RAPID: Assessing the role of hurricanes and microbes in enhancing coastal sediment accumulation

超过6000万美国人生活在墨西哥湾和大西洋沿岸。美国的这些地区最容易受到飓风和海平面上升的影响。然而，稳定海岸线和增加泥沙堆积可以减少这些危险。这项研究探索了微生物如何影响特克斯和凯科斯群岛上的一个无人居住的小岛龙涎岛上的这些过程。2022年9月，飓风菲奥娜在该岛附近经过。这项研究考察了飓风过后，微生物如何稳定泻湖和沿海地区的沉积物。这项研究的结果将通过与特克斯和凯科斯群岛环境和沿海资源部的伙伴关系与当地社区分享。这项研究还为可帮助社区稳定其海岸线的干预措施提供了概念证据。这将增强对海平面上升和飓风强度增加的抵御能力。该项目的教育影响范围更广，包括科罗拉多大学的一名研究生和加州大学伯克利分校的一名博士后参加了采样旅行。这项研究跟踪了2022年9月飓风菲奥娜在靠近小龙涎礁时发生的微生物垫子沉积物稳定和飓风角砾岩胶结的反应。2022年6月的前一个野外季节的观测提供了飓风前的基线。拟议的工作包括：(1)溶解的O2、H_2S和pH的微电极剖面，以跟踪MAT中的地球化学梯度的重建和16S rRNA基因测序，以将群落恢复与我们在IRMA之前/之后和FIFONA之前的观察结果进行比较；(II)安装小型表面高度表设备，以定量跟踪一系列地点的MAT生长的净厚度；(3)重复的现场显微镜观察和短期捕获和结合实验，以确定MAT对增加的沉积物的反应是否随时间的推移是相同的(即，输送新的沉积物是垂直吸积的主要要求)，还是随着生态系统的恢复，MAT的反应发生变化(即，飓风对微生物生态系统的扰动与沉积物的输送同样重要)；和(4)现场飓风角砾岩化实验，以测量岩化的时间尺度和存在的微生物活动。这项工作将在2023年的三个野外季节进行，允许对飓风扰动后第一年的岛屿响应进行短期(每日)和中期(长达数月)的观测。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。

Over 60 million Americans live along the coasts of the Gulf of Mexico and Atlantic. These regions of the United States are the most vulnerable to hurricanes and sea level rise. However, stabilizing coastlines and increasing sediment accumulation can reduce these hazards. This study explores how microbes affect these processes on Little Ambergris Cay, a small uninhabited island in the Turks and Caicos Islands. In September 2022, Hurricane Fiona passed near the island. This study examines how microbes stabilize sediment in both lagoonal and coastal settings after the hurricane. Results from this study will be shared with local communities through partnership with the Turks and Caicos Islands Department of Environment and Coastal Resources (DECR). This study also provides proof of concept for interventions that could help communities stabilize their coastlines. This would enhance resilience against sea level rise and increasing hurricane intensity. The project educational Broader Impacts include participation of a graduate student from University of Colorado and a postdoc from University of California, Berkeley in the sampling trips.This study tracks responses of microbial mat sediment stabilization and cementation of hurricane breccias that occur during the recovery from Hurricane Fiona, which passed close to Little Ambergris Cay as a Category 3 hurricane in September 2022. Observations from a prior field season in June 2022 provide a pre-hurricane baseline. Proposed work includes: (i) microelectrode profiles of dissolved O2, H2S, and pH to track re-establishment of geochemical gradients in mats and 16S rRNA gene sequencing to compare community recovery to our pre/post-Irma and pre-Fiona observations; (ii) installation of small-scale surface elevation table devices to quantitatively track net thickness of mat growth in a suite of locations; (iii) repeated in situ microscopy observations and short-term trapping-and-binding experiments to determine whether mat response to added sediment is the same over time (i.e., the delivery of new sediment is the primary requirement for vertical accretion) or if the mat response changes as the ecosystem recovers (i.e., the hurricane perturbation to the microbial ecosystem is as important as the delivery of sediment); and (iv) in situ hurricane breccia lithification experiments to measure the timescale of lithification and the microbial activity present. This work will be carried out over three field seasons during 2023, allowing both short-term (daily) and medium-term (months-long) observations of the island response during the first year following hurricane perturbation.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.