscape water body within 48 h. Quaternized chitosan, the effective algicide in the interlayer of montmorillonite, released slowly, inhibited the activity of Oscillatoria in the long term, and effectively prevented the resuspension of algae aggregates. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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222. Harmful Algal in Banyuasin Coastal Waters, South Sumatera.
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Aryawati, Riris, Bengen, Dietriech Geoffrey, Tri Prartono, and Zulkifli, Hilda
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- *
PHYTOPLANKTON , *FOOD chains , *TERRITORIAL waters - Abstract
Phytoplankton have important as food-chain major component and primary production of marine environment. However, high abundance of phytoplankton could give harmful effects toward water ecosystem. Moreover, they could produce toxic substances that will be accumulated within their consumer. This accumulation could be dangerous for human or animals. This research were aimed to determine and calculatespecies of harmful algae in Banyuasin coastal waters. The study was conducted on April, June, August, October and December of 2013, and in February 2014, at ten stations. Phytoplankton samples were taken vertically using plankton nets. In the form of cone-shaped with a diameter of 30 cm, length 100 cm and mesh size 30 µm. The result showed that there are 35 genera of phytoplankton. That have been found and consisted of four groups; Bacillariophyceae, Dinophyceae, Cyanophyceae and Chlorophyceae. 13 species were identified as Harmful Algal (Chaetoceros, Coscinodiscus, Nitzschia, Skeletonema, Thalassiosira, Alexandrium, Ceratium, Dinophysis, Noctiluca, Protoperidinium, Prorocentrum, Anabaena dan Oscillatoria), with seven of them were known for having toxin (Nitzschia, Alexandrium, Dinophysis, Protoperidinium Prorocentrum, Anabaena and Oscillatoria). Monitoring result showed that the highest number of species of potential harmful algal blooms (HABs) occured in June and the highest abundance occured in August, especially Chaetoceros and Skeletonema. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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223. Effects of nitrogen supply on Pseudo- nitzschia calliantha and Pseudo- nitzschia cf . seriata: field and laboratory experiments.
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Melliti Ben Garali, Sondes, Sahraoui, Inès, de la Iglesia, Pablo, Chalghaf, Mohamed, Diogène, Jorge, Ksouri, Jamel, and Sakka Hlaili, Asma
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NITZSCHIA ,DIATOMS ,NITROGEN ,DOMOIC acid ,SEAWATER - Abstract
The effects of inorganic and organic nitrogen supply on the growth and domoic acid (DA) production of Pseudo- nitzschia cf. seriata and Pseudo- nitzschia calliantha from Bizerte Lagoon (SW Mediterranean Sea) were studied during field and laboratory experiments. Nitrogen enrichments (40 µM NO; 10 µM NH; 20 µM CHNO) and a control, with no added N, were carried out in separate carboys with seawater collected from Bizerte Lagoon. In the field experiments, all N-enrichments resulted in significant increases in chlorophyll a concentration, and maintained exponential growth until the end of the experiment. The initial diatom community was dominated by a bloom of P. cf. seriata (9.3 × 10 cells l). After 6 days of incubation, the abundance of P. cf. seriata was greatest in the urea addition (1.52 × 10 cells l), compared to the ammonium treatment (0.47 × 10 cells l), nitrate treatment (0.70 × 10 cells l) and control (0.36 × 10 cells l). The specific growth rates, calculated from increases in chlorophyll a and cell abundance, were statistically different across all treatments, with the highest in the urea and nitrate additions. Similar results were obtained from the laboratory experiments. These were carried out with P. calliantha isolated from Bizerte Lagoon and grown in f/2 medium enriched with 40 µM nitrate, 10 µM ammonium and 20 µM urea. The exponential growth rate was significantly faster for the cells cultured with urea (1.50 d) compared to the nitrate (0.90 d) and ammonium (0.80 d) treatments and the control (0.40 d). Analysis of DA, performed at the beginning and the end of the both experiments in all treatments, revealed very low concentrations (below the limit of quantification, 0.02- 1.310 pg cell, respectively).The field and laboratory experiments demonstrate that P.cf. seriata and P. calliantha are able to grow efficiently on the three forms of N, but with a preference for urea. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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224. The association between razor clam consumption and memory in the CoASTAL cohort.
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Grattan, Lynn M., Boushey, Carol, Tracy, Kate, Trainer, Vera L., Roberts, Sparkle M., Schluterman, Nicolas, and Jr.Morris, J. Glenn
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- *
RAZOR clams , *DOMOIC acid , *COHORT analysis , *ACQUISITION of data , *GENERALIZED estimating equations - Abstract
This study represents a preliminary effort to examine the potential impacts of chronic, low level domoic acid (DA) exposure on memory in the CoASTAL cohort over the first four years of data collection (Wave 1). Five hundred and thirteen adult men and women representing three Native American Tribes were studied annually with standard measures of cognition and razor clam consumption (a known vector of DA exposure) over a four-year period. In addition, a pilot metric of DA concentration exposure was used which took into consideration average DA concentration levels in source beaches, as well as the amount consumed. Based upon generalized estimating equations (GEE) analysis, controlling for age, sex, race, year, education level, tribe, and employment status, findings indicated that high razor clam consumers (15 or more per month) had isolated decrements on some measures of memory ( p = 0.02–0.03), with other cognitive functions unaffected. The relatively lower memory scores were still within normal limits, and were thus not clinically significant. The pilot DA exposure metric had no association with any other aspect of cognition or behavior. There is a possible association between long-term, low-level exposure to DA through heavy razor clam consumption and memory functioning. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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225. Phytoplankton dynamics in the Southern California Bight indicate a complex mixture of transport and biology.
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BIALONSKI, STEPHAN, CARON, DAVID A., SCHLOEN, JULIA, FEUDEL, ULRIKE, KANTZ, HOLGER, and MOORTHI, STEFANIE D.
