近日，意大利帕多瓦大学Davide Tognin团队最新的研究成果显示，沼泽地形揭示了风暴潮驱动的沉积特征。2024年10月23日，国际知名学术期刊《地质学》发表了这一成果。

据悉，盐沼是宝贵的潮汐地貌，由于海平面上升而面临被淹没的威胁。在洪水反复期间，沉积物沉降支持的沼泽吸积可能抵消相对海拔的损失。虽然潮汐洪水通常被描述为向沼泽输送沉积物的主要机制，但风暴潮和海浪可能会深刻影响潮汐流动条件，和浅层潮汐系统中的沉积物再加工，从而引发了这些过程对盐沼积聚相对贡献的一些问题。

该团队人员通过分析威尼斯泻湖（意大利）长达3年的沼泽沉积测量记录，表明风暴潮实质上维持了沼泽沉积物收支，局部贡献了高达90%的沉积物，并对沉积模式产生了严重影响。汹涌增加的水位促进了风浪驱动的沉积物通量直接穿过潮滩-沼泽过渡，改变了潮汐沉积模式，从而影响了沼泽的地形海拔和形态。

通过比较沉积模式和地形剖面，研究人员发现，在沼泽地形中可以找到风暴潮沉积的特征，因此研究人员建议将其作为驱动沼泽垂直演变的易于检测的指标，代表的是不同物理过程的相对贡献。与全球其他具有不同潮差和波浪暴露特征的沼泽进行比较，研究结果支持了盐沼地形剖面与控制沼泽演变的物理过程之间的联系。

附：英文原文

Title: Marsh topography reveals the signature of storm-surge-driven sedimentation

Author: Davide Tognin, Andrea D’Alpaos, Massimiliano Ghinassi, Luca Carniello

Issue&Volume: 2024-10-23

Abstract: Salt marshes are valuable tidal landforms threatened by drowning due to increasing sea levels. Marsh accretion supported by sediment settling during repeated flooding potentially offsets the relative elevation loss. Although tidal flooding is commonly depicted as the main mechanism delivering the sediment to marshes, storm surges and waves may deeply affect tidal flow conditions and sediment reworking in shallow tidal systems, thus raising questions on the relative contribution of these processes to salt-marsh accretion. Here we show that storm surges substantially sustain the marsh sediment budget, locally contributing up to 90% of sedimentation, and critically influence depositional patterns by analyzing a 3-yr-long measurement record of sedimentation on the marshes in the Venice Lagoon (Italy). Surge-enhanced water levels promote wind-wave-driven sediment fluxes directly across the tidal flat-marsh transition, altering tidal sedimentation patterns and, thus, affecting marsh topographic elevation and morphology. By comparing sedimentation patterns and topographic profiles, we show that the signature of storm-surge sedimentation can be found in marsh topography, which we suggest therefore as an easily detectable indicator of the relative contribution of the different physical processes driving marsh vertical evolution. The comparison with other marshes worldwide, characterized by different tidal ranges and wave exposure, consistently supports the link between the salt-marsh topographic profile and the physical processes controlling marsh evolution.

DOI: 10.1130/G52552.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G52552.1/649484/Marsh-topography-reveals-the-signature-of-storm