The impact of Hurricane Maria on the mesophotic reefs of southwest Puerto Rico

2017年9月20日，强飓风“玛丽亚”给波多黎各岛造成了毁灭性打击。陆地和海洋生态系统都受到了严重影响。这种强大而罕见的天气事件为研究极端自然力量对珊瑚礁的影响提供了机会。研究小组将集中研究中鳍珊瑚礁或“暮光地带珊瑚礁”，它们在多样性和美丽方面可与浅水珊瑚礁相媲美。中孔珊瑚生态系统是在30至100米深度之间发现的珊瑚礁，被认为是衰落的浅水珊瑚礁的避难所，因为它们进一步远离人为和自然干扰。飓风玛丽亚是那些罕见的、高强度的扰动事件之一，它甚至可以影响那些更深的、中深水的珊瑚礁。调查人员使用预先部署的海洋仪器和先前收集的生态数据来测量飓风玛丽亚对可能受到庇护的中鞘珊瑚礁的影响。研究人员将通过比较预先建立的浅层和中层珊瑚礁样带的照片数据来记录飓风对珊瑚礁群落的影响。错位的珊瑚将被用来测试极端天气事件影响关键物种种群连通性的能力。放射性同位素分析将用于确定从中藻礁收集的沉积物的来源。调查人员将根据飓风玛丽亚通过之前、期间和之后记录的物理条件来解释上述所有数据。该项目将涉及一个由五名研究人员组成的跨学科小组和一名来自西班牙裔服务机构的研究生的合作。调查人员将把调查结果散发给自然资源管理机构，并将利用当地媒体和组织外联活动，向当地社区通报飓风对珊瑚礁的影响。主要飓风玛丽亚在波多黎各南海岸的登陆提供了一个独特的机会来研究它对岛屿大陆架边缘珊瑚礁生态系统的影响（~25至70-80米深）。强大的天气系统可能引发了沉积物、浊度、陆源物质和底栖生物的大规模离架运输，影响了整个陆架边缘底栖生态系统。它也构成了一个前所未有的自然实验，珊瑚群可能被移走并移植到更深的区域，允许测试与深层避难所模型和浅层和中孔珊瑚礁之间的联系有关的各种假设。研究人员将通过以下方式评估作为岛坡介孔珊瑚礁深礁避难假说基础的生态系统稳定性：A)在浅海和中深水站预先建立的地点重复高分辨率的照片样带，b)记录移位/受损底栖生物分类群的类型和程度，c)通过浅海珊瑚向更深的深度位移来检查飓风辅助垂直连通性的可能性，d)通过沉积物样本的放射性同位素分析来测量陆源物质最近可能输入中深水的可能性，以及，e)将上述所有观测结果与玛丽亚飓风之前、期间和之后在现场测量的实际物理条件联系起来。

Major Hurricane Maria, on 20 September 2017, delivered a devastating blow to the island of Puerto Rico. Both terrestrial and marine ecosystems were heavily impacted.  This powerful and rare weather event provides an opportunity to examine the effects of extreme physical forces on coral reefs. The research team will concentrate on the mesophotic reefs or "twilight zone reefs", which rival shallow water coral reefs in diversity and beauty.  Mesophotic coral ecosystems are reefs found between 30 and 100 m depth, and are thought to serve as refugia for the declining shallow water coral reefs because they are further removed from anthropogenic and natural disturbances. Hurricane Maria is one of those rare, high-magnitude disturbance events that could affect even those deeper, mesophotic reefs. The investigators are positioned with pre-deployed oceanographic instruments and previously-collected ecological data to measure the effects of Hurricane Maria on the presumably sheltered, mesophotic reefs. The investigators will document the hurricane effects on the reef communities by comparing photographic data from pre-established transects at shallow and mesophotic reefs. Misplaced corals will be used to test the capacity of extreme weather events to shape the population connectivity of key species. Radioisotope analysis will be used to identify the origin of sediments collected from the mesophotic reefs. The investigators will interpret all data described above in light of the physical conditions that were recorded before, during, and after the passage of Hurricane Maria. The project will involve the collaboration of an interdisciplinary team of five researchers and a graduate student from a Hispanic-serving Institution. The investigators will disseminate the results to Natural Resources Management Agencies and will use local media outlets and organize outreach events to inform local communities about the effects of hurricanes on coral reefs.The landfall of major Hurricane Maria on the south coast of Puerto Rico provides a unique opportunity to examine its impacts on an insular shelf margin reef ecosystem (~25 to 70-80 m depth).  The powerful weather system likely triggered major off-shelf transport of sediments, turbidity, terrigenous material and benthic organisms, affecting entire shelf margin benthic ecosystems. It also constitutes a unprecedented natural experiment where coral colonies were likely dislodged and transplanted to deeper areas, allowing to test various hypotheses related the deep refugia model and connectivity between shallow and mesophotic coral reefs. The investigators will assess the ecosystem stability that underlies the deep-reef refuge hypothesis of the insular-slope mesophotic reefs by: a) repeating high resolution photo-transects at pre-established sites at shallow and mesophotic stations, b) documenting the type and extent of displaced/damaged benthic taxa, c) examining the possibility of hurricane-assisted vertical connectivity through the displacement of shallow corals to deeper depths, d) measuring the potential recent input of terrigenous material to mesophotic depths by radioisotope analysis of sediment samples and, e) relating all the above observations to actual physical conditions, which were measured in situ before, during, and after Hurricane Maria.