Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 34 for “"Daphnia pulex"”.
-
Genetic variation within the Daphnia pulex genome
<p>Genetic variation within the diploid Daphnia pulex genome was examined using a high quality de novo assembly and shotgun reads from two distinct D. pulex clones. Patterns of variation and divergence at single nucleotides were examined in physical and functional regions of the genome using …
-
Thermal Adaptation in <em>Daphnia pulex</em>.
… in freshwater planktonic crustacean <em>Daphnia pulex</em> has been investigated by means of heatshock (35°C) experiments using individuals acclimated to different water temperatures (18, 24, and 28°C). Retention of mobility and survival during the heatshock experiments differed among …
-
Acute and chronic effects of selenium on Daphnia pulex
… All data are expressed as selenite-selenium. Daphnia pulex had a 48 hr LC50 of 3.87 mg/l selenium. The 96 hr LC50 and EC50O values for Gambusia affinis and Physa sp. respectively, were 12.56 and 27.08 mg/l selenium. The sublethal effects of 0.2, 0.4, 0.6 and 0.8 mg/1 selenium on survival, …
-
The consequences of predation by Chaoborus americanus on Daphnia pulex
… larva Chaoborus americanus on the crustacean Daphnia pulex were investigated with a combination of laboratory and field assessments. All approaches indicated that Chaoborus inflict a pattern of size-specific mortality on Daphnia that can be well approximated by a Gaussian function. Maximum …
-
Evolution of asexuality in Daphnia pulex: Implications of mitochondrial-DNA analysis.
A large scale survey of natural populations of Daphnia pulex was undertaken in the spring of 1985. Seventy seven populations were sampled from southwestern Ontario and central Michigan. Clones were also collected from Churchill, Manitoba. Clonal characteristics were determined by protein …
-
The effects of temperature on the sensitivity of Daphnia pulex to two simulated industrial effluents
… on the sensitivity of mixed age adult Daphnia pulex to a simulated cooling tower blowdown and a simulated refinery effluent. In addition, the metabolic rate compensation capability of Daphnia exposed to temperature was determined. An artificial refinery mixture (ARM) simulated the 1977 …
-
Abundance, Standing Stock Biomass and species Composition of Zooplankton in Lake Sakakawea, ND and Uptake of Dissolved Organic Carbon (DOC) by Daphnia pulex
… 4.0 ppm through September 18. To determine if Daphnia pulex utilize DOC as a potential food source, live adult D. pulex were exposed to four levels of radiolabelled DOC (n = 10 each in 5.0, 9.8, 25. 9 and 45.8 ppm DO14C) for 1 hr. As a control, freshly killed daphnids were exposed to the same …
-
The effects of water-soluble fractions of naphthalene, phenanthrene, no. 2 fuel oil, and coal-tar creosote on the freshwater cladoceran, Daphnia pulex
… growth, reproduction, feeding, and metabolism of Daphnia pulex. The 48 hr LC50 values after acute exposure (as percent WSF) for creosote, No. 2 fuel oil, phenanthrene and naphthalene were 2.91, 34.10, >>100, and 57.52 percent, respectively. Gas chromatography analysis indicated naphthalene and …
-
The Behaviour of Daphnia pulex de Geer in a temperature gradient, with special reference to the effect of exposure to D.D.T. upon the selected temperature
The selected temperature of Daphnia pulex de Geer as determined in a horizontal still-water temperature gradient showed no effect of acclimation at 15ºC and 20ºC. Exposure to varying concentrations of the DDT-carrier ethanol resulted in decreases in the selected temperatures to values below that …
-
Food Selectivity of Bigmouth Buffalo (Ictiobus cyprinellus, Valenciennes) in Lake Poinsett, South Dakota
… subadults and adults fed entirely on plankton. Daphnia pulex adults comprised 83.7 to 96.7% of the food items during periods of ice cover (January to April). Daphnia pulex adults and juveniles comprised 68.5% by volume and cyclopoid copepods 29.7%^ of the diet from April to July. Summer (July to …
-
Chemical characterization and aquatic biotoxicity testing of dye wastewaters and their reduction products
… purified compound was measured with Microtox and Daphnia pulex tests. Microtox tests were also performed on compounds with similar structures to p- (2-hydroxyethylsulfone) aniline. Wastewater samples containing textile dye wastes from a Publicly Owned Treatment Works (POTW) that treated textile …
-
Food Selectivity of the Black Bullhead (Ictalurus melas, Rafinesque) in Lake Poinsett, South Dakota
… significant seasonal vairaiton in diet. Daphnia pulex and chronomid larvae were important food items in winter. Bullheads fed primarily on chironomid pupae. Dphnia pulex, and crayfish, in the spring. Fish and Leptodora were the principal organisms consumed in summer and fall. Food …
-
Spatial and Temporal Genetic Heterogeneity in a Natural Daphnia Population: Ecological and Physiological Differences Between Genotypes (Cladocera, Freshwater, Parthenogenesis)
… of the cyclically, parthenogenetic cladoceran, Daphnia pulex, inhabiting a permanent farm pond in east-central Illinois, indicated that electrophoretically distinct genotypes (clones) are frequently distributed non-randomly in the pond, both vertically and horizontally. Spatial autocorrelation …
-
Fate and effects of triallate in a prairie wetland
… for phytoplankton, periphyton, zooplankton (Daphnia pulex) and amphipods (Hyalella azteca). Biomass of phytoplankton and periphyton was not affected by triallate. Daphnia pulex and Hyalella azteca suffered reduced body size and reproduction. However, some of the results were inconsistent …
-
Food, Growth, and Reproduction of White Crappies (Pomixis Annularis) and Black Crappies (P. Nigromaculatus) in Lake Poinsett, South Dakota
… % miscellaneous organisms. Both species selected Daphnia pulex over other zooplankton and probably contributed to its decline from 193.8/l on June 27 to 0.0/1 on August 21. Both species preyed indiscriminately on forage fish. Growth rates were comparable to those found in similar temperate lakes. …
-
Temporal and spatial patterns of abundance of age 0 threadfin shad (Dorosoma petenense) in Overton Arm, Lake Mead
… {dollar}\alpha{dollar} concentrations and Daphnia pulex egg/adult female ratios, were also determined for some stations and dates; There was an apparent link between resource availability and young shad abundance. There was little temporal or spatial variation in mean length. (Abstract …
-
The Aquatic Ecology of Two Seasonal Marshes in Eastern South Dakota
… formed large thick mats by the end of June 1975. Daphnia pulex was the dominant zooplankter in Bothwell Marsh and made up 33% of the zooplankton density during the 1975 season. The population was triacmic, and ephippia formation for the populations of the next wet season occurred during mid-season …
-
The Effects of Diazinon on the Growth Rates and Population Dynamics of Planktonic Algae and the Possible Uptake By Two Algal Species
… A bioassay using Diazinon-exposed algal cells in Daphnia pulex cultures showed that the possible transfer of appreciable amounts of insecticide from algal cells to the Daphnia cultures was predominately responsible for the subsequent mortality rates.
-
Effects of diversity on community assembly dynamics in newly formed pond communities
… on ecologically relevant traits for our focal Daphnia pulex clones originally stocked in the field experiment to determine if performance in the field (ability to persist) was determined by genotype differences and/or phenotypic plasticity in the population growth rate parameter, r. Despite …
Page 1 of 2