Collaborative Research: The Effects of Watershed Urbanization on In-Stream Transformation of Organic Nutrients within Running Waters

鉴于目前城市化的范围和规模，城市化已成为全球变化的关键组成部分。城市化地区的河流正在从反映景观和大气沉积的人为变化的分水岭养分输送转向积极改变进一步向下游输送的N和P的形态和生态影响的营养转化。关于沿海溪流在转化营养物质方面的潜在重要性以及由此对食物网的影响，信息不足。通过实地研究、流域评估和中观系统研究，这项研究将把流域城市化的变化与河流中有机形式营养物质的处理速度联系起来。创新的、最先进的分析方法将被用于构建质量平衡、评估生物有效性的变化、对分水岭源头进行指纹识别、评估转化率，并估计不同部分有机N&P在河流中产生的潜力。与正在进行的巴尔的摩LTER计划和栖息地地图的合作将用于将营养物质的转化与流域特征联系起来。结果将与沿海生态系统的富营养化问题具有广泛的相关性，并有助于确定溪流和河流何时有可能区分由于城市化程度提高而产生内部有机氮和磷的溪流和外部对无机氮和磷的补贴。欧空局种子项目的少数民族学生将参与这项研究。

ABSTRACTUrbanization has become a critical component of global change, given its current extent and magnitude. Streams in urbanizing areas are shifting from watershed nutrient transporters that reflect the anthropogenic changes in the landscape and atmospheric deposition to nutrient transformers that actively change the forms and ecological effects of N and P delivered further downstream. Insufficient information exists regarding the potential importance of coastal streams in transforming nutrients and consequent effects on foodwebs. Through field studies, watershed assessments, and mesocosm studies, the research will link changes in watershed urbanization to rates of in stream processing of organic forms of nutrients. Innovative, state-of-the-art analytical methods will be used to construct mass balances, assess changes in bioavailability, fingerprint the watershed source, assess transformation rates, and estimate the potential for in-stream generation of different fractions of organic N&P. Collaboration with the ongoing Baltimore LTER program and habitat mapping will be used to relate the nutrient transformations to watershed characteristics. Results will have broad relevance to eutrophocation problems in coastal ecosystems and help determine when streams and rivers have the potential to discriminate between streams that generate internal organic N&P from external subsidies of inorganic N&P as a result of increasing urbanization. Minority students from the ESA SEEDS project will participate in the research.