Variation of Aulacoseira Granulata As An Eco-Pollution Indicator In Sub-Tropical Large River Ganga In India: A Multivariate Analytical Approach

Aulacoseira granulata (Ehrenberg) Simonsen 1979 is one of the major ecological indicators of the water quality of lotic as well as lentic aquatic ecosystems. To assess major environmental factors contributor to A.granulata bloom in the riverine system, a study was carried out from 2018 to 2019 comprising four different seasons at 11 sampling sites of river Ganga in the middle and lower stretch of river Ganga comprising freshwater and estuarine zones. For the analysis, different univariate, as well as multivariate analytical tools such as Principal Component Analysis (PCA) and Water pollution Index (WPI), were used. In the finding, it was observed that the average abundance of Aulacoseira granulata was found maximum during the winter season. Among all the studied sites, the maximum average abundance was at Balagarh (71576 cell l-1) and minimum at Diamond Harbour (68 cell l-1). The environmental factors such as dissolved oxygen, depth, and altitude showed a positive and water temperature negatively influencing the growth rate of A. granulate. WPI showed a significantly negative correlation with cell length. Finally, the study concludes that the blooming of Aulacoseira granulata is highly influenced by varied environmental conditions along the river Ganga suggesting possible eutrophication. Therefore, a certain minimum flow and depth especially during the lean season have to be maintained for the sustenance of planktonic biota in the river Ganga.

Monitoramento do fitoplâncton na água bruta da ETA Macapá e inferências sobre a covid-19

O fitoplâncton é formado por microalgas e cianobactérias, fornecedores de oxigênio para o meio aquático. Em ecossistemas desequilibrados esses organismos podem se multiplicar e produzir toxinas que afetam a saúde humana e animal. Este estudo teve como objetivo identificar padrões de densidade no fitoplâncton da água bruta da ETAm e relacionar a influência de fatores físicos, químicos e ambientais sobre a densidade das espécies. As amostragens foram realizadas entre maio de 2019 e agosto de 2020 (exceto em março-maio/2020, devido ao isolamento social). Foram identificados 86 táxons: Bacillariophyta (45), Cyanophyta (18), Chlorophyta (10), Charophyta (10), Dinophyta (1), Euglenophyta (1) e Rhodophyta (1), sendo as cianobactérias e diatomáceas os grupos mais abundantes. E as espécies mais abundantes foram Aulacoseira granulata e Limnothrix planctonica, respectivamente. Em relação à densidade de cianobactérias, observou-se que há padrão de aumento no período maio-agosto similar aos anos anteriores (2015-2016). Porém a densidade de cianobactérias observada neste estudo em 2019 (7083,2 cels. mL-1) foi 7x maior que em anos anteriores (1090 cels.mL-1 em 2015), todavia ainda estão em conformidade com os padrões estabelecidos pelo Ministério da Saúde (<10.000 cels.mL-1). Em junho e julho de 2020, quando era esperado o pico de cianobactérias, ocorreu queda expressiva na densidade. Pode-se inferir que isto ocorreu pela relação entre o aumento do isolamento social em Macapá e a diminuição da abundância de cianobactérias observada neste período de 2020 (R2= 0,94). Quanto à influência dos parâmetros ambientais, a transparência da água foi o parâmetro com maior influência na densidade de cianobactérias.

Composicion algal y bioindicadores de calidad de agua. Caso de estudio: Embalse San Roque, Córdoba. Argentina

