Collaborative Proposal: Coupled C, N and S cycling in coastal plain wetlands: how will climate change and salt water intrusion alter ecosystem dynamics?

滨海平原湿地在陆地和水生、淡水和咸水沃茨的交汇处占据着重要的景观位置。与所有湿地一样，沿海湿地在提供的服务方面与它们所包含的区域相比具有不成比例的价值，包括营养转化，水净化和洪水控制。 人类已经抽干了东南沿海平原大部分地区的湿地用于农业和林业，从而降低了它们提供关键生态系统服务的能力，如养分和碳固存。 与此同时，集约化肉类和家禽生产所产生的肥料和粪便大大增加了沿海生态系统的营养负荷。 营养物的负荷增加和保留减少造成下游淡水和沿海生态系统的富营养化，造成水质退化和沿海渔业减少。 气候变化可能会进一步加剧这些趋势：气温升高和越来越零星的降水可能会进一步缩小常年泛滥的湿地的空间范围，并已导致干旱期间的季节性盐水入侵。 预测可能的生态系统的碳和养分循环的沿海平原淡水到一个咸和越来越不确定的水文未来需要显着改善我们目前的淡水生态系统的理解。 该提案战略性地集中在这个问题的两个方面：第一，将硫（~海盐）动态纳入我们对微生物如何改变碳和营养循环的理解，第二，利用模拟建模将动态水文学与微生物生物地球化学结合起来。 适应性模拟建模与有针对性的实证工作将使我们能够快速测试和完善当前的湿地碳和养分循环模型，并将新兴的湿地生态地球化学概念理解形式化为一个灵活的，易于调整的建模框架。 焦点现场是北卡罗来纳州沿海平原的一个以前被挖沟和排水的农田，2007年恢复为河流湿地水文，成为东南部最大的私人拥有的缓解银行。该场地的地形起伏很小（-1至+1 m高程）;夏季干旱期间，通过地表水混合，盐水侵入显著;并且具有由风潮汐驱动的水文，在时间和空间上产生硫浓度的大梯度。 该场地是东南沿海平原农业景观大面积的代表，正在积极恢复或放弃。 该项目的经济和生态“成功”将受到整个地区的监管机构和从业人员的密切关注。 这项研究计划将直接影响场地所有者在新兴生态系统服务市场出售经验证的碳和营养物信用额的潜力。 由此产生的研究结果（连同其经济影响）将影响整个东南沿海平原未来的减缓和保护投资模式，并将提供关键信息，促进整个地区的气候适应规划。

Coastal plain wetlands occupy a critical landscape position at the intersection of terrestrial and aquatic and fresh and salt waters. Like all wetlands, coastal wetlands are disproportionately valuable in terms of services provided compared to the area they comprise including nutrient transformation, water purification, and flood control. Humans have drained wetlands throughout much of the southeastern coastal plain for agriculture and forestry, thus diminishing their capacity to provide critical ecosystem services such as nutrient and carbon sequestration. At the same time, fertilizer use and manure from intensive meat and poultry production have dramatically increased nutrient loading to coastal ecosystems. Increased loading and decreased retention of nutrients has caused eutrophication of downstream freshwater and coastal ecosystems, with the associated degradation in water quality and decline in coastal fisheries. Climate change may further exacerbate these trends: higher temperatures and increasingly sporadic precipitation may further diminish the spatial extent of perennially flooded wetlands and is already leading to seasonal salt water intrusion during drought. Predicting the likely ecosystem carbon and nutrient cycling of coastal plain freshwaters into a saltier and increasingly uncertain hydrologic future requires significant improvements to our current understanding of freshwater ecosystems. This proposal focuses strategically on two aspects of this problem: first, incorporating sulfur (~from sea salt) dynamics into our understanding of how microbes alter carbon and nutrient cycling and second, utilizing simulation modeling to mesh dynamic hydrology together with microbial biogeochemistry. Adaptive simulation modeling together with targeted empirical work will allow us to rapidly test and refine current models of wetland carbon and nutrient cycling and to formalize the emerging conceptual understanding of wetland biogeochemistry into a flexible, easily adjusted modeling framework. The focal field site is a formerly ditched and drained agricultural field in North Carolina's coastal plain that was restored to riverine wetland hydrology in 2007, becoming the largest privately owned mitigation bank in the southeast. The site has very little topographic relief (-1 to +1 m elevation); experiences significant salt water intrusion via surface water mixing during summer droughts; and has wind tide driven hydrology that generates large gradients in sulfur concentrations in both time and space. The field site is representative of large areas of SE coastal plain agricultural landscapes that are being actively restored or abandoned. The economic and ecological "success" of this project will be closely watched by regulators and practitioners throughout the region. This research program will directly affect the potential for site owners to sell validated carbon and nutrient credits in emerging ecosystem service markets. Resulting research findings (together with their economic implications) will influence future patterns of mitigation and conservation investment throughout the southeastern coastal plain and will provide critical information that will facilitate climate adaptation planning throughout the region.