90Y/90Sr and 234Th/238U disequilibria: Using dual chronometers to measure the effect of invasive dreissenid mussels on particle dynamics in Lake Michigan.

90Y/90Sr 和 234Th/238U 不平衡：使用双计时器测量入侵的德莱森贻贝对密歇根湖粒子动力学的影响。

• 批准号: 1030558
• 负责人: James Waples
• 金额: $ 39.05万
• 依托单位: University of Wisconsin-Milwaukee
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1030558&HistoricalAwards=false
• 关键词: 90Y; 90Sr; 234Th; 238U; disequilibria

In this project, researchers at the University of Wisconsin at Milwaukee will continue their research into the fluxes, pathways and residence times of particles and their associated nutrients and energy in nearshore waters of Lake Michigan. Their overall objective is to further explore the use of dual fast process chronometers (90Y/90Sr) and 234Th/238U disequilibria) as tracers of rapid particle dynamics. In Lake Michigan, dreissenid mussels now dominate these nearshore dynamics and the project objectives, therefore, focus on this influence. There are three specific objectives: (1) Examine what effect the in situ benthic mussel population density has on in situ particle (nutrient) removal from the water column. (2) Examine what effect an in situ benthic mussel population has on in situ particle (nutrient) removal under seasonally changing thermal conditions. (3) Examine the residence time of mussel-filtered particles (in the form of feces and pseudo-feces) and the inventory of 90Y and 234Th on the nearshore non-depositional lake bed. Broader Impacts: Coastal zones are under increasing nutrient and toxic stress, and developing and improving techniques for tracking suspended materials on short time-scales will have broad applicability in both Great Lakes and marine biogeochemistry. Understanding the transport of contaminants is also relevant to the heightened concerns over water security, particularly in the Great Lakes from which nearly 40 million people draw drinking water. The utility of radionuclides as tracers for following and quantifying environmental processes is an expanding field, and novel radionuclide techniques have wide potential application in limnology, oceanography, ground water and surface water hydrology, and terrestrial-aquatic system coupling. These tools are an essential component of the environmental research toolbox. Relatively few laboratories in the Great Lakes region are capable of making radiometric measurements; improving this capability has regional importance.

在这个项目中，威斯康星大学密尔沃基分校的研究人员将继续他们对密歇根湖近岸水域中颗粒物及其相关营养物质和能量的通量、路径和停留时间的研究。他们的总体目标是进一步探索使用双快过程计时器(90Y/90Sr和234/238U不平衡)作为快速粒子动力学的示踪剂。在密歇根湖，淡水贻贝现在主导着这些近岸动态和项目目标，因此，重点关注这种影响。具体目标有三个：(1)考察现场底栖贻贝种群密度对水体中颗粒物(营养物)原位去除的影响。(2)考察在季节变化的温度条件下，原位底栖贻贝种群对原位去除颗粒(养分)的影响。(3)考察贻贝过滤颗粒(粪便和假粪便)在近岸非沉积湖床上的滞留时间和90Y、234的存留时间。更广泛的影响：沿海地区受到越来越多的营养物质和有毒物质的胁迫，开发和改进在短时间尺度上追踪悬浮物质的技术将在五大湖和海洋生物地球化学方面具有广泛的适用性。了解污染物的运输也与人们对水安全的高度关切有关，特别是在五大湖地区，近4000万人从这些地区获得饮用水。放射性核素作为示踪剂用于跟踪和量化环境过程是一个不断发展的领域，新的放射性核素技术在湖泊学、海洋学、地下水和地表水水文学以及陆地-水系耦合方面具有广泛的应用潜力。这些工具是环境研究工具箱的重要组成部分。大湖区有能力进行辐射测量的实验室相对较少；提高这一能力具有区域重要性。