RAPID: Collaborative Research: Unprecedented Hurricane Ian Nutrient and Organic Matter Inputs to Southwest Florida Coastal Waters

许多沿海系统正面临着持续发展和气候变化的威胁，包括飓风等极端天气事件的强度增加。这样的风暴现在比前几年更潮湿，因为温暖的大气层拥有更多的水分。因此，它们释放更多的降雨，并向沿海地区提供更多的营养物质和有机物质。这反过来又导致浮游植物大量繁殖，可能形成区域性“死亡区”或溶解氧很少或没有溶解氧的区域。2022年9月下旬袭击佛罗里达西南部的4级飓风伊恩（Hurricane Ian）导致沿海河口和佛罗里达西南部陆架沃茨大量营养物质和有机碳输入，并提供了一个机会来研究大型风暴扰动对沿海系统的影响，该系统正处于不断增加的沿海营养物质压力之下。这个快速项目的目标是检查碳和营养循环沿着梯度站从河口低营养的货架沃茨，以确定在这个系统中的变化和恢复率和大型飓风输入缺氧，缺氧和海洋酸化的关系。这些数据正被用于开发一个区域模型，以预测未来飓风对海洋酸化、浮游植物大量繁殖以及局部缺氧和缺氧的影响。这项研究利用了州和联邦管理机构资助的持续监测项目，以及NSF支持的本科生项目。它为博士后研究人员和一名研究生的培训提供部分支助。2022年9月，佛罗里达西南部遭受了4级飓风伊恩的直接袭击，导致广泛的流域洪水和富含营养物质和溶解有机物的河口羽流延伸到浅贫营养的西佛罗里达大陆架（WFS）上超过50英里。大规模的陆地有机碳和营养物质输入西南佛罗里达沿海和大陆架地区可能会引发这种贫营养系统广泛的浮游植物水华，以及碳化学和营养循环的显着变化，可能会导致长期的区域缺氧和缺氧。在这个RAPID项目中，研究人员将于2022年12月、2023年2月和2023年9月在夏洛特港和邻近的内部WFS系统的站点测量一系列碳和养分参数，以及碳和养分循环。目标是评估：1）飓风后从较短（数周至数月）到1年影响的系统响应时间尺度; 2）营养物质的可用性和形式如何影响缺氧;以及3）飓风驱动的输入如何影响该系统中的碳酸盐化学，特别是酸化和缺氧之间的联系。研究人员正在使用本研究中收集的新数据以及来自地区州和联邦计划的监测数据，以耦合流体动力学-地球化学模型来了解WFS的条件。事后模拟和建模实验正在评估大量营养物质和有机物质的输入如何影响浮游植物，氧气条件和碳化学。模拟实验正在探索不同风和降水强度的风暴如何影响WFS和河口，确定WFS从偶发性转变为持续缺氧的临界点。该奖项反映了NSF的法定使命，并被认为值得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来支持。

Many coastal systems are facing the threats of continuing development and climate change, including an increased intensity of extreme weather events such as hurricanes. Such storms are now wetter than in prior years because warmer atmospheres hold more moisture. Thus, they release more rainfall and deliver more nutrients and organic matter to coastal areas. This, in turn, leads to phytoplankton blooms with potential for regional “dead zones” or areas with little or no dissolved oxygen. Hurricane Ian, a category 4 hurricane which hit southwest Florida in late September 2022, resulted in immense nutrient and organic carbon inputs to the coastal estuaries and southwest Florida shelf waters and presents an opportunity to examine the effects of a major storm disturbance on a coastal system that is under increasing coastal nutrient stress. The objective of this RAPID project is to examine carbon and nutrient cycling along a gradient of stations from the estuary to low-nutrient shelf waters to determine the rate of change and recovery in this system and the relationship of large hurricane inputs to hypoxia, anoxia, and ocean acidification. These data are being used to develop a regional model to predict the impact of future hurricanes on ocean acidification, phytoplankton blooms, and local hypoxia and anoxia. This study leverages ongoing monitoring programs funded by state and federal management agencies, as well as NSF-supported programs for undergraduate students. It provides partial support for training of postdoctoral investigators and a graduate student. Outreach will include presentations to elementary and high school students.In September 2022, southwest Florida experienced a direct hit from category-4 Hurricane Ian, resulting in extensive watershed flooding and nutrient- and dissolved-organic-matter-laden estuarine plumes extending more than 50 miles onto the shallow oligotrophic west Florida shelf (WFS). The massive terrestrial organic carbon and nutrient inputs to the southwest Florida coastal and shelf region may be priming this oligotrophic system for extensive phytoplankton blooms, as well as significant changes in carbon chemistry and nutrient cycling that could lead to longer-term regional hypoxia and anoxia. In this RAPID project, the investigators are measuring a suite of carbon and nutrient parameters, as well as carbon and nutrient cycling, at stations in Charlotte Harbor and the adjacent inner WFS system in December 2022, February 2023, and September 2023. The objectives are to assess: 1) a timescale of system responses from shorter (weeks to months) to 1-year impacts post-hurricane; 2) how nutrient availability and forms influence hypoxia; and 3) how hurricane-driven inputs influence carbonate chemistry in this system, specifically the connection between acidification and hypoxia. The investigators are using new data collected in this study and monitoring data from regional state and federal programs in a coupled hydrodynamic-biogeochemical model to understand conditions on the WFS. Hindcast simulations and modeling experiments are assessing how large inputs of nutrients and organic matter affect phytoplankton, oxygen conditions, and carbon chemistry. Modeling experiments are exploring how storms of varying wind and precipitation intensity affect the WFS and estuaries, identifying the tipping point at which the WFS switches from episodic to persistent hypoxia.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.