Dissertation Research: Nitrate Reduction at the Salt Marsh Groundwater Interface

9520819富含硝酸盐的安德森地下水可能是近岸生态系统的一个重要的非点源营养源。这种氮源的重要性将取决于排放的地点和从高地向沿海边缘输送地下水过程中发生的生物变化。潮间带湿地是北美东海岸潮间带地区引人注目的居住者。当地下水接触厌氧沼泽沉积物时，存在的硝酸盐可能会反硝化为氮或异化为铵。根据发生的过程，氮要么保存在系统内，要么输出到系统外。目前还没有方法可以同时量化和区分异化和反硝化。这项工作建议使用稳定的同位素技术和保守的示踪剂来确定异化和反硝化的速率，并将测量结果与季节性有机碳波动和净沼泽群落生产联系起来。

9520819 ANDERSON Groundwater enriched in nitrate may be a significant non-point nutrient source to near-shore ecosystems. The importance of this nitrogen source will depend upon the site of discharge and biological transformations that occur during transit of groundwater from uplands across the coastal margin. Intertidal wetlands are conspicuous occupants of intertidal areas throughout the eastern coast of North American. As groundwater contacts anaerobic marsh sediments, the nitrate present may undergo denitrification to nitrogen or dissimilation to ammonium. Depending upon which process occurs, nitrogen will either be conserved within or exported out of the system. There is no method currently available to simultaneously quantify and differentiate between dissimilation and denitrification. This work proposes using stable isotope technology along with conservative tracers to determine rates of dissimilation and denitrification and relate measurements to seasonal organic carbon fluctuations and net marsh community production.