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Eugene F. Stoermer - One of the best experts on this subject based on the ideXlab platform.
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local extirpation of Stephanodiscus niagarae bacillariophyceae in the recent limnological record of lake ontario
Journal of Phycology, 1998Co-Authors: Matthew L Julius, Eugene F. Stoermer, Christine M Taylor, Claire L SchelskeAbstract:We investigated microfossil assemblages in recent sediments from nine stations across Lake Ontario. Stephanodiscus niagarae was not present in any of these sediment samples, marking the taxon’s extirpation from its type locality. This observation documents the end of a general reduction in size and alteration in valve morphology associated with habitat disturbance. Stephanodiscus niagarae may have been directly eliminated from the lake, or sexual reproduction may have been delayed beyond the species’ ability to sustain numbers through asexual reproduction.
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SEXUAL REPRODUCTION IN Stephanodiscus NIAGARAE (BACILLARIOPHYTA) 1
Journal of Phycology, 1991Co-Authors: Mark B. Edlund, Eugene F. StoermerAbstract:We observed sexual reproduction in a clonal culture of Stephanodiscus niagarae Ehrenb. and used light and scanning electron microscopy to absent flagellated male cells, auxospore growth, initial valve structure and production, and subsequent daughter cell division. Free auxospores were spherical and nonsiliceous throughout growth, producing hemispherical initial valves devoid of spines and with nonfasciculate striae. Pregametangial cells averaged 43% of the diameter of the daughter cell population and were 1/9 the biovolume of initial, cells. This paper is the first confirmed report of sexual reproduction in S. niagarae, although it appears that specimens of Actinocyclus niagarae H. L. Smith, described from Lake Erie in 1878, are actually initial valves of S. niagarae.
Minkyung Han - One of the best experts on this subject based on the ideXlab platform.
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enhancement of algicidal activity by immobilization of algicidal bacteria antagonistic to Stephanodiscus hantzschii bacillariophyceae
Journal of Applied Microbiology, 2007Co-Authors: Yoonho Kang, B R Kim, Hyosung Choi, Joobeom Seo, Baik Ho Kim, Minkyung HanAbstract:Aims: Enhancement of algicidal activity by immobilization of algicidal bacteria antagonistic to Stephanodiscus hantzschii. Methods and Results: In laboratory studies, A diatom-lysing bacterium, Pseudomonas fluorescens HYK0210-SK09 showed strong algicidal activity against S. hantzschii, but a natural mesocosm study revealed that this bacterium failed to fully control natural blooms of Stephanodiscus at the low water temperatures that favour these blooms. Here, we sought to develop an effective immobilization strategy for enhancing the algicidal activity of HYK0210-SK09 in the natural setting. Bacterium HYK0210-SK09 was immobilized with various carriers including agar, alginate, polyurethane and cellulose sponge. The bacterial cells immobilized with cellulose sponge (CIS) induced more rapid and complete lysis of S. hantzschii than other carriers, and had a higher packing ability than polyurethane. Furthermore, CIS-immobilized cells showed higher lysis of S. hantzschii at the same concentrations as that of free cells (≤1 × 107 cells ml−1), and had especially strong algicidal activity at the low temperatures (<10°C). Based on these laboratory studies, we assessed the possible application of HYK0210-SK09 cells in the field by performing a mesocosm study during the winter season. The CIS-immobilized cells with species-specific activity towards the genera Stephanodiscus showed extremely high algicidal activity (up to 95%) against a bloom of Stephanodiscus hantzschii even at low water temperatures, because of high cell packing and subsequent cell protection against low temperatures and predators, whereas free cells showed negligible algicidal activities under these conditions. Conclusion: Immobilizing cells of HYK0210-SK09 in CIS foam, rather than in the other matrices tested, could achieve more efficient control of Stephanodiscus blooms and showed a significant algicidal activity on in vitro and in vivo blooms, even at low water temperature. Significance and Impact of the Study: Collectively, these results indicate that CIS of algicidal bacteria may form an important strategy for effective management of Stephanodiscus blooms at low water temperatures.
