Collaborative Research: Scales and drivers of variability in dissolved organic carbon across diverse urban watersheds

大多数生态系统都在一定程度上受到人类活动的影响，但这在不同地点之间可能有很大差异。例如，城市对溪流和河流的影响因年龄、雨水基础设施、绿色空间的数量和建筑环境的其他因素而异。气候（温度和降水）和地质等自然因素也会影响不同城市在一年中不同时间对水质和水量的影响。在这个项目中，城市对河流中碳输入和输出的影响差异将在美国不同城市和气候背景下进行评估。这项研究对于了解城市河流的生态模式和过程至关重要。这项工作的更广泛影响将包括为本科生、研究生和博士后学者提供培训机会，举办研讨会，并为高中生提供创新的培训和实习计划。这项研究将采取一种新颖的方法，共同考虑生态系统生态学的人类和生态维度如何相互作用，以控制质量、数量、以及溶解有机碳（DOC）--溪流中最大的碳通量--进入整个大陆流域的时间。该项目将评估城市化如何影响DOC，重点是城市化如何以区域特定方式影响河流生态系统。研究人员将测试这一假设，即人类活动引入DOC的新来源，并影响不同地理和城市环境中生态过程的时空尺度和变异性。该假设将使用比较方法进行检验，以了解城市对五个城市研究区域DOC的影响-佛罗里达州迈阿密、马萨诸塞州波士顿、佐治亚州亚特兰大、犹他州盐湖和俄勒冈州波特兰。DOC浓度和质量的广泛天气采样将与密集的传感器网络相结合，以发展对城市系统中DOC数量和质量的多尺度理解。空间统计和时间序列分析将确定人类发展的关键时空特征（例如，废水基础设施、住房密度）和生物物理因素（例如，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。

Most ecosystems are impacted by human activities to some degree, but this can vary considerably beteween locations. For example, cities differ in their impacts on streams and rivers depending on age, storm water infrastructure, amount of green space, and other factors of the built environment. Natural factors such as climate (temperature and precipitation) and geology also affect how different cities influence water quality and quantity at different times of the year. In this project, differences in urban impacts on carbon inputs and outputs in streams will be evaluated across cities in the U.S. that have different urban and climate contexts. This research is critical for understanding ecological patterns and processes in urban streams. Broader impacts of the work will include training opportunities for undergraduate and graduate students and postdoctoral scholars, workshops, and an innovative training and internship program for high school students.This study will take a novel approach to jointly consider how the human and ecological dimensions of ecosystem ecology interact to control the quality, quantity, and timing of dissolved organic carbon (DOC) – the largest flux of carbon in streams – entering watersheds across the continent. This project will assess how urbanization affects DOC, focusing on how urbanization affects stream ecosystems in regionally-specific ways. Researchers will test the hypothesis that human activities introduce novel sources of DOC and affect the spatial and temporal scales and variability of ecological processes in different geographies and urban contexts. The hypothesis will be tested using a comparative approach to understand urban effects on DOC in five urban study areas – Miami, FL, Boston, MA, Atlanta, GA, Salt Lake City, UT, and Portland, OR. Extensive synoptic sampling of DOC concentrations and quality will be combined with intensive sensor networks to develop a multi-scale understanding of the quantity and quality of DOC in urban systems. Spatial statistics and time-series analyses will identify key spatio-temporal characteristics of human development (e.g., wastewater infrastructure, housing density) and biophysical factors (e.g., discharge, precipitation, canopy cover) that control the concentration, characteristics, and bioavailability of DOC.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.