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

溪流和河流比水和溶解在水中的物质移动得更多-它们还携带着一种复杂的小颗粒混合物，统称为Seston。沉积物通常包括泥沙、粘土、有机物质和源自周围陆地或在溪流中产生的微生物。虽然在暴雨过后的浑浊河流中可以看到溪流输送的Seston的重要性，但这些颗粒在溪流中的作用仍然知之甚少。然而，随着Seston向下游移动，它可以发挥许多关键作用，包括作为溪流动物的食物和能源，以及作为沿海生态系统的生命构成元素碳、氮和磷的来源。利用国家生态观测网(NEON)站点的现场样本和环境传感器的高频水质数据，该项目将增加我们对细颗粒物在溪流中传播时所起作用的了解。该项目的结果将有助于改进对河流颗粒物从陆地带到海岸的碳、氮和磷的估计。这些数据可以用来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。霓虹灯数据将被用于将数据科学技术、计算机建模和图形分析引入该团队开发的几门本科课程，并将公开提供教育模块。Seston在流动水域中的作用和重要性被低估，这既是因为它的组成多样化，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。该项目将增加对河流Seston的组成以及Seston如何将河流中的碳、氮和磷耦合起来的了解。该小组将检验三个互补性假说，它们将扩大对Seston在河流通量中作用的理解：1)Seston的组成取决于大陆尺度的地质和气候模式；2)Seston是陆地和河流中生物地球化学过程的综合信号，根据季节或水文背景而变化；3)Seston的数量和质量将揭示将源头与更大河流连接起来的河流网络规模的过程。该项目将利用22个可摆动溪流和河流霓虹灯站点的新的和正在进行的数据收集工作，以衡量Seston的质量和数量。这些数据将被用来开发Seston组成和跨季节、水文条件和霓虹区输送的预测模型。通过揭示Seston在地方、区域和大陆尺度的河流碳和营养生物地球化学中的作用，这里提出的工作将提供所需的关键数据，以对进一步定义河流在全球生物地球化学循环中的作用的模型进行参数化。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.