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| Registros recuperados: 155 | |
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| Pereira da SILVA,Kelly Dayane; SANTOS,João Paulo de Oliveira; ARAUJO,María Cristina Santos Pereira de; MACHADO,Célia Cristina Clemente; BARBOSA,Luciana Gomes. |
| ABSTRACT Historically, the reduction in water quality has been associated with changes in land use, especially changes in urbanization and expansion of agricultural frontiers. The objective of this study was to understand the characteristics of the diatomological community and the use and occupation of the soil around three reservoirs (Arara, Rio do Canto and Araçagi) and natural lagoon (Lagoa do Paó) (Northeast Brazil). Land use was determined using high spatial resolution satellite images. Abiotic variables of water and total phosphorus, organic matter and diatoms in surface sediments were analyzed. Abiotic variables and assemblages of diatoms were analyzed using Principal Component Analysis (PCA). Four types of land use have been identified, associated... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bacillariophyta; Eutrophication; Geographic information system; Semi-arid zone. |
| Ano: 2022 |
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-548X2022000200249 |
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| POOT-DELGADO,Carlos Antonio; OKOLODKOV,Yuri B.; AKÉ-CASTILLO,José Antolin; RENDÓN von OSTEN.,Jaime. |
| ABSTRACT Cyanobacteria inhabit hypersaline, marine and freshwater environments. Some toxic and non-toxic species can form harmful blooms. The aim of this study was to identify potentially harmful cyanobacterial species in the oyster banks of Términos Lagoon, the southeastern Gulf of Mexico. Six sample sites (up to 2-m depth) were monitored monthly from August 2012 to September 2013. Water temperature, salinity, pH, dissolved oxygen saturation (% DO), inorganic nutrients and abundance of cyanobacteria were determined. Temperature and salinity were characterized by marked seasonal differences (26.8 to 30.6 °C and 6.1 to 19.5, respectively). The pH values (ranging from 7.1 to 8.4) and the % DO (88.4 to 118.2 %) suggest a predominance of photosynthetic... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Annual cycle; Cyanobacteria; Eutrophication; Gulf of Mexico; Harmful algal blooms. |
| Ano: 2018 |
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-548X2018000100051 |
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| Dantas,Ênio Wocyli; Moura,Ariadne do Nascimento; Bittencourt-Oliveira,Maria do Carmo; Arruda Neto,João Dias de Toledo; Cavalcanti,Airlton de Deus C.. |
| The aim of this study was to determine how abiotic factors drive the phytoplankton community in a water supply reservoir within short sampling intervals. Samples were collected at the subsurface (0.1 m) and bottom of limnetic (8 m) and littoral (2 m) zones in both the dry and rainy seasons. The following abiotic variables were analyzed: water temperature, dissolved oxygen, electrical conductivity, total dissolved solids, turbidity, pH, total nitrogen, nitrite, nitrate, total phosphorus, total dissolved phosphorus and orthophosphate. Phytoplankton biomass was determined from biovolume values. The role abiotic variables play in the dynamics of phytoplankton species was determined by means of Canonical Correspondence Analysis. Algae biomass ranged from... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cylindrospermopsis raciborskii; Eutrophication; Nutrients; Water supply reservoir. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062008000400008 |
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| Borburema,Henrique Douglas dos Santos; Lima,Ruth Pessoa de; Miranda,George Emmanuel Cavalcanti de. |
| ABSTRACT Global change and coastal eutrophication are affecting macroalgae worldwide. We analyzed the effects of increased water temperature (25, 28 and 32 °C) and eutrophication on the growth of Bostrychia binderi and Bostrychia montagnei in a range of salinities (18, 24, 30, 36 and 42 PSU) through three independent multifactorial experiments. Both species had higher growth at 25 °C than at 28 and 32 °C (warming scenario projected by IPCC), suggesting a negative effect of ocean warming. The species showed a broad tolerance to the range of salinities tested, with higher growth at 36 and 42 PSU, as a local adaptation strategy. Oligotrophic seawater significantly affected the growth of both species because the lowest growth was found in this condition,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bostrychia; Bostrychietum; Climate change; Ecophysiology; Estuarine macroalgae; Eutrophication; Global change; Growth; Salinity variation; Sea level rise. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062020000400662 |
