A New Ecological Framework for Adverse Outcomes of Contaminants on Ecosystems: Microplastics as a Case Study

塑料污染现在被认为是一个全球性问题。从人口稠密的城市到偏远的生态系统，科学家们几乎在他们所看到的任何地方都发现了塑料碎片。环境中发现的大多数塑料都是微塑料，它们主要来自较大垃圾的分解。微塑料正在挑战我们对污染物的科学理解，因为它们既是颗粒又是化学物质的复杂混合物。高剂量的微塑料会以多种方式伤害动物，例如阻塞肠道或释放有毒化学物质。然而，我们不知道目前的微塑料污染水平是否对环境造成危害。 尽管最近在加拿大各地的河流和湖泊中发现了微塑料，但我们对加拿大这个问题的了解仍然有限。在 NSERC 的资助下，我将研究微塑料对淡水生态系统结构和功能的影响。更简单地说，我的研究将为我们提供关于微塑料如何改变哪些物种在湖泊中繁衍生息，以及这些生态系统中关键过程发生的速度的新见解。这项工作是及时且相关的，因为几乎所有有关微塑料的科学评论都指出缺乏有关这些污染物如何影响更高水平的生物组织的信息。值得注意的是，这在最近发布的《加拿大塑料科学议程》中得到了呼应。我的研究直接解决了这一高度优先的研究需求。 在这笔赠款中，我建议将微塑料添加到日益复杂的迷你湖中。从仅水开始，后续实验将逐步加入微型植物，然后是小型无脊椎动物，最后添加脊椎动物。这种优雅的设计使我们在一个复杂级别上学到的知识能够为下一个复杂级别提供信息。在我们的模型生态系统中，我们将监测社区以及关键生态系统功能的速率如何应对不同程度的污染。 我的研究将为加拿大的环境科学和政策做出贡献。我的研究将产生科学证据，证明微塑料是否会对淡水湖以及我们作为一个社会最重视的生态系统的特征产生负面影响，如果是的话，会如何产生负面影响。我希望我的研究能够产生有趣的假设，这些假设将推动生态学和生态毒理学的未来研究，并支持基于证据的政策决策，以管理微塑料污染造成的潜在威胁。 更广泛地说，我的项目正在开创一个新的生态框架，建立一个既定的毒理学方法，将污染物暴露与不良后果联系起来。这样做将是一个重大进步，因为我的领域几十年来一直在努力将生态纳入生态毒理学。这样的框架具有在国际上被采用来评估有毒化学品环境风险的巨大潜力。

Plastic pollution is now recognized as a global issue. Scientists have found plastic debris virtually everywhere they have looked, from densely populated cities to remote ecosystems. Most plastics found in the environment are microplastics, which primarily come from the breakdown of larger pieces of litter. Microplastics are challenging our scientific understanding of contaminants because they are both particles and a complex mix of chemicals. High doses of microplastics can harm animals in various ways, such as obstructing the gut or releasing toxic chemicals. However, we don't know if current levels of microplastic pollution are causing harm to the environment. Our knowledge of this issue in Canada is limited, despite microplastics being recently found in rivers and lakes across the country. With funding from NSERC, I will examine the effects of microplastics on structure and function of freshwater ecosystems. More simply, my research will give us new insights into how microplastics change which species thrive in lakes, as well as how quickly critical processes happen in these ecosystems. This work is timely and relevant because virtually every scientific review written about microplastics points to the lack of information on how these contaminants impact higher levels of biological organization. Notably, this was echoed in the recently released Canadian Plastics Science Agenda. My research directly addresses this high-priority research need. In this grant, I propose to add microplastics to mini-lakes' of increasing complexity. Starting with water only, subsequent experiments will phase-in microscopic plants, followed by small invertebrates, and culminating in the addition of vertebrates. This elegant design allows what we learn at one level of complexity to inform the next. In our model ecosystems, we will monitor how the community, as well as rates of critical ecosystem functions, respond to different levels of pollution. My research will contribute to environmental science and policy in Canada. My research will generate scientific evidence as to if, and if so how, microplastics negatively impact freshwater lakes and the characteristics of these ecosystems we most value as a society. I expect my research to generate intriguing hypotheses that will drive future research in ecology and ecotoxicology and support evidence-based policy decisions for managing potential threats posed by microplastic pollution. More broadly, my program is pioneering a new ecological framework for an established toxicological approach to link contaminant exposure with adverse outcomes. Doing so would be a significant advance because my field has been struggling for decades to put the eco' into ecotoxicology. Such a framework has strong potential to be adopted internationally to assess environmental risks of toxic chemicals.