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的问题。科学家们几乎在他们寻找过的任何地方都发现了塑料碎片，从人口稠密的城市到偏远的生态系统。在环境中发现的大多数塑料都是微塑料，主要来自较大的垃圾碎片的分解。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，也是复杂的化学混合物。高剂量的微塑料会以各种方式伤害动物，例如阻塞肠道或释放有毒化学物质。然而，我们不知道目前水平的微塑料污染是否会对环境造成损害。 我们在加拿大对这个问题的了解有限，尽管最近在全国各地的河流和湖泊中发现了微塑料。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，我的研究将让我们对微塑料如何改变哪些物种在湖泊中茁壮成长，以及这些生态系统中关键过程发生的速度有多快有了新的见解。这项工作是及时和相关的，因为几乎每一篇关于微塑料的科学评论都指出，缺乏关于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。我的研究直接满足了这一高度优先的研究需求。 在这笔拨款中，我建议在日益复杂的迷你湖泊中添加微塑料。只从水开始，随后的实验将逐步引入微小的植物，然后是小型无脊椎动物，最后是脊椎动物的加入。这一优雅的设计允许我们在一个复杂程度上学到的东西在下一个复杂程度上提供信息。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比率，以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，说明微塑料是否会对淡水湖以及我们作为一个社会最珍视的这些生态系统的特征产生负面影响，如果是这样的话。我预计我的研究将产生有趣的假说，这些假说将推动未来的生态学和生态毒理学研究，并支持基于证据的政策决策，以管理微塑料污染带来的潜在威胁。 更广泛地说，我的项目正在开创一个新的生态框架，以建立一个已建立的毒理学方法，将污染物暴露与不良后果联系起来。这样做将是一个重大的进步，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。这种框架很有可能在国际上被用来评估有毒化学品的环境风险。

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.