Experimental assessment of the long-term ecological and evolutionary consequences of engineered nanoparticles

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Nanomaterials are materials with at least one critical dimension below 100 nm. Engineered nanomaterials, which constitute the building blocks of modern nanotechnology, are those engineered and manufactured by humans. Many engineered nanomaterials, including nanoparticles, nanotubes, and nanowires, display novel physical and chemical properties that are desirable for applications within the medical, industrial, commercial, and environmental sectors. As a result, a large number of commercial products using nanotechnology have been on the market, with thousands of tons of nanomaterials being produced each year. However, with the rapid development of nanotechnology, there is a greater risk for people and environment to be exposed to more nanotechnology-based products. Indeed, nanomaterials are known to enter the environment through both intentional and unintentional releases. Thus, a comprehensive understanding of the environmental impacts of nanomaterials is needed. However, much of the research on the environmental impacts of nanomaterials has focused on the responses of individual organisms or species after short-term exposure (from a few hours to a few days) to nanomaterials. There is little knowledge on how ecological communities, in which organisms interact with individuals of the same and other species, respond to engineered nanomaterials on longer timescales. It is imperative to fill this knowledge gap so that we can avoid potentially serious environmental consequences. In recognition of this pressing issue, this project, led by Lin Jiang and Yongsheng Chen of Georgia Institute of Technology, will investigate the long-term ecological and evolutionary consequences of cerium oxide (CeO2) nanoparticles, a type of metal oxide nanoparticle with various industrial applications. The findings of this project will contribute to a more complete understanding of the effects of engineered nanomaterials on the natural ecosystem. The project will also provide high-quality research training for graduate and undergraduate students, including those from underrepresented groups. Building on their previous work on the molecular, cellular, and species-level responses to engineered nanoparticles, the research team will use freshwater bacteria and protozoans as model organisms to evaluate the novel hypothesis that nanoparticles influence the strength of interactions between species, often more strongly than their non-nanoparticle counterparts, with ensuing consequences for population dynamics, community assembly, and biodiversity evolution. This project will fill a significant gap in our knowledge by applying ecological principles to understanding the effects of nanoparticles on species interactions and associated consequences. The proposed research will advance knowledge in four specific areas. First, it will address potential dynamical consequences of nanoparticles by studying their impacts on predator-prey interactions and population dynamics. Second, it will explore the likelihood that nanoparticles alter outcomes of competition by changing species relative competitive ability. Third, it will test the idea that nanoparticles may influence community assembly through modifying interactions between earlier and later colonizing species. Fourth, it will extend nanotoxicity investigations to the evolutionary timescale by investigating nanoparticle impacts on adaptive radiation. Consequently, the proposed research marries nanotoxicology with population biology and community ecology, contributing to the further development of nanotoxicology as an emerging discipline.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.