RAPID: 2018 Hurricane Season: Sedimentological and Morphological Characteristics of Hurricane Michael Induced Storm Deposits in Apalachicola Bay

2018年10月，超强飓风迈克尔袭击了佛罗里达州狭长地带，对海岸线造成了毁灭性破坏。记录这场破纪录的风暴对海滩等各种沿海环境造成的破坏；沙丘;海湾;障壁岛;沼泽可以及时地向沿海社区和资源管理者通报高能热带风暴的危险和频率。更好地科学地了解这些影响并提高公众对这类风暴影响的认识和知识，在备灾方面发挥着至关重要的作用。这项研究包括收集样本，并沿着佛罗里达海岸的一个地区进行测量，该地区通常受小潮范围的影响。沉积物和大型动物样本将通过岩心采集，并沿着两条横断面采集样本，这两条横断面从佛罗里达州南部的阿巴拉契科拉湾向外辐射，一直延伸到堰洲岛的近海。将对样带的陆上部分进行其他表征，以记录沙丘的形态变化以及名义上的陆上和浅水环境的海拔变化。为了在地层记录中记录风暴沉积物的保存潜力，将对样带进行两次采样。一次是在风暴过后尽快，另一次是在六个月后。本研究的数据和发现，结合项目结果向更大范围的沿海社区传播，将有助于公众和机构评估与沿海地区相关的风险，了解强风暴对各种沿海环境的影响，从而更好地准备和了解这一重大自然灾害的复原力。本研究利用难得的机会，系统地记录了飓风迈克尔沿阿巴拉契科拉湾海岸产生的沉积记录。地表沉积物和沉积物岩心是沿着两条横断面收集的，这两条横断面从堰洲岛向海延伸到流入阿巴拉契科拉湾的两条河流沿岸的沼泽。将利用堰洲岛、后堰洲、海湾和沿海沼泽的沉积物岩心建立风暴沉积的区域尺度特征。将进行两次实地采样活动，第一次是在风暴影响后不久，第二次是在大约6个月后，目的是调查风暴沉积物的保存情况。极端飓风在低能量（即微潮）环境（如沿海沼泽和沿海湖泊或天坑）中的风暴沉积物已被广泛用于重建古飓风记录，从而为气候和风暴强度如何随时间变化提供了有价值的见解。此外，面对可能抹去这些记录的过程（例如，生物扰动和侵蚀），将研究通常非常薄的风暴沉积物的保存。由于在现有地貌特征之上的沉积层的风暴沉积构成了沿海沼泽抬升的主要机制，因此像飓风迈克尔这样的强风暴可能在应对因海平面上升而淹没的沼泽和其他沿海环境方面发挥重要作用。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

An extremely strong Hurricane Michael hit the Florida Panhandle in October 2018 and caused devastating destruction along the coastline. Documenting damage by this record-breaking storm in various coastal environments, such as beaches; dunes; bays; barrier islands; and marshes, in a timely fashion, can inform the coastal community and resource managers about the dangers and frequency of energetic tropical storms. A better scientific understanding of these impacts and raising public awareness and knowledge of such storm impacts plays a crucial role in hazard preparation. This research involves collecting samples and making measurements along an area of the Florida coast subject normally to microtidal ranges. Sediment and macrofaunal samples will be collected via cores and grab sampling along two transects radiating out of Apalachicola Bay in southern Florida and ending in the sea offshore of the barrier islands. Other characterization of subaerial parts of the transects will be carried out to document morphological changes in dunes and changes in elevation of nominally subaerial and shallow subaqueous environments. To document the preservation potential of storm deposits in the stratigraphic record, transects will be sampled twice. Once as soon as possible after the storm and once six months later. Data and findings from this study, in combination with dissemination of the results of the project to the greater coastal community, will help the public and institutions that assess risk associated with coastal areas, understand the impacts of strong storms on a wide variety of coastal environments resulting in better preparation and knowledge of resiliency for this significant natural hazard.This study takes advantage of the rare opportunity to systematically document the sedimentary record produced by Hurricane Michael along the Apalachicola Bay coast. Surface sediment and sediment cores are collected along two transects extending from seaward of the barrier islands to the coastal marshes along the two rivers that discharge into Apalachicola Bay. Sediment cores from the barrier islands, back-barrier, bay, and coastal marsh will be used to establish regional scale characteristics of storm deposits. Two field sampling campaigns will be conducted, with the first one shortly after the storm impact and the second one roughly 6 months later with the goals of investigating the preservation of the storm deposits. Storm deposits by extreme hurricanes in low-energy (i.e., microtidal) environments, e.g., coastal marsh and coastal lakes or sinkholes, have been broadly used to reconstruct paleo-hurricane records, thereby providing valuable insights to how climate and storm strength have changed with time. Furthermore, preservation of, often, very thin storm deposits in the face of processes that tend to erase these records (e.g., bioturbation and erosion) will be examined. Because storm deposits of layers of sediment on top of existing geomorphic features constitutes a major mechanism for coastal marshes to gain elevation, strong storms, like Hurricane Michael, likely play an important role in combating the drowning of marshes and other coastal environments due to sea-level rise.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.