Collaborative Research: Ecosystem Evolution and Sustainability of Nutrient Enriched Coastal Saltmarshes

合作研究：营养丰富的沿海盐沼的生态系统演化和可持续性

• 批准号: 1354494
• 负责人: Linda Deegan
• 金额: $ 114.84万
• 依托单位: Marine Biological Laboratory
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-03-01 至 2017-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1354494&HistoricalAwards=false
• 关键词: Collaborative; Research; Ecosystem; Evolution; Sustainability

Overview: Salt marshes provide a broad suite of critical ecosystem services but also face multiple anthropogenic threats including nutrient enrichment and accelerated sea-level rise. Complex interactions between primary production, decomposition, sedimentation, and sea level rise determine the tipping point relative to the rate of sea-level rise beyond which the marsh may convert to open water. Nitrate - the dominant form of coastal N-enrichment - acts as both a powerful electron acceptor stimulating microbial decomposition and as a fertilizer stimulating plant growth with the potential to transform saltmarshes through interactive feedbacks in key plant and microbial processes, potentially lowering the tipping point relative to sea-level rise. It is urgent that we understand the impacts of coastal enrichment on saltmarshes in part because of their globally rapid loss, and in part because salt marshes have become the focus of large-scale restoration strategies costing millions to billions of dollars to serve as storm buffers for coastal cities and as "blue" carbon pools to mitigate climate change. The TIDE saltmarsh experiment is a unique ecosystem-scale test of how nutrient enrichment affects ecosystem structure, function, and long-term sustainability. Contrary to well-accepted saltmarsh models, TIDE has shown that nutrients can drive saltmarsh loss; however, important questions about causality, and whether geomorphic and ecosystem function will continue to change or reach a new landscape equilibrium with nutrient loading, remain unanswered. Given the ongoing changes observed by the project to date, the PI will continue the experiment for a total of 13 years to address: (1) long-term landscape evolution (autocatalytic or self-limiting?), (2) plant mechanisms (Is environmental filtering selecting for plants with lower belowground biomass that are less flood tolerant?); (3) microbial mechanisms (Does NO3- remove resource limitation on the microbes and disproportionately stimulate creek bank denitrifiers/decomposers?); and (4) the consequences for ecosystem function (With loss of creek edge marsh, do saltmarshes retain less N?). The investigators will use a combination of whole-ecosystem experimental manipulations, genetic approaches, common garden experiments, and enriched 15N-NO3 - additions and delta 15N values in ecosystem components to understand mechanisms underlying ecosystem geomorphic and N cycle changes. This project incorporates new researchers to address questions of geomorphologic change, plant and microbial genetics, gene expression, whole-system ecosystem nutrient cycling, and denitrification.Intellectual Merit: This interdisciplinary project involving ecosystem, plant, microbial, biogeochemical, and geological researchers will test fundamental questions about controls on ecosystem structure and function and the long-term sustainability of nutrient enriched wetlands. Many detritus-based wetland ecosystems worldwide (boreal, tundra, salt- and fresh-water wetlands) are unexpectedly crossing tipping points suggesting there is a need to re-assess our theories and understanding on the nature and pace of their response to perturbation. Developing a predictive understanding of the controls on tipping points in natural ecosystems, and how these tipping points are altered by human activities, represents a major challenge in ecosystem science.Broader Impacts: The broader social impacts of this project lie in addressing a globally important issue, coastal eutrophication. The educational impacts include enhancing high school to graduate student interdisciplinary training through a structured rotation among disciplines and hands-on field research. New partnerships with minority serving institutions and a RUI women's college will engage urban, underprivileged and minority students. A whole-ecosystem experiment is supported as a living lab for education and research infrastructure for the scientific community. The MBL's Science Journalism Program and the Parker River National Wildlife Refuge will be used to showcase the results to the public. Management outreach through workshops co-hosted with EPA and the Waquoit Bay National Estuarine Research Reserve will engage local, state and federal managers.

概述：盐沼提供了一系列关键的生态系统服务，但也面临着多种人为威胁，包括营养富集和加速的海平面上升。初级生产，分解，沉积和海平面上升之间的复杂相互作用决定了临界点相对于海平面上升速率，沼泽可能会转化为开放水。硝酸盐 - 沿海n-富集的主要形式 - 既是刺激微生物分解的强大电子受体，又充当肥料刺激植物生长的肥料，有可能通过关键植物中的交互式反馈和微生物过程中的交互式反馈转化盐晶，从而有可能降低相对于海平面上升的倾斜点。迫切需要了解沿海富集对盐木的影响部分是因为它们在全球范围内迅速损失，部分原因是盐沼泽已成为大规模修复策略的重点，耗资数百万到数十亿美元，以作为沿海城市的风暴缓冲区，以及“蓝色”碳池以减轻气候变化。 Tide Saltmarsh实验是对营养富集如何影响生态系统结构，功能和长期可持续性的独特生态系统规模的测试。与经过良好接受的盐晶模型相反，潮汐表明营养可以驱动盐泥损失。但是，有关因果关系的重要问题，以及在养分负荷的情况下，地貌和生态系统功能是否会继续改变或达到新的景观平衡，但仍未得到解答。鉴于该项目迄今为止观察到的正在进行的变化，PI将继续进行13年的实验，以解决：（1）长期景观演化（自体催化或自限制？），（2）植物机制（环境过滤是为较低的地下生物量较低的耐洪水量较低的植物选择植物吗？）； （3）微生物机制（NO3-是否消除了微生物的资源限制，并不成比例地刺激了Creek Bank Denitrifiers/Demomposers？）； （4）生态系统功能的后果（随着溪流沼泽的损失，盐玛希人保留较少的n吗？）。研究人员将结合整个生态系统实验操作，遗传方法，常见的花园实验以及富集的15N-NO3-生态系统组件中的添加和Delta 15n值，以了解生态系统地质形态和N周期变化的机制。 This project incorporates new researchers to address questions of geomorphologic change, plant and microbial genetics, gene expression, whole-system ecosystem nutrient cycling, and denitrification.Intellectual Merit: This interdisciplinary project involving ecosystem, plant, microbial, biogeochemical, and geological researchers will test fundamental questions about controls on ecosystem structure and function and the long-term sustainability of营养丰富的湿地。全球许多基于碎屑的湿地生态系统（北方，苔原，盐和淡水湿地）意外地越过临界点，表明有必要重新评估我们的理论和对他们对扰动的反应的性质和节奏。对自然生态系统中临界点的控制的控制有预测的理解，以及这些临界点如何因人类活动而改变，这代表了生态系统科学中的主要挑战。BROADER的影响：该项目的更广泛的社会影响在于解决全球重要问题，沿海富营养化。教育影响包括通过学科和动手实地研究之间的结构化轮换来增强高中跨学科培训。与少数派服务机构以及RUI女子学院的新伙伴关系将与城市，弱势群体和少数族裔学生联系。一项全生态系统实验被支持作为科学界的教育和研究基础设施的生活实验室。 MBL的科学新闻计划和帕克河国家野生动物保护区将用于向公众展示结果。通过与EPA和Waquoit湾国家河口研究保护区共同主持的研讨会的管理层宣传将与地方，州和联邦经理互动。