Suspended sediment transport and deposition are crucial physical processes controlling the geomorphological evolution of estuaries and bays. Specially, under the context of worldwide coastal erosion, knowledge of the spatio-temporal distribution of suspended sediment concentration (SSC) and its associated sediment load have become increasingly important for bay management. However, our understanding of the mechanisms of suspended sediment dynamics continues to be hampered by the lack of high-resolution observations. Here, we present a study of the transport mechanisms and controlling factors of suspended sediment over Laizhou Bay. For this, we conducted continuous measurements of SSC, salinity, temperature, and flow velocity at nine stations throughout Laizhou Bay for one 25-h period during each of the spring and moderate tides. Based on these data, residual current, gradient Richardson numbers, and suspended sediment flux were calculated. Our results indicate that a strong current field occurs near the Yellow River mouth, corresponding to the zone with high SSC. The overall diffusion characteristics of suspended sediment are controlled by the tidal current field. Furthermore, our findings suggest that different degrees of stratification occur in the water column, which inhibit the effective vertical diffusion of suspended sediment; Higher water temperature was the main cause of stronger water column stratification of spring tide than moderate tide. Finally, our results reveal that the type of seabed sediment is an important factor controlling SSC by influencing resuspension flux. We conclude that the primary mechanisms controlling suspended sediment transport in Laizhou Bay are advection and tidal pumping, especially advection. Our research provides both a foundational reference for the sediment source-to-sink process from the Yellow River to the sea, as well as guideline implications for coastal engineering construction and channel dredging.

悬浮泥沙输送和沉积是控制河口和海湾地貌演化的关键物理过程。特别是在全球海岸侵蚀的背景下，了解悬浮泥沙浓度（SSC）的时空分布及其相关的泥沙负荷对于海湾管理变得越来越重要。然而，由于缺乏高分辨率观测，我们对悬浮沉积物动力学机制的理解继续受到阻碍。在这里，我们对莱州湾悬浮泥沙的输送机制和控制因素进行了研究。为此，我们在春潮和中潮期间，在整个莱州湾的 9 个站点连续测量了 25 小时的 SSC、盐度、温度和流速。基于这些数据，计算剩余电流、梯度理查森数和悬浮泥沙通量。我们的研究结果表明，黄河口附近出现强电流场，对应于高SSC区域。悬浮泥沙的整体扩散特性受潮流场控制。此外，我们的研究结果表明，水体中存在不同程度的分层，这抑制了悬浮沉积物的有效垂直扩散；较高的水温是大潮水柱分层强于中潮的主要原因。最后，我们的研究结果表明，海底沉积物的类型是通过影响再悬浮通量来控制 SSC 的重要因素。我们得出结论，控制莱州湾悬沙输移的主要机制是平流和潮汐抽吸，特别是平流。我们的研究为黄河入海沉积物源汇过程提供了基础性参考，也为海岸工程建设和航道疏浚提供了指导意义。