Microfossil-based Approach to Estimate Hurricane Intensity from the Sedimentary Record

从沉积物记录中估算飓风强度的基于微化石的方法Jeff Donnelly，伍兹霍尔海洋研究所迄今为止，我们对飓风活动如何随时间变化以及未来如何变化的理解受到短暂的仪器和历史记录的阻碍。飓风在沿海沉积物中留下的沉积物为这一记录的延续提供了一种手段。风暴潮和与飓风有关的波浪经常在盐沼和沿海池塘中沉积存款沙子。经过数百至数千年的飓风形成的沉积物，随后被盐沼泥炭覆盖，形成了一个条形码状的沙和泥存款，为了解飓风的频率提供了线索。然而，我们对过去这些风暴的强度知之甚少。飓风期间沙子存款的厚度和沙粒的大小经常被用来估计飓风的强度，但这种方法是不完美的，因为沙子的大小和飓风沉积的厚度可能在很大程度上取决于可供运输的沉积物的数量。我们计划使用一种生活在所有海洋环境中的叫做有孔虫的小生物来确定过去飓风沉积在新英格兰盐沼中的沉积物来自何处。这些生物是独一无二的，因为它们生活在离岸的一定深度范围内，因此在过去的飓风沉积物中找到它们将有助于我们确定沙子在海洋中被挖掘的深度。鉴于更强烈的飓风会导致更高的海浪，能够从更深的水域挖掘沉积物，在飓风引起的沉积物中发现的深水有孔虫组合将表明更强烈的风暴。为了检验我们的假设，我们将使用飓风登陆新英格兰南部的历史记录，以确定是否有孔虫从不同的水深，沉积在盐沼，反映已知的飓风强度。一旦这种方法得到测试，我们就可以用它来估计数千年前沙层中有孔虫的飓风强度。飓风强度随时间的变化将提供重要的基线信息，有助于阐明气候对飓风强度的控制作用。这项工作的结果将有助于沿海资源管理人员、减灾管理人员和决策者，并使这些群体能够就适当的管理做法和监管战略作出知情的决定。其他利益攸关方（沿海区管理人员、生境恢复团体、土地管理人员、与风险管理有关的商业利益集团、沿海财产所有者和沿海科学家）将受益于该项目的成果。

MICROFOSSIL-BASED APPROACH TO ESTIMATE HURRICANE INTENSITY FROM THE SEDIMENTARY RECORD Jeff Donnelly,Woods Hole Oceanographic InstitutionTo date our understanding of how hurricane activity has changed over time and how it may change in the future is hampered by the short instrumental and historical record. Sand deposits left behind by hurricanes in coastal sediments provide a means of extending this record. Storm surge and waves associated with hurricanes often deposit sand in salt marshes and coastal ponds. Over hundreds to thousands of years hurricane-induced deposits are laid down and subsequently covered by salt marsh peat creating a barcode-like deposit of sand and mud that provides insight into hurricane frequency. However, we know little regarding the intensity of these past storms. The thickness of the sand deposit and size of sand grains transported during the hurricane has often been used to estimate how intense the hurricane was, but this method is imperfect because sand size and thickness of the hurricane deposits may be largely controlled by the amount of sediment available for transport. We plan to use a small organism called foraminifera that live in all marine environments, to determine where sediment deposited in New England salt marshes by past hurricanes is coming from. These organisms are unique because they live in certain depth ranges offshore, so finding them in past hurricane deposits will help us determine from how deep in the ocean the sand has been excavated. Given more intense hurricanes result in higher waves capable of excavating sediment from greater water depths, deeper water foraminifera assemblages found in hurricane-induced deposits will be indicative of a more intense storm. To test our hypothesis we will use the historic record of hurricane landfalls in southern New England to determine if foraminifera from different water depths, deposited within salt marshes, reflect known hurricane intensities. Once this method is tested we can use it to estimate hurricane intensity from foraminifera in sand layers going back thousands of years. The variation in hurricane intensity over time will provide important baseline information that will help elucidate the climatic controls on hurricane intensity. Results from this work will be useful to coastal resource managers, disaster mitigation managers, and policy makers and will enable these groups to make informed decisions regarding appropriate management practices and regulatory strategies. Other stakeholders (coastal zone managers; habitat restoration groups; land managers; business interests concerned with managing risk; coastal property owners and coastal scientists) will benefit from the results of this project.