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isolation and characterization of a bio agent antagonistic to diatom Stephanodiscus hantzschii
Journal of Applied Microbiology, 2005Co-Authors: Yoonho Kang, Baik Ho Kim, Jae Dong Kim, Dongsoo Kong, Minkyung HanAbstract:Y.-H. KANG, J.-D. KIM, B.-H. KIM, D.-S. KONG AND M.-S. HAN. 2005. Aims: Identification of bacterium HYK0203-SK02 and its lysis of Stephanodiscus hantzschii. Methods and Results: In an effort to identify a bio-agent capable of controlling S. hantzschii blooms, we used the algal lawn method to identify 76 bacteria in relevant water samples. Of these, the seven isolate showed algicidal activity against S. hantzschii; isolate HYK0203-SK02 exhibited the strongest algicidal activity, and was used for further analysis. 16S rDNA sequencing of this isolate allowed us to identify HYK0203-SK02 as a strain of Pseudomonas putida (99AE2%). Growth of S. hantzschii was strongly suppressed by bacteria in all growth phases, with the strongest algicidal activity noted against diatoms in the exponential stage (5‐18 days). Host range assays revealed that isolate HYK0203-SK02 also strongly inhibited the growth of Microcystis aeruginosa, but stimulated growth of the diatom Cyclotella sp., which has a similar structure to that of S. hantzschii. Biochemical assays revealed that the algicidal substance seemed to be localized in the cytoplasmic membrane of this newly identified algicidal bacterium. Conclusion: The algicidal bacteria P. putida HYK0203-SK02 caused cell lysis and death of not only diatom S. hantzschii but also cyanobacteria M. aeruginosa, dramatically. Algicidal substance might be located at the compartment of cytoplasmic membrane. Significance and Impact of the Study: Taken together, our results indicate that P. putida HYK0203-SK02 may be a potential bio-agent for future use in controlling freshwater diatomic blooms.
Fabiola Cruces - One of the best experts on this subject based on the ideXlab platform.
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observations and comments on the diatom Stephanodiscus minutulus kutzing cleve moller bacillariophyceae found for the first time in chile from bottom sediments collected in lake laja observaciones y comentarios acerca de la diatomea Stephanodiscus minutulus kutzing cleve moller bacillariophyceae encontrada por primera vez en chile en sedimentos recolectados en el lago laja
2010Co-Authors: Fabiola Cruces, Centro EulaAbstract:This study reports the presence of the diatom Stephanodiscus minutulus (Kutzing) Cleve & Moller for the first time in Chilean continental waters; it is a taxon reported in many aquatic systems in Europe and North America and there are only scanty records from South America (Argentina). The species was found in a sedimentary profile collected from Lake Laja (Andes Mountains), Central Chile. The principal morphological features of S. minutulus are described, and comments about its relationship with other closely related taxa are given.
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observations and comments on the diatom Stephanodiscus minutulus kutzing cleve moller bacillariophyceae found for the first time in chile from bottom sediments collected in lake laja
Gayana Botanica, 2010Co-Authors: Fabiola Cruces, Patricio Rivera, Roberto UrrutiaAbstract:En este estudio se senala la presencia de la diatomea Stephanodiscus minutulus (Kutzing) Cleve & Moller por primera vez para aguas continentales de Chile; es un taxon muy comun en diversos sistemas acuaticos de Europa y Norteamerica, y para Sudamerica solo existen escasos registros en Argentina. La especie fue encontrada en un perfl sedimentario colectado en el Lago Laja (Cordillera de los Andes), Chile central. Se describen las principales caracteristicas morfologicas de S. minutulus y se entregan comentarios sobre su relacion con otras especies cercanas.
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Stephanodiscus kuetzingii klee casper bacillariophyceae from living material collected in rapel reservoir central chile
Diatom Research, 2005Co-Authors: Patricio Rivera, Fabiola CrucesAbstract:Stephanodiscus kuetzingii Klee & Casper, described from a Pleistocene deposit in the Luneburger Heide, Lower Saxony, Germany (Kutzing type material for Cyclotella minutula), was found living in Rapel Reservoir, Central Chile. There are no published records of living material for this species. Its valve morphology was studied using light and scanning electron microscopy. The morphological features of the Chilean specimens are in good agreement with those of S. kuetzingii described by Klee and Casper. The present study provides additional information on rimoportula structure, in which a long external tube was observed, as well as on the presence of a narrow circumferential hyaline area at the valve face/mantle junction of convex valves. The similarities and differences between S. kuetzingii and other closely related Stephanodiscus species are discussed.
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primera cita de Stephanodiscus agassizensis hakansson kling bacillariophyceae en chile
Gayana Botanica, 2002Co-Authors: Patricio Rivera, Fabiola Cruces, Irma VilaAbstract:Se senala por primera vez para Chile a Stephanodiscus agassizensis Hakkansson & Kling (Stephanodiscaceae). La especie fue encontrada en una muestra proveniente del Lago Chungara (18°14'S, 69°09'W), y el material analizado esta depositado en la Coleccion Diatomologica de la Universidad de Concepcion, Chile. Fotomicrografias obtenidas en los microscopios fotonico y electronico de barrido muestran las principales caracteristicas mor-fologicas de este taxon
Yoonho Kang - One of the best experts on this subject based on the ideXlab platform.
