发生在低潮时的降雨及径流能够在潮间带表层与潮沟间造成大量的物质迁移，从而使其成为生地化活动的热点区域。然而在生产力高、物质交换频繁的红树林湿地，相关研究报道极少。申请者提议以深圳福田红树林湿地为对象，研究低潮时降雨对颗粒有机物的迁移及生态环境的影响及其机制。将利用现场观测，定量计算出低潮位降雨影响下的湿地表层和潮沟间的颗粒有机碳交换通量，分析降雨过程中悬浮颗粒有机碳生地化特征的变化机制，并探讨浮游植物群落与其的相互作用。申请者预期可以证明，尽管降雨仅仅是偶发的短效事件，但其通过对表层沉积物的扰动与输运，能够向潮沟输送大量物质，从而在红树林湿地碳循环中扮演了重要角色。更重要的是，未来中国南方将有更多极端降雨事件的发生，因此降雨对潮间带物质生地化循环的影响可能会进一步增强。对这一过程进行更深入的研究有助于防止其负面效应，并加深对潮间带区域生地化过程及机制的认识和理解。

Understanding the processes that control the cycling and characteristics of intertidal zone sediment is essential to evaluating the sustainability of intertidal ecosystems. However, low-tide rainfall-runoff processes, a potential “hot moment” to intertidal zone sediment exchange and cycling, has been overlooked and was poorly quantified, especially in mangrove wetland. I propose to study the effects of rainfall-runoff processes on the particulate organic carbon (POC) flux and characteristics in Shenzhen Futian mangrove wetlands. This study will combine field experiment with direct observation and sampling in order to quantify the rainfall-driven POC exchange between mangrove wetland surface and tidal creeks; characterize the variations of biogeochemical characteristics of suspended POC in tidal creeks under rainfall conditions; and furthermore understand the effects of low-tide rainfall-runoff processes on the phytoplankton community structure in mangrove wetland tidal creeks. I expect that these results will demonstrate that rainfall freshwater introduction, although negligible relative to the tidal prism, perform disproportionately large amounts of work on mangrove wetland surface sediment, and are an important component of the carbon and nutrient cycles in mangrove wetlands. More importantly, global climate models highlight a possible change in precipitation pattern in Southern China, leading to more and more frequent episodes of heavy precipitation. Therefore, the potential for low-tide rainfall to enhance or disrupt the intertidal zone biogeochemical processes is on the rise and thus a more comprehensive understanding of rainfall-runoff processes on mangrove wetland landscape material cycling is needed.