Determining Optimal Application Time of Dichlorogramine for Harmful Algal Bloom Control
Marie Spehlmann
Department of Biology
Faculty Supervisor: Zheng-Hui He
Harmful algal blooms are persistent and often devastating in aquatic systems due to a high influx of nitrogen and phosphorus from runoff. Greater nutrient availability drives algal blooms that can become toxic for humans and wildlife. Toxins from one of the most common bloom-forming cyanobacteria, Microcystis, are well known to cause human illnesses and wildlife mortalities. A novel naturally derived allelochemical compound, dichlorogramine (DCG), is effective in significantly reducing the growth of Microcystis aeruginosa (U.S. Pat. No. 8945397). Studies suggest DCG has no significant growth effect on plants, E. coli, and yeast cells, even at high concentrations. While DCG offers a promising solution to control Microcystis-related HABs, there is an existing need to determine the optimal application time of DCG. Current evidence suggests that delay of application following bloom conditions leads to diminished effectivity of DCG. In this study, various concentrations of Microcystis will be exposed to DCG and their optical densities will be measured for 10 days. By comparing the resulting growth curves, the algal concentration showing the lowest growth rate will be determined and used to guide future water management decisions. In the future, transcriptomics will be utilized to elucidate DCG’s mechanism of inhibition on Microcystis.