NERC-NSTC: Erosion in the deep ocean - the impact of the Kuroshio Current on the continental shelf and slope of Taiwan

NERC-NSTC：深海侵蚀——黑潮对台湾大陆架和斜坡的影响

• 批准号: NE/X003019/1
• 负责人: Uisdean Nicholson
• 金额: $ 10.32万
• 依托单位: Heriot-Watt University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 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=NE%2FX003019%2F1
• 关键词: NERC; NSTC; Erosion; deep; ocean

The global 'conveyor belt' of ocean currents are an important part of Earth's climate system, transporting heat and nutrients around the global oceans. They also transport large volumes of sediments and re-deposit these in large drifts in the deep oceans. These sediments then provide an important archive of the current systems that produced them, as well as changing temperatures and environmental conditions. In recent years, we have increasingly recognized that the large-scale eddies in the Earth's large surface currents, such as the Gulf Stream, also play an important role in the deep ocean. These eddies, which are equivalent to cyclones in the atmosphere, are concentrated at ocean fronts, and can cause deep erosion of the seabed - many hundreds of metres deep in some cases.The Kuroshio Current is one of these important surface current systems (associated with a front), that is a fundamental part of the ocean circulation system of the Pacific. Our recent work to the south of Taiwan, and offshore Japan, shows that this is a highly dynamic system which interacts with the complex seabed at an active margin (where two tectonic plates are colliding), deeply eroding and re-distributing sediment.In this project, we aim to understand the effect of the Kuroshio Current offshore Taiwan. We will use seismic reflection data, multibeam bathymetry data (proving high-resolution seabed maps) and core samples, to understand the impact of the current in a number of areas. We will specifically test how the current interacts with elevated tectonic ridges and whether it is capable of eroding deep channels across the continental shelf and slope. We will then investigate hazards associated with this deep erosion, including whether the removal of sediment from the plate boundary changes the stress state in the area, potentially with implications for earthquake magnitude and frequency - something that has never previously been tested - and whether the current destabilizes the continental slope, leading to underwater landslides and tsunamis. This project will also allow us to develop a new, long-term partnerships between our institutions in the UK, Germany and Taiwan, to expand this work in the future. The Kuroshio Current is relatively understudied but it is the ideal natural laboratory to understand the impact of ocean currents on continental margins, and address fundamental new questions about the links between the oceans and deep earth processes that have a major impact on human populations.

全球洋流“传送带”是地球气候系统的重要组成部分，在全球海洋周围输送热量和营养物质。它们还运输大量沉积物，并将这些沉积物重新沉积在深海的大漂流中。这些沉积物为当前产生它们的系统以及不断变化的温度和环境条件提供了重要的档案。近年来，我们越来越认识到，地球表面大流中的大尺度涡流，如墨西哥湾流，在深海中也发挥着重要作用。这些涡流相当于大气中的气旋，集中在海洋前缘，可对海底造成深度侵蚀，有时深达数百米。黑潮就是这些重要的表层海流系统之一（与锋），这是太平洋海洋环流系统的基本组成部分。我们最近在台湾南部和日本近海的工作表明，这是一个高度动态的系统，与活跃边缘（两个构造板块碰撞）的复杂海底相互作用，深度侵蚀并重新分布沉积物。项目的目的是了解黑潮对台湾近海的影响。我们将使用地震反射数据、多波束测深数据（提供高分辨率海底地图）和岩心样本，来了解洋流对多个地区的影响。我们将专门测试洋流如何与高架构造脊相互作用，以及它是否能够侵蚀横跨大陆架和斜坡的深水通道。然后，我们将调查与这种深度侵蚀相关的危害，包括从板块边界去除沉积物是否会改变该地区的应力状态，这可能会对地震震级和频率产生影响（这是以前从未测试过的），以及当前的破坏大陆坡的稳定，导致水下山体滑坡和海啸。该项目还将使我们能够在英国、德国和台湾的机构之间建立新的长期合作伙伴关系，以在未来扩大这项工作。黑潮洋流的研究相对较少，但它是了解洋流对大陆边缘影响的理想自然实验室，并解决有关对人类产生重大影响的海洋与地球深层过程之间联系的基本新问题。