应用qPCR研究三峡库区沉积物中拟多甲藻的动态变化--以汝溪河为例

Study on the Dynamic Changes of Peridiniopsis in the Sediments by Quantitative PCR and Influencing Factors in a Tributary of the Three Gorges Reservoir--A Case Study of Ruxi River

拟多甲藻水华已经成为三峡水库支流的常见水华之一,但其发生过程尚不清楚.为了揭示拟多甲藻在底泥沉积物中的动态变化及其影响因素,采用系统发育和实时荧光定量PCR(qPCR)技术,分析三峡库区支流-汝溪河回水区2016-2017年不同月份3个断面(T1-T3)沉积物中的甲藻.结果表明:底泥沉积物的甲藻为倪氏拟多甲藻(Peridiniopsis niei);3个断面底泥的甲藻基因拷贝数均在3-5月期间达到最大值,且春季细胞数显著高于夏、秋和冬季(p<0.05);3个断面左样点的底泥甲藻基因拷贝数的最大值分别为70.18×10^(3)个/g,68.60×10^(3)个/g和42.77×10^(3)个/g.多元回归分析显示:底泥甲藻拷贝数与泥温、总磷、碳磷比呈线性负相关(p<0.05),而与底泥中的总氮质量分数相关性不大(p>0.05),其中,泥温与春季甲藻拷贝数显著相关,钙和钾显著影响夏季甲藻拷贝数,总氮和总碳分别是秋季和冬季甲藻拷贝数的驱动因子.综合表明:春季是底泥拟多甲藻变化最活跃的时期,底泥甲藻动态变化受温度和营养盐的协同作用.研究为三峡库区甲藻水华的监测和防治提供了新的手段和科学参考.

The occurrence of Peridiniopsis bloom has become one of the common blooms in the tributaries of the Three Gorges Reservoir(TGR),but its occurrence process is still unclear.In order to reveal the dynamic changes of Peridiniopsis in the sediments and influencing factors,the sediment dinoflagellates from three sample points(T1-T3)in the backwater area of Ruxi River,a tributary of the TRG area,were sampled and analyzed from 2016 to 2017 by phylogeny and real-time quantitative fluorescence PCR.The results showed that the dinoflagellate at the sediments of Ruxi River was identified as Peridiniopsis niei.The gene copy number of dinoflagellate in T1,T2 and T3 sections reached the maximum during March to May,and the number of cells in spring was significantly higher than that in summer,autumn and winter(p<0.05).Among them,the copy number of dinoflagellate genes in the left sample points of the three sections reached the maximum in March or May,which were 70.18×10^(3) copies/g dry weight,68.60×10^(3) copies/g dry weight and 42.77×10^(3) copies/g dry weight,respectively.Multiple regression analysis showed that the copy number of dinoflagellate in sediment was linearly and negatively correlated with sediment temperature,TP and C/P(p<0.05),but not with TN content in sediment(p>0.05).Among them,the temperature was significantly correlated with the copy number of dinoflagellate in spring,Ca and K significantly affected the copy number of dinoflagellate in summer,and TN and TC were the main factors affecting the copy number of dinoflagellate in autumn and winter,respectively.The results suggested that spring is the most active period for the dynamics of dinoflagellate in sediment,and the change of dinoflagellate in sediment is synergistically affected by temperature and nutrients.This study provides a new method and scientific reference for the prevention and control of dinoflagellate bloom in the TGR.