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use of immobilized algicidal bacteria to control natural freshwater diatom blooms
Hydrobiologia, 2012Co-Authors: Yoonho Kang, Seung Won JungAbstract:The purpose of this investigation was to assess the possible use of algicidal bacteria in conjunction with an immobilization technique for efficient termination of natural blooms of Stephanodiscus concomitant with minimization of adverse effects caused by a single application of bacteria. The performance of Pseudomonas fluorescens cells immobilized on cellulose sponges (CIS) was compared with that of freely suspended cells (FSC) of the organism at low water temperature (WT) of <10°C in co-cultures and natural microcosms. In the co-cultures, CIS resulted in more effective lysis of Stephanodiscus, irrespective of similar bacterivore (Spumella sp.) density, and significantly reduced the concentrations of nitrate and soluble reactive phosphorus (SRP), but not that of silicate, compared with FSC. In the microcosms containing natural freshwater, CIS reduced the densities of Stephanodiscus spp. and Aulacoseira spp. but had no effect on other phytoplankton. Compared with FSC, removal of nutrients by the CIS prevented secondary blooms caused by other phytoplankton. Our results indicate that the CIS affords effective protection of P. fluorescens from low WT and heterotrophs, and restrained regeneration of both SRP and nitrate. Thus, it was demonstrated that the CIS may be an attractive alternative to FSC for control of natural blooms.
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enhancement of algicidal activity by immobilization of algicidal bacteria antagonistic to Stephanodiscus hantzschii bacillariophyceae
Journal of Applied Microbiology, 2007Co-Authors: Yoonho Kang, B R Kim, Hyosung Choi, Joobeom Seo, Baik Ho Kim, Minkyung HanAbstract:Aims: Enhancement of algicidal activity by immobilization of algicidal bacteria antagonistic to Stephanodiscus hantzschii. Methods and Results: In laboratory studies, A diatom-lysing bacterium, Pseudomonas fluorescens HYK0210-SK09 showed strong algicidal activity against S. hantzschii, but a natural mesocosm study revealed that this bacterium failed to fully control natural blooms of Stephanodiscus at the low water temperatures that favour these blooms. Here, we sought to develop an effective immobilization strategy for enhancing the algicidal activity of HYK0210-SK09 in the natural setting. Bacterium HYK0210-SK09 was immobilized with various carriers including agar, alginate, polyurethane and cellulose sponge. The bacterial cells immobilized with cellulose sponge (CIS) induced more rapid and complete lysis of S. hantzschii than other carriers, and had a higher packing ability than polyurethane. Furthermore, CIS-immobilized cells showed higher lysis of S. hantzschii at the same concentrations as that of free cells (≤1 × 107 cells ml−1), and had especially strong algicidal activity at the low temperatures (<10°C). Based on these laboratory studies, we assessed the possible application of HYK0210-SK09 cells in the field by performing a mesocosm study during the winter season. The CIS-immobilized cells with species-specific activity towards the genera Stephanodiscus showed extremely high algicidal activity (up to 95%) against a bloom of Stephanodiscus hantzschii even at low water temperatures, because of high cell packing and subsequent cell protection against low temperatures and predators, whereas free cells showed negligible algicidal activities under these conditions. Conclusion: Immobilizing cells of HYK0210-SK09 in CIS foam, rather than in the other matrices tested, could achieve more efficient control of Stephanodiscus blooms and showed a significant algicidal activity on in vitro and in vivo blooms, even at low water temperature. Significance and Impact of the Study: Collectively, these results indicate that CIS of algicidal bacteria may form an important strategy for effective management of Stephanodiscus blooms at low water temperatures.