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- *
GEOGRAPHICAL distribution of phytoplankton , *ALGAL blooms , *BAYS , *HYDROGRAPHY , *OCEAN currents , *CROSS correlation , *SIMULATION methods & models , *LAGRANGIAN mechanics - Abstract
The stimulation and dominance of potentially harmful phytoplankton taxa at a given locale and time are determined by local environmental conditions as well as by transport to or from neighboring regions. The present study investigated the occurrence of common harmful algal bloom (HAB) taxa within the Southern California Bight, using cross-correlation functions to determine potential dependencies between HAB taxa and environmental factors, and potential links to algal transport via local hydrography and currents. A simulation study, in which Lagrangian particles were released, was used to assess travel times due to advection by prevailing ocean currents in the bight. Our results indicate that transport of some taxa may be an important mechanism for the expansion of their distributions into other regions, which was supported by mean travel times derived from our simulation study and other literature on ocean currents in the Southern California Bight. In other cases, however, phytoplankton dynamics were rather linked to local environmental conditions, including coastal upwelling events. Overall, our study shows that complex current patterns in the Southern California Bight may contribute significantly to the formation and expansion of HABs in addition to local environmental factors determining the spatiotemporal dynamics of phytoplankton blooms. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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226. Variability of Winter-Spring Bloom Phaeocystis pouchetii Abundance in Massachusetts Bay.
- Author
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Borkman, David, Libby, P., Mickelson, Michael, Turner, Jefferson, and Jiang, Mingshun
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ALGAE ,BIODIVERSITY ,PRYMNESIOPHYCEAE ,MICROSCOPY ,PHYTOPLANKTON - Abstract
Abundance of the prymnesiophyte Phaeocystis pouchetii was quantified via light microscopy at 2-week to monthly intervals in Massachusetts Bay (southern Gulf of Maine, NW Atlantic) during 1992-2012. Variability in the abundance and seasonal cycle of Phaeocystis are described and synoptic hydrographic, nutrient, and meteorological data were analyzed to identify factors that may influence Phaeocystis abundance. The maximum Phaeocystis abundance was 14 × 10 cells L (10 Apr 2008). It was frequently (5 of 8 years) absent prior to year 2000, but not thereafter. Seasonally, it first appeared in February to early March, reached peak abundance in mid-April, and persisted until May or early June for a duration of 0-112 days (mean 34 days). A long-term alternation between Phaeocystis and centric diatom abundance was apparent, suggesting winter-spring selection of either Phaeocystis or centric diatoms. Phytoplankton community analysis suggested that blooms affected the rest of the phytoplankton community. Phaeocystis blooms were manifest as a substantial increase in particulate nutrients above normal levels. Phaeocystis blooms were preceded in February by a slightly elevated concentration of NO (9.3 vs. 6.5 μM when absent) and PO (0.99 vs. 0.79 μM when absent). Blooms were also preceded by elevated ratios of NO/PO, NO/Si, and PO/Si, and warmer, saltier waters reflecting reduced river discharge. The correlation with salinity and river discharge suggests that Phaeocystis bloom variability is partially determined by annually varying circulation processes that determine the degree of low nutrient, low salinity coastal water intrusion into Massachusetts Bay. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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227. Transcriptome Analysis of Scrippsiella trochoidea CCMP 3099 Reveals Physiological Changes Related to Nitrate Depletion.
- Author
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Cooper, Joshua T., Sinclair, Geoffrey A., Wawrik, Boris, Van De Waal, Dedmer Bareld, and Senjie Lin
- Subjects
DINOFLAGELLATES ,ALGAL blooms ,BIOCHEMISTRY ,PHYSIOLOGY - Abstract
Dinoflagellates are a major component of marine phytoplankton and many species are recognized for their ability to produce harmful algal blooms (HABs). Scrippsiella trochoidea is a non-toxic, marine dinoflagellate that can be found in both cold and tropic waters where it is known to produce "red tide" events. Little is known about the genomic makeup of S. trochoidea and a transcriptome study was conducted to shed light on the biochemical and physiological adaptations related to nutrient depletion. Cultures were grown under N and P limiting conditions and transcriptomes were generated via RNAseq technology. De novo assembly reconstructed 107,415 putative transcripts of which only 41% could be annotated. No significant transcriptomic response was observed in response to initial P depletion, however, a strong transcriptional response to N depletion was detected. Among the down-regulated pathways were those for glutamine/glutamate metabolism as well as urea and nitrate/nitrite transporters. Transcripts for ammonia transporters displayed both up- and down-regulation, perhaps related to a shift to higher affinity transporters. Genes for the utilization of DON compounds were up-regulated. These included transcripts for amino acids transporters, polyamine oxidase, and extracellular proteinase and peptidases. N depletion also triggered down regulation of transcripts related to the production of Photosystems I & II and related proteins. These data are consistent with a metabolic strategy that conserves N while maximizing sustained metabolism by emphasizing the relative contribution of organic N sources. Surprisingly, the transcriptome also contained transcripts potentially related to secondary metabolite production, including a homolog to the Short Isoform Saxitoxin gene (sxtA) from Alexandrium fundyense, which was significantly up-regulated under N-depletion. A total of 113 unique hits to Sxt genes, covering 17 of the 34 genes found in C. raciborskii were detected, indicating that S. trochoidea has previously unrecognized potential for the production of secondary metabolites with potential toxicity. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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228. Seasonality and toxin production of Pyrodinium bahamense in a Red Sea lagoon.
- Author
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Banguera-Hinestroza, E., Eikrem, W., Mansour, H., Solberg, I., Cúrdia, J., Holtermann, K., Edvardsen, B., and Kaartvedt, S.
- Subjects
- *
PYRODINIUM bahamense , *DINOFLAGELLATE blooms , *ALGAL toxins , *SEASONAL temperature variations , *ENZYME-linked immunosorbent assay - Abstract
Harmful algal blooms of the dinoflagellate Pyrodinium bahamense have caused human and economic losses in the last decades. This study, for the first time, documents a bloom of P. bahamense in the Red Sea. The alga was recurrently present in a semi-enclosed lagoon throughout nearly 2 years of observations. The highest cell densities (10 4 –10 5 cells L −1 ) were recorded from September to beginning of December at temperatures and salinities of ∼26–32 °C and ∼41, respectively. The peak of the bloom was recorded mid-November, before a sharp decrease in cell numbers at the end of December. Minimum concentrations in summer were at ∼10 3 cells L −1 . A saxitoxin ELISA immunoassay of cultures and water samples confirmed the toxicity of the strain found in the Red Sea. Moreover, a gene expression analysis of the saxitoxin gene domain SxtA4 showed that transcript production peaked at the culmination of the bloom, suggesting a relation between transcript production, sudden cells increment-decline, and environmental factors. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
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229. Effects of temperature and salinity on the growth of Alexandrium (Dinophyceae) isolates from the Salish Sea.
