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

2017年9月20日，大型飓风玛丽亚对波多黎各造成毁灭性打击。陆地和海洋生态系统都受到严重影响。 这种强大而罕见的天气事件为研究极端物理力量对珊瑚礁的影响提供了机会。研究小组将集中研究中光珊瑚礁或“暮光区珊瑚礁”，它们在多样性和美丽性方面可与浅水珊瑚礁相媲美。 中光珊瑚生态系统是在30米至100米深处发现的珊瑚礁，被认为是衰落的浅水珊瑚礁的避难所，因为它们远离人为和自然干扰。飓风玛丽亚是罕见的高强度扰动事件之一，甚至可能影响那些更深的中光珊瑚礁。调查人员配备了预先部署的海洋学仪器和先前收集的生态数据，以测量飓风玛丽亚对可能受到庇护的中光珊瑚礁的影响。调查人员将通过比较浅水和中光珊瑚礁预先确定的断面的摄影数据，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塑造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光珊瑚礁收集的沉积物的来源。 调查人员将根据飓风玛丽亚过境之前、期间和之后记录的物理条件解释上述所有数据。 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。调查人员将向自然资源管理机构传播调查结果，并将利用当地媒体渠道和组织外联活动，向当地社区通报飓风对珊瑚礁的影响。大型飓风玛丽亚在波多黎各南海岸的登陆，为研究其对岛屿大陆架边缘珊瑚礁生态系统（~25至70-80米深度）的影响提供了一个独特的机会。 强大的天气系统可能引发沉积物、混浊物、陆源物质和底栖生物大量迁移到大陆架外，影响到整个大陆架边缘的底栖生态系统。它也构成了一个前所未有的自然实验，珊瑚群落可能被驱逐并移植到更深的地区，允许测试各种假设有关的深避难所模型和浅水和中光珊瑚礁之间的连接。调查人员将通过以下方式评估作为岛坡中光珊瑚礁深礁避难所假设基础的生态系统稳定性：（a）在浅水和中光观测站预先确定的地点重复进行高分辨率照片断面，（B）记录移位/受损的底栖生物分类群的类型和范围，（c）通过将浅水珊瑚移位到更深的深度，研究飓风促成的垂直连通性的可能性，d）通过沉积物样品的放射性同位素分析，测量陆源物质向中光深度的潜在近期输入; e）将所有上述观测结果与实际物理条件联系起来，这些条件是在飓风玛丽亚之前、期间和之后现场测量的。

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.