Biotic and Abiotic Factors Affecting the Population Dynamics of Ceratium hirundinella, Peridinium cinctum, and Peridiniopsis elpatiewskyi

The present research was conducted to assess the impact of abiotic and biotic factors on the growth of freshwater dinoflagellates such as Ceratium hirundinella, Peridinium cinctum, and Peridiniopsis elpatiewskyi, which reduce the quality of drinking water in the Zayandeh Rud Reservoir. To this end, 152 algal and zoological samples were collected from the reservoir located in the Central part of Iran in January, April, July, and October 2011. Abiotic factors such as pH, temperature, conductivity, transparency, dissolved oxygen, and nutrient concentration of the water were measured in all study stations. The results showed that the population dynamics of dinoflagellates in the Zayandeh Rud Reservoir was different depending on season, station, and depth. The findings proved that C. hirundinella was one of the dominant autumn planktons in the highest biovolume in the Zayandeh Rud Reservoir. While P. elpatiewskyi was present in the reservoir throughout a year with biovolume peak in summer. Accompanying bloom of P. elpatiewskyi and C. hirundinella, P. cinctum also grew in well-heated summer and autumn waters. It was further found that Ceratium density was positively correlated with sulfate ion concentrations, while the growth of P. cinctum and P. elpatiewskyi were associated, first and foremost, with NO2− and Mn.

Evaluación del fitoplancton en el embalse Escaba (Tucumán – Argentina) para caracterizar la calidad de sus aguas

El objetivo de este trabajo es analizar las variaciones espacio-temporales del fitoplancton de la zona limnética del embalse Escaba y la desembocadura de sus tributarios: ríos Chavarría, Las Moras, El Chorro y Singuil, respecto a variables fisicoquímicas para caracterizar la calidad del agua durante 2010-2012. Se determinaron 135 taxones: Bacillariophyceae (77), Chlorophyta (40), Cyanophyta (12), Euglenophyta (5) y Dinophyta (1). La densidad algal varió de 84 a 6924 ind/ml y Ceratium hirundinella fue dominante excepto en primavera de 2011. La clorofila a tuvo un rango variable a nivel temporal y espacial fluctuando entre 6 y 2511 ?g/l, encontrándose mayores registros en los5afluentes. Los elevados valores de biomasa y la caracterización polisapróbica de sus aguas determinaron un estado ecológico deficiente o malo. La diversidad específica osciló entre 0-2,76. El modelo lineal generalizado detectó cambios en las abundancias de C. hirundinella entre las dos temporadas, sitios y meses acompañados por diferencias en algunas variables fisicoquímicas (amonio, OD y DBO5) Sólo se observó durante noviembre de 2011 una relación inversa entre la densidad del dinoflagelado con el amonio. Este trabajo aportó al conocimiento de la biodiversidad algal del embalse Escaba y amplió la distribución de C. hirundinella en la provincia de Tucumán.

The impact of zeta potential changes on Ceratium hirundinella cell removal and the ability of cells to restore its natural surface charge during drinking water purification

The removal efficacy ofCeratiumcells from source water was evaluated. The best ZP for coagulation were achieved with organic polymer and Ca(OH)2. Cells were able to restore their ZP after 120 and 240 minutes settling time.

Physical and chemical impacts of conventional unit processes and coagulants on the dinoflagellate, Ceratium hirundinella

The freshwater dinoflagellate, Ceratium hirundinella (C. hirundinella) with its complex morphology and robust thecal plate cell covering, is responsible for extensive problems during drinking water production. To have a better understanding of these problems, knowledge of what happens to the integrity of the cells after each step of the conventional water treatment process is essential. Therefore, the aim of this study was to investigate the physical and chemical impacts of conventional unit processes (prior to sand filtration) on the morphology of C. hirundinella cells and the appearance of cells in aggregation or in flocs. Source water samples enriched with C. hirundinella cells (>500 cells/ml) were used to conduct jar stirring experiments. Samples for scanning electron microscopy (SEM) were collected from raw water, after flash mixing and from the sediment that formed when dosing various coagulant chemicals. The coagulant options included hydrated lime and activated silica (Ca(OH)2-SiO2) which increase the pH to levels above 10, hydrated lime in combination with organic polymer (Ca(OH)2-poly) that increases the pH to levels of approximately 9 and organic polymer (poly) alone which has no effect on the pH of the water. Results obtained from SEM investigations revealed significant damage to the cells due to flash mixing, as well as due to the dosing of Ca(OH)2-SiO2. When dosing organic polymer alone, no further impacts on the cell integrity were observed after flash mixing, but it resulted in poor cell removal. Ca(OH)2-poly caused less damaging effects to the cells when compared to Ca(OH)2-SiO2, but resulted in moderate removal of C. hirundinella cells. Treatment plants that experience algal-related problems, especially during coagulation should consider using SEM to select appropriate coagulant dosages in order to avoid further cell damage that may occur during floc formation.

Variación estacional del zooplancton del embalse Ignacio Allende, Guanajuato, México y su relación con el fitoplancton y factores ambientales

Se estudiaron las comunidades planctónicas y los factores ambientales del embalse Ignacio Allende de julio de 1990 a junio de 1991. Se presentó una proliferación de ciaIlofíceas ell el verano coincidente con el mayor nivel de agua, seguido por la dominacia de bacilariofíceas ell los meses mos, en primavera con el incremento en la temperatura las cJoroficeas alcanzaron sus mayores densidades. Las dinofíceas y euglenofíceas presentaron la menor riqueza específica. La proliferación de Anabaena variabilis en el verano y la alta frecuencia de Ceratium hirundinella, Aufacosseira granulara y FragUaria crolonensis se asocian con cuerpos de agua tropicales eutróficos. Se encontraron 39 taxones zooplanctónicos, de los cuales Diaphanosoma birgei. 80smina fongirostris, Daphnia parvula, Diaptomus (Mastigodiaptomus) montezumae, Acanthocyclops vemalis, Kerate[ la cochlearis, Polyarthra vulgaris y Asplanchna priodonta, fueron persistentes en todo el ciclo. Un análisis de correspondencias canónicas mostró las relaciones que guardan los cambios en composición del zooplancton con las características físicas y químicas del embals