A missing link between continental shelves and the deep sea: Have we underestimated the importance of land-detached canyons?

海底峡谷被认为是大陆架和深海之间沉积物、营养物、有机碳和污染物转移的全球重要通道。然而，直接量化海底峡谷中颗粒物通量的努力只集中在少数直接连接到河流或沿海沿岸的细胞的峡谷1。由于长期以来的范例，峡谷的头部位于100公里的海岸是静止的沉积物输送方面，这些“陆地分离”的峡谷往往被忽视的水动力监测，尽管占超过四分之三的世界各地的海底峡谷>9000 2。如果没有测量，我们就无法量化陆地分离峡谷中的颗粒通量，从而暴露出对全球沉积物路径系统和大陆架深海交换的理解方面的一个重大空白。在凯尔特边缘2（距离海岸>250公里）的Whittard峡谷进行的新测量记录了强大的浊流，其频率和幅度与主要陆地连接峡谷中报告的相似，令人惊讶。这些新的结果挑战了长期以来的范式，但问题仍然是什么触发了这些流动，它们运输的材料量，以及它们掩埋自然沉积物和人为污染物的效率。这个项目将利用来自Whittard峡谷的新数据来解决这些重要问题。

Submarine canyons are assumed to be globally-significant conduits for the transfer of sediment, nutrients, organic carbon and pollutants between continental shelves and the deep sea. However, efforts to directly quantify contemporary particulate fluxes through submarine canyons have focused solely on a handful of canyons that directly connect to rivers or coastal littoral cells1. Because of the long-standing paradigm that canyons whose heads lie 100s of km from shore are quiescent in terms of sediment transport, these 'land-detached' canyons have often been overlooked by hydrodynamic monitoring; despite accounting for more than three quarters of the >9000 submarine canyons worldwide2. Without measurements, we cannot quantify particulate fluxes in land-detached canyons, exposing a major gap in understanding of global sediment routing systems and shelf to deep-sea exchanges. New measurements in the Whittard Canyon, Celtic Margin2 (>250 km from shore) recorded powerful turbidity currents, of a surprisingly similar frequency and magnitude to those reported in major land-attached canyons3. These new results challenge the long-held paradigm, but questions remain concerning what triggers these flows, the volumes of material they transport, and the efficiency by which they bury natural sediments and anthropogenic pollutants. This project will tackle these important questions, using new data from Whittard Canyon.