Mississippi River Flood of 2008: Flood-Pulsed Experiments of Coastal Ecosystem Dynamics

2008 年密西西比河洪水：沿海生态系统动力学的洪水脉冲实验

• 批准号: 0833225
• 负责人: John White
• 金额: $ 9.99万
• 依托单位: Louisiana State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-15 至 2009-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0833225&HistoricalAwards=false
• 关键词: Mississippi; River; Flood; 2008; Pulsed

This SGER project will examine how river flood pulsing controls freshwater residence time in coastal wetland basins of Louisiana, and how this control regulates biogeochemical processing of nitrogen (N). The central hypothesis is that the pulsed event of river floods will decrease N retention and removal by wetlands (via denitrification) by drastically decreasing water residence times in entire wetland basins. This, in turn, will lead to increased N loading to the Gulf of Mexico, where anthropogenic N loading has long been implicated in coastal hypoxia and the Northern Gulf Dead Zone. It will take advantage of The Mississippi River flood of 2008, which will be one of the largest pulses of freshwater for wetlands in coastal Louisiana in almost a century. This study will use managed river diversions into the study basins to examine this relationship between freshwater inputs and nitrogen retention.This research will provide ecosystem managers, who manage valuable, large wetland systems like the Mississippi River Delta and the Florida Everglades, with critical water quality information. One management goal is to prevent excess N from reaching the coastal ocean where many economically important fisheries are located and where excess N causes toxic algal blooms, low dissolved oxygen, and massive fish kills. This experiment will also provide important data on how well coastal wetlands respond to very large pulses of freshwater.

该SGER项目将研究河流洪水脉冲如何控制路易斯安那州沿海湿地流域的淡水停留时间，以及这种控制如何调节氮（N）的地球化学过程。 中心的假设是，脉冲事件的河流洪水将减少氮的保留和去除湿地（通过反硝化），大大减少水的停留时间在整个湿地流域。 这反过来又会导致墨西哥湾的氮负荷增加，在那里，人为的氮负荷长期以来一直与沿海缺氧和北方海湾死区有关。 它将利用2008年的密西西比河洪水，这将是近世纪来路易斯安那州沿海湿地最大的淡水脉冲之一。本研究将采用有管理的河流改道进入研究流域，以研究淡水输入和氮保留之间的关系。本研究将为生态系统管理人员提供关键的水质信息，这些管理人员管理着宝贵的大型湿地系统，如密西西比河三角洲和佛罗里达大沼泽地。 一个管理目标是防止过量的氮进入沿海海洋，那里有许多经济上重要的渔业，过量的氮会导致有毒藻类大量繁殖，溶解氧低，大量鱼类死亡。 这项实验还将提供重要的数据，说明沿海湿地如何应对非常大的淡水脉冲。