Year Established: 2020 Start Date: 2020-03-01 End Date: 2021-02-28
Total Federal Funds: $32,276 Total Non-Federal Funds: $34,369
Principal Investigators: Mathew Saxton
Abstract: Glyphosate is the most widely applied herbicide in the world. It is present in measurable concentrations in bodies of water that drain watersheds wherever the chemical is applied. Because the glyphosate chemical structure includes phosphorus and nitrogen, the two most important nutrients in most freshwater ecosystems, the contribution of this chemical to eutrophication has been of increasing interest. Bacterial biodegradation of glyphosate has been observed in bacterial cell culture and is presumed to occur in nature, but the gene pathways that drive this metabolism in the environment are unclear. Only a subset of the microbial population can degrade glyphosate and the known pathways result in the production of different breakdown chemicals, which are also only usable by particular microbial taxa. These processes must be better understood to obtain a full picture of Lake Erieâ€™s nutrient cycles and to specifically understand its recent algal bloom formation. We propose to expose naturally occurring Lake Erie microbial communities to glyphosate and its primary breakdown product AMPA, through microcosm experiments, and use a metatranscriptomic approach to measure the expression of genes involved in the microbial response to glyphosate exposure. This study will determine the microorganisms and degradation pathways responsible for the metabolism of glyphosate and its breakdown products. We will compare these experimental results to publicly available gene expression libraries collected directly from Lake Erie to confirm the importance of experimentally identified genes in the natural system. These results will resolve the pathways and chemical forms through which glyphosate is converted to nutrients that directly contribute to harmful algal bloom formation in Lake Erie.