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Geology topics

Nancy C. Nelson

Publications and source records attributed to Nancy C. Nelson.

3 recordsLinked to original sources
USGS1979

Potentials and limits for the use of ozone as a fish disease control agent

Ozone and chlorine inactivation curves were determined in three types of freshwater at 20 C for the destruction of the fish pathogens Aeromonas salmonicida the etiologic agent of furunculosis, and Yersinia ruckeri the enteric redmouth bacterium (ERM). Ozone and chlorine inactivation curves were also obtained in the same water types at 10 C for the fish pathogenic viruses infectious hematopoietic necrosis (IHNV), and infectious pancreatic necrosis (IPNV). Acute toxicity tests using the rainbow trout as a representative salmonid revealed that ozone was highly toxic at the dose levels used. Partial chronic (3. mo.) testing revealed that ozone exposure at 2 μg/L causes only minimal physiological changes, none of which would be expected to compromise biological function.

Ozone: Science and Engineering↗
USGS1977

Survival of two bacterial fish pathogens (Aeromonas salmonicida and the Enteric Redmouth Bacterium) in ozonated, chlorinated, and untreated waters

Ozone and chlorine inactivation curves were determined in three water types at 20 °C for the destruction of the fish pathogens Aeromonas salmonicida , the etiologic agent of furunculosis, and the enteric redmouth bacterium (ERM). In phosphate-buffered distilled water, 0.01 mg/ℓ ozone inactivated 10 3 cells/ml of ERM and A . salmonicida in 1/2 and 10 min, respectively. Chlorine at this concentration had little effect on either pathogen and a residual of at least 0.05 mg/ℓ was needed to achieve a complete kill within a 10-min contact time. In soft lake water (30 mg/ℓ as CaCO 3 ) a chlorine residual of 0.1 mg/ℓ rapidly inactivated A . salmonicida and ERM but in hard water (120 mg/ℓ) A . salmonicida was more resistant and 0.2 mg/ℓ chlorine was required. Ozonation of the two lake waters at 90 mg O 3 ∙h −1 ∙ℓ −1 (equivalent to a 0.01 mg/ℓ residual in ozone demand-free water) was required to destroy both pathogens within 10 min.In untreated soft lake water 10 3 cells/ml of A . salmonicida survived only 2 days, while the ERM bacterium (10 3 cells/ml) survived even after 20 day s in soft and hard untreated lake waters.

Journal of the Fisheries Research Board of Canada↗
USGS1975

Statistical methods for estimating normal blood chemistry ranges and variance in rainbow trout (Salmo gairdneri), Shasta Strain

Gaussian and nonparametric (percentile estimate and tolerance interval) statistical methods were used to estimate normal ranges for blood chemistry (bicarbonate, bilirubin, calcium, hematocrit, hemoglobin, magnesium, mean cell hemoglobin concentration, osmolality, inorganic phosphorus, and pH for juvenile rainbow ( Salmo gairdneri , Shasta strain) trout held under defined environmental conditions. The percentile estimate and Gaussian methods gave similar normal ranges, whereas the tolerance interval method gave consistently wider ranges for all blood variables except hemoglobin. If the underlying frequency distribution is unknown, the percentile estimate procedure would be the method of choice.

Journal of the Fisheries Research Board of Canada↗