Date of Award


Degree Name

Biological Sciences


College of Science

Type of Degree


Document Type


First Advisor

Mary Yeager-Armstead

Second Advisor

Gary Schultz

Third Advisor

Elmer Price

Fourth Advisor

Leslie Frost


Prymnesium parvum (P. parvum) is a toxin producing haptophyte that has spread globally over the past 100 years. The algae, initially a marine organism, has moved inland to less saline waters. In addition, there is variability in the efficacy of the toxins produced from bloom to bloom. Variation between strains has been suggested as the reason for bloom differences; however, environmental variability within a single strain must first be established. Here, a single strain of P. parvum was cultured at three environmentally relevant salinities, 6psu, 13psu, and 35psu. Three different environmental shocks, decreased temperature, raised pH, and addition of specific ions were applied to cultures of alga at each of the three salinities. Supernatant from each condition was used to test variability in hemolytic, cytolytic, and ichthyiotoxic properties. Culture salinity influenced growth rate of the algae, with increased growth rates at higher, marine salinities. Ichthyotoxicity of toxins produced were also increased with increased culture salinity. Cytolytic and hemolytic properties were found to vary with culture salinity; however, these properties were greatest at a culture salinity of 13psu. Environmental shocks also caused significant variability in efficacy of toxins produced. These tests demonstrate variability in toxic effect within a single strain of P. parvum and provide insight into the wide array of toxic effect in blooms worldwide.


Algal blooms -- Research.

Hypoxia (Water) -- Research.

Toxic algae -- Research.

Prymnesium parvum -- Research.