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isolation and characterization of a bio agent antagonistic to diatom Stephanodiscus hantzschii
Journal of Applied Microbiology, 2005Co-Authors: Yoonho Kang, Baik Ho Kim, Jae Dong Kim, Dongsoo Kong, Minkyung HanAbstract:Y.-H. KANG, J.-D. KIM, B.-H. KIM, D.-S. KONG AND M.-S. HAN. 2005. Aims: Identification of bacterium HYK0203-SK02 and its lysis of Stephanodiscus hantzschii. Methods and Results: In an effort to identify a bio-agent capable of controlling S. hantzschii blooms, we used the algal lawn method to identify 76 bacteria in relevant water samples. Of these, the seven isolate showed algicidal activity against S. hantzschii; isolate HYK0203-SK02 exhibited the strongest algicidal activity, and was used for further analysis. 16S rDNA sequencing of this isolate allowed us to identify HYK0203-SK02 as a strain of Pseudomonas putida (99AE2%). Growth of S. hantzschii was strongly suppressed by bacteria in all growth phases, with the strongest algicidal activity noted against diatoms in the exponential stage (5‐18 days). Host range assays revealed that isolate HYK0203-SK02 also strongly inhibited the growth of Microcystis aeruginosa, but stimulated growth of the diatom Cyclotella sp., which has a similar structure to that of S. hantzschii. Biochemical assays revealed that the algicidal substance seemed to be localized in the cytoplasmic membrane of this newly identified algicidal bacterium. Conclusion: The algicidal bacteria P. putida HYK0203-SK02 caused cell lysis and death of not only diatom S. hantzschii but also cyanobacteria M. aeruginosa, dramatically. Algicidal substance might be located at the compartment of cytoplasmic membrane. Significance and Impact of the Study: Taken together, our results indicate that P. putida HYK0203-SK02 may be a potential bio-agent for future use in controlling freshwater diatomic blooms.
Mark B. Edlund - One of the best experts on this subject based on the ideXlab platform.
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Stephanodiscus coruscus sp nov a new species of diatom bacillariophyta from june lake california usa with close affiliation to Stephanodiscus klamathensis
Diatom Research, 2020Co-Authors: Jeffery R Stone, Mark B. Edlund, Laura C Streib, Hung Ha Quang, Michael M McglueAbstract:Modern and fossil populations of a Stephanodiscus Ehrenberg species from June Lake, California (USA) were analysed using light and scanning electron microscopy (SEM). Stephanodiscus valves were a m...
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Paleolimnology of a freshwater estuary to inform Area of Concern nutrient delisting efforts
Journal of Paleolimnology, 2018Co-Authors: Elizabeth E. Alexson, Mark B. Edlund, Euan D. Reavie, Richard P. Axler, Sergiy V. Yemets, Pavel A. Krasutsky, Robert W. Pillsbury, Diane DesotelleAbstract:The St. Louis River Estuary (SLRE), a freshwater estuary bordering Duluth, Minnesota, Superior, Wisconsin, and the most western point of Lake Superior (46.74°, − 92.13°), has a long history of human development since Euro-American settlement ~ 200 years ago. Due to degradation from logging, hydrologic modification, industrial practices, and untreated sewage, the SLRE was designated an Area of Concern in 1987. Action has been taken to restore water quality including the installation of the Western Lake Superior Sanitary District in 1978 to help remove beneficial use impairments. A better understanding of historical impacts and remediation is necessary to help document progress and knowledge gaps related to water quality, so a paleolimnological study of the SLRE was initiated. Various paleolimnological indicators (pigments, diatom communities, and diatom-inferred phosphorus) were analyzed from six cores taken throughout the SLRE and another from western Lake Superior. Reductions in eutrophic diatom taxa such as Cyclotella meneghiniana and Stephanodiscus after 1970 in certain cores suggest an improvement in water quality over the last 40 years. However, in cores taken from estuarine bay environments, persistence of eutrophic taxa such as Cyclostephanos dubius and Stephanodiscus binderanus indicate ongoing nutrient problems. Sedimentary pigments also indicate cyanobacteria increases in bays over the last two decades. Diatom model-inferred phosphorus and contemporary monitoring data suggest some of the problems associated with excess nutrient loads have been remediated, but modern conditions (internal phosphorus loading, changing climate) may be contributing to ongoing water quality impairments in some locations. The integrated record of biological, chemical, and physical indicators preserved in the sediments will aid state and federal agencies in determining where to target their resources.
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SEXUAL REPRODUCTION IN Stephanodiscus NIAGARAE (BACILLARIOPHYTA) 1
Journal of Phycology, 1991Co-Authors: Mark B. Edlund, Eugene F. StoermerAbstract:We observed sexual reproduction in a clonal culture of Stephanodiscus niagarae Ehrenb. and used light and scanning electron microscopy to absent flagellated male cells, auxospore growth, initial valve structure and production, and subsequent daughter cell division. Free auxospores were spherical and nonsiliceous throughout growth, producing hemispherical initial valves devoid of spines and with nonfasciculate striae. Pregametangial cells averaged 43% of the diameter of the daughter cell population and were 1/9 the biovolume of initial, cells. This paper is the first confirmed report of sexual reproduction in S. niagarae, although it appears that specimens of Actinocyclus niagarae H. L. Smith, described from Lake Erie in 1878, are actually initial valves of S. niagarae.
