DISSERTATION RESEARCH -- The Effects of Urbanization on Nitrate Removal Capacity of Urban Wetlands

摘要建议：Deb 0507973 PI：Ehrenfeld，Joan Institution：Rutgers人类活动，特别是化石燃料燃烧和化肥生产，正在向生态系统增加大量的氮(N)。这种过量的氮导致了许多环境问题，包括富营养化、沿海水域缺氧、物种多样性的丧失以及饮用水的毒性。湿地系统通常具有很高的氮保持能力，因为它们的湿润土壤促进了反硝化作用，这是一种将硝酸盐转化为氮气的土壤过程。然而，城市地区的湿地可能没有同样的去除N的能力，因为城市化导致的水文变化使城市湿地比历史上更干燥，从而抑制了反硝化的N去除过程。虽然已知土壤的内在矿化作用和大气降水中的氮是这些受干扰湿地中硝酸盐的重要来源，但目前尚不清楚是哪种氮源导致了氮向地表水的释放。我们将使用一种新的方法，基于15N和18O的双同位素方法，使用尚未在城市湿地生态系统中进行测试的方法，在土壤剖面深处采集的土壤水样本中区分来自降水的N和来自土壤的N。区分淋溶到地表水的土壤和大气氮源将对环境管理和政策产生重要影响。这项研究也将对城市生态学这一新兴领域做出贡献。这项研究将在新泽西州奥杜邦协会、新泽西州保护基金会、新泽西州/新泽西州步道会议、新泽西州水资源研究所和Raritan BayKeeper等组织的出版物上以文章的形式向公众传达，这些组织都在城市化地区大力参与湿地的管理和保护。

AbstractProposal: DEB 0507973PI: Ehrenfeld, JoanInstitution: RutgersHuman activities, in particular fossil fuel combustion and fertilizer production, are adding vast quantities of nitrogen (N) to ecosystems. This excess N causes numerous environmental problems, including eutrophication, hypoxic coastal waters, loss of species diversity, and drinking water toxicity. Wetland systems typically have a high capacity to retain N because their wet soils promote denitrification, a soil process which converts nitrate to nitrogen gases. Wetlands in urban areas, however, may not have the same ability to remove N because hydrological alterations resulting from urbanization make urban wetlands drier than they have been historically, thus inhibiting the N-removing process of denitrification. Although it is known that both intrinsic soil mineralization and N from atmospheric deposition are important sources of nitrate in these disturbed wetlands, it is not known which source of N contributes to the release of N to surface waters. We will use a novel method, based on a dual isotope approach using 15N and 18O, which has not yet been tested in urban wetland ecosystems, to distinguish between N from precipitation and N from soil in soil water samples collected deep in the soil profile. Distinguishing soil and atmospheric sources of N leached to surface waters will have important implications for environmental management and policy. This research will also be a contribution to the emerging field of urban ecology. The research will be communicated in articles for the general public in the publications of such organizations as the NJ Audubon Society, the NJ Conservation Foundation, the NY/NJ Trail Conference, the NJ Water Resources Research Institute, and the Raritan Baykeeper, organizations that are all heavily involved in the management and conservation of wetlands in urbanizing regions.