FORAMINIFERAL DISTRIBUTION IN SURFACE SEDIMENTS OF THE NORTHWESTERN TAIWAN STRAIT AND ITS RESPONSE TO THE COASTAL UPWELLING CURRENT

The foraminiferal distribution in 337 samples of surface sediments collected from the northwestern of Taiwan Strait near the Pingtan Island of Fujian province has been quantitatively analyzed. The study results show that the distribution of the dominant planktonic foraminifera (PF) species of Globigerinoides sacculifer、G. ruber、Globigerina bulloides and the benthic foraminiferal(BF) assemblages are controlled by different water currents. Based on the abundance of the coastal upwelling species G. bulloides, BF nutrient-rich infaunal species and BF assemblages, the distribution and the strength of the coastal upwelling current are evaluated. The most intensive summer coastal upwelling current is located in the southeastern area with a water depth over 40 m, and the eastern area off the Pingtan Island with a water depth more than 20 m. Some areas less than 10 m deep in the central bay are also weakly influenced by it. The shallow water areas close to the continent and island are not influenced by the coastal upwelling current. Due to the influence of the Zhemin alongshore current, the coastal upwelling current is not recorded in some areas between the water depth of 10m and 30 m from the northeastern Pingtan Island to the southwestern Nanri Island.