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（Tidal marsh wetland）能够为人类社会以及更广范围的互联海洋与近岸环境提供不可或缺且极具价值的服务。明晰其相互交织的生物物理过程与地貌演化规律，对于制定行之有效的湿地保护与管理策略以应对全球变化至关重要。本研究区位于中国江苏省斗龙地区的开敞潮滩，属于冲淤过渡型湿地。本研究构建了2020年9月至2021年7月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内容。观测结果表明，同步获取的物理与生物数据可更全面、精准地解析地貌单元的演化过程，反映潮盐沼（Tidal salt marsh）系统内多因子的相互作用机制。本次观测发现两类典型地貌格局：一是盐沼斑块的沿岸扩张，二是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特征（一年内扩张达180米），随后发生斑块间连通并与周边盐沼湿地拼接融合。在该岸线凸出型盐沼的背景下，强劲的沿岸流是实现沿岸扩张的必要条件。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。夏季期间，碎屑带可导致植被生物量降低约52%，其余季节则降低约30%。根据运动特征与组成成分，碎屑带可分为稳定型、移动型与有机型三大类；无植被区则依据其存续时长分为持久型与临时型两类。