Can extreme internal waves trigger turbidity currents and carbon transport in submarine canyons?

极端内波能否引发海底峡谷的浊流和碳迁移？

• 批准号: 2733940
• 金额: --
• 依托单位: University of East Anglia
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2733940
• 关键词: extreme; internal; waves; trigger; turbidity

Scientific background:Submarine canyons play a key role in the transport of sediment and carbon from shelf seas to the deep ocean by funnelling sediment-laden turbidity currents and cold-salty density currents down the continental slope. These currents are sporadic and the processes that trigger them poorly understood, so their overall contribution to global sediment and carbon budgets remains uncertain. One proposed triggering mechanism involves large-amplitude internal (subsurface) waves, which are generated by ocean tides and focused into submarine canyons. Internal waves increase near-bed current speed and particularly energetic internal wave events may resuspend enough sediment to form turbidity currents. Project objectives:1) Investigate how internal waves resuspend sediment and carbon.2) Identify triggering thresholds.3) Determine down-canyon sediment and carbon transport.Research methodology:You will analyse long-duration hydrodynamic, sedimentological and biogeochemical data from Whittard Canyon, a large branching submarine canyon system that incises the Celtic Sea continental shelf. Using autonomous ocean glider and acoustic Doppler current profiler (ADCP) mooring data, you will first map the spatial and seasonal variability of internal waves within the canyon to identify where and when triggering events are most likely. Then, using data from sediment traps and biogeochemical sensors, you will investigate the mechanisms by which internal waves resuspend sediment and carbon, identify triggering thresholds, and quantify down-canyon sediment and carbon transport. Finally, you will compare your results from Whittard Canyon with other canyon systems worldwide.

科学背景：海底峡谷通过汇合到大陆坡上沿着沉积物的浊流和冷 - 盐密度电流的漏斗，在从货架海洋到深海的沉积物和碳的运输中起关键作用。这些电流是零星的，并且触发它们的过程知之甚少，因此它们对全球沉积物和碳预算的总体贡献仍然不确定。一种提出的触发机制涉及大振幅内部（地下）波，这些波是由海潮产生的，并集中在海底峡谷中。内波增加了近床的速度，尤其是能量的内波事件可能会恢复足够的沉积物以形成浊流。项目目标：1）研究内部波如何重悬沉淀物和碳。2）识别触发阈值。3）确定倾斜的沉积物和碳传输。研究方法：您将分析长期水力动力学，沉积学和生物地质学数据，来自惠特德峡谷，惠特德峡谷，一个大型的分支海底峡谷系统，它破坏了凯尔特海洋大陆架。使用自主海洋滑翔机和声学多普勒电流探测器（ADCP）系泊数据，您将首先绘制峡谷内部波的空间和季节性变异性，以识别最有可能触发事件的何时何地。然后，使用来自沉积物陷阱和生物地球化学传感器的数据，您将研究内波重悬的沉积物和碳的机制，识别触发阈值，并量化下汇的沉积物和碳转运。最后，您将将Whittard Canyon的结果与全球其他峡谷系统进行比较。