Keeping above the waves? The response of coastal freshwater peatlands to sea-level rise.

人们对沿海咸水生态系统如何适应海平面上升以及它们是否会迅速上升以保持其在潮汐棱镜中的相对位置非常感兴趣。引起这种兴趣是因为盐沼和红树林作为天然海岸防御和作为区域和全球重要的（蓝色）碳储存库的重要性。沿海淡水湿地，特别是泥炭地，如洪泛区沼泽，受到的关注少得多。气候变化引起的海平面上升是这些沿海淡水湿地的潜在主要威胁。咸水或更高的地下水的进入会破坏其现有的植物群落和碳汇功能。此外，目前受这些湿地保护的内陆地区可能更容易发生洪水。有一些证据表明，这些湿地在过去因海平面上升而增加了泥炭堆积的速度。然而，人们对其中的机制知之甚少，如果不了解这些机制，我们就无法预测它们对未来海平面快速上升的可能反应。了解淡水湿地对海平面上升的反应是政策制定者和土地管理者在适应变暖世界时的首要任务。这项工作具有国际意义，因为世界上有大量处于危险中的低洼湿地。这将有助于指出在哪里优先进行管理工作，也可能表明随着海岸线向内陆移动，哪里可能形成新的泥炭地。为了解决这一关键的研究缺口，该项目将采用过去-现在-未来的方法，结合古生态学、过程基础和建模工作来了解沿海淡水泥炭地对海平面上升的反应。这项研究将集中在两个截然不同的英国地点：Cors Fochno（威尔士中部的河口营养型沼泽）和Wheatfen（诺福克的洪泛平原沼泽）。具体来说，该项目将包括：i)分析从两个地点采集的泥炭岩心，以了解它们对过去海平面上升时期的反应；Ii)收集数据，了解当前过程和碳积累速率如何适应水文和盐度变化；iii)利用气象局在淡水泥炭地地区的海平面预测和DigiBog泥炭地模型来模拟泥炭地对气候和海平面变化的过去和未来的反应。项目组成员将Wheatfen建成了一个“生态水文观测站”，并提供了最近收集的关于沼泽地水位和盐水暴涨的数据集。

Project Background There is considerable interest in how coastal saltwater ecosystems might adjust to sea-level rise and whether they will accrete rapidly enough to maintain their relative position in the tidal prism. This interest has arisen because of the importance of salt marshes and mangroves as natural coastal defences and as regionally- and globally-important (blue) carbon stores. Significantly less attention has been given to coastal freshwater wetlands, in particular peatlands such as floodplain fens. Sea-level rise caused by climate change is a potential major threat to these coastal freshwater wetlands. The ingress of saline water or higher groundwater could destroy their existing plant communities and their carbon sink function. In addition, inland areas currently protected by these wetlands may become more prone to flooding. There is some evidence that such wetlands have in the past increased their rates of peat accumulation in response to rising sea levels. However, the mechanisms involved are poorly understood, and without that understanding we cannot predict their likely response to future, rapid, increases in sea level. Understanding freshwater wetland response to sea level rise is a priority for policymakers and land managers as they adapt for a warmer world. The work has international relevance, with a large number of at-risk low-lying wetlands around the world. It will help indicate where to prioritise management efforts and may also show where new peatlands might form as shorelines move inland.Project Aims and Methods To address this critical research gap, this project will use a past-present-future approach, combining palaeoecological, process-based, and modelling work to understand the response of coastal freshwater peatlands to sea-level rise. The study will focus on two contrasting UK sites: Cors Fochno (an estuarine ombrotrophic bog in mid-Wales) and Wheatfen (a floodplain fen in Norfolk). Specifically, the project will involve: i) analysis of peat cores taken from both sites to understand their response to periods of past sea-level rise; ii) data collection to understand how current process and carbon accumulation rates adjust to hydrological and salinity changes; iii) modelling work using Met Office sea level projections in areas of freshwater peatlands, and the DigiBog peatland model to simulate past and future responses of the peatlands to changes in both climate and sea level. Wheatfen has been set up as an 'ecohydrological observatory' by members of the project team, and recently-collected datasets on fen water levels and saline surges are available.