scholarly journals The first floristic study of freshwater dinoflagellates (Dinophyceae) in Colombia

2021 ◽  
Author(s):  
Carolina Bustamante-Gil ◽  
Eduardo Amat ◽  
Andrés Boltovskoy ◽  
John J. Ramírez-Restrepo
Keyword(s):  
Environmental Variables ◽  
Water Systems ◽  
Water Bodies ◽  
Tropical Water ◽  
Floristic Study ◽  
Ecological Aspects ◽  
Apparent Color ◽  
Physical And Chemical Variables ◽  
Physical And Chemical ◽  
Comprehensive Study

The first comprehensive study of dinoflagellate flora and their related environmental variables in reservoirs, swamps, and an insular lake of Colombia is presented. Fourteen Colombian water bodies were assessed. In each, water temperature, electric conductivity, oxygen saturation, turbidity, and apparent color were the physical and chemical variables measured. Twelve dinoflagellate taxa were recorded, indicating a considerable richness compared to similar surveys. Ensembles recovered showed a spatial structuration mediated by the type of the water bodies (reservoirs and swamps); environmental variables and species richness explained equally the differences among the water bodies. The dinoflagellate flora showed altitudinal segregation, with intermediate altitude systems displaying the highest richness values. A brief discussion about the geographical distribution of the species collected is offered. The study contributes to the knowledge of the ecological aspects of dinoflagellate flora and outlines preliminary biodiversity tendencies of ensembles in tropical water systems.

scholarly journals Mangrove oyster (Crassostrea rhizophorae) (Guilding, 1928) farming areas as artificial reefs for fish: A case study in the State of Ceará, Brazil

2006 ◽  
Vol 54 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Luiz Eduardo Lima de Freitas ◽  
Caroline Vieira Feitosa ◽  
Maria Elisabeth de Araújo
Keyword(s):  
Water Quality ◽  
Artificial Reefs ◽  
Visual Census ◽  
Ecological Aspects ◽  
Physical And Chemical Variables ◽  
Crassostrea Rhizophorae ◽  
Tidal Variations ◽  
Physical And Chemical ◽  
Permanent Residents

A type of platform, known as a table, is now being used for mangrove oyster farming. In Fortim, Ceará, Brazil, this activity was begun in June 2000 and covers an area of 50 m² overlying a sand-clay substrate. The present study has the following main objectives: to identify and catalogue the ichthyofauna colonizing the Crassostrea rhizophorae farming platforms; to evaluate ecological aspects, such as the possible correlation between the physical and chemical variables for water quality and the occurrence of the ichthyofauna; and to observe the differences in the fish species found during tidal variations. Specimens were identified and quantified using the linear-transect, visual census methodology. The ichthyofauna observed comprised 3,030 individuals belonging to 28 species and 20 families. Of the 28 species found in the area studied, 14 were marine transients, 12 marine dependent, and only 2 permanent residents. A significant association was observed between the abundance of 11 species and the physical and chemical variables studied. Based on these results, it may be concluded that the platforms act as artificial reefs for the ichthyofauna, being colonized by at least 28 species, and providing protection from predators as well as a source of food and a reproductive substrate.

scholarly journals Invasion of the dinoflagellate Ceratium furcoides (Levander) Langhans 1925 at tropical reservoir and its relation to environmental variables

2012 ◽  
Vol 12 (2) ◽  
pp. 93-100 ◽  
Author(s):  
Lidiane Cristina da Silva ◽  
Isabela Carnielli Leone ◽  
Maria José dos Santos-Wisniewski ◽  
Alberto Carvalho Peret ◽  
Odete Rocha
Keyword(s):  
Environmental Variables ◽  
Rio Grande ◽  
Domestic Sewage ◽  
Tropical Reservoir ◽  
Reservoir Water ◽  
Rio Grande Basin ◽  
Physical And Chemical Variables ◽  
Nitrate And Nitrite ◽  
Physical And Chemical ◽  
Plankton Communities

