CAREER: Anthropogenic litter reveals drivers of ecosystem processes in urban streams

海洋中人工垃圾的堆积已经引起了公众的极大关注。人类的垃圾包括塑料、渔业废弃物和金属，这些都会对海洋资源产生负面影响。例如，一些垃圾可以被包括鸟类和海龟在内的有机体摄取，塑料可以分解成具有独特有毒特性的小颗粒。对海洋中垃圾的来源、移动和消耗的研究提供了有关洋流和食物网的信息。这位研究人员的研究表明，河流中的垃圾密度可以达到海洋中的类似密度。然而，河流中人类垃圾的来源、移动和对生物系统的影响尚不清楚，需要制定有效的预防战略和政策。此外，研究河流中垃圾的生态可能会揭示以前从未探索过的对生态系统结构和功能的控制。这项研究将在芝加哥和巴尔的摩地区的河流进行，包括高中生、本科生和研究生。学生教师将使用垃圾清除来开发课程，以教授跨年级的科学方法。这项研究将通过采用用于测量生物群落和有机物移动的基本工具，在3个大小的班级中考察人为垃圾(AL)的生态系统作用。首先，将衡量大型AL的作用。城市河流通常由于矫正和洪水管理而降低了河道的复杂性。大的AL可以起到人工礁石的作用。提供栖息地复杂性和有机质保留，这是其他方面所缺乏的，从而增强生物多样性。研究人员将在自然形成的泥石坝(即木材)和大型AL产生的泥石坝上测量溪流生物的丰度。接下来，这项研究将量化AL与微生物之间的相互作用。细菌、真菌和藻类在河流中进行重要的生物活动，清除多余的营养物质，并为昆虫和鱼类提供食物。初步研究表明，与自然表面相比，AL具有独特的微生物群落。实验将测试微生物如何受到铝表面的结构和化学性质的影响。最后，将检查中型(例如购物袋)和小型AL(例如微型塑料)的移动。初步研究表明，河流中的铝含量丰富且具有流动性，其中一部分总是向下游移动。因为AL吸收常见的有毒化学物质，它的移动可能是一条被忽视的途径，将毒素输送到下游并进入食物网。这项工作将量化城市溪流中落叶表面毒素的输入、输出和重新分布。

Accumulation of man-made trash in the oceans has received much public attention. Human trash includes plastic, fishing debris, and metal, which have negative effects on marine resources. For example, some trash can be ingested by organisms including birds and turtles, and plastic can break down into small particles that have unique toxic properties. The study of the origins, movement, and consumption of trash in the ocean has provided information about ocean currents and food webs. Research by this investigator has shown that trash in rivers can reach similar densities as in the oceans. However, the sources, movements, and influences on biological systems of human trash in rivers are unknown, and are needed to develop efficient prevention strategies and policies. Also, studying the ecology of trash in rivers may reveal previously unexplored controls on ecosystem structure and function. This study will be conducted in Chicago- and Baltimore-area rivers, and include students from high school, undergraduate, and graduate levels. Trash removal will be used by student teachers to develop lessons for teaching the scientific method across grade levels.This research will examine the ecosystem role of anthropogenic litter (AL) in 3 size classes by adapting fundamental tools used to measure communities of organisms and movement of organic matter. First, the role of large AL will be measured. Urban rivers typically have reduced channel complexity due to straightening and flood management. Large AL may act as an ?artificial reef,? providing habitat complexity and organic matter retention that is otherwise lacking, and thereby enhance biodiversity. Researchers will measure stream organism abundance at naturally occurring debris dams (i.e., wood) and at those generated by large AL. Next, this research will quantify interactions between AL and microbes. Bacteria, fungi, and algae carry out important biological activities in rivers, removing excess nutrients and providing food for insects and fish. Initial studies showed AL has unique microbial communities compared to natural surfaces. Experiments will test how microbes are affected by the structural and chemical properties of AL surfaces. Last, movement of intermediate-sized (e.g., shopping bags), and small AL (e.g., microplastic) will be examined. Initial research showed that AL in rivers is abundant and mobile, with some portion always moving downstream. Because AL attracts common toxic chemicals, its movement may be an overlooked pathway for delivery of toxins downstream and into food webs. This work will quantify inputs, outputs, and re-distribution of toxins on litter surfaces in urban streams.