- Author
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Bill, Brian D., Moore, Stephanie K., Hay, Levi R., Anderson, Donald M., Trainer, Vera L., and Cock, M.
- Subjects
- *
EFFECT of temperature on protozoa , *PROTOZOAN growth , *SHELLFISH toxins , *CLIMATE change , *GROWTH rate - Abstract
Toxin-producing blooms of dinoflagellates in the genus Alexandrium have plagued the inhabitants of the Salish Sea for centuries. Yet the environmental conditions that promote accelerated growth of this organism, a producer of paralytic shellfish toxins, is lacking. This study quantitatively determined the growth response of two Alexandrium isolates to a range of temperatures and salinities, factors that will strongly respond to future climate change scenarios. An empirical equation, derived from observed growth rates describing the temperature and salinity dependence of growth, was used to hindcast bloom risk. Hindcasting was achieved by comparing predicted growth rates, calculated from in situ temperature and salinity data from Quartermaster Harbor, with corresponding Alexandrium cell counts and shellfish toxin data. The greatest bloom risk, defined at μ >0.25 d−1, generally occurred from April through November annually; however, growth rates rarely fell below 0.10 d−1. Except for a few occasions, Alexandrium cells were only observed during the periods of highest bloom risk and paralytic shellfish toxins above the regulatory limit always fell within the periods of predicted bloom occurrence. While acknowledging that Alexandrium growth rates are affected by other abiotic and biotic factors, such as grazing pressure and nutrient availability, the use of this empirical growth function to predict higher risk time frames for blooms and toxic shellfish within the Salish Sea provides the groundwork for a more comprehensive biological model of Alexandrium bloom dynamics in the region and will enhance our ability to forecast blooms in the Salish Sea under future climate change scenarios. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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230. Transcriptomic profiling of Alexandrium fundyense during physical interaction with or exposure to chemical signals from the parasite Amoebophrya.
- Author
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Lu, Yameng, Wohlrab, Sylke, Groth, Marco, Glöckner, Gernot, Guillou, Laure, and John, Uwe
- Subjects
- *
ALEXANDRIUM , *MICROALGAE , *ALGAL blooms , *ALGAE culture , *RNA sequencing ,PARASITE physiology - Abstract
Toxic microalgae have their own pathogens, and understanding the way in which these microalgae respond to antagonistic attacks may provide information about their capacity to persist during harmful algal bloom events. Here, we compared the effects of the physical presence of the parasite Amoebophrya sp. and exposure to waterborne cues from cultures infected with this parasite, on gene expression by the toxic dinoflagellates, Alexandrium fundyense. Compared with control samples, a total of 14 882 Alexandrium genes were differentially expressed over the whole-parasite infection cycle at three different time points (0, 6 and 96 h). RNA sequencing analyses indicated that exposure to the parasite and parasitic waterborne cues produced significant changes in the expression levels of Alexandrium genes associated with specific metabolic pathways. The observed upregulation of genes associated with glycolysis, the tricarboxylic acid cycle, fatty acid β-oxidation, oxidative phosphorylation and photosynthesis suggests that parasite infection increases the energy demand of the host. The observed upregulation of genes correlated with signal transduction indicates that Alexandrium could be sensitized by parasite attacks. This response might prime the defence of the host, as indicated by the increased expression of several genes associated with defence and stress. Our findings provide a molecular overview of the response of a dinoflagellate to parasite infection. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
231. Development and evaluation of a DNA microarray assay for the simultaneous detection of nine harmful algal species in ship ballast and seaport waters.
- Author
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Chen, Xianfeng, Zhou, Qianjin, Duan, Weijun, Zhou, Chengxu, Duan, Lijun, Zhang, Huili, Sun, Aili, Yan, Xiaojun, and Chen, Jiong
- Subjects
- *
DNA microarrays , *MICROALGAE , *TOXIN analysis , *PHYTOPLANKTON , *DNA analysis - Abstract
Rapid, high-throughput and reliable methods are urgently required to accurately detect and monitor harmful algae, which are responsible for algal blooms, such as red and green tides. In this study, we successfully developed a multiplex PCR-based DNA microarray method capable of detecting nine harmful algal species simultaneously, namely Alexandrium tamarense, Gyrodinium instriatum, Heterosigma akashiwo, Karenia mikimotoi, Prorocentrum donghaiense, Prorocentrum minimum, Ulva compressa, Ulva ohnoi and Ulva prolifera. This method achieved a limit of detection (LOD) of 0.5 ng of genomic DNA (orders of magnitude of the deci-nanogram range) in the tested algae cultures. Altogether, 230 field samples from ship ballast waters and seaport waters were used to evaluate the DNA microarray. The clinical sensitivity and specificity of the DNA microarray assay in detecting field samples were 96.4% and 90.9%, respectively, relative to conventional morphological methods. This indicated that this high-throughput, automatic, and specific method is well suited for the detection of algae in water samples. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
232. Exposure to the Paralytic Shellfish Toxin Producer Alexandrium catenella Increases the Susceptibility of the Oyster Crassostrea gigas to Pathogenic Vibrios.