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| Lima, Paulo de Freitas; Sousa, Mart Som Reis; Porfírio, André Ferreira; Almeida, Beatriz Soares; Freire, Rogério Herlon Furtado; Santaella, Sandra Tédde. |
| The Carlson’s (1977) Trophic State Index (TSI) is a widely employed tool to estimate the degree of eutrophication in a reservoir. In Brazil, the need of a classification system that would take into account regional characteristics employed adjusted indexes generated by data from reservoirs in the southeastern region of the country. Current research compares responses for Carlson’s TSI (1977) and its derivations for Brazilian reservoirs from data collected in the Pereira de Miranda Reservoir (State of Ceará, Brazil), and analyzes the influence of local conditions on results and their applicability to reservoirs in the semiarid region. TSIs were calculated by data on total phosphorus, chlorophyll a and water transparency. The reservoir was estimated as... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ciências biológicas; Ecologia (2.05.00.00-9) hydro-climatic conditions; Eutrophication; Limiting nutrient; Phosphorus; Nitrogen; Chlorophyll a Ecologia de ecossistemas (2.05.02.00-1). |
| Ano: 2015 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciBiolSci/article/view/27160 |
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| Pereira,Luci C.C.; Monteiro,Marcela C.; Guimarães,Danielly O.; Matos,Jislene B.; Costa,Rauquírio M. da. |
| Bragança's socioeconomic situation is highly dependent on estuarine and marine biological resources that are influenced by tidal cycles and climatology. Field measurements (hydrological, hydrodynamic and microbiological variables) were taken in the most urbanized zone from Caeté estuary to characterise the quality of the local environment. During the dry period, the estuary was more eutrophic and presented the highest temperature (30.5 °C in Oct./06), salinity (17 psu in Feb./07), pH (8.24 in Feb./07) and fecal coliform (> 1000 MPN/100 ml in Dec./06 and Feb./07) values. The phytoplankton Cyclotella meneghiniana, Coscinodiscus centralis and other r-strategist species were observed. The lack of basic hydric canalization was responsible for the local... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Equatorial estuary; Temporal variation; Eutrophication; Northern Brazil. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652010000200022 |
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| Silva,Lidiane Cristina da; Leone,Isabela Carnielli; Santos-Wisniewski,Maria José dos; Peret,Alberto Carvalho; Rocha,Odete. |
| 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... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Invasive species; Algal blooms; Eutrophication; Reservoir ecology. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032012000200010 |
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| Faustino,Samantha Borges; Fontana,Luciane; Bartozek,Elaine Cristina Rodrigues; Bicudo,Carlos Eduardo de Mattos; Bicudo,Denise de Campos. |
| Fresh water biodiversity is an increasing concern due to growing human impact. Herein, we report a long-term survey (ca. 90 years) of sedimentary diatoms and the modern flora from surface sediments and their biodiversity changes along a eutrophication gradient. Study was carried out in one of the most important water supply reservoirs (Guarapiranga Reservoir) of São Paulo Metropolitan Region, Brazil. Results are based on 75 core subsamples (subfossil assemblages from core) previously dated by 210Pb and 14 samples from surface sediments (modern assemblages). Overall, 84 taxa were reported, belonging to 30 genera, 71 species and eight non-typical varieties, besides five probable new taxa. Results expanded two new additions for the Brazilian diatom flora... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bacillariophyta; Biodiversity change; Eutrophication; Guarapiranga Reservoir; Paleolimnology; Species richness. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032016000200203 |
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| Siqueira,Adriana; Godinho,Mirna Januária Leal; Kolm,Hedda Elisabeth; Machado,Eunice da Costa. |
