CUR - The Council on Undergraduate Research

Exploring the Compounding Effects of Common Pesticides  on Freshwater Microbiomes

Gabriel Hooper, Nathan Edmondson, John Hoverson, Mark Fischer, Matthew Becker, & Kyle Harris, Department of Biology and Chemistry, Liberty University, 1971 University Blvd, Lynchburg, VA 24515.

The prevalent use of pesticides throughout the United States has resulted in unintended negative consequences for non-target organisms. Rain run-off can move multiple pesticides into environments bringing them into contact with non-target organisms that have variable tolerances to pollution. There are limited studies on how the compounding effects of pollutants impact freshwater microbiomes. Previous research conducted by our lab observed that acute treatment of common herbicides on crayfish annelid ectosymbionts resulted in mortality.  Therefore, we selected a similar combined treatment to investigate the effect of these environmentally relevant pesticide concentrations on the microbiomes of the crayfish and their environment (sediment and water). This project examines these microbiomes before and after a 48-hour exposure to 2000 ppb of herbicides (glyphosate, atrazine, and 2,4-D) and seeks to answer two questions: 1) Will acute exposure to pesticides reduce bacterial diversity and richness within a freshwater environment (water and substrate) and on biota (crayfish)? and 2) Will certain bacterial populations in the microbiome be more resilient to acute pesticide exposure? We expect that acute pesticide exposure will: 1) reduce bacterial diversity and richness across sample types and 2) that the acute exposure will result in a shift in bacterial populations which predominate in the resulting microbiomes. This study seeks to improve our understanding of how an acute exposure to pesticides may restructure microbial communities on crayfish hosts and in freshwater environments. 

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