- Author
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Abi-Khalil, Celina, Lopez-Joven, Carmen, Abadie, Eric, Savar, Veronique, Amzil, Zouher, Laabir, Mohamed, and Rolland, Jean-Luc
- Subjects
- *
POISONOUS shellfish , *MARINE toxins , *SEAFOOD poisoning , *PATHOGENIC microorganisms , *ALGAL blooms , *PARALYTIC shellfish toxins - Abstract
The multifactorial etiology of massive Crassostrea gigas summer mortalities results from complex interactions between oysters, opportunistic pathogens and environmental factors. In a field survey conducted in 2014 in the Mediterranean Thau Lagoon (France), we evidenced that the development of the toxic dinoflagellate Alexandrium catenella, which produces paralytic shellfish toxins (PSTs), was concomitant with the accumulation of PSTs in oyster fresh and the occurrence of C. gigas mortalities. In order to investigate the possible role of toxic algae in this complex disease, we experimentally infected C. gigas oyster juveniles with Vibrio tasmaniensis strain LGP32, a strain associated with oyster summer mortalities, after oysters were exposed to Alexandrium catenella. Exposure of oysters to A. catenella significantly increased the susceptibility of oysters to V. tasmaniensis LGP32. On the contrary, exposure to the non-toxic dinoflagellate Alexandrium tamarense or to the haptophyte Tisochrysis lutea used as a foraging alga did not increase susceptibility to V. tasmaniensis LGP32. This study shows for the first time that A. catenella increases the susceptibility of Crassostrea gigas to pathogenic vibrios. Therefore, in addition to complex environmental factors explaining the mass mortalities of bivalve mollusks, feeding on neurotoxic dinoflagellates should now be considered as an environmental factor that potentially increases the severity of oyster mortality events. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
233. The toxic benthic dinoflagellates of the genus Ostreopsis in temperate areas: a review.
- Author
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Accoroni, Stefano and Totti, Cecilia
- Subjects
- *
DINOFLAGELLATES , *PALYTOXIN - Abstract
The genus Ostreopsis includes species largely distributed from tropical to temperate marine areas worldwide. Among the nine species of the genus, O. siamensis, O. mascarenensis, O. lenticularis and O. cf. ovata can produce toxins of the palytoxin group. In the last decade Ostreopsis cf. ovata and O. cf. siamensis originated intense blooms in all the rocky Mediterranean Sea coastal areas, typically during summer-late summer. The correct identification of Ostreopsis species in field samples is often problematic as Ostreopsis species are morphologically plastic and hardly discriminable under light microscopy and, therefore, molecular analyses are required. Ostreopsis blooms are often associated with noxious effects on health of both humans and benthic marine organisms mainly carried by aerosol and direct contact with seawater. Environmental factors have been shown to affect toxin content of Ostreopsis which generally produces more toxins per cell when growing under suboptimal conditions. O. cf. ovata is able to produce both temporary and resting cysts. In particular, the resting cysts are able to germinate in laboratory conditions for as long as 5 months after their formation at 25°C, but not at 21°C; the presence of a temperature threshold affecting cyst germination in the laboratory suggests that temperature represents a key factor for Ostreopsis cf. ovata bloom onset in natural environments as well. Several studies conducted to assess the role of abiotic factors (mainly hydrodynamics, water temperature and nutrients) on the bloom dynamics, revealed that the synergic effects of hydrodynamics, temperature and N:P ratios would lead the Ostreopsis blooms in temperate areas. Ostreopsis abundances showed a significant decrease with depth, likely related to light availability, although there are conflicting data about the relationship between light intensity and Ostreopsis growth in experimental conditions. The relationship between Ostreopsis blooms and salinity is not completely clear, complicated by the influence of high nutrient levels often associated to low salinity waters. Finally, Ostreopsis colonize a variety of substrata, although living substrata seems to allow lower concentration of epibionts than any other substrate, probably due to the production of some allelopathic compounds. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
234. Are Harmful Algal Blooms Becoming the Greatest Inland Water Quality Threat to Public Health and Aquatic Ecosystems?
- Author
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Brooks, Bryan W., Lazorchak, James M., Howard, Meredith D.A., Johnson, Mari‐Vaughn V., Morton, Steve L., Perkins, Dawn A.K., Reavie, Euan D., Scott, Geoffrey I., Smith, Stephanie A., and Steevens, Jeffery A.
- Subjects
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ALGAL blooms , *AQUATIC ecology , *WATER quality , *PUBLIC health , *FRESHWATER habitats , *ENVIRONMENTAL toxicology - Abstract
In this Focus article, the authors ask a seemingly simple question: Are harmful algal blooms (HABs) becoming the greatest inland water quality threat to public health and aquatic ecosystems? When HAB events require restrictions on fisheries, recreation, and drinking water uses of inland water bodies significant economic consequences result. Unfortunately, the magnitude, frequency, and duration of HABs in inland waters are poorly understood across spatiotemporal scales and differentially engaged among states, tribes, and territories. Harmful algal bloom impacts are not as predictable as those from conventional chemical contaminants, for which water quality assessment and management programs were primarily developed, because interactions among multiple natural and anthropogenic factors determine the likelihood and severity to which a HAB will occur in a specific water body. These forcing factors can also affect toxin production. Beyond site-specific water quality degradation caused directly by HABs, the presence of HAB toxins can negatively influence routine surface water quality monitoring, assessment, and management practices. Harmful algal blooms present significant challenges for achieving water quality protection and restoration goals when these toxins confound interpretation of monitoring results and environmental quality standards implementation efforts for other chemicals and stressors. Whether HABs presently represent the greatest threat to inland water quality is debatable, though in inland waters of developed countries they typically cause more severe acute impacts to environmental quality than conventional chemical contamination events. The authors identify several timely research needs. Environmental toxicology, environmental chemistry, and risk-assessment expertise must interface with ecologists, engineers, and public health practitioners to engage the complexities of HAB assessment and management, to address the forcing factors for HAB formation, and to reduce the threats posed to inland surface water quality. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
235. DYNAMICS OF HARMFUL ALGAE WITH SEASONAL TEMPERATURE VARIATIONS IN THE COVE-MAIN LAKE.
- Author
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FENG-BIN WANG, SZE-BI HSU, and WENDI WANG
- Subjects
LAKES ,SEASONAL temperature variations ,REPRODUCTION ,ALGAE ,COMPUTER simulation - Abstract
In this paper, we investigate two-vessel gradostat models describing the dynamics of harmful algae with seasonal temperature variations, in which one vessel represents a small cove connected to a larger lake. We first define the basic reproduction number for the model system, and then show that the trivial periodic state is globally asymptotically stable, and algae is washed out eventually if the basic reproduction number is less than unity, while there exists at least one positive periodic state and algal blooms occur when it is greater than unity. There are several types of productions for dissolved toxins, related to the algal growth rate, and nutrient limitation, respectively. For the system with a specific toxin production, the global attractivity of positive periodic steady-state solution can be established. Numerical simulations from the basic reproduction number show that the factor of seasonality plays an important role in the persistence of harmful algae. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
236. Variations in morphology, growth, and toxicity among strains of the Prorocentrum lima species complex isolated from Cuba and Brazil
- Author
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Moreira-González, Angel R., Fernandes, Luciano F., Uchida, Hajime, Uesugi, Aya, Suzuki, Toshiyuki, Chomérat, Nicolas, Bilien, Gwenaël, and Mafra, Jr, Luiz L.
