Bioavailability and biological effects of microscopic plastic debris in the ocean

每年有数百万吨塑料垃圾被丢弃，海洋塑料垃圾正在成为对海洋的威胁和社会管理的重大挑战。一旦塑料垃圾进入海洋，风和潮汐的共同作用会导致较大的塑料碎片破碎成微观颗粒。这些微小的颗粒已经变得如此之多，要么漂浮在海洋中，要么积累在沉积物和海岸线上，它们正在成为一个高度关注的全球保护问题。我们一直在研究当微塑料被海洋食物网低端的海洋生物摄入时会发生什么，包括在表面沃茨游泳和觅食的浮游动物以及生活在海底沉积物中的海洋蠕虫。在我们的实验室研究中，在食物中摄入微塑料会导致体重和生殖能力的减少。颗粒被排出后，它们在水柱中下沉得更慢。这一点很重要，因为浮游动物和蠕虫（所谓的次级生产者）的生物量以及粪便颗粒的下沉速度对海洋中碳和其他营养物质的循环极其重要，而碳和其他营养物质又是支持所有海洋生物的核心。在本提案中，我们将以这些早期发现为基础，确定它们对海洋生物的重要性。我们将详细研究从英国沃茨海岸线附近收集的浮游动物实际摄入了多少微观塑料。我们将从一年的周期中采集样本，以了解塑料碎片的丰度及其被浮游动物摄入的量如何随季节周期而变化。我们将研究塑料的大小、形状和类型等因素，这些因素会影响塑料微粒的消耗量，以及它可能对水族馆中的生物产生的生物效应。我们将把这些结果输入到海洋功能模型中，以预测哪些地点（如果有的话）最容易受到微塑料污染，以及微塑料的密度可能与无脊椎动物猎物的密度相当。然后，我们将使用模型来预测这种污染对重要海洋功能的影响，例如存在的动物类型以及整个水柱中碳和营养物质的循环。该项目将提供重要的科学成果，以提高我们对海洋关键生态功能的理解，说明我们丢弃的废物如何能够影响重要的海洋进程，并可能突出需要特别保护的脆弱地点或物种。这些数据将对环境管理人员和政策制定者有用，法律要求他们保持我们的海洋清洁，减少对人类和海洋健康直接或间接损害的风险。最终，研究结果对社会上的每个人都很重要，并可能有助于建立一个证据体系，鼓励我们首先不要乱扔垃圾。

Every year, millions of tonnes of plastic debris is discarded as waste and marine plastic litter is emerging as both a threat to the oceans and a major challenge for society to manage. Once plastic waste has entered the sea, the combined action of winds and tides leads to the fragmentation of larger plastic debris into microscopic particles. These microscopic particles have become so numerous, either floating in the ocean or accumulating in sediments and on shorelines, that they are emerging as a global conservation issue of high concern. We have been studying what happens when microplastics are ingested by marine organisms at the lower end of the marine food web, including zooplankton that swim and feed in surface waters and marine worms that live in sediments at the ocean bottom. In our laboratory studies, ingestion of microplastics alongside food items led to reductions in body mass and reproduction. After the particles had been egested, they sank more slowly in the water column. This is important because the biomass of zooplankton and worms (so-called secondary producers) and the sinking rates of faecal pellets, are extremely important for the cycling of carbon and other nutrients in the oceans, which in turn is central to supporting all marine life. In this proposal, we will build on these early findings to determine their significance for ocean life. We will study in detail how much microscopic plastic is actually being ingested by zooplankton collected from sites near to shorelines in UK waters. We will take samples from across a yearly cycle to understand how the abundance of plastic debris and its ingestion by zooplankton vary with seasonal cycles. We will study the factors such as size, shape and type of plastic that influence how much microplastic is consumed and the biological effects that it may have on organisms in the aquarium. We will enter these results into models of ocean functions to predict what sites, if any, are most vulnerable to microplastics contamination and where the densities of microplastics may become comparable to those of invertebrate prey items. We will then use models to predict the impacts of this contamination on important ocean functions, such as the types of animals present and the cycling of both carbon and nutrients throughout the water column. This project will provide important scientific results to improve our understanding of key ecological functions in the oceans, illustrate how our discarded waste materials may be capable of impacting on important ocean processes, and may highlight vulnerable sites or species that require special protection. This data will be of use to environmental managers and policy makers who are required by law to keep our seas clean and reduce the risk of direct or indirect harm to human and ocean health. Ultimately the results are important to everyone in society, and may help to build up a body of evidence to encourage us not to litter in the first place.