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

2018年10月，极强飓风迈克尔袭击了佛罗里达州狭长地带，造成海岸线毁灭性破坏。记录这一破纪录的风暴在各种沿海环境中造成的破坏，如海滩、沙丘、海湾、障碍岛和沼泽，可以及时向沿海社区和资源管理者通报热带风暴的危险和频率。更好地对这些影响进行科学了解，并提高公众对这种风暴影响的认识和了解，在防灾方面起着至关重要的作用。这项研究涉及在佛罗里达海岸一个通常受到小潮范围影响的地区收集样本并进行测量。沉积物和大型动物样本将通过岩心采集，并沿着佛罗里达州南部阿帕拉契科拉湾辐射出来的两个横断面进行抓取采样，最后到达屏障岛屿近海。将对样带的地面部分进行其他表征，以记录沙丘的形态变化以及名义上的地面和浅水环境的海拔变化。为了在地层记录中记录风暴沉积的保存潜力，将对横断面进行两次采样。风暴过后尽快打一次，六个月后打一次。这项研究的数据和结果，结合向广大沿海社区传播该项目的结果，将有助于评估与沿海地区有关的风险的公众和机构，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对这一重大自然灾害的复原力。这项研究利用这一难得的机会，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。表层沉积物和沉积物岩心沿两条流入阿巴拉契科拉湾的河流沿两条横断面收集，横断面从障碍岛的海面延伸到沿海沼泽。将利用堰塞岛、屏障后、海湾和滨海沼泽的沉积岩心来建立风暴沉积的区域尺度特征。将进行两次实地抽样，第一次是在风暴影响后不久，第二次是大约6个月后，目的是调查风暴沉积物的保存情况。沿海沼泽和沿海湖泊或天坑等低能量(即小潮)环境中极端飓风的风暴沉积已被广泛用于重建古飓风记录，从而提供了关于气候和风暴强度如何随时间变化的宝贵见解。此外，还将审查在往往会抹去这些记录的过程(如生物扰动和侵蚀)下，对非常薄的风暴沉积物的保存情况。由于风暴沉积在现有地貌特征之上的层层沉积物构成了海岸沼泽获得海拔的主要机制，像飓风迈克尔这样的强风暴可能在抗击由于海平面上升而淹没沼泽和其他沿海环境方面发挥重要作用。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.