Wenxin Jiang Changhua Liu Dezhou Yang ^* Lingjing Xu Baoshu Yin

• Institute of Oceanology, Chinese Academy of Sciences (CAS), Qingdao, China

The production of widespread kelp shows a significantly variation in the offshore water of Rongcheng, Shandong Province, China, in 2021. Previous study has shown that red tide is the direct cause of significant environmental changes during the decay process of kelp.The abnormal reduction of kelp production occurred in Rongcheng area of the Yellow Sea in 2021, which is closely related to the red tide. However, the relationship between the red tide event and the hydrodynamic environment remains unclear. In response to these issues To address this red tide event, this study we established a coupled physical-biological model which coupling the ROMS dynamic model with the RED_TIDE biological model for the Yellow Sea and Bohai Sea region, and discussedanalyzed driving factors of this red tide. Based onUsing this coupled model, we investigated various factors influencing the development of red tide were investigated, with a particular focus on analyzing the key factors contributing to the occurrence of the red tide event in the northern sea area ofto the north the Shandong Peninsula in 2021. The aggregation of dinoflagellate cells triggers red tide events. The dominant species of this red tide is dinoflagellate. Thus, Tthe distribution characteristicspattern and concentration changes of dinoflagellate cells were are studied by designing simulation experiments under different conditions to reflect the contributions of various influencing factors to red tide. According toBy analysis of observation data and simulation experiments, this studywe explored the effects of factors such as light conditions, tides, Yellow River runoff and wind field on the distribution and concentration of dinoflagellate cells. The variation ofresults demonstrate that wind field can promote the proliferation and aggregation of dinoflagellate cells, serving as key factors in triggering red tide. The occurrence of red tide is a complex ecological phenomenon influenced by multiple factors, necessitating the comprehensive consideration of these factors to more accurately predict and prevent red tide events.It is necessary to consider these factors comprehensively in order to predict, prevent and control red tide events more accurately .