RAPID: Storm-related sediment export during hurricanes Irma and Maria along the northwestern insular shelf of St. Croix, US Virgin Islands

2017年夏天袭击加勒比海的飓风“厄玛”和“玛丽亚”都是五级风暴，对许多岛屿造成严重破坏，不仅摧毁了大量民用基础设施，还影响了许多浅层海底环境。本研究项目收集时间紧迫的、短暂的数据，包括对美属维尔京群岛圣克罗伊岛凯恩湾侵蚀、沉积物再分配和珊瑚礁结构破坏的观察。之所以选择这个地点，是因为当飓风“厄玛”和“玛丽亚”达到最大强度时，它都在飓风中心或附近。它也是1989年另一次大飓风袭击的地点（即飓风雨果）。为本项目收集的数据也为雨果飓风收集了数据，可以进行比较，并对大型风暴对现代珊瑚礁系统中碳酸盐生成、生物侵蚀和沉积物输出的影响进行全面建模。将收集陆地和海洋摄影图像以及其他数据，以提供每次风暴的沉积物移动的高质量测量。这些数据，以及飓风雨果的历史数据，将用于模拟过去一个世纪该地区与风暴相关的沉积物运输。这项工作的广泛影响包括与美国地质调查局的研究人员建立伙伴关系，制作一个基于克服珊瑚礁建设误解的教育视频，以及提高对大风暴对珊瑚礁影响的认识，这将有助于了解和改善珊瑚礁管理。现代珊瑚礁中碳酸盐的产生和碳酸盐的循环是由于珊瑚和珊瑚藻类分泌方解石与生物和物理手段对珊瑚礁物理结构的破坏和去除之间的平衡。虽然该方程的生物学相关组成部分已被深入研究，但该方程缺少的一部分是沉积物输出，这是一个目前知之甚少和量化的参数。一组记录珊瑚礁系统沉积物输出的关键数据是在雨果飓风过后在美属维尔京群岛圣克罗伊岛的凯恩湾收集的。在岛上天气晴朗的情况下收集了额外的数据进行比较。这个新项目收集的数据与雨果飓风后收集的数据相似。它将允许对各种风暴进行定量比较，并对沉积物输出进行评估。目标将是描述从圣克罗伊岛西北岛架移走沉积物的特征。建模将由美国地质调查局的一名合作者进行，重点是确定在热带碳酸盐系统的珊瑚礁输出沉积物的大风暴期间，底部剪切与风暴潮的相对作用。

Hurricane Irma and Maria, both category 5 storms, that struck the Caribbean in the summer of 2017 caused severe damage to many islands not only destroying a significant amount of civil infrastructure but also impacting many shallow submarine environments. This research project collects time-critical, ephemeral data consisting of observations of erosion, sediment redistribution, and coral reef structure damage at Cane Bay on St Croix in the US Virgin Islands. This location was picked because it was at or near the center of both Hurricane Irma and Hurricane Maria when they were at their maximum strength. It is also the location of another major hurricane strike (i.e., Hurricane Hugo) in 1989. Data like that collected for the present project were also collected for Hurricane Hugo, allowing comparisons to be made and comprehensive modeling of the impact major storms have on carbonate production, bioerosion, and sediment export in a modern reef system. Land and marine photographic images, as well as other data will be collected to provide high quality measurements of sediment removal by each storm. These data, as well as historical data from Hurricane Hugo, will be used to model storm related sediment transport in the area over the past century. Broader impacts of the work include partnership with researchers at the US Geological Survey, production of an educational video based on overcoming reef-building misconceptions, and improving knowledge of the impacts of major storms on coral reefs which will help inform and improve reef management.Carbonate production and carbonate cycling in modern reefs is due to a balance between the secretion of calcite by corals and coralline algae and the breakdown and removal of the physical structure of the reef by biological and physical means. While the biologically related components of this equation have been intensively studied, a missing part of the equation is sediment export, a parameter that is presently poorly understood and quantified. A key set of data documenting sediment export in a reef system was collected in Cane Bay at St. Croix in the US Virgin Islands just after Hurricane Hugo. Additional data was collected during fair weather conditions on the island for comparison. This new project collects similar data to that collected after Hurricane Hugo. It will allow a quantitative comparison between the various storms and an assessment of sediment export. Goals will be to characterize sediment removal from the northwestern insular shelf of St. Croix. Modeling, to be carried out by a collaborator from the US Geological Survey, will be focused on determining the relative roles of bottom shear versus storm surge during major storms in exporting sediment from coral reefs in tropical carbonate systems.