SGER: The Impact of Extreme Flooding on Mussel and Microbial Nutrient Dynamics at the Water-Sediment Interface

SGER：极端洪水对水-沉积物界面的贻贝和微生物营养动态的影响

• 批准号: 0844112
• 负责人: Craig Just
• 金额: $ 7.56万
• 依托单位: University of Iowa
• 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: 2008-09-15 至 2009-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0844112&HistoricalAwards=false
• 关键词: SGER; Impact; Extreme; Flooding; Mussel

Introduction: This proposal is prepared in response to the devastating floods in Eastern Iowa and nearlythe entire Upper Mississippi River (UMR) basin during May-July 2008. In UMR Pool 16, above Lock andDam 16 at Muscatine, Iowa, waters abruptly rose from a highly managed stage of approximately 10 feetto 20 feet and then to nearly 24 feet from May-June 2008. This historic flood event coincided withintense spring cultivation and nutrient application activities in the heavily farmed landscape of theUpper Midwest resulting in a significant pulse of agricultural contaminants to the UMR system. This hasled scientists to predict an almost unprecedented delivery of sediment and nutrients to Pool 16, thebroader Mississippi River and the Gulf of Mexico.This event presents a unique, and short-lived, opportunity to test scientific hypotheses related to ahighly perturbed, large river ecosystem. This ecosystem of braided channels and natural backwaters isalready known to inadequately process nutrients such as nitrate to the degree required to protect theGulf from hypoxic episodes. Extreme, flood-related sediment deposition almost certainly impacts thenutrient processing cycle in the short and long term. It is also known that mussels and bacteria play amajor role in nutrient cycling in the broad food web containing phytoplankton, zooplankton, microzooplankton,dissolved & particulate organic matter, and benthos. Given this confluence of events, andthe importance of understanding nutrient cycling, we wish to test the following hypothesis:Intense deposition of particulate organic matter from extreme flooding alters the freshwater mussel andmicrobial food webs through physical and chemical means.Immediate Need: The principal investigators feel this hypothesis can only be tested via the quickresponseSmall Grants for Exploratory Research (SGER) funding mechanism since the highly perturbedecosystem in question is actively returning to more steady-state conditions. The research team must bedeployed very soon to study the perturbed nitrogen cycling rates such that comparisons with baselinenitrogen processing rates can be made in the future.Broader Impacts: Floods occur around the world on a regular basis, but the frequency and extremity ofthese events will increase given the influence of global climate change. This research will contribute tothe development of a ?theory of floods? that is proposed by colleagues at the University of Iowa. Thistheory will seek to unify research related to hydrology, ecology, socio-economic, environmental andhuman consequences and influences on flooding. The impact of such research can be expressed inbillions of dollars, millions of acres of habitat, thousands of species, and centuries of human enjoyment.Intellectual Merit: This research will expand our knowledge of large river nutrient processing dynamicsresulting from extreme flooding events and during baseline moments. Abrupt changes in nutrientloading and extreme shifts in algal compositions can influence food quality which may adversely affectdesirable and invasive freshwater mussels. This work will further characterize the relation betweennutrient conditions and food quality for mussels and other biota in an important reach of the UpperMississippi River. Water quality, nutrients, and their effects of biological processes are key managementconcerns in the Upper Mississippi River.

简介：本提案是为了应对 2008 年 5 月至 7 月期间爱荷华州东部和几乎整个密西西比河上游 (UMR) 流域的毁灭性洪水而制定的。在爱荷华州马斯卡廷 16 号船闸和 16 号水坝上方的 UMR 16 池中，水位从 2008 年 5 月至 6 月突然从高度管理的约 10 英尺升至 20 英尺，然后升至近 24 英尺。这一历史性洪水事件与春季集中耕种， 中西部北部重度农耕地区的养分施用活动导致 UMR 系统出现大量农业污染物。这促使科学家们预测，沉积物和营养物质将向 16 号池、更广阔的密西西比河和墨西哥湾输送几乎前所未有的情况。这一事件提供了一个独特且短暂的机会来测试与高度扰动的大型河流生态系统相关的科学假设。众所周知，这种由辫状河道和天然回水组成的生态系统无法充分处理硝酸盐等营养物质，达到保护海湾免受缺氧事件所需的程度。与洪水相关的极端沉积物沉积几乎肯定会影响短期和长期的养分加工循环。人们还知道，贻贝和细菌在包含浮游植物、浮游动物、微型浮游动物、溶解和颗粒有机物以及底栖动物的广泛食物网中的营养循环中发挥着重要作用。考虑到这些事件的汇合以及了解养分循环的重要性，我们希望检验以下假设：极端洪水导致颗粒有机物的强烈沉积，通过物理和化学手段改变了淡水贻贝和微生物食物网。 迫切需要：主要研究人员认为，这一假设只能通过快速反应的小额探索性研究赠款（SGER）资助机制进行检验，因为高度 相关的扰动生态系统正在积极恢复到更稳定的状态。研究小组必须尽快开始研究受干扰的氮循环速率，以便将来与基线氮处理速率进行比较。 更广泛的影响：世界各地经常发生洪水，但考虑到全球气候变化的影响，这些事件的频率和极端程度将会增加。这项研究将有助于“洪水理论”的发展。这是由爱荷华大学的同事提出的。该理论将寻求统一与水文学、生态学、社会经济、环境和人类对洪水的后果和影响相关的研究。此类研究的影响可以用数十亿美元、数百万英亩的栖息地、数千种物种和几个世纪的人类享受来表达。 智力价值：这项研究将扩展我们对极端洪水事件和基线时刻产生的大河流养分处理动态的了解。营养负荷的突然变化和藻类成分的极端变化会影响食品质量，从而可能对所需的入侵性淡水贻贝产生不利影响。这项工作将进一步描述密西西比河上游重要河段的贻贝和其他生物群的营养条件与食物质量之间的关系。水质、营养物及其生物过程的影响是密西西比河上游的关键管理问题。