High resolution bed level change and synchronized biophysical data from 10 tidal flats in northwestern Europe

Tidal flats provide valuable ecosystem services such as flood protection and carbon sequestration. Erosion and accretion processes govern the eco-geomorphic evolution of intertidal ecosystems (marshes and bare flats), and hence substantially affect their valuable ecosystem services. To understand the intertidal ecosystem development, high-frequency bed-level change data are thus needed. However, such datasets are scarce due to the lack of suitable methods that do not involve excessive labour and/or instrument cost. By applying newly-developed Surface Elevation Dynamics sensors (SED-sensors), we obtained unique high-resolution daily bed-level change data sets in the period 2013-2017 from 10 saltmarsh sites situated in the Netherlands, Belgium and Britain in contrasting physical and biological settings. At each site, multiple sensors were deployed for 9-20 months to ensure sufficient spatial and temporal coverage of highly variable bed level change processes. The bed level change data are provided with synchronized hydrodynamic data, i.e. water level, wave height, tidal current velocity, and medium grain size (D50) as well as (for some sites) chlorophyll-a level and organic matter content of the surface sediment. This dataset has revealed diverse spatial morphodynamic patterns over daily to seasonal scales, which are valuable to theoretical and model development. On the daily scale, this dataset is particularly instructive as it includes a number of storm events, the response to which can be detected in the bed level change observations. Such data are rare but useful to study tidal flat response to highly energetic conditions.

潮滩（tidal flats）提供诸多极具价值的生态系统服务，例如防洪与固碳。侵蚀与淤积过程主导着潮间带生态系统（盐沼与光滩）的生态地貌演化，进而显著影响其宝贵的生态系统服务功能。为明晰潮间带生态系统的发育规律，亟需获取高频的床面高程变化数据。然而，此类数据集较为匮乏，原因在于缺乏兼具低人力投入与低仪器成本的合适观测方法。通过采用新研发的地表高程动态传感器（Surface Elevation Dynamics sensors，简称SED-sensors），我们获取了2013-2017年间，分布于荷兰、比利时与英国的10个盐沼观测点的独特高分辨率逐日床面高程变化数据集，这些观测点涵盖了迥异的物理与生物环境背景。每个观测点均部署了多台传感器，观测时长为9至20个月，以确保对高度动态变化的床面高程变化过程实现充分的时空覆盖。该数据集配套提供了同步观测的水动力数据，包括水位、波高、潮流流速以及表层沉积物中值粒径（D50）；部分观测点还额外提供了叶绿素a（chlorophyll-a）浓度与表层沉积物有机质含量数据。本数据集揭示了逐日至季节尺度下多样的空间地貌动力模式，对相关理论研究与模型开发具有重要价值。在逐日尺度上，该数据集尤为珍贵，因其涵盖了多场风暴事件，通过床面高程变化观测可捕捉到生态系统对风暴的响应过程。此类数据十分稀缺，但对于研究潮滩在高能动力条件下的响应机制具有重要意义。