Life Sciences Commons^™

The Effects Of Variations In Light And Nutrient Availability On Phytoplankton And Zooplankton, Jake Anthony Swanson

Theses and Dissertations

Aquatic ecosystems experience a wide range of variation in resource availability; two of the resources that are most essential to phytoplankton and zooplankton are light and nutrients. Light can vary in both its color and intensity; these variations can directly impact phytoplankton by altering the amount and color of light available for photosynthesis. Nutrient variability, particularly increases in nutrient levels, also alter phytoplankton communities by favoring the growth of certain taxa such as cyanobacteria.

To understand whether phytoplankton respond differently to changes in light availability I investigated whether the diversification of cryptophytes, phytoplankton with diverse light-capturing pigments, showed evidence of …

Assessing The Competitive Advantage Of Carbonic Anhydrase In Estuarine Microalgae Through Removed Enzymatic Activity, Eilea R. Knotts

Theses and Dissertations

Carbon concentrating mechanisms (CCMs) are used by photoautotrophs to overcome possible limitations in carbon acquisition but the competitive strategies and efficiencies of these mechanisms among photosynthesizers can be variable. The diversity in carbon acquisition abilities establishes the potential for alterations in community structure with shifting carbon concentrations. Given the role of phytoplankton and benthic microalgae (BMA) in the trophodynamics of estuaries, understanding the mechanisms of carbon acquisition in these systems is important in predicting how primary productivity and nutrient cycling might change in response to increasing concentrations of atmospheric CO2. Our approach to investigate whether induced carbon limitation would show …

Interactive Effects Of Domoic Acid Allelopathy, Salinity, And Eutrophication On Estuarine Phytoplankton Community Structure, Elise Van Meerssche

Theses and Dissertations

Coastal regions and estuaries are particularly sensitive to the increase in nutrient loading and river runoff, threatening the ecosystems with possible spreads in harmful algal blooms (HABs). As an example, blooms of toxic Pseudo-nitzschia species can release acute concentrations of the neurotoxin domoic acid (DA) in the water column. When ingested at concentrations higher than 20 ppm, DA can cause the death of marine birds, marine mammals and even humans. The main objectives of my research were to determine the drivers of Pseudo-nitzschia abundance and toxicity and to assess how these drivers influenced the phytoplankton community structure and DA allelopathy. …