EiR: Untangling the role of predatory bacteria and other micro-predators in marine systems: Discovery, Predation, Ecology and Interactions and Impact of Environmental Factors.

About This Grant

Bacteria are the most numerous living organisms on Earth, without them life could not be sustained. Yet, if microbes were to grow out of control, they would cover the Earth’s surface with a thick layer of slime that would engulf and strangulate life forms. Fortunately, nature has incorporated factors to control microbial growth, including the function that predators of bacteria or micropredators perform. The most studied bacterial control mechanism are viruses that infect and kill bacteria, and protists that feed on bacteria by grazing. Another documented micropredators are the bacterial group Bdellovibrio, and like organisms, a group of bacteria that uniquely prey upon and kill other bacteria. However, little is known about their role. In the global ocean carbon cycle, dissolved organic matter (DOM) is released by higher organisms in the ocean and subsequently is taken up and utilized most efficiently by bacteria. These bacteria can subsequently be preyed upon by micropredators releasing the DOM back into the environment to serve as nutrients into the classic food web. This critical carbon cycling process can be impacted by environmental changes. Among the environmental changes that impact the carbon cycle are rising ocean temperatures, acidity, and eutrophication. The researchers will investigate the impact of these parameters on micropredators and microbial dynamics. The results will advance the understanding of the factors that impact micropredators, micropredation and the microbial loop, and test the tipping point at which the microbial loop dynamics become impaired. It is of significant human interests to understand these processes. In addition, there is a national need to increase the number of students with an interest in STEM, particularly geosciences. The researchers view k-12 teachers as the vehicles of the change needed to achieve this goal. As such, they are the primary focus group for the educational component of this project. The research team aims to empower and incentivize middle and high school STEM teachers by providing professional development activities to expand the depth and breadth of their scientific knowledge, improving students’ learning and enthusiasm in STEM as a result. The researchers will accomplish this by actively engaging teachers in the research aspects of this project. Utilizing the knowledge and experiences they will acquire, these teachers will have the potential to reach over a thousand students in five years, a great societal benefit. To investigate the impact of ranges in ocean temperature, acidification and nutrients on micropredators and their rate of predation, the research team will monitor and quantify their abundances in time-series experiments at 3-to-6-hour intervals at various environmental conditions. The primary methods for quantification of the micropredators and prey will be qPCR, flow cytometry, and direct microscopic counting. The researchers will also use metagenomics for community analysis. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.