- Published
- 2019
- Full Text
- View/download PDF
237. Differential Mortality of North Atlantic Bivalve Molluscs During Harmful Algal Blooms Caused by the Dinoflagellate, Cochlodinium (a.k.a. Margalefidinium) polykrikoides
- Author
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Griffith, Andrew W., Shumway, Sandra E., and Gobler, Christopher J.
- Published
- 2019
- Full Text
- View/download PDF
238. Antioxidant responses of triangle sail mussel Hyriopsis cumingii exposed to harmful algae Microcystis aeruginosa and hypoxia.
- Author
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Hu, Menghong, Wu, Fangli, Yuan, Mingzhe, Li, Qiongzhen, Gu, Yedan, Wang, Youji, and Liu, Qigen
- Subjects
- *
ANTIOXIDANTS , *MICROCYSTIS aeruginosa , *HYPOXEMIA , *ALGAE , *SUPEROXIDE dismutase - Abstract
Bloom forming algae and hypoxia are considered to be two main co-occurred stressors associated with eutrophication. The aim of this study was to evaluate the interactive effects of harmful algae Microcystis aeruginosa and hypoxia on an ecologically important mussel species inhabiting lakes and reservoirs, the triangle sail mussel Hyriopsis cumingii , which is generally considered as a bio-management tool for eutrophication. A set of antioxidant enzymes involved in immune defence mechanisms and detoxification processes, i.e. glutathione-S-transferases (GST), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), lysozyme (LZM) in mussel haemolymph were analyzed during 14 days exposure along with 7 days depuration duration period. GST, GSH, SOD, GPX and LZM were elevated by toxic M. aeruginosa exposure, while CAT activities were inhibited by such exposure. Hypoxia influenced the immune mechanisms through the activation of GSH and GPX, and the inhibition of SOD, CAT, and LZM activities. Meanwhile, some interactive effects of M. aeruginosa , hypoxia and time were observed. Independently of the presence or absence of hypoxia, toxic algal exposure generally increased the five tested enzyme activities of haemolymph, except CAT. Although half of microcystin could be eliminated after 7 days depuration, toxic M. aeruginosa or hypoxia exposure history showed some latent effects on most parameters. These results revealed that toxic algae play an important role on haemolymph parameters alterations and its toxic effects could be affected by hypoxia. Although the microcystin depuration rate of H. cumingii is quick, toxic M. aeruginosa and/or hypoxia exposure history influenced its immunological mechanism recovery. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
239. Allelopathic interactions between the HAB dinoflagellate Ostreopsis cf. ovata and macroalgae.
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Accoroni, Stefano, Percopo, Isabella, Cerino, Federica, Romagnoli, Tiziana, Pichierri, Salvatore, Perrone, Cesira, and Totti, Cecilia
- Subjects
- *
ALLELOPATHIC agents , *SPECIES distribution , *DINOFLAGELLATES , *ALGAL blooms , *ALGAL toxins , *BENTHIC ecology - Abstract
Intense blooms of the toxic benthic dinoflagellate Ostreopsis cf. ovata have been a recurrent phenomenon along several Mediterranean coasts during summer in the last few years. These blooms are often associated with noxious effects on humans and deaths of benthic invertebrates. Previous studies carried out on the Conero Riviera (northern Adriatic Sea) highlighted that Ostreopsis abundances recorded on rocks were significantly higher than on the surface of seaweeds, suggesting that some allelopathic interactions might occur between Ostreopsis and macroalgal substrates. In this study we investigated under experimental conditions the interactions between O . cf. ovata and three of the most common macroalgae in this area: Dictyota dichotoma (brown alga), Rhodymenia pseudopalmata (red alga) and Ulva rigida (green alga). Three different experiments were set up: O . cf. ovata was grown (i) together with fresh macroalgal tissues, (ii) in media in which macroalgae were previously cultured, and (iii) in media with the addition of dry macroalgal powder at different concentrations. The results indicated that all the investigated seaweeds exerted negative effects toward the benthic dinoflagellate O. cf. ovata. D. dichotoma inhibited the growth of O . cf. ovata in all tested experimental conditions; U. rigida had inhibitory effect both in form of fresh thalli and dry powder but not as growth medium filtrate, suggesting that either Ulva does not release any allelopathic compound in the medium in absence of O. cf. ovata or the alleged released allelochemicals are rapidly degradable. Neither the fresh thalli of R. pseudopalmata or the filtrate of its culture medium showed any inhibitory effects, while a negative effect was only observed at high concentrations of dry thallus powder. With the exception of D. dichotoma co-culture experiment, a complete algicidal effect was never observed partly because O. cf. ovata produced a large amount of resting stages, which permitted its survival. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
240. Phytoplankton Community Shifts and Harmful Algae Presence in a Diversion Influenced Estuary.
- Author
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Riekenberg, Jessica, Bargu, Sibel, and Twilley, Robert
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AQUATIC habitats ,ESTUARIES ,PHYTOPLANKTON ,STREAM chemistry ,ALGAL toxins ,BIOMASS - Abstract
River water entering estuaries affects the physical and chemical environment at irregular intervals creating a highly dynamic aquatic habitat. Phytoplankton are important primary producers in estuaries that respond quickly to their changing environment. Over a 12-month period, the phytoplankton response was examined in terms of biomass, abundance, community composition, and potential phycotoxin production to seasonal changes in river input entering the Breton Sound Estuary in Louisiana. Chlorophyll a (chl a) measurements estimated phytoplankton biomass and light microscopy identified phytoplankton abundance and community composition. Phycotoxins were measured using ultra-sensitive enzyme-linked immunosorbent assay (ELISA). During the study period, chl a and cell abundances exhibited an inverse relationship with the seasons, which were determined by temperature and diversion input rates. The community was dominated by cyanobacteria for most of the year, mainly corresponding to the warm-low flow season. For the rest of the year, cyanobacteria decreased while chlorophytes and centric diatoms increased to approximately equal contributions. Overall, the phytoplankton community composition was most commonly moderated by temperature, salinity, and dissolved inorganic nitrogen (DIN) availability using BIO-ENV. Microcystins (MCs) were detected throughout the year ranging from below detection to 2.92 μg MCs l. MC levels were highest during the warm-low flow season and toward the lower estuary. The detection of MCs for the first time in the Breton Sound Estuary illustrates a potential risk to human health and economically important estuarine food webs. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