Dinoflagellates of the genus Ceratium are chiefly marine but there are rare occurrences in freshwater. In this study we analyze the invasion and progressive establishment of Ceratium furcoides, an exotic species, in the Furnas Reservoir. Samples were taken at 36 points in the reservoir, during the months of March, June, September and December, 2007. Measurements of some physical and chemical variables were simultaneously performed at each site. The occurrence of C. furcoides was registered at 20 sites, with densities varying between 0.57 and 28,564,913.0 ind.m-3. Blooms of this species were recorded in points which were classified as mesotrophic, coinciding with the places receiving high amounts of untreated domestic sewage. C. furcoides density was correlated with temperature, nutrients (nitrate and nitrite) and water electric conductivity. The highest density was recorded in June when temperature was low. The presence of Ceratium furcoides in the reservoir apparently has not yet affected the reservoir water quality or other plankton communities. However, if it becomes fully established it could perhaps become a problem in the reservoir or even to spread out to other reservoirs in Rio Grande basin.

scholarly journals INFLUENCE OF THE HYDROLOGICAL CYCLE ON PHYSICAL AND CHEMICAL VARIABLES OF WATER BODIES IN THE VÁRZEA AREAS OF THE MIDDLE SOLIMÕES RIVER REGION (AMAZONAS, BRAZIL)

2014 ◽  
Vol 9 (2) ◽  
pp. 75-90 ◽  
Author(s):  
Joao Paulo Borges Pedro ◽  
Maria Cecília Rosinski Lima Gomes ◽  
Márcia Emília De Jesus Trindade ◽  
Danielle Pedrociane Cavalcante ◽  
Jonas Alves de Oliveira ◽  
...  
Keyword(s):  
Hydrological Cycle ◽  
Water Bodies ◽  
River Region ◽  
Physical And Chemical Variables ◽  
Physical And Chemical ◽  
Solimões River

scholarly journals Tilapia rendalli increases phytoplankton biomass of a shallow tropical lake

2014 ◽  
Vol 26 (4) ◽  
pp. 429-441 ◽  
Author(s):  
Lúcia Helena Sampaio da Silva ◽  
Marlene Sofia Arcifa ◽  
Gian Salazar-Torres ◽  
Vera Lúcia de Moraes Huszar
Keyword(s):  
Treatment Group ◽  
Phytoplankton Biomass ◽  
Experimental Period ◽  
Control Group ◽  
Filter Feeding ◽  
Tropical Reservoir ◽  
Tropical Water ◽  
Tilapia Rendalli ◽  
Physical And Chemical Variables ◽  
Physical And Chemical

AIM: This study aimed to experimentally test the influence of a planktivorous filter-feeding fish (Tilapia rendalli) on the phytoplankton dynamics of a small and shallow tropical reservoir (Lake Monte Alegre, Brazil). Adults of T. rendalli of this lake feed preferentially on phytoplankton, and we hypothesize that: I) adults of T. rendalli will decrease the phytoplankton biomass and composition through direct herbivory, and II) as it is a eutrophic system, fish would not have strong influence on phytoplankton through nutrient cycling. METHODS: To evaluate these different effects on algae, a field experiment was performed in the summer period for 15 days, in mesocosms isolated from the sediment, using a control group (no fish) and a treatment group (with one fish in each mesocosm). Physical and chemical variables and phyto- and zooplankton were evaluated at the start, middle, and end of the experiment. RESULTS: At the end of the experiment, it was observed a significant increase in ammonium concentrations and total phytoplankton biomass, Cyanobacteria and Zygnemaphyceae and all size classes except class II (20-30 µm) in the treatment group (with fish). The biomass increase of the potentially toxic cyanobacterium Cylindrospermospsis raciborskii was also observed in the fish treatment at the end of the experimental period. CONCLUSION: This study did not support both initial hypotheses. It supports the assertion that in tropical water bodies, with similar characteristics to the environment studied, planktivorous filter-feeding fish, such as T. rendalli, are not effective in reducing phytoplankton biomass through direct grazing, even when phytoplankton is one of their main food items. T. rendalli can contribute to the increase of phytoplankton biomass and can promote or increase the eutrophication of aquatic systems.

