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，因为温暖的大气中含有更多的水分。因此，它们释放了更多的降雨，并向沿海地区输送了更多的养分和有机物。这反过来又会导致浮游植物大量繁殖，有可能形成地区性的“死亡区”或溶解氧很少或没有的区域。飓风伊恩是2022年9月下旬袭击佛罗里达州西南部的4级飓风，给沿海河口和佛罗里达西南部陆架水域带来了巨大的营养物质和有机碳输入，并提供了一个机会来研究大风暴干扰对处于日益严重的沿海营养物质压力下的沿海系统的影响。这一快速项目的目标是研究从河口到低营养陆架水域的站点梯度上的碳和养分循环，以确定该系统的变化和恢复速度，以及大型飓风输入与缺氧、缺氧和海洋酸化的关系。这些数据正被用来开发一个区域模型，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。这项研究利用了由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研究生的培训提供部分支持。2022年9月，佛罗里达州西南部遭遇了4级飓风伊恩的直接袭击，导致大范围的分水岭洪水和富含营养物质和溶解有机物质的河口羽流延伸到佛罗里达西部浅层少营养陆架(WFS)上50多英里。大量陆地有机碳和营养物质输入到佛罗里达西南部海岸和陆架地区，可能正在为这种低营养系统启动广泛的浮游植物水华，以及碳化学和营养循环的重大变化，这可能导致更长期的区域缺氧和缺氧。在这个快速项目中，研究人员正在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营养参数，以及碳和营养循环。目标是评估：1)从较短时间(几周到几个月)到飓风后一年影响的系统反应的时间尺度；2)养分的可获得性和形式如何影响低氧；以及3)飓风驱动的投入如何影响该系统中的碳酸盐化学，特别是酸化和低氧之间的联系。调查人员正在使用在这项研究中收集的新数据，以及来自地区、州和联邦项目的监测数据，在一个耦合的水动力学-生物地球化学模型中，以了解WFS的条件。后播模拟和模拟实验正在评估营养物质和有机物的大量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力和降水强度的风暴如何影响WFS和河口，确定WFS从间歇性低氧切换到持续性低氧的转折点。这一裁决反映了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。

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.