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

近几十年来，全球对塑料制品的需求增加，大大增加了进入环境的塑料废物量。大多数塑料具有持久性，如果不回收或重复使用，将在其生命周期结束时进入环境。高达94%的塑料制品最终进入垃圾填埋场或环境中。在环境中，大的塑料材料可以通过物理和化学过程分解成小颗粒（0.1至5 mm）。 这些微塑料可以长期存在于环境中，从根本上改变生物体相互作用及其与物理环境的相互作用。这些变化反过来可以改变微塑料在生态系统之间的移动方式及其在环境中的命运。这引起了全世界科学家和环境管理者的注意。本项目的目的是进一步了解生态系统和生物群落对微塑料的反应，为更好地管理塑料污染和由此产生的问题提供信息，并为本科生和研究生提供科学、技术、工程和数学领域的研究和职业培训。本项目还将为有才华的低收入高中生提供参与研究的机会，了解塑料污染对环境的潜在影响，从而增强环境管理意识。本研究将采用基于以往研究的观察和结果而开发的创新设计和方法，以解决两个主要目标并验证四个详细假设。目标包括：1）描述微塑料在陆地和水生生态系统中的运动; 2）描述微塑料表面上藻类定植和生物膜发育对颗粒沉积速率、浮游动物摄食行为和选择性、浮游植物群落结构、初级生产力和淡水系统中营养物质可用性的影响。假设包括，1）水生生物摄入和排泄的悬浮微塑料的沉积速率将快于自然非生物沉积过程; 2）微塑料通过鸟类摄入的新兴水生昆虫从水生生态系统转移到陆地生态系统; 3）微塑料表面上的藻类定殖和生物膜发展将增加悬浮微塑料的沉积速率，改变浮游植物群落结构和初级生产力，减少淡水生态系统中的营养物质; 4）在生物膜覆盖的微塑料的存在下，浮游动物会将觅食地点转移到生物膜高浓度的区域，该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.