汉江中下游冬春季硅藻水华成因研究

Study on the Formation of Diatom Blooms in the Middle and Lower Reaches of the Hanjiang River during Winter and Spring

文章通过研究冬春季硅藻水华发生前后汉江中下游水质、水文及气象因素的变化,分析了环境因素对汉江中下游硅藻水华形成的影响。根据研究,汉江中下游硅藻水华发生时,浮游植物中以硅藻门种类最多,且以硅藻门的小环藻生物量最大。统计分析表明,汉江中下游冬春季硅藻生物量与平均气压、pH值、透明度呈显著负相关关系,而与化学需氧量、总氮指标呈显著正相关关系,说明早春季节特有的气候条件(气压值较低)、水文水质条件(枯水期水体流速缓慢、COD及氮含量略高、透明度较低)可能给硅藻生长繁殖创造了适宜条件,是汉江中下游硅藻水华发生的重要影响因素。

According to studying the changes of water quality, hydrology and meteorological factors before and after the diatom blooms occurring during winter and spring, analyzed effects of the environmental factors on the formation of diatom blooms in the middle and lower reaches of the Hanjiang River. According to the research, when diatom blooms occur in the middle and lower reaches of Hanjiang River, the most species are diatoms, and biomass of Cyclotella sp. are the most among all of the diatom species. Results of statistical analysis shows that diatom biomass in spring of the middle and lower reaches of Hanjiang River has significant negative correlation with average pressure, pH and transparency of water, has significantly positive correlation with COD and total nitrogen. It maybe the unique climatic conditions(low pressure), conditions of hydrology and water quality(velocity may slower, COD and nitrogen content may slightly higher, and transparency may lower during dry water flow in early spring) in early spring creating advantageous conditions for diatom’s fast growing, that maybe the important influencing factors in the middle and lower reaches of Hanjiang River diatom bloom’s occurance.