Synchronized biophysical measurements of an accretional-erosional transitional tidal marsh wetland in the central Jiangsu Coast, China

Tidal marsh wetlands provide essential and valuable services to human society and the wider interconnected marine and coastal environment. Understanding their intertwined biophysical processes and morphological evolution is crucial for developing effective management strategies to conserve and protect wetlands in the face of global change. The study area is an accretional-erosional transitional wetland on an open tidal coast, which is located in Doulong, Jiangsu Province, China. This study presents a dataset of seasonal synchronized biophysical measurements from September 2020 to July 2021, including morphological patterns, bed elevation, hydrodynamics, vegetation, and sediment characteristics. Observations show that synchronous physical and biological data can result in a more comprehensive and accurate understanding of the evolution of geomorphological units, reflecting the multi-factor interactions in tidal salt marsh systems. Two specific morphological patterns were observed: the alongshore expansion of saltmarsh patches, and the evolution of debris bands and unvegetated zones within saltmarshes. In the northern part of the study area, the seaward expansion of saltmarshes was characterized by rapid alongshore expansion (180 m in one year), followed by the connection of patches and merging with the marshland. In the context of this protruded-shoreline marsh, the strong alongshore currents were the essential conditions for the alongshore expansion. Moreover, results showed that debris bands and unvegetated zones have a significant impact on the evolution of salt marshes. Debris bands could result in a reduction of approximately 52% in vegetation biomass during summer and approximately 30% during other seasons. They were classified into three main categories according to their movement and composition: stable, movable and organic type. Unvegetated zones were classified into two categories based on their duration: persistent and transient type.

潮滩湿地可为人类社会以及更广范围的互联海洋与海岸环境提供不可或缺且极具价值的生态服务。明晰其相互交织的生物物理过程与地貌演化机制，对于制定应对全球变化的湿地保护与高效管理策略至关重要。本研究的研究区位于中国江苏省斗龙地区，属于开敞型潮间带海岸上的冲淤转换型过渡湿地。本研究构建了2020年9月至2021年7月间的季节性同步生物物理观测数据集，涵盖地貌格局、床面高程、水动力条件、植被特征与沉积物特性等核心指标。观测结果表明，同步获取的物理与生物观测数据可更为全面准确地解析地貌单元的演化过程，直观反映潮盐沼系统内的多因子交互作用机制。本次观测识别出两类典型地貌演化格局：其一为盐沼斑块的沿岸扩张过程，其二为盐沼内部碎屑带与无植被区的演化过程。在研究区北部，盐沼的向海扩张以快速沿岸扩张为典型特征（一年内沿岸扩张达180米），随后各斑块相互连接并与周边沼地融为一体。在该岸线突出型盐沼的背景下，强劲的沿岸流是驱动沿岸扩张的核心条件。此外，研究结果显示碎屑带与无植被区对盐沼演化具有显著影响：夏季时碎屑带可导致植被生物量减少约52%，其余季节减少约30%。依据运动特征与物质组成，碎屑带可划分为稳定型、移动型与有机型三大类别；无植被区则依据存在时长划分为持久性与暂时性两类。