CAREER: Impact of Urbanization on Organic Carbon-Metal Interactions and Trophic Transfer in Streams

1454448Vadas CAREER：城市化对河流中有机碳-金属相互作用和营养转移的影响在日益城市化的景观中，来自雨水和废水流出物的金属对河流中生物的负面影响将继续上升。虽然大多数河流生物的金属生物可利用性模型的重点是环境暴露于溶解的金属相，但这项拟议的研究也讨论了有机物的附着和摄取在控制生物吸收金属方面的不可或缺的作用。在生态系统尺度上，金属吸收和保留的生物动力学与金属和有机物的特性、暴露模式和溪流生物的取食行为有关。评估金属形态和大小分布以及与金属吸收有关的有机质特征是制定生态系统一级暴露评估模型所必需的知识，这些模型有助于制定溪流管理战略。除了拟议的研究，教育计划还将支持1名硕士和1名博士生以及至少2名本科生的培训。强化的学生培训将侧重于相关学科的额外课程作业和沟通技能，以促进未来的跨学科研究。将根据国家教育指导方针，为K-12课堂开发教育模块。这些模块将通过康涅狄格大学的达芬奇计划传播，以扩大它们的影响范围，超越个人课堂。该项目的一个重要方面将是通过关注基本理解和跨学科交流，将生态和环境工程整合到所有级别的教育中：将为大学水平的教育开发几个跨学科的基于问题的学习练习，并将开发和广泛分布与溪流障碍相关的K-12教育模块。这一职业发展计划解决了与为城市地区的溪流障碍制定更有效的管理战略相关的研究和教育挑战。现有的评估和管理受损河流的框架没有解决河流中存在的动态和独特的情况。铜和锌等金属既是必需的，也是有毒的，这取决于浓度，是最常见的损害原因之一。然而，在所有大小范围内与有机物的强烈相互作用以及损害的流出物和雨水来源的暴露模式的差异是巨大的。总金属负荷量不一定是生物吸收的良好指标，必须同时考虑金属的稳定性和对不同有机金属颗粒的摄取。为了解决与不同金属来源相关的河流损害问题，需要对城市河流条件下的金属生物吸收有更全面的了解。为实现这一目标，以下目标和办法将是：1)量化不同河流来源水中金属形态和粒度分布的时空变异性：自动采样器将在城市到郊区的一系列受损地点分别收集流出物和雨水径流的时间间隔和流量加权样本。样品将被分成与生物吸收相关的粒度组分，并分析总金属、有机物、胶体金属和有机物的粒度分布，以及有机物的光学、化学和金属结合特性。2)确定初级生产者和高营养级别生物吸收的金属形态和大小分布预测因子以及对金属负荷动态的依赖：将分析金属吸收和附着作为不同来源水体中有机物的大小分布和化学特征的函数。生物动力学模型将评估藻类对金属的净吸收，并随后转移到营养级别较高的生物体。这些将在模拟河流的暴露制度下进行检查，例如，对于流出源，采用不同的源水与溪水比例，对于雨水径流，采用不同的暴露浓度。

1454448VadasCAREER: Impact of Urbanization on Organic Carbon-Metal Interactions and Trophic Transfer in StreamsIn an increasingly urbanizing landscape, the negative impact of metals from both stormwater and wastewater effluent on organisms in streams will continue to rise. While the focus of most metal bioavailability models for stream organisms is on ambient exposure to dissolved metal phases, this proposed research also addresses the integral role of attachment and ingestion of organic matter in controlling bio-uptake of metals. At the ecosystem scale, the biodynamics of metal uptake and retention relate to both metal and organic matter characteristics, exposure patterns and feeding behavior of stream organisms. Assessment of metal speciation and size distribution as well as organic matter characteristics as related to metal uptake is required knowledge for the development of ecosystem level exposure assessment models that are useful for establishing management strategies for streams. In addition to the proposed research, the education plan will support the training of 1 M.S. and 1 Ph.D. student and at least 2 undergraduate researchers. Enhanced student training will focus on additional coursework in related disciplines and communication skills to promote interdisciplinary research in the future. Educational modules will be developed for K-12 classrooms according to State education guidelines. These modules will be disseminated through the DaVinci program at the University of Connecticut to broaden their reach beyond an individual classroom. A significant aspect of this project will be integrating ecology and environmental engineering across all levels of education through a focus on basic understanding and communication across disciplines: Several interdisciplinary problem-based learning exercises will be developed for university level education and K-12 education modules related to stream impairment will be developed and distributed widely.This career development plan addresses the research and education challenges associated with developing more effective management strategies for impaired streams in urban areas. The existing framework to assess and manage impaired streams does not address the dynamic and unique conditions present in streams. Metals such as copper and zinc are both necessary and toxic depending on the concentration, and are one of the most common causes of impairment. However, the strong interaction with organic matter across all size ranges and differences in exposure patterns of the effluent and stormwater sources of impairment are dramatic. Total metal loads are not necessarily good indicators of bio-uptake and both metal lability and ingestion of the different organic-metal particulates must be considered. In order to address the stream impairment issues associated with different metal sources, a more complete understanding of metal bio-uptake under urban stream conditions is required. To accomplish this, the following objectives and approach will be: 1) Quantify the variability of metal speciation and size distribution in different stream source waters across space and time: Automated samplers will collect time interval and flow-weighted samples of effluent and stormwater runoff, respectively, at impaired sites across a range of urban to suburban sites. Samples will be separated into size fractions relevant to biotic uptake and analyzed for total metals, organic matter, colloidal metal and organic matter size distribution, and organic matter optical, chemical and metal binding characteristics. 2) Identify metal speciation and size distribution predictors of biological uptake in primary producers and higher trophic level organisms and the dependence on metal loading dynamics: Metal uptake and attachment will be analyzed as a function of size distribution and chemical characteristics of the organic matter in different source waters. Biodynamic modeling will assess the net metal uptake into algae and subsequent transfer to higher trophic level organisms. These will be examined under exposure regimes that mimic the stream, e.g. with different ratios of source water to stream water for effluent sources and varying exposure concentrations for stormwater runoff.