Morphology and Topology of Coherent Scattering Regions of the Fe-Mn-C Steel Fine Structure

2015 ◽  
Vol 1085 ◽  
pp. 84-90
Author(s):  
Anna P. Zykova ◽  
Irina Kurzina ◽  
Mihail Yu. Novomejsky ◽  
Yuriy D. Novomejsky
Keyword(s):  
Fine Structure ◽  
Hyperfine Structure ◽  
Coherent Scattering ◽  
Technological Properties ◽  
Material Microstructure ◽  
And Topology ◽  
Interaction Of Components ◽  
Physical And Chemical ◽  
Comprehensive Study

The interaction of components in modifying mixtures with the elements of Fe-Mn-С alloys hyperfine structure is investigated. Comprehensive study of the modified material microstructure is conducted. The substructure of Fe-Mn-С alloys is shown to undergo significant changes. The produced castings are characterized with enhanced physical-and-chemical and technological properties

scholarly journals Limnological study of Piraquara river (Upper Iguaçu basin): spatiotemporal variation of physical and chemical variables and watershed zoning

2003 ◽  
Vol 46 (3) ◽  
pp. 383-394 ◽  
Author(s):  
Paulo Henrique C. Marques ◽  
Haydée Torres de Oliveira ◽  
Eunice da Costa Machado
Keyword(s):  
River Basin ◽  
Oxygen Demand ◽  
Principal Component ◽  
Serra Do Mar ◽  
Spatial Gradients ◽  
Water Composition ◽  
Physical And Chemical Variables ◽  
Nitrite Nitrate ◽  
Physical And Chemical ◽  
Iguaçu River

The Piraquara river basin (Upper Iguaçu River basin - Brazil) was studied as an ecological system throughout a complete seasonal cycle, comprising the rainy and dry season. Analyzes of 16 physical and chemical water variables (dissolved oxygen, biochemical oxygen demand, temperature, pH, conductivity, total nitrogen, total phosphorus, ortophosphates, nitrite, nitrate, ammonium, reagent silicate, total suspended solids, chlorophyll - a, flow velocity and depth) showed correlations between water composition and watershed physiographic features, and the Principal Component Analysis allowed to evidence spatial gradients and seasonal differences. The sampling points were clustered in patches with homogeneous behavior, according to ecologycal concepts: patch 1, with strong influence of Serra do Mar mountains; patch 2, medium course, under Piraquara Dam influence and patch 3, under wetlands influence. Two main factors of serial discontinuity were identified: the Piraquara dam effect and the influence of wetlands. The watershed zoning based on limnological characteristics seeks to subsidize research and biomonitoring for this public springs area.

scholarly journals Water quality and potamoplankton evaluation of the Nile River in Upper Egypt

2015 ◽  
Vol 27 (2) ◽  
pp. 171-190 ◽  
Author(s):  
Ahmed Mohamed El-Otify ◽  
Isaac Agaiby Iskaros
Keyword(s):  
Community Structure ◽  
Zooplankton Community ◽  
Water Level Fluctuations ◽  
Main Stream ◽  
Upper Egypt ◽  
Physical And Chemical Variables ◽  
Different Seasons ◽  
High Current Velocity ◽  
Major Nutrients ◽  
Physical And Chemical

