Collaborative Research: The interplay of nitrogen loading and ecosystem sustainability in threatened wetlands: an extension of the WETFEET project

在过去的十年里，佛罗里达河口的污染已经造成了可怕的后果，如赤潮和鱼类和海洋哺乳动物的大规模死亡。这个研究小组与佛罗里达东北部的土地管理人员密切合作，他们寻求数据驱动的指导，以减轻污染并帮助维持这些湿地。由于海平面上升，重要的湿地生境越来越多地被边缘的侵蚀和内陆的“积水”所淹没。随着海平面的上升和污染的加剧，保护佛罗里达人口免受大风暴袭击的薄绿色植被带正在从盐沼草地变成红树林。为了确定这些湿地在未来更高的海平面，更多的营养物质投入和更大的植物中将如何发展，该项目将结合实地实验，绘图和数学建模。将获得关于沿海湿地如何帮助去除氮的信息，氮是沿海沃茨的一种常见污染物。研究人员将调查湿地的减少是否导致了目前营养水平的上升，从而威胁到人类和其他动物的健康。最后，该团队将利用他们与佛罗里达东北部土地管理者、政府官员和恢复工作者建立的关系，帮助规划Guana Tolomato马坦萨斯国家河口研究保护区（GTMNERR）及其他地区这些受威胁湿地的未来。该项目的数据将用于绘制GTMNERR中的营养热点，并培训沿海湿地研究的本科生和研究生研究人员，并制定恢复计划。在佛罗里达东北部，沿海湿地生态系统面临着海平面上升和污染负荷，并正在经历由气候驱动的植被从沼泽植物到红树林的巨大转变。氮（N）富营养化和海平面上升都可能严重影响沿海湿地。本项目将探讨这两个问题如何通过沿海湿地反馈联系起来，这是本项目三个核心假设的基础：（1）过量的氮负荷可能会中断维持湿地的土壤积累机制;（2）沼泽转化为红树林大大增加了对氮的需求，这可能会减轻邻近水道的氮污染;（3）N-富营养化可以满足红树林对N的需求，从而加速沼泽向红树林的转化。过去的研究表明，氮添加可以通过刺激有机物的损失来阻碍湿地跟上海平面上升的能力，而其他研究表明，氮添加可以促进植物生长，这可以帮助维持沿海湿地。这种差异可能是由于湿地边缘和内部的地貌过程存在明显的差异。该项目将直接解决这一差异，利用现有的基础设施进行实验N除了在溪边和内部位置，除了比较沼泽和相邻的红树林为主的地块的第一次N的影响。将测试新的假设，N可能会改变海拔上升和红树林侵蚀整个景观的机制，以及如何持续的湿地损失和沼泽红树林的转换可能会对沿海N预算产生巨大影响的假设。在最近的一次沿海脆弱性研讨会（2021年9月）上，GTMNERR管理层将研究氮对湿地对海平面上升的恢复力的影响确定为研究重点。该研究团队将利用GTMNERR水质数据和我们自己从该项目中收集的数据，在沿海脆弱性地图上建立一个新的营养层，这将有助于优先考虑GTMNERR网站的保护和恢复计划。 研究结果将通过与GTMNERR的环境教育中心合作向公众传达，为游客和营地制作展览和课程。此外，还将在维拉诺瓦大学、中央佛罗里达大学和罗斯福大学这三个机构对年轻科学家进行跨学科培训。该奖项反映了NSF的法定使命，并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，被认为值得支持。

Over the last decade, pollution in Florida estuaries has had dire consequences such as red tides and massive die-offs of fish and marine mammals. This team of researchers has worked closely with land managers in northeastern Florida who seek data-driven guidance on strategies to mitigate pollution and help sustain these wetlands. Critical wetland habitats are increasingly being lost to erosion at the edges, and "ponding" in the interior due to sea level rise. As sea levels and pollution are increasing, the thin green strips of vegetation that protect Florida’s human population from big storms are changing from salt marsh grasses to mangrove forests. To determine how these wetlands will fare in a future with higher seas, more nutrient inputs, and larger plants, this project will use a combination of field experiments, mapping, and mathematical modeling. Information will be obtained on how coastal wetlands can help remove nitrogen, a common pollutant in coastal waters. The researchers will investigate whether wetland decline is contributing to the current uptick in nutrient levels that threatens the health of humans and other animals. Finally, the team will use the relationships that they have built with northeastern Florida land managers, government officials and restoration practitioners to help plan for the future of these threatened wetlands in the Guana Tolomato Matanzas National Estuarine Research Reserve (GTMNERR) and beyond. Data from this project will be used to map nutrient hotspots in the GTMNERR, and to train undergraduate and graduate student researchers in the study of coastal wetlands and plan for their restoration. In northeastern Florida, coastal wetland ecosystems are faced with rising seas and pollution loads, and are undergoing dramatic climate-driven vegetation conversion from marsh plants to mangroves. Nitrogen (N) eutrophication and rising sea levels each individually can severely impact coastal wetlands. This project will explore how these two problems may be linked by coastal wetland feedbacks, which underlie the project's three central hypotheses: (1) Excess N loading may interrupt the mechanisms of soil accumulation that sustain wetlands; (2) Conversion of marsh to mangrove greatly enhances N demand which may mitigate N pollution of adjacent waterways; (3) N-eutrophication can accelerate transformation of marsh to mangrove by satisfying the greater N demand of mangroves compared to marsh plants. Past studies have shown that N addition can hinder the ability of wetlands to keep up with sea level rise by stimulating loss of organic matter, whereas others have shown that N addition may promote plant growth, which can help sustain coastal wetlands. The discrepancy may result from stark differences in biogeomorphic processes between wetland edges and interiors. This project will address this discrepancy directly by leveraging established infrastructure to conduct experimental N addition at both creekside and interior locations, in addition to comparing N effects on marshes and adjacent mangrove-dominated plots for the first time. New hypotheses will be tested about how N may alter mechanisms of elevation gain and mangrove encroachment across the landscape as well as hypotheses about how ongoing loss of wetlands and conversion of marshes to mangroves could have dramatic effects on coastal N budgets. Examining N influences on wetland resilience to sea level rise was identified as a research priority by the GTMNERR management at a recent coastal vulnerability workshop (September 2021). This team of researchers will work with the GTMNERR water quality data and our own data collection from this project to build a new nutrient layer onto a coastal vulnerability map that will help prioritize GTMNERR sites for planned conservation and restoration initiatives. Research findings will be conveyed to the public by working with the environmental education center at the GTMNERR to produce an exhibit and curricula for visitors and camps. Interdisciplinary training of young scientists will also take place at three institutions- Villanova University, University of Central Florida and Roosevelt University.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.