Collaborative Research: MRA: ConFines: Continental-scale study of the role of fine particles in riverine material fluxes

溪流和河流的流动不仅仅是水和溶解在水里的物质它们还携带着复杂的小颗粒混合物，统称为悬浮物。Seston通常包括淤泥，粘土，有机物质和微生物，它们来自周围的土地或在溪流本身中产生。虽然在暴雨后的泥泞河流中可以看到河流输送悬浮物的重要性，但这些颗粒在河流中的功能仍然知之甚少。然而，随着悬浮物向下游移动，它可以发挥许多关键作用，包括作为河流动物的食物和能量，以及作为沿海生态系统的生命构建元素碳，氮和磷的来源。利用国家生态观测网（氖）站点环境传感器的现场样本和高频水质数据，该项目将增加我们对细颗粒在溪流中传播时的作用的理解。该项目的结果将有助于精确估算河流颗粒从陆地带到海岸的碳、氮和磷。这些数据可用于为全球地球系统模型提供信息。本科生和研究生将参与这项研究。氖数据将用于将数据科学技术、计算机建模和图形分析引入几门本科课程，该团队开发的教育模块将公开提供。悬浮物在流动沃茨中的作用和重要性未得到充分认识，这既是因为其成分的多样性，也是因为与能够捕获空间和时间动态的稳健采样相关的挑战。这个项目将增加对河流悬浮物组成的了解，以及悬浮物如何在河流中耦合碳，氮和磷的运输。该小组将测试三个互补的假设，以扩大对悬浮物在河流通量中的作用的理解：1）悬浮物的组成取决于大陆尺度的地质和气候模式; 2）悬浮物是陆地和河流生物地球化学过程的综合信号，根据季节或水文环境而变化;悬浮物的数量和质量将揭示连接源头与较大河流的河流网络尺度过程。该项目将利用22个可涉水溪流和河流氖站点的新的和正在进行的数据收集工作来测量悬浮物的质量和数量。这些数据将被用来开发预测模型悬浮物的组成和运输跨季节，水文条件，和氖域。通过阐明悬浮物在局部、区域和大陆尺度上对河流碳和营养盐地球化学的作用，这里提出的工作将为进一步确定河流在全球地球化学循环中的作用的参数化模型提供所需的关键数据。该奖项反映了NSF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。

Streams and rivers move more than water and the material dissolved in it—they also carry a complex blend of small particles, collectively called seston. Seston typically includes silt, clay, organic material, and microbes that originate from the surrounding land or that are produced within the stream itself. While the significance of seston transported by streams can be seen in a muddy river after a rainstorm, the function of these particles in streams remains poorly understood. However, as seston moves downstream it can serve many crucial roles, including as food and energy for stream animals and as a source of the life-building elements carbon, nitrogen, and phosphorus for coastal ecosystems. Using field samples and high-frequency water quality data from environmental sensors at National Ecological Observatory Network (NEON) sites, this project will increase our understanding of the role of fine particles as they travel in streams. Results from the project will help to refine estimates of carbon, nitrogen, and phosphorus carried from the land to the coast by riverine particles. These data can be used to inform global earth-system models. Undergraduate and graduate students will participate in this research. NEON data will be used to introduce data-science techniques, computer modeling, and graphical analysis into several undergraduate courses and educational modules developed by the team will be made publicly available. The role and importance of seston in flowing waters is underappreciated, both because of its diverse composition and because of challenges associated with robust sampling capable of capturing spatial and temporal dynamics. This project will increase understanding of riverine seston composition as well as how seston couples carbon, nitrogen, and phosphorus transport in rivers. The team will test three complementary hypotheses that will expand understanding of the role of seston in riverine fluxes: 1) seston composition depends on continental-scale patterns in geology and climate; 2) seston is an integrated signal of terrestrial and in-stream biogeochemical processes that varies according to seasonal or hydrologic context; and 3) seston quantity and quality will reveal river network-scale processes that connect headwaters to larger rivers. This project will leverage new and ongoing data collection efforts at 22 wadeable-stream and river NEON sites to measure seston quality and quantity. These data will be used to develop predictive models for seston composition and transport across seasons, hydrologic conditions, and NEON domains. By shedding light on the role of seston in riverine carbon and nutrient biogeochemistry at the local, regional, and continental scale, the work proposed here will provide key data needed to parameterize models that further define the role of rivers in global biogeochemical cycles.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.