241. Simulating the vertical dynamics of phosphate and their effects on the growth of harmful algae.
- Author
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Yamaguchi, Haruo and Sai, Koji
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- *
COASTS , *PHOSPHATES , *ALGAL growth , *EUPHOTIC zone , *STRATIGRAPHIC geology , *ECOLOGICAL research - Abstract
A large amount of inorganic phosphate (P i ) is required for harmful planktonic algae to proliferate extensively in enclosed coastal regions. However, P i in surface euphotic waters is typically deficient during warm season when the waters are stratified. Mixing events that redistribute the large amount of P i in bottom waters can therefore have large ecological effects, making understanding such events important. In this study, we simulated the vertical dynamics of P i in an enclosed coastal region, Uranouchi Inlet, Japan, and discuss their potential effects on harmful algal blooms using algal growth kinetics. Our results indicated that our one-dimensional model is capable of reproducing empirically observed variations in the water column of the inlet. In simulations, during the warm season, the water column became vertically stratified when the wind velocity was weak (less than 2.4 m s −1 ), but mixed completely within 20 h under a strong wind (over 6 m s −1 ). The flux of P i from the lower to the upper layer during such a mixing event was calculated to be 0.472–2.22 μmol L −1 day −1 , two orders of magnitude higher than under stratified conditions (0.00230–0.0108 μmol L −1 day −1 ). Our analyses demonstrated that the concentration of P i vertically supplied within one day during such mixing events has a great potential for supporting the massive proliferation of harmful algae such as Chattonella antiqua and Heterocapsa circularisquama . [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
242. A PDE system modeling the competition and inhibition of harmful algae with seasonal variations.
- Author
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Wang, Feng-Bin
- Subjects
- *
PARTIAL differential equations , *GLOBAL asymptotic stability , *REACTION-diffusion equations , *ADVECTION-diffusion equations , *MATHEMATICAL models , *ALGAE , *CLIMATE change - Abstract
In this paper, we study a reaction–diffusion–advection system modeling the competition of harmful algae with seasonal variations in a flowing water habitat. We assume that harmful algae produce toxins, which have inhibitory effects on their algal competitors, that is, the produced toxins can inhibit the growth of its competitor. For the single population model, we prove that the algae will be washed out eventually if the trivial periodic state is locally asymptotically stable, while there exists a unique positive periodic state which is globally attractive if the trivial periodic state is unstable. When there is mutual invasibility of both semitrivial periodic solutions of the two-species model, we are able to prove the existence of periodic coexistence state. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
243. Development and validation of PCR-RFLP assay for identification of Gambierdiscus species in the Greater Caribbean Region
- Author
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Lozano-Duque, Yesid, Richlen, Mindy L., Smith, Tyler B., Anderson, Donald M., and Erdner, Deana L.
- Published
- 2018
- Full Text
- View/download PDF
244. First Report of Domoic Acid Production from
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Cecil Tenorio, Eduardo Uribe, Michael Araya, Natalia Arakaki, Sonia Quijano-Scheggia, Francisco Álvarez, Juan Blanco, Gonzalo Alvarez, and Melissa Perez-Alania
- Subjects
0106 biological sciences ,Argopecten purpuratus ,Health, Toxicology and Mutagenesis ,Neurotoxins ,ITS2 ,Zoology ,Toxicology ,01 natural sciences ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,Aquaculture ,Amnesic shellfish poisoning ,Phytoplankton ,Peru ,harmful algae ,Phylogeny ,030304 developmental biology ,Diatoms ,0303 health sciences ,Kainic Acid ,biology ,business.industry ,010604 marine biology & hydrobiology ,Domoic acid ,biology.organism_classification ,scallop ,chemistry ,Bays ,Scallop ,Medicine ,Marine Toxins ,business ,Pseudo-nitzschia ,Bay ,amnesic shellfish poisoning ,Environmental Monitoring - Abstract
The Peruvian sea is one of the most productive ecosystems in the world. Phytoplankton production provides food for fish, mammals, mollusks and birds. This trophic network is affected by the presence of toxic phytoplankton species. In July 2017, samples of phytoplankton were obtained from Paracas Bay, an important zone for scallop (Argopecten purpuratus) aquaculture in Peru. Morphological analysis revealed the presence of the genus Pseudo-nitzschia, which was isolated and cultivated in laboratory conditions. Subsequently, the monoclonal cultures were observed by scanning electron microscopy (SEM), and identified as P. multistriata, based on both the morphological characteristics, and internal transcribed spacers region (ITS2) sequence phylogenetic analysis. Toxin analysis using liquid chromatography (LC) with high-resolution mass spectrometry (HRMS) revealed the presence of domoic acid (DA) with an estimated amount of 0.004 to 0.010 pg cell−1. This is the first report of DA from the coastal waters of Peru and its detection in P. multistriata indicates that it is a potential risk. Based on our results, routine monitoring of this genus should be considered in order to ensure public health.
