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

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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.