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Laboratory Flume Investigation Into Hydrodynamic Properties Of Select Stalk Forming Diatom Morphologies, Joshua G. Stepanek

Culminating Projects in Biology

Cell outline has been used as the principle metric for taxon recognition in diatoms, a single celled aquatic primary producer. This investigation examines the fluid dynamic implications of three stalk forming diatom outlines. This was accomplished by examining large scale shape differences between the gomphonemoid taxa Gomphoneis herculeana, and the Cymbelloid taxa Cymbella mexicana, as well as small morphological changes to the diatom Gomphonema acuminatum. Fluid dynamic investigations of microscopic diatoms were made possible through the production of scale models of selected diatoms using an atomic force microscope and 3-D rapid prototype printer, flows around these models were quantified through …

The Effects Of The Pre-Emergence Herbicides Chloramben, Atrazine, And Alachlor On Growth And Development Of Leopard Frog, Rana Pipiens (Schreber), Larvae, Dean L. Hovey

Culminating Projects in Biology

Groups of 20 Rana pipiens larvae were exposed to Atrazine, Chloramben, or Alachlor in a 96-hour, static bioassay. Threshold lethal concentrations of 8.5 ppm and 250 ppm were determined for Atrazine and Chloramben, respectively, for larvae at Taylor-Kollros Stage I. The threshold lethal concentration of Alachlor was 1.5 ppm for larvae at Taylor-Kollros Stage III.

Determinations of growth inhibition, group variability, and examinations for external abnormalities were made 40 days after the termination of the 96-hour exposures at the lethal thresholds of Atrazine and Chloramben.

Atrazine and Chloramben did not significantly inhibit growth under those conditions, but did induce a …