- Published
- 2021
245. Development of charged liposomal delivery system for enhanced algicidal effect of DP-92
- Author
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Yu Jin Cho and Jun-Pil Jee
- Subjects
Harmful algae ,Liposome ,Algicidal activity ,Delivery system ,Therapeutics. Pharmacology ,RM1-950 - Published
- 2016
- Full Text
- View/download PDF
246. PSP-producing dinoflagellate Alexandrium minutum induces valve microclosures in the mussel Mytilus galloprovincialis
- Author
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Réjean Tremblay, Luc A. Comeau, José M. F. Babarro, Michael Scarratt, Michel Starr, Pilar Riobó, and Ministerio de Economía y Competitividad (España)
- Subjects
Heterocapsa triquetra ,Alexandrium minutum ,Valve gape ,Zoology ,Valve opening ,Aquatic Science ,03 medical and health sciences ,Phytoplankton ,medicine ,Harmful algae ,Paralytic shellfish poisoning ,030304 developmental biology ,0303 health sciences ,biology ,fungi ,Dinoflagellate ,04 agricultural and veterinary sciences ,Mussel ,medicine.disease ,biology.organism_classification ,Mytilus ,Mytilus galloprovincialis ,040102 fisheries ,0401 agriculture, forestry, and fisheries - Abstract
7 pages, 4 figures, 1 table, The saxitoxin-producing dinoflagellate Alexandrium minutum is a well-known microalga that causes paralytic shellfish poisoning (PSP) in many coastal regions of the world. In this study, we measured the valve movements of cultivated mussels Mytilus galloprovincialis feeding on toxic A. minutum (n = 29 mussels, shell length = 67.1 ± 3.2 mm, x̅ ± SD) or a morphologically-similar, but toxin-free phytoplankton, Heterocapsa triquetra (n = 24 mussels, shell length = 68.3 ± 2.9 mm). Phytoplankton inoculations were conducted in three sequential “pulses” intended to increase microalgal cell concentrations in a stepwise manner up to ~5000 cells l−1 over a 9-h period. M. galloprovincialis was connected to a non-invasive valvometry apparatus that concurrently measured the magnitude of valve openness once every 0.1 s. It was found that M. galloprovincialis tended to keep its valves open over the course of the experiment, regardless of the phytoplankton species present in water. Standard valve opening metrics, such as the opening duration and opening amplitude, were not significantly affected by the species of phytoplankton. However, the frequency of brief and partial valve closures (microclosures) was significantly influenced by phytoplankton species (P, Financial support was provided by Fisheries and Oceans Canada and the Spanish government through the Ministerio de Economía y Competitividad (projects AGL2013-45945-R and CTM2016-76146-C3-2-R)
- Published
- 2019
247. Plastic-associated harmful microalgal assemblages in marine environment
- Author
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Fabio Varriale, Paolo Moretto, Maria Grazia Giacobbe, Samuela Capellacci, Silvia Casabianca, Nicola Ungaro, Antonella Penna, Luciana Tartaglione, Riccardo Narizzano, A. Dagnino, Enrico Barbone, R. Bertolotto, Carmela Dell'Aversano, Fulvia Risso, Casabianca, Silvia, Capellacci, Samuela, Giacobbe, Maria Grazia, Dell'Aversano, Carmela, Tartaglione, Luciana, Varriale, Fabio, Narizzano, Riccardo, Risso, Fulvia, Moretto, Paolo, Dagnino, Alessandro, Bertolotto, Rosella, Barbone, Enrico, Ungaro, Nicola, and Penna, Antonella
- Subjects
010504 meteorology & atmospheric sciences ,Assemblages ,Health, Toxicology and Mutagenesis ,Microorganism ,biotoxins ,010501 environmental sciences ,Toxicology ,medicine.disease_cause ,01 natural sciences ,Biotoxin ,Abundance (ecology) ,marine plastics ,Microalgae ,medicine ,harmful algae ,Humans ,0105 earth and related environmental sciences ,Trophic level ,Diatoms ,Waste Products ,biology ,Toxin ,Ecology ,Assemblage ,Dinoflagellate ,Dispersal ,General Medicine ,Substrate (biology) ,biology.organism_classification ,Pollution ,qPCR ,Assemblages Dispersal Harmful algae Biotoxins Marine plastics qPCR ,Diatom ,Marine plastic ,Dinoflagellida ,Biological dispersal ,Marine Toxins ,Plastics ,Environmental Monitoring - Abstract
Plastic debris carry fouling a variety of class-size organisms, among them harmful microorganisms that potentially play a role in the dispersal of allochthonous species and toxic compounds with ecological impacts on the marine environment and human health. We analyzed samples of marine plastics floating at the sea surface using a molecular qPCR assay to quantify the attached microalgal taxa, in particular, harmful species. Diatoms were the most abundant group of plastic colonizers with maximum abundance of 8.2 x 10(4) cells cm(-2) of plastics, the maximum abundance of dinoflagellates amounted to 1.1 x 10(3) cells cm(-2) of plastics. The most abundant harmful microalgal taxon was the diatom Pseudo-nitzschia spp., including at least 12 toxic species, and the dinoflagellate Ostreopsis cf. ovata with 6606 and 259 cells cm(-2), respectively. The abundance of other harmful microalgal species including the toxic allochthonous dinoflagellate Alexandrium pacificum ranged from 1 to 73 cells cm(-2). In the present study, a direct relationship between the abundance of harmful algal species colonizing the plastic substrates and their toxin production was found. The levels of potential toxins on plastic samples ranged from 101 to 10(2) ng cm(-2), considering the various toxin families produced by the colonized harmful microalgal species. We also measured the rate of adhesion by several target microalgal species. It ranged from 1.8 to 0.3 day(-1) demonstrating the capacity of plastic substrate colonizing rapidly by microalgae. The present study reports the first estimates of molecular quantification of microorganisms including toxin producing species that can colonize plastics. Such findings provide important insights for improving the monitoring practice of plastics and illustrate how the epi-plastic community can exacerbate the harmful effects of plastics by dispersal, acting as an alien and toxic species carrier and potentially being ingested through the marine trophic web. (C) 2018 Elsevier Ltd. All rights reserved.
