Accumulation and transformation of micro- and nano-plastics within the sea surface microlayer

微塑料和纳米塑料颗粒通过消费者的个人护理产品直接进入环境，并随着塑料包装等商业产品的风化和降解在环境中形成。海洋和沿海生态系统是塑料污染的主要汇。塑料已被证明在海洋生物中积累并对海洋生物的健康产生负面影响，这反过来又给生态系统以及依赖这些生态系统健康的海洋工业带来了额外的压力。这些小塑料颗粒的最终命运和不利影响取决于它们如何相互作用和在自然界中运输。海洋的一个重要自然组成部分和塑料污染的初始暴露点是海洋表面微层，它在全球范围内无处不在，由天然分子、颗粒物和微生物组成。这些微层起着“海洋皮肤”的作用，影响着海水和大气之间的质量和热量交换。它们也是微塑料和纳米塑料积聚的场所。该项目将研究微塑料和纳米塑料如何与模拟海洋表面微层相互作用，这些相互作用如何导致它们在海洋表面积聚和转化，以及微塑料和纳米塑料将在多大程度上改变海洋表面微层的性质。目标是提供导致微塑料和纳米塑料积累的界面和胶体特性的基本见解，这可以广泛地有助于确定塑料污染的环境风险和制定补救策略。通过与东北国家科学基金会路易斯·斯托克斯少数民族参与联盟项目合作，将扩大参与范围，为两名受支持的代表性不足的学生提供研究经验。这些学生还将领导一项新的中学外展活动。海洋表面微层厚度从1微米到1000微米不等，在全球海洋和沿海水域普遍存在，调节着这些水域与大气之间的质量和能量交换。海洋表面微层也是重金属、有机和微粒污染物（包括微塑料和纳米塑料）积聚的场所。该项目的动机是以下需求：具有代表性和商业相关性的微和纳米塑料，可用于实验室研究，广泛适用的合适微层系统，可实现与命运、运输和纳米级相互作用相关的可操作结果，以及表征含有颗粒物的海洋表面微层所需的显微镜技术。通过机械和紫外线降解将产生具有良好特征和尺寸分级的模型微纳米塑料（目的1）。浮游植物海面微层将在改进的Langmuir槽中制备（目标2），并用于量化微和纳米塑料的积累和转化，作为其物理性质和组成的函数（目标3）。为了实现该项目对教育、推广、多样性和包容性的更广泛影响，代表性不足的学生将参与研究活动，并将创建一个新的中学推广计划。海洋塑料为学生参与STEM活动提供了一个多功能和及时的平台。这项工作的变革方面源于对海洋表面微层在微和纳米塑料积累中的作用的有限理解，包括确定目前未知的相互作用和转化机制，展示利用复杂现场样品研究微和纳米颗粒与生物环境界面相互作用的能力，以及创建一个可以广泛应用于不同海洋和沿海地区的新实验框架。通过与东北国家科学基金会路易斯·斯托克斯少数民族参与联盟项目合作，将扩大参与范围，为两名受支持的代表性不足的学生提供研究经验。这些学生还将领导一项新的中学外展活动。该奖项反映了美国国家科学基金会的法定使命，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。

Microplastic and nano plastic particles enter the environment directly through consumer personal care products and are formed in the environment as commercial products such as plastic packaging weather and degrade. Oceans and coastal ecosystems are major sinks for plastic pollution. Plastics have been shown to accumulate in and negatively impact the health of marine life, which in turn places added stress on ecosystems as well as marine industries reliant on the health of these ecosystems. The ultimate fate and adverse impacts of these small plastic particles depends on how they interact and are transported in nature. A critical natural component of oceans and a point of initial exposure to plastic pollution are sea surface microlayers, which are ubiquitous globally and are comprised of natural molecules, particulate matter, and microorganisms. These microlayers act as an “ocean skin” that influences the exchange of mass and heat between the seawater and the atmosphere. They are also sites for microplastic and nano plastic accumulation. This project will study how microplastics and nano plastics interact with model sea surface microlayers, how these interactions cause them to accumulate and transform at the sea surface, and to what extent microplastics and nano plastics will alter the properties of sea surface microlayers. The goal is to provide fundamental insight into interfacial and colloidal properties leading to microplastic and nano plastic accumulation that can contribute broadly to determining environmental risks of plastic pollution and to devising strategies for remediation. Participation will be broadened by partnering with the Northeast NSF Louis Stokes Alliances for Minority Participation program to provide research experiences to two supported underrepresented students. These students will also lead a new middle school outreach activity. Sea surface microlayers, which range from 1 to 1000 micrometers thick, are ubiquitous globally on ocean and coastal waters, regulating the exchange of mass and energy between these waters and the atmosphere. Sea surface microlayers are also a site of accumulation for heavy metal, organic, and particulate pollutants including micro- and nano-plastics. This project is motivated by the following needs: Representative and commercially relevant micro- and nano-plastics enabling laboratory studies, suitable microlayer systems that are broadly applicable and enable actionable results relating to fate, transport, and nanoscale interactions, and microscopy techniques needed to characterize sea surface microlayers containing particulate matter. Well-characterized and size-fractionated model micro- and nano-plastics will be created by mechanical and UV degradation (Aim 1). Phytoplankton sea surface microlayers will be prepared in a modified Langmuir trough (Aim 2) and used to quantify the accumulation and transformation of micro- and nano-plastics as a function of their physical properties and composition (Aim 3). To realize the broader impact of the project to education, outreach, and diversity and inclusion, underrepresented students will be engaged in research activities and a new middle-school outreach initiative will be created. Marine plastics provide a versatile and timely platform to engage students in STEM activities. The transformative aspects of this work derive from the limited understanding of the role of the sea surface microlayers in micro- and nano-plastic accumulation and include identifying currently unknown mechanisms of interaction and transformation, demonstrating the ability to utilize complex field samples to study micro- and nano-particle interactions with bio-environmental interfaces, and creating a new experimental framework that can be broadly applied to different ocean and coastal regions. Participation will be broadened by partnering with the Northeast NSF Louis Stokes Alliances for Minority Participation program to provide research experiences to two supported underrepresented students. These students will also lead a new middle school outreach activity.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.