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

P.I. Friedrichs，Carl（VIMS）提案编号：0536572平均邮件评级：1.6高/低：1.0- 2.0平均面板评级：1.6高/低：1.0- 2.0项目标题：用于研究淤泥质海底沉积物的物理和生物控制的实时和快速反应观测系统，重新工作和重新-悬沙工程概述海底可蚀性和悬浮颗粒特性的控制是限制淤泥质海岸细颗粒泥沙输移准确预测的两个最大的未知因素环境.这两个参数在很大程度上难以预测，因为生物效应在很短的时间和空间尺度上对它们产生根本性影响，而且物理和生物效应迅速相互反馈。这项研究建议在海底物理扰动对比鲜明的地点放置实时远程观测平台，这些地点的特点是海底生态、海底特性和悬浮颗粒特性梯度很大。海底和下层水柱的声学和视频成像相结合，将真实的确定生物活动、沉积、侵蚀、悬浮沉积物特性和（或）底形演变的变化，这些变化反过来又触发或以其他方式表明河床可侵蚀性的变化。采用实时船上调查的快速反应巡航将跟踪事件，直接测量侵蚀性、关键物理和地球化学特性以及生物活动和组合的短时间尺度演变。河床演变、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，并将从根本上提高细泥沙输运的可预测性。拟议的研究区，利用显着的实时观测工作正在进行的约克河口和下切萨皮克湾，具有关键的共同属性与充满活力，高沉积物负荷货架在全球沉积物和碳循环中发挥重要作用。在这种系统中，底栖生物活动的性质、悬浮颗粒的特性和相关的生物-物理反馈与不断变化的盐度前沿以及物理扰动的空间和时间梯度有关。这也是常见的情况沿着主要河口在美国和世界各地。无论地点，预测细泥沙输运关键依赖于了解控制床的可蚀性和颗粒沉降。这一建议假设，床面可蚀性和细颗粒泥沙悬浮团聚体的演变是明显不同的生物与物理条件下占主导地位。这一建议预测，随着生物活动的增加，床层可蚀性将更大，并随深度下降不那么强烈，但由于小规模的生物结合，悬浮聚集体将更大，更强。在物理主导条件下，可蚀性随沉积而突然增加，但由于快速固结，可蚀性随时间和深度迅速下降。在物理主导下，悬浮聚集体/絮凝体将更小和更弱，具有更小的下降速度，并且由于剪切破碎而随着应力增加而减小尺寸。

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.