International Research Fellowship Program: Coupled Hydrodynamic and Biogeochemical Processes of Submerged Aquatic Vegetation

Branco国际研究奖学金计划使美国科学家和工程师能够在国外进行9至24个月的研究。该计划的奖项提供了联合研究的机会，并利用国外独特或互补的设施、专业知识和实验条件。该奖项将支持Brett F.Branco博士与澳大利亚克劳利西澳大利亚大学的Carolyn Oldham博士合作的为期24个月的研究奖学金。沉水水生植被(SAV)改变了浅层系统中的流场和光、热、营养物质、氧和其他成分的垂直分布。这些耦合的物理、化学和生物动力学决定了SAV生态系统的功能、稳定性和复原力。然而，对SAV生态系统中的耦合过程缺乏机械性的理解和量化。这项工作的目的是1)识别和量化在各种浅层系统中影响营养物质、氧气等跨SAV冠层垂直运输的过程，以及2)确定运输过程对SAV冠层下养分循环效率的影响。这项工作是在西澳大利亚州的沿海和内陆水域进行的，代表着三种不同的水环境：河流(单向河道流)、沿海海湾(以波浪为主的振荡流)和浅水湖(风混合表层)。SAV冠层和上覆水之间的垂直质量交换速率将在野外使用荧光染料和15N标记的营养示踪剂研究进行测量。这项工作将产生：1)研究SAV生态系统中物理、化学和生物耦合过程的方法，2)作为系统能量和能量耗散函数的SAV冠层间质量传递的量化，3)作为植物吸收速率和物理运输过程的函数的养分循环效率的量化，4)光纤荧光传感器在水生系统中的新应用，以及5)确定在确定SAV生态系统稳定性和弹性方面的重要对。

0601917BrancoThe International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-four-month research fellowship by Dr. Brett F. Branco to work with Dr. Carolyn Oldham at University of Western Australia in Crawley, Australia.Submerged aquatic vegetation (SAV) alters the flow field and vertical distribution of light, heat, nutrients, oxygen and other constituents in shallow systems. These coupled physical, chemical and biological dynamics determine SAV ecosystem function, stability and resiliency. However, mechanistic understanding and quantification of coupled processes in SAV ecosystems is lacking. The purposes of this work are to 1) identify and quantify the processes that affect the vertical transport of nutrients, oxygen, etc. across SAV canopies in a variety of shallow systems and 2) determine the impact of the transport processes on the recycling efficiency of nutrients below the SAV canopy. This work is being performed in coastal and inland waters of Western Australia representing three distinct aquatic environments: a river (unidirectional channel flow), a coastal bay (wave-dominated oscillatory flow) and a shallow lake (wind-mixed surface layer). Rates of vertical mass exchange between SAV canopies and overlying water will be measured in the field using fluorescent dye and 15N-labeled nutrient tracer studies. This work will produce: 1) a methodology for studying the coupled physical, chemical and biological processes in SAV ecosystems, 2) quantification of mass transfer across the SAV canopy as a function of system energy and energy dissipation, 3) quantification of nutrient recycling efficiency as a function of plant uptake rates and physical transport processes, 4) a new application for fiber optic fluorescent sensors in aquatic systems, and 5) identification of significant couples in determining SAV ecosystem stability and resiliency.