LTREB: Marsh elevation change in control and fertilized plots in a Spartina alterniflora-dominated salt marsh, North Inlet, Georgetown, SC: 1990-2021

Marsh elevation was measured with a Surface Elevation Table (SET) as a component of a long-term project seeking to understand how salt marsh primary production and sediment chemistry respond to anthropogenic (e.g. eutrophication) and natural (e.g. sea-level rise) environmental change. Feedbacks between plants, sediments, nutrients and flooding were investigated with particular attention to mechanisms that keep marshes in equilibrium with sea level. Other data collected as part of the project include aboveground annual primary productivity, plant biomass, plant density and porewater nutrient concentrations. These data have been used to develop the Marsh Equilibrium Model, an important tool for coastal resource managers. Sampling occurred at 7 Spartina alterniflora-dominated salt marsh sites in North Inlet, a relatively pristine estuary near Georgetown, SC on the SE coast of the United States. North Inlet is a tidally-dominated, bar-built estuary, with a semi-diurnal mixed tide and a tidal range of 1.4m. The 25-km2 estuary is comprised of about 20.5 km2 of intertidal salt marsh and mudflats, and 4.5 km2 of open water. Marsh elevation sampling began in 1990, 1991, 1996 or 2000, depending on the site. Sampling occurred approximately monthly or approximately annually through 2021. The study is on-going. Additionally, some plots were fertilized with nitrogen and phosphorus.本数据集作为一项长期研究项目的组成部分，采用表面高程仪（Surface Elevation Table，SET）测定沼泽高程，旨在阐明盐沼初级生产力与沉积物化学如何响应人为（如富营养化）及自然（如海平面上升）环境变化。研究同时探讨了植物、沉积物、营养盐与潮汐浸淹之间的反馈关系，重点关注维持沼泽与海平面动态平衡的内在机制。本项目还采集了其他相关数据，包括地上部分年初级生产力、植物生物量、植物密度以及孔隙水营养盐浓度。上述数据已被用于构建沼泽平衡模型（Marsh Equilibrium Model），该模型是海岸资源管理者的重要辅助工具。采样工作在美国东南海岸南卡罗来纳州乔治敦附近一处相对原始的河口——北湾（North Inlet）内的7个以互花米草（Spartina alterniflora）为优势种的盐沼样点开展。北湾属于以潮汐作用为主的沙坝型河口，具有半日混合潮型，潮差为1.4米。这片总面积25平方千米的河口区域包含约20.5平方千米的潮间带盐沼与潮滩，以及4.5平方千米的开阔水域。根据样点的不同，沼泽高程采样工作分别于1990年、1991年、1996年或2000年启动。截至2021年，采样工作以每月一次或每年一次的频率持续开展。本研究目前仍在进行中。此外，部分样地施加了氮、磷肥料。