NSF Award
1715909
Cyanobacterial algal blooms plague lakes and rivers across the globe. These toxic blooms damage the health of lake ecosystems, threaten the public health of surrounding communities, and harm local economies due a reduction in tourism and fishing industries. Blooms are hard to combat, mainly because the factors that contribute to the successful growth of bloom-forming microbes are not yet fully understood. This project will provide new insight into how algal blooms occur by focusing on how the algae interact with surrounding bacteria to obtain and exchange the nutrients, especially nitrogen, that allow the blooms to occur. Through a combination of experimental manipulation, measurements, and physiological modeling, the work will provide a detailed picture of how nitrogen exchange promotes algal blooms. This results will help environmental managers develop effective mitigation strategies to combat toxic blooms in lakes and rivers. Experiments will be conducted by undergraduate students at James Madison and Wright State Universities, and much of the research will take place in an undergraduate classroom setting, providing excellent training for students early in their science careers. The researchers will also work with homeschooled students in rural areas, inspiring potential young scientists.<br/><br/>In aquatic systems, interactions between primary producers and heterotrophic bacteria alter water chemistry and shape ecosystem function. The goal of this project is to quantify and model interactions, specifically nitrogen exchange, between heterotrophic bacteria and a model primary producer in the phycosphere (the microenvironment surrounding a phytoplankton cell). This work will: 1) quantify the reliance of the model freshwater cyanobacterium Microcystis on the heterotrophic bacteria in the phycosphere; 2) quantify and model the transfer of nitrogen between Microcystis and specific phycosphere partners, using co-culture experiments with a single heterotrophic partner, and profile the transcriptome while simultaneously performing targeted nitrogen-related metabolite analysis; and 3) expand the model of nitrogen transfer to the entire phycosphere consortium by tracing and quantifying the flow of different nitrogen compounds through the symbiotic phycosphere consortium.
