Daphnids
Mostrando 1-5 de 5 artigos, teses e dissertações.
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1. Toxicity evaluation of Microcystis aeruginosa cultures and natural cyanobacteria blooms from reservoirs of Tietê river, SP / Avaliação da toxicidade de Microcystis aeruginosa e de florações naturais de cianobactérias de reservatórios do rio Tietê, SP
The effects of cyanobacteria upon aquatic organisms were evaluated, aiming to characterize and quantify the toxins of both, a monospecific cyanobacterial culture and material from natural blooms occurring in the reservoirs of Tietê river, SP. The already known toxic strain NPLJ-4 of Microcystis aeruginosa was cultured in ASM-1 medium at 25 Celsius degrees a
Publicado em: 2007
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2. Selenium deficiency induced by zinc deprivation in a crustacean
For intact daphnids reared in circumstances of controlled trace element exposure, one consequence of insufficient zinc (Zn) is an increased demand on the animal's pool of available selenium (Se). This demand is manifested by the type of cuticle deterioration associated with Se deficiency and by a depression of reproduction. In the presence of 25 parts per bi
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3. Temporal variation, dormancy, and coexistence: A field test of the storage effect
Theoretical models suggest that overlapping generations, in combination with a temporally fluctuating environment, may allow the persistence of competitors that otherwise would not coexist. Despite extensive theoretical development, this “storage effect” hypothesis has received little empirical attention. Herein I present the first explicit mathematical
The National Academy of Sciences of the USA.
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4. Changes in 22Na influx and outflux in Daphnia magna (Straus) as a function of elevated Al concentrations in soft water at low pH
The effects of aluminum (Al) on sodium (Na) regulation by the freshwater crustacean Daphnia magna were determined. 22Na influx and outflux experiments were conducted in soft water adjusted to pH 4.5, 5.0, and 6.5 (reference pH) with either ambient (0.02 mg/liter) or high (1.02 mg/liter) concentrations of total Al. The results indicate that Al toxicity was pH
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5. Relationship between Bacterial Community Composition and Bottom-Up versus Top-Down Variables in Four Eutrophic Shallow Lakes
Bacterial community composition was monitored in four shallow eutrophic lakes during one year using denaturing gradient gel electrophoresis (DGGE) of PCR-amplified prokaryotic rDNA genes. Of the four lakes investigated, two were of the clearwater type and had dense stands of submerged macrophytes while two others were of the turbid type characterized by the
American Society for Microbiology.