| The aim of this wat was to evaluate the water quality in four tidal creeks of Paraná, Brazil, with different anthropic influences. Samples were collected every three months. Temperature, salinity, pH, alkalinity, total CO2, dissolved O2, nitrite, nitrate, N-ammoniacal, phosphate, silicate, particulate suspended matter, humic matter, total chlorophyll, total and fecal coliform bacteria of surface water were measured in each sample and compared. For all the stations water temperature was lower in winter, but ranged within typically subtropical values. Salinity (7 - 25) and pH (7.08 - 7.91) were higher in Perequê tidal creek indicating that only this tidal creek was strongly influenced by the nearby ocean waters. Lower dissolved O2, reaching anoxic levels... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Tidal creek; Eutrophication; Coast of Paraná. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132009000200028 |
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| Marques Júnior,Aguinaldo Nepomuceno; Crapez,Mirian Araujo Carlos; Barboza,Conceição Denise Nunes. |
| The present study aimed to evaluate the water quality of the Icaraí Sewage Outfall (ISEO) area. Sampling was conducted during winter and summer, and water samples were analyzed for dissolved oxygen, pH, temperature, salinity, dissolved inorganic nutrients (DIN), seston, particulate organic matter (POM), and pigments. Results showed that the water chemistry of the area suffers temporal and spatial variation. Great variability was also seen in the C:N:P ratios of POM (August, 112:30:1; December, 59:11:1) and in the DIN concentrations. Chlorophyll-a and ammonium concentrations (4.5 µg L-1 - 71.2 µg L-1, and 0.20 µM - 52,6 µM, respectively) characterized the ISEO area as eutrophic. The dispersal of the material was not effective under certain oceanographic... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Eutrophication; Sewage outfall; Water pollution; Nutrients; Guanabara Bay. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132006000500014 |
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| Santos,Isaac Rodrigues; Costa,Ronaldo Cataldo; Freitas,Ubiratan; Fillmann,Gilberto. |
| The hypothesis that effluents treated through activated sludge process cause changes in nutrient biogeochemistry of receiving water bodies was investigated in Vieira creek, southern Brazil. Dissolved oxygen, suspended matter, and pH did not vary among the sampling stations. Nutrient, biochemical oxygen demand, and conductivity values were significantly higher downstream from the Wastewater Treatment Plant (WWTP) effluents. Further downstream, nitrate concentrations were higher due to ammonium nitrification, organic matter remineralization and/or the occurrence of unidentified sources. Per capita nutrient emission factors were estimated to be 0.16 kg P.yr-1 and 4.14 kg N.yr-1. Under pristine conditions, low N:P ratios were observed, which were significantly... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Activated sludge; Nutrients; Contamination; Coastal zone; Biogeochemistry; Eutrophication. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132008000100019 |
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| Meirelles-Pereira,Frederico de; Pereira,Angela de Meirelles Santos; Silva,Márcio Cataldo Gomes da; Gonçalves,Verônica Dias; Brum,Paulo Roberto; Castro,Almeida Ribeiro de; Pereira,Alexandre Adler; Esteves,Francisco de Assis; Pereira,José Augusto Adler. |
| In view of the intimate relationship of humans with coastal lagoons (used for recreation, tourism, water supply, etc.), the discharge of domestic effluents may lead to the establishment of routes of dissemination of pathogenic microorganisms, including microorganisms carrying genes for resistance to antimicrobials, through the surrounding human communities. The objective of the present investigation was to relate the presence of antimicrobial-resistant bacteria to the environmental characteristics of three coastal lagoons, comparing the results with those from hospital sewage. Of the lagoons evaluated, two (Geribá and Imboassica) receive domestic sewage discharge, and the other (Cabiúnas) is still in a natural state. We isolated in a culture medium... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bacterial resistance; Eutrophication; Sanitary microbiology; Environmental microbiology. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822002000400002 |
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| Registros recuperados: 155 | |
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