LTREB Renewal: Twenty-three years of tidal marsh response to environmental change

潮汐湿地构成了沿海和河口生态系统的生态结构，提供生态系统服务，如滋养食物链，过滤水和保护沿海人口。 气候预测一致认为，下个世纪全球海平面将上升，威胁到这些重要的栖息地。目前，每年有数千公顷的低洼沿海湿地流失到浅水、开阔水域，威胁着渔业、野生动物栖息地、水质和基础设施。该项目将研究大气二氧化碳浓度升高、氮污染、气候变化、海平面上升和植物入侵如何相互作用，影响潮汐沼泽生态系统的可持续性。在研究地点进行的大量长期全球变化研究为这些因素的相对重要性提供了前所未有的比较。该研究项目将吸引公民志愿者，高中生，本科实习生和研究生，为教育和培训广泛的社会需求主题做出贡献。从拟议的研究中获得的信息将为旨在保护和恢复沿海湿地的管理实践提供信息。碳增加和碳损失的平衡最终决定了潮汐湿地以与海平面上升相匹配的速度增加海拔的能力，从而在快速变化的环境中持续存在。 该项目将测试关于大气二氧化碳、海平面、氮污染和气候变化对沿海沼泽生态系统中植物碳同化和微生物碳矿化的影响的假设。该项目23年的数据表明，从长期趋势来看，短期内看来重要的影响可能会被消除或逆转。研究人员将使用操纵二氧化碳和氮的补充实验来评估植物性状对生态系统响应的影响，其基础是植物群落组成的变化将介导全球变化对生态系统可持续性的最重要影响。结果将有助于一个新的模型，确定相对海平面的全球变化因素，取代所有其他的，其次是氮的补充，最后升高的CO2。这些全球变化因素的排名是基于它们在自然变异范围内重组植物群落组成的能力。

Tidal wetlands make up the ecological fabric of coastal and estuarine ecosystems providing ecosystem services such as nourishing food chains, filtering water, and protecting coastal populations. Climate predictions agree that sea level will rise globally over the next century, threatening these critical habitats. The current loss of thousands of hectares of low-lying coastal wetlands to shallow, open water each year threatens fisheries, wildlife habitat, water quality, and infrastructure. This project will examine how elevated atmospheric carbon dioxide, nitrogen pollution, climate change, sea-level rise and plant invasion interact to influence the sustainability of tidal marsh ecosystems. The wealth of long-term global change research at the study site affords an unprecedented comparison of the relative importance of these factors. The research project will engage citizen volunteers, high school students, undergraduate interns, and graduate students, contributing to education and training of a broad group in a subject of pressing societal need. The information garnered from the proposed research will inform management practices aimed at protecting and restoring coastal wetlands.The balance of carbon gain and carbon loss ultimately determines the capacity of a tidal wetland to increase elevation at a rate that matches sea-level rise, and thus persist in a rapidly changing environment. This project will test hypotheses about the consequences of changes in atmospheric carbon dioxide, sea level, nitrogen pollution, and climate for carbon assimilation by plants and carbon mineralization by microbes in a coastal marsh ecosystem. Twenty-three years of data from this project show that effects that appear important in the short term may be obviated or reversed when longer-term trends are considered. The researchers will use complementary experiments that manipulate carbon dioxide and nitrogen to assess the effects of plant traits on ecosystem responses, based on the central hypothesis that changes in plant community composition will mediate the most important effects of global change on ecosystem sustainability. Results will contribute to a new model that identifies relative sea level as the global change factor that supersedes all others, followed by N addition, and finally elevated CO2. The ranking of these global change factors is based on their capacity to restructure plant community composition within the bounds of natural variability.