EAGER: Movement of microplastics within and between ecosystems: influences on zooplankton feeding behavior, primary productivity and nutrient availability in freshwater systems

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Increased global demand for plastic products in recent decades has greatly increased the amount of plastic waste entering the environment. Most plastics are persistent and will enter the environment at the end of their life cycle if not recycled or reused. Up to 94% of manufactured plastics end up in landfills or in the environment. In the environment, large plastic materials can be broken down through physical and chemical processes into small particles (0.1 to 5 mm). These microplastics can persist in the environment for long periods of time where they can fundamentally change how organisms interact with each other and with their physical environment. These changes can, in turn, change how microplastics move between ecosystems, and their fate in the environment. This has drawn the attention of scientists and environmental managers around the world. The goals of this project are to advance understanding of how ecosystems and communities of organisms respond to the presence of microplastics, and to provide information in support of better management of plastic pollution and problems arising from it. Moreover, this project will provide undergraduate and graduate students with research and career training in the fields of science, technology, engineering, and mathematics. This project will also provide opportunities for talented low-income high school students to participate in research and gain an understanding of the potential environmental impacts of plastic pollution, thus, enhancing a sense of environmental stewardship.This research will employ innovative designs and approaches developed based on observations and results of previous research to address two main objectives and test four detailed hypotheses. Objectives include, 1) characterize the movement of microplastics across terrestrial and aquatic ecosystems and 2) characterize the influence of algal colonization and biofilm development on microplastics surfaces on particle deposition rate, zooplankton feeding behavior and selectivity, phytoplankton community structure, primary productivity, and nutrient availability in freshwater systems. Hypotheses include, 1) deposition rates of suspended microplastics ingested and egested by aquatic organisms will be faster than natural abiotic depositional processes; 2) microplastics are transferred from aquatic to terrestrial ecosystems via emerging aquatic insects ingested by birds; 3) algal colonization and biofilm development on microplastic surfaces will increase deposition rates of suspended microplastics, alter phytoplankton community structure and primary productivity, and decrease nutrient availability in freshwater ecosystems; 4) in the presence of biofilm-covered microplastics, zooplankton will change feeding locations to areas of high concentrations of biofilm-covered microplastics and selectively feeding on them.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.