Collaborative research: A Real-time and Rapid Response Observing System for the Study of Physical and Biological Controls on Muddy Seabed Deposition, Reworking and Resuspension

合作研究：用于研究泥质海底沉积、改造和再悬浮的物理和生物控制的实时快速响应观测系统

• 批准号: 0536572
• 负责人: Carl Friedrichs
• 金额: $ 194.65万
• 依托单位: College of William & Mary Virginia Institute of Marine Science
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0536572&HistoricalAwards=false
• 关键词: Collaborative; research; Real; time; Rapid

P.I. Friedrichs, Carl (VIMS) Proposal #: 0536572Mean mail rating: 1.6 high/low: 1.0-2.0Mean panel rating: 1.6 high/low: 1.0-2.0PROJECT TITLE: A real-time and rapid response observing system for the study of physical and biological controls on muddy seabed deposition, reworking and re-suspensionProject SummaryControls on seabed erodability and suspended particle properties are the two largest unknowns limiting accurate prediction of fine sediment transport in muddy coastal environments. These two parameters are difficult to predict in large part because biological effects fundamentally impact them over short temporal and spatial scales, and the physical and biological effects rapidly feedback on each other. This study proposes to place real-time remote observing platforms at locations of contrasting benthic physical disturbance that are characterized by strong gradients in benthic ecology, seabed characteristics and suspended particle properties. A combination of acoustic and video imaging of the seabed and lower water column will, in real time, identify changes in biologic activity, deposition, erosion, suspended sediment properties and/or bedform evolution that, in turn, trigger or otherwise indicate changes in bed erodability. Rapid response cruises employing real-time shipboard surveys will track events, directly measuring the short time-scale evolution of erodability, key physical and geochemical properties, and biological activity and assemblages. Open source numerical modeling of bed evolution, erosion and deposition, and water column processes will be coupled to the observing effort and will fundamentally advance predictability of fine sediment transport. The proposed study area, which leverages significant real-time observing efforts underway in the York River estuary and Lower Chesapeake Bay, has key properties in common with energetic, high sediment load shelves around the world which play essential roles in the global sediment and carbon cycles. In such systems, the nature of benthic biological activity, suspended particle properties and associated biological-physical feedbacks are tied to evolving salinity fronts and spatial and temporal gradients in physical disturbance. This is also commonly the case along major estuaries in the US and worldwide. Regardless of the locale, prediction of fine sediment transport relies critically on understanding controls on bed erodability and particle settling. This proposal hypothesizes that the evolution of bed erodability and suspended aggregates of fine sediment is distinctly different under biologically vs. physically dominated conditions. This proposal predicts that with increased biological activity, bed erodability will be greater and decrease less strongly with depth, but suspended aggregates will be larger and stronger due to small-scale biological binding. Under physically dominated conditions, erodability will increase suddenly with deposition, but decrease more quickly with time and depth due to rapid consolidation. Under physical dominance, suspended aggregates/flocs will be smaller and weaker, have smaller fall velocities, and decrease in size with increased stress due to breakup by shear.

P.I. Friedrichs, Carl （VIMS）提案#:0536572平均等级：1.6高/低：1.0-2.0平均面板等级：1.6高/低：1.0-2.0实时快速响应观测系统，用于研究泥泞海底沉积、改造和再悬浮的物理和生物控制项目摘要海底可侵蚀性和悬浮颗粒特性的控制是限制在泥泞海岸环境中精确预测细沉积物运输的两个最大未知数。这两个参数很难预测，很大程度上是因为生物效应在短时间和空间尺度上对它们产生根本性影响，而且物理效应和生物效应会迅速相互反馈。本研究提出将实时远程观测平台放置在底栖生物生态、海底特征和悬浮粒子特性梯度强的底栖生物物理扰动对比位置。海底和下层水柱的声学和视频成像结合将实时查明生物活动、沉积、侵蚀、悬浮沉积物性质和/或河床演变的变化，这些变化反过来触发或以其他方式表明河床可蚀性的变化。采用实时船载调查的快速反应巡航将跟踪事件，直接测量可蚀性、关键物理和地球化学性质、生物活动和组合的短时间尺度演变。河床演化、侵蚀和沉积以及水柱过程的开源数值模拟将与观测工作相结合，并将从根本上提高对细沙输运的可预测性。拟议的研究区域利用了正在约克河河口和下切萨皮克湾进行的重要实时观测工作，与世界各地在全球沉积物和碳循环中发挥重要作用的充满活力、高泥沙负荷的大陆架具有关键特性。在这样的系统中，底栖生物活动的性质、悬浮粒子特性和相关的生物-物理反馈与不断变化的盐度前沿和物理扰动的时空梯度有关。这在美国和世界各地的主要河口也很常见。无论在什么地方，细粒沉积物输运的预测主要依赖于对河床侵蚀性和颗粒沉降控制的理解。该建议假设，在生物和物理主导条件下，细粒沉积物的床蚀性和悬浮聚集体的演变明显不同。该建议预测，随着生物活性的增加，河床可蚀性将越来越大，随着深度的增加而减弱，但由于小规模的生物结合，悬浮聚集体将越来越大，越来越强。在物理条件下，侵蚀性随沉积而突然增加，但由于固结迅速，侵蚀性随时间和深度的增加而迅速下降。在物理优势作用下，悬浮集料/絮凝体体积更小、强度更弱，下落速度更小，随着剪切破碎应力的增大，粒径减小。