Objectives: To study the annual variation of diatoms in Zhangweixin River, to provide theoretical support by using diatom examination to estimate the time and place of the corpse entering water, and to establish a diatom database.
Methods: Samples were taken from 4 sampling sites in Decheng section of Zhangweixin River for 12 consecutive months. Non-metric multi-dimensional scaling (NMDS) analysis was performed on the species and content of diatom samples. Based on the sampling site of Tianqu Road, Sprensen similarity coefficient analysis was conducted with the data of other 3 sites in Decheng section and Leling section of Zhangweixin River and Ningjin section in previous studies.
Results: The number of diatom species was positively correlated with diatom content. The average diatom content in different months ranged from 1 054 to 13 041/10 mL, and the species composition ranged from 8 to 16, with differences in dominant species. The similarity coefficient of diatom species within 2 km were all higher than 0.956 52, which could not be distinguished effectively. The similarity coefficients of Leling section and Ningjin section were 0.736 84 and 0.588 24 respectively, which could be effectively distinguished.
Conclusions: The species and content of diatom vary in different months in Zhangweixin River, and the composition of diatom species is different in different basins, which can provide reference for estimating the time and place of the corpse entering water in the river.
目的: 研究漳卫新河硅藻的年度变化规律，为利用硅藻检验判断尸体入水时间、地点提供理论支撑，并建立硅藻数据库。方法: 对漳卫新河德城区段4处采样点连续12个月采样，对样品硅藻种属和含量进行非度量型多维尺度（non-metric multi-dimensional scaling，NMDS）分析，以天衢路采样点为基准，与德城区段其他3处及之前研究中漳卫新河乐陵段和宁津段数据进行Sprensen相似系数分析。结果: 硅藻种类数与硅藻含量呈正相关。不同月份硅藻的平均含量在1 054~13 041个/10 mL，种属构成为8~16个，优势种属存在差异。硅藻种属构成距离2 km以内相似系数均高于0.956 52，不能进行有效区分。在流域跨市县时相似系数有明显差异，与乐陵段采样点相似系数为0.736 84，与宁津段采样点相似系数为0.588 24，可以进行有效区分。结论: 漳卫新河硅藻种属和含量因月份不同具有差异性，硅藻种属构成在不同流域存在差异，可以为判断河流中尸体入水时间和地点提供参考依据。.
Keywords: Shandong; Zhangweixin River; diatom test; drowning; forensic pathology; law of change.