El embalse San Roque se encuentra a 11 km de la ciudad de Carlos Paz y a 40 de la ciudad de Córdoba y una de las funciones es brindar agua a gran parte de la ciudad y sus alrededores. Debido a que recibe un alto aporte de nutrientes provenientes principalmente de la actividad antrópica constituye un ecosistema favorable para el desarrollo de comunidades algales. El objetivo general del trabajo fue evaluar el estado trófico del embalse a través de índices de eutrofización e indicadores biológicos. Se llevaron a cabo muestreos estacionales desde febrero de 2014 hasta febrero de 2016, en el muro de cierre de embalse y la desembocadura de los tributarios. Se midieron parámetros físicos y químicos y determinaron nutrientes. Se realizó la identificación taxonómica de las especies, se calculó la biomasa fitoplanctónica mediante el biovolumen y clorofila a y se estimó el índice de estado trófico. Se determinaron un total de 204 Taxa. El componente dominante del fitoplancton fue el dinoflagelado Ceratium furcoides y como subdominante la diatomea Aulacoseira granulata. De acuerdo al índice de estado trófico ubicamos al embalse San Roque en estado eutrófico, condiciones indeseables en un ambiente utilizado para provisión de agua potable.

Morphology and taxonomy of Aulacoseira muzzanensis (Bacillariophyta)

Morphological investigation of wild populations of Aulacoseira granulata shows significant variability of its quantitative morphological characteristics: valve diameter and height; number of rows of areolae and number of areolae in 10 μm on the valve mantle; and number of spines and their length on separation valves. Low values of mantle height to valve diameter ratio and large numbers of areolae in 10 μm, typical for A. muzzanensis, are also found in populations of A. granulata. The valve height/diameter ratio decreases as the valve diameter increases, and such relationships also occur in other taxa of this genus (A. baicalensis, A. islandica, and A. subarctica). No correlation is found between valve diameter and number of spines in separation valves. Our investigations confirm the correctness of referring A. muzzanensis to the synonymy of A. granulata, and based on original and published data, we suggest emendation of the diagnosis of A. granulata.

Nanoporous Silica of Some Egyptian Diatom Frustules as a Promising Natural Material

Background: Diatoms are a large unique group of unicellular microalgae with a significant ornamented cell wall made of hydrated silica, which is called "frustule". Their ornamented siliceous shells are usually composed of multi-layer structures with multi-scale porosity, which can be used as a promising source to obtain hierarchical macro and mesoporous silica microparticles. The present study is one step forward through a long road seeking for green nanofabrication techniques of such porous materials that will be economically more efficient with large design flexibility. Materials and Methods: For seeking different porosity scales, architectures, and distribution patterns, a total of 237 diatom species and varieties belonging to 68 genera were identified from 59 samples, which were collected from different Egyptian habitats and environments. Of these eight species were selected to study their frustules' ultra-structures in details, including; Aulacoseira granulata (Ehrenberg) Simonsen, Actinocyclus octonarius Ehrenberg, Cyclotella meneghiniana Kützing, Pleurosira laevis (Ehrenberg) Compére, Synedra ulna (Nitzsch) Ehrenberg, Achnanthes brevipes Agardh, Nitzschia amphibia Grunow and Nitzschia palea (Kützing) W. Smith. Nitzschia palea (Kützing) W. Smith was also isolated and cultivated. Results: The ultrastructure and porosity of all studied species had been revealed. The porosity scale was ranged from 5 to 500 nm in diameter. Conclusion: The obtained results showed the potential of diatom frustules in nanotechnology as a source of natural silica microparticles with macro and mesoporous structures could be of a large interest for applications including ultra, micro and nanofiltration, drug delivery systems, optoelectronics, or other novel nanotechnology applications.

