人工养殖影响下的潮滩生物地貌学研究

Based on intertidal cultivation on the mudflat，Rudong coast，Jiangsu, we obtain a series of sediment dynamic、microtopography and geographical features with high temporal-spatial resolution using shallow observation instrument. With the combination of sediment dynamic data and mathematical sedimentation model, we analyse influence of intertidal cultivation in normal and storm condition on microtopography dynamic process and bottom sediment characteristics, and investigate the effects and mechanism of biological activity on the stability of tidal flat. Combined with the landform evolution model, we estimated what the role of intertidal cultivation played in Morphodynamics processes. Finally, a scientific hypothesis could be tested: Clam cultivation in the upper part of intertidal mudflat, resulted in sediment porosity increased, and erosion occurred easily, and weaked the formation of concave intertidal mudflat; The laver cultivation in the lower part of intertidal mudflat make hydrodynamic condition weakened, and easy to deposition of sediment, and form a concave intertidal mudflat; During storm period, protective effect of laver cultivation on the intertidal mudflat, but Clam cultivation make intertidal mudflat more easily eroded. The “S” shape was formed from land to sea in the all cultivation area, and was a special intertidal mudflat profile.his project will help to enrich the intertidal organisms geomorphological theory and research methods, and deepen the understanding interaction between biological processes and dynamic sedimentary geomorphological process, and improve the China academic status on coastal biogeomorphology, and provide scientific basis for the development of tide beach resources.

以潮滩养殖影响下江苏如东潮滩为研究对象，采用先进的极浅水观测仪器进行同步联合观测，获取从陆向海潮滩剖面上典型站位的水动力、微地貌和地形地貌等高时空分辨率资料；用沉积动力学资料与数学模型结合，分析正常和风暴潮状况下潮滩养殖（文蛤及紫菜养殖）对微地貌动力过程和沉积物特性的影响，探讨生物活动对潮滩稳定性的影响机制。结合地貌演化模型，评估潮滩养殖在地貌动力过程及演化模式中所扮演的角色。验证工作假说：潮滩中上部文蛤养殖导致沉积物孔隙率增加、抗侵蚀性减弱、易搬运、形成下凹型滩面；潮滩中下部紫菜养殖使水动力减弱、易淤积、形成上凸型滩面；风暴潮期间，紫菜养殖对滩面起保护作用，而文蛤养殖使滩面更易侵蚀；养殖区从陆到海形成S形（上凹下凸）特殊潮滩剖面。该项目有助于丰富潮滩生物地貌学理论和研究方法，加深生物过程和动力-沉积-地貌过程相互作用的认识，提升我国生物地貌学研究的学术地位，为潮滩资源开发提供科学依据。

江苏如东是我国重要的文蛤养殖基地，潮滩养殖对沉积-动力-地貌过程有什么样的影响是一个值得关注的问题，也是研究生物地貌学的天然实验室。因此本项目选择我国最大的潮滩养殖基地作为研究对象，开展开展潮周期内微地貌动力学的探索性研究可丰富生物地貌动力学理论和研究方法。另外，在泥沙供给减少的背景下，有必要进一步从地貌动力过程和机制方面，研究潮滩养殖影响下潮滩微地貌动力过程以及潮滩发育和演化所遵循的模式，评估潮滩养殖在地貌动力过程所扮演的角色，这对丰富生物地貌动力学的理论和研究方法具有重要意义。本项目的研究内容是分别确定在养殖区和相邻非养殖区的沉积动力学参数，研究正常天气状况下和风暴潮影响下潮周期内潮滩养殖对微地貌动力过程的影响，建立在文蛤和紫菜养殖影响下的潮滩演化模型。通过对比分析，评估文蛤和紫菜养殖在潮滩演化中所起的作用，预测如东潮滩在文蛤和紫菜养殖影响下的地貌演化趋势。重要结果表明大型底栖动物文蛤降低了底床稳定性，当底部切应力大于底床临界侵蚀剪切应力时，加速了潮滩侵蚀过程，另一方面当底部切应力小于底床临界侵蚀剪切应力时，加速了潮滩淤积过程。本研究认为这种沉积动力学关键参数的改变 (底床侵蚀临界剪切应力)会对潮滩地貌演化预测模型精度产生重要影响。因此现场沉积动力过程观测和同步大型底栖生物收集，有助于改善浅水环境的水力-沉积和地貌动力学模型的参量化，推动生物地貌学的研究。本研究可以为滩涂资源管理和生态环境的可持续发展提供借鉴，为潮滩湿地的综合管理提供有价值的基础数据和理论支持，以实现区域可持续发展