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

大多数生态系统在一定程度上受到人类活动的影响，但这种影响在不同地点之间可能会有很大差异。例如，城市对溪流和河流的影响因年龄、雨水基础设施、绿地数量和其他建成环境因素而有所不同。气候(温度和降水)和地质等自然因素也影响着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，将评估不同城市和气候背景的美国城市对河流中碳输入和输出的城市影响的差异。这项研究对于理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和研究生以及博士后学者提供培训机会、研讨会，以及为高中生提供的创新培训和实习计划。这项研究将采取一种新颖的方法，共同考虑生态系统生态的人类和生态维度如何相互作用，以控制进入整个大陆的流域的溶解有机碳(DOC)的质量、数量和时间。溶解有机碳是河流中最大的碳通量。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有的方式影响河流生态系统。研究人员将检验这一假设，即人类活动引入了新的DOC来源，并影响了不同地理位置和城市背景下生态过程的时空尺度和变异性。该假说将在五个城市研究区域--迈阿密、佛罗里达州、波士顿、马萨诸塞州、亚特兰大、佐治亚州、盐湖城、德克萨斯州和俄勒冈州的波特兰--用比较的方法进行检验，以了解城市对DOC的影响。对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)和控制DOC浓度、特征和生物有效性的生物物理因素(例如，排放、降水、树冠覆盖)。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。

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.