PROSPECTING THE FIRST CULTURE COLLECTION OF ALGAE OF THE PERNAMBUCO SEMIARID, BRAZIL

The growing concern about the shortage of fossil fuels drives the search for new sources of sustainable energy. Microalgae are considered promising in this area, since they are sources of third generation biofuels and protein. The present study aimed at describing and isolating species from the native phytoplankton communities of four reservoirs in the Pernambuco semiarid, making them available for experiments that can evaluate the biotechnological potential and meet the demands of the region. The collections occurred in water bodies located in the Pernambuco semiarid and the identification of the taxa occurred based on morphological characters using specific literature. A total of twenty-one taxa were identified, eight of them Cyanophyceae (Anabaena sp., Aphanocapsa elachista, Chroococcus dispersus, Dolichospermum sp., Merismopedia sp., Microcystis aeruginosa, Pseudanabaena limnetica, Synechococcus sp.), ten Chlorophyceae (Chlorella sp., Cosmarium bioculatum, Desmodesmus spp., Dictyosphaerium sp., Pediastrum duplex, Pediastrum simplex, Pseudokirchineriella subcapitata, Scenedesmus sp., Staurastrum leptocladum, Trochiscia sp) and only one of the following classes Bacillariophyceae (Aulacoseira granulata), Euglenophyceae (Trachelomonas volvocida) and Dinophyceae (Ceratium furcoides). The bioprospection of microalgae in the semiarid region of Pernambuco has made possible the formation of a bank of strains, important for fictional studies and obtaining biomass of species with biotechnological potential.

Holocene environmental change in Tonle Sap, Cambodia based on fossil diatoms

Tonle Sap Lake (“Great Lake”, Cambodia) is a biggest inland freshwater body. The size of the lake is changed dynamically following monsoon via connected to the Mekong river, especially the flood pulse. The flood pulse on Tonle Sap has affected considerably the lake’s ecological property as well diatom assemblages. The present study aimed to assess the impact of the flood pulse to diatom assemblages by time. Two short sediment cores from Tonle Sap Lake with the depth of 1.54 m and 1.27 m respectively below the lake floor were collected in May 2013 and 2015 and one short sediment core with the depth of 1.68 m was collected from the confluence of the Mekong River and Tonle Sap River in May, 2013. The sedimentations were dated by using radiometric dating (210Pb and 137Cs). Succession of fossil diatom assemblages was calculated by Rarefaction index (ES) and species richness is by Hill's N2 index. A total of 70 diatom species was released, and the diversity of diatom assemblages was extremely fluctuated in function of time (p-value = 0.0045***). Especially, 6 diatom taxa: Aulacoseira distans, Aulacoseira granulata, Aulacoseira granulata var. angustissima, Gyrosigma acuminatum, Gyrosigma attenuatum and Paralia sulcata characterized by the highest relative abundance (>1 %). In term of ecology, these species are the epipelic diatoms living commonly in eutrophication and high suspendid solid conditions. In fact, it is clear that the onset of flood pulses affected considerably the studied diatom assemblages in particular, and made sense to bio-community in general; also the lacustrine environment of Tonle Sap lake was changed very strongly in response to this shift of hydrological regime.

Short-term changes in phytoplankton assemblages and their potential for heavy metal bioaccumulation – a laboratory study

This study focused on phytoplankton changes in polluted waters of Lake Manzala and the assessment of heavy metal bioaccumulation capacity during the 15-day laboratory experiment. Phytoplankton samples were analyzed every day and the concentration of zinc, iron and lead in water, in phytoplankton and in filtrate – every fifth day of the experiment. Significantly higher phytoplankton abundance was recorded in water from the El-Boom station (basin I) compared to the New Bahr El-Baqar drain (basin II), followed by distinct differences in its composition and chlorophyll content. However, the most abundant species were the same in both basins, i.e. Chroococcus minor, Microcystis aeruginosa, Actinoptychus octonarius, Aulacoseira granulata, Pantocsekiella ocellata, Kirchneriella obesa and Nephrocytium limneticum. Water in basin I was more polluted with heavy metals compared to basin II. Basin I was characterized by the dominance of cyanobacteria and high relative abundance of chlorophytes compared to basin II, where either cyanobacteria and/or diatoms dominated in the phytoplankton. In the former basin, the highest uptake factors (UFs) were recorded for iron and zinc and the lowest UF for lead. In basin II, the highest UF was determined for zinc, but relatively high UFs were recorded also for iron and lead. The presented results suggest that phytoplankton can contribute to natural biosorbents of heavy metals in Egyptian lakes.