- Published
- 2019
248. Recent Trends in Marine Phycotoxins from Australian Coastal Waters
- Author
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Penelope Ajani, D. Tim Harwood, and Shauna A. Murray
- Subjects
harmful algae ,ciguatoxins ,paralytic shellfish toxins ,okadaic acid ,domoic acid ,palytoxins ,karlotoxins ,tetrodotoxin ,maitotoxin ,palytoxin ,Biology (General) ,QH301-705.5 - Abstract
Phycotoxins, which are produced by harmful microalgae and bioaccumulate in the marine food web, are of growing concern for Australia. These harmful algae pose a threat to ecosystem and human health, as well as constraining the progress of aquaculture, one of the fastest growing food sectors in the world. With better monitoring, advanced analytical skills and an increase in microalgal expertise, many phycotoxins have been identified in Australian coastal waters in recent years. The most concerning of these toxins are ciguatoxin, paralytic shellfish toxins, okadaic acid and domoic acid, with palytoxin and karlotoxin increasing in significance. The potential for tetrodotoxin, maitotoxin and palytoxin to contaminate seafood is also of concern, warranting future investigation. The largest and most significant toxic bloom in Tasmania in 2012 resulted in an estimated total economic loss of~AUD$23M, indicating that there is an imperative to improve toxin and organism detection methods, clarify the toxin profiles of species of phytoplankton and carry out both intra‐ and inter‐species toxicity comparisons. Future work also includes the application of rapid, real‐time molecular assays for the detection of harmful species and toxin genes. This information, in conjunction with a better understanding of the life histories and ecology of harmful bloom species, may lead to more appropriate management of environmental, health and economic resources.
- Published
- 2017
- Full Text
- View/download PDF
249. Effects of Two Toxin-Producing Harmful Algae, Alexandrium catenella and Dinophysis acuminata (Dinophyceae), on Activity and Mortality of Larval Shellfish
- Author
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Sarah K. D. Pease, Michael L. Brosnahan, Marta P. Sanderson, and Juliette L. Smith
- Subjects
Health, Toxicology and Mutagenesis ,fungi ,food and beverages ,Toxicology ,saxitoxin ,okadaic acid ,pectenotoxin ,Alexandrium catenella ,Dinophysis acuminata ,Crassostrea virginica ,harmful algae ,harmful algal bloom ,oyster larvae ,shellfish - Abstract
Harmful algal bloom (HAB) species Alexandrium catenella and Dinophysis acuminata are associated with paralytic shellfish poisoning (PSP) and diarrhetic shellfish poisoning (DSP) in humans, respectively. While PSP and DSP have been studied extensively, less is known about the effects of these HAB species or their associated toxins on shellfish. This study investigated A. catenella and D. acuminata toxicity in a larval oyster (Crassostrea virginica) bioassay. Larval activity and mortality were examined through 96-h laboratory exposures to live HAB cells (10–1000 cells/mL), cell lysates (1000 cells/mL equivalents), and purified toxins (10,000 cells/mL equivalents). Exposure to 1000 cells/mL live or lysed D. acuminata caused larval mortality (21.9 ± 7.0%, 10.2 ± 4.0%, respectively) while exposure to any tested cell concentration of live A. catenella, but not lysate, caused swimming arrest and/or mortality in >50% of larvae. Exposure to high concentrations of saxitoxin (STX) or okadaic acid (OA), toxins traditionally associated with PSP and DSP, respectively, had no effect on larval activity or mortality. In contrast, pectenotoxin-2 (PTX2) caused rapid larval mortality (49.6 ± 5.8% by 48 h) and completely immobilized larval oysters. The results indicate that the toxic effects of A. catenella and D. acuminata on shellfish are not linked to the primary toxins associated with PSP and DSP in humans, and that PTX2 is acutely toxic to larval oysters.
- Published
- 2022
250. Abundant Species Diversity and Essential Functions of Bacterial Communities Associated with Dinoflagellates as Revealed from Metabarcoding Sequencing for Laboratory-Raised Clonal Cultures
- Author
-
Yunyan Deng, Kui Wang, Zhangxi Hu, and Ying-Zhong Tang
- Subjects
Bacteria ,Actinobacteria ,algae-associated bacterial community ,dinoflagellate ,harmful algae ,methylotrophs ,RNA, Ribosomal, 16S ,Health, Toxicology and Mutagenesis ,Dinoflagellida ,Public Health, Environmental and Occupational Health ,High-Throughput Nucleotide Sequencing ,Humans ,Ecosystem ,Phylogeny - Abstract
Interactions between algae and bacteria represent an important inter-organism association in aquatic environments, which often have cascading bottom-up influences on ecosystem-scale processes. Despite the increasing recognition of linkages between bacterioplankton and dynamics of dinoflagellate blooms in the field, knowledge about the forms and functions of dinoflagellate-bacteria associations remains elusive, mainly due to the ephemeral and variable conditions in the field. In this study, we characterized the bacterial community associated with laboratory cultures of 144 harmful algal strains, including 130 dinoflagellates (covering all major taxonomic orders of dinoflagellates) and 14 non-dinoflagellates, via high-throughput sequencing for 16S rRNA gene amplicons. A total of 4577 features belonging to bacteria kingdom comprising of 24 phyla, 55 classes, 134 orders, 273 families, 716 genera, and 1104 species were recovered from the algal culture collection, and 3 phyla (Proteobacteria, Bacteroidetes, and Firmicutes) were universally present in all the culture samples. Bacterial communities in dinoflagellates cultures exhibited remarkable conservation across different algal strains, which were dominated by a relatively small number of taxa, most notably the γ-proteobacteria Methylophaga, Marinobacter and Alteromonas. Although the bacterial community composition between dinoflagellates and non-dinoflagellate groups did not show significant difference in general, dinoflagellates harbored a large number of unique features (up to 3811) with relatively low individual abundance and enriched in the potential methylotrophs Methylophaga. While the bacterial assemblages associated with thecate and athecate dinoflagellates displayed no general difference in species composition and functional groups, athecate dinoflagellates appeared to accommodate more aerobic cellulolytic members of Actinobacteria, implying a more possible reliance on cellulose utilization as energy source. The extensive co-occurrence discovered here implied that the relationships between these algal species and the bacterial consortia could be viewed as either bilaterally beneficial (i.e., mutualism) or unilaterally beneficial at least to one party but virtually harmless to the other party (i.e., commensalism), whereas both scenarios support a long-term and stable co-existence rather than an exclusion of one or the other. Our results demonstrated that dinoflagellates-associated bacterial communities were similar in composition, with enrichment of potential uncultured methylotrophs to one-carbon compounds. This work enriches the knowledge about the fundamental functions of bacteria consortia associated with the phycospheres of dinoflagellates and other HABs-forming microalgae.
- Published
- 2022
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