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探讨了南海南部海区现代水体和表层沉积中硅藻在属种、丰度上的相关关系及主要的环境控制因素,为南海古环境的对比及重建提供了可靠的依据．分析显示:南海南部的东南海域现代及沉积硅藻丰度较高,且变化趋势相似;西北两者丰度较低,变化趋势有差异．该海区的现代硅藻的优势种为菱形海线藻(Thalassionema nitzschioides)和双头菱形藻(Nitzschia bicapitata),沉积硅藻的优势种为菱形海线藻和短刺角毛藻(Chaetoceros messanensis);相对于现代硅藻,沉积硅藻中减少的是个体相对较小,壳壁较薄的类型,增多的则是个体大、壳壁厚的种类;东南海域现代硅藻的菱形海线藻百分含量高于西北区,沉积硅藻的则变化不大．研究结果认为,西南季风是影响现代硅藻丰度和菱形海线藻百分含量的重要因素,沉积硅藻丰度和菱形海线藻百分含量的分布与西南季风盛行时上层水体硅藻的丰度和菱形海线藻百分含量分布基本一致．
The relationship between species and abundances of diatoms in modern water bodies and surface sediments in the southern South China Sea was discussed. The main environmental control factors were discussed, which provided a reliable basis for the comparison and reconstruction of paleoenvironment in the South China Sea. The analysis shows that the abundance of modern and sedimentary diatoms is relatively high in the southeastern South China Sea, and their changing trend is similar. The abundance of both the northwest and the northwestern parts of the South China Sea is different, with different trends. The dominant species of modern diatoms in this area are Thalassionema nitzschioides and Nitzschia bicapitata, and the dominant species of sedimentary diatoms are Rhododendron chinense and Chaetoceros messanensis. Compared with modern diatoms, sediment diatoms in the reduction of individuals is relatively small, the shell wall is thinner types, the increase is individual large, shell wall thickness of the species; The content is higher than the northwest area, sediment diatoms little change. The results show that the southwest monsoon is an important factor affecting the abundance of modern diatom and the percentage of diamond-shaped sea algae. The distribution of sediment diatom abundance and the percentage of diamond-shaped sea algae is similar to the distribution of diatoms in upper water when the southwest monsoon prevails Abundance and rhodopsin percentage distribution of the same.