Atrazine and Glyphosate are the most commonly applied herbicides in the United States, and herbicide usage is expected to increase in the coming decades as population increases demand more crop production. While research shows that some freshwater bacterial strains are capable of degrading herbicides, thereby introducing Carbon- and Phosphorous-rich nutrients into the ecosystem, further research is needed to gain an accurate understanding of the complexities of freshwater microbial community interactions under these circumstances. In the summer of 2021, the Saxton lab collected water samples from Acton Lake and isolated 70 bacterial strains capable of utilizing Atrazine or Glyphosate as their sole source of Phosphorus or Carbon. This research project aimed to physiologically characterize the 70 bacterial strains by measuring their growth rates. This included raising triplicates of each of the 70 samples, and utilizing a spectrophotometer to measure OD twice per day over 5 days. The Atrazine-degrading bacteria showed more taxonomic diversity, and were associated with the orders Burkholderiales, Pseudomonadales, and Mycobacteriales. All Glyphosate-degrading bacterial strains were associated with Mycobacteriales. The range of growth rate values was also more diverse in the Atrazine-degrading strains. The eventual results of this study may be published as a part of a comparative genomics paper. Previous research has consistently demonstrated that pesticide runoff into water basins contributes to the growth of harmful algal blooms. As the bacteria collected during this study are capable of degrading Atrazine or Glyphosate, they likely play some role in contributing to algal blooms by converting each pesticide into nutrients readily utilized by algae. The characterization of each isolate will be used as a jumping-off point for further investigation into how these bacteria interact with bloom-causing algae. More research is needed to determine how microbial communities interact and respond to pesticide runoff, and to explore the feasibility of bioremediation.
Author(s): Helena Hitch, Iyana Oliviel, Oluwaseun Olubodun, Matthew Saxton
Advisor(s): Matthew Saxton, Biological Sciences
Oluwaseun Olubodun, Biological Sciences
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