Aim: The composition, abundance, community structure of potamoplankton and major physical and chemical variables of the Nile water in Upper Egypt were investigated to assess its status in different seasons during 2007.MethodsWater samples were collected seasonally during 2007 from six investigated sites from variable depths at levels of 0, 2.5 and 5 m. The area of this investigation is defined as the southern 120 Km of the main stream of the Nile in Upper Egypt (24° 04’ – 25° 00’ latitudes and 32° 51’ – 32° 54’ longitudes), downstream of Aswan Old Dam.ResultsAltogether, 121 potamoplankton species, of which 85 related to phytoplankton and 36 appertaining to zooplankton were recorded. Most numerous phytoplankton were Chlorophyceae (42 species) followed by Bacillariophyceae (30 species). Cyanobacteria and Dinophyceae were less numerous with only 11 and 2 species, respectively. Zooplankton species were mainly belonging to three systematic groups namely; Rotifera (24 species), Copepoda (3 species) and Cladocera (9 species). Besides, other rare zooplankton including Platyhelminthes, Nemata and Ciliophora were sparsely encountered. The main hydrological conditions characterizing the investigated area include water level fluctuations (˂82 - ˃85 m above sea level), relatively high current velocity (0.8 - 1.3 m sec–1) and disposal of wastewater. Plankton populations were variably but rather weakly dependent on the major nutrients due to their excessive availability in accessible form for uptake by the producers. For phytoplankton, the community structure was categorized in relation to temperature, pH, SO42– and Mg2+. For zooplankton, the community structure was categorized in relation to conductivity as well as Mg2+. Sampling intervals were inadequate to demonstrate the existing successional pattern of the Nile potamoplankton community. Alterations in the phytoplankton community structure accompanied changes in water temperature represented by the alternate dominance between diatoms and cyanobacteria, while zooplankton community was always dominated by rotifers. Phytoplankton populations were numerically more abundant in autumn and zooplankton peaked in spring.ConclusionsWastewater disposal restricted the abundance of the Nile zooplankton assemblages mainly due to the numerical decline of Rotifera and Cladocera. Otherwise, wastewater did not exert major limits for phytoplankton. The data obtained in this investigation will be crucial to understand potamoplankton regulation and contribute to the knowledge regarding the Limnology of the Nile basin.

scholarly journals Phytoplankton abundance, dominance and coexistence in an eutrophic reservoir in the state of Pernambuco, Northeast Brazil

2011 ◽  
Vol 83 (4) ◽  
pp. 1313-1326 ◽  
Author(s):  
Giulliari A. S. T. Lira ◽  
Elcida L. Araújo ◽  
Maria Do Carmo Bittencourt-Oliveira ◽  
Ariadne N. Moura
Keyword(s):  
Rainy Season ◽  
Phytoplankton Community ◽  
Dry Season ◽  
Cylindrospermopsis Raciborskii ◽  
Phytoplankton Abundance ◽  
Vertical Variation ◽  
Total Phytoplankton ◽  
Physical And Chemical Variables ◽  
Different Depths ◽  
Physical And Chemical

The present study reports the phytoplankton abundance, dominance and co-existence relationships in the eutrophic Carpina reservoir, Pernambuco, Brazil. Sampling was carried out at six different depths bimonthly at a single reservoir spanning two climatic periods: dry season (January, September, and November 2006) and rainy season (March, May, and July 2006). Density, abundance, dominance, specific diversity and equitability of the community were determined, along with chlorophyll a, and physical and chemical variables of the environment. Eight species were considered abundant, and their densities corresponded to more than 90% of the total phytoplankton community quantified. Cyanobacteria represented more than 80% of this density. Cylindrospermopsis raciborskii was the only dominant taxon in the dry season, and was co-dominant in the rainy season. C. raciborskii, Planktothrix agardhii and Geitlerinema amphibium had the greatest densities and lowest vertical variation coefficients. The statistical analysis indicated relationships with vertical and seasonal variations in the phytoplankton community and the following variables: total dissolved solids, water temperature, electrical conductivity and pH. The changes in the environmental variables were discrete and regulated by the establishment of precipitation however, they were able to promote vertical and seasonal instability in the